php yield关键字以及协程的实现
<p>php的yield是在php5.5版本就出来了,而在初级php界却很少有人提起,我就说说个人对php yield的理解</p><p> </p>
<h1>Iterator接口</h1>
<p>在php中,除了数组,对象可以被foreach遍历之外,还有另外一种特殊对象,也就是继承了iterator接口的对象,也可以被对象遍历,但和普通对象的遍历又有所不同,下面是3种类型的遍历情况:</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535804576449137.png"><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535804607134071.png"><br><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535804699386302.png"></p>
<p> </p>
<p> </p>
<p>可以看出,迭代器的遍历,会依次调用重置,检查当前数据,返回当前指针数据,指针下移方法,结束遍历的条件在于检查数据返回true或者false</p>
<p> </p>
<p> </p>
<h1>生成器</h1>
<p>生成器和迭代器类似,但也完全不同</p>
<p>生成器允许你在 foreach 代码块中写代码来迭代一组数据而不需要在内存中创建一个数组, 那会使你的内存达到上限，或者会占据可观的处理时间。相反，你可以写一个生成器函数，就像一个普通的自定义函数一样, 和普通函数只返回一次不同的是, 生成器可以根据需要 yield 多次，以便生成需要迭代的值。</p>
<p>生成器使用yield关键字进行生成迭代的值</p>
<p> </p>
<p>例如:</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535805288845536.png"></p>
<p> </p>
<h2>一:生成器方法</h2>
<p>生成器它的内部实现了以下方法:</p>
<p>Generator implements Iterator { <span class="hljs-comment">//返回当前产生的值
<span class="hljs-keyword">public mixed current ( void ) <span class="hljs-comment">//返回当前产生的键
<span class="hljs-keyword">public mixed key ( void ) <span class="hljs-comment">//生成器继续执行
<span class="hljs-keyword">public void next ( void ) <span class="hljs-comment">//重置迭代器,如果迭代已经开始了，这里会抛出一个异常。
<span class="hljs-keyword">public void rewind ( void ) <span class="hljs-comment">//向生成器中传入一个值，当前yield接收值，然后继续执行下一个yield
<span class="hljs-keyword">public mixed send ( mixed <span class="hljs-variable">$value ) <span class="hljs-comment">//向生成器中抛入一个异常
<span class="hljs-keyword">public void <span class="hljs-keyword">throw ( <span class="hljs-keyword">Exception <span class="hljs-variable">$exception ) <span class="hljs-comment">//检查迭代器是否被关闭,已被关闭返回 FALSE，否则返回 TRUE
<span class="hljs-keyword">public bool valid ( void ) <span class="hljs-comment">//序列化回调
<span class="hljs-keyword">public void __wakeup ( void ) <span class="hljs-comment">//返回generator函数的返回值，PHP version 7+
<span class="hljs-keyword">public mixed getReturn ( void )
}</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></p>
<h2>二:语法</h2>
<p>生成器的语法有很多种用法,需要一一说明,首先,yield必须有函数包裹,包裹yield的函数称为"生成器函数",该函数将返回一个可遍历的对象</p>
<p> </p>
<h3>1:颠覆常识的yield</h3>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535806719496494.png"></p>
<p> </p>
<p>可能你在这发现了几个东西,和之前php完全不同的认知,如果你没发现,额,那我提出来吧</p>
<p>1:在调用函数返回的时候,可以发现for里面的语句并没有执行</p>
<p>2:在遍历一次的时候,可以发现调用函数,却没有正常的for循环3次,只循环了一次</p>
<p>3:在遍历一次的情况时,"存在感2"竟然没有调用,在一直遍历的情况下才调用</p>
<p> </p>
<p>再看看另一个例子:</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535807821192192.png"></p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535807811935794.png"></p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535807878766060.png"></p>
<p> </p>
<p> </p>
<p>什么????while(ture)竟然还能正常的执行下去???没错,生成器函数就是这样的,根据这个例子,我们发现了这些东西:</p>
<p>1:while(true)没有阻塞调用函数下面的代码执行,却导致了下面的echo "额额额"和return 无法执行</p>
<p>2:return 返回值竟然是没有作用的</p>
<p>3:send(1)时,没有echo "哈哈",send(2)时,才开始出现"哈哈",</p>
<p> </p>
<h3>2:yield的其他语法</h3>
<p>yield表达式中,也可以赋值,但赋值需要使用括号包裹:</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535808541905209.png"></p>
<p> </p>
<p>只需要在表达式后面加上$key=>$value,即可生成键值的数据:</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535808790721915.png"></p>
<p> </p>
<p> </p>
<p>在函数前增加引用定义,就可以像returning references from functions（从函数返回一个引用）一样 引用生成值</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180901/1535808927318223.png"></p>
<p> </p>
<p> </p>
<p> </p>
<h2>三:特性总结</h2>
<p>1:yield是生成器所需要的关键字,必须在函数内部,有yield的函数叫做"生成器函数"</p>
<p>2:调用生成器函数时,函数将返回一个继承了Iterator的生成器</p>
<p>3:yield作为表达式使用时,可将一个值加入到生成器中进行遍历,遍历完会中断下面的语句运行,并且保存状态,当下次遍历时会继续执行(这就是while(true)没有造成阻塞的原因)</p>
<p>4:当send传入参数时,yield可作为一个变量使用,这个变量等于传入的参数</p>
<p> </p>
<h1>协程</h1>
<h2>一:实现个简单的协程</h2>
<p>协程,是一种编程逻辑的转变,使多个任务能交替运行,而不是之前的一直根据流程往下走,举个例子</p>
<p>当有一个逻辑,每次调用这个文件时,该文件要做3件事:</p>
<p>1:写入300个文件</p>
<p>2:发送邮件给500个会员</p>
<p>3:插入100条数据</p>
<p>代码:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
<div class="line number11 index10 alt2">11</div>
<div class="line number12 index11 alt1">12</div>
<div class="line number13 index12 alt2">13</div>
<div class="line number14 index13 alt1">14</div>
<div class="line number15 index14 alt2">15</div>
<div class="line number16 index15 alt1">16</div>
<div class="line number17 index16 alt2">17</div>
<div class="line number18 index17 alt1">18</div>
<div class="line number19 index18 alt2">19</div>
<div class="line number20 index19 alt1">20</div>
<div class="line number21 index20 alt2">21</div>
<div class="line number22 index21 alt1">22</div>
<div class="line number23 index22 alt2">23</div>
<div class="line number24 index23 alt1">24</div>
<div class="line number25 index24 alt2">25</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php plain"><?php</code></div>
<div class="line number2 index1 alt1"><code class="php keyword">function</code> <code class="php plain">task1(){</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php keyword">for</code> <code class="php plain">(</code><code class="php variable">$i</code><code class="php plain">=0;</code><code class="php variable">$i</code><code class="php plain"><=300;</code><code class="php variable">$i</code><code class="php plain">++){</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php comments">//写入文件,大概要3000微秒</code></div>
<div class="line number5 index4 alt2"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number6 index5 alt1"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"写入文件{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number7 index6 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number8 index7 alt1"><code class="php plain">}</code></div>
<div class="line number9 index8 alt2"><code class="php keyword">function</code> <code class="php plain">task2(){</code></div>
<div class="line number10 index9 alt1"><code class="php spaces"> </code><code class="php keyword">for</code> <code class="php plain">(</code><code class="php variable">$i</code><code class="php plain">=0;</code><code class="php variable">$i</code><code class="php plain"><=500;</code><code class="php variable">$i</code><code class="php plain">++){</code></div>
<div class="line number11 index10 alt2"><code class="php spaces"> </code><code class="php comments">//发送邮件给500名会员,大概3000微秒</code></div>
<div class="line number12 index11 alt1"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number13 index12 alt2"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"发送邮件{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number15 index14 alt2"><code class="php plain">}</code></div>
<div class="line number16 index15 alt1"><code class="php keyword">function</code> <code class="php plain">task3(){</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php keyword">for</code> <code class="php plain">(</code><code class="php variable">$i</code><code class="php plain">=0;</code><code class="php variable">$i</code><code class="php plain"><=100;</code><code class="php variable">$i</code><code class="php plain">++){</code></div>
<div class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php comments">//模拟插入100条数据,大概3000微秒</code></div>
<div class="line number19 index18 alt2"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"插入数据{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number21 index20 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number22 index21 alt1"><code class="php plain">}</code></div>
<div class="line number23 index22 alt2"><code class="php plain">task1();</code></div>
<div class="line number24 index23 alt1"><code class="php plain">task2();</code></div>
<div class="line number25 index24 alt2"><code class="php plain">task3();</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p>这样,就实现了这3个功能了,然而,技术组长又说:</p>
<p>能不能改成交替运行呢?</p>
<p>就是说,写入文件一次之后,马上去发送一次邮件,然后再去插入一条数据</p>
<p> </p>
<p>然后我改一改:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
<div class="line number11 index10 alt2">11</div>
<div class="line number12 index11 alt1">12</div>
<div class="line number13 index12 alt2">13</div>
<div class="line number14 index13 alt1">14</div>
<div class="line number15 index14 alt2">15</div>
<div class="line number16 index15 alt1">16</div>
<div class="line number17 index16 alt2">17</div>
<div class="line number18 index17 alt1">18</div>
<div class="line number19 index18 alt2">19</div>
<div class="line number20 index19 alt1">20</div>
<div class="line number21 index20 alt2">21</div>
<div class="line number22 index21 alt1">22</div>
<div class="line number23 index22 alt2">23</div>
<div class="line number24 index23 alt1">24</div>
<div class="line number25 index24 alt2">25</div>
<div class="line number26 index25 alt1">26</div>
<div class="line number27 index26 alt2">27</div>
<div class="line number28 index27 alt1">28</div>
<div class="line number29 index28 alt2">29</div>
<div class="line number30 index29 alt1">30</div>
<div class="line number31 index30 alt2">31</div>
<div class="line number32 index31 alt1">32</div>
<div class="line number33 index32 alt2">33</div>
<div class="line number34 index33 alt1">34</div>
<div class="line number35 index34 alt2">35</div>
<div class="line number36 index35 alt1">36</div>
<div class="line number37 index36 alt2">37</div>
<div class="line number38 index37 alt1">38</div>
<div class="line number39 index38 alt2">39</div>
<div class="line number40 index39 alt1">40</div>
<div class="line number41 index40 alt2">41</div>
<div class="line number42 index41 alt1">42</div>
<div class="line number43 index42 alt2">43</div>
<div class="line number44 index43 alt1">44</div>
<div class="line number45 index44 alt2">45</div>
<div class="line number46 index45 alt1">46</div>
<div class="line number47 index46 alt2">47</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php plain"><?php</code></div>
<div class="line number2 index1 alt1"><code class="php keyword">function</code> <code class="php plain">task1(</code><code class="php variable">$i</code><code class="php plain">)</code></div>
<div class="line number3 index2 alt2"><code class="php plain">{</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php comments">//使用$i标识 写入文件,大概要3000微秒</code></div>
<div class="line number5 index4 alt2"><code class="php spaces"> </code><code class="php keyword">if</code> <code class="php plain">(</code><code class="php variable">$i</code> <code class="php plain">> 300) {</code></div>
<div class="line number6 index5 alt1"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php plain">false;</code><code class="php comments">//超过300不用写了</code></div>
<div class="line number7 index6 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number8 index7 alt1"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"写入文件{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number9 index8 alt2"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number10 index9 alt1"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php plain">true;</code></div>
<div class="line number11 index10 alt2"><code class="php plain">}</code></div>
<div class="line number12 index11 alt1"> </div>
<div class="line number13 index12 alt2"><code class="php keyword">function</code> <code class="php plain">task2(</code><code class="php variable">$i</code><code class="php plain">)</code></div>
<div class="line number14 index13 alt1"><code class="php plain">{</code></div>
<div class="line number15 index14 alt2"><code class="php spaces"> </code><code class="php comments">//使用$i标识 发送邮件,大概要3000微秒</code></div>
<div class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php keyword">if</code> <code class="php plain">(</code><code class="php variable">$i</code> <code class="php plain">> 500) {</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php plain">false;</code><code class="php comments">//超过500不用发送了</code></div>
<div class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number19 index18 alt2"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"发送邮件{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number21 index20 alt2"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php plain">true;</code></div>
<div class="line number22 index21 alt1"><code class="php plain">}</code></div>
<div class="line number23 index22 alt2"> </div>
<div class="line number24 index23 alt1"><code class="php keyword">function</code> <code class="php plain">task3(</code><code class="php variable">$i</code><code class="php plain">)</code></div>
<div class="line number25 index24 alt2"><code class="php plain">{</code></div>
<div class="line number26 index25 alt1"><code class="php spaces"> </code><code class="php comments">//使用$i标识 插入数据,大概要3000微秒</code></div>
<div class="line number27 index26 alt2"><code class="php spaces"> </code><code class="php keyword">if</code> <code class="php plain">(</code><code class="php variable">$i</code> <code class="php plain">> 100) {</code></div>
<div class="line number28 index27 alt1"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php plain">false;</code><code class="php comments">//超过100不用插入</code></div>
<div class="line number29 index28 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number30 index29 alt1"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"插入数据{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number31 index30 alt2"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number32 index31 alt1"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php plain">true;</code></div>
<div class="line number33 index32 alt2"><code class="php plain">}</code></div>
<div class="line number34 index33 alt1"> </div>
<div class="line number35 index34 alt2"><code class="php variable">$i</code> <code class="php plain">= 0;</code></div>
<div class="line number36 index35 alt1"><code class="php variable">$task1Result</code> <code class="php plain">= true;</code></div>
<div class="line number37 index36 alt2"><code class="php variable">$task2Result</code> <code class="php plain">= true;</code></div>
<div class="line number38 index37 alt1"><code class="php variable">$task3Result</code> <code class="php plain">= true;</code></div>
<div class="line number39 index38 alt2"><code class="php keyword">while</code> <code class="php plain">(true) {</code></div>
<div class="line number40 index39 alt1"><code class="php spaces"> </code><code class="php variable">$task1Result</code> <code class="php plain">&& </code><code class="php variable">$task1Result</code> <code class="php plain">= task1(</code><code class="php variable">$i</code><code class="php plain">);</code></div>
<div class="line number41 index40 alt2"><code class="php spaces"> </code><code class="php variable">$task2Result</code> <code class="php plain">&& </code><code class="php variable">$task2Result</code> <code class="php plain">= task2(</code><code class="php variable">$i</code><code class="php plain">);</code></div>
<div class="line number42 index41 alt1"><code class="php spaces"> </code><code class="php variable">$task3Result</code> <code class="php plain">&& </code><code class="php variable">$task3Result</code> <code class="php plain">= task3(</code><code class="php variable">$i</code><code class="php plain">);</code></div>
<div class="line number43 index42 alt2"><code class="php spaces"> </code><code class="php keyword">if</code><code class="php plain">(</code><code class="php variable">$task1Result</code><code class="php plain">===false&&</code><code class="php variable">$task2Result</code><code class="php plain">===false&&</code><code class="php variable">$task3Result</code><code class="php plain">===false){</code></div>
<div class="line number44 index43 alt1"><code class="php spaces"> </code><code class="php keyword">break</code><code class="php plain">;</code><code class="php comments">//全部任务完成,退出循环</code></div>
<div class="line number45 index44 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number46 index45 alt1"><code class="php spaces"> </code><code class="php variable">$i</code><code class="php plain">++;</code></div>
<div class="line number47 index46 alt2"><code class="php plain">}</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p> </p>
<p>运行一下:</p>
<p>代码1:</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180902/1535861590517681.png"></p>
<p> </p>
<p>代码2:</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180902/1535861607769898.png"></p>
<p> </p>
<p>确实是实现了任务交替执行,但是代码2明显让代码变的非常的难读,扩展性也很差,那么,有没有更好的方式实现这个功能呢?</p>
<p>这时候我们就必须借助yield了</p>
<p>首先,我们得封装一个任务类:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
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</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php comments">/**</code></div>
<div class="line number2 index1 alt1"><code class="php spaces"> </code><code class="php comments">* 任务对象</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php comments">* Class Task</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number5 index4 alt2"><code class="php keyword">class</code> <code class="php plain">Task {</code></div>
<div class="line number6 index5 alt1"><code class="php spaces"> </code><code class="php keyword">protected</code> <code class="php variable">$taskId</code><code class="php plain">;</code><code class="php comments">//任务id</code></div>
<div class="line number7 index6 alt2"><code class="php spaces"> </code><code class="php keyword">protected</code> <code class="php variable">$coroutine</code><code class="php plain">;</code><code class="php comments">//生成器</code></div>
<div class="line number8 index7 alt1"><code class="php spaces"> </code><code class="php keyword">protected</code> <code class="php variable">$sendValue</code> <code class="php plain">= null;</code><code class="php comments">//生成器send值</code></div>
<div class="line number9 index8 alt2"><code class="php spaces"> </code><code class="php keyword">protected</code> <code class="php variable">$beforeFirstYield</code> <code class="php plain">= true;</code><code class="php comments">//迭代指针是否是第一个</code></div>
<div class="line number10 index9 alt1"> </div>
<div class="line number11 index10 alt2"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">__construct(</code><code class="php variable">$taskId</code><code class="php plain">, Generator </code><code class="php variable">$coroutine</code><code class="php plain">) {</code></div>
<div class="line number12 index11 alt1"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->taskId = </code><code class="php variable">$taskId</code><code class="php plain">;</code></div>
<div class="line number13 index12 alt2"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->coroutine = </code><code class="php variable">$coroutine</code><code class="php plain">;</code></div>
<div class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number15 index14 alt2"> </div>
<div class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">getTaskId() {</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php variable">$this</code><code class="php plain">->taskId;</code></div>
<div class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number19 index18 alt2"> </div>
<div class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php comments">/**</code></div>
<div class="line number21 index20 alt2"><code class="php spaces"> </code><code class="php comments">* 设置插入数据</code></div>
<div class="line number22 index21 alt1"><code class="php spaces"> </code><code class="php comments">* @param $sendValue</code></div>
<div class="line number23 index22 alt2"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number24 index23 alt1"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">setSendValue(</code><code class="php variable">$sendValue</code><code class="php plain">) {</code></div>
<div class="line number25 index24 alt2"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->sendValue = </code><code class="php variable">$sendValue</code><code class="php plain">;</code></div>
<div class="line number26 index25 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number27 index26 alt2"> </div>
<div class="line number28 index27 alt1"><code class="php spaces"> </code><code class="php comments">/**</code></div>
<div class="line number29 index28 alt2"><code class="php spaces"> </code><code class="php comments">* send数据进行迭代</code></div>
<div class="line number30 index29 alt1"><code class="php spaces"> </code><code class="php comments">* @return mixed</code></div>
<div class="line number31 index30 alt2"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number32 index31 alt1"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">run() {</code></div>
<div class="line number33 index32 alt2"><code class="php spaces"> </code><code class="php comments">//如果是</code></div>
<div class="line number34 index33 alt1"><code class="php spaces"> </code><code class="php keyword">if</code> <code class="php plain">(</code><code class="php variable">$this</code><code class="php plain">->beforeFirstYield) {</code></div>
<div class="line number35 index34 alt2"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->beforeFirstYield = false;</code></div>
<div class="line number36 index35 alt1"><code class="php spaces"> </code><code class="php plain">var_dump(</code><code class="php variable">$this</code><code class="php plain">->coroutine->current());</code></div>
<div class="line number37 index36 alt2"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php variable">$this</code><code class="php plain">->coroutine->current();</code></div>
<div class="line number38 index37 alt1"><code class="php spaces"> </code><code class="php plain">} </code><code class="php keyword">else</code> <code class="php plain">{</code></div>
<div class="line number39 index38 alt2"><code class="php spaces"> </code><code class="php variable">$retval</code> <code class="php plain">= </code><code class="php variable">$this</code><code class="php plain">->coroutine->send(</code><code class="php variable">$this</code><code class="php plain">->sendValue);</code></div>
<div class="line number40 index39 alt1"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->sendValue = null;</code></div>
<div class="line number41 index40 alt2"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php variable">$retval</code><code class="php plain">;</code></div>
<div class="line number42 index41 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number43 index42 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number44 index43 alt1"> </div>
<div class="line number45 index44 alt2"><code class="php spaces"> </code><code class="php comments">/**</code></div>
<div class="line number46 index45 alt1"><code class="php spaces"> </code><code class="php comments">* 是否完成</code></div>
<div class="line number47 index46 alt2"><code class="php spaces"> </code><code class="php comments">* @return bool</code></div>
<div class="line number48 index47 alt1"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number49 index48 alt2"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">isFinished() {</code></div>
<div class="line number50 index49 alt1"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php plain">!</code><code class="php variable">$this</code><code class="php plain">->coroutine->valid();</code></div>
<div class="line number51 index50 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number52 index51 alt1"><code class="php plain">}</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p> </p>
<p>这个封装类,可以更好的去调用运行生成器函数,但只有这个也是不够的,我们还需要一个调度任务类,来代替前面的while:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
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</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php comments">/**</code></div>
<div class="line number2 index1 alt1"><code class="php spaces"> </code><code class="php comments">* 任务调度</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php comments">* Class Scheduler</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number5 index4 alt2"><code class="php keyword">class</code> <code class="php plain">Scheduler {</code></div>
<div class="line number6 index5 alt1"><code class="php spaces"> </code><code class="php keyword">protected</code> <code class="php variable">$maxTaskId</code> <code class="php plain">= 0;</code><code class="php comments">//任务id</code></div>
<div class="line number7 index6 alt2"><code class="php spaces"> </code><code class="php keyword">protected</code> <code class="php variable">$taskMap</code> <code class="php plain">= []; </code><code class="php comments">// taskId => task</code></div>
<div class="line number8 index7 alt1"><code class="php spaces"> </code><code class="php keyword">protected</code> <code class="php variable">$taskQueue</code><code class="php plain">;</code><code class="php comments">//任务队列</code></div>
<div class="line number9 index8 alt2"> </div>
<div class="line number10 index9 alt1"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">__construct() {</code></div>
<div class="line number11 index10 alt2"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->taskQueue = </code><code class="php keyword">new</code> <code class="php plain">SplQueue();</code></div>
<div class="line number12 index11 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number13 index12 alt2"> </div>
<div class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">newTask(Generator </code><code class="php variable">$coroutine</code><code class="php plain">) {</code></div>
<div class="line number15 index14 alt2"><code class="php spaces"> </code><code class="php variable">$tid</code> <code class="php plain">= ++</code><code class="php variable">$this</code><code class="php plain">->maxTaskId;</code></div>
<div class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php comments">//新增任务</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php variable">$task</code> <code class="php plain">= </code><code class="php keyword">new</code> <code class="php plain">Task(</code><code class="php variable">$tid</code><code class="php plain">, </code><code class="php variable">$coroutine</code><code class="php plain">);</code></div>
<div class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->taskMap[</code><code class="php variable">$tid</code><code class="php plain">] = </code><code class="php variable">$task</code><code class="php plain">;</code></div>
<div class="line number19 index18 alt2"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->schedule(</code><code class="php variable">$task</code><code class="php plain">);</code></div>
<div class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php variable">$tid</code><code class="php plain">;</code></div>
<div class="line number21 index20 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number22 index21 alt1"> </div>
<div class="line number23 index22 alt2"><code class="php spaces"> </code><code class="php comments">/**</code></div>
<div class="line number24 index23 alt1"><code class="php spaces"> </code><code class="php comments">* 任务入列</code></div>
<div class="line number25 index24 alt2"><code class="php spaces"> </code><code class="php comments">* @param Task $task</code></div>
<div class="line number26 index25 alt1"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number27 index26 alt2"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">schedule(Task </code><code class="php variable">$task</code><code class="php plain">) {</code></div>
<div class="line number28 index27 alt1"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->taskQueue->enqueue(</code><code class="php variable">$task</code><code class="php plain">);</code></div>
<div class="line number29 index28 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number30 index29 alt1"> </div>
<div class="line number31 index30 alt2"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">run() {</code></div>
<div class="line number32 index31 alt1"><code class="php spaces"> </code><code class="php keyword">while</code> <code class="php plain">(!</code><code class="php variable">$this</code><code class="php plain">->taskQueue->isEmpty()) {</code></div>
<div class="line number33 index32 alt2"><code class="php spaces"> </code><code class="php comments">//任务出列进行遍历生成器数据</code></div>
<div class="line number34 index33 alt1"><code class="php spaces"> </code><code class="php variable">$task</code> <code class="php plain">= </code><code class="php variable">$this</code><code class="php plain">->taskQueue->dequeue();</code></div>
<div class="line number35 index34 alt2"><code class="php spaces"> </code><code class="php variable">$task</code><code class="php plain">->run();</code></div>
<div class="line number36 index35 alt1"> </div>
<div class="line number37 index36 alt2"><code class="php spaces"> </code><code class="php keyword">if</code> <code class="php plain">(</code><code class="php variable">$task</code><code class="php plain">->isFinished()) {</code></div>
<div class="line number38 index37 alt1"><code class="php spaces"> </code><code class="php comments">//完成则删除该任务</code></div>
<div class="line number39 index38 alt2"><code class="php spaces"> </code><code class="php plain">unset(</code><code class="php variable">$this</code><code class="php plain">->taskMap[</code><code class="php variable">$task</code><code class="php plain">->getTaskId()]);</code></div>
<div class="line number40 index39 alt1"><code class="php spaces"> </code><code class="php plain">} </code><code class="php keyword">else</code> <code class="php plain">{</code></div>
<div class="line number41 index40 alt2"><code class="php spaces"> </code><code class="php comments">//继续入列</code></div>
<div class="line number42 index41 alt1"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->schedule(</code><code class="php variable">$task</code><code class="php plain">);</code></div>
<div class="line number43 index42 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number44 index43 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number45 index44 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number46 index45 alt1"><code class="php plain">}</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p> </p>
<p>很好,我们已经有了一个调度类,还有了一个任务类,可以继续实现上面的功能了:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
<div class="line number11 index10 alt2">11</div>
<div class="line number12 index11 alt1">12</div>
<div class="line number13 index12 alt2">13</div>
<div class="line number14 index13 alt1">14</div>
<div class="line number15 index14 alt2">15</div>
<div class="line number16 index15 alt1">16</div>
<div class="line number17 index16 alt2">17</div>
<div class="line number18 index17 alt1">18</div>
<div class="line number19 index18 alt2">19</div>
<div class="line number20 index19 alt1">20</div>
<div class="line number21 index20 alt2">21</div>
<div class="line number22 index21 alt1">22</div>
<div class="line number23 index22 alt2">23</div>
<div class="line number24 index23 alt1">24</div>
<div class="line number25 index24 alt2">25</div>
<div class="line number26 index25 alt1">26</div>
<div class="line number27 index26 alt2">27</div>
<div class="line number28 index27 alt1">28</div>
<div class="line number29 index28 alt2">29</div>
<div class="line number30 index29 alt1">30</div>
<div class="line number31 index30 alt2">31</div>
<div class="line number32 index31 alt1">32</div>
<div class="line number33 index32 alt2">33</div>
<div class="line number34 index33 alt1">34</div>
<div class="line number35 index34 alt2">35</div>
<div class="line number36 index35 alt1">36</div>
<div class="line number37 index36 alt2">37</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php keyword">function</code> <code class="php plain">task1()</code></div>
<div class="line number2 index1 alt1"><code class="php plain">{</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php keyword">for</code> <code class="php plain">(</code><code class="php variable">$i</code> <code class="php plain">= 0; </code><code class="php variable">$i</code> <code class="php plain"><= 300; </code><code class="php variable">$i</code><code class="php plain">++) {</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php comments">//写入文件,大概要3000微秒</code></div>
<div class="line number5 index4 alt2"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number6 index5 alt1"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"写入文件{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number7 index6 alt2"><code class="php spaces"> </code><code class="php plain">yield </code><code class="php variable">$i</code><code class="php plain">;</code></div>
<div class="line number8 index7 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number9 index8 alt2"><code class="php plain">}</code></div>
<div class="line number10 index9 alt1"> </div>
<div class="line number11 index10 alt2"><code class="php keyword">function</code> <code class="php plain">task2()</code></div>
<div class="line number12 index11 alt1"><code class="php plain">{</code></div>
<div class="line number13 index12 alt2"><code class="php spaces"> </code><code class="php keyword">for</code> <code class="php plain">(</code><code class="php variable">$i</code> <code class="php plain">= 0; </code><code class="php variable">$i</code> <code class="php plain"><= 500; </code><code class="php variable">$i</code><code class="php plain">++) {</code></div>
<div class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php comments">//发送邮件给500名会员,大概3000微秒</code></div>
<div class="line number15 index14 alt2"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"发送邮件{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php plain">yield </code><code class="php variable">$i</code><code class="php plain">;</code></div>
<div class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number19 index18 alt2"><code class="php plain">}</code></div>
<div class="line number20 index19 alt1"> </div>
<div class="line number21 index20 alt2"><code class="php keyword">function</code> <code class="php plain">task3()</code></div>
<div class="line number22 index21 alt1"><code class="php plain">{</code></div>
<div class="line number23 index22 alt2"><code class="php spaces"> </code><code class="php keyword">for</code> <code class="php plain">(</code><code class="php variable">$i</code> <code class="php plain">= 0; </code><code class="php variable">$i</code> <code class="php plain"><= 100; </code><code class="php variable">$i</code><code class="php plain">++) {</code></div>
<div class="line number24 index23 alt1"><code class="php spaces"> </code><code class="php comments">//模拟插入100条数据,大概3000微秒</code></div>
<div class="line number25 index24 alt2"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number26 index25 alt1"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"插入数据{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number27 index26 alt2"><code class="php spaces"> </code><code class="php plain">yield </code><code class="php variable">$i</code><code class="php plain">;</code></div>
<div class="line number28 index27 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number29 index28 alt2"><code class="php plain">}</code></div>
<div class="line number30 index29 alt1"> </div>
<div class="line number31 index30 alt2"><code class="php variable">$scheduler</code> <code class="php plain">= </code><code class="php keyword">new</code> <code class="php plain">Scheduler;</code></div>
<div class="line number32 index31 alt1"> </div>
<div class="line number33 index32 alt2"><code class="php variable">$scheduler</code><code class="php plain">->newTask(task1());</code></div>
<div class="line number34 index33 alt1"><code class="php variable">$scheduler</code><code class="php plain">->newTask(task2());</code></div>
<div class="line number35 index34 alt2"><code class="php variable">$scheduler</code><code class="php plain">->newTask(task3());</code></div>
<div class="line number36 index35 alt1"> </div>
<div class="line number37 index36 alt2"><code class="php variable">$scheduler</code><code class="php plain">->run();</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p> </p>
<p>除了上面的2个类,task函数和代码1不同的地方,就是多了个yield,那我们试着运行一下:</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180902/1535872871245262.png"></p>
<p> </p>
<p>很好,我们已经实现了可以调度任务,进行任务交叉运行的功能了,这就是"协程"</p>
<p>协程可以将多个不同的任务交叉运行</p>
<p> </p>
<h2>二:协程与调度器的通信</h2>
<p>我们在上面已经实现了一个协程封装了,但是任务和调度器缺少了通信,我们可以重新封装下,使协程当中能够获取当前的任务id,新增任务,以及杀死任务</p>
<p>先封装一下调用的封装:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
<div class="line number11 index10 alt2">11</div>
<div class="line number12 index11 alt1">12</div>
<div class="line number13 index12 alt2">13</div>
<div class="line number14 index13 alt1">14</div>
<div class="line number15 index14 alt2">15</div>
<div class="line number16 index15 alt1">16</div>
<div class="line number17 index16 alt2">17</div>
<div class="line number18 index17 alt1">18</div>
<div class="line number19 index18 alt2">19</div>
<div class="line number20 index19 alt1">20</div>
<div class="line number21 index20 alt2">21</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php keyword">class</code> <code class="php plain">YieldCall</code></div>
<div class="line number2 index1 alt1"><code class="php plain">{</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php keyword">protected</code> <code class="php variable">$callback</code><code class="php plain">;</code></div>
<div class="line number4 index3 alt1"> </div>
<div class="line number5 index4 alt2"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">__construct(callable </code><code class="php variable">$callback</code><code class="php plain">)</code></div>
<div class="line number6 index5 alt1"><code class="php spaces"> </code><code class="php plain">{</code></div>
<div class="line number7 index6 alt2"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->callback = </code><code class="php variable">$callback</code><code class="php plain">;</code></div>
<div class="line number8 index7 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number9 index8 alt2"> </div>
<div class="line number10 index9 alt1"><code class="php spaces"> </code><code class="php comments">/**</code></div>
<div class="line number11 index10 alt2"><code class="php spaces"> </code><code class="php comments">* 调用时将返回结果</code></div>
<div class="line number12 index11 alt1"><code class="php spaces"> </code><code class="php comments">* @param Task $task</code></div>
<div class="line number13 index12 alt2"><code class="php spaces"> </code><code class="php comments">* @param Scheduler $scheduler</code></div>
<div class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php comments">* @return mixed</code></div>
<div class="line number15 index14 alt2"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">__invoke(Task </code><code class="php variable">$task</code><code class="php plain">, Scheduler </code><code class="php variable">$scheduler</code><code class="php plain">)</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php plain">{</code></div>
<div class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php variable">$callback</code> <code class="php plain">= </code><code class="php variable">$this</code><code class="php plain">->callback;</code></div>
<div class="line number19 index18 alt2"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php variable">$callback</code><code class="php plain">(</code><code class="php variable">$task</code><code class="php plain">, </code><code class="php variable">$scheduler</code><code class="php plain">);</code></div>
<div class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number21 index20 alt2"><code class="php plain">}</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p>同时我们需要小小的改动下调度器的run方法:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
<div class="line number11 index10 alt2">11</div>
<div class="line number12 index11 alt1">12</div>
<div class="line number13 index12 alt2">13</div>
<div class="line number14 index13 alt1">14</div>
<div class="line number15 index14 alt2">15</div>
<div class="line number16 index15 alt1">16</div>
<div class="line number17 index16 alt2">17</div>
<div class="line number18 index17 alt1">18</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">run()</code></div>
<div class="line number2 index1 alt1"><code class="php plain">{</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php keyword">while</code> <code class="php plain">(!</code><code class="php variable">$this</code><code class="php plain">->taskQueue->isEmpty()) {</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php variable">$task</code> <code class="php plain">= </code><code class="php variable">$this</code><code class="php plain">->taskQueue->dequeue();</code></div>
<div class="line number5 index4 alt2"><code class="php spaces"> </code><code class="php variable">$retval</code> <code class="php plain">= </code><code class="php variable">$task</code><code class="php plain">->run();</code></div>
<div class="line number6 index5 alt1"> </div>
<div class="line number7 index6 alt2"><code class="php spaces"> </code><code class="php comments">//如果返回的是YieldCall实例,则先执行</code></div>
<div class="line number8 index7 alt1"><code class="php spaces"> </code><code class="php keyword">if</code> <code class="php plain">(</code><code class="php variable">$retval</code> <code class="php keyword">instanceof</code> <code class="php plain">YieldCall) {</code></div>
<div class="line number9 index8 alt2"><code class="php spaces"> </code><code class="php variable">$retval</code><code class="php plain">(</code><code class="php variable">$task</code><code class="php plain">, </code><code class="php variable">$this</code><code class="php plain">);</code></div>
<div class="line number10 index9 alt1"><code class="php spaces"> </code><code class="php keyword">continue</code><code class="php plain">;</code></div>
<div class="line number11 index10 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number12 index11 alt1"><code class="php spaces"> </code><code class="php keyword">if</code> <code class="php plain">(</code><code class="php variable">$task</code><code class="php plain">->isFinished()) {</code></div>
<div class="line number13 index12 alt2"><code class="php spaces"> </code><code class="php plain">unset(</code><code class="php variable">$this</code><code class="php plain">->taskMap[</code><code class="php variable">$task</code><code class="php plain">->getTaskId()]);</code></div>
<div class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php plain">} </code><code class="php keyword">else</code> <code class="php plain">{</code></div>
<div class="line number15 index14 alt2"><code class="php spaces"> </code><code class="php variable">$this</code><code class="php plain">->schedule(</code><code class="php variable">$task</code><code class="php plain">);</code></div>
<div class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number18 index17 alt1"><code class="php plain">}</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p> </p>
<p>新增 getTaskId函数去返回task_id:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
<div class="line number11 index10 alt2">11</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php keyword">function</code> <code class="php plain">getTaskId()</code></div>
<div class="line number2 index1 alt1"><code class="php plain">{</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php comments">//返回一个YieldCall的实例</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php keyword">new</code> <code class="php plain">YieldCall(</code></div>
<div class="line number5 index4 alt2"><code class="php spaces"> </code><code class="php comments">//该匿名函数会先获取任务id,然后send给生成器,并且由YieldCall将task_id返回给生成器函数</code></div>
<div class="line number6 index5 alt1"><code class="php spaces"> </code><code class="php keyword">function</code> <code class="php plain">(Task </code><code class="php variable">$task</code><code class="php plain">, Scheduler </code><code class="php variable">$scheduler</code><code class="php plain">) {</code></div>
<div class="line number7 index6 alt2"><code class="php spaces"> </code><code class="php variable">$task</code><code class="php plain">->setSendValue(</code><code class="php variable">$task</code><code class="php plain">->getTaskId());</code></div>
<div class="line number8 index7 alt1"><code class="php spaces"> </code><code class="php variable">$scheduler</code><code class="php plain">->schedule(</code><code class="php variable">$task</code><code class="php plain">);</code></div>
<div class="line number9 index8 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number10 index9 alt1"><code class="php spaces"> </code><code class="php plain">);</code></div>
<div class="line number11 index10 alt2"><code class="php plain">}</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p>然后,我们再修改下task1,task2,task3函数:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
<div class="line number11 index10 alt2">11</div>
<div class="line number12 index11 alt1">12</div>
<div class="line number13 index12 alt2">13</div>
<div class="line number14 index13 alt1">14</div>
<div class="line number15 index14 alt2">15</div>
<div class="line number16 index15 alt1">16</div>
<div class="line number17 index16 alt2">17</div>
<div class="line number18 index17 alt1">18</div>
<div class="line number19 index18 alt2">19</div>
<div class="line number20 index19 alt1">20</div>
<div class="line number21 index20 alt2">21</div>
<div class="line number22 index21 alt1">22</div>
<div class="line number23 index22 alt2">23</div>
<div class="line number24 index23 alt1">24</div>
<div class="line number25 index24 alt2">25</div>
<div class="line number26 index25 alt1">26</div>
<div class="line number27 index26 alt2">27</div>
<div class="line number28 index27 alt1">28</div>
<div class="line number29 index28 alt2">29</div>
<div class="line number30 index29 alt1">30</div>
<div class="line number31 index30 alt2">31</div>
<div class="line number32 index31 alt1">32</div>
<div class="line number33 index32 alt2">33</div>
<div class="line number34 index33 alt1">34</div>
<div class="line number35 index34 alt2">35</div>
<div class="line number36 index35 alt1">36</div>
<div class="line number37 index36 alt2">37</div>
<div class="line number38 index37 alt1">38</div>
<div class="line number39 index38 alt2">39</div>
<div class="line number40 index39 alt1">40</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php keyword">function</code> <code class="php plain">task1()</code></div>
<div class="line number2 index1 alt1"><code class="php plain">{</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php variable">$task_id</code> <code class="php plain">= (yield getTaskId());</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php keyword">for</code> <code class="php plain">(</code><code class="php variable">$i</code> <code class="php plain">= 0; </code><code class="php variable">$i</code> <code class="php plain"><= 300; </code><code class="php variable">$i</code><code class="php plain">++) {</code></div>
<div class="line number5 index4 alt2"><code class="php spaces"> </code><code class="php comments">//写入文件,大概要3000微秒</code></div>
<div class="line number6 index5 alt1"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number7 index6 alt2"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"任务{$task_id}写入文件{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number8 index7 alt1"><code class="php spaces"> </code><code class="php plain">yield </code><code class="php variable">$i</code><code class="php plain">;</code></div>
<div class="line number9 index8 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number10 index9 alt1"><code class="php plain">}</code></div>
<div class="line number11 index10 alt2"> </div>
<div class="line number12 index11 alt1"><code class="php keyword">function</code> <code class="php plain">task2()</code></div>
<div class="line number13 index12 alt2"><code class="php plain">{</code></div>
<div class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php variable">$task_id</code> <code class="php plain">= (yield getTaskId());</code></div>
<div class="line number15 index14 alt2"><code class="php spaces"> </code><code class="php keyword">for</code> <code class="php plain">(</code><code class="php variable">$i</code> <code class="php plain">= 0; </code><code class="php variable">$i</code> <code class="php plain"><= 500; </code><code class="php variable">$i</code><code class="php plain">++) {</code></div>
<div class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php comments">//发送邮件给500名会员,大概3000微秒</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"任务{$task_id}发送邮件{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number19 index18 alt2"><code class="php spaces"> </code><code class="php plain">yield </code><code class="php variable">$i</code><code class="php plain">;</code></div>
<div class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number21 index20 alt2"><code class="php plain">}</code></div>
<div class="line number22 index21 alt1"> </div>
<div class="line number23 index22 alt2"><code class="php keyword">function</code> <code class="php plain">task3()</code></div>
<div class="line number24 index23 alt1"><code class="php plain">{</code></div>
<div class="line number25 index24 alt2"><code class="php spaces"> </code><code class="php variable">$task_id</code> <code class="php plain">= (yield getTaskId());</code></div>
<div class="line number26 index25 alt1"><code class="php spaces"> </code><code class="php keyword">for</code> <code class="php plain">(</code><code class="php variable">$i</code> <code class="php plain">= 0; </code><code class="php variable">$i</code> <code class="php plain"><= 100; </code><code class="php variable">$i</code><code class="php plain">++) {</code></div>
<div class="line number27 index26 alt2"><code class="php spaces"> </code><code class="php comments">//模拟插入100条数据,大概3000微秒</code></div>
<div class="line number28 index27 alt1"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number29 index28 alt2"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"任务{$task_id}插入数据{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number30 index29 alt1"><code class="php spaces"> </code><code class="php plain">yield </code><code class="php variable">$i</code><code class="php plain">;</code></div>
<div class="line number31 index30 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number32 index31 alt1"><code class="php plain">}</code></div>
<div class="line number33 index32 alt2"> </div>
<div class="line number34 index33 alt1"><code class="php variable">$scheduler</code> <code class="php plain">= </code><code class="php keyword">new</code> <code class="php plain">Scheduler;</code></div>
<div class="line number35 index34 alt2"> </div>
<div class="line number36 index35 alt1"><code class="php variable">$scheduler</code><code class="php plain">->newTask(task1());</code></div>
<div class="line number37 index36 alt2"><code class="php variable">$scheduler</code><code class="php plain">->newTask(task2());</code></div>
<div class="line number38 index37 alt1"><code class="php variable">$scheduler</code><code class="php plain">->newTask(task3());</code></div>
<div class="line number39 index38 alt2"> </div>
<div class="line number40 index39 alt1"><code class="php variable">$scheduler</code><code class="php plain">->run();</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p>执行结果:</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180902/1535876181780759.png"></p>
<p> </p>
<p>这样的话,当第一次执行的时候,会先调用getTaskId将task_id返回,然后将任务继续执行,这样,我们就获取到了调度器分配给任务的task_id,是不是很神奇?</p>
<p> </p>
<h2>三:生成新任务以及杀死任务</h2>
<p>现在新增了一个需求:当发送邮件给会员时,需要新增一个发送短信的子任务,当会员id大于200时则停止 (别问我为什么要这样做,我自己都不知道)</p>
<p> </p>
<p> </p>
<p>同时,我们可以利用YieldCall,去新增任务和杀死任务:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
<div class="line number11 index10 alt2">11</div>
<div class="line number12 index11 alt1">12</div>
<div class="line number13 index12 alt2">13</div>
<div class="line number14 index13 alt1">14</div>
<div class="line number15 index14 alt2">15</div>
<div class="line number16 index15 alt1">16</div>
<div class="line number17 index16 alt2">17</div>
<div class="line number18 index17 alt1">18</div>
<div class="line number19 index18 alt2">19</div>
<div class="line number20 index19 alt1">20</div>
<div class="line number21 index20 alt2">21</div>
<div class="line number22 index21 alt1">22</div>
<div class="line number23 index22 alt2">23</div>
<div class="line number24 index23 alt1">24</div>
<div class="line number25 index24 alt2">25</div>
<div class="line number26 index25 alt1">26</div>
<div class="line number27 index26 alt2">27</div>
<div class="line number28 index27 alt1">28</div>
<div class="line number29 index28 alt2">29</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php comments">/**</code></div>
<div class="line number2 index1 alt1"><code class="php spaces"> </code><code class="php comments">* 传入一个生成器函数用于新增任务给调度器调用</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php comments">* @param Generator $coroutine</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php comments">* @return YieldCall</code></div>
<div class="line number5 index4 alt2"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number6 index5 alt1"><code class="php keyword">function</code> <code class="php plain">newTask(Generator </code><code class="php variable">$coroutine</code><code class="php plain">) {</code></div>
<div class="line number7 index6 alt2"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php keyword">new</code> <code class="php plain">YieldCall(</code></div>
<div class="line number8 index7 alt1"><code class="php spaces"> </code><code class="php comments">//该匿名函数,会在调度器中新增一个任务</code></div>
<div class="line number9 index8 alt2"><code class="php spaces"> </code><code class="php keyword">function</code><code class="php plain">(Task </code><code class="php variable">$task</code><code class="php plain">, Scheduler </code><code class="php variable">$scheduler</code><code class="php plain">) </code><code class="php keyword">use</code> <code class="php plain">(</code><code class="php variable">$coroutine</code><code class="php plain">) {</code></div>
<div class="line number10 index9 alt1"><code class="php spaces"> </code><code class="php variable">$task</code><code class="php plain">->setSendValue(</code><code class="php variable">$scheduler</code><code class="php plain">->newTask(</code><code class="php variable">$coroutine</code><code class="php plain">));</code></div>
<div class="line number11 index10 alt2"><code class="php spaces"> </code><code class="php variable">$scheduler</code><code class="php plain">->schedule(</code><code class="php variable">$task</code><code class="php plain">);</code></div>
<div class="line number12 index11 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number13 index12 alt2"><code class="php spaces"> </code><code class="php plain">);</code></div>
<div class="line number14 index13 alt1"><code class="php plain">}</code></div>
<div class="line number15 index14 alt2"> </div>
<div class="line number16 index15 alt1"><code class="php comments">/**</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php comments">* 杀死一个任务</code></div>
<div class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php comments">* @param $tid</code></div>
<div class="line number19 index18 alt2"><code class="php spaces"> </code><code class="php comments">* @return YieldCall</code></div>
<div class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number21 index20 alt2"><code class="php keyword">function</code> <code class="php plain">killTask(</code><code class="php variable">$taskId</code><code class="php plain">) {</code></div>
<div class="line number22 index21 alt1"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php keyword">new</code> <code class="php plain">YieldCall(</code></div>
<div class="line number23 index22 alt2"><code class="php spaces"> </code><code class="php comments">//该匿名函数,传入一个任务id,然后让调度器去杀死该任务</code></div>
<div class="line number24 index23 alt1"><code class="php spaces"> </code><code class="php keyword">function</code><code class="php plain">(Task </code><code class="php variable">$task</code><code class="php plain">, Scheduler </code><code class="php variable">$scheduler</code><code class="php plain">) </code><code class="php keyword">use</code> <code class="php plain">(</code><code class="php variable">$taskId</code><code class="php plain">) {</code></div>
<div class="line number25 index24 alt2"><code class="php spaces"> </code><code class="php variable">$task</code><code class="php plain">->setSendValue(</code><code class="php variable">$scheduler</code><code class="php plain">->killTask(</code><code class="php variable">$taskId</code><code class="php plain">));</code></div>
<div class="line number26 index25 alt1"><code class="php spaces"> </code><code class="php variable">$scheduler</code><code class="php plain">->schedule(</code><code class="php variable">$task</code><code class="php plain">);</code></div>
<div class="line number27 index26 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number28 index27 alt1"><code class="php spaces"> </code><code class="php plain">);</code></div>
<div class="line number29 index28 alt2"><code class="php plain">}</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p>同时,调度器也得有killTask的方法:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
<div class="line number11 index10 alt2">11</div>
<div class="line number12 index11 alt1">12</div>
<div class="line number13 index12 alt2">13</div>
<div class="line number14 index13 alt1">14</div>
<div class="line number15 index14 alt2">15</div>
<div class="line number16 index15 alt1">16</div>
<div class="line number17 index16 alt2">17</div>
<div class="line number18 index17 alt1">18</div>
<div class="line number19 index18 alt2">19</div>
<div class="line number20 index19 alt1">20</div>
<div class="line number21 index20 alt2">21</div>
<div class="line number22 index21 alt1">22</div>
<div class="line number23 index22 alt2">23</div>
<div class="line number24 index23 alt1">24</div>
<div class="line number25 index24 alt2">25</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php comments">/**</code></div>
<div class="line number2 index1 alt1"><code class="php spaces"> </code><code class="php comments">* 杀死一个任务</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php comments">* @param $taskId</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php comments">* @return bool</code></div>
<div class="line number5 index4 alt2"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number6 index5 alt1"><code class="php keyword">public</code> <code class="php keyword">function</code> <code class="php plain">killTask(</code><code class="php variable">$taskId</code><code class="php plain">)</code></div>
<div class="line number7 index6 alt2"><code class="php plain">{</code></div>
<div class="line number8 index7 alt1"><code class="php spaces"> </code><code class="php keyword">if</code> <code class="php plain">(!isset(</code><code class="php variable">$this</code><code class="php plain">->taskMap[</code><code class="php variable">$taskId</code><code class="php plain">])) {</code></div>
<div class="line number9 index8 alt2"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php plain">false;</code></div>
<div class="line number10 index9 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number11 index10 alt2"> </div>
<div class="line number12 index11 alt1"><code class="php spaces"> </code><code class="php plain">unset(</code><code class="php variable">$this</code><code class="php plain">->taskMap[</code><code class="php variable">$taskId</code><code class="php plain">]);</code></div>
<div class="line number13 index12 alt2"> </div>
<div class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php comments">/**</code></div>
<div class="line number15 index14 alt2"><code class="php spaces"> </code><code class="php comments">* 遍历队列,找出id相同的则删除</code></div>
<div class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php comments">*/</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php keyword">foreach</code> <code class="php plain">(</code><code class="php variable">$this</code><code class="php plain">->taskQueue </code><code class="php keyword">as</code> <code class="php variable">$i</code> <code class="php plain">=> </code><code class="php variable">$task</code><code class="php plain">) {</code></div>
<div class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php keyword">if</code> <code class="php plain">(</code><code class="php variable">$task</code><code class="php plain">->getTaskId() === </code><code class="php variable">$taskId</code><code class="php plain">) {</code></div>
<div class="line number19 index18 alt2"><code class="php spaces"> </code><code class="php plain">unset(</code><code class="php variable">$this</code><code class="php plain">->taskQueue[</code><code class="php variable">$i</code><code class="php plain">]);</code></div>
<div class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php keyword">break</code><code class="php plain">;</code></div>
<div class="line number21 index20 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number22 index21 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number23 index22 alt2"> </div>
<div class="line number24 index23 alt1"><code class="php spaces"> </code><code class="php keyword">return</code> <code class="php plain">true;</code></div>
<div class="line number25 index24 alt2"><code class="php plain">}</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p>有了新增和删除,我们就可以重新写一下task2以及新增task4:</p>
<table class="syntaxhighlighterphp" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
<div class="line number11 index10 alt2">11</div>
<div class="line number12 index11 alt1">12</div>
<div class="line number13 index12 alt2">13</div>
<div class="line number14 index13 alt1">14</div>
<div class="line number15 index14 alt2">15</div>
<div class="line number16 index15 alt1">16</div>
<div class="line number17 index16 alt2">17</div>
<div class="line number18 index17 alt1">18</div>
<div class="line number19 index18 alt2">19</div>
<div class="line number20 index19 alt1">20</div>
<div class="line number21 index20 alt2">21</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="php keyword">function</code> <code class="php plain">task4(){</code></div>
<div class="line number2 index1 alt1"><code class="php spaces"> </code><code class="php variable">$task_id</code> <code class="php plain">= (yield getTaskId());</code></div>
<div class="line number3 index2 alt2"><code class="php spaces"> </code><code class="php keyword">while</code> <code class="php plain">(true) {</code></div>
<div class="line number4 index3 alt1"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"任务{$task_id}发送短信\n"</code><code class="php plain">;</code></div>
<div class="line number5 index4 alt2"><code class="php spaces"> </code><code class="php plain">yield;</code></div>
<div class="line number6 index5 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number7 index6 alt2"><code class="php plain">}</code></div>
<div class="line number8 index7 alt1"><code class="php keyword">function</code> <code class="php plain">task2()</code></div>
<div class="line number9 index8 alt2"><code class="php plain">{</code></div>
<div class="line number10 index9 alt1"><code class="php spaces"> </code><code class="php variable">$task_id</code> <code class="php plain">= (yield getTaskId());</code></div>
<div class="line number11 index10 alt2"><code class="php spaces"> </code><code class="php variable">$child_task_id</code> <code class="php plain">= (yield newTask(task4()));</code></div>
<div class="line number12 index11 alt1"><code class="php spaces"> </code><code class="php keyword">for</code> <code class="php plain">(</code><code class="php variable">$i</code> <code class="php plain">= 0; </code><code class="php variable">$i</code> <code class="php plain"><= 500; </code><code class="php variable">$i</code><code class="php plain">++) {</code></div>
<div class="line number13 index12 alt2"><code class="php spaces"> </code><code class="php comments">//发送邮件给500名会员,大概3000微秒</code></div>
<div class="line number14 index13 alt1"><code class="php spaces"> </code><code class="php plain">usleep(3000);</code></div>
<div class="line number15 index14 alt2"><code class="php spaces"> </code><code class="php functions">echo</code> <code class="php string">"任务{$task_id}发送邮件{$i}\n"</code><code class="php plain">;</code></div>
<div class="line number16 index15 alt1"><code class="php spaces"> </code><code class="php plain">yield </code><code class="php variable">$i</code><code class="php plain">;</code></div>
<div class="line number17 index16 alt2"><code class="php spaces"> </code><code class="php keyword">if</code><code class="php plain">(</code><code class="php variable">$i</code><code class="php plain">==200){</code></div>
<div class="line number18 index17 alt1"><code class="php spaces"> </code><code class="php plain">yield killTask(</code><code class="php variable">$child_task_id</code><code class="php plain">);</code></div>
<div class="line number19 index18 alt2"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number20 index19 alt1"><code class="php spaces"> </code><code class="php plain">}</code></div>
<div class="line number21 index20 alt2"><code class="php plain">}</code></div>
</div>
</td>
</tr>
</tbody>
</table>
<p>运行结果:</p>
<p><img src="http://image.php20.cn/Upload/image/ueditor/20180902/1535877533695565.png"></p>
<p> </p>
<p> </p>
<p>这样我们就完美的实现了新增任务,以及杀死任务了</p>
<p> </p>
<p> </p>
<h1>总结</h1>
<p> </p>
<p>前面所说的,协程只是一种编程逻辑,一种写代码的技巧,协程能够帮助我们更好的切换代码中任务</p>
<p>从上面的例子不难发现,其实协程实现封装较为麻烦,并且不用协程也能实现这些功能,那为什么要用协程呢?</p>
<p>因为协程可以让代码更加的简洁,任务相互之间独立区分开,可以使代码更加的清爽</p>
<p>协程让我们可以更好的控制切换任务流</p>
<p> </p>
<p>前面介绍了那么多,或许有很多人感觉不对,会说"协程不能提升效率吗?","协程到底用来干什么的?"</p>
<p> </p>
<p>或许由上面的例子很难看出协程的用处,那我们继续举例子吧:</p>
<p>js ajax是phper都了解的一个技术,</p>
<p>当点击一个按钮时,先将点击事件ajax传输给后端进行增加一条点击数据,然后出现一个动画,这是一个很正常的事,那么请问,如果ajax是同步,并且在网络不好的情况,会发生什么呢?</p>
<p>没错,点击之后,页面将会卡几秒(网络不好),请求完毕之后,才会出现一个动画.</p>
<p> </p>
<p>协程的用处就在这了,我们可以利用协程,把一些同步io等待的代码逻辑,改为异步,在等待的时间内,可以让cpu去处理其他任务,</p>
<p>就如同小学时候做的一道题:</p>
<p>小明烧开水需要10分钟,刷牙需要3分钟,吃早餐需要5分钟,请问做完这些事情总共需要多少分钟?</p>
<p>答案是10分钟,因为在烧开水这个步骤时,不需要坐在那里看水壶烧(异步,io耗时)可以先去刷牙,然后去吃早餐</p>
<p> </p>
<p>以上就是php yield关于协程的全部内容了</p>
<p> </p>
<p> </p>
<p> </p>
<h1>swoole</h1>
<p> </p>
<p>由总结可以看出,协程用在最多的应用场景,在于需要io耗时,cpu可以节省出来的场景,并且必须要是异步操作</p>
<p>这里推荐swoole扩展https://www.swoole.com/,</p>
<p> </p>
<p>Swoole-4.1.0正式版发布, 主要改动及新特性:</p>
<p>+ PHP原生Redis、PDO、MySQLi轻松协程化, 使用Swoole\Runtime::enableCorotuine()即可将普通的同步阻塞Redis、PDO、MySQLi操作变为协程调度的异步非阻塞IO</p>
<p>+ 协程跟踪功能: 新增两个方法 Coroutine::listCoroutines()可遍历当前所有协程, Coroutine::getBackTrace($cid)可获取某个协程的函数调用栈</p>
<p>+ 支持在协程和Server中使用exit, 此时将会抛出可捕获的\Swoole\ExitException异常</p>
<p>+ 移除所有迭代器(table/connection/coroutine_list)的PCRE依赖限制</p>
<p>+ 新增http_compression配置项, 底层会自动判断客户端传入的Accept-Encoding选择合适的压缩方法, 支持GoogleBrotli压缩</p>
<p>+ 重构了底层Channel和协程Http客户端的C代码为C++协程模式, 解决历史遗留的异步时序问题, 稳定性大大提升</p>
<p>+ 更完整稳定的HTTP2支持和SSL处理</p>
<p>+ 增加open_websocket_close_frame配置, 可以在onMessage事件中接收close帧</p>
<p>具体更新内容文档: https://wiki.swoole.com/wiki/page/966.html</p><br><br>
来源：https://www.cnblogs.com/liliuguang/p/10909944.html
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