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<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<title>红纸</title>
<link href="/atom.xml" rel="self"/>
<link href="http://www.zhz.io/"/>
<updated>2018-07-05T11:59:04.665Z</updated>
<id>http://www.zhz.io/</id>
<author>
<name>HongZhi</name>
</author>
<generator uri="http://hexo.io/">Hexo</generator>
<entry>
<title>那个LLDB你真的了解吗</title>
<link href="http://www.zhz.io/2018/07/05/%E9%82%A3%E4%B8%AALLDB%E4%BD%A0%E7%9C%9F%E7%9A%84%E4%BA%86%E8%A7%A3%E5%90%97/"/>
<id>http://www.zhz.io/2018/07/05/那个LLDB你真的了解吗/</id>
<published>2018-07-05T11:58:14.000Z</published>
<updated>2018-07-05T11:59:04.665Z</updated>
<content type="html"><![CDATA[<h2 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h2><p>曾经有个笑话（身边的真相）。有次，我要回去写代码的时候呢，我无意间说了一句‘我们回去写BUG吧’。然后传为组内佳话。<br>BUG对于我们程序员来说是无所不在的，你想你的代码没有BUG，除非你没写代码。对于我们iOS or macOS 开发的同学们来说，苹果为我们准备了一个非常良好的Debug的生态环境（LLDB）这使得我们能够非常快速，有效的去排除，解决一些问题。</p><p>那么本文主要以本人平时的开发习惯/<a href="https://developer.apple.com/videos/play/wwdc2018/412/" target="_blank" rel="noopener">WWDC 2018 Session 412</a>/<a href="https://store.raywenderlich.com/products/advanced-apple-debugging-and-reverse-engineering" target="_blank" rel="noopener">Advaced Apple Debug</a>书中部分内容进行如下总结了一些LLDB的命令</p><a id="more"></a><h2 id="LLDB"><a href="#LLDB" class="headerlink" title="LLDB"></a>LLDB</h2><p>作为iOS开发者，我们经常回去设置一些断点，当程序运行到这一行的时候，我们就可以进入LLDB的控制台，去打印一些信息，来辅佐我们进行调试工作。但是我们平常只会去使用p/e命令吧？（至少我以前是这样的。）但是我们今天准备来系统的学习一下LLDB那些比较有作用的命令。在LLDB控制面板中打入help，我们可以看到一堆的命令。今天我准备拿出其中几个用的比较多的来进行说明。</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// Demo代码，下面的说明都会围绕这个代码进行描述</span></div><div class="line"><span class="class"><span class="keyword">@interface</span> <span class="title">HZViewController</span> ()</span></div><div class="line"></div><div class="line"><span class="keyword">@property</span> (<span class="keyword">nonatomic</span>, <span class="keyword">strong</span>) <span class="built_in">NSString</span> *string;</div><div class="line"><span class="keyword">@property</span> (<span class="keyword">nonatomic</span>, <span class="keyword">strong</span>) HZModel *model;</div><div class="line"></div><div class="line"></div><div class="line"><span class="keyword">@end</span></div><div class="line"></div><div class="line"><span class="class"><span class="keyword">@implementation</span> <span class="title">HZViewController</span></span></div><div class="line"></div><div class="line">- (<span class="keyword">void</span>)viewDidLoad</div><div class="line">{</div><div class="line"> [<span class="keyword">super</span> viewDidLoad];</div><div class="line"> <span class="keyword">self</span>.view.backgroundColor = [<span class="built_in">UIColor</span> whiteColor];</div><div class="line"> </div><div class="line">}</div><div class="line"><span class="keyword">@end</span></div></pre></td></tr></table></figure><h2 id="expression"><a href="#expression" class="headerlink" title="expression"></a>expression</h2><p>expression作为我们最常用的指令之一，他的作用<em>执行一个表达式，并将表达式的结果作为结果进行输出</em>，expression的完整语法<br><figure class="highlight python"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">expression <cmd-options> -- <expr></div></pre></td></tr></table></figure></p><ul><li><cmd-options>: 命令参数选项，可以根据<em>help expression</em>进行查看他有哪些命令集合。</cmd-options></li><li><expr>: 表达式部分，也就是代码部分<blockquote><p>expression的简写为e，当你使用默认参数的时候可以不用打–这个多余的符号，但是当你使用参数的时候就必须加上。不过一般来说我们无需手动去进行设置。<br>OK，我们来实践一下。</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 最初String并没有被初始化（e也可以被当做是一个打印命令来打印信息。）</span></div><div class="line">(lldb) e <span class="keyword">self</span>.string</div><div class="line">(<span class="built_in">NSString</span> *) $<span class="number">6</span> = <span class="literal">nil</span></div><div class="line"><span class="comment">// 这个时候我们去执行一段表达式，去修改string的变量</span></div><div class="line">(lldb) e <span class="keyword">self</span>.string = <span class="string">@"TestString"</span></div><div class="line">(<span class="built_in">NSTaggedPointerString</span> *) $<span class="number">7</span> = <span class="number">0xbf4c3b53c7710e1d</span></div><div class="line"><span class="comment">// 我们去打印这个值</span></div><div class="line">(lldb) po <span class="keyword">self</span>.string</div><div class="line">TestString</div></pre></td></tr></table></figure></blockquote></expr></li></ul><h2 id="print"><a href="#print" class="headerlink" title="print"></a>print</h2><p>print相对来说很简单，其实他就是<em>expression – <expr></expr></em>就是一个简化版的e，其简写为p。<br><figure class="highlight python"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">print</span> <expr></div></pre></td></tr></table></figure></p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div></pre></td><td class="code"><pre><div class="line">(lldb) p <span class="keyword">self</span>.string = <span class="string">@"asd"</span></div><div class="line">(<span class="built_in">NSTaggedPointerString</span> *) $<span class="number">12</span> = <span class="number">0xbf623d41451e6fa4</span> <span class="string">@"\372\346Q\324#\366"</span></div><div class="line">(lldb) po <span class="keyword">self</span>.string</div><div class="line">asd</div></pre></td></tr></table></figure><h2 id="po"><a href="#po" class="headerlink" title="po"></a>po</h2><p>如果expression不加任何参数，那么他打印出来的信息都是指针的信息。这对于我们调试来说是非常不方便的。<br>所以expression有一个-O的参数，是用来打印函数对象的，并且他的描述即为，打印具有语言的描述性API。<br>po其实就是<em>expression -O <expr></expr></em>的简写，Xcode团队很人性化的加入了这个东西。当然上面的描述性API就是指的<em>description</em>和<em>debugDescription</em>了。<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div></pre></td><td class="code"><pre><div class="line"><span class="comment">//为上面的代码加入以下代码 HZViewController.m中</span></div><div class="line">- (<span class="built_in">NSString</span> *)debugDescription {</div><div class="line"> <span class="keyword">return</span> [<span class="built_in">NSString</span> stringWithFormat:<span class="string">@" 类名:%@ \n 属性列表：%@"</span>,<span class="built_in">NSStringFromClass</span>(HZViewController.class),HZViewController.hz_propertyKeys];</div><div class="line">}</div><div class="line"></div><div class="line"><span class="comment">// LLDB调试输出</span></div><div class="line">(lldb) po <span class="keyword">self</span> <span class="comment">// 尝试使用po命令还输出self</span></div><div class="line"> 类名:HZViewController </div><div class="line"> 属性列表：(</div><div class="line"> string,</div><div class="line"> model</div><div class="line">)</div><div class="line">(lldb) p <span class="keyword">self</span> </div><div class="line">(HZViewController *) $<span class="number">1</span> = <span class="number">0x00007f934e50f4d0</span></div><div class="line">(lldb) e -O -- <span class="keyword">self</span> <span class="comment">// 对比于po是没有任何区别的</span></div><div class="line"> 类名:HZViewController </div><div class="line"> 属性列表：(</div><div class="line"> string,</div><div class="line"> model</div><div class="line">)</div></pre></td></tr></table></figure></p><h2 id="call"><a href="#call" class="headerlink" title="call"></a>call</h2><p>其实还有一个打印命令是call,对比于其他打印命令来说，他有一个优势在于，他能执行多行代码（但是我觉得比较鸡肋，我从来都没用过）。<br>如果单纯使用<em>call <expr></expr></em>的话他跟e/p无差异。但是你单独使用call，就可以键入多行函数，来执行一些定制化的需求。比如下面这个。<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div></pre></td><td class="code"><pre><div class="line">(lldb) po <span class="keyword">self</span>.view.backgroundColor</div><div class="line"> <span class="literal">nil</span></div><div class="line">(lldb) call <span class="comment">// 进入函数输入控制</span></div><div class="line">Enter expressions, then terminate with an empty line to evaluate:</div><div class="line"><span class="number">1</span> <span class="keyword">if</span> (<span class="keyword">self</span>.view.backgroundColor == <span class="literal">nil</span>) {</div><div class="line"><span class="number">2</span> <span class="keyword">self</span>.view.backgroundColor = [<span class="built_in">UIColor</span> whiteColor];</div><div class="line"><span class="number">3</span> }</div><div class="line">(lldb) po <span class="keyword">self</span>.view.backgroundColor</div><div class="line"><span class="built_in">UIExtendedGrayColorSpace</span> <span class="number">1</span> <span class="number">1</span></div><div class="line">(lldb) call <span class="keyword">self</span>.view.backgroundColor</div><div class="line">(<span class="built_in">UICachedDeviceWhiteColor</span> *) $<span class="number">10</span> = <span class="number">0x0000600001c46070</span></div><div class="line">(lldb) e <span class="keyword">self</span>.view.backgroundColor</div><div class="line">(<span class="built_in">UICachedDeviceWhiteColor</span> *) $<span class="number">11</span> = <span class="number">0x0000600001c46070</span></div></pre></td></tr></table></figure></p><h2 id="p-e-po-call区别"><a href="#p-e-po-call区别" class="headerlink" title="p/e/po/call区别"></a>p/e/po/call区别</h2><table><thead><tr><th>命令</th><th>主要区别</th><th>函数提示</th></tr></thead><tbody><tr><td>e</td><td>打印属性（基础类型：包含函数类型和变量值，对象类型：包含函数指针）</td><td>没有命令行提醒，完全属于盲打</td></tr><tr><td>p</td><td>同e</td><td>终端会根据当前堆栈，提示属性/函数信息</td></tr><tr><td>po</td><td>打印具有平台特性的描述性API（基础类型：打印变量值，对象: 根据描述API输出）</td><td>终端会根据当前堆栈，提示属性/函数信息</td></tr><tr><td>call</td><td>打印功能同e，但是还具备输入多行表达式的功能</td><td>没有命令行提醒，完全属于盲打</td></tr></tbody></table><h2 id="断点"><a href="#断点" class="headerlink" title="断点"></a>断点</h2><p>断点设置命令，可能会有人问了，我用Xcode，在函数边上点一下不就有断点了么，要这个命令有个锤子用？那只能说你作死作的还不够多。当你没有源码的时候，这个命令就成了你的救命稻草。举个🌰，我有个砸过壳的IPA包，纯二进制，你只能通过<em>class-dump</em>或者<em>IDA</em>去获取到一些函数信息，然后你就可以悄然的去用这个命令去设置一些断点，调试当前堆栈里的信息。整个APP都在你的掌控之中。OK，废话B多了，脑子要坏掉的，我们继续来看下这个命令。</p><blockquote><p>breakpoint的缩写为br，后面都会用缩写来进行描写</p></blockquote><h3 id="br-set"><a href="#br-set" class="headerlink" title="br set"></a>br set</h3><p>breakpoint set命令是用来设置断点的，LLDB提供了很多设置断点的方式。<br><figure class="highlight python"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">breakpoint set <cmd-options></div></pre></td></tr></table></figure></p><p><em>使用 -n 来根据名称来设置一个断点</em><br>给所有的init方法设置上断点。<br><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line">(lldb) br set -n init</div><div class="line">Breakpoint 3: 3657 locations. // 可以看到设置了3657的断点 2333333</div><div class="line">(lldb) br list</div><div class="line">Current breakpoints:</div><div class="line">3: name = 'init', locations = 3657, resolved = 3657, hit count = 0</div><div class="line"> 3.1: where = CoreGraphics`ttf::cvt::init(), address = 0x0000000101042ec6, resolved, hit count = 0 </div><div class="line"> 3.2: where = CoreGraphics`ttf::font::init(), address = 0x000000010148c9ca, resolved, hit count = 0 </div><div class="line"> 3.3: where = CoreGraphics`ttf::fpgm::init(), address = 0x0000000101063086, resolved, hit count = 0 </div><div class="line"> 3.4: where = CoreGraphics`ttf::glyf::init(), address = 0x00000001012bacea, resolved, hit count = 0</div></pre></td></tr></table></figure></p><p><em>使用 -f 来根据文件名去配合设置断点</em><br>我只想给HZViewController的init设置断点，其他断点都不要，因为前面设置的断点太多了。<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">(lldb) br set -f HZViewController.m -n init</div><div class="line">Breakpoint <span class="number">3</span>: where = HZTest_Example`-[HZViewController init] + <span class="number">20</span> at HZViewController.m:<span class="number">35</span>, address = <span class="number">0x000000010b6eeba4</span></div></pre></td></tr></table></figure></p><blockquote><p>Note: 文件的使用条件是，这个文件中必须包含有init函数。集成的话是不会被标记出来的。会提示<em>WARNING: Unable to resolve breakpoint to any actual locations.</em></p></blockquote><p><em>使用 -l 来根据文件来指定断点行数</em><br><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div></pre></td><td class="code"><pre><div class="line">26:@property (nonatomic, strong) NSString *string;</div><div class="line">34:- (instancetype)init {</div><div class="line">35: if (self = [super init]) {</div><div class="line">36:</div><div class="line">37: }</div><div class="line">38: return self;</div><div class="line">39:}</div><div class="line">(lldb) br set -l 26 -f HZViewController.m</div><div class="line">Breakpoint 6: 2 locations.</div><div class="line">(lldb) br list</div><div class="line">Current breakpoints:</div><div class="line">6: file = 'HZViewController.m', line = 26, exact_match = 0, locations = 2, resolved = 2, hit count = 0</div><div class="line"> 6.1: where = HZTest_Example`-[HZViewController string] + 12 at HZViewController.m:26, address = 0x000000010f3c2f0c, resolved, hit count = 0 </div><div class="line"> 6.2: where = HZTest_Example`-[HZViewController setString:] + 49 at HZViewController.m:26, address = 0x000000010f3c2f51, resolved, hit count = 0 </div><div class="line">(lldb) br set -l 35 -f HZViewController.m</div><div class="line">Breakpoint 8: where = HZTest_Example`-[HZViewController init] + 20 at HZViewController.m:35, address = 0x000000010f3c2ba4</div><div class="line">(lldb) br list</div><div class="line">Current breakpoints:</div><div class="line">8: file = 'HZViewController.m', line = 35, exact_match = 0, locations = 1, resolved = 1, hit count = 0</div><div class="line"> 8.1: where = HZTest_Example`-[HZViewController init] + 20 at HZViewController.m:35, address = 0x000000010f3c2ba4, resolved, hit count = 0</div></pre></td></tr></table></figure></p><blockquote><p>Note:如果指定的地方是一个属性，那么就会指定其set和get方法，如果指定的地方是一个空白行的地方，则自动向下寻找第一个存在函数的指定行</p></blockquote><p>后面其实都是给前面的命令，新增一些功能而准备的。就不一个个去设置了。</p><ul><li><p><em>-c</em> 用来设置断点条件，比如说我们有时会希望想当一个条件为真的时候，才触发断点操作，那么我们就可以去使用这个东西，对应如果是使用UI去设置的话就是这个选项框</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">br set -n setString: -c string == <span class="string">@"TestString"</span></div></pre></td></tr></table></figure><p><img src="/resources/34E7B233E6285A6B512BFD507DA32887.jpg" alt="IMAGE"></p></li><li><em>-o</em> 来设置单次断点WWDC 2018 Session412中介绍的一点<br><em>-o</em>=<em>–one-shot true</em><br>配合br command add可以达到在某个断点后单次拦截某个函数，有兴趣看怎么操作的可以去看一下这位写的<a href="https://juejin.im/post/5b1cd870e51d4506dc0ac76c" target="_blank" rel="noopener">效率提升爆表的 Xcode 和 LLDB 调试技巧</a></li><li><em>-i</em> 设置执行忽略断点次数，对应的UI设置如图所示。<br><img src="/resources/88734A697D8FDFB43E853DA1F467D086.jpg" alt="IMAGE"></li></ul><table><thead><tr><th>函数</th><th>区别</th></tr></thead><tbody><tr><td>br set -f Test.m –line 12</td><td>给某个文件的12行函数加个断点</td></tr><tr><td>br set –name test</td><td>给所有test 函数加个断点</td></tr><tr><td>br set –method test</td><td>给所有test C++函数加个断点</td></tr><tr><td>br set –selector test</td><td>给所有test OC函数加个断点</td></tr><tr><td>br set –shlib Foundation.framework –name test</td><td>给Foundation库的test函数加个断点</td></tr></tbody></table><h3 id="br-command"><a href="#br-command" class="headerlink" title="br command"></a>br command</h3><p>从上面的set中，我们知道了如何去用代码去设置一个断点。当我们去执行了断点后，我们希望让他去自动的去帮我们去输出一些内容，而不是我们一个个po/e去打印。那么这个command就是为了这个而设计的。从可视化的方式设置的话，就如图所示了。<br><img src="/resources/CD4AB509BE03B60C485114A326132841.jpg" alt="IMAGE"></p><blockquote><p>Note: 其实Xcode提供了很多种类断点后执行的方式，比如执行一段脚本/发出声音/打印信息等等，我们这边只讲打印Debug信息的内容，跟你在LLDB中打印无异。</p></blockquote><p><em>br command list</em> 显示某个断点当前的所有可执行项<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">(lldb) br command list <span class="number">2</span></div><div class="line">Breakpoint <span class="number">2</span>:</div><div class="line"> po <span class="keyword">self</span></div></pre></td></tr></table></figure></p><p><em>br command add</em> 给断点添加一个可执行项<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line">(lldb) br set -n testGlobalPoint -f HZViewController.m</div><div class="line">Breakpoint <span class="number">3</span>: where = HZTest_Example`-[HZViewController testGlobalPoint] + <span class="number">23</span> at HZViewController.m:<span class="number">52</span>, address = <span class="number">0x0000000105396d27</span></div><div class="line">(lldb) br command add -o <span class="string">"po self"</span> <span class="number">3</span></div><div class="line">(lldb) br command list <span class="number">2</span></div><div class="line">Breakpoint <span class="number">2</span>:</div><div class="line"> po <span class="keyword">self</span></div></pre></td></tr></table></figure></p><blockquote><p>Note: 如果你尝试给一个断点添加多个命令，-o是无法满足的，因为-o是–one-line的意思，他只能添加一行。后续的添加会覆盖前面的。<br>所以你可以直接使用br command add 3 (3是断点标识)<br>当然你可以去给断点加个脚本help br command add。可以看到Apple给我们举了一个添加脚本的🌰。虽然我并不知道这玩意儿有啥鸟用<br>小技巧LLDB中有个关键词是contiune,我们可以键入这个去跳过断点，所以我们输入多行的时候就可以这么玩了,这样会跳过断点，但是又会有合理的Log输出<br><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line">(lldb) br command add 3</div><div class="line">Enter your debugger command(s). Type 'DONE' to end.</div><div class="line">> po self</div><div class="line">> continue</div><div class="line">> DONE</div></pre></td></tr></table></figure></p></blockquote><p><em>br command delete</em> 删除一个断点的可执行项<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">(lldb) br command delete <span class="number">3</span></div><div class="line">(lldb) br command list <span class="number">3</span></div><div class="line">Breakpoint <span class="number">3</span> does not have an associated command.</div></pre></td></tr></table></figure></p><h3 id="br-list"><a href="#br-list" class="headerlink" title="br list"></a>br list</h3><p>查看当前设置的断点的列表，enable/disable的都会显示在上面，包含运行期的代码断点和运行前的可视化断点<br>LLDB会默认先读取你在非运行期，设置的断点即在Xcode的函数左边的小箭头，当我们每次设置一次可视化的断点。就会去设置断点文件。<br>文件路径<em>/工程目录//Users/hongzhizhao/Desktop/HZTest/Example/HZTest.xcworkspace/xcuserdata/hongzhizhao.xcuserdatad/xcdebugger/Breakpoints_v2.xcbkptlist</em><br><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line">(lldb) br list</div><div class="line">Current breakpoints:</div><div class="line">1: file = '/Users/xxxxx/Desktop/HZTest/Example/HZTest/HZViewController.m', line = 44, exact_match = 0, locations = 1, resolved = 1, hit count = 0</div><div class="line"></div><div class="line"> 1.1: where = HZTest_Example`-[HZViewController testGlobalPoint] + 23 at HZViewController.m:44, address = 0x0000000100d42d37, resolved, hit count = 0 </div><div class="line"></div><div class="line">2: file = '/Users/xxxx/Desktop/HZTest/Example/HZTest/HZViewController.m', line = 37, exact_match = 0, locations = 1, resolved = 1, hit count = 1</div><div class="line"></div><div class="line"> 2.1: where = HZTest_Example`-[HZViewController viewDidLoad] + 61 at HZViewController.m:37, address = 0x0000000100d42c6d, resolved, hit count = 1</div></pre></td></tr></table></figure></p><h3 id="br-delete"><a href="#br-delete" class="headerlink" title="br delete"></a>br delete</h3><p>顾名思义，删除断点。我们可以通过br list中去找到对应的nuber。(包含二级的也可以。)<br><figure class="highlight python"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">breakpoint delete <span class="comment">#number#</span></div></pre></td></tr></table></figure></p><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div></pre></td><td class="code"><pre><div class="line">(lldb) br set -n init</div><div class="line">Breakpoint 6: 3657 locations.</div><div class="line">(lldb) br list</div><div class="line">Current breakpoints:</div><div class="line">6: name = 'init', locations = 3657, resolved = 3657, hit count = 0</div><div class="line"> 6.3656: where = EmailCore`-[ECEncodedWordEncoder init], address = 0x000000011e6caa14, resolved, hit count = 0 </div><div class="line"> 6.3657: where = CoreRecents`-[CRRecentContactsLibrary init], address = 0x000000011e6dec27, unresolved, hit count = 0 </div><div class="line">(lldb) br delete 6.3657</div><div class="line">0 breakpoints deleted; 1 breakpoint locations disabled.</div><div class="line">(lldb) br list</div><div class="line"> 6.3656: where = EmailCore`-[ECEncodedWordEncoder init], address = 0x000000011e6caa14, resolved, hit count = 0 </div><div class="line"> 6.3657: where = CoreRecents`-[CRRecentContactsLibrary init], address = 0x000000011e6dec27, unresolved, hit count = 0 Options: disabled</div></pre></td></tr></table></figure><h3 id="br-disable-enable"><a href="#br-disable-enable" class="headerlink" title="br disable/enable"></a>br disable/enable</h3><p>有些时候，我们可能根据具体场景设置了一些断点，但是临时开发的时候我们却不想让其进入断点。OK，我们可以去临时改写这个断点的状态为disable,当我们希望其开启的时候再设置为enable就可以了~，perfect？<br><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line">(lldb) br list</div><div class="line">Current breakpoints:</div><div class="line">1: file = '/Users/hongzhizhao/Desktop/HZTest/Example/HZTest/HZViewController.m', line = 44, exact_match = 0, locations = 1, resolved = 1, hit count = 1</div><div class="line"> 1.1: where = HZTest_Example`-[HZViewController viewDidLoad] + 61 at HZViewController.m:44, address = 0x0000000105396c1d, resolved, hit count = 1 </div><div class="line">(lldb) br disable 1</div><div class="line">1 breakpoints disabled.</div><div class="line">(lldb) br list</div><div class="line">Current breakpoints:</div><div class="line">1: file = '/Users/hongzhizhao/Desktop/HZTest/Example/HZTest/HZViewController.m', line = 44, exact_match = 0, locations = 1 Options: disabled </div><div class="line"> 1.1: where = HZTest_Example`-[HZViewController viewDidLoad] + 61 at HZViewController.m:44, address = 0x0000000105396c1d, unresolved, hit count = 1</div></pre></td></tr></table></figure></p><h3 id="br-clear"><a href="#br-clear" class="headerlink" title="br clear"></a>br clear</h3><p>清理指定文件的指定行的断点<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">breakpoint clear -l <span class="meta">#lines# -f #filename#</span></div></pre></td></tr></table></figure></p><p>下面命令为</p><ul><li>查看当前list确实存在一个断点</li><li>使用clear命令清除name为5的断点</li><li>再次查看当前list，name为5确实被移除了<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line">(lldb) br list</div><div class="line">Current breakpoints:</div><div class="line">5: file = '/Users/hongzhizhao/Desktop/HZTest/Example/HZTest/HZViewController.m', line = 48, exact_match = 0, locations = 1, resolved = 1, hit count = 0</div><div class="line"> 5.1: where = HZTest_Example`-[HZViewController testGlobalPoint] + 23 at HZViewController.m:48, address = 0x000000010da39d37, resolved, hit count = 0 </div><div class="line">(lldb) br clear -l 48 -f "HZViewController.m"</div><div class="line">1 breakpoints cleared:</div><div class="line">5: file = '/Users/hongzhizhao/Desktop/HZTest/Example/HZTest/HZViewController.m', line = 48, exact_match = 0, locations = 1, resolved = 1, hit count = 0</div><div class="line"></div><div class="line">(lldb) br list</div><div class="line">Current breakpoints:</div></pre></td></tr></table></figure></li></ul><h3 id="br-read-write"><a href="#br-read-write" class="headerlink" title="br read/write"></a>br read/write</h3><p>我们前面讲list的时候，我们讲到过一些存储断点相关的东西，<em>br write -f #file_path#</em>，-f标识断点文件的存储路径。<br>前面说了这么多的断点设置，其实都是运行期的设置，出了运行期，这些设置都是没有了的。所以read/write是一个持久保存的方案。<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line">(lldb) br write -f ~/Desktop/a.log</div><div class="line">(lldb) br read -f ~/Desktop/a.log</div><div class="line">New breakpoints:</div><div class="line">Breakpoint <span class="number">4</span>: where = HZTest_Example`-[HZViewController viewDidLoad] + <span class="number">61</span> at HZViewController.m:<span class="number">44</span>, address = <span class="number">0x0000000105396c1d</span></div><div class="line">Breakpoint <span class="number">5</span>: where = HZTest_Example`-[HZAppDelegate application:didFinishLaunchingWithOptions:] + <span class="number">73</span> at HZAppDelegate.m:<span class="number">16</span>, address = <span class="number">0x0000000105396719</span></div><div class="line">Breakpoint <span class="number">6</span>: where = HZTest_Example`-[HZViewController testGlobalPoint] + <span class="number">23</span> at HZViewController.m:<span class="number">52</span>, address = <span class="number">0x0000000105396d27</span></div></pre></td></tr></table></figure></p><blockquote><p>Note: read并不能读取Xcode使用可视化设置的埋点，可能跟版本有关系吧，可视化埋的断点，是V2版本的。但是使用命令的并没有版本标识，可视化埋点是xml,使用命令保存的却是json文件。另外read并是一个会去替换的更新，而是一个读取后全部添加~</p></blockquote><h2 id="属性监听-watchpoint"><a href="#属性监听-watchpoint" class="headerlink" title="属性监听 watchpoint"></a>属性监听 watchpoint</h2><p>OK，我们看到了如何去设置一个函数的断点。但是有些时候，我们可能并不满足于函数，需要去监听一些属性的变化。那么有些人就会说，我直接监听set方法不就好了？那么就会有两种情况不会过set方法，1.直接调用的是<em>_</em> 2.这个属性压根就没有getter和setter方式是一个纯只指针的访问形式呢？你监听给我看看？<br>所以watchpoint就是这么一个神奇的东西，说白了他是监听一个内存地址的变化，所以他能够去捕获变量的变化。</p><blockquote><p>watchpoint 跟breakpoint的命令大致相同，只是一个操作函数，一个操作地址罢了</p></blockquote><h3 id="watchpoint-set"><a href="#watchpoint-set" class="headerlink" title="watchpoint set"></a>watchpoint set</h3><p><em>watchpoint set variable <var></var></em><br>跟设置函数一样的去设置一个断点<br><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line">(lldb) watchpoint set variable self.window</div><div class="line">error: "self" is a pointer and . was used to attempt to access "window". Did you mean "self->window"?</div><div class="line">(lldb) watchpoint set variable self->_window</div><div class="line">Watchpoint created: Watchpoint 1: addr = 0x600000ccc110 size = 8 state = enabled type = w</div><div class="line"> watchpoint spec = 'self->_window'</div><div class="line"> new value: 0x00007fc8b780d600</div></pre></td></tr></table></figure></p><blockquote><p>由于watchpoint是一个内存块的监听策略，如果我们去写self.window这种表达式，实质是在设置[self setWindow:]方法，那么跟他的定义就大相径庭了。这边举个例子</p></blockquote><p><em>watchpoint set expression <expr></expr></em><br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">(lldb) watchpoint set expression <span class="number">0x00007fc8b780d600</span></div><div class="line">Watchpoint created: Watchpoint <span class="number">2</span>: addr = <span class="number">0x7fc8b780d600</span> size = <span class="number">8</span> state = enabled type = w</div><div class="line"> new value: <span class="number">4440870480</span></div></pre></td></tr></table></figure></p><p><em>-w统一参数</em><br>read/write/read_write<br>从字面意思上，我们就可以看出是监听的内容是读还是写还是读写一起监听。默认是写操作</p><blockquote><p>variable/expression的区别应用<br>variable必须是你进入了某次断点，才能够用使用当前栈中使用的属性去监听<br>expression 你可以通过一些逆向软件来计算偏移量+首地址的形式去得到最终的内存地址</p></blockquote><h3 id="watchpoint-list"><a href="#watchpoint-list" class="headerlink" title="watchpoint list"></a>watchpoint list</h3><p>这个我们就不多说了，查看当前的watchpoint列表<br><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div></pre></td><td class="code"><pre><div class="line">(lldb) watchpoint list</div><div class="line">Number of supported hardware watchpoints: 4</div><div class="line">Current watchpoints:</div><div class="line">Watchpoint 1: addr = 0x600000ccc110 size = 8 state = enabled type = w</div><div class="line"> watchpoint spec = 'self->_window'</div><div class="line"> new value: 0x00007fc8b780d600</div><div class="line">Watchpoint 2: addr = 0x7fc8b780d600 size = 8 state = enabled type = w</div><div class="line"> new value: 4440870480</div></pre></td></tr></table></figure></p><blockquote><p>这边我们看到使用expression和variable会得到两条结果</p></blockquote><h3 id="watchpoint-delete"><a href="#watchpoint-delete" class="headerlink" title="watchpoint delete"></a>watchpoint delete</h3><p>删除一个监测点<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">(lldb) watch delete <span class="number">1</span></div><div class="line"><span class="number">1</span> watchpoints deleted.</div></pre></td></tr></table></figure></p><h3 id="watchpoint-disable-enable"><a href="#watchpoint-disable-enable" class="headerlink" title="watchpoint disable/enable"></a>watchpoint disable/enable</h3><p>跟breakpoint一样，他也有一个临时关闭和打开的设置开关<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div></pre></td><td class="code"><pre><div class="line">(lldb) watchpoint disable <span class="number">3</span></div><div class="line"><span class="number">1</span> watchpoints disabled.</div><div class="line">(lldb) watchpoint enable <span class="number">3</span></div><div class="line"><span class="number">1</span> watchpoints enabled.</div></pre></td></tr></table></figure></p><h3 id="watchpoint-ignore"><a href="#watchpoint-ignore" class="headerlink" title="watchpoint ignore"></a>watchpoint ignore</h3><p>一个断点在真正被执行前需要被断点几次？<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">(lldb) watchpoint ignore -i <span class="number">3</span> <span class="number">3</span></div><div class="line"><span class="number">1</span> watchpoints ignored.</div></pre></td></tr></table></figure></p><h3 id="watchpoint-modify"><a href="#watchpoint-modify" class="headerlink" title="watchpoint modify"></a>watchpoint modify</h3><p>当条件为真的时候，采取真正执行断点<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">(lldb) watchpoint modify -c <span class="string">"self ==nil"</span> <span class="number">3</span></div><div class="line"><span class="number">1</span> watchpoints modified.</div></pre></td></tr></table></figure></p><h3 id="watchpoint-command"><a href="#watchpoint-command" class="headerlink" title="watchpoint command"></a>watchpoint command</h3><p>这个跟breakpoint command 没有任何区别，这边就不去说这个东西了。</p><h2 id="控制程序-thread"><a href="#控制程序-thread" class="headerlink" title="控制程序 thread"></a>控制程序 thread</h2><p>说完了如何去调试你的代码，但是有的时候这往往是不够的。我们希望于去控制我们的程序走向。例如一个函数的返回值，会改变程序的走向，那么我希望去改变他的返回值。这个时候我们就可以用到thread这个命令来辅佐我们。我们日常用的step调试，其实都是thread命令，只是Xcode帮我们可视化了罢了。</p><h3 id="thread-return"><a href="#thread-return" class="headerlink" title="thread return"></a>thread return</h3><p>return顾名思义，直接使函数return,return后面可以接表达式，来帮助我们返回一些有利于我们调试的东西<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">thread <span class="keyword">return</span> [<expr>]</div></pre></td></tr></table></figure></p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line">- (<span class="keyword">void</span>)testReturn {</div><div class="line"> <span class="built_in">NSString</span> *a = [<span class="keyword">self</span> testReturn] ? <span class="string">@"a"</span> : <span class="string">@"b"</span>;</div><div class="line">}</div><div class="line">- (<span class="built_in">BOOL</span>)testReturn {</div><div class="line"> <span class="keyword">return</span> <span class="literal">true</span>;</div><div class="line">}</div><div class="line">(lldb) thread <span class="keyword">return</span> <span class="literal">false</span></div><div class="line">(lldb) po a</div><div class="line">b</div></pre></td></tr></table></figure><h3 id="thread-step-x"><a href="#thread-step-x" class="headerlink" title="thread step-x"></a>thread step-x</h3><p>我们平时的单步调试，其实都来自于这个命令<br><img src="/resources/8D06BDE637F8450D713B1DA6B5814F49.jpg" alt="IMAGE"><br>|命令|作用|<br>|–|–|<br>| thread countinue/c/countinue |等同于第一个按钮，标识程序继续运行|<br>| thread step-over/n/next | 等同于第二个按钮，单步运行 |<br>| thread step-in/s/step | 等同于第三个按钮，进入函数方法内部 源码级别|<br>| thread step-out/finish | 等同于第四个按钮，跳出当前函数 |</p><h3 id="thread-jump"><a href="#thread-jump" class="headerlink" title="thread jump"></a>thread jump</h3><p>OK，这玩意儿真的是一个黑魔法。看WWDC2018,断点移动的我一愣一愣的。来感受一下？<br><img src="/resources/64AC4E1386A9032ED73A4E7B68E4B08D.gif =1052x682" alt="未命名.gif"><br>其实这个东西很简单，老早就有了，只是我不知道罢了。<br><em>thread jump -l <linenum></linenum></em>上面的图是可视化的罢了，这个才是实质代码。-l 输入跳转的代码。</p><blockquote><p>Note:且用且珍惜，这东西有利有弊</p></blockquote><h3 id="其他东西"><a href="#其他东西" class="headerlink" title="其他东西"></a>其他东西</h3><ul><li>thread list 列出当前所有的线程</li><li>thread select 选择某个线程</li><li>therad until 传入一个行数，让程序执行到这行的时候暂停</li><li>thread info 输出当前线程的信息</li><li>thread backtrace 断点的函数调用堆栈，默认当前线程</li><li>thread plan 用来管理当前线程的执行计划</li></ul><blockquote><p>thread命令虽好，但是随意改变成语的走向，可能会引起一些不必要的麻烦</p></blockquote><h2 id="查看调用栈-frame"><a href="#查看调用栈-frame" class="headerlink" title="查看调用栈 frame"></a>查看调用栈 frame</h2><p>在我们调试过程中，我们经常能看到，控制台帮我们输出了当前的调用栈内容。其实他对应的就是frame命令。<br><img src="/resources/DEE2D7DF3DC22831BDEE012AE6FAE029.jpg" alt="IMAGE"><br>细心的同学可能会看到一个细节，红框1和红框2是对应的，红框2是用thread backtrace打印出来的。里面的frame其实就是我们这面的frame,我们可以通过<em>frame select <num></num></em>来使用代码切换当前运行的调用栈，跟你手动点现况1的没有任何区别<br><img src="/resources/1520BBE8DC414066748F4082CA2A4DDB.jpg" alt="IMAGE"><br><em>frame variable</em>用来打印当前调用栈内的所有属性<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div></pre></td><td class="code"><pre><div class="line">(lldb) frame variable</div><div class="line">(HZViewController *) <span class="keyword">self</span> = <span class="number">0x00007f8c6540ba90</span></div><div class="line">(SEL) _cmd = <span class="string">"viewDidLoad"</span></div><div class="line">(__NSCFConstantString *) a = <span class="number">0x000000010fffa128</span> <span class="string">@"b"</span></div></pre></td></tr></table></figure></p><p><em>frame info</em>打印当前栈的内容<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">(lldb) frame info</div><div class="line">frame <span class="meta">#0: 0x000000010fff7c64 HZTest_Example`-[HZViewController viewDidLoad](self=0x00007f8c6540ba90, _cmd=<span class="meta-string">"viewDidLoad"</span>) at HZViewController.m:52</span></div></pre></td></tr></table></figure></p><h2 id="help-apropos"><a href="#help-apropos" class="headerlink" title="help/apropos"></a>help/apropos</h2><p>当然说了这么多，很多时候我们肯定会忘掉的~啧啧啧，谁还能记住这么多呢，毕竟Xcode帮我们做好了可视化这么好的东西。<br>但是有些时候，我们却不得不去找这些命令，比如逆向的时候。2333333<br>help很简单，帮助我们去打印描述信息的。例如我想知道frame的相关信息，我们就可以这么操作，里面都帮我们写好了<br><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div></pre></td><td class="code"><pre><div class="line">(lldb) help frame</div><div class="line"> Commands for selecting and examing the current thread's stack frames.</div><div class="line"></div><div class="line">Syntax: frame <subcommand> [<subcommand-options>]</div><div class="line"></div><div class="line">The following subcommands are supported:</div><div class="line"></div><div class="line"> info -- List information about the current stack frame in the current</div><div class="line"> thread.</div><div class="line"> select -- Select the current stack frame by index from within the</div><div class="line"> current thread (see 'thread backtrace'.)</div><div class="line"> variable -- Show variables for the current stack frame. Defaults to all</div><div class="line"> arguments and local variables in scope. Names of argument,</div><div class="line"> local, file static and file global variables can be</div><div class="line"> specified. Children of aggregate variables can be specified</div><div class="line"> such as 'var->child.x'.</div><div class="line"></div><div class="line">For more help on any particular subcommand, type 'help <command> <subcommand>'.</div></pre></td></tr></table></figure></p><p>apropos，是一个搜索命令，帮我们查找有哪些命令可以使用，例如下图这样，我们就能够答应出关于step的所有命令来帮助我们来使用<br><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div></pre></td><td class="code"><pre><div class="line">(lldb) apropos step</div><div class="line">The following commands may relate to 'step':</div><div class="line"> thread step-in -- Source level single step, stepping into calls. </div><div class="line"> Defaults to current thread unless specified.</div><div class="line"> thread step-inst -- Instruction level single step, stepping into calls. </div><div class="line"> Defaults to current thread unless specified.</div><div class="line"> thread step-inst-over -- Instruction level single step, stepping over calls. </div><div class="line"> Defaults to current thread unless specified.</div><div class="line"> thread step-out -- Finish executing the current stack frame and stop</div><div class="line"> after returning. Defaults to current thread unless</div><div class="line"> specified.</div><div class="line"> thread step-over -- Source level single step, stepping over calls. </div><div class="line"> Defaults to current thread unless specified.</div></pre></td></tr></table></figure></p><h2 id="Extension"><a href="#Extension" class="headerlink" title="Extension"></a>Extension</h2><h3 id="刷新UI"><a href="#刷新UI" class="headerlink" title="刷新UI"></a>刷新UI</h3><p>即使你改了UI的属性，因为程序暂停，你是无法刷新UI的，但是有个命令可以帮你，这样做你就可以及时的帮助你来改变UI的刷新，即使他在断点的状态<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">e <span class="built_in">CATransaction</span>.flush()</div></pre></td></tr></table></figure></p><h3 id="使用别人写好的脚本"><a href="#使用别人写好的脚本" class="headerlink" title="使用别人写好的脚本"></a>使用别人写好的脚本</h3><p>LLDB是支持使用别人写好的命令的，实质语法是使用python写的，这边就不多做介绍了。有兴趣可以去了解一下</p><h3 id="别名功能"><a href="#别名功能" class="headerlink" title="别名功能"></a>别名功能</h3><p>很多时候命令很长，我们记不住怎么办。比如那个刷新UI的命令。好长啊，在Session里面，这个人有个恶趣味用🚽来代替那个命令。<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">command alias 🚽 e <span class="built_in">CATransaction</span>.flush()</div></pre></td></tr></table></figure></p><h2 id="参考"><a href="#参考" class="headerlink" title="参考"></a>参考</h2><p><a href="https://www.jianshu.com/p/268ecb3cf4c6" target="_blank" rel="noopener">iOS 常用的lldb命令</a><br><a href="https://juejin.im/entry/58c75b258ac24707201369c4" target="_blank" rel="noopener">使用 LLDB 调试 APP</a><br><a href="http://ios.jobbole.com/83393/" target="_blank" rel="noopener">熟练使用 LLDB，让你调试事半功倍</a></p>]]></content>
<summary type="html">
<h2 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h2><p>曾经有个笑话（身边的真相）。有次，我要回去写代码的时候呢，我无意间说了一句‘我们回去写BUG吧’。然后传为组内佳话。<br>BUG对于我们程序员来说是无所不在的，你想你的代码没有BUG，除非你没写代码。对于我们iOS or macOS 开发的同学们来说，苹果为我们准备了一个非常良好的Debug的生态环境（LLDB）这使得我们能够非常快速，有效的去排除，解决一些问题。</p>
<p>那么本文主要以本人平时的开发习惯/<a href="https://developer.apple.com/videos/play/wwdc2018/412/" target="_blank" rel="noopener">WWDC 2018 Session 412</a>/<a href="https://store.raywenderlich.com/products/advanced-apple-debugging-and-reverse-engineering" target="_blank" rel="noopener">Advaced Apple Debug</a>书中部分内容进行如下总结了一些LLDB的命令</p>
</summary>
</entry>
<entry>
<title>WWDC 2018 - 412 Advanced Debugging With Xcode and LLDB</title>
<link href="http://www.zhz.io/2018/06/10/WWDC-2018-412-Advanced-Debugging-With-Xcode-and-LLDB/"/>
<id>http://www.zhz.io/2018/06/10/WWDC-2018-412-Advanced-Debugging-With-Xcode-and-LLDB/</id>
<published>2018-06-10T02:19:44.000Z</published>
<updated>2018-06-11T01:28:40.775Z</updated>
<content type="html"><![CDATA[<h2 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h2><p>刚做完了这个<a href="https://developer.apple.com/videos/play/wwdc2018/412/" target="_blank" rel="noopener">Advanced Debugging with Xcode and LLDB Session 412</a>的听力练习，来写个小总结(嗯，又可以愉快的开始装逼了)。<br>由于Swift写的不多，可能有几个小部分了解的并不是很全面</p><h2 id="增加了Swift-Debug的可靠性"><a href="#增加了Swift-Debug的可靠性" class="headerlink" title="增加了Swift Debug的可靠性"></a>增加了Swift Debug的可靠性</h2><h3 id="Swift第三方库导入方式不正确，导致的属性无法打印问题修正"><a href="#Swift第三方库导入方式不正确，导致的属性无法打印问题修正" class="headerlink" title="Swift第三方库导入方式不正确，导致的属性无法打印问题修正"></a>Swift第三方库导入方式不正确，导致的属性无法打印问题修正</h3><p>产生原因可以直接看这个<a href="https://juejin.im/post/5a52d7cdf265da3e4c07a004" target="_blank" rel="noopener">链接</a><br>实际产生的效果<br><img src="/resources/C377778880889F7F0B8897607C911E7A.jpg" alt="IMAGE"></p><h3 id="控制台Swift类型修正"><a href="#控制台Swift类型修正" class="headerlink" title="控制台Swift类型修正"></a>控制台Swift类型修正</h3><p><img src="/resources/CDA3BBFB82087B559010B162AAF25A8F.jpg" alt="IMAGE"><br><a id="more"></a></p><h2 id="Debug技巧"><a href="#Debug技巧" class="headerlink" title="Debug技巧"></a>Debug技巧</h2><p>之前看了会儿Advanced Apple Debugging这本书，其实好像上面很多都有写。</p><h3 id="多一个工作区的Debug-Tab给开发者来调试"><a href="#多一个工作区的Debug-Tab给开发者来调试" class="headerlink" title="多一个工作区的Debug Tab给开发者来调试"></a>多一个工作区的Debug Tab给开发者来调试</h3><p>当你进入Debug的时候会多出一个Tab来，当然这个并不是默认打开的，你可以去设置里面进行打开<br><img src="/resources/BBC36F839054F738B10C5FD527CFF6A0.jpg" alt="IMAGE"><br><img src="/resources/C56CA051961A7A531A13F4D930D5A098.jpg" alt="IMAGE"><br>Xcode提供了很多选项可供你选择，在Build/Test/Run等的场景开始或者是暂停的时候弹出新的Tab，可定制型还是挺高的。</p><h3 id="Expression交换函数结果"><a href="#Expression交换函数结果" class="headerlink" title="Expression交换函数结果"></a>Expression交换函数结果</h3><p>利用expression命令,简写为e,来修改属性的值<br><img src="/resources/285E4FC01E01462E29BBD1BE7DCBF7FD.jpg" alt="IMAGE"><br>当然如果你不想每次运行的时候都这么来敲一遍的话，你可以这么玩<br><img src="/resources/BE23B42AD0FC3BFF07F41C9EAF378E18.jpg" alt="IMAGE"><br>OK，甚至你忘记写某句代码了，但是编译又贼慢，你可以学习一下视频里的这个操作<br><img src="/resources/BC89285073DADF1D47C47A249F9898A9.jpg" alt="IMAGE"><br>图中他少设置了一个Delegate，但是他懒啊，直接用断点添加上，然后假装写一行代码在那（其实他并没有编译咯）。但是这样可以假装写了一个代理赋值。Amazing?</p><h3 id="breakpoint-set-–one-shot-true"><a href="#breakpoint-set-–one-shot-true" class="headerlink" title="breakpoint set –one-shot true"></a>breakpoint set –one-shot true</h3><p>OK，看到这个命令一开始是懵逼的，什么鬼东西。但是看到下图应该并不会很陌生，这个是对于UILabel的text字段的全局断点，但是系统的所有设置都会起作用。所以调试的时候还要开关断点啊什么的太麻烦了。所以可以利用上面的这个命令来进行一个修正优化。<br><img src="/resources/0C09C7A80D42093D1A8BACABE50080A8.jpg" alt="IMAGE"><br>我想要在if的判断后面拦截一次-[UILabel setText:]我就可以这么做了<br><img src="/resources/04B30B8BF791028055DA84C3E9FF1A4A.jpg" alt="IMAGE"><br><img src="/resources/4DC633FC7E0FAF3D67388A288A115420.jpg" alt="IMAGE"></p><blockquote><p>Note: 这边写了one shot 所以我在想有没有断两次的操作，但是在同一个断点设置两次command是没有起作用的。<br>–name只是这个命令的其中一个用法，还有其他用法大家自己探索</p></blockquote><h3 id="断点移动"><a href="#断点移动" class="headerlink" title="断点移动"></a>断点移动</h3><p>ヾ(｡｀Д´｡)我擦这是什么操作？来段Gif来表达一下我的忧伤，恕我年少无知。<br><img src="/resources/64AC4E1386A9032ED73A4E7B68E4B08D.gif" alt="未命名.gif"><br>！！！运行中的断点竟然还能移动，关键是还能够回退执行。OK，回到正题，这应该是之前就有的吧，我只是不知道而已。视频中介绍了另外一种姿势，我们来学习一下。图中，这句jump的动画被泰国了，执行了手动执行的动画，并且为false。<br><img src="/resources/8561122F2D0DFE9BFF98E8ABF62EDFEA.jpg" alt="IMAGE"></p><h3 id="watch-point-属性的监听"><a href="#watch-point-属性的监听" class="headerlink" title="watch point 属性的监听"></a>watch point 属性的监听</h3><p>OK，这就像是运行期的KVO 中set炒作一样理解就OK了。<br>当我们在属性列表里面Watch了之后，就可以捕获到这个属性的变化了<br><img src="/resources/96CC650A97A1106370FBF1FC7D87AEB7.jpg" alt="IMAGE"><br><img src="/resources/E5F2CE69A63044C3CF887BBC228A8778.jpg" alt="IMAGE"></p><h3 id="老生常谈的Swift调用OC"><a href="#老生常谈的Swift调用OC" class="headerlink" title="老生常谈的Swift调用OC"></a>老生常谈的Swift调用OC</h3><p>在用Swift的时候，有些OC函数是无法在LLDB中使用的。like view.recursiveDescription。<br><figure class="highlight python"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">expression -l objc -O -- <expr></div></pre></td></tr></table></figure></p><p><img src="/resources/5DFB3DE6902432B7376AB079104F19E2.jpg" alt="IMAGE"></p><h3 id="断点中，界面刷新"><a href="#断点中，界面刷新" class="headerlink" title="断点中，界面刷新"></a>断点中，界面刷新</h3><p>有时候我们进入了断点，在断点的时候，修改了Frame，但是因为被暂停UI是不会刷新的，所以我们可以手动去调用刷新<em>expression CATransaction.flush()</em>已达到界面刷新的效果</p><h3 id="别名"><a href="#别名" class="headerlink" title="别名"></a>别名</h3><p>这个没什么好讲的吧，给刚才的命令取一个简短的名字方便调用罢了<br><figure class="highlight python"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">command alias poc expression -l objc -O --</div><div class="line">command alias 🚽 expression -l objc -- (void)[CATransaction flush]</div></pre></td></tr></table></figure></p><p>(用🚽来刷新也是骚的)</p><h3 id="用LLDB-Python库来自定义命令"><a href="#用LLDB-Python库来自定义命令" class="headerlink" title="用LLDB-Python库来自定义命令"></a>用LLDB-Python库来自定义命令</h3><p>这部分还是参考别人的文章看看吧<a href="http://southpeak.github.io/2015/01/25/tool-lldb/" target="_blank" rel="noopener">LLDB调试器使用简介</a>,反正以前就有了。</p><h3 id="Xib的约束拷贝"><a href="#Xib的约束拷贝" class="headerlink" title="Xib的约束拷贝"></a>Xib的约束拷贝</h3><p>断点的时候进入ViewDebug可以点击相关约束后进行拷贝。在命令行进行粘贴，这样你就能拿到约束对象的地址，进行调试。改完之后要记得刷新界面哦~<br><img src="/resources/C946596F700C273F1E9207A19E9CC749.jpg" alt="IMAGE"><br><img src="/resources/00A0909FA1EA8064E74D401361AFC5A7.jpg" alt="IMAGE"></p><h3 id="其他"><a href="#其他" class="headerlink" title="其他"></a>其他</h3><p>剩下的是dark mode和color的东西，并不是很有兴趣，自行观赏</p><h2 id="总结"><a href="#总结" class="headerlink" title="总结"></a>总结</h2><p>这些都只是入门操作，<a href="https://store.raywenderlich.com/products/advanced-apple-debugging-and-reverse-engineering" target="_blank" rel="noopener">进阶入门</a>更多的这本书里面写的更详细一点吧。<br>这些都是提高自己工作效率的东西，但是关键还是在于理解和实战，只有配合好了才能够发挥出最大的效益。单单只有了解就只是个装饰品罢了。 </p>]]></content>
<summary type="html">
<h2 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h2><p>刚做完了这个<a href="https://developer.apple.com/videos/play/wwdc2018/412/" target="_blank" rel="noopener">Advanced Debugging with Xcode and LLDB Session 412</a>的听力练习，来写个小总结(嗯，又可以愉快的开始装逼了)。<br>由于Swift写的不多，可能有几个小部分了解的并不是很全面</p>
<h2 id="增加了Swift-Debug的可靠性"><a href="#增加了Swift-Debug的可靠性" class="headerlink" title="增加了Swift Debug的可靠性"></a>增加了Swift Debug的可靠性</h2><h3 id="Swift第三方库导入方式不正确，导致的属性无法打印问题修正"><a href="#Swift第三方库导入方式不正确，导致的属性无法打印问题修正" class="headerlink" title="Swift第三方库导入方式不正确，导致的属性无法打印问题修正"></a>Swift第三方库导入方式不正确，导致的属性无法打印问题修正</h3><p>产生原因可以直接看这个<a href="https://juejin.im/post/5a52d7cdf265da3e4c07a004" target="_blank" rel="noopener">链接</a><br>实际产生的效果<br><img src="/resources/C377778880889F7F0B8897607C911E7A.jpg" alt="IMAGE"></p>
<h3 id="控制台Swift类型修正"><a href="#控制台Swift类型修正" class="headerlink" title="控制台Swift类型修正"></a>控制台Swift类型修正</h3><p><img src="/resources/CDA3BBFB82087B559010B162AAF25A8F.jpg" alt="IMAGE"><br>
</summary>
<category term="WWDC" scheme="http://www.zhz.io/tags/WWDC/"/>
</entry>
<entry>
<title>记一次 Alfred Workflow中Confluence改造</title>
<link href="http://www.zhz.io/2018/05/18/%E8%AE%B0%E4%B8%80%E6%AC%A1-Alfred-Workflow%E4%B8%ADConfluence%E6%94%B9%E9%80%A0/"/>
<id>http://www.zhz.io/2018/05/18/记一次-Alfred-Workflow中Confluence改造/</id>
<published>2018-05-18T06:08:18.000Z</published>
<updated>2018-05-18T06:10:37.918Z</updated>
<content type="html"><![CDATA[<h2 id="起因"><a href="#起因" class="headerlink" title="起因"></a>起因</h2><p>Confluence对于企业来说是一个非常有用的文档管理工具，但是每次我在使用的时候，我都要去进行一遍文档空间的目录查找。<br>虽然提供了搜索功能，但是搜索的延时，使用便捷度，都存在一定的问题。（哦，对了我们的Confluence是比较低版本的，太老了，一次搜索50条）<br>那么，想了一下如何去解决这个问题呢，Mac中万能的Alfred Workflow就是用来解决一系列的工作效率的问题的。<br>所以我在尝试能不能用Alfred Workflow来进行文档标题的搜索。<br>OK做这个事情之前，先找下目前有没有已经存在的包拿来直接使用。<br>找到了这个<a href="https://github.com/skleinei/alfred-confluence" target="_blank" rel="noopener">Alfred Workflow</a>，但是按照他的设置却发现搜索不了结果。<br><a id="more"></a></p><h2 id="解决"><a href="#解决" class="headerlink" title="解决"></a>解决</h2><p>OK，我们都知道Alfred Workflow是用python写的，- -好吧，Python早忘光了，反正语言嘛，80%都一样的，就随便改改好了。<br>OK，在Debug信息中我们发现，大神写的脚本的链接直接报了404<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">14:28:40 alfred-confluence.py:99 DEBUG Quick Search URL: http://host/json/contentnamesearch.action/rest/quicknav/1/search?os_authType=basic&query=ios</div><div class="line">14:28:40 workflow.py:2243 ERROR HTTP Error 404: Not Found</div></pre></td></tr></table></figure></p><p>那么我们来找下公司的搜索按钮的URL来试试？<br><a href="http://host/dosearchsite.action?spaceSearch=false&queryString=" target="_blank" rel="noopener">http://host/dosearchsite.action?spaceSearch=false&queryString=</a><br>好像也有问题，因为他输出的是Html内容，我并不能去解析Html的东西，哇贼烦，看看有没有Rest API可以直接调用。<br>既然是Confluence，应该有API文档的吧，找到公司的Confluence版本，然后Google了一番，找到了这个<a href="https://docs.atlassian.com/DAC/rest/confluence/4.3.7.html" target="_blank" rel="noopener">链接</a>看到了图片中的这个，哇这个不就是我们想要的么。<br><img src="/resources/C11BDD5598E2284CFDA97A55806AC3EF.jpg" alt="IMAGE"><br><img src="/resources/C3533F3284F01E0B5AB879A8E173EEFD.jpg" alt="IMAGE"><br>OK，我们直接把链接给复制进去，改了下host。然后进行DEBUG，哇爆炸，还是不行。拿到的参数不是JSON，大神写的无法解析。<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">14:36:21 alfred-confluence.py:99 DEBUG Quick Search URL: http://hots/rest/prototype/1/search?os_authType=basic&query=ios&spaceKey=xxxx&pageSize=10</div><div class="line">14:36:25 workflow.py:2243 ERROR No JSON object could be decoded</div></pre></td></tr></table></figure></p><p>OK，我们去直接用阅览器访问链接（因为阅览器有登录Cookie，所以可以直接进行访问），得到的数据是XML，哇爆炸，贼不想搞这东西。<br>但是没办法，还是要用的。<br>那么问题处在XML没办法解析，得不到最终的数据。那么就来解析XML吧，- -我个人喜欢JSON，直接去Google了一个XML转JSON的库，来做（主要是，试了好几个自己写的转换莫名其妙的有问题）。OK，安装上xml2Json库，很快我们就可以得到了Json串，然后Json转字典。OK我们就可以直接用KVC的方式把pageId和title给拿出来。然后把数据添加到Alfred的FeedBack之中。<br>OK，我们想要的数据就出来的。</p><h2 id="优化"><a href="#优化" class="headerlink" title="优化"></a>优化</h2><p>受限于公司Confluence的渣渣访问速度，只能针对于搜索条数和访问空间进行限制。<br>设置完之后的访问速度大概是1.5S左右，达到了个人理想的访问速度，还是比较能够接受的。</p>]]></content>
<summary type="html">
<h2 id="起因"><a href="#起因" class="headerlink" title="起因"></a>起因</h2><p>Confluence对于企业来说是一个非常有用的文档管理工具，但是每次我在使用的时候，我都要去进行一遍文档空间的目录查找。<br>虽然提供了搜索功能，但是搜索的延时，使用便捷度，都存在一定的问题。（哦，对了我们的Confluence是比较低版本的，太老了，一次搜索50条）<br>那么，想了一下如何去解决这个问题呢，Mac中万能的Alfred Workflow就是用来解决一系列的工作效率的问题的。<br>所以我在尝试能不能用Alfred Workflow来进行文档标题的搜索。<br>OK做这个事情之前，先找下目前有没有已经存在的包拿来直接使用。<br>找到了这个<a href="https://github.com/skleinei/alfred-confluence" target="_blank" rel="noopener">Alfred Workflow</a>，但是按照他的设置却发现搜索不了结果。<br>
</summary>
</entry>
<entry>
<title>OC 疯人院 - 引用计数</title>
<link href="http://www.zhz.io/2018/05/05/OC-%E7%96%AF%E4%BA%BA%E9%99%A2-%E5%BC%95%E7%94%A8%E8%AE%A1%E6%95%B0/"/>
<id>http://www.zhz.io/2018/05/05/OC-疯人院-引用计数/</id>
<published>2018-05-05T07:08:33.000Z</published>
<updated>2018-05-05T07:12:52.845Z</updated>
<content type="html"><![CDATA[<h2 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h2><p>早在MRC时代，引用计数是由我们开发者自己控制的，但是到了ARC时代，编译器帮我们做了引用计数管理这一步。这边的描述，就是为了解密，引用计数是如何实现的。如果不知道什么是引用计数，请参考其他人的文章~</p><h2 id="前提"><a href="#前提" class="headerlink" title="前提"></a>前提</h2><p>本文的所有内容均已下述标准下进行的实验</p><ul><li><a href="https://github.com/RetVal/objc-runtime" target="_blank" rel="noopener">objc源码（可编译版本）,tag号为723版本</a></li><li><a href="https://github.com/nianran/objc-runtime/tree/Feature/translation" target="_blank" rel="noopener">个人实验的路径,包含部分Demo，以及源码注解，欢迎指教</a></li><li>Xcode Version 9.3 (9E145)</li><li>Hopper Disassembler v4</li><li>以模拟器为准的话是x86_64，不同架构会有区别</li><li>本次实验内容，不涉及指针优化（TaggedPointer）<a id="more"></a></li></ul><h2 id="ISA"><a href="#ISA" class="headerlink" title="ISA"></a>ISA</h2><p>在了解引用计数前，我们来回顾一下ISA的isa_t的结构体中部分内容<br><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div></pre></td><td class="code"><pre><div class="line">// 由于我们的实验是基于x86_64的这边就列举了x86_64的结构体</div><div class="line"> struct {</div><div class="line"> uintptr_t nonpointer : 1;</div><div class="line"> uintptr_t has_assoc : 1;</div><div class="line"> uintptr_t has_cxx_dtor : 1;</div><div class="line"> uintptr_t shiftcls : 44; // MACH_VM_MAX_ADDRESS 0x7fffffe00000</div><div class="line"> uintptr_t magic : 6;</div><div class="line"> uintptr_t weakly_referenced : 1;</div><div class="line"> uintptr_t deallocating : 1;</div><div class="line"> uintptr_t has_sidetable_rc : 1;</div><div class="line"> uintptr_t extra_rc : 8;</div><div class="line"># define RC_ONE (1ULL<<56)</div><div class="line"># define RC_HALF (1ULL<<7)</div><div class="line"> };</div></pre></td></tr></table></figure></p><p>其中，我们可以看到的是有两个字段，我们先来做一下简单的了解<em>extra_rc</em>和<em>has_sidetable_rc</em>,这两个变量就是用来存储引用计数的关键内容。<br><em>extra_rc</em> : 用8位来存储引用计数大小 ->256<br><em>has_sidetable_rc</em> : 如果<em>extra_rc</em>不够存储了，那么就会标记<em>has_sidetable_rc</em>为1，并且存储到另外一个Table表中</p><h2 id="retain"><a href="#retain" class="headerlink" title="retain"></a>retain</h2><h3 id="描述"><a href="#描述" class="headerlink" title="描述"></a>描述</h3><p>用于引用计数加1的操作的函数<br>retain函数内实际是调用rootRetain函数。</p><h3 id="代码"><a href="#代码" class="headerlink" title="代码"></a>代码</h3><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div><div class="line">42</div><div class="line">43</div><div class="line">44</div><div class="line">45</div><div class="line">46</div><div class="line">47</div><div class="line">48</div><div class="line">49</div><div class="line">50</div></pre></td><td class="code"><pre><div class="line">ALWAYS_INLINE <span class="keyword">id</span> </div><div class="line">objc_object::rootRetain(<span class="keyword">bool</span> tryRetain, <span class="keyword">bool</span> handleOverflow)</div><div class="line">{</div><div class="line"></div><div class="line"> <span class="keyword">bool</span> sideTableLocked = <span class="literal">false</span>;</div><div class="line"> <span class="keyword">bool</span> transcribeToSideTable = <span class="literal">false</span>;</div><div class="line"></div><div class="line"> isa_t oldisa;</div><div class="line"> isa_t newisa;</div><div class="line"></div><div class="line"> <span class="keyword">do</span> {</div><div class="line"> transcribeToSideTable = <span class="literal">false</span>;</div><div class="line"> oldisa = LoadExclusive(&isa.bits);</div><div class="line"> newisa = oldisa;</div><div class="line"> <span class="comment">// carry Flag</span></div><div class="line"> uintptr_t carry;</div><div class="line"> <span class="comment">// 先存储在extra_rc字段中</span></div><div class="line"> <span class="comment">// carry标识超过了256之后会存储在其他地方 并且extra_rc减半 返回carry 为1</span></div><div class="line"> <span class="comment">// 这个代码没找到源码，网址是别人的研究成果</span></div><div class="line"> <span class="comment">// https://www.jianshu.com/p/18c3e88dfbf1</span></div><div class="line"> newisa.bits = addc(newisa.bits, RC_ONE, <span class="number">0</span>, &carry); <span class="comment">// extra_rc++</span></div><div class="line"> <span class="keyword">if</span> (slowpath(carry)) {</div><div class="line"> <span class="comment">// newisa.extra_rc++ overflowed</span></div><div class="line"> <span class="keyword">if</span> (!handleOverflow) {</div><div class="line"> ClearExclusive(&isa.bits);</div><div class="line"> <span class="comment">// carry为1的时候，重新进入rootRetain函数，进入SideTable的加入</span></div><div class="line"> <span class="keyword">return</span> rootRetain_overflow(tryRetain);</div><div class="line"> }</div><div class="line"> <span class="keyword">if</span> (!tryRetain && !sideTableLocked) sidetable_lock();</div><div class="line"> sideTableLocked = <span class="literal">true</span>;</div><div class="line"> transcribeToSideTable = <span class="literal">true</span>;</div><div class="line"> newisa.extra_rc = RC_HALF;</div><div class="line"> newisa.has_sidetable_rc = <span class="literal">true</span>;</div><div class="line"> }</div><div class="line"> <span class="comment">// 存储新的bits进入isa</span></div><div class="line"> } <span class="keyword">while</span> (slowpath(!StoreExclusive(&isa.bits, oldisa.bits, newisa.bits)));</div><div class="line"></div><div class="line"> <span class="keyword">if</span> (slowpath(transcribeToSideTable)) {</div><div class="line"> <span class="comment">// 存储一半的容量到SideTable中，x86下即为128</span></div><div class="line"> sidetable_addExtraRC_nolock(RC_HALF);</div><div class="line"> }</div><div class="line"></div><div class="line"> <span class="keyword">if</span> (slowpath(!tryRetain && sideTableLocked)) sidetable_unlock();</div><div class="line"> <span class="keyword">return</span> (<span class="keyword">id</span>)<span class="keyword">this</span>;</div><div class="line">}</div><div class="line">NEVER_INLINE <span class="keyword">id</span> </div><div class="line">objc_object::rootRetain_overflow(<span class="keyword">bool</span> tryRetain)</div><div class="line">{</div><div class="line"> <span class="keyword">return</span> rootRetain(tryRetain, <span class="literal">true</span>);</div><div class="line">}</div></pre></td></tr></table></figure><h3 id="代码-1"><a href="#代码-1" class="headerlink" title="代码"></a>代码</h3><p>有点长~简化成流程图，放到这边了，代码就不贴了。</p><h3 id="流程图"><a href="#流程图" class="headerlink" title="流程图"></a>流程图</h3><p><img src="/resources/C8D636CA6528A23616F47E330C0BE509.png" alt="retain.png"></p><blockquote><p>流程图为了方便区分，分了两条线。</p></blockquote><h3 id="总结"><a href="#总结" class="headerlink" title="总结"></a>总结</h3><ul><li>总的来说<em>extra_rc</em>和<em>has_sidetable_rc</em>加上SideTable来控制引用计数的</li><li><em>extra_rc</em>存储量比较小的计数标识，溢出则移出一部分交由另外两个值</li><li><em>has_sidetable_rc</em>只是标识是否有SideTable的存在，具体溢出的值还是存储在SideTable中的</li><li><em>SideTable</em>，用来存储溢出的引用计数的Map的，当然他还有其他作用，这边就只说明这个</li></ul><blockquote><p>系统是允许重写retain/release这些函数的，并且在调用真正的rootRetain之前会判断有没有实现自定义的retain函数<br>SideTable的具体实现部分没有具体源码就不深究了。每个对象都有自己的SideTable是独立的，只要了解至此我觉得已经够了</p></blockquote><h2 id="release"><a href="#release" class="headerlink" title="release"></a>release</h2><h3 id="描述-1"><a href="#描述-1" class="headerlink" title="描述"></a>描述</h3><p>用于引用计数减1的函数，当引用计数真正为0的时候，则调用真正的Release</p><h3 id="流程图-1"><a href="#流程图-1" class="headerlink" title="流程图"></a>流程图</h3><p><img src="/resources/32AEF7ED85A3955A807C73BAB2D37C72.png" alt="release.png"></p><h3 id="总结-1"><a href="#总结-1" class="headerlink" title="总结"></a>总结</h3><ul><li>引用计数先从<em>extra_rc</em>中进行减1操作</li><li>如果<em>extra_rc</em>为0，那么检查<em>SideTable</em>，如果<em>SideTable</em>中有数值，则取出<em>extra_rc</em>容量一半的数值，存入<em>extra_rc</em>，再做减法</li><li>当<em>extra_rc</em>和<em>SideTable</em>的引用计数都为0的时候，利用<em>msgSend</em>函数进行真正的dealloc函数的调用</li></ul><h2 id="引用计数总结"><a href="#引用计数总结" class="headerlink" title="引用计数总结"></a>引用计数总结</h2><p>引用计数的本质就是一个属性的加减以及一个Table的存储，并没有什么比较高深的东西。只当了解即可~</p>]]></content>
<summary type="html">
<h2 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h2><p>早在MRC时代，引用计数是由我们开发者自己控制的，但是到了ARC时代，编译器帮我们做了引用计数管理这一步。这边的描述，就是为了解密，引用计数是如何实现的。如果不知道什么是引用计数，请参考其他人的文章~</p>
<h2 id="前提"><a href="#前提" class="headerlink" title="前提"></a>前提</h2><p>本文的所有内容均已下述标准下进行的实验</p>
<ul>
<li><a href="https://github.com/RetVal/objc-runtime" target="_blank" rel="noopener">objc源码（可编译版本）,tag号为723版本</a></li>
<li><a href="https://github.com/nianran/objc-runtime/tree/Feature/translation" target="_blank" rel="noopener">个人实验的路径,包含部分Demo，以及源码注解，欢迎指教</a></li>
<li>Xcode Version 9.3 (9E145)</li>
<li>Hopper Disassembler v4</li>
<li>以模拟器为准的话是x86_64，不同架构会有区别</li>
<li>本次实验内容，不涉及指针优化（TaggedPointer）
</summary>
<category term="OC 疯人院" scheme="http://www.zhz.io/tags/OC-%E7%96%AF%E4%BA%BA%E9%99%A2/"/>
</entry>
<entry>
<title>OC 疯人院 - Autorelease</title>
<link href="http://www.zhz.io/2018/05/05/OC-%E7%96%AF%E4%BA%BA%E9%99%A2-Autorelease/"/>
<id>http://www.zhz.io/2018/05/05/OC-疯人院-Autorelease/</id>
<published>2018-05-05T07:07:16.000Z</published>
<updated>2018-05-08T09:59:30.761Z</updated>
<content type="html"><![CDATA[<h2 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h2><p>Autorelease->苹果在内存管理方面的优化策略，旨在方便开发者更加良好的管理对象的内存空间，做到OC对象无需开发者手动进行释放操作。<br>其是在OC从MRC转变为ARC中间形成的产物。</p><h2 id="前提"><a href="#前提" class="headerlink" title="前提"></a>前提</h2><p>本文的所有内容均已下述标准下进行的实验</p><ul><li><a href="https://github.com/RetVal/objc-runtime" target="_blank" rel="noopener">objc源码（可编译版本）,tag号为723版本</a></li><li><a href="https://github.com/nianran/objc-runtime/tree/Feature/translation" target="_blank" rel="noopener">个人实验的路径,包含部分Demo，以及源码注解，欢迎指教</a></li><li>Xcode Version 9.3 (9E145)</li><li>Hopper Disassembler v4</li></ul><h2 id="从最熟悉的地方开始"><a href="#从最熟悉的地方开始" class="headerlink" title="从最熟悉的地方开始"></a>从最熟悉的地方开始</h2><p>main函数，敲过代码的都知道，很多语言都是从main函数开始的（写个Hello,world!,哈哈哈）<br>OK，那么我们从main函数开始，下面贴的就是main函数在编译前和编译后（反编译出来）的对比<br><a id="more"></a><br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 原代码</span></div><div class="line"><span class="keyword">int</span> main(<span class="keyword">int</span> argc, <span class="keyword">const</span> <span class="keyword">char</span> * argv[]) {</div><div class="line"> <span class="keyword">@autoreleasepool</span> {</div><div class="line"> testRetainCount();</div><div class="line"> }</div><div class="line"> <span class="keyword">return</span> <span class="number">0</span>;</div><div class="line">}</div><div class="line"><span class="comment">// Hopper 反编译后的代码</span></div><div class="line"><span class="keyword">int</span> _main(<span class="keyword">int</span> arg0, <span class="keyword">int</span> arg1) {</div><div class="line"> <span class="keyword">void</span> *context = objc_autoreleasePoolPush();</div><div class="line"> _testRetainCount();</div><div class="line"> objc_autoreleasePoolPop(context);</div><div class="line"> <span class="keyword">return</span> <span class="number">0</span>;</div><div class="line">}</div></pre></td></tr></table></figure></p><p>从中，我们可以看到@autoreleasepool{}这个东西实质上是被替换成了以前以后的两个函数</p><ul><li>objc_autoreleasePoolPush()</li><li>objc_autoreleasePoolPop(void *)<br>OK，在讲这两个函数之前，我们有必要先了解一下这么一个类AutoreleasePoolPage</li></ul><h2 id="AutoreleasePoolPage"><a href="#AutoreleasePoolPage" class="headerlink" title="AutoreleasePoolPage"></a>AutoreleasePoolPage</h2><h3 id="AutoreleasePoolPage类的简介"><a href="#AutoreleasePoolPage类的简介" class="headerlink" title="AutoreleasePoolPage类的简介"></a>AutoreleasePoolPage类的简介</h3><p>AutoreleasePoolPage(自动释放池页？这个翻译好奇怪，我们这边就约定为释放页/page吧)。<br>那么这个东西是什么呢，它其实是用来管理需要自动释放对象的一个<a href="https://zh.wikipedia.org/zh-hans/%E5%8F%8C%E5%90%91%E9%93%BE%E8%A1%A8" target="_blank" rel="noopener">双向链表</a><br>OK,我们盗个图，嘻嘻<a href="https://blog.sunnyxx.com/2014/10/15/behind-autorelease/" target="_blank" rel="noopener">来源</a><br><img src="http://ww2.sinaimg.cn/mw690/51530583gw1elj2ugt21wj20f109m3zl.jpg" alt="AutoreleasePoolPage类"><br>简单介绍一下元素</p><ul><li>next:作为一个游标，用来指定下一个会被添加进来的对象的起始地址</li><li>thread:当前page所在的线程（page和线程是一一对应的关系）</li><li>child/parent:双向链表的福字节点，没什么好说明的。</li><li>Size:一个page被宏定义的SIZE限制在了4096字节，所以超过4K的话，就会创建新的childpage来存储</li><li>depth:链表深度，根链表为0，后续持续+1</li></ul><p>OK，看完了图，我们来看下AutoreleasePoolPage的构造函数<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 构造函数</span></div><div class="line">AutoreleasePoolPage(AutoreleasePoolPage *newParent) </div><div class="line"> : magic(), next(begin()), thread(pthread_self()),</div><div class="line"> parent(newParent), child(<span class="literal">nil</span>), </div><div class="line"> depth(parent ? <span class="number">1</span>+parent->depth : <span class="number">0</span>), </div><div class="line"> hiwat(parent ? parent->hiwat : <span class="number">0</span>)</div><div class="line">{ </div><div class="line"> <span class="keyword">if</span> (parent) {</div><div class="line"> parent->check();</div><div class="line"> assert(!parent->child);</div><div class="line"> parent->unprotect();</div><div class="line"> parent->child = <span class="keyword">this</span>;</div><div class="line"> parent->protect();</div><div class="line"> }</div><div class="line"> protect();</div><div class="line">}</div><div class="line"><span class="comment">// begin函数</span></div><div class="line"><span class="keyword">id</span> * begin() {</div><div class="line"> <span class="keyword">return</span> (<span class="keyword">id</span> *) ((uint8_t *)<span class="keyword">this</span>+<span class="keyword">sizeof</span>(*<span class="keyword">this</span>));</div><div class="line">}</div></pre></td></tr></table></figure></p><blockquote><p>Note: 在C++中，冒号后面是赋值，next(begin())就是next=begin()</p></blockquote><p> 最后，在内存中的表现就会如下图所示,<a href="https://blog.sunnyxx.com/2014/10/15/behind-autorelease/" target="_blank" rel="noopener">来源</a><br><img src="http://ww2.sinaimg.cn/mw690/51530583gw1elj5gvphtqj20dy0cx756.jpg" alt="AutoreleasePoolPage内存中的表现形式"><br>结合代码和上图，我们可以知道，新的page的next指针被指向begin的位置（实例内存之后）</p><h3 id="hotPage"><a href="#hotPage" class="headerlink" title="hotPage()"></a>hotPage()</h3><p>什么是hotPage呢？<br>hotPage就是当前内存中最活跃的那一页,被用来存储当前线程快速存储的对象的时候使用的。<br>获取的方式TLS（Thread Local Storage），这块并不懂，也不想深究，简单明了的理解就是一个全局表，用key来换取value，value就是当前的活跃页。<br>如有兴趣了解TLS参考<a href="https://blog.sunnyxx.com/2014/10/15/behind-autorelease/" target="_blank" rel="noopener">大神博客</a></p><h2 id="对象是何时被加入到page中的呢？"><a href="#对象是何时被加入到page中的呢？" class="headerlink" title="对象是何时被加入到page中的呢？"></a>对象是何时被加入到page中的呢？</h2><h3 id="实验"><a href="#实验" class="headerlink" title="实验"></a>实验</h3><p>在开始讲对象是怎么被加入页中，我们从一个实验中来看<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div></pre></td><td class="code"><pre><div class="line"></div><div class="line"><span class="keyword">void</span> * -[Person person](<span class="keyword">void</span> * <span class="keyword">self</span>, <span class="keyword">void</span> * _cmd) {</div><div class="line"> var_18 = [[Person alloc] init];</div><div class="line"> var_28 = [var_18 <span class="keyword">retain</span>];</div><div class="line"> objc_storeStrong(var_18, <span class="number">0x0</span>);</div><div class="line"> rax = [var_28 autorelease];</div><div class="line"> <span class="keyword">return</span> rax;</div><div class="line">}</div><div class="line"></div><div class="line">- (Person *)person {</div><div class="line"> Person *person = [[Person alloc] init];</div><div class="line"> <span class="keyword">return</span> person;</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">void</span> -[Person person1](<span class="keyword">void</span> * <span class="keyword">self</span>, <span class="keyword">void</span> * _cmd) {</div><div class="line"> rdi = var_18;</div><div class="line"> [[Person alloc] init];</div><div class="line"> objc_storeStrong(rdi, <span class="number">0x0</span>);</div><div class="line"> <span class="keyword">return</span>;</div><div class="line">}</div><div class="line">- (<span class="keyword">void</span>)person1 {</div><div class="line"> Person *person = [[Person alloc] init];</div><div class="line">}</div></pre></td></tr></table></figure></p><h3 id="解释"><a href="#解释" class="headerlink" title="解释"></a>解释</h3><p>对比两个函数person和person1函数，从反编译器的代码中我们可以看出来，对于没有超出作用于范围函数的对象，是不会被加入到autoReleasePool中的，但是如果会超出了函数作用于范围的值，那么编译器会帮助你主动加上autoRelease这个函数的。<br>那么我们来看一下autoRelease的函数调用关系</p><ul><li>[self autorelease]<ul><li>((id)self)->rootAutorelease();<ul><li>rootAutorelease2();<ul><li>AutoreleasePoolPage::autorelease((id)this); // this就是oc中的self<ul><li>autoreleaseFast(obj) // obj就是传入的self<ul><li>page->add(obj)<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">static</span> <span class="keyword">inline</span> <span class="keyword">id</span> *autoreleaseFast(<span class="keyword">id</span> obj)</div><div class="line">{</div><div class="line"> <span class="comment">// 线程安全的，找到当前页</span></div><div class="line"> <span class="comment">// hotPage:以全局的key(static pthread_key_t const key = AUTORELEASE_POOL_KEY;)存储的一份实例，动态更新双向页链表中最后一个节点</span></div><div class="line"> <span class="comment">// 都是同一个套路</span></div><div class="line"> <span class="comment">// 1. 存在页 跳转3</span></div><div class="line"> <span class="comment">// 2. 不存在页 创建页 跳转5</span></div><div class="line"> <span class="comment">// 3. 页是否满了 跳转5</span></div><div class="line"> <span class="comment">// 4. 添加obj 跳转6</span></div><div class="line"> <span class="comment">// 5. 设置hotPage 跳转4</span></div><div class="line"> <span class="comment">// 6. 结束</span></div><div class="line"> AutoreleasePoolPage *page = hotPage(); <span class="comment">// 找到当前活跃的PoolPage</span></div><div class="line"> <span class="keyword">if</span> (page && !page->full()) {</div><div class="line"> <span class="comment">// 存在页, 未满 -> 添加</span></div><div class="line"> <span class="keyword">return</span> page->add(obj);</div><div class="line"> } <span class="keyword">else</span> <span class="keyword">if</span> (page) {</div><div class="line"> <span class="comment">// 存在页, 已满 -> 新建后添加</span></div><div class="line"> <span class="keyword">return</span> autoreleaseFullPage(obj, page);</div><div class="line"> } <span class="keyword">else</span> {</div><div class="line"> <span class="comment">// 不存在页 -> 新建页后添加</span></div><div class="line"> <span class="keyword">return</span> autoreleaseNoPage(obj);</div><div class="line"> }</div><div class="line">}</div></pre></td></tr></table></figure></li></ul></li></ul></li></ul></li></ul></li></ul></li></ul><p>其实add操作就是将obj的指针加入page的next的位置，然后next位置上移<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">id</span> *add(<span class="keyword">id</span> obj)</div><div class="line">{</div><div class="line"> assert(!full());</div><div class="line"> unprotect();</div><div class="line"> <span class="keyword">id</span> *ret = next; <span class="comment">// faster than `return next-1` because of aliasing</span></div><div class="line"> *next++ = obj;</div><div class="line"> protect();</div><div class="line"> <span class="keyword">return</span> ret;</div><div class="line">}</div></pre></td></tr></table></figure></p><blockquote><p>objc_storeStrong增加引用计数的时候使用，但是这边是成员变量，并不会引起引用计数的增加</p></blockquote><h2 id="对象又是什么时候被释放的呢？"><a href="#对象又是什么时候被释放的呢？" class="headerlink" title="对象又是什么时候被释放的呢？"></a>对象又是什么时候被释放的呢？</h2><p>至此，我们已经了解到了，对象是如何被加入到page中的，接下来，我们要了解，对象的释放时机</p><h3 id="释放"><a href="#释放" class="headerlink" title="释放"></a>释放</h3><p>OK，那么我们回到文中最开始的那两个函数<br>objc_autoreleasePoolPush()<br>objc_autoreleasePoolPop(content)<br>每次调用objc_autoreleasePoolPush其实都是在给hotPage的栈顶添加一个哨兵对象，值为0，那么就会变成这个样子<br>（继续盗图<a href="https://blog.sunnyxx.com/2014/10/15/behind-autorelease/" target="_blank" rel="noopener">来源</a>）<br><img src="http://ww2.sinaimg.cn/large/51530583gw1elj5z7hawej20ji0dewff.jpg" alt="哨兵对象"><br>那么<em>objc_autoreleasePoolPush()</em>的返回值就是这个哨兵对象的地址，后续可以成为<em>objc_autoreleasePoolPop</em>的入参进行使用,于是乎就有如下结论</p><ul><li>根据传入的哨兵对象地址，找到对应的page页</li><li>根据page页和哨兵地址，将在哨兵对象添加时间后的对象全部调用release函数，并重置next指针</li></ul><h3 id="autoRelease和runloop的关系"><a href="#autoRelease和runloop的关系" class="headerlink" title="autoRelease和runloop的关系"></a>autoRelease和runloop的关系</h3><p>这块儿没有仔细的研究，抄一抄别人写的描述,<a href="https://blog.csdn.net/u011619283/article/details/53783650" target="_blank" rel="noopener">来源</a><br>我们总是看到有文章说程序启动后，苹果在主线程 RunLoop 里注册了两个 Observer：<br>第一个 Observer 监视的事件是 Entry(即将进入Loop)，其回调内会调用 _objc_autoreleasePoolPush() 创建自动释放池。其 order 是-2147483647，优先级最高，保证创建释放池发生在其他所有回调之前。<br>第二个 Observer 监视了两个事件： BeforeWaiting(准备进入睡眠) 和 Exit(即将退出Loop)，<br>BeforeWaiting(准备进入睡眠)时调用_objc_autoreleasePoolPop() 和 _objc_autoreleasePoolPush() 释放旧的池并创建新池；<br>Exit(即将退出Loop) 时调用 _objc_autoreleasePoolPop() 来释放自动释放池。这个 Observer 的 order 是 2147483647，优先级最低，保证其释放池子发生在其他所有回调之后。<br>打印出MainRunLoop，可以看到MainRunLoop的 Common mode Items 中就有这两个观察者<br><img src="/resources/D35DF794164F53C79121DA4C53C3CA27.jpg" alt="IMAGE"></p><h2 id="杂项"><a href="#杂项" class="headerlink" title="杂项"></a>杂项</h2><p>保证线程访问安全？<br><a href="https://blog.csdn.net/roland_sun/article/details/33728955" target="_blank" rel="noopener">Linux中mprotect()函数的用法</a><br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">protect();</div><div class="line">unprotect();</div></pre></td></tr></table></figure></p><p>objc_storeStrong的研究<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">void</span> objc_storeStrong(<span class="keyword">id</span> *location, <span class="keyword">id</span> obj)</div><div class="line">{</div><div class="line"> <span class="keyword">id</span> prev = *location;</div><div class="line"> <span class="keyword">if</span> (obj == prev) {</div><div class="line"> <span class="keyword">return</span>;</div><div class="line"> }</div><div class="line"> objc_retain(obj);</div><div class="line"> *location = obj;</div><div class="line"> objc_release(prev);</div><div class="line">}</div><div class="line"><span class="comment">// 真正的set方法，是不会直接return掉的</span></div><div class="line">objc_storeStrong(<span class="number">0x0</span>, rax);</div><div class="line"></div><div class="line"><span class="comment">// 临时变量，会直接在内部return掉</span></div><div class="line">objc_storeStrong(var_8, <span class="number">0x0</span>);</div></pre></td></tr></table></figure></p><h2 id="参考链接"><a href="#参考链接" class="headerlink" title="参考链接"></a>参考链接</h2><ol><li><a href="http://blog.sunnyxx.com/2014/10/15/behind-autorelease/" target="_blank" rel="noopener">黑幕背后的Autorelease</a></li><li><a href="https://blog.csdn.net/u011619283/article/details/53783650" target="_blank" rel="noopener">RunLoop总结：RunLoop 与GCD 、Autorelease Pool之间的关系</a></li></ol><!--定义-->]]></content>
<summary type="html">
<h2 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h2><p>Autorelease-&gt;苹果在内存管理方面的优化策略，旨在方便开发者更加良好的管理对象的内存空间，做到OC对象无需开发者手动进行释放操作。<br>其是在OC从MRC转变为ARC中间形成的产物。</p>
<h2 id="前提"><a href="#前提" class="headerlink" title="前提"></a>前提</h2><p>本文的所有内容均已下述标准下进行的实验</p>
<ul>
<li><a href="https://github.com/RetVal/objc-runtime" target="_blank" rel="noopener">objc源码（可编译版本）,tag号为723版本</a></li>
<li><a href="https://github.com/nianran/objc-runtime/tree/Feature/translation" target="_blank" rel="noopener">个人实验的路径,包含部分Demo，以及源码注解，欢迎指教</a></li>
<li>Xcode Version 9.3 (9E145)</li>
<li>Hopper Disassembler v4</li>
</ul>
<h2 id="从最熟悉的地方开始"><a href="#从最熟悉的地方开始" class="headerlink" title="从最熟悉的地方开始"></a>从最熟悉的地方开始</h2><p>main函数，敲过代码的都知道，很多语言都是从main函数开始的（写个Hello,world!,哈哈哈）<br>OK，那么我们从main函数开始，下面贴的就是main函数在编译前和编译后（反编译出来）的对比<br>
</summary>
<category term="OC 疯人院" scheme="http://www.zhz.io/tags/OC-%E7%96%AF%E4%BA%BA%E9%99%A2/"/>
</entry>
<entry>
<title>OC 疯人院 - ISA</title>
<link href="http://www.zhz.io/2018/05/05/OC-%E7%96%AF%E4%BA%BA%E9%99%A2-ISA/"/>
<id>http://www.zhz.io/2018/05/05/OC-疯人院-ISA/</id>
<published>2018-05-05T07:06:17.000Z</published>
<updated>2018-05-05T07:09:43.149Z</updated>
<content type="html"><![CDATA[<h2 id="介绍ISA"><a href="#介绍ISA" class="headerlink" title="介绍ISA"></a>介绍ISA</h2><p>Emmm,这个写到吐了，都不知道看第几遍Or写第几遍了，以前公司分享的，不能搬出来。<br>大家直接看大神的博客就可以了，后面的一些，我慢慢写，哈哈哈。<br><a href="https://github.com/Draveness/analyze/blob/master/contents/objc/%E4%BB%8E%20NSObject%20%E7%9A%84%E5%88%9D%E5%A7%8B%E5%8C%96%E4%BA%86%E8%A7%A3%20isa.md" target="_blank" rel="noopener">链接</a><br><a id="more"></a></p>]]></content>
<summary type="html">
<h2 id="介绍ISA"><a href="#介绍ISA" class="headerlink" title="介绍ISA"></a>介绍ISA</h2><p>Emmm,这个写到吐了，都不知道看第几遍Or写第几遍了，以前公司分享的，不能搬出来。<br>大家直接看大神的博客就可以了，后面的一些，我慢慢写，哈哈哈。<br><a href="https://github.com/Draveness/analyze/blob/master/contents/objc/%E4%BB%8E%20NSObject%20%E7%9A%84%E5%88%9D%E5%A7%8B%E5%8C%96%E4%BA%86%E8%A7%A3%20isa.md" target="_blank" rel="noopener">链接</a><br>
</summary>
<category term="OC 疯人院" scheme="http://www.zhz.io/tags/OC-%E7%96%AF%E4%BA%BA%E9%99%A2/"/>
</entry>
<entry>
<title>2017傻瓜式总结</title>
<link href="http://www.zhz.io/2018/01/06/2017%E5%82%BB%E7%93%9C%E5%BC%8F%E6%80%BB%E7%BB%93/"/>
<id>http://www.zhz.io/2018/01/06/2017傻瓜式总结/</id>
<published>2018-01-06T07:54:09.000Z</published>
<updated>2018-02-11T09:58:09.000Z</updated>
<content type="html"><![CDATA[<h1 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h1><p>OK~工作一年了哈，博客一直没有管，组内事情太多（借口，太懒），虽然写了一堆的文章，但是基本上都是在组内发布了。对外么，部分受限于公司协议之类的，部分是暂时觉得水平有限（反正也没什么人看么）。</p><h2 id="回顾2016年立的Flag-amp-Bad"><a href="#回顾2016年立的Flag-amp-Bad" class="headerlink" title="回顾2016年立的Flag & Bad"></a>回顾2016年立的Flag & Bad</h2><ul><li>明确自己的人生目标<br>在这一点上，应该考虑了很久才对，但是一直没有给自己一个明确的答案。<br>但是应该有了一系列的目标。<ol><li>财务自由？不不不，精神自由。在40岁以后能够达到精神自由，不再受限于生活中的种种因素的干扰。毕竟精神自由取决于个人，我觉得我是一个比较感性的人，钱虽然是越多越好，但是钱么，我觉得够用就好。过上舒舒服服的小日子。但是在此之前就必须要好好努力才可以</li><li>在技术上有所突破，为后来人留下一些真正有用的东西，再者是提高一些知名度。2018，一个月至少一篇以上有含量的技术分享，为之努力吧，也只能这么说一说了。</li></ol></li><li>去一次日本<br>没去，其他地方倒是去了好几个，对我个人来说也是很棒的体验。</li><li>能够从容的应对各种事情<br>在这个方面，我觉得个人做的还可以，练就了’Pocker Face’，只不过还有待加强心理承受能力吧，主要还是靠这个，心理承受能力好了才行。不然应对一些事情的时候，会不知所措。</li></ul><a id="more"></a><h2 id="无痕埋点-amp-AOP"><a href="#无痕埋点-amp-AOP" class="headerlink" title="无痕埋点 & AOP"></a>无痕埋点 & AOP</h2><p>做好了，但是产品没有启用（怪我咯？）。17年年初的时候，一直都在做这方面的事情，研究各种大公司的方案，终于耗时3个月的修修整整，出了一个完整的方案，但是埋点组说维护成本太大了（项目启动时候，已经明确提出说维护成本会很大，大致分支成本出处，与最后一致。）。哎，不说这些伤心事，虽然没有启用，但是对于我个人而言还是有很大的收获的，例如AOP相关把Aspects完全给弄完了一遍，梳理了行业内的所有无痕埋点的方案。基本每个方案都进行了一个尝试，留下了很多产物，对于自己有了一个很大的帮助。从中的Aspects库后来改了改，也用到了AOP埋点上，也算是有所收获吧。</p><h2 id="组件化静态库切换"><a href="#组件化静态库切换" class="headerlink" title="组件化静态库切换"></a>组件化静态库切换</h2><p>由于组内的调整，原先的组件化静态库切换方案也逐渐开始有了一些变化，从原先的利用’s.prepare_command’命令，到现在的利用:http/:git的切换。利用Cocoapods的Config单例也达到了清理缓存的功能，达到业务人员无感知的情况下清理缓存，从而进行切换工作，但是这个方案可能会局限于tag的情况，在其他分支下的情况可能会有所不同。应该会需要另外的一些调整。毕竟现在做的静态库的SHA校验也没有做。</p><p>盘点一下已经做好的功能</p><ul><li>源码和静态库完全独立管理（后期如果没有源码权限的同学访问，会直接指向静态库）</li><li>podspec无需配置任何东西，一切都在上传tag版本的时候进行需要绑定</li><li>使用s.source替换原先的s.prepare_command的下载方式，让使用上更加原生pod化</li><li>做了一个Ruby Gem专门来打包静态库（原先的Shell被废弃掉了，不好维护）</li><li>打包好的静态库暴露出特殊源文件（哇这个遇到了好多坑，比如说dummny文件，日乐购）</li><li>完整的子项目打包静态库分包</li><li>异步打包静态库，达到单机子多个Runner在跑也不会出问题。（目标是多机子）</li></ul><p>盘点一下2018年组件化静态库切换要做的</p><ul><li>ZIP文件的SHA校验（这个会对分支打包有帮助，但是还没完全研究）</li><li>打包系统监控（主要公司的gitlab一直不升级，拖慢了这个）</li><li>GEM提交代码后，自动化进行测试。（17年写脚本的时候，最痛苦的就是测试，一个个测试过去，手动的。。。。:-)）</li><li>分支打包静态库</li></ul><h2 id="投资方面"><a href="#投资方面" class="headerlink" title="投资方面"></a>投资方面</h2><p>emmm，说完了技术相关，来聊一聊投资相关吧，17年对于投资，有亏有赚。最主要的应该还是通过亏损和盈利调整好了心态。<br>16年的钱都在债券基金里面，17年基本都在51吧（保守型投资哈哈，保持年化8%左右哈哈。）。51因为有个朋友在，还是挺信任这家企业的。OK，这些事稳定的投资项目，期间我也稍微拿出几万在其他方面进行了尝试，起初大部分钱在债券基金的时候，有一部分的钱投入到了其他类型基金方向。因为不了解行情，瞎比乱投，导致后来亏损程度超过20%，股市基金深不可测，我决定暂时进行退出，多了解了解股市基金的规则之后再继续进入这个圈子内。<br>17年年末的时候，开始进入币圈。当时是10万左右软妹币的比特币。在local那边交易后，1.1万拿到了差不多0.1个左右的BTC，开始了我的抄币之旅。在经历多次买卖的亏损后，开始逐渐了解了市场行情，不贪就能获利，哈哈。顶峰的时候应该是到了1.6WRMB左右了吧。然后最近BTC开始疯狂大跌，调整了下心态。没有太多操作，放着就放着吧，我还是挺看好这一块的。虽然投的也不多。</p><h2 id="旅游"><a href="#旅游" class="headerlink" title="旅游"></a>旅游</h2><p>去了千岛湖、黄山、哈尔冰（2018年1月份去的，写总结之前去了，也算进去吧），虽然没有达到最开始去日本的目标，但是这几次行程对我来说都特别印象深刻。组织能力真的特别重要，还有适当的提前工作要做。你能想象220公里竟然需要开7个小时左右吗？他们那边的路不是按照100码来算的，有些地方是只能开到30码。瞬间就惊呆了。由于准备的不够充分，亚布力滑雪也没有去。这个倒是非常的遗憾吧。<br>精打细算。去旅游真的要精打细算，鲜明的栗子，我去哈尔冰4天花了3500。我的第一位朋友，哈尔滨/北京。7天的个人游，只花了4300。第二位朋友哈尔滨/漠河/北京，11天，5500，她跟我说她跟他老公的机票都是150块钱的，我瞬间惊呆了。</p><h3 id="对于2018年的展望"><a href="#对于2018年的展望" class="headerlink" title="对于2018年的展望"></a>对于2018年的展望</h3><p>2018，少立点FLAG吧，贵在坚持。</p><ul><li>坚持看书，看完12本书吧，一个月一本。</li><li>提升下英语水平。</li></ul><h2 id="最后"><a href="#最后" class="headerlink" title="最后"></a>最后</h2><p>NO PAINS, NO GAINS. Hello 2018.</p>]]></content>
<summary type="html">
<h1 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h1><p>OK~工作一年了哈，博客一直没有管，组内事情太多（借口，太懒），虽然写了一堆的文章，但是基本上都是在组内发布了。对外么，部分受限于公司协议之类的，部分是暂时觉得水平有限（反正也没什么人看么）。</p>
<h2 id="回顾2016年立的Flag-amp-Bad"><a href="#回顾2016年立的Flag-amp-Bad" class="headerlink" title="回顾2016年立的Flag &amp; Bad"></a>回顾2016年立的Flag &amp; Bad</h2><ul>
<li>明确自己的人生目标<br>在这一点上，应该考虑了很久才对，但是一直没有给自己一个明确的答案。<br>但是应该有了一系列的目标。<ol>
<li>财务自由？不不不，精神自由。在40岁以后能够达到精神自由，不再受限于生活中的种种因素的干扰。毕竟精神自由取决于个人，我觉得我是一个比较感性的人，钱虽然是越多越好，但是钱么，我觉得够用就好。过上舒舒服服的小日子。但是在此之前就必须要好好努力才可以</li>
<li>在技术上有所突破，为后来人留下一些真正有用的东西，再者是提高一些知名度。2018，一个月至少一篇以上有含量的技术分享，为之努力吧，也只能这么说一说了。</li>
</ol>
</li>
<li>去一次日本<br>没去，其他地方倒是去了好几个，对我个人来说也是很棒的体验。</li>
<li>能够从容的应对各种事情<br>在这个方面，我觉得个人做的还可以，练就了’Pocker Face’，只不过还有待加强心理承受能力吧，主要还是靠这个，心理承受能力好了才行。不然应对一些事情的时候，会不知所措。</li>
</ul>
</summary>
<category term="总结" scheme="http://www.zhz.io/tags/%E6%80%BB%E7%BB%93/"/>
</entry>
<entry>
<title>RN晴明视频学习笔记 - 第四章</title>
<link href="http://www.zhz.io/2017/10/11/%E6%99%B4%E6%98%8E%E8%A7%86%E9%A2%91%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-%E7%AC%AC%E5%9B%9B%E7%AB%A0/"/>
<id>http://www.zhz.io/2017/10/11/晴明视频学习笔记-第四章/</id>
<published>2017-10-11T02:29:14.000Z</published>
<updated>2018-02-12T02:30:14.005Z</updated>
<content type="html"><![CDATA[<h2 id="组件的生命周期"><a href="#组件的生命周期" class="headerlink" title="组件的生命周期"></a>组件的生命周期</h2><h3 id="详细的生命周期文档"><a href="#详细的生命周期文档" class="headerlink" title="详细的生命周期文档"></a>详细的生命周期文档</h3><p><a href="https://www.race604.com/react-native-component-lifecycle/" target="_blank" rel="noopener">博客</a></p><h3 id="其他Tips"><a href="#其他Tips" class="headerlink" title="其他Tips"></a>其他Tips</h3><ul><li>render中只做与渲染有关的操作，只读取、不修改任何数据（临时变量除外）<ul><li>因为界面的更改是经常的，所以render是经常触发的</li><li>所以如果你有修改数据等操作，就会多次触发，使结果难以预料</li><li>比如你执行setState，那么setState又触发render，就会导致死循环</li></ul></li><li>随组件加载只执行一次的操作，放在WillMount或者DidMount中<ul><li>比如远程取首页数据（fetch），比如弹出提示框</li></ul></li><li>记得在WillUnmount中销毁定时器和一些订阅事件</li><li>props发生变化，使用WillReceiveProps来处理（比如将变动同步给state）</li></ul><a id="more"></a><h2 id="组件之间的相互通信"><a href="#组件之间的相互通信" class="headerlink" title="组件之间的相互通信"></a>组件之间的相互通信</h2><h3 id="存在的情况"><a href="#存在的情况" class="headerlink" title="存在的情况"></a>存在的情况</h3><ol><li>父组件向子组件进行调用，传递</li><li>子组件之间的相互通信</li><li>子组件向父组件进行通信</li><li>全局跨任意组件间通信</li></ol><h3 id="父组件向子组件进行调用，传递-子组件之间的相互通信"><a href="#父组件向子组件进行调用，传递-子组件之间的相互通信" class="headerlink" title="父组件向子组件进行调用，传递/子组件之间的相互通信"></a>父组件向子组件进行调用，传递/子组件之间的相互通信</h3><ol><li>父组件将自身的state作为子组件的属性props进行传递，父组件调用setState,于是子组件的props相应变化</li><li>通过使用进行调用子组件的方法<figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 推荐写法</span></div><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">App</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> render() {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <CountDown ref={</div><div class="line"> instance => this.countDown = instance</div><div class="line"> } /></div><div class="line"> ) </div><div class="line"> }</div><div class="line"> componentDidMount() {</div><div class="line"> this.countDown.add(10086);</div><div class="line"> }</div><div class="line">}</div><div class="line">// 不推荐写法</div><div class="line">class App extends Component {</div><div class="line"> render() {</div><div class="line"> return (</div><div class="line"> <CountDown ref={</div><div class="line"> instance => this.countDown = instance</div><div class="line"> } /></div><div class="line"> ) </div><div class="line"> }</div><div class="line"> componentDidMount() {</div><div class="line"> this.countDown.add(10086);</div><div class="line"> }</div><div class="line">}</div></pre></td></tr></table></figure></li></ol><h3 id="子组件向父组件进行通信"><a href="#子组件向父组件进行通信" class="headerlink" title="子组件向父组件进行通信"></a>子组件向父组件进行通信</h3><ol><li>父组件将函数作为props传递给子组件，子组件在需要的时候进行调用，可以将数据作为函数参数进行回传<ul><li>类似于iOS中的block<figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div><div class="line">42</div><div class="line">43</div><div class="line">44</div><div class="line">45</div><div class="line">46</div><div class="line">47</div><div class="line">48</div><div class="line">49</div><div class="line">50</div><div class="line">51</div><div class="line">52</div><div class="line">53</div></pre></td><td class="code"><pre><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">CountDown</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> state = {</div><div class="line"> <span class="attr">count</span>: <span class="keyword">this</span>.props.time,</div><div class="line"> };</div><div class="line"> render() {</div><div class="line"> <span class="keyword">const</span> { count } = <span class="keyword">this</span>.state;</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <Text>{count}</Text></div><div class="line"> )</div><div class="line"> }</div><div class="line"> add = <span class="function">(<span class="params">time</span>) =></span> {</div><div class="line"> <span class="keyword">this</span>.setState({</div><div class="line"> <span class="attr">count</span>: <span class="keyword">this</span>.state.count + time</div><div class="line"> })</div><div class="line"> }</div><div class="line"> componentDidMount() {</div><div class="line"> <span class="keyword">this</span>.timer = setInterval(<span class="function"><span class="params">()</span> =></span> {</div><div class="line"> <span class="keyword">const</span> { count } = <span class="keyword">this</span>.state;</div><div class="line"> <span class="keyword">if</span> (count === <span class="number">0</span>) {</div><div class="line"> <span class="keyword">this</span>.props.timeout && <span class="keyword">this</span>.props.timeout( <span class="number">1</span> );</div><div class="line"> <span class="keyword">return</span> clearInterval(<span class="keyword">this</span>.timer);</div><div class="line"> }</div><div class="line"> <span class="keyword">this</span>.setState({</div><div class="line"> <span class="attr">count</span>: count - <span class="number">1</span>,</div><div class="line"> });</div><div class="line"> }, <span class="number">1000</span>);</div><div class="line"> }</div><div class="line"> componentWillUnmount() {</div><div class="line"> clearInterval(<span class="keyword">this</span>.timer);</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">App</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> addTime = <span class="function"><span class="params">()</span> =></span> {</div><div class="line"> <span class="keyword">this</span>.countDown.add(<span class="number">5</span>)</div><div class="line"> }</div><div class="line"> timeOut = <span class="function">(<span class="params">params</span>) =></span> {</div><div class="line"> alert(<span class="string">'爸爸知道了'</span> + params)</div><div class="line"> }</div><div class="line"> render() {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <View></div><div class="line"> <TouchableOpacity onPress={this.addTime}></div><div class="line"> 延长十秒</div><div class="line"> </TouchableOpacity></div><div class="line"> <CountDown ref={ countdown => this.countDown = countdown} time = '3' timeout={this.timeOut} /></div><div class="line"> </View></div><div class="line"> )</div><div class="line"> }</div><div class="line"></div><div class="line">}</div><div class="line"></div><div class="line">AppRegistry.registerComponent('App', () => App)</div></pre></td></tr></table></figure></li></ul></li></ol><blockquote><p>Note</p><ol><li>跟iOS一样如果一个传入的函数（iOS为Block），加上了括号，那么即会变成函数调用</li><li>根据1，在动态列表中，想传入对应参数就比较困难，所以有以下方法</li></ol></blockquote><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line">// 如何传入参数以区分不同的点击呢？</div><div class="line">arr.map(d => <Text key={d.id} onPress={this.handlePress}>{d.text}</Text>)</div><div class="line">// 错误使用，这么做会直接执行</div><div class="line">arr.map(d => <Text key={d.id} onPress={this.handlePress(d.id)}>{d.text}</Text>)</div><div class="line"></div><div class="line">// 正确使用</div><div class="line">arr.map(d => <Text key={d.id} onPress={() => this.handlePress(d.id)}>{d.text}</Text>)</div><div class="line">arr.map(d => <Text key={d.id} onPress={this.handlePress.bind(this, d.id)}>{d.text}</Text>)</div><div class="line">正确！箭头函数或bind都会生成新函数。传入参数以闭包的形式“封存”，留待调用。</div></pre></td></tr></table></figure><blockquote><p>这里有个坑，父类传到子类，因为函数被bind或者箭头函数重新进行了包装，所以在传参的时候，用在新的参数里面重新添加参数<br><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div><div class="line">42</div><div class="line">43</div><div class="line">44</div><div class="line">45</div><div class="line">46</div><div class="line">47</div><div class="line">48</div><div class="line">49</div><div class="line">50</div><div class="line">51</div><div class="line">52</div><div class="line">53</div><div class="line">54</div><div class="line">55</div><div class="line">56</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 实例代码</span></div><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">CountDown</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> state = {</div><div class="line"> <span class="attr">count</span>: <span class="keyword">this</span>.props.time,</div><div class="line"> };</div><div class="line"> render() {</div><div class="line"> <span class="keyword">const</span> { count } = <span class="keyword">this</span>.state;</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <Text>{count}</Text></div><div class="line"> )</div><div class="line"> }</div><div class="line"> add = <span class="function">(<span class="params">time</span>) =></span> {</div><div class="line"> <span class="keyword">this</span>.setState({</div><div class="line"> <span class="attr">count</span>: <span class="keyword">this</span>.state.count + time</div><div class="line"> })</div><div class="line"> }</div><div class="line"> componentDidMount() {</div><div class="line"> <span class="keyword">this</span>.timer = setInterval(<span class="function"><span class="params">()</span> =></span> {</div><div class="line"> <span class="keyword">const</span> { count } = <span class="keyword">this</span>.state;</div><div class="line"> <span class="keyword">if</span> (count === <span class="number">0</span>) {</div><div class="line"> <span class="keyword">this</span>.props.timeout && <span class="keyword">this</span>.props.timeout(<span class="string">"123"</span>);</div><div class="line"> <span class="keyword">return</span> clearInterval(<span class="keyword">this</span>.timer);</div><div class="line"> }</div><div class="line"> <span class="keyword">this</span>.setState({</div><div class="line"> <span class="attr">count</span>: count - <span class="number">1</span>,</div><div class="line"> });</div><div class="line"> }, <span class="number">1000</span>);</div><div class="line"> }</div><div class="line"> componentWillUnmount() {</div><div class="line"> clearInterval(<span class="keyword">this</span>.timer);</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">App</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> addTime = <span class="function"><span class="params">()</span> =></span> {</div><div class="line"> <span class="keyword">this</span>.countDown.add(<span class="number">5</span>)</div><div class="line"> }</div><div class="line"> timeOut = <span class="function">(<span class="params">params1,params2</span>) =></span> {</div><div class="line"> alert(<span class="string">'爸爸知道了'</span> + params1 + params2)</div><div class="line"> }</div><div class="line"> state = {</div><div class="line"> <span class="attr">arr</span>: [<span class="number">5</span>,<span class="number">4</span>,<span class="number">3</span>]</div><div class="line"> }</div><div class="line"> render() {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <View></div><div class="line"> {</div><div class="line"> this.state.arr.map (i => {</div><div class="line"> return <CountDown key={i} time={i} timeout={(child) => this.timeOut(i,child)}/></div><div class="line"> })</div><div class="line"> }</div><div class="line"> </View></div><div class="line"> )</div><div class="line"> }</div><div class="line">}</div><div class="line">AppRegistry.registerComponent('App', () => App)</div></pre></td></tr></table></figure></p></blockquote><h3 id="双向通信"><a href="#双向通信" class="headerlink" title="双向通信"></a>双向通信</h3><ol><li>全局时间订阅系统（EventEmitter）</li><li>（Flux系）单向数据流框架<ul><li>flux</li><li>reflux</li><li>alt</li><li>redux</li></ul></li><li>双向数据流狂阶<ul><li>mobx</li></ul></li></ol>]]></content>
<summary type="html">
<h2 id="组件的生命周期"><a href="#组件的生命周期" class="headerlink" title="组件的生命周期"></a>组件的生命周期</h2><h3 id="详细的生命周期文档"><a href="#详细的生命周期文档" class="headerlink" title="详细的生命周期文档"></a>详细的生命周期文档</h3><p><a href="https://www.race604.com/react-native-component-lifecycle/" target="_blank" rel="noopener">博客</a></p>
<h3 id="其他Tips"><a href="#其他Tips" class="headerlink" title="其他Tips"></a>其他Tips</h3><ul>
<li>render中只做与渲染有关的操作，只读取、不修改任何数据（临时变量除外）<ul>
<li>因为界面的更改是经常的，所以render是经常触发的</li>
<li>所以如果你有修改数据等操作，就会多次触发，使结果难以预料</li>
<li>比如你执行setState，那么setState又触发render，就会导致死循环</li>
</ul>
</li>
<li>随组件加载只执行一次的操作，放在WillMount或者DidMount中<ul>
<li>比如远程取首页数据（fetch），比如弹出提示框</li>
</ul>
</li>
<li>记得在WillUnmount中销毁定时器和一些订阅事件</li>
<li>props发生变化，使用WillReceiveProps来处理（比如将变动同步给state）</li>
</ul>
</summary>
<category term="RN" scheme="http://www.zhz.io/tags/RN/"/>
</entry>
<entry>
<title>RN晴明视频学习笔记 - 第三章</title>
<link href="http://www.zhz.io/2017/09/12/RN%E6%99%B4%E6%98%8E%E8%A7%86%E9%A2%91%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-%E7%AC%AC%E4%B8%89%E7%AB%A0/"/>
<id>http://www.zhz.io/2017/09/12/RN晴明视频学习笔记-第三章/</id>
<published>2017-09-12T02:24:25.000Z</published>
<updated>2018-02-12T02:27:45.983Z</updated>
<content type="html"><![CDATA[<h2 id="ReactJS和ReactNative"><a href="#ReactJS和ReactNative" class="headerlink" title="ReactJS和ReactNative"></a>ReactJS和ReactNative</h2><h3 id="两者区别比较"><a href="#两者区别比较" class="headerlink" title="两者区别比较"></a>两者区别比较</h3><p><img src="/resources/44D051F354FFBF35A300E1F8C731FD9B.jpg" alt="IMAGE"></p><ul><li>最重要的区别莫过于是控件方面的区别，对应的分别是对应平台的组件<a id="more"></a></li></ul><p><img src="/resources/DDDD7F748054B8B26D999CBAED87BAC7.jpg" alt="IMAGE"></p><ul><li>ReactNative提供转化的桥梁</li></ul><h3 id="规范-规则"><a href="#规范-规则" class="headerlink" title="规范/规则"></a>规范/规则</h3><p>借鉴与XHTML</p><ol><li>开始和结束标签配对<br><组件>ooxx</组件></li><li>无内容的组件标签应写为自封闭形式<br><组件></组件> 应写为 <组件 /></li><li><p>可自定义属性，字符串值应使用双引号，其他值用{}括起来</p><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><Person age={<span class="number">30</span>} sex=“male” married={<span class="literal">true</span>} /></div></pre></td></tr></table></figure></li><li><p>布尔属性可省略值</p><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><Person married /> 等价于 <Person married={<span class="literal">true</span>} /></div></pre></td></tr></table></figure></li><li><p>Render(渲染)必须是单一节点<br><img src="/resources/EF0E754011E0D0BED63225A48E19617B.jpg" alt="IMAGE"></p></li><li><p>空值会被自动忽略掉</p><figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div></pre></td><td class="code"><pre><div class="line"><div /> </div><div class="line"><div></div> </div><div class="line"><div>{false}</div> </div><div class="line"><div>{null}</div> </div><div class="line"><div>{undefined}</div> </div><div class="line"><div>{true}</div></div><div class="line"></div><div class="line">// 技巧 显示和隐藏组件</div><div class="line"><View></div><div class="line">{ showWarning && <Text>FBI warning</Text> }</div><div class="line"></View></div></pre></td></tr></table></figure></li><li><p>组件必须已大写开头<br><img src="/resources/A7778B71E3034ACDAB3F3FD994D0BE2A.jpg" alt="IMAGE"></p></li><li>文本必须写在Text的组件内<br><img src="/resources/B526EFC8D8E70CE825608A0B338F7B4C.jpg" alt="IMAGE"></li><li>注释的写法<br><img src="/resources/AC476BD3FECD7F5E58F30C30C56577CF.jpg" alt="IMAGE"></li><li>只能嵌入表达式<br><img src="/resources/EDB686DFCD64EBEB3E6378E6931F1049.jpg" alt="IMAGE"></li></ol><h2 id="初识React组件化开发"><a href="#初识React组件化开发" class="headerlink" title="初识React组件化开发"></a>初识React组件化开发</h2><h3 id="在线模拟器"><a href="#在线模拟器" class="headerlink" title="在线模拟器"></a>在线模拟器</h3><p><a href="http://dabbott.github.io/react-native-web-player/" target="_blank" rel="noopener">练习基础的模拟器</a></p><h3 id="示例一"><a href="#示例一" class="headerlink" title="示例一"></a>示例一</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div><div class="line">42</div><div class="line">43</div><div class="line">44</div><div class="line">45</div><div class="line">46</div><div class="line">47</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 导入开发所需要的库</span></div><div class="line"><span class="keyword">import</span> React, { Component } <span class="keyword">from</span> <span class="string">'react'</span></div><div class="line"><span class="keyword">import</span> {</div><div class="line"> AppRegistry,</div><div class="line"> StyleSheet,</div><div class="line"> Text,</div><div class="line"> View,</div><div class="line">} <span class="keyword">from</span> <span class="string">'react-native'</span></div><div class="line"></div><div class="line"><span class="comment">// Class类中会默认带有props，可以进行调用获取</span></div><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">GoodMorning</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> <span class="keyword">static</span> defaultProps = {</div><div class="line"> <span class="attr">name</span>: <span class="string">'somebody'</span></div><div class="line"> }</div><div class="line"> <span class="keyword">static</span> propTypes = {</div><div class="line"><span class="attr">name</span>: React.propTypes.string, <span class="comment">// 约定需要的类型（为字符串）</span></div><div class="line">}</div><div class="line"> render() {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <span class="comment">// 结构式语法</span></div><div class="line"> <Text>Good morning, {<span class="keyword">this</span>.props.name}!</Text></div><div class="line"> )</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line"><span class="comment">// Method中必须要手动去指定一下</span></div><div class="line"><span class="comment">// 如果的这里写了asd那么下面也要改成asd</span></div><div class="line"><span class="comment">// 如果这边有两个参数，默认是取第一个参数去取值</span></div><div class="line"><span class="keyword">const</span> GoodEvening = <span class="function">(<span class="params">props</span>) =></span> {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <Text>Good evening, {props.name}</Text></div><div class="line"> )</div><div class="line">}</div><div class="line"></div><div class="line"><span class="comment">// 生命一个组件 App是名字</span></div><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">App</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> render() {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <View></div><div class="line"> <GoodMorning name="Sir" /></div><div class="line"> <GoodEvening name="Madam" /></div><div class="line"> </View ></div><div class="line"> )</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line">AppRegistry.registerComponent('App', () => App)</div></pre></td></tr></table></figure><ul><li>属性使用小结<ul><li>在类中，属性为默认配置，不需要去写，</li><li>在方法中，属性要自己去声明,默认取第一个参数当做是属性的调用类</li><li>在使用属性的时候，必须加入大括号，才可以进行调用</li></ul></li><li>defaultProps 是用来设置属性的默认值的。</li><li>propTypes 是用来约束设置的属性的类型的，这个只在开发阶段有效，发布阶段会被自动移除</li></ul><h3 id="变量作用于"><a href="#变量作用于" class="headerlink" title="变量作用于"></a>变量作用于</h3><ul><li>函数内的局部变量，只能函数内读写，函数运行完后销毁（闭包除外）</li><li>class内的成员变量，在单个class的实例内读写，实例销毁时一并销毁<ul><li>使用时不要忘记this.</li></ul></li><li>class内的静态成员变量，在所有class的实例内共享，不会自动销毁<ul><li>其他模块可通过此class访问（类public）</li></ul></li><li>class外的变量，在所有class的实例内共享（公有），不会自动销毁<ul><li>除非明确export，否则其他模块不可访问（类private）</li></ul></li><li>global全局变量，任何地方可读写（类浏览器的window），不会自动销毁<ul><li>global.test = 1;则之后的任何地方可alert(global.test)或alert(test)</li></ul></li></ul><h3 id="各种变量的写法"><a href="#各种变量的写法" class="headerlink" title="各种变量的写法"></a>各种变量的写法</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div></pre></td><td class="code"><pre><div class="line">global.d = <span class="number">0</span>;<span class="comment">// 全局变量</span></div><div class="line"><span class="keyword">const</span> c = [<span class="number">1</span>,<span class="number">2</span>,<span class="number">3</span>];<span class="comment">// 在当前文件都可以访问</span></div><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">GoodMorning</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> </div><div class="line"> <span class="comment">// 成员变量</span></div><div class="line"> <span class="comment">// 推荐写法</span></div><div class="line"> a = <span class="number">1</span> <span class="comment">// 成员变量写法，注意没有var或者let</span></div><div class="line"> </div><div class="line"> <span class="comment">// 并不推荐的写法</span></div><div class="line"> <span class="keyword">constructor</span>(props) { <span class="comment">// 构造函数</span></div><div class="line"><span class="keyword">super</span>(props); <span class="comment">// 照抄即可，不可省略</span></div><div class="line"><span class="keyword">this</span>.a = <span class="number">1</span>; </div><div class="line">}</div><div class="line"></div><div class="line"> <span class="comment">// 静态变量 可以直接通过类名来访问，GoodMorning.defaultProps</span></div><div class="line"> <span class="keyword">static</span> b = <span class="number">2</span>;</div><div class="line"> render() {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <Text>Good morning, {this.props.name}!</Text></div><div class="line"> )</div><div class="line"> }</div><div class="line"> method1(){</div><div class="line"> <span class="comment">// 因为是实例的成员变量，所有加入this才可以使用</span></div><div class="line"> <span class="keyword">this</span>.a;</div><div class="line"> }</div><div class="line">}</div></pre></td></tr></table></figure><h3 id="示例二，使用map进行列表的循环创建"><a href="#示例二，使用map进行列表的循环创建" class="headerlink" title="示例二，使用map进行列表的循环创建"></a>示例二，使用map进行列表的循环创建</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">import</span> React, { Component } <span class="keyword">from</span> <span class="string">'react'</span></div><div class="line"><span class="keyword">import</span> {</div><div class="line"> AppRegistry,</div><div class="line"> StyleSheet,</div><div class="line"> Text,</div><div class="line"> View,</div><div class="line">} <span class="keyword">from</span> <span class="string">'react-native'</span></div><div class="line"></div><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">GoodMorning</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> render() {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <Text>Good morning, {this.props.name}!</Text></div><div class="line"> )</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">const</span> names = [<span class="string">'name1'</span>, <span class="string">'name2'</span>, <span class="string">'name3'</span>,<span class="string">'name4'</span>]</div><div class="line"><span class="keyword">const</span> GoodEvening = <span class="function">(<span class="params">props</span>) =></span> {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <Text>Good evening, {props.name}</Text></div><div class="line"> )</div><div class="line">}</div><div class="line"></div><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">App</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> render() {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <View></div><div class="line"> {</div><div class="line"> // 因为虚拟DOM的需要比较差异，使用key方便DOM进行差异的比较，key直接放在直接容器上面</div><div class="line"> names.map(name => <GoodMorning key={name} name={name} />)</div><div class="line"> </div><div class="line"> }</div><div class="line"> </View ></div><div class="line"> )</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line">AppRegistry.registerComponent('App', () => App)</div></pre></td></tr></table></figure><h3 id="示例三，点赞示例"><a href="#示例三，点赞示例" class="headerlink" title="示例三，点赞示例"></a>示例三，点赞示例</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div><div class="line">42</div><div class="line">43</div><div class="line">44</div><div class="line">45</div><div class="line">46</div><div class="line">47</div><div class="line">48</div><div class="line">49</div><div class="line">50</div><div class="line">51</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">import</span> React, { Component } <span class="keyword">from</span> <span class="string">'react'</span></div><div class="line"><span class="keyword">import</span> {</div><div class="line"> AppRegistry,</div><div class="line"> StyleSheet,</div><div class="line"> Text,</div><div class="line"> View,</div><div class="line"> Image,</div><div class="line"> TouchableOpacity,</div><div class="line">} <span class="keyword">from</span> <span class="string">'react-native'</span></div><div class="line"></div><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">App</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> state = {</div><div class="line"> <span class="attr">likes</span>: <span class="number">0</span>,</div><div class="line"> };</div><div class="line"> onPress = <span class="function"><span class="params">()</span> =></span> {</div><div class="line"> <span class="keyword">const</span> { likes } = <span class="keyword">this</span>.state;</div><div class="line"> <span class="keyword">this</span>.setState({</div><div class="line"> <span class="attr">likes</span>: likes + <span class="number">1</span>,</div><div class="line"> });</div><div class="line"> };</div><div class="line"> render() {</div><div class="line"> <span class="keyword">return</span> (</div><div class="line"> <View style={styles.container}></div><div class="line"> <TouchableOpacity onPress={this.onPress}></div><div class="line"> <Image</div><div class="line"> style={styles.image}</div><div class="line"> source={{</div><div class="line"> uri: 'https://github.com/facebook/react-native/blob/master/Examples/UIExplorer/js/Thumbnails/like.png?raw=true',</div><div class="line"> }}</div><div class="line"> /></div><div class="line"> </TouchableOpacity></div><div class="line"> <Text>{this.state.likes}</Text></div><div class="line"> </View></div><div class="line"> )</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line">const styles = StyleSheet.create({</div><div class="line"> container: {</div><div class="line"> flex: 1,</div><div class="line"> justifyContent: 'center',</div><div class="line"> alignItems: 'center',</div><div class="line"> backgroundColor: '#F5FCFF',</div><div class="line"> },</div><div class="line"> image: {</div><div class="line"> width: 65,</div><div class="line"> height: 65,</div><div class="line"> },</div><div class="line">})</div><div class="line"></div><div class="line">AppRegistry.registerComponent('App', () => App)</div></pre></td></tr></table></figure><p>总结</p><ul><li>一切界面的变化都是因为state变化而引起的</li><li>但是state的修改必须通过setState进行修改</li><li>直接通过修改属性值是无效的，例如this.state.likes = 100;这样的直接赋值修改是无效的</li><li>setState是一个merge合并操作，只修改指定的属性，不影响其他属性</li><li><p>setState是一个异步操作，修改之后并不能马上修改生效。</p><ul><li>比如说在setState之后马上运行alert，进行数字的显示，这个时候是错的<figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 错误示例</span></div><div class="line">onPress = <span class="function"><span class="params">()</span> =></span> {</div><div class="line"> <span class="keyword">const</span> { likes } = <span class="keyword">this</span>.state;</div><div class="line"> <span class="keyword">this</span>.setState({</div><div class="line"> <span class="attr">likes</span>: likes + <span class="number">1</span>,</div><div class="line"> });</div><div class="line"> alert(<span class="keyword">this</span>.state.like);</div><div class="line">};</div></pre></td></tr></table></figure></li></ul><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 正确示例</span></div><div class="line">onPress = <span class="function"><span class="params">()</span> =></span> {</div><div class="line"> <span class="keyword">const</span> { likes } = <span class="keyword">this</span>.state;</div><div class="line"> <span class="keyword">const</span> newLikes = likes + <span class="number">1</span>;</div><div class="line"> <span class="keyword">this</span>.setState({</div><div class="line"> <span class="attr">likes</span>: newLikes,</div><div class="line"> });</div><div class="line"> alert(newLikes);</div><div class="line">};</div></pre></td></tr></table></figure></li></ul><h3 id="为什么要引入State的概念"><a href="#为什么要引入State的概念" class="headerlink" title="为什么要引入State的概念"></a>为什么要引入State的概念</h3><p><img src="/resources/9F302D689DC97C4B7A739579EFE09BCA.jpg" alt="IMAGE"><br>如图所示，虚拟DOM的修改只是一个增量更新，比较得出前和后的差异，计算出diff，然后去重新渲染差异部分<br><img src="/resources/E105DA6EEC89A567AC63D8E805575EB1.jpg" alt="IMAGE"><br><img src="/resources/361B31527F3ECE475B3705A81659E72C.jpg" alt="IMAGE"><br>Key的使用方便了DOM计算出差异部分，对差异部分可以进行更方便的比较。</p><h2 id="参考链接"><a href="#参考链接" class="headerlink" title="参考链接"></a>参考链接</h2><h3 id="JSX"><a href="#JSX" class="headerlink" title="JSX"></a>JSX</h3><p><a href="https://facebook.github.io/react/docs/introducing-jsx.html" target="_blank" rel="noopener">Introducint JSX</a><br><a href="https://facebook.github.io/react/docs/jsx-in-depth.html" target="_blank" rel="noopener">JSX In Depth</a></p>]]></content>
<summary type="html">
<h2 id="ReactJS和ReactNative"><a href="#ReactJS和ReactNative" class="headerlink" title="ReactJS和ReactNative"></a>ReactJS和ReactNative</h2><h3 id="两者区别比较"><a href="#两者区别比较" class="headerlink" title="两者区别比较"></a>两者区别比较</h3><p><img src="/resources/44D051F354FFBF35A300E1F8C731FD9B.jpg" alt="IMAGE"></p>
<ul>
<li>最重要的区别莫过于是控件方面的区别，对应的分别是对应平台的组件
</summary>
<category term="RN" scheme="http://www.zhz.io/tags/RN/"/>
</entry>
<entry>
<title>RN晴明视频学习笔记 - 第二章</title>
<link href="http://www.zhz.io/2017/09/10/%E6%99%B4%E6%98%8E%E8%A7%86%E9%A2%91%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-%E7%AC%AC%E4%BA%8C%E7%AB%A0/"/>
<id>http://www.zhz.io/2017/09/10/晴明视频学习笔记-第二章/</id>
<published>2017-09-10T08:51:50.000Z</published>
<updated>2018-02-12T02:28:16.000Z</updated>
<content type="html"><![CDATA[<h2 id="原生-Hybird-RN"><a href="#原生-Hybird-RN" class="headerlink" title="原生/Hybird/RN"></a>原生/Hybird/RN</h2><h3 id="对比"><a href="#对比" class="headerlink" title="对比"></a>对比</h3><table><thead><tr><th>形式</th><th>介绍</th><th>优势</th><th>劣势</th></tr></thead><tbody><tr><td>原生</td><td>使用原生语言进行编写开发</td><td>性能好/有生态圈的优势点</td><td>各个平台有各自的语言，学习成本大，不兼容</td></tr><tr><td>Hybrid App混合开发</td><td>使用前段代码，在各个平台上有他的容器WebView，利用他进行渲染</td><td>跨平台，适合简单应用</td><td>性能不是很好 </td></tr><tr><td>RN</td><td>较于前面两者之间，使用JS开发，翻译成原生组件进行展示</td><td>学习成本低，天然跨平台，无审核热更新，具有优秀的社区能力（开源库）</td><td>性能</td><td></td></tr></tbody></table><h2 id="ECMAScript"><a href="#ECMAScript" class="headerlink" title="ECMAScript"></a>ECMAScript</h2><p>名词解释：ECMAScript是一种由Ecma国际（前身为欧洲计算机制造商协会,英文名称是European Computer Manufacturers Association）通过ECMA-262标准化的脚本程序设计语言。这种语言在万维网上应用广泛，它往往被称为JavaScript或JScript，但实际上后两者是ECMA-262标准的实现和扩展。</p><p>简单的说：ECMAScript是一种标准文本语法，JS是根据其进行设计的</p><a id="more"></a><h3 id="变量和常量生命"><a href="#变量和常量生命" class="headerlink" title="变量和常量生命"></a>变量和常量生命</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">let</span> greeting = <span class="string">'hi'</span>; <span class="comment">// 新式写法，推荐使用</span></div><div class="line"><span class="keyword">var</span> greeting1 = <span class="string">'hi1'</span>; <span class="comment">//老式写法，不推荐使用</span></div><div class="line"><span class="keyword">const</span> answer = <span class="number">4</span>;</div><div class="line"><span class="comment">// 多个生命简单些发</span></div><div class="line"><span class="keyword">let</span> a = <span class="string">'1'</span>; b = <span class="string">'2'</span>;</div><div class="line"><span class="comment">// 没有声明或者声明后没有赋值的变量值为常量</span></div></pre></td></tr></table></figure><h3 id="箭头函数"><a href="#箭头函数" class="headerlink" title="箭头函数"></a>箭头函数</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">(a,b) => a+b;</div></pre></td></tr></table></figure><ul><li><p>class外部：</p><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">let</span> 函数名 = <span class="function">(<span class="params">参数</span>) =></span> { 内部逻辑 };</div></pre></td></tr></table></figure></li><li><p>class内部：</p><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line"><span class="class"><span class="keyword">class</span> <span class="title">SomeComponent</span> <span class="keyword">extends</span> <span class="title">Component</span> </span>{</div><div class="line"> 方法名 = <span class="function">(<span class="params">参数</span>) =></span> {</div><div class="line"> <span class="comment">// 内部逻辑</span></div><div class="line"> };</div><div class="line">}</div></pre></td></tr></table></figure></li></ul><blockquote><p>可能并不是很习惯这种写法，联想方案<br>f(x) = πx^2<br>(x) => 3.14 <em> x </em> x<br>输入 => 输出<br>参数 => 返回表达式</p></blockquote><ul><li>Tips:这里有个坑，如果箭头函数的代码块部分使用了大括号，则此时切莫忘了使用return语句返回：</li><li>() => 1 // 返回1</li><li>() => { 1 } // 返回 undefined</li><li>() => { return 1; } // 返回1</li></ul><h3 id="扩展运算符"><a href="#扩展运算符" class="headerlink" title="扩展运算符"></a>扩展运算符</h3><p>…扩展运算符好比是把一个压缩包给解压到当前目录<br><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 数组</span></div><div class="line"> <span class="comment">// 数组</span></div><div class="line"> <span class="keyword">let</span> a = [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>]</div><div class="line"> <span class="built_in">console</span>.log(...a) <span class="comment">// 1 2 3 </span></div><div class="line"> <span class="built_in">console</span>.log(<span class="number">1</span>, ...a, <span class="number">5</span>) <span class="comment">// 1 1 2 3 5</span></div><div class="line"></div><div class="line"> <span class="comment">// 对象</span></div><div class="line"> <span class="keyword">let</span> z = { <span class="attr">a</span>: <span class="number">3</span>, <span class="attr">b</span>: <span class="number">4</span> }; </div><div class="line"> <span class="keyword">let</span> n = { ...z }; </div><div class="line"> <span class="built_in">console</span>.log(n)<span class="comment">// { a: 3, b: 4 }</span></div></pre></td></tr></table></figure></p><h3 id="解构"><a href="#解构" class="headerlink" title="解构"></a>解构</h3><p>可以想象成一个语法糖，可以帮助你快速的从对象中获取数据<br><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 数组</span></div><div class="line"><span class="keyword">let</span> [a, b, c] = [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>];</div><div class="line"><span class="built_in">console</span>.log(a, b, c); <span class="comment">// 1 2 3</span></div><div class="line"></div><div class="line"><span class="comment">// 对象</span></div><div class="line"><span class="keyword">var</span> props = { <span class="attr">checked</span>: <span class="literal">false</span>, <span class="attr">data</span>: { <span class="attr">count</span>: <span class="number">3</span>, <span class="attr">price</span>: <span class="number">100</span> } }; </div><div class="line"><span class="comment">// 从props中拿到checked的值和count值</span></div><div class="line"><span class="keyword">var</span> { checked, <span class="attr">data</span>: { count } } = props;</div><div class="line"><span class="built_in">console</span>.log(checked, count);<span class="comment">// false 3</span></div></pre></td></tr></table></figure></p><h3 id="数组的新增方法"><a href="#数组的新增方法" class="headerlink" title="数组的新增方法"></a>数组的新增方法</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 数组查找元素</span></div><div class="line">[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].includes(<span class="number">2</span>); <span class="comment">// true </span></div><div class="line">[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].includes(<span class="number">4</span>); <span class="comment">// false</span></div><div class="line"><span class="comment">// 字符串也可用</span></div><div class="line">‘hello’.includes(‘hell’);<span class="comment">// true</span></div><div class="line"></div><div class="line"><span class="comment">// map返回等长的新数组</span></div><div class="line"><span class="keyword">let</span> odds = [<span class="number">1</span>, <span class="number">3</span>, <span class="number">5</span>, <span class="number">7</span>, <span class="number">9</span>];</div><div class="line"><span class="keyword">let</span> evens = odds.map(<span class="function"><span class="params">i</span> =></span> i + <span class="number">1</span>); <span class="comment">// [2, 4, 6, 8, 10]</span></div><div class="line"></div><div class="line"><span class="comment">// 使用标记技巧</span></div><div class="line"><span class="keyword">let</span> names = [‘tom’, ‘jerry’];</div><div class="line"><span class="keyword">let</span> nameTags = names.map(<span class="function"><span class="params">n</span> =></span> <Text>{n}<<span class="regexp">/Text>)</span></div></pre></td></tr></table></figure><h3 id="推荐书籍"><a href="#推荐书籍" class="headerlink" title="推荐书籍"></a>推荐书籍</h3><ol><li><a href="https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Guide" target="_blank" rel="noopener">MDN（Mozilla开发者网络）</a></li><li><a href="http://es6.ruanyifeng.com/" target="_blank" rel="noopener">ECMAScript 6 入门（阮一峰）</a></li></ol><h2 id="Node-js"><a href="#Node-js" class="headerlink" title="Node.js"></a>Node.js</h2><h3 id="为什么RN需要Node-js"><a href="#为什么RN需要Node-js" class="headerlink" title="为什么RN需要Node.js"></a>为什么RN需要Node.js</h3><ol><li>提供React Packager的运行环境</li><li>提供npm包管理器来安装第三方模块 (node_modules)</li><li>提供一些可参考的代码规范（commonjs）</li></ol><h3 id="RN的基本架构"><a href="#RN的基本架构" class="headerlink" title="RN的基本架构"></a>RN的基本架构</h3><p><img src="/resources/A28F86AE1A1C71F1FC29711BAA78B8E0.jpg" alt="IMAGE"></p><h3 id="npm使用"><a href="#npm使用" class="headerlink" title="npm使用"></a>npm使用</h3><ol><li>npm依赖于同级目录下一个package.json文件进行，仓库的下载和依赖管理。没有这个文件可以使用npm init进行创建</li><li>npm install (npm i)包安装器<ul><li>附加命令 -g，安装在系统根目录中，比如说react-native-cli</li><li>–save/-S 查找仓库中某某库的方法下载，并且安装，填写进入package.json文件</li></ul></li><li>npm下载的库都会存放在同级目录下的node_modules文件夹中，此文件夹随用随装，原则上不复制、不移动、不修改、不上传</li></ol><h3 id="导入导出概念"><a href="#导入导出概念" class="headerlink" title="导入导出概念"></a>导入导出概念</h3><ol><li>JS本身没有模块的概念，他们之间是无法自由引用的。所以node.js制定了commonjs模块贵方，方便了拆分和引用代码<a href="https://nodejs.org/docs/latest/api/modules.html" target="_blank" rel="noopener">参考链接</a></li><li><p>提供两种引用的语法</p><ul><li><p>ES5 不推荐</p><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line"><span class="built_in">module</span>.exports = moduleA; <span class="comment">// a.js导出moduleA模块</span></div><div class="line"><span class="keyword">var</span> moduleA = <span class="built_in">require</span>(’./a’) <span class="comment">// 同级目录下的B模块导入moduleA模块</span></div></pre></td></tr></table></figure></li><li><p>ES6 推荐使用</p><figure class="highlight js"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">export</span> <span class="keyword">default</span> moduleA; <span class="comment">// a.js导出模块A</span></div><div class="line"><span class="keyword">import</span> moduleA <span class="keyword">from</span> ’./a’ <span class="comment">// b.js目录下导入同级目录的a.js文件的某个模块</span></div></pre></td></tr></table></figure></li></ul></li><li><p>模块查找/引用规则：</p><ul><li>require(‘ooxx’) – 引用node_modules/ooxx/index.js，或是node_modules/ooxx/package.json中main字段所指定的js文件</li><li>require(‘./a’) – 引用同目录下的a.js文件。注意 ./ 不能省略，.js后缀可写可不写</li><li>require(‘../a/b’) – 引用父目录中的a目录中的b.js文件；若b为目录名，则查找引用b目录中的index.js文件。</li></ul></li></ol><blockquote><p>npm仓库是需要翻墙的，可以使用国内的淘宝源,使用下述命令进行源的切换<br>npm config set registry <a href="https://registry.npm.taobao.org" target="_blank" rel="noopener">https://registry.npm.taobao.org</a> –global<br>npm config set disturl <a href="https://npm.taobao.org/dist" target="_blank" rel="noopener">https://npm.taobao.org/dist</a> –global</p></blockquote><h2 id="知识点储备"><a href="#知识点储备" class="headerlink" title="知识点储备"></a>知识点储备</h2><ol><li>所有的JS文件，都会被package打包整合进入main.jsbundle文件中。</li><li>main.jsbundle文件可以通过pushby/codepush（微软）进行发布后的热更新。</li></ol><h2 id="书籍网站推荐推荐"><a href="#书籍网站推荐推荐" class="headerlink" title="书籍网站推荐推荐"></a>书籍网站推荐推荐</h2><h3 id="JS相关"><a href="#JS相关" class="headerlink" title="JS相关"></a>JS相关</h3><ol><li>JavaScript 权威指南（第6版）</li><li>JavaScript 高级程序设计（第3版）</li><li>JavaScript 语言精粹</li></ol><blockquote><p>1和2为基础，二选一去看，3为使用技巧上的一些东西</p></blockquote>]]></content>
<summary type="html">
<h2 id="原生-Hybird-RN"><a href="#原生-Hybird-RN" class="headerlink" title="原生/Hybird/RN"></a>原生/Hybird/RN</h2><h3 id="对比"><a href="#对比" class="headerlink" title="对比"></a>对比</h3><table>
<thead>
<tr>
<th>形式</th>
<th>介绍</th>
<th>优势</th>
<th>劣势</th>
</tr>
</thead>
<tbody>
<tr>
<td>原生</td>
<td>使用原生语言进行编写开发</td>
<td>性能好/有生态圈的优势点</td>
<td>各个平台有各自的语言，学习成本大，不兼容</td>
</tr>
<tr>
<td>Hybrid App混合开发</td>
<td>使用前段代码，在各个平台上有他的容器WebView，利用他进行渲染</td>
<td>跨平台，适合简单应用</td>
<td>性能不是很好 </td>
</tr>
<tr>
<td>RN</td>
<td>较于前面两者之间，使用JS开发，翻译成原生组件进行展示</td>
<td>学习成本低，天然跨平台，无审核热更新，具有优秀的社区能力（开源库）</td>
<td>性能</td>
<td></td>
</tr>
</tbody>
</table>
<h2 id="ECMAScript"><a href="#ECMAScript" class="headerlink" title="ECMAScript"></a>ECMAScript</h2><p>名词解释：ECMAScript是一种由Ecma国际（前身为欧洲计算机制造商协会,英文名称是European Computer Manufacturers Association）通过ECMA-262标准化的脚本程序设计语言。这种语言在万维网上应用广泛，它往往被称为JavaScript或JScript，但实际上后两者是ECMA-262标准的实现和扩展。</p>
<p>简单的说：ECMAScript是一种标准文本语法，JS是根据其进行设计的</p>
</summary>
<category term="RN" scheme="http://www.zhz.io/tags/RN/"/>
</entry>
<entry>
<title>ReactiveCocoa - 信号类分析</title>
<link href="http://www.zhz.io/2017/08/18/ReactiveCocoa%E4%BF%A1%E5%8F%B7%E7%B1%BB%E5%88%86%E6%9E%90/"/>
<id>http://www.zhz.io/2017/08/18/ReactiveCocoa信号类分析/</id>
<published>2017-08-18T03:06:40.000Z</published>
<updated>2018-02-12T03:09:02.682Z</updated>
<content type="html"><![CDATA[<h2 id="信号类基础概念及原理"><a href="#信号类基础概念及原理" class="headerlink" title="信号类基础概念及原理"></a>信号类基础概念及原理</h2><h3 id="信号类的集成关系图"><a href="#信号类的集成关系图" class="headerlink" title="信号类的集成关系图"></a>信号类的集成关系图</h3><p><img src="/resources/FA1CDE683EA35A1CCDBAB883F9B0A64D.jpg" alt="IMAGE"></p><a id="more"></a><h3 id="RACSrteam"><a href="#RACSrteam" class="headerlink" title="RACSrteam"></a>RACSrteam</h3><ul><li>解释：所有信号的父类</li><li>作用：建立信号之间的链接，例如map/filter/zip函数</li><li>使用案例：一般情况下，我们不需要去创建它，直接创建会抛出异常。</li></ul><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 已Empty为例。</span></div><div class="line">+ (__kindof RACStream *)empty {</div><div class="line"><span class="built_in">NSString</span> *reason = [<span class="built_in">NSString</span> stringWithFormat:<span class="string">@"%@ must be overridden by subclasses"</span>, <span class="built_in">NSStringFromSelector</span>(_cmd)];</div><div class="line"><span class="keyword">@throw</span> [<span class="built_in">NSException</span> exceptionWithName:<span class="built_in">NSInternalInconsistencyException</span> reason:reason userInfo:<span class="literal">nil</span>];</div><div class="line">}</div></pre></td></tr></table></figure><h2 id="RACSignal"><a href="#RACSignal" class="headerlink" title="RACSignal"></a>RACSignal</h2><h3 id="综述"><a href="#综述" class="headerlink" title="综述"></a>综述</h3><p>RACEmptySignal/RACReturnSignal/RACErrorSignal/RACDynamicSignal都是对于RACSignal的补充，帮其完善已有的方法</p><h3 id="RACEmptySignal"><a href="#RACEmptySignal" class="headerlink" title="RACEmptySignal"></a>RACEmptySignal</h3><ul><li>解释：空信号，用来实现RACSignal的 +empty 方法</li><li>作用：在一些信号的创建的时候，不能返回nil，需要返回一个空信号</li><li>原理：在使用+[RACSignal empty]方法的时候，其内部转到了RACEmptySignal</li></ul><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div></pre></td><td class="code"><pre><div class="line"><span class="class"><span class="keyword">@implementation</span> <span class="title">RACSignal</span> (<span class="title">RACStream</span>)</span></div><div class="line">+ (RACSignal *)empty {</div><div class="line"><span class="keyword">return</span> [RACEmptySignal empty];</div><div class="line">}</div><div class="line"><span class="keyword">@end</span></div><div class="line"></div><div class="line"><span class="class"><span class="keyword">@implementation</span> <span class="title">RACEmptySignal</span></span></div><div class="line">+ (RACSignal *)empty {</div><div class="line"><span class="keyword">return</span> [[[<span class="keyword">self</span> alloc] init] setNameWithFormat:<span class="string">@"+empty"</span>];</div><div class="line">}</div><div class="line">- (RACDisposable *)subscribe:(<span class="keyword">id</span><RACSubscriber>)subscriber {</div><div class="line"><span class="built_in">NSCParameterAssert</span>(subscriber != <span class="literal">nil</span>);</div><div class="line"></div><div class="line"><span class="keyword">return</span> [RACScheduler.subscriptionScheduler schedule:^{</div><div class="line">[subscriber sendCompleted];</div><div class="line">}];</div><div class="line">}</div><div class="line"><span class="keyword">@end</span></div></pre></td></tr></table></figure><ul><li>使用案例：<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line">_buttonCommand = [[RACCommand alloc] initWithSignalBlock:^RACSignal * _Nonnull(<span class="keyword">id</span> _Nullable input) {</div><div class="line"> @strongify(<span class="keyword">self</span>);</div><div class="line"> RACSignal *signal = ...;</div><div class="line"> <span class="comment">// 根据条立案来创建信号</span></div><div class="line"> <span class="keyword">return</span> signal;</div><div class="line"> }];</div></pre></td></tr></table></figure></li></ul><blockquote><p>Note: 为了篇幅问题，上面的创建函数方法都被删减过，区别只在于DEBUG和REALSE情况下是够为单例，其他没有问题</p></blockquote><h3 id="RACReturnSignal"><a href="#RACReturnSignal" class="headerlink" title="RACReturnSignal"></a>RACReturnSignal</h3><ul><li>解释：一元信号，用来实现 RACSignal 的 +return: 方法；</li><li>作用：通常用于信号的转换操作，平常用的不多</li><li><p>原理：在使用+[RACSignal return:]方法的时候，其内部转到了RACReturnSignal</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div></pre></td><td class="code"><pre><div class="line">+ (RACSignal *)<span class="keyword">return</span>:(<span class="keyword">id</span>)value {</div><div class="line">RACReturnSignal *signal = [[<span class="keyword">self</span> alloc] init];</div><div class="line">signal->_value = value;</div><div class="line"><span class="keyword">return</span> signal;</div><div class="line">}</div><div class="line"></div><div class="line">- (RACDisposable *)subscribe:(<span class="keyword">id</span><RACSubscriber>)subscriber {</div><div class="line"> <span class="keyword">return</span> [RACScheduler.subscriptionScheduler schedule:^{</div><div class="line"> [subscriber sendNext:<span class="keyword">self</span>.value];</div><div class="line"> [subscriber sendCompleted];</div><div class="line"> }];</div><div class="line">}</div></pre></td></tr></table></figure></li><li><p>使用案例：</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div></pre></td><td class="code"><pre><div class="line">@weakify(<span class="keyword">self</span>);</div><div class="line"> [[[<span class="keyword">self</span>.tf_age rac_textSignal] flattenMap:^RACStream *(<span class="keyword">id</span> value) {</div><div class="line"> <span class="keyword">return</span> [RACReturnSignal <span class="keyword">return</span>:[<span class="built_in">NSString</span> stringWithFormat:<span class="string">@"年龄是:%@"</span>,value]];</div><div class="line"> }] subscribeNext:^(<span class="keyword">id</span> x) {</div><div class="line"> @strongify(<span class="keyword">self</span>);</div><div class="line"> <span class="keyword">self</span>.lb_age.text = x;</div><div class="line"> }];</div></pre></td></tr></table></figure></li></ul><h3 id="RACErrorSignal"><a href="#RACErrorSignal" class="headerlink" title="RACErrorSignal"></a>RACErrorSignal</h3><ul><li>解释：一元信号，用来实现 RACSignal 的 +error: 方法；</li><li>作用：通常用于订阅过程中发生的错误</li><li><p>原理：在使用+[RACSignal error:]方法的时候，其内部转到了RACErrorSignal</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div></pre></td><td class="code"><pre><div class="line">+ (RACSignal *)error:(<span class="built_in">NSError</span> *)error {</div><div class="line">RACErrorSignal *signal = [[<span class="keyword">self</span> alloc] init];</div><div class="line">signal->_error = error;</div><div class="line"><span class="keyword">return</span> signal;</div><div class="line">}</div><div class="line"><span class="comment">// 订阅者直接会收到Error信号</span></div><div class="line">- (RACDisposable *)subscribe:(<span class="keyword">id</span><RACSubscriber>)subscriber {</div><div class="line"> <span class="keyword">return</span> [RACScheduler.subscriptionScheduler schedule:^{</div><div class="line"> [subscriber sendError:<span class="keyword">self</span>.error];</div><div class="line"> }];</div><div class="line">}</div></pre></td></tr></table></figure></li><li><p>使用案例：</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line">+ (RACSignal *)userRegister:(<span class="built_in">NSString</span> *)loginId</div><div class="line"> authCode:(<span class="built_in">NSString</span> *)authCode</div><div class="line"> password:(<span class="built_in">NSString</span> *)password {</div><div class="line"> <span class="keyword">if</span> (![HZLoginModuleUtils checkPassword:password]) {</div><div class="line"> <span class="keyword">return</span> [RACSignal error:[<span class="built_in">NSError</span> errorWithDomain:<span class="string">@"HZLoginModule"</span></div><div class="line"> code:<span class="number">1</span></div><div class="line"> userInfo:@{<span class="string">@"message"</span>:<span class="string">@"密码格式"</span>}]];</div><div class="line"> }</div><div class="line"> <span class="comment">// balabalabala</span></div><div class="line">}</div></pre></td></tr></table></figure></li></ul><h3 id="RACDynamicSignal"><a href="#RACDynamicSignal" class="headerlink" title="RACDynamicSignal"></a>RACDynamicSignal</h3><ul><li>解释：动态信号，使用一个 block 来实现订阅行为，我们在使用 RACSignal 的 +createSignal: 方法时创建的就是该类的实例；</li><li>作用：每时每刻用的冷信号都是这么创建的</li><li>原理：<ol><li>在使用+[RACSignal createSignal:]方法的时候，其内部转到了RACDynamicSignal</li><li>RACDynamicSignal copy了一份Block</li><li>在RACDynamicSignal收到订阅的时候，通过RACPassthroughSubscriber包装订阅者和disposable将其进行包装</li><li>包装完成之后，建立Scheduler进行Block执行</li><li>提供dispose方法给外界，可以随时进行信号的销毁。注意这个dispose是复合的dispose不是你自己指定的了。<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div></pre></td><td class="code"><pre><div class="line">+ (RACSignal *)createSignal:(RACDisposable * (^)(<span class="keyword">id</span><RACSubscriber> subscriber))didSubscribe {</div><div class="line">RACDynamicSignal *signal = [[<span class="keyword">self</span> alloc] init];</div><div class="line">signal->_didSubscribe = [didSubscribe <span class="keyword">copy</span>];</div><div class="line"><span class="keyword">return</span> [signal setNameWithFormat:<span class="string">@"+createSignal:"</span>];</div><div class="line">}</div><div class="line"></div><div class="line">- (RACDisposable *)subscribe:(<span class="keyword">id</span><RACSubscriber>)subscriber {</div><div class="line"><span class="built_in">NSCParameterAssert</span>(subscriber != <span class="literal">nil</span>);</div><div class="line"> <span class="comment">// 这里有一个RACCompoundDisposable，这是一个RACDisposable，只不过RACCompoundDisposable可以存放多个RACDisposable 。当RACCompoundDisposable 执行dispose方法时，它所存放的disposable都会被释放。</span></div><div class="line">RACCompoundDisposable *disposable = [RACCompoundDisposable compoundDisposable];</div><div class="line"><span class="comment">// 订阅者每一次订阅信号是产生一个 Disposable ，并将其与此次订阅关联起来，通过装饰器 RACPassthroughSubscriber 来做到，装饰器的功能如下:</span></div><div class="line"><span class="comment">// - 包装真正的订阅者，使自己成为订阅者的替代者</span></div><div class="line"> <span class="comment">// - 将真正的订阅者与一个订阅时产生的 Disposable 关联起来。</span></div><div class="line">subscriber = [[RACPassthroughSubscriber alloc] initWithSubscriber:subscriber signal:<span class="keyword">self</span> disposable:disposable];</div><div class="line"></div><div class="line"><span class="keyword">if</span> (<span class="keyword">self</span>.didSubscribe != <span class="literal">NULL</span>) {</div><div class="line"> <span class="comment">// 将当前的运行转接到RACScheduler进行</span></div><div class="line">RACDisposable *schedulingDisposable = [RACScheduler.subscriptionScheduler schedule:^{</div><div class="line"> <span class="comment">// 调用真正的订阅，但是传递的并非之前的订阅者，而是装饰器</span></div><div class="line">RACDisposable *innerDisposable = <span class="keyword">self</span>.didSubscribe(subscriber);</div><div class="line">[disposable addDisposable:innerDisposable];</div><div class="line">}];</div><div class="line"></div><div class="line">[disposable addDisposable:schedulingDisposable];</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">return</span> disposable;</div><div class="line">}</div></pre></td></tr></table></figure></li></ol></li></ul><blockquote><p>Note:RACDynamicSignal 使用 RACPassthroughSubscriber ,订阅者装饰器直接伪装成真正的订阅器，传给 didSubscribe 这个 block 使用。在这个 block 中，会有一些事件发送给订阅者装饰器，而这个订阅者装饰器则根据 disposable 的状态来来决定是否转发给真正的订阅者。disposable 作为返回值，返回给外部，也就是说能够从外部来取消这个订阅了。</p></blockquote><ul><li>使用案例：<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line">RACSignal *aSignal = [RACSignal createSignal:^RACDisposable *(<span class="keyword">id</span><RACSubscriber> subscriber) {</div><div class="line"> <span class="comment">// 此处subscriber为转换后的subscriber</span></div><div class="line"> [subscriber sendNext:<span class="string">@"abc"</span>];</div><div class="line"> [subscriber sendCompleted];</div><div class="line"></div><div class="line"> <span class="keyword">return</span> [RACDisposable disposableWithBlock:^{</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"disposable"</span>);</div><div class="line"> }];</div><div class="line">}];</div></pre></td></tr></table></figure></li></ul><h3 id="RACChannelTerminal"><a href="#RACChannelTerminal" class="headerlink" title="RACChannelTerminal"></a>RACChannelTerminal</h3><p>我们先来看看双向绑定这件事情。<br><img src="/resources/41863AF8A61873D1D38D72BF3C38FC69.jpg" alt="IMAGE"><br>我们如何实现信号从A传到B，又可以从B传到A呢。利用信号的双向传递的话，我们可以用RACSubject，这样A发的信号B就能接到，而且B发的信号A也能够接收到。<br><img src="/resources/3333985DB5A5A590D5966CFDDFDC34A6.jpg" alt="IMAGE"><br>这样也有个问题，因为A是Subject的订阅者又是接受者，A发送给B的东西，A也同样会被接受到，这是我们不希望看到的。</p><ul><li>解释：为了解决数据双向传递，特别设计的一个类</li><li>作用：上面已经有描述不再说了</li><li>案例：<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 建立双向绑定方式1</span></div><div class="line">RACChannelTo(<span class="keyword">self</span>,string1) = RACChannelTo(<span class="keyword">self</span>,string2);</div><div class="line"><span class="comment">// 建立双向绑定方式2</span></div><div class="line"><span class="keyword">self</span>.channel1 = [[RACKVOChannel alloc] initWithTarget:<span class="keyword">self</span> keyPath:<span class="string">@"string1"</span> nilValue:<span class="literal">nil</span>];</div><div class="line"><span class="keyword">self</span>.channel2 = [[RACKVOChannel alloc] initWithTarget:<span class="keyword">self</span> keyPath:<span class="string">@"string2"</span> nilValue:<span class="literal">nil</span>];</div><div class="line"><span class="keyword">self</span>.channel1[<span class="string">@"followingTerminal"</span>] = <span class="keyword">self</span>.channel2[<span class="string">@"followingTerminal"</span>];</div></pre></td></tr></table></figure></li></ul><blockquote><p>方案2只是方案1的展开，我们平时用的都是RACKVOChannel。所以以此为例</p></blockquote><ul><li>订阅关系<br><img src="/resources/8053428106F17C5443DC8D72D019093C.jpg" alt="IMAGE"><br>特别解释：</li></ul><ol><li>lead中的value等于follow的other<br>3=7 4=6 10=12 11=13</li><li>同一个Terminal中的信号不会进行互相传递，因为使用ignoreValues进行了忽略(只是提及大可忽略这条规则)</li><li>string1和string2并不是真正的订阅者。这边只是为了显示方便给大家演示这么写了。<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div></pre></td><td class="code"><pre><div class="line"><span class="class"><span class="keyword">@implementation</span> <span class="title">RACChannel</span></span></div><div class="line"></div><div class="line">- (<span class="keyword">instancetype</span>)init {</div><div class="line"><span class="keyword">self</span> = [<span class="keyword">super</span> init];</div><div class="line"></div><div class="line">RACReplaySubject *leadingSubject = [[RACReplaySubject replaySubjectWithCapacity:<span class="number">0</span>] setNameWithFormat:<span class="string">@"leadingSubject"</span>];</div><div class="line">RACReplaySubject *followingSubject = [[RACReplaySubject replaySubjectWithCapacity:<span class="number">1</span>] setNameWithFormat:<span class="string">@"followingSubject"</span>];</div><div class="line"></div><div class="line">[[leadingSubject ignoreValues] subscribe:followingSubject];</div><div class="line">[[followingSubject ignoreValues] subscribe:leadingSubject];</div><div class="line"></div><div class="line"> <span class="comment">// 结合下面的Terminal初始化，即可看到leaf的value和follow的other是相等的</span></div><div class="line">_leadingTerminal = [[[RACChannelTerminal alloc] initWithValues:leadingSubject otherTerminal:followingSubject] setNameWithFormat:<span class="string">@"leadingTerminal"</span>];</div><div class="line">_followingTerminal = [[[RACChannelTerminal alloc] initWithValues:followingSubject otherTerminal:leadingSubject] setNameWithFormat:<span class="string">@"followingTerminal"</span>];</div><div class="line"></div><div class="line"><span class="keyword">return</span> <span class="keyword">self</span>;</div><div class="line">}</div><div class="line"><span class="keyword">@end</span></div><div class="line"></div><div class="line"><span class="class"><span class="keyword">@implementation</span> <span class="title">RACChannelTerminal</span></span></div><div class="line">- (<span class="keyword">instancetype</span>)initWithValues:(RACSignal *)values otherTerminal:(<span class="keyword">id</span><RACSubscriber>)otherTerminal {</div><div class="line"><span class="built_in">NSCParameterAssert</span>(values != <span class="literal">nil</span>);</div><div class="line"><span class="built_in">NSCParameterAssert</span>(otherTerminal != <span class="literal">nil</span>);</div><div class="line"> </div><div class="line"><span class="keyword">self</span> = [<span class="keyword">super</span> init];</div><div class="line"></div><div class="line">_values = values;</div><div class="line">_otherTerminal = otherTerminal;</div><div class="line"></div><div class="line"><span class="keyword">return</span> <span class="keyword">self</span>;</div><div class="line">}</div><div class="line"><span class="keyword">@end</span></div></pre></td></tr></table></figure></li></ol><ul><li>发送流程</li></ul><ol><li>String1开始发出了属性改变的信号。</li><li>由1.2.3这个value订阅者进行信号的接收</li><li>由于3=7，3又是热信号，收到信号后进行信号转发发送给13这个订阅者</li><li>由于13=11，11为热信号，收到信号后，发送给订阅者。执行setValue:ForKey:将值进行传递</li></ol><ul><li>看下代码<br>步骤1中的关键代码<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 这段是KVC注册属性变化之后的信号回调处理</span></div><div class="line">RACDisposable *observationDisposable = [strongTarget rac_observeKeyPath:keyPath options:<span class="built_in">NSKeyValueObservingOptionInitial</span> observer:<span class="literal">nil</span> block:^(<span class="keyword">id</span> value, <span class="built_in">NSDictionary</span> *change, <span class="built_in">BOOL</span> causedByDealloc, <span class="built_in">BOOL</span> affectedOnlyLastComponent) {</div><div class="line"><span class="keyword">if</span> (!causedByDealloc && affectedOnlyLastComponent && <span class="keyword">self</span>.currentThreadData.ignoreNextUpdate) {</div><div class="line">[<span class="keyword">self</span> destroyCurrentThreadData];</div><div class="line"><span class="keyword">return</span>;</div><div class="line">}</div><div class="line"> <span class="comment">// 交给了leadingTerminal进行信号转发</span></div><div class="line">[<span class="keyword">self</span>.leadingTerminal sendNext:value];</div><div class="line">}];</div></pre></td></tr></table></figure></li></ul><p>在Terminal中，我们可以看到其实terminal只是作为包装而已，真正发送和订阅时由value和other来进行订阅和发送的。<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div></pre></td><td class="code"><pre><div class="line">@implementation RACChannelTerminal</div><div class="line"></div><div class="line">#pragma mark Lifecycle</div><div class="line"></div><div class="line">- (instancetype)initWithValues:(RACSignal *)values otherTerminal:(id<RACSubscriber>)otherTerminal {</div><div class="line">NSCParameterAssert(values != nil);</div><div class="line">NSCParameterAssert(otherTerminal != nil);</div><div class="line"> </div><div class="line">self = [super init];</div><div class="line"></div><div class="line">_values = values;</div><div class="line">_otherTerminal = otherTerminal;</div><div class="line"></div><div class="line">return self;</div><div class="line">}</div><div class="line"></div><div class="line">#pragma mark RACSignal</div><div class="line"></div><div class="line">- (RACDisposable *)subscribe:(id<RACSubscriber>)subscriber {</div><div class="line">return [self.values subscribe:subscriber];</div><div class="line">}</div><div class="line"></div><div class="line">#pragma mark <RACSubscriber></div><div class="line"></div><div class="line">- (void)sendNext:(id)value {</div><div class="line">[self.otherTerminal sendNext:value];</div><div class="line">}</div><div class="line"></div><div class="line">- (void)sendError:(NSError *)error {</div><div class="line">[self.otherTerminal sendError:error];</div><div class="line">}</div><div class="line"></div><div class="line">- (void)sendCompleted {</div><div class="line">[self.otherTerminal sendCompleted];</div><div class="line">}</div><div class="line"></div><div class="line">- (void)didSubscribeWithDisposable:(RACCompoundDisposable *)disposable {</div><div class="line">[self.otherTerminal didSubscribeWithDisposable:disposable];</div><div class="line">}</div><div class="line"></div><div class="line">@end</div></pre></td></tr></table></figure></p><p>步骤4中的关键代码：<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div></pre></td><td class="code"><pre><div class="line">[[<span class="keyword">self</span>.leadingTerminal</div><div class="line">finally:^{</div><div class="line">[observationDisposable dispose];</div><div class="line">}]</div><div class="line">subscribeNext:^(<span class="keyword">id</span> x) {</div><div class="line"><span class="built_in">NSObject</span> *object = (keyPathComponentsCount > <span class="number">1</span> ? [<span class="keyword">self</span>.target valueForKeyPath:keyPathByDeletingLastKeyPathComponent] : <span class="keyword">self</span>.target);</div><div class="line"><span class="keyword">if</span> (object == <span class="literal">nil</span>) <span class="keyword">return</span>;</div><div class="line"></div><div class="line">[<span class="keyword">self</span> createCurrentThreadData];</div><div class="line"><span class="keyword">self</span>.currentThreadData.ignoreNextUpdate = <span class="literal">YES</span>;</div><div class="line"> <span class="comment">// 可以看到收到信号后，进行setValue:forKey:进行赋值</span></div><div class="line">[object setValue:x ?: nilValue forKey:lastKeyPathComponent];</div><div class="line">} error:^(<span class="built_in">NSError</span> *error) {</div><div class="line"><span class="built_in">NSCAssert</span>(<span class="literal">NO</span>, <span class="string">@"Received error in %@: %@"</span>, <span class="keyword">self</span>, error);</div><div class="line"></div><div class="line"><span class="comment">// Log the error if we're running with assertions disabled.</span></div><div class="line"><span class="built_in">NSLog</span>(<span class="string">@"Received error in %@: %@"</span>, <span class="keyword">self</span>, error);</div><div class="line">}];</div></pre></td></tr></table></figure></p><h2 id="热信号"><a href="#热信号" class="headerlink" title="热信号"></a>热信号</h2><h3 id="RACSubject"><a href="#RACSubject" class="headerlink" title="RACSubject"></a>RACSubject</h3><p>了解RACSubject先扯一扯热冷信号概念<br>冷信号:冷信号只会在被订阅时，向订阅者发送通知。<br>热信号:热信号会在任意时间发送出信号，向所有订阅者发送。<br>举个购买报纸的🌰<br>冷信号：你每次去杂货铺购买报纸，才会拿到报纸<br>热信号：你向报社订阅报纸，报社会主动每天早上给你发报纸，不管你要不要接受，都给你发送</p><p>区别之处冷信号会直接去发送订阅内容<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">- (RACDisposable *)subscribe:(<span class="keyword">id</span><RACSubscriber>)subscriber {</div><div class="line"><span class="keyword">self</span>.didSubscribe(subscriber);</div><div class="line">}</div></pre></td></tr></table></figure></p><p>而热信号并不会及时发送订阅内容，而是在推送数据的时候，遍历订阅人，进行数据的推送<br>盗一张图来用一下<a href="http://draveness.me/racsubject.html" target="_blank" rel="noopener">出处</a><br><img src="/resources/3D51143DC6F75B2AEE05C2D59C8CCFEA.jpg" alt="IMAGE"><br>订阅过程</p><ol><li>初始化一个装饰器</li><li>将订阅者加入当前订阅者数组内</li><li>创建disposable，在订阅者被销毁（指的是被dispose）的同时，将订阅者从订阅列表中进行移除<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div></pre></td><td class="code"><pre><div class="line">- (RACDisposable *)subscribe:(<span class="keyword">id</span><RACSubscriber>)subscriber {</div><div class="line">RACCompoundDisposable *disposable = [RACCompoundDisposable compoundDisposable];</div><div class="line">subscriber = [[RACPassthroughSubscriber alloc] initWithSubscriber:subscriber signal:<span class="keyword">self</span> disposable:disposable];</div><div class="line"></div><div class="line"><span class="built_in">NSMutableArray</span> *subscribers = <span class="keyword">self</span>.subscribers;</div><div class="line"><span class="keyword">@synchronized</span> (subscribers) {</div><div class="line">[subscribers addObject:subscriber];</div><div class="line">}</div><div class="line"></div><div class="line">[disposable addDisposable:[RACDisposable disposableWithBlock:^{</div><div class="line"><span class="keyword">@synchronized</span> (subscribers) {</div><div class="line"><span class="built_in">NSUInteger</span> index = [subscribers indexOfObjectWithOptions:<span class="built_in">NSEnumerationReverse</span> passingTest:^ <span class="built_in">BOOL</span> (<span class="keyword">id</span><RACSubscriber> obj, <span class="built_in">NSUInteger</span> index, <span class="built_in">BOOL</span> *stop) {</div><div class="line"><span class="keyword">return</span> obj == subscriber;</div><div class="line">}];</div><div class="line"></div><div class="line"><span class="keyword">if</span> (index != <span class="built_in">NSNotFound</span>) [subscribers removeObjectAtIndex:index];</div><div class="line">}</div><div class="line">}]];</div><div class="line"></div><div class="line"><span class="keyword">return</span> disposable;</div><div class="line">}</div></pre></td></tr></table></figure></li></ol><p><img src="/resources/BC332BF723353C86210F9DA243BB76E3.jpg" alt="IMAGE"><br>发送消息的过程</p><ol><li>遍历当前订阅者列表中有哪些元素</li><li>向订阅者发送订阅的消息<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div></pre></td><td class="code"><pre><div class="line">- (<span class="keyword">void</span>)sendNext:(<span class="keyword">id</span>)value {</div><div class="line">[<span class="keyword">self</span> enumerateSubscribersUsingBlock:^(<span class="keyword">id</span><RACSubscriber> subscriber) {</div><div class="line">[subscriber sendNext:value];</div><div class="line">}];</div><div class="line">}</div><div class="line"></div><div class="line">- (<span class="keyword">void</span>)sendError:(<span class="built_in">NSError</span> *)error {</div><div class="line">[<span class="keyword">self</span>.disposable dispose];</div><div class="line"></div><div class="line">[<span class="keyword">self</span> enumerateSubscribersUsingBlock:^(<span class="keyword">id</span><RACSubscriber> subscriber) {</div><div class="line">[subscriber sendError:error];</div><div class="line">}];</div><div class="line">}</div><div class="line"></div><div class="line">- (<span class="keyword">void</span>)sendCompleted {</div><div class="line">[<span class="keyword">self</span>.disposable dispose];</div><div class="line"></div><div class="line">[<span class="keyword">self</span> enumerateSubscribersUsingBlock:^(<span class="keyword">id</span><RACSubscriber> subscriber) {</div><div class="line">[subscriber sendCompleted];</div><div class="line">}];</div><div class="line">}</div></pre></td></tr></table></figure></li></ol><p>冷信号的使用<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div></pre></td><td class="code"><pre><div class="line">RACSignal *signal = [RACSignal createSignal:^RACDisposable * _Nullable(<span class="keyword">id</span><RACSubscriber> _Nonnull subscriber) {</div><div class="line"> [subscriber sendNext:<span class="string">@"😜"</span>];</div><div class="line"> <span class="keyword">return</span> <span class="literal">nil</span>;</div><div class="line">}];</div><div class="line"></div><div class="line">[signal subscribeNext:^(<span class="keyword">id</span> _Nullable x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"%@"</span>,x); </div><div class="line">}];</div></pre></td></tr></table></figure></p><p>输出<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">HZReactiveCocoaTest_Example[<span class="number">52485</span>:<span class="number">35373322</span>] 😜</div></pre></td></tr></table></figure></p><p>热信号的使用<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div></pre></td><td class="code"><pre><div class="line">RACSubject *subject = [RACSubject subject];</div><div class="line"></div><div class="line"><span class="comment">// Subscriber 1</span></div><div class="line">[subject subscribeNext:^(<span class="keyword">id</span> _Nullable x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"1st Sub: %@"</span>, x);</div><div class="line">}];</div><div class="line">[subject sendNext:@<span class="number">1</span>];</div><div class="line"></div><div class="line"><span class="comment">// Subscriber 2</span></div><div class="line">[subject subscribeNext:^(<span class="keyword">id</span> _Nullable x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"2nd Sub: %@"</span>, x);</div><div class="line">}];</div><div class="line">[subject sendNext:@<span class="number">2</span>];</div><div class="line"></div><div class="line"><span class="comment">// Subscriber 3</span></div><div class="line">[subject subscribeNext:^(<span class="keyword">id</span> _Nullable x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"3rd Sub: %@"</span>, x);</div><div class="line">}];</div><div class="line">[subject sendNext:@<span class="number">3</span>];</div><div class="line">[subject sendCompleted];</div></pre></td></tr></table></figure></p><p>输出<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line">HZReactiveCocoaTest_Example[<span class="number">52559</span>:<span class="number">35393828</span>] <span class="number">1</span>st Sub: <span class="number">1</span></div><div class="line">HZReactiveCocoaTest_Example[<span class="number">52559</span>:<span class="number">35393828</span>] <span class="number">1</span>st Sub: <span class="number">2</span></div><div class="line">HZReactiveCocoaTest_Example[<span class="number">52559</span>:<span class="number">35393828</span>] <span class="number">2</span>nd Sub: <span class="number">2</span></div><div class="line">HZReactiveCocoaTest_Example[<span class="number">52559</span>:<span class="number">35393828</span>] <span class="number">1</span>st Sub: <span class="number">3</span></div><div class="line">HZReactiveCocoaTest_Example[<span class="number">52559</span>:<span class="number">35393828</span>] <span class="number">2</span>nd Sub: <span class="number">3</span></div><div class="line">HZReactiveCocoaTest_Example[<span class="number">52559</span>:<span class="number">35393828</span>] <span class="number">3</span>rd Sub: <span class="number">3</span></div></pre></td></tr></table></figure></p><p>盗一张图来用一下<a href="http://draveness.me/racsubject.html" target="_blank" rel="noopener">出处</a><br><img src="/resources/AD49783AEA246D939670EF5FE1E5B0CA.jpg" alt="IMAGE"><br>热信号不会再订阅的时候向订阅人去发送消息，只会在消息发送出去时候，向订阅者发送消息</p><h3 id="RACGroupedSignal"><a href="#RACGroupedSignal" class="headerlink" title="RACGroupedSignal"></a>RACGroupedSignal</h3><ul><li>解释：分组信号，用来实现 RACSignal 的分组功能；</li><li>作用：信号中包含一个key的属性，用来分组</li><li><p>原理：</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line">+ (<span class="keyword">instancetype</span>)signalWithKey:(<span class="keyword">id</span><<span class="built_in">NSCopying</span>>)key {</div><div class="line">RACGroupedSignal *subject = [<span class="keyword">self</span> subject];</div><div class="line">subject.key = key;</div><div class="line"><span class="keyword">return</span> subject;</div><div class="line">}</div></pre></td></tr></table></figure></li><li><p>案例：</p><ol><li>配合groupBy:transform:进行信号的组合</li><li>所有数字大于3的生成一个good为key的RACGroupedSignal，小于3的会生成一个bad的RACGroupedSignal<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div></pre></td><td class="code"><pre><div class="line">RACSignal *signalA = [RACSignal createSignal:^RACDisposable *(<span class="keyword">id</span><RACSubscriber> subscriber)</div><div class="line"> {</div><div class="line"> [subscriber sendNext:@<span class="number">1</span>];</div><div class="line"> [subscriber sendNext:@<span class="number">2</span>];</div><div class="line"> [subscriber sendNext:@<span class="number">3</span>];</div><div class="line"> [subscriber sendNext:@<span class="number">4</span>];</div><div class="line"> [subscriber sendNext:@<span class="number">5</span>];</div><div class="line"> [subscriber sendCompleted];</div><div class="line"> <span class="keyword">return</span> [RACDisposable disposableWithBlock:^{</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"signal dispose"</span>);</div><div class="line"> }];</div><div class="line"> }];</div><div class="line"> <span class="comment">// 这段代码还无法完全解释，关于filter机制方面还不是很懂，再研究研究</span></div><div class="line"> RACSignal *signalGroup = [signalA groupBy:^<span class="keyword">id</span><<span class="built_in">NSCopying</span>>(<span class="built_in">NSNumber</span> *object) {</div><div class="line"> <span class="keyword">return</span> object.integerValue > <span class="number">3</span> ? <span class="string">@"good"</span> : <span class="string">@"bad"</span>;</div><div class="line"> } transform:^<span class="keyword">id</span>(<span class="built_in">NSNumber</span> * object) {</div><div class="line"> <span class="keyword">return</span> @(object.integerValue * <span class="number">10</span>);</div><div class="line"> }];</div><div class="line"></div><div class="line"> [[[signalGroup filter:^<span class="built_in">BOOL</span>(RACGroupedSignal *value) {</div><div class="line"> <span class="keyword">return</span> [(<span class="built_in">NSString</span> *)value.key isEqualToString:<span class="string">@"good"</span>];</div><div class="line"> }] flatten]subscribeNext:^(<span class="keyword">id</span> x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"subscribeNext: %@"</span>, x);</div><div class="line"> }];</div></pre></td></tr></table></figure></li></ol></li></ul><p>输出<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">HZReactiveCocoaTest_Example[<span class="number">55955</span>:<span class="number">37029147</span>] subscribeNext: <span class="number">40</span></div><div class="line">HZReactiveCocoaTest_Example[<span class="number">55955</span>:<span class="number">37029147</span>] subscribeNext: <span class="number">50</span></div><div class="line">HZReactiveCocoaTest_Example[<span class="number">55955</span>:<span class="number">37029147</span>] signal dispose</div></pre></td></tr></table></figure></p><h3 id="RACBehaviorSubject"><a href="#RACBehaviorSubject" class="headerlink" title="RACBehaviorSubject"></a>RACBehaviorSubject</h3><ul><li>解释：RACBehaviorSubject是对RACSubject的扩充</li><li>作用：在订阅时会向订阅者发送最新的消息，内部会保存一个currentValue即消息的最新值</li><li>原理：内部有一个currentValue属性将数据进行保存。每次sendNext的时候就会将其进行发送</li><li><p>注意点：每次订阅的时候，会默认的去发送一次sendNext:</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">@property</span> (<span class="keyword">nonatomic</span>, <span class="keyword">strong</span>) <span class="keyword">id</span> currentValue;</div><div class="line">- (<span class="keyword">void</span>)sendNext:(<span class="keyword">id</span>)value {</div><div class="line"><span class="keyword">@synchronized</span> (<span class="keyword">self</span>) {</div><div class="line"><span class="keyword">self</span>.currentValue = value;</div><div class="line">[<span class="keyword">super</span> sendNext:value];</div><div class="line">}</div><div class="line">}</div><div class="line">- (RACDisposable *)subscribe:(<span class="keyword">id</span><RACSubscriber>)subscriber {</div><div class="line">RACDisposable *subscriptionDisposable = [<span class="keyword">super</span> subscribe:subscriber];</div><div class="line">RACDisposable *schedulingDisposable = [RACScheduler.subscriptionScheduler schedule:^{</div><div class="line"><span class="keyword">@synchronized</span> (<span class="keyword">self</span>) {</div><div class="line">[subscriber sendNext:<span class="keyword">self</span>.currentValue];</div><div class="line">}</div><div class="line">}];</div><div class="line"></div><div class="line"><span class="keyword">return</span> [RACDisposable disposableWithBlock:^{</div><div class="line">[subscriptionDisposable dispose];</div><div class="line">[schedulingDisposable dispose];</div><div class="line">}];</div><div class="line">}</div></pre></td></tr></table></figure></li><li><p>案例：</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div></pre></td><td class="code"><pre><div class="line">RACBehaviorSubject *subject = [RACBehaviorSubject subject];</div><div class="line"></div><div class="line">[subject subscribeNext:^(<span class="keyword">id</span> _Nullable x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"1st Sub: %@"</span>, x);</div><div class="line">}];</div><div class="line">[subject sendNext:@<span class="number">1</span>];</div><div class="line"></div><div class="line">[subject subscribeNext:^(<span class="keyword">id</span> _Nullable x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"2nd Sub: %@"</span>, x);</div><div class="line">}];</div><div class="line">[subject sendNext:@<span class="number">2</span>];</div><div class="line"></div><div class="line">[subject subscribeNext:^(<span class="keyword">id</span> _Nullable x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"3rd Sub: %@"</span>, x);</div><div class="line">}];</div><div class="line">[subject sendNext:@<span class="number">3</span>];</div><div class="line">[subject sendCompleted];</div></pre></td></tr></table></figure></li></ul><p>嗯，又要盗图了<br><img src="/resources/9A0C0AC5F26D27C5690B6E7496306B79.jpg" alt="IMAGE"><br>因为默认会发送一次，所以创建的时候允许创建默认值<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">RACBehaviorSubject *subject = [RACBehaviorSubject behaviorSubjectWithDefaultValue:@<span class="number">0</span>];</div></pre></td></tr></table></figure></p><h3 id="RACReplaySubject"><a href="#RACReplaySubject" class="headerlink" title="RACReplaySubject"></a>RACReplaySubject</h3><ul><li>解释：RACReplaySubject则是对RACBehaviorSubject的再一次加强，是保存所有值，而不仅仅是保存最新值</li><li>作用：在订阅时会向订阅者发送热信号创建以来发送过的所有数据</li><li>原理：内部包含有消息数组，默认存储量是无符号整型的最大值<br>发送过程<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line">- (<span class="keyword">void</span>)sendNext:(<span class="keyword">id</span>)value {</div><div class="line"><span class="keyword">@synchronized</span> (<span class="keyword">self</span>) {</div><div class="line">[<span class="keyword">self</span>.valuesReceived addObject:value ?: RACTupleNil.tupleNil];</div><div class="line">[<span class="keyword">super</span> sendNext:value];</div><div class="line"></div><div class="line"><span class="keyword">if</span> (<span class="keyword">self</span>.capacity != RACReplaySubjectUnlimitedCapacity && <span class="keyword">self</span>.valuesReceived.count > <span class="keyword">self</span>.capacity) {</div><div class="line">[<span class="keyword">self</span>.valuesReceived removeObjectsInRange:<span class="built_in">NSMakeRange</span>(<span class="number">0</span>, <span class="keyword">self</span>.valuesReceived.count - <span class="keyword">self</span>.capacity)];</div><div class="line">}</div><div class="line">}</div><div class="line">}</div></pre></td></tr></table></figure></li></ul><p>订阅过程<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div></pre></td><td class="code"><pre><div class="line">- (RACDisposable *)subscribe:(<span class="keyword">id</span><RACSubscriber>)subscriber {</div><div class="line">RACCompoundDisposable *compoundDisposable = [RACCompoundDisposable compoundDisposable];</div><div class="line"></div><div class="line">RACDisposable *schedulingDisposable = [RACScheduler.subscriptionScheduler schedule:^{</div><div class="line"><span class="keyword">@synchronized</span> (<span class="keyword">self</span>) {</div><div class="line"><span class="keyword">for</span> (<span class="keyword">id</span> value <span class="keyword">in</span> <span class="keyword">self</span>.valuesReceived) {</div><div class="line"><span class="keyword">if</span> (compoundDisposable.disposed) <span class="keyword">return</span>;</div><div class="line"></div><div class="line">[subscriber sendNext:(value == RACTupleNil.tupleNil ? <span class="literal">nil</span> : value)];</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">if</span> (compoundDisposable.disposed) <span class="keyword">return</span>;</div><div class="line"></div><div class="line"><span class="keyword">if</span> (<span class="keyword">self</span>.hasCompleted) {</div><div class="line">[subscriber sendCompleted];</div><div class="line">} <span class="keyword">else</span> <span class="keyword">if</span> (<span class="keyword">self</span>.hasError) {</div><div class="line">[subscriber sendError:<span class="keyword">self</span>.error];</div><div class="line">} <span class="keyword">else</span> {</div><div class="line">RACDisposable *subscriptionDisposable = [<span class="keyword">super</span> subscribe:subscriber];</div><div class="line">[compoundDisposable addDisposable:subscriptionDisposable];</div><div class="line">}</div><div class="line">}</div><div class="line">}];</div><div class="line"></div><div class="line">[compoundDisposable addDisposable:schedulingDisposable];</div><div class="line"></div><div class="line"><span class="keyword">return</span> compoundDisposable;</div><div class="line">}</div></pre></td></tr></table></figure></p><ul><li><p>注意点：当然你也可以设置存储历史消息的数量,跟behavior一样，已创建就会发送历史消息</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">+ (<span class="keyword">instancetype</span>)replaySubjectWithCapacity:(<span class="built_in">NSUInteger</span>)capacity {</div><div class="line"><span class="keyword">return</span> [(RACReplaySubject *)[<span class="keyword">self</span> alloc] initWithCapacity:capacity];</div><div class="line">}</div></pre></td></tr></table></figure></li><li><p>使用案例</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div></pre></td><td class="code"><pre><div class="line">RACReplaySubject *subject = [RACReplaySubject subject];</div><div class="line"></div><div class="line">[subject subscribeNext:^(<span class="keyword">id</span> _Nullable x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"1st Subscriber: %@"</span>, x);</div><div class="line">}];</div><div class="line">[subject sendNext:@<span class="number">1</span>];</div><div class="line"></div><div class="line">[subject subscribeNext:^(<span class="keyword">id</span> _Nullable x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"2nd Subscriber: %@"</span>, x);</div><div class="line">}];</div><div class="line">[subject sendNext:@<span class="number">2</span>];</div><div class="line"></div><div class="line">[subject subscribeNext:^(<span class="keyword">id</span> _Nullable x) {</div><div class="line"> <span class="built_in">NSLog</span>(<span class="string">@"3rd Subscriber: %@"</span>, x);</div><div class="line">}];</div><div class="line">[subject sendNext:@<span class="number">3</span>];</div><div class="line">[subject sendCompleted];</div></pre></td></tr></table></figure></li></ul><p>0 0请允许我再盗一次图<br><img src="/resources/2246DA721B846E004E6485B304F0E2A5.jpg" alt="IMAGE"></p><h2 id="参考链接"><a href="#参考链接" class="headerlink" title="参考链接"></a>参考链接</h2><p><a href="http://www.jianshu.com/p/912c69dfb55a" target="_blank" rel="noopener">ReactiveCocoa信号发送详解</a><br><a href="http://draveness.me/racchannel" target="_blank" rel="noopener">RAC 中的双向数据绑定</a><br><a href="http://draveness.me/racsubject.html" target="_blank" rel="noopener">RACSubject</a><br><a href="http://www.jianshu.com/p/707ece08257e" target="_blank" rel="noopener">RACGroupedSignal</a></p>]]></content>
<summary type="html">
<h2 id="信号类基础概念及原理"><a href="#信号类基础概念及原理" class="headerlink" title="信号类基础概念及原理"></a>信号类基础概念及原理</h2><h3 id="信号类的集成关系图"><a href="#信号类的集成关系图" class="headerlink" title="信号类的集成关系图"></a>信号类的集成关系图</h3><p><img src="/resources/FA1CDE683EA35A1CCDBAB883F9B0A64D.jpg" alt="IMAGE"></p>
</summary>
<category term="ReactiveCocoa" scheme="http://www.zhz.io/tags/ReactiveCocoa/"/>
</entry>
<entry>
<title>ReactiveCocoa - 双向绑定，不完全解析</title>
<link href="http://www.zhz.io/2017/08/17/ReactiveCocoa-%E5%8F%8C%E5%90%91%E7%BB%91%E5%AE%9A%EF%BC%8C%E4%B8%8D%E5%AE%8C%E5%85%A8%E8%A7%A3%E6%9E%90/"/>
<id>http://www.zhz.io/2017/08/17/ReactiveCocoa-双向绑定，不完全解析/</id>
<published>2017-08-17T03:00:56.000Z</published>
<updated>2018-02-12T03:03:08.615Z</updated>
<content type="html"><![CDATA[<h3 id="RACChannelTerminal"><a href="#RACChannelTerminal" class="headerlink" title="RACChannelTerminal"></a>RACChannelTerminal</h3><p>我们先来看看双向绑定这件事情。<br><img src="/resources/41863AF8A61873D1D38D72BF3C38FC69.jpg" alt="IMAGE"><br>我们如何实现信号从A传到B，又可以从B传到A呢。利用信号的双向传递的话，我们可以用RACSubject，这样A发的信号B就能接到，而且B发的信号A也能够接收到。<br><img src="/resources/3333985DB5A5A590D5966CFDDFDC34A6.jpg" alt="IMAGE"><br><a id="more"></a><br>这样也有个问题，因为A是Subject的订阅者又是接受者，A发送给B的东西，A也同样会被接受到，这是我们不希望看到的。</p><ul><li>解释：为了解决数据双向传递，特别设计的一个类</li><li>作用：上面已经有描述不再说了</li><li>案例：<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 建立双向绑定方式1</span></div><div class="line">RACChannelTo(<span class="keyword">self</span>,string1) = RACChannelTo(<span class="keyword">self</span>,string2);</div><div class="line"><span class="comment">// 建立双向绑定方式2</span></div><div class="line"><span class="keyword">self</span>.channel1 = [[RACKVOChannel alloc] initWithTarget:<span class="keyword">self</span> keyPath:<span class="string">@"string1"</span> nilValue:<span class="literal">nil</span>];</div><div class="line"><span class="keyword">self</span>.channel2 = [[RACKVOChannel alloc] initWithTarget:<span class="keyword">self</span> keyPath:<span class="string">@"string2"</span> nilValue:<span class="literal">nil</span>];</div><div class="line"><span class="keyword">self</span>.channel1[<span class="string">@"followingTerminal"</span>] = <span class="keyword">self</span>.channel2[<span class="string">@"followingTerminal"</span>];</div></pre></td></tr></table></figure></li></ul><blockquote><p>方案2只是方案1的展开，我们平时用的都是RACKVOChannel。所以以此为例</p></blockquote><ul><li>订阅关系<br><img src="/resources/8053428106F17C5443DC8D72D019093C.jpg" alt="IMAGE"><br>特别解释：</li></ul><ol><li>lead中的value等于follow的other<br>3=7 4=6 10=12 11=13</li><li>同一个Terminal中的信号不会进行互相传递，因为使用ignoreValues进行了忽略(只是提及大可忽略这条规则)</li><li>string1和string2并不是真正的订阅者。这边只是为了显示方便给大家演示这么写了。<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div></pre></td><td class="code"><pre><div class="line"><span class="class"><span class="keyword">@implementation</span> <span class="title">RACChannel</span></span></div><div class="line"></div><div class="line">- (<span class="keyword">instancetype</span>)init {</div><div class="line"><span class="keyword">self</span> = [<span class="keyword">super</span> init];</div><div class="line"></div><div class="line">RACReplaySubject *leadingSubject = [[RACReplaySubject replaySubjectWithCapacity:<span class="number">0</span>] setNameWithFormat:<span class="string">@"leadingSubject"</span>];</div><div class="line">RACReplaySubject *followingSubject = [[RACReplaySubject replaySubjectWithCapacity:<span class="number">1</span>] setNameWithFormat:<span class="string">@"followingSubject"</span>];</div><div class="line"></div><div class="line">[[leadingSubject ignoreValues] subscribe:followingSubject];</div><div class="line">[[followingSubject ignoreValues] subscribe:leadingSubject];</div><div class="line"></div><div class="line"> <span class="comment">// 结合下面的Terminal初始化，即可看到leaf的value和follow的other是相等的</span></div><div class="line">_leadingTerminal = [[[RACChannelTerminal alloc] initWithValues:leadingSubject otherTerminal:followingSubject] setNameWithFormat:<span class="string">@"leadingTerminal"</span>];</div><div class="line">_followingTerminal = [[[RACChannelTerminal alloc] initWithValues:followingSubject otherTerminal:leadingSubject] setNameWithFormat:<span class="string">@"followingTerminal"</span>];</div><div class="line"></div><div class="line"><span class="keyword">return</span> <span class="keyword">self</span>;</div><div class="line">}</div><div class="line"><span class="keyword">@end</span></div><div class="line"></div><div class="line"><span class="class"><span class="keyword">@implementation</span> <span class="title">RACChannelTerminal</span></span></div><div class="line">- (<span class="keyword">instancetype</span>)initWithValues:(RACSignal *)values otherTerminal:(<span class="keyword">id</span><RACSubscriber>)otherTerminal {</div><div class="line"><span class="built_in">NSCParameterAssert</span>(values != <span class="literal">nil</span>);</div><div class="line"><span class="built_in">NSCParameterAssert</span>(otherTerminal != <span class="literal">nil</span>);</div><div class="line"> </div><div class="line"><span class="keyword">self</span> = [<span class="keyword">super</span> init];</div><div class="line"></div><div class="line">_values = values;</div><div class="line">_otherTerminal = otherTerminal;</div><div class="line"></div><div class="line"><span class="keyword">return</span> <span class="keyword">self</span>;</div><div class="line">}</div><div class="line"><span class="keyword">@end</span></div></pre></td></tr></table></figure></li></ol><ul><li>发送流程</li></ul><ol><li>String1开始发出了属性改变的信号。</li><li>由1.2.3这个value订阅者进行信号的接收</li><li>由于3=7，3又是热信号，收到信号后进行信号转发发送给13这个订阅者</li><li>由于13=11，11为热信号，收到信号后，发送给订阅者。执行setValue:ForKey:将值进行传递</li></ol><ul><li>看下代码<br>步骤1中的关键代码<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line"><span class="comment">// 这段是KVC注册属性变化之后的信号回调处理</span></div><div class="line">RACDisposable *observationDisposable = [strongTarget rac_observeKeyPath:keyPath options:<span class="built_in">NSKeyValueObservingOptionInitial</span> observer:<span class="literal">nil</span> block:^(<span class="keyword">id</span> value, <span class="built_in">NSDictionary</span> *change, <span class="built_in">BOOL</span> causedByDealloc, <span class="built_in">BOOL</span> affectedOnlyLastComponent) {</div><div class="line"><span class="keyword">if</span> (!causedByDealloc && affectedOnlyLastComponent && <span class="keyword">self</span>.currentThreadData.ignoreNextUpdate) {</div><div class="line">[<span class="keyword">self</span> destroyCurrentThreadData];</div><div class="line"><span class="keyword">return</span>;</div><div class="line">}</div><div class="line"> <span class="comment">// 交给了leadingTerminal进行信号转发</span></div><div class="line">[<span class="keyword">self</span>.leadingTerminal sendNext:value];</div><div class="line">}];</div></pre></td></tr></table></figure></li></ul><p>在Terminal中，我们可以看到其实terminal只是作为包装而已，真正发送和订阅时由value和other来进行订阅和发送的。<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div></pre></td><td class="code"><pre><div class="line">@implementation RACChannelTerminal</div><div class="line"></div><div class="line">#pragma mark Lifecycle</div><div class="line"></div><div class="line">- (instancetype)initWithValues:(RACSignal *)values otherTerminal:(id<RACSubscriber>)otherTerminal {</div><div class="line">NSCParameterAssert(values != nil);</div><div class="line">NSCParameterAssert(otherTerminal != nil);</div><div class="line"> </div><div class="line">self = [super init];</div><div class="line"></div><div class="line">_values = values;</div><div class="line">_otherTerminal = otherTerminal;</div><div class="line"></div><div class="line">return self;</div><div class="line">}</div><div class="line"></div><div class="line">#pragma mark RACSignal</div><div class="line"></div><div class="line">- (RACDisposable *)subscribe:(id<RACSubscriber>)subscriber {</div><div class="line">return [self.values subscribe:subscriber];</div><div class="line">}</div><div class="line"></div><div class="line">#pragma mark <RACSubscriber></div><div class="line"></div><div class="line">- (void)sendNext:(id)value {</div><div class="line">[self.otherTerminal sendNext:value];</div><div class="line">}</div><div class="line"></div><div class="line">- (void)sendError:(NSError *)error {</div><div class="line">[self.otherTerminal sendError:error];</div><div class="line">}</div><div class="line"></div><div class="line">- (void)sendCompleted {</div><div class="line">[self.otherTerminal sendCompleted];</div><div class="line">}</div><div class="line"></div><div class="line">- (void)didSubscribeWithDisposable:(RACCompoundDisposable *)disposable {</div><div class="line">[self.otherTerminal didSubscribeWithDisposable:disposable];</div><div class="line">}</div><div class="line"></div><div class="line">@end</div></pre></td></tr></table></figure></p><p>步骤4中的关键代码：<br><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div></pre></td><td class="code"><pre><div class="line">[[<span class="keyword">self</span>.leadingTerminal</div><div class="line">finally:^{</div><div class="line">[observationDisposable dispose];</div><div class="line">}]</div><div class="line">subscribeNext:^(<span class="keyword">id</span> x) {</div><div class="line"><span class="built_in">NSObject</span> *object = (keyPathComponentsCount > <span class="number">1</span> ? [<span class="keyword">self</span>.target valueForKeyPath:keyPathByDeletingLastKeyPathComponent] : <span class="keyword">self</span>.target);</div><div class="line"><span class="keyword">if</span> (object == <span class="literal">nil</span>) <span class="keyword">return</span>;</div><div class="line"></div><div class="line">[<span class="keyword">self</span> createCurrentThreadData];</div><div class="line"><span class="keyword">self</span>.currentThreadData.ignoreNextUpdate = <span class="literal">YES</span>;</div><div class="line"> <span class="comment">// 可以看到收到信号后，进行setValue:forKey:进行赋值</span></div><div class="line">[object setValue:x ?: nilValue forKey:lastKeyPathComponent];</div><div class="line">} error:^(<span class="built_in">NSError</span> *error) {</div><div class="line"><span class="built_in">NSCAssert</span>(<span class="literal">NO</span>, <span class="string">@"Received error in %@: %@"</span>, <span class="keyword">self</span>, error);</div><div class="line"></div><div class="line"><span class="comment">// Log the error if we're running with assertions disabled.</span></div><div class="line"><span class="built_in">NSLog</span>(<span class="string">@"Received error in %@: %@"</span>, <span class="keyword">self</span>, error);</div><div class="line">}];</div></pre></td></tr></table></figure></p>]]></content>
<summary type="html">
<h3 id="RACChannelTerminal"><a href="#RACChannelTerminal" class="headerlink" title="RACChannelTerminal"></a>RACChannelTerminal</h3><p>我们先来看看双向绑定这件事情。<br><img src="/resources/41863AF8A61873D1D38D72BF3C38FC69.jpg" alt="IMAGE"><br>我们如何实现信号从A传到B，又可以从B传到A呢。利用信号的双向传递的话，我们可以用RACSubject，这样A发的信号B就能接到，而且B发的信号A也能够接收到。<br><img src="/resources/3333985DB5A5A590D5966CFDDFDC34A6.jpg" alt="IMAGE"><br>
</summary>
<category term="ReactiveCocoa" scheme="http://www.zhz.io/tags/ReactiveCocoa/"/>
</entry>
<entry>
<title>Advanced_Apple_Debugging阅读笔记Part1</title>
<link href="http://www.zhz.io/2017/06/05/Advanced-Apple-Debugging%E9%98%85%E8%AF%BB%E7%AC%94%E8%AE%B0Part1/"/>
<id>http://www.zhz.io/2017/06/05/Advanced-Apple-Debugging阅读笔记Part1/</id>
<published>2017-06-05T13:54:27.000Z</published>
<updated>2017-06-05T13:57:22.000Z</updated>
<content type="html"><![CDATA[<h2 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h2><p>本文为<a href="https://store.raywenderlich.com/products/advanced-apple-debugging-and-reverse-engineering" target="_blank" rel="noopener">Advanced Apple Debugging & Reverse Engineering</a>的第一章阅读笔记，<br>有不正之处望指正</p><h2 id="基础"><a href="#基础" class="headerlink" title="基础"></a>基础</h2><p>关闭Rootless模式</p><ul><li>重启电脑，启动后长按Commond+R</li><li>进入控制台</li><li>输入 csrutil disable; reboot</li><li>不久后就会重启电脑</li></ul><h3 id="File"><a href="#File" class="headerlink" title="File"></a>File</h3><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">$ lldb /Projects/Sketch/build/Debug/Sketch.app </div><div class="line">>> Current executable set to '/Projects/Sketch/build/Debug/Sketch.app' (x86_64)</div></pre></td></tr></table></figure><p>等同于<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">$ lldb </div><div class="line">(lldb) file /Projects/Sketch/build/Debug/Sketch.app </div><div class="line">>> Current executable set to '/Projects/Sketch/build/Debug/Sketch.app' (x86_64).</div></pre></td></tr></table></figure></p><a id="more"></a><h3 id="process"><a href="#process" class="headerlink" title="process"></a>process</h3><ul><li>launch 启动执行目录的程序</li></ul><h3 id="image"><a href="#image" class="headerlink" title="image"></a>image</h3><ul><li><p>lookup </p><ul><li><p>-n NAME 查找具体代码</p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">(lldb) image lookup -n "-[UIViewController viewDidLoad]"</div></pre></td></tr></table></figure></li><li><p>-rn NAME 查找所有符合NAME规则的符号。符号可以正则，所以说符合规则</p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line">(lldb) image lookup -rn test</div><div class="line">#Swift</div><div class="line">(lldb) image lookup -rn Signals.SwiftTestClass.name.setter </div><div class="line">2 matches found in /Users/derekselander/Library/Developer/Xcode/DerivedData/Signals-bqrjxlceauwfuihjesxmgfodimef/Build/Products/Debug-iphonesimulator/Signals.app/Signals:</div><div class="line"> Address: Signals[0x000000010000aba0] (Signals.__TEXT.__text +38704)</div><div class="line"> Summary: Signals`@objc Signals.SwiftTestClass.name.setter :raywenderlich.com 47</div><div class="line"> Advanced Apple Debugging Chapter 4: Stopping in Code Swift.ImplicitlyUnwrappedOptional<Swift.String> at SwiftTestClass.swift</div><div class="line"> Address: Signals[0x000000010000ac60] (Signals.__TEXT.__text + 38896)</div><div class="line"> Summary: Signals`Signals.SwiftTestClass.name.setter :Swift.ImplicitlyUnwrappedOptional<Swift.String> at SwiftTestClass.swift</div><div class="line">#Mark 一下这边出现了两个，是因为这个工程既有Swift代码也有OC代码，苹果为了做桥接加了第一个后续可以无视</div></pre></td></tr></table></figure></li></ul></li></ul><h3 id="Breakpoint"><a href="#Breakpoint" class="headerlink" title="Breakpoint"></a>Breakpoint</h3><ul><li><p>设置断点</p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div></pre></td><td class="code"><pre><div class="line">// 简写的形式</div><div class="line">(lldb) b -[UIViewController viewDidLoad]</div><div class="line"> Breakpoint 1: where = UIKit`-[UIViewController viewDidLoad], address = 0x0000000102bbd788</div><div class="line">//如果想在某个文件中的某行设置一个断点，可使用以下命令：</div><div class="line">(lldb) breakpoint set --file foo.c --line 12</div><div class="line">//如果想给某个函数设置断点，可使用以下命令：</div><div class="line">(lldb) breakpoint set --name foo</div><div class="line">//如果想给C++中所有命名为foo的方法设置断点，可以使用以下命令：</div><div class="line">(lldb) breakpoint set --method foo</div><div class="line"></div><div class="line"># 下面两者等价</div><div class="line">(lldb) b Breakpoints.SwiftTestClass.name.setter :Swift.ImplicitlyUnwrappedOptional<Swift.String></div><div class="line">(lldb) rb SwiftTestClass.name.setter</div><div class="line"></div><div class="line"># 部分正则参考</div><div class="line">(lldb) rb name\.setter // image lookup后给所有匹配上name.setter的打上断点</div><div class="line">(lldb) rb '\-\[UIViewController\ ' // 给这个类的所有方法打上断点</div><div class="line">(lldb) rb '\-\[UIViewController(\(\w+\))?\ ' // 给这个类的所有Category打上断点(没有验证)</div><div class="line">(lldb) rb . -f DetailViewController.swift // 给这个文件内的所有方法打上断点</div><div class="line">(lldb) rb . //给所有的方法打上断点 很危险</div><div class="line">(lldb) rb . -s UIKit // 只断点UIKit库里面的所有方法</div><div class="line"></div><div class="line"># 特殊用法</div><div class="line">^(@).* 这个需要考证是用来屏蔽上面说的桥接问题</div></pre></td></tr></table></figure></li><li><p>其他操作</p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div></pre></td><td class="code"><pre><div class="line"> # 断点列表</div><div class="line"> (lldb) breakpoint list 1</div><div class="line"> 1: name = 'main', locations = 20, resolved = 20, hit count = 0</div><div class="line">1.1: where = Breakpoints`main + 22 at AppDelegate.swift:12, address =0x00000001057676e6, resolved, hit count = 0</div><div class="line">1.2: where = Foundation`-[NSThread main], address = 0x000000010584d182,resolved, hit count = 0</div><div class="line">1.3: where = Foundation`-[NSBlockOperation main], address =0x000000010585df4a, resolved, hit count = 0</div><div class="line">...</div><div class="line"></div><div class="line"> # 断点删除</div><div class="line"> (lldb) breakpoint delete 1</div><div class="line"> (lldb) breakpoint delete 1.1 这个准确的说是disable并不是真正意义上的删除</div></pre></td></tr></table></figure></li></ul><h3 id="Expression-amp-po-amp-p"><a href="#Expression-amp-po-amp-p" class="headerlink" title="Expression & po & p"></a>Expression & po & p</h3><p>po = expression -O –</p><p>Note: lldb的Context的问题，如果当前代码是在OC下的话要用OC语法，如果是在Swift的环境下要用Swift代码<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div></pre></td><td class="code"><pre><div class="line"># Swift环境下</div><div class="line">(lldb) po [UIApplication sharedApplication] # 不能这么使用</div><div class="line">(lldb) expression -l objc -O -- [UIApplication sharedApplication]</div><div class="line">(lldb) po UIApplication.shared </div><div class="line"></div><div class="line"># OC环境下</div><div class="line">(lldb) po $R0.title</div><div class="line">(lldb) expression -l swift -- $R0.title</div></pre></td></tr></table></figure></p><p>创建实例的时候要在实例名字前面加$符号，不然不能够正常使用<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line"># 反例</div><div class="line">(lldb) po id test = [NSObject new]</div><div class="line">(lldb) po test</div><div class="line">error: use of undeclared identifier 'test'</div><div class="line"></div><div class="line"># 正确用法</div><div class="line">(lldb) po id $test = [NSObject new]</div><div class="line">(lldb) po $test</div><div class="line"><NSObject: 0x60000001d190></div><div class="line">(lldb) expression -l swift -O -- $test</div></pre></td></tr></table></figure></p><p>细节：在用Expression调用方法的时候，设置的Breakpoint是不会被主动触发的。<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div></pre></td><td class="code"><pre><div class="line"># 不会被触发</div><div class="line">(lldb) expression -l swift -O -- $R0.viewDidLoad()</div><div class="line"># 会被触发</div><div class="line">(lldb) expression -l swift -O -i 0 -- $R0.viewDidLoad()</div></pre></td></tr></table></figure></p><h3 id="Thread-Frame-amp-Step"><a href="#Thread-Frame-amp-Step" class="headerlink" title="Thread, Frame & Step"></a>Thread, Frame & Step</h3><ul><li><p>Thread & Frame</p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div></pre></td><td class="code"><pre><div class="line"> # 打印当前栈内情况</div><div class="line">(lldb) thread backtrace</div><div class="line"> # 打印栈顶信息</div><div class="line">(lldb) frame info</div><div class="line">frame #0: 0x00000001075d0ae0 Signals`MasterViewController.viewWillAppear(animated=<invalid> (0xd1),self=0x00007fff5862dac0) -> () at MasterViewController.swift:47</div><div class="line"> # 根据数据选择栈</div><div class="line"> (lldb) frame select 1</div><div class="line"> # 打印当前所在栈块内的实例</div><div class="line"> (lldb) frame variable</div><div class="line"> # 打印self 符号的所有实例</div><div class="line"> (lldb) frame variable -F self</div></pre></td></tr></table></figure></li><li><p>Step</p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line"># 重新启动程序</div><div class="line">(lldb) run</div><div class="line"># 继续</div><div class="line">(lldb) continue</div><div class="line"># 断点下一步 step over</div><div class="line">(lldb) next</div><div class="line"># 进入函数下一步 step into</div><div class="line">(lldb) step</div><div class="line"># 跳出当前函数 step out</div><div class="line">(lldb) finish</div></pre></td></tr></table></figure></li></ul><h3 id="TypeFormat"><a href="#TypeFormat" class="headerlink" title="TypeFormat"></a>TypeFormat</h3><p><a href="https://sourceware.org/gdb/ onlinedocs/gdb/Output-Formats.html" target="_blank" rel="noopener">参考链接</a></p><h3 id="Customizing-Commands"><a href="#Customizing-Commands" class="headerlink" title="Customizing Commands"></a>Customizing Commands</h3><ol><li>LLDB支持自定义命令行操作 (著名的chisel就是使用这种方法进行编写的)。<figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line"># 这个命令相比大家都不陌生，是用来打印当前的视图结构的</div><div class="line">(lldb) po [[[[[UIApplication sharedApplication] keyWindow] rootViewController] view] recursiveDescription]</div><div class="line"></div><div class="line"># 自定义命令(运行时替换)</div><div class="line"># Note：如果想全局替换可以把这个写入~/.lldbinit里面即可</div><div class="line">(lldb) command alias -- Yay_Autolayout expression -l objc -O -- [[[[[UIApplication sharedApplication] keyWindow] rootViewController] view] recursiveDescription]</div><div class="line"></div><div class="line"># 下面的调用等价于第一个</div><div class="line">(lldb) Yay_Autolayout</div></pre></td></tr></table></figure></li></ol><h3 id="正则表达"><a href="#正则表达" class="headerlink" title="正则表达"></a>正则表达</h3><ul><li>LLDB的正则实现原理是基于Shell的SED命令，详细可以参考sed命令<figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">(lldb) command regex rlook 's/(.+)/image lookup -rn %1/'</div><div class="line">(lldb) rlook viewDidLoad</div></pre></td></tr></table></figure></li></ul><h3 id="简写"><a href="#简写" class="headerlink" title="简写"></a>简写</h3><p>c = continue<br>ex = expression<br>b = breakpoint<br>n = next</p><h3 id="杂项"><a href="#杂项" class="headerlink" title="杂项"></a>杂项</h3><ul><li>$ ttys //查找当前终端的名称<figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">~ $ tty</div><div class="line">>> /dev/ttys027</div></pre></td></tr></table></figure></li></ul>]]></content>
<summary type="html">
<h2 id="前言"><a href="#前言" class="headerlink" title="前言"></a>前言</h2><p>本文为<a href="https://store.raywenderlich.com/products/advanced-apple-debugging-and-reverse-engineering" target="_blank" rel="noopener">Advanced Apple Debugging &amp; Reverse Engineering</a>的第一章阅读笔记，<br>有不正之处望指正</p>
<h2 id="基础"><a href="#基础" class="headerlink" title="基础"></a>基础</h2><p>关闭Rootless模式</p>
<ul>
<li>重启电脑，启动后长按Commond+R</li>
<li>进入控制台</li>
<li>输入 csrutil disable; reboot</li>
<li>不久后就会重启电脑</li>
</ul>
<h3 id="File"><a href="#File" class="headerlink" title="File"></a>File</h3><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">$ lldb /Projects/Sketch/build/Debug/Sketch.app </div><div class="line">&gt;&gt; Current executable set to &apos;/Projects/Sketch/build/Debug/Sketch.app&apos; (x86_64)</div></pre></td></tr></table></figure>
<p>等同于<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">$ lldb </div><div class="line">(lldb) file /Projects/Sketch/build/Debug/Sketch.app </div><div class="line">&gt;&gt; Current executable set to &apos;/Projects/Sketch/build/Debug/Sketch.app&apos; (x86_64).</div></pre></td></tr></table></figure></p>
</summary>
<category term="LLDB" scheme="http://www.zhz.io/tags/LLDB/"/>
</entry>
<entry>
<title>Block 的为什么会有循环引用</title>
<link href="http://www.zhz.io/2017/03/15/Block-%E7%9A%84%E4%B8%BA%E4%BB%80%E4%B9%88%E4%BC%9A%E6%9C%89%E5%BE%AA%E7%8E%AF%E5%BC%95%E7%94%A8/"/>
<id>http://www.zhz.io/2017/03/15/Block-的为什么会有循环引用/</id>
<published>2017-03-15T02:52:13.000Z</published>
<updated>2018-02-12T02:53:13.793Z</updated>
<content type="html"><![CDATA[<h2 id="这次分享要解决的问题"><a href="#这次分享要解决的问题" class="headerlink" title="这次分享要解决的问题"></a>这次分享要解决的问题</h2><p>Block 为什么会引起循环引用</p><h2 id="本次实验"><a href="#本次实验" class="headerlink" title="本次实验"></a>本次实验</h2><ul><li>平台信息</li><li>Apple LLVM version 8.0.0 (clang-800.0.42.1)</li><li>Target: x86_64-apple-darwin16.4.0</li><li>Thread model: posix</li><li>InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin</li><li>MRC</li></ul><a id="more"></a><h2 id="为什么会出现循环引用"><a href="#为什么会出现循环引用" class="headerlink" title="为什么会出现循环引用"></a>为什么会出现循环引用</h2><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line"> +-----------+ +-----------+</div><div class="line"> | instance | | Block |</div><div class="line">---> | | --------> | |</div><div class="line"> | retain 2 | <-------- | retain 1 |</div><div class="line"> | | | |</div><div class="line"> +-----------+ +-----------+</div></pre></td></tr></table></figure><p>如上图所示。两个实例相互持有。<br>1.如果要释放instance，那么要先释放Block。<br>2.如果要释放block，那么要先释放instance。<br>条件1和2不能够同时满足，那么两个都不会被进行释放，这就是所谓的循环引用。</p><h2 id="Block的实现"><a href="#Block的实现" class="headerlink" title="Block的实现"></a>Block的实现</h2><p>工具Clang（GCC的替代品）,编译源码生成可执行文件。<br><em>–rewrite-objc</em>将OC的.m文件转换为cpp文件。<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">clang -rewrite-objc Test.m</div></pre></td></tr></table></figure></p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div></pre></td><td class="code"><pre><div class="line">#import <Foundation/Foundation.h></div><div class="line"></div><div class="line">int main(int argc, const char * argv[]) {</div><div class="line"> @autoreleasepool {</div><div class="line"> // insert code here...</div><div class="line"> NSLog(@"Hello, World!");</div><div class="line"> ^{</div><div class="line"> NSLog(@"Hello Block");</div><div class="line"> }();</div><div class="line"> }</div><div class="line"> return 0;</div><div class="line">}</div></pre></td></tr></table></figure><p>利用Clang命令对源码进行重写。提取关键代码。<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div></pre></td><td class="code"><pre><div class="line">struct __block_impl {</div><div class="line"> void *isa;</div><div class="line"> int Flags;</div><div class="line"> int Reserved;</div><div class="line"> void *FuncPtr;</div><div class="line">};</div><div class="line"></div><div class="line">struct __main_block_impl_0 {</div><div class="line"> struct __block_impl impl;</div><div class="line"> struct __main_block_desc_0* Desc;</div><div class="line"> __main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, int flags=0) {</div><div class="line"> impl.isa = &_NSConcreteStackBlock;</div><div class="line"> impl.Flags = flags;</div><div class="line"> impl.FuncPtr = fp;</div><div class="line"> Desc = desc;</div><div class="line"> }</div><div class="line">};</div><div class="line"></div><div class="line">static void __main_block_func_0(struct __main_block_impl_0 *__cself) {</div><div class="line"> NSLog((NSString *)&__NSConstantStringImpl__var_folders_dz_d6n3371d4951v8wz6yx9tbwc0000gn_T_main_cd25fe_mi_1);</div><div class="line">}</div><div class="line"></div><div class="line">static struct __main_block_desc_0 {</div><div class="line"> size_t reserved;</div><div class="line"> size_t Block_size;</div><div class="line">} __main_block_desc_0_DATA = { 0, sizeof(struct __main_block_impl_0)};</div><div class="line"></div><div class="line"></div><div class="line">((void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA))();</div></pre></td></tr></table></figure></p><p>从中我们可以得到些什么关键的数据<br>一个基础block结构体<strong>_block_imp</strong><br>一个静态C函数<strong>_main_block_func_0</strong>（命名方式：当前类的函数名+block+func+当前Block在文件中Block的序列号。）<br>一个block的结构体<strong>_main_block_impl_0</strong>(命名方式：当前类的函数名+block+impl+当前Block在文件中Block的序列号。)<br>一个block的解释体<strong>main_block_desc_0</strong>(命名方式：当前类的函数名+desc+impl+当前Block在文件中Block的序列号。)</p><p>简化得到基础的Block结构体模型<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div></pre></td><td class="code"><pre><div class="line">struct Block_literal_1 {</div><div class="line"> void *isa;//ARC:__NSMallocBlock__/__NSGlobalBlock__ MRC:__NSMallocBlock__/__NSStackBlock__/__NSGlobalBlock__</div><div class="line"> int flags;//copy到堆时候用的标识</div><div class="line"> int reserved;//保留变量</div><div class="line"> void (*invoke)(void *, ...);//函数指针，实际Block的函数调用地址，类似于实例方法的IMP</div><div class="line"> struct Block_descriptor_1 *descriptor;//Block描述信息</div><div class="line">};</div><div class="line">//非本节关注点。有兴趣自由研究。</div><div class="line">struct Block_descriptor_1 {</div><div class="line"> unsigned long int reserved;//保留变量</div><div class="line"> unsigned long int size;//Block在内存中的大小</div><div class="line"> void (*copy)(void *dst, void *src);//copy到堆上使用的方法</div><div class="line"> void (*dispose)(void *);//执行Release操作</div><div class="line"> const char *signature;//函数签名</div><div class="line">};</div></pre></td></tr></table></figure></p><ul><li><strong>NSMallocBlock</strong>:堆区</li><li><strong>NSStackBlock</strong> :栈区</li><li><strong>NSGlobalBlock</strong>:Data/Text区</li></ul><h2 id="Block参数自动捕获机制"><a href="#Block参数自动捕获机制" class="headerlink" title="Block参数自动捕获机制"></a>Block参数自动捕获机制</h2><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div></pre></td><td class="code"><pre><div class="line">#import <Foundation/Foundation.h></div><div class="line"></div><div class="line">int main(int argc, const char * argv[]) {</div><div class="line"> @autoreleasepool {</div><div class="line"> // insert code here...</div><div class="line"> NSLog(@"Hello, World!");</div><div class="line"> NSString *a = nil;</div><div class="line"> ^{</div><div class="line"> NSLog(@"%@",a);</div><div class="line"> NSLog(@"Hello Block");</div><div class="line"> }();</div><div class="line"> }</div><div class="line"> return 0;</div><div class="line">}</div></pre></td></tr></table></figure><p>简化上述描述，最后得到结果Block为如下值，从中我们可以看到Block的结构体实例会持有a。<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line">struct Block_literal_1 {</div><div class="line"> void *isa;</div><div class="line"> int flags;</div><div class="line"> int reserved;</div><div class="line"> void (*invoke)(void *, ...);</div><div class="line"> struct Block_descriptor_1 *descriptor;</div><div class="line"> </div><div class="line"> NSString *a;</div><div class="line">};</div></pre></td></tr></table></figure></p><p>看完了C的这些实现我们来看OC的代码,测试代码如下<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div></pre></td><td class="code"><pre><div class="line">@interface Test ()</div><div class="line">@property (nonatomic, strong) NSString *a;</div><div class="line">@end</div><div class="line"></div><div class="line">@implementation Test</div><div class="line">- (void)test{</div><div class="line"> ^{</div><div class="line"> NSLog(@"%@",self.a);</div><div class="line"> NSLog(@"Hello Block");</div><div class="line"> }();</div><div class="line">}</div><div class="line">@end</div></pre></td></tr></table></figure></p><p>简化得到Block如下,从中我们看到其实Block是持有self的。<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line">struct Block_literal_1 {</div><div class="line"> void *isa;</div><div class="line"> int flags;</div><div class="line"> int reserved;</div><div class="line"> void (*invoke)(void *, ...);</div><div class="line"> struct Block_descriptor_1 *descriptor;</div><div class="line"> </div><div class="line"> Test *self;</div><div class="line">};</div></pre></td></tr></table></figure></p><p>所以Block是通过持有self实例来调用a的成员变量<br>简化版调用a成员变量的实现<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line">static void __Test__test_block_func_0(struct __Test__test_block_impl_0 *__cself) {</div><div class="line"> Test *self = __cself->self; // bound by copy</div><div class="line"> NSLog((NSString *)objc_msgSend)((id)self, sel_registerName("a"));</div><div class="line"> NSLog((NSString *)&__NSConstantStringImpl__var_folders_dz_d6n3371d4951v8wz6yx9tbwc0000gn_T_Test_92b943_mi_1);</div><div class="line"> }</div></pre></td></tr></table></figure></p><h2 id="实际使用"><a href="#实际使用" class="headerlink" title="实际使用"></a>实际使用</h2><p>retain cycle问题的根源在于Block和obj可能会互相强引用，互相retain对方，这样就导致了retain cycle，最后这个Block和obj就变成了孤岛，谁也释放不了谁。比如：</p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div></pre></td><td class="code"><pre><div class="line">ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];</div><div class="line">[request setCompletionBlock:^{</div><div class="line"> NSString* string = [request responseString];</div><div class="line">}];</div><div class="line"></div><div class="line"> +-----------+ +-----------+</div><div class="line"> | request | | Block |</div><div class="line">---> | | --------> | |</div><div class="line"> | retain 2 | <-------- | retain 1 |</div><div class="line"> | | | |</div><div class="line"> +-----------+ +-----------+</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div></pre></td><td class="code"><pre><div class="line"> __block ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];</div><div class="line"> [request setCompletionBlock:^{</div><div class="line"> NSString* string = [request responseString];</div><div class="line"> }];</div><div class="line"> +-----------+ +-----------+</div><div class="line"> | request | | Block |</div><div class="line">---->| | --------> | |</div><div class="line"> | retain 1 | < - - - - | retain 1 |</div><div class="line"> | | weak | |</div><div class="line"> +-----------+ +-----------+</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div></pre></td><td class="code"><pre><div class="line">ClassA* objA = [[[ClassA alloc] init] autorelease];</div><div class="line">objA.myBlock = ^{</div><div class="line"> [self doSomething];</div><div class="line">};</div><div class="line">self.objA = objA;</div><div class="line"></div><div class="line">+-----------+ +-----------+ +-----------+</div><div class="line">| self | | objA | | Block |</div><div class="line">| | --------> | | --------> | |</div><div class="line">| retain 2 | | retain 1 | | retain 1 |</div><div class="line">| | | | | |</div><div class="line">+-----------+ +-----------+ +-----------+</div><div class="line"> ^ |</div><div class="line"> | |</div><div class="line"> +------------------------------------------------+</div></pre></td></tr></table></figure><h2 id="扩展知识"><a href="#扩展知识" class="headerlink" title="扩展知识"></a>扩展知识</h2><p>__block和__weak实现原理（有兴趣的自行了解）<br>关键代码<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div></pre></td><td class="code"><pre><div class="line">struct __Block_byref_weakSelf_0 {</div><div class="line"> void *__isa;</div><div class="line">__Block_byref_weakSelf_0 *__forwarding;</div><div class="line"> int __flags;</div><div class="line"> int __size;</div><div class="line"> void (*__Block_byref_id_object_copy)(void*, void*);</div><div class="line"> void (*__Block_byref_id_object_dispose)(void*);</div><div class="line"> typeof (self) weakSelf;</div><div class="line">};</div><div class="line">struct __Test__test_block_impl_0 {</div><div class="line"> struct __block_impl impl;</div><div class="line"> struct __Test__test_block_desc_0* Desc;</div><div class="line"> __Block_byref_weakSelf_0 *weakSelf; // by ref</div><div class="line"> __Block_byref_string_1 *string; // by ref</div><div class="line"> __Test__test_block_impl_0(void *fp, struct __Test__test_block_desc_0 *desc, __Block_byref_weakSelf_0 *_weakSelf, __Block_byref_string_1 *_string, int flags=0) : weakSelf(_weakSelf->__forwarding), string(_string->__forwarding) {</div><div class="line"> impl.isa = &_NSConcreteStackBlock;</div><div class="line"> impl.Flags = flags;</div><div class="line"> impl.FuncPtr = fp;</div><div class="line"> Desc = desc;</div><div class="line"> }</div><div class="line">};</div><div class="line">static void __Test__test_block_dispose_0(struct __Test__test_block_impl_0*src) {_Block_object_dispose((void*)src->self, 3/*BLOCK_FIELD_IS_OBJECT*/);}</div><div class="line">static void __Test__test_block_dispose_0(struct __Test__test_block_impl_0*src) {_Block_object_dispose((void*)src->weakSelf, 8/*BLOCK_FIELD_IS_BYREF*/);}</div></pre></td></tr></table></figure></p><h2 id="参考文档"><a href="#参考文档" class="headerlink" title="参考文档"></a>参考文档</h2><p><a href="http://clang.llvm.org/docs/Block-ABI-Apple.html" target="_blank" rel="noopener">LLVM 中 block 实现源码</a><br><a href="http://blog.devtang.com/2013/07/28/a-look-inside-blocks/" target="_blank" rel="noopener">谈Objective-C block的实现</a><br><a href="http://tanqisen.github.io/blog/2013/04/19/gcd-block-cycle-retain/" target="_blank" rel="noopener">文中实际使用举例</a><br><a href="https://github.com/deput/NSInvocation-Block/blob/master/NSInvocation%2BBlock.m" target="_blank" rel="noopener">NSInvocation<->block</a></p>]]></content>
<summary type="html">
<h2 id="这次分享要解决的问题"><a href="#这次分享要解决的问题" class="headerlink" title="这次分享要解决的问题"></a>这次分享要解决的问题</h2><p>Block 为什么会引起循环引用</p>
<h2 id="本次实验"><a href="#本次实验" class="headerlink" title="本次实验"></a>本次实验</h2><ul>
<li>平台信息</li>
<li>Apple LLVM version 8.0.0 (clang-800.0.42.1)</li>
<li>Target: x86_64-apple-darwin16.4.0</li>
<li>Thread model: posix</li>
<li>InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin</li>
<li>MRC</li>
</ul>
</summary>
</entry>
<entry>
<title>我的2016年总结</title>
<link href="http://www.zhz.io/2016/12/31/%E6%88%91%E7%9A%842016%E5%B9%B4%E6%80%BB%E7%BB%93/"/>
<id>http://www.zhz.io/2016/12/31/我的2016年总结/</id>
<published>2016-12-31T04:44:36.000Z</published>
<updated>2018-02-12T02:54:15.000Z</updated>
<content type="html"><![CDATA[<h2 id="0x00-前言"><a href="#0x00-前言" class="headerlink" title="0x00 前言"></a>0x00 前言</h2><p>呵呵哒，这好像是我第一次写这种总结（非逼迫性），来记录一下今年我都干了写啥蠢事。<br>OK~2016年，就这样过去了，这几天看了几个小伙伴和一些人的博客，套用下模板吧。The Good The Bad</p><h2 id="0x01-The-Good"><a href="#0x01-The-Good" class="headerlink" title="0x01 The Good"></a>0x01 The Good</h2><p>今年顺利毕业了，算是度过了人生中最后一段学校的时光。<br>今年的变化还是挺多的吧，单从职业上来说，从学生变成了从业者。从生活上来说，从一个满受父母关怀的孩子变成了一个独立者。</p><h2 id="看了挺多的书"><a href="#看了挺多的书" class="headerlink" title="看了挺多的书"></a>看了挺多的书</h2><p>今年看了挺多的书吧，比如说CA、OC编程之道、Effective Objective-C、代码之外的生存指南等等。收益良多，了解了更多iOS底层的东西，对于后续帮助的确挺大的。<br><a id="more"></a></p><h2 id="从业务转向组件"><a href="#从业务转向组件" class="headerlink" title="从业务转向组件"></a>从业务转向组件</h2><p>来到了一家1K以上规模的公司，终于可以开始不用写一些业务上面的代码了，对于我来说，感觉业务的代码比较繁琐，因为平时的工作量比较多，所以想研究一些东西变成了不可能。<br>现在有所好转，可以开始重构一些模块，开始做一些模块化的东西，接触一些之前会接触不到的东西。慢慢的开始优化自己的代码，因为我写的并不是只有我一个人用，而是面向整个团队。</p><h2 id="提升工作效率的方法并不是加班"><a href="#提升工作效率的方法并不是加班" class="headerlink" title="提升工作效率的方法并不是加班"></a>提升工作效率的方法并不是加班</h2><p>有段时间，曾经强迫自己每天晚上一定要加班，把自己搞的累死累活的，重复着一样的工作。然而并没有什么很好的进展，工作完成量和时间成了一次性方程直线。<br>在做自动化静态库构建的时候，刚开始并没有完整的理解Ruby语言的魅力，导致自己走了很多的弯路，而且少了错过了很多更加有效的方案方法。</p><h2 id="当下能做的为什么要拖到明天"><a href="#当下能做的为什么要拖到明天" class="headerlink" title="当下能做的为什么要拖到明天"></a>当下能做的为什么要拖到明天</h2><p>这应该算一个方法的转变吧，我觉得我是一个很懒的人，所以一直都是这件事情明天做吧，那就放到明天好了。当时这个明天就永远变成了明天。这是我不愿意看到的，所以开始慢慢的调整自己的习惯。从小事做起吧，比如说，洗衣机的衣服洗好了，那就马上去晒掉，不丢到明天。</p><h2 id="1年-1年？"><a href="#1年-1年？" class="headerlink" title="1年=1年？"></a>1年=1年？</h2><p>在技术圈子里时不时就会听到这句话，“技术无时无刻都在变化，你永远都不知道下一秒变成了什么”。我听到了另外一句话，“你的一年是几年”，你是每天重复着一样的工作，还是说你无时无刻都在学习。</p><h2 id="0x02-The-Bad"><a href="#0x02-The-Bad" class="headerlink" title="0x02 The Bad"></a>0x02 The Bad</h2><h2 id="年初定下的一些目标并没有实现"><a href="#年初定下的一些目标并没有实现" class="headerlink" title="年初定下的一些目标并没有实现"></a>年初定下的一些目标并没有实现</h2><p>关于年初定了一堆的目标，被遗忘了好多了。呵呵哒。其中有个减肥的好像被遗忘的特别严重吧。去年狠下心减了那么多，今年弹了一部分。<br>改进：可能要实行一些GTD的方案，来规划一下后面走的路。</p><h2 id="认识的人太少了"><a href="#认识的人太少了" class="headerlink" title="认识的人太少了"></a>认识的人太少了</h2><p>不知道是不是因为工作了的关系，开始认识的人越来越少，自己的圈子被局限了起来。一些交流会感觉无意义就被略过了，或者已没时间为借口匆匆的避开了一系列聚会。和朋友之间呆的时间也开始变少了。或者说知心朋友应该是越来越少了吧。<br>改进：多参加一些技术交流会吧，即使不是技术的。</p><h2 id="其他领域的知识狩猎太少了"><a href="#其他领域的知识狩猎太少了" class="headerlink" title="其他领域的知识狩猎太少了"></a>其他领域的知识狩猎太少了</h2><p>今年一股脑门的投入在iOS圈子里面，对于其他的技术了解的太少了，还好最后一个月，在写一些脚本构建方面的东西，从而能够学习到一些Shell和Ruby。不然真的要被OC给玩死了，到头来一点意思都没有。几年都不加语言特性（呵呵哒）。<br>改进：应该会对一些其他领域进行研究，特别是安全方面的。</p><h2 id="重构上测试写太少了"><a href="#重构上测试写太少了" class="headerlink" title="重构上测试写太少了"></a>重构上测试写太少了</h2><p>最后几个月重构了一些东西，但是呢出了线上Bug，原因都很简单，都是几分钟内解决的小Bug，而且一些测试明显就能够测试出来。哎~只能说自己重构前没有写测试吧。导致自己犯了一些很低级的错误。<br>改进：以后重构的时候前写好单元测试和功能测试吧。</p><h2 id="0x03-2017-一些计划"><a href="#0x03-2017-一些计划" class="headerlink" title="0x03 2017 一些计划"></a>0x03 2017 一些计划</h2><ol><li>明确自己的人生目标（应该是阶段性的目标）</li><li>去一次日本</li><li>改变自己</li><li>能够从容的应对各种事情</li></ol>]]></content>
<summary type="html">
<h2 id="0x00-前言"><a href="#0x00-前言" class="headerlink" title="0x00 前言"></a>0x00 前言</h2><p>呵呵哒，这好像是我第一次写这种总结（非逼迫性），来记录一下今年我都干了写啥蠢事。<br>OK~2016年，就这样过去了，这几天看了几个小伙伴和一些人的博客，套用下模板吧。The Good The Bad</p>
<h2 id="0x01-The-Good"><a href="#0x01-The-Good" class="headerlink" title="0x01 The Good"></a>0x01 The Good</h2><p>今年顺利毕业了，算是度过了人生中最后一段学校的时光。<br>今年的变化还是挺多的吧，单从职业上来说，从学生变成了从业者。从生活上来说，从一个满受父母关怀的孩子变成了一个独立者。</p>
<h2 id="看了挺多的书"><a href="#看了挺多的书" class="headerlink" title="看了挺多的书"></a>看了挺多的书</h2><p>今年看了挺多的书吧，比如说CA、OC编程之道、Effective Objective-C、代码之外的生存指南等等。收益良多，了解了更多iOS底层的东西，对于后续帮助的确挺大的。<br>
</summary>
<category term="总结" scheme="http://www.zhz.io/tags/%E6%80%BB%E7%BB%93/"/>
</entry>
<entry>
<title>Cocoapods常用命令</title>
<link href="http://www.zhz.io/2016/12/15/Cocoapods%E5%B8%B8%E7%94%A8%E5%91%BD%E4%BB%A4/"/>
<id>http://www.zhz.io/2016/12/15/Cocoapods常用命令/</id>
<published>2016-12-15T08:57:23.000Z</published>
<updated>2016-12-15T09:01:08.000Z</updated>
<content type="html"><![CDATA[<h1 id="0x00-Pod基础"><a href="#0x00-Pod基础" class="headerlink" title="0x00 Pod基础"></a>0x00 Pod基础</h1><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">pod --help 这个可以用来所有的命令</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">$ pod [Commond] [Options]</div><div class="line">$ pod install --verbose --no-repo-update</div></pre></td></tr></table></figure><a id="more"></a><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div></pre></td><td class="code"><pre><div class="line">文件目录</div><div class="line">which pod Pod组件安装的目录</div><div class="line"></div><div class="line">Find里面进入./cocoapods可以看到你本地所有的仓库</div></pre></td></tr></table></figure><p>Commonds<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">pod setup 重新安装master仓库，最好别用。因为会把master库删掉，然后下载又很慢，可以用Airdrop让别人给你传一份。</div></pre></td></tr></table></figure></p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">pod install </div><div class="line">官方说法:Install project dependencies according to versions from a Podfile.lock</div><div class="line">解释:解析.podfile文件，跟本地的podfile进行比对，并按不同之处重新进行依赖关系修复。</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line">pod update </div><div class="line">官方说法:Update outdated project dependencies and create new Podfile.lock</div><div class="line">解释:解析.podfile文件，忽略本地的Podfile.lock文件，重新生成Podfile</div><div class="line"></div><div class="line">pod update Your_Project_Name</div><div class="line">解释:仅仅更新Name仓库</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">pod search [name]</div><div class="line">官方说法:Search for pods</div><div class="line">解释:扫描本地的./cocoapods目录下所有的podspec。匹配含有name的项目</div></pre></td></tr></table></figure><p>Options </p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">--verbose </div><div class="line">官方说法:Show more debugging information</div><div class="line">解释:显示出所有Debug信息</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">--no-repo-update</div><div class="line">解释:不去更新现有的本地仓库（包括master，和私有的）</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">--version 当前使用Cocoapods的版本</div></pre></td></tr></table></figure><p>###本地gems的程序安装包，可以看到Cocoapods一共安装了那些组件<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">$ gem list</div></pre></td></tr></table></figure></p><p>###找到对应的组件，可以移除安装包<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">$ sudo gem uninstall cocoapods -v 0.35.0</div></pre></td></tr></table></figure></p><p>###安装制定版本的安装包<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">$ sudo gem install cocoapods -v 0.34.4</div></pre></td></tr></table></figure></p><p>###查看本地的源路径<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">$ gem sources -l</div></pre></td></tr></table></figure></p><p>###切换Gem Source<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">#淘宝的据说已经不维护了</div><div class="line">$ gem sources --add https://gems.ruby-china.org/ #添加源</div><div class="line">$ gem sources --remove https://rubygems.org/ #移除源</div></pre></td></tr></table></figure></p><h1 id="0x00-Pod进阶"><a href="#0x00-Pod进阶" class="headerlink" title="0x00 Pod进阶"></a>0x00 Pod进阶</h1><p>Commonds<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div></pre></td><td class="code"><pre><div class="line">pod cache </div><div class="line">官方解释:Manipulate the CocoaPods cache</div><div class="line">解释:本地的依赖库缓存，不是项目工程Pods下的缓存。</div><div class="line"></div><div class="line">pod cache list 显示所有的本地缓存</div><div class="line">pod cache clean Your_Project_Name --all 清除所有的Your_Project_Name在本地的缓存</div><div class="line">pod cache clean Your_Project_Name 会显示出所有的Your_Project_Name缓存，然后再根据你想要的去清除</div></pre></td></tr></table></figure></p><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div></pre></td><td class="code"><pre><div class="line">pod repo 管理仓库的命令</div><div class="line">pod repo update 更新本地所有仓库</div><div class="line">pod repo update [Name] 仅仅更新Name仓库</div><div class="line">pod repo push [Name.podspec] [本地仓库名字] 推送一个私有项目的配置文件podspec 到制定的私有仓库</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">pod trunk 将项目配置推送到公共的master仓库</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">pod outdated</div><div class="line">官方说法:Show outdated project dependencies</div><div class="line">解释:分析现有的依赖项，并与最新的比较。如图所示</div></pre></td></tr></table></figure><p>###运行不同版本的pod前提是你本地有不同版本的pod<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">pod _1.0.1_ install</div></pre></td></tr></table></figure></p><h1 id="0x00-Pod插件"><a href="#0x00-Pod插件" class="headerlink" title="0x00 Pod插件"></a>0x00 Pod插件</h1><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">gem install cocoapods-package 安装用来打包成静态库的插件</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">pod package [Name.podspec] [Options]</div></pre></td></tr></table></figure><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line">--force 替换本地已有的文件</div><div class="line">--no-mangle 接触Pod中已有的依赖冠以</div><div class="line">--library 打包成.a静态库</div><div class="line">--exclude-deps 不把依赖项打包进入项目</div><div class="line">--spec-sources=private,https://github.com/CocoaPods/Specs.git 如果项目中有私有源一定要加上这个</div></pre></td></tr></table></figure>]]></content>
<summary type="html">
<h1 id="0x00-Pod基础"><a href="#0x00-Pod基础" class="headerlink" title="0x00 Pod基础"></a>0x00 Pod基础</h1><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">pod --help 这个可以用来所有的命令</div></pre></td></tr></table></figure>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">$ pod [Commond] [Options]</div><div class="line">$ pod install --verbose --no-repo-update</div></pre></td></tr></table></figure>
</summary>
<category term="Cocoapods" scheme="http://www.zhz.io/tags/Cocoapods/"/>
</entry>
<entry>
<title>Share Keychain Access</title>
<link href="http://www.zhz.io/2016/08/25/Shared%20Keychain%20Access/"/>
<id>http://www.zhz.io/2016/08/25/Shared Keychain Access/</id>
<published>2016-08-25T08:57:23.000Z</published>
<updated>2016-12-15T10:04:43.000Z</updated>
<content type="html"><![CDATA[<h2 id="0x00-什么是Keychain"><a href="#0x00-什么是Keychain" class="headerlink" title="0x00 什么是Keychain"></a>0x00 什么是Keychain</h2><p>据介绍，Keychain是iOS系统官方提供的安全存储容器，我们可以用它来存一些敏感信息，EG:密码，用户名，证书等等。<br>Mac电脑上自带的Keychain Access.app就是苹果自己的Keychain读取软件。<br>Keychain是保存在沙盒之外的数据库的，所以在删除App后，在重新下载App后，这些信息依旧存在，并且你可以通过设置一些属性，让你的数据保#####存到iCloud中，达到跨设备存储。</p><h2 id="0x01-Keychain本质是什么"><a href="#0x01-Keychain本质是什么" class="headerlink" title="0x01 Keychain本质是什么"></a>0x01 Keychain本质是什么</h2><p>Keychain存储本质是Sqlite。真机地址：/private/var/Keychains/keychain-2.db<br>既然是Sqlite，那么Keychain存储的对象（后面统称为Item），即对应Sqlite上的一条记录而已。</p><a id="more"></a><h2 id="0x02-Item"><a href="#0x02-Item" class="headerlink" title="0x02 Item"></a>0x02 Item</h2><p>Item 结构</p><ul><li>Class -> kSecClass //指向对应的表结构</li><li>Attributes -> kSecAttrXXXX //每个表中对应的字段</li><li>Value -> kSecValueXXX //存储的类型</li></ul><p>Class<br>有Sqlite，那么就会有对应的表。<br>Item在保存对象的时候，你需要指定你要保存的表。</p><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">extern</span> <span class="keyword">const</span> <span class="built_in">CFStringRef</span> kSecClassGenericPassword <span class="comment">//一般的密码存储表，基本用这个为主，对应genp表</span></div><div class="line"><span class="keyword">extern</span> <span class="keyword">const</span> <span class="built_in">CFStringRef</span> kSecClassInternetPassword <span class="comment">//用来存储网络密码的表，对应inet表</span></div><div class="line"><span class="keyword">extern</span> <span class="keyword">const</span> <span class="built_in">CFStringRef</span> kSecClassCertificate <span class="comment">//用来存储证书表，对应cert表</span></div><div class="line"><span class="keyword">extern</span> <span class="keyword">const</span> <span class="built_in">CFStringRef</span> kSecClassKey <span class="comment">//存一些Key之类的东西，对应keys表</span></div><div class="line"><span class="keyword">extern</span> <span class="keyword">const</span> <span class="built_in">CFStringRef</span> kSecClassIdentity <span class="comment">//一些特殊的认证信息之类的，这个不知道。</span></div></pre></td></tr></table></figure><p>Attributes<br>关于Item的属性，对应的不同表是不同的。每个都介绍不现实，讲讲最常用的kSecClassGenericPassword表中的一些字段吧</p><table><thead><tr><th>属性</th><th>Value值</th><th>作用</th></tr></thead><tbody><tr><td>kSecAttrAccessible</td><td>kSecAttrAccessibleWhenUnlocked （Default）</td><td>你能获取到Keychain的数据必须在设备被解锁的情况下获取</td></tr><tr><td></td><td>kSecAttrAccessibleAfterFirstUnlock</td><td>Keychain的数据在设备第一次解锁之后就能够获取使用</td></tr><tr><td></td><td>kSecAttrAccessibleAlways</td><td>Keychain数据始终可以获取到</td></tr><tr><td>kSecAttrAccessGroup</td><td>自定义Like（@”AppIdentifierPrefix.com.hongzhi.test”）</td><td>设置你的存储区域，后面会详细讲</td></tr><tr><td>kSecAttrAccount</td><td>自定义</td><td>标识此条数据的主Key之一</td></tr><tr><td>kSecAttrService</td><td>自定义</td><td>标识此条数据的主Key之一</td></tr><tr><td>kSecAttrGeneric</td><td>自定义</td><td>非主键用来标识</td></tr><tr><td>kSecAttrSynchronizable</td><td>BOOL</td><td>标识是否同步到iCloud</td></tr></tbody></table><blockquote><p>Note:<br> kSecAttrAccessible还有另外三种是在上面这几个后面加ThisDeviceOnly，则数据不会跟随设备移动，会跟设备绑定。<br><br> AppIdentifierPrefix是你开发证书的唯一标识符号，com.hongzhi.test是你应用的BundleId。</p></blockquote><p>Value</p><table><thead><tr><th>属性</th><th>Value值</th><th>作用</th></tr></thead><tbody><tr><td>kSecValueData</td><td>Get或者Set</td><td>这个就是你要存数据的Value，只能存NSData对象</td></tr></tbody></table><h2 id="0x03-用法"><a href="#0x03-用法" class="headerlink" title="0x03 用法"></a>0x03 用法</h2><p>既然是Sqlite数据库的存储，那么肯定就有增删该查。<br>每个函数都会有一个OSStatus的标识，标识操作是否成功,更多的标识参考SecBase.h文件中的OSStatus枚举值。</p><ol><li>SecItemAdd 添加一个keychain item</li><li>SecItemUpdate 修改一个keychain item</li><li>SecItemCopyMatching 搜索一个keychain item</li><li>SecItemDelete 删除一个keychain item</li></ol><figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div><div class="line">42</div><div class="line">43</div><div class="line">44</div><div class="line">45</div><div class="line">46</div><div class="line">47</div><div class="line">48</div><div class="line">49</div><div class="line">50</div><div class="line">51</div><div class="line">52</div><div class="line">53</div><div class="line">54</div><div class="line">55</div><div class="line">56</div></pre></td><td class="code"><pre><div class="line">- (<span class="built_in">NSMutableDictionary</span> *)newSearchDictionary:(<span class="built_in">NSString</span> *)identifier {</div><div class="line"> <span class="built_in">NSMutableDictionary</span> *searchDictionary = [[<span class="built_in">NSMutableDictionary</span> alloc] init];</div><div class="line"> <span class="comment">//指定item的类型为GenericPassword</span></div><div class="line"> [searchDictionary setObject:(<span class="keyword">id</span>)kSecClassGenericPassword forKey:(<span class="keyword">id</span>)kSecClass];</div><div class="line"> </div><div class="line"> <span class="comment">//类型为GenericPassword的信息必须提供以下两条属性作为unique identifier</span></div><div class="line"> [searchDictionary setObject:encodedIdentifier forKey:(<span class="keyword">id</span>)kSecAttrAccount]；</div><div class="line"> [searchDictionary setObject:encodedIdentifier forKey:(<span class="keyword">id</span>)kSecAttrService]；</div><div class="line"> </div><div class="line"> <span class="keyword">return</span> searchDictionary;</div><div class="line">}</div><div class="line">- (<span class="built_in">NSData</span> *)searchKeychainCopyMatching:(<span class="built_in">NSString</span> *)identifier {</div><div class="line"> <span class="built_in">NSMutableDictionary</span> *searchDictionary = [<span class="keyword">self</span> newSearchDictionary:identifier];</div><div class="line"> </div><div class="line"> <span class="comment">//在搜索keychain item的时候必须提供下面的两条用于搜索的属性</span></div><div class="line"> <span class="comment">//只返回搜索到的第一条item</span></div><div class="line"> [searchDictionary setObject:(<span class="keyword">id</span>)kSecMatchLimitOne forKey:(<span class="keyword">id</span>)kSecMatchLimit];</div><div class="line"> <span class="comment">//返回item的kSecValueData</span></div><div class="line"> [searchDictionary setObject:(<span class="keyword">id</span>)kCFBooleanTrue forKey:(<span class="keyword">id</span>)kSecReturnData];</div><div class="line"> </div><div class="line"> <span class="built_in">NSData</span> *result = <span class="literal">nil</span>;</div><div class="line"> OSStatus status = SecItemCopyMatching((<span class="built_in">CFDictionaryRef</span>)searchDictionary,</div><div class="line"> (<span class="built_in">CFTypeRef</span> *)&result);</div><div class="line"> <span class="keyword">return</span> result;</div><div class="line">}</div><div class="line">- (<span class="built_in">BOOL</span>)createKeychainValue:(<span class="built_in">NSString</span> *)password forIdentifier:(<span class="built_in">NSString</span> *)identifier {</div><div class="line"> <span class="comment">//设置添加的字典</span></div><div class="line"> <span class="built_in">NSMutableDictionary</span> *dictionary = [<span class="keyword">self</span> newSearchDictionary:identifier];</div><div class="line"> </div><div class="line"> <span class="built_in">NSData</span> *passwordData = [password dataUsingEncoding:<span class="built_in">NSUTF8StringEncoding</span>];</div><div class="line"> [dictionary setObject:passwordData forKey:(<span class="keyword">id</span>)kSecValueData];</div><div class="line"> </div><div class="line"> OSStatus status = SecItemAdd((<span class="built_in">CFDictionaryRef</span>)dictionary, <span class="literal">NULL</span>);</div><div class="line"> <span class="keyword">if</span> (status == errSecSuccess) {</div><div class="line"> <span class="keyword">return</span> <span class="literal">YES</span>;</div><div class="line"> }</div><div class="line"> <span class="keyword">return</span> <span class="literal">NO</span>;</div><div class="line">}</div><div class="line">- (<span class="built_in">BOOL</span>)updateKeychainValue:(<span class="built_in">NSString</span> *)password forIdentifier:(<span class="built_in">NSString</span> *)identifier {</div><div class="line"> <span class="built_in">NSMutableDictionary</span> *searchDictionary = [<span class="keyword">self</span> newSearchDictionary:identifier];</div><div class="line"> </div><div class="line"> <span class="built_in">NSMutableDictionary</span> *updateDictionary = [[<span class="built_in">NSMutableDictionary</span> alloc] init];</div><div class="line"> <span class="built_in">NSData</span> *passwordData = [password dataUsingEncoding:<span class="built_in">NSUTF8StringEncoding</span>];</div><div class="line"> [updateDictionary setObject:passwordData forKey:(<span class="keyword">id</span>)kSecValueData];</div><div class="line"> </div><div class="line"> OSStatus status = SecItemUpdate((<span class="built_in">CFDictionaryRef</span>)searchDictionary,</div><div class="line"> (<span class="built_in">CFDictionaryRef</span>)updateDictionary);</div><div class="line"> <span class="keyword">if</span> (status == errSecSuccess) {</div><div class="line"> <span class="keyword">return</span> <span class="literal">YES</span>;</div><div class="line"> }</div><div class="line"> <span class="keyword">return</span> <span class="literal">NO</span>;</div><div class="line">}</div><div class="line">- (<span class="keyword">void</span>)deleteKeychainValue:(<span class="built_in">NSString</span> *)identifier {</div><div class="line"> <span class="built_in">NSMutableDictionary</span> *searchDictionary = [<span class="keyword">self</span> newSearchDictionary:identifier];</div><div class="line"> SecItemDelete((<span class="built_in">CFDictionaryRef</span>)searchDictionary);</div><div class="line">}</div></pre></td></tr></table></figure><h2 id="0x04-关于iCloud备份"><a href="#0x04-关于iCloud备份" class="headerlink" title="0x04 关于iCloud备份"></a>0x04 关于iCloud备份</h2><ol><li>使用kSecAttrSynchronizable可以对存储的值进行跨设备的备份，但是添加这个字段后，搜索会以这个值作为主要的Key。</li><li>搜索匹配的时候要带上这个字段才能查询到相应的Item。</li></ol><h2 id="0x05-App间共享数据"><a href="#0x05-App间共享数据" class="headerlink" title="0x05 App间共享数据"></a>0x05 App间共享数据</h2><ol><li>关键东西：Keychain access group。</li><li>原理：Keychain通过Provisioning profile来区分应用，每个profile会带有相应的bundle id和添加的Access Group，应用保存的数据指定在对应的Access group中，如果没有在属性中设置，即存储在已bundle id命名的Access Group中。</li><li>非代码指定Access Group的话，就要在Capabilities中打开Keychain Sharing，在其中添加相应的BundleId，系统会自动帮你添加AppIdentifierPrefix，即Id值。<br>Use:<figure class="highlight objectivec"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">[searchDictionary setObject:@“AppIdentifierPrefix.UC.testWriteKeychainSuit” forKey:(<span class="keyword">id</span>)kSecAttrAccessGroup];</div></pre></td></tr></table></figure></li></ol><blockquote><p>如果多个App指定了同一个Access group，并且它是由同一个证书下发的，那么这两个App就能够从这个Access Group中获取数据。</p></blockquote><h2 id="0xfe-总结"><a href="#0xfe-总结" class="headerlink" title="0xfe 总结"></a>0xfe 总结</h2><p>Keychain很方便，支持App间，设备间数据的传输，为一大群开发者解决了一堆的难题，但是也不能过度依赖于这个东西。Keychain的读取速度是NSUserDefault的3倍时长左右。一些简单的数据存储在Info.plist或者NSUserdefault中反而会更好。</p><h2 id="0xff-参考链接"><a href="#0xff-参考链接" class="headerlink" title="0xff 参考链接"></a>0xff 参考链接</h2><p><a href="https://developer.apple.com/videos/play/wwdc2013/709/" target="_blank" rel="noopener">2013届WWDC Keychain简介</a><br><a href="http://blog.sheliw.com/blog/2015/02/16/keychain/" target="_blank" rel="noopener">Max Blog Keychain</a></p>]]></content>
<summary type="html">
<h2 id="0x00-什么是Keychain"><a href="#0x00-什么是Keychain" class="headerlink" title="0x00 什么是Keychain"></a>0x00 什么是Keychain</h2><p>据介绍，Keychain是iOS系统官方提供的安全存储容器，我们可以用它来存一些敏感信息，EG:密码，用户名，证书等等。<br>Mac电脑上自带的Keychain Access.app就是苹果自己的Keychain读取软件。<br>Keychain是保存在沙盒之外的数据库的，所以在删除App后，在重新下载App后，这些信息依旧存在，并且你可以通过设置一些属性，让你的数据保#####存到iCloud中，达到跨设备存储。</p>
<h2 id="0x01-Keychain本质是什么"><a href="#0x01-Keychain本质是什么" class="headerlink" title="0x01 Keychain本质是什么"></a>0x01 Keychain本质是什么</h2><p>Keychain存储本质是Sqlite。真机地址：/private/var/Keychains/keychain-2.db<br>既然是Sqlite，那么Keychain存储的对象（后面统称为Item），即对应Sqlite上的一条记录而已。</p>
</summary>
<category term="iOS" scheme="http://www.zhz.io/tags/iOS/"/>
</entry>
</feed>