php实现协程，真正的异步

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php实现协程，真正的异步

2016-06-15 18:43 1454人阅读评论(1)收藏举报

分类：

php（5）

github上php的协程大部分是根据这篇文章实现的：http://nikic.github.io/2012/12/22/Cooperative-multitasking-using-coroutines-in-PHP.html。

它们最终的结果都是把回调变成了优雅的顺序执行的代码，但还是阻塞的，不是真正的异步。

比如最热门的：https://github.com/recoilphp/recoil

先安装：

[html] view plain copy

composer require recoil/recoil

执行：

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<?php
//recoil.php
include __DIR__ . '/vendor/autoload.php';
use Recoil\React\ReactKernel;
$i = 100000;
ReactKernel::start(task1());
ReactKernel::start(task2());
function task1(){
global $i;
echo "wait start" . PHP_EOL;
while ($i-- > 0) {
yield;
}
echo "wait end" . PHP_EOL;
};
function task2(){
echo "Hello " . PHP_EOL;
yield;
echo "world!" . PHP_EOL;
}

结果：

wait start
//等待若干秒
wait end
Hello
world!

我本来是想让两个任务并行，结果两个任务变成了串行，中间等待的时间什么事情都干不了。React响应式的编程是严格禁止这种等待的，所以我就参照unity3d的协程自己写了个php版本的。上代码：

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<?php
//Coroutine.php
//依赖swoole实现的定时器，也可以用其它方法实现定时器
class Coroutine
{
//可以根据需要更改定时器间隔，单位ms
const TICK_INTERVAL = 1;
private $routineList;
private $tickId = -1;
public function __construct()
{
$this->routineList = [];
}
public function start(Generator $routine)
{
$task = new Task($routine);
$this->routineList[] = $task;
$this->startTick();
}
public function stop(Generator $routine)
{
foreach ($this->routineList as $k => $task) {
if($task->getRoutine() == $routine){
unset($this->routineList[$k]);
}
}
}
private function startTick()
{
swoole_timer_tick(self::TICK_INTERVAL, function($timerId){
$this->tickId = $timerId;
$this->run();
});
}
private function stopTick()
{
if($this->tickId >= 0) {
swoole_timer_clear($this->tickId);
}
}
private function run()
{
if(empty($this->routineList)){
$this->stopTick();
return;
}
foreach ($this->routineList as $k => $task) {
$task->run();
if($task->isFinished()){
unset($this->routineList[$k]);
}
}
}
}
class Task
{
protected $stack;
protected $routine;
public function __construct(Generator $routine)
{
$this->routine = $routine;
$this->stack = new SplStack();
}
/**
* [run 协程调度]
* @return [type] [description]
*/
public function run()
{
$routine = &$this->routine;
try {
if(!$routine){
return;
}
$value = $routine->current();
//嵌套的协程
if ($value instanceof Generator) {
$this->stack->push($routine);
$routine = $value;
return;
}
//嵌套的协程返回
if(!$routine->valid() && !$this->stack->isEmpty()) {
$routine = $this->stack->pop();
}
$routine->next();
} catch (Exception $e) {
if ($this->stack->isEmpty()) {
/*
throw the exception
*/
return;
}
}
}
/**
* [isFinished 判断该task是否完成]
* @return boolean [description]
*/
public function isFinished()
{
return $this->stack->isEmpty() && !$this->routine->valid();
}
public function getRoutine()
{
return $this->routine;
}
}

测试代码：

[php] view plain copy

<?php
//test.php
require 'Coroutine.php';
$i = 10000;
$c = new Coroutine();
$c->start(task1());
$c->start(task2());
function task1(){
global $i;
echo "wait start" . PHP_EOL;
while ($i-- > 0) {
yield;
}
echo "wait end" . PHP_EOL;
};
function task2(){
echo "Hello " . PHP_EOL;
yield;
echo "world!" . PHP_EOL;
}

结果：

wait start
Hello
world!
//等待几秒，但不阻塞
wait end

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