关于php:php-实现-Promiseall-和-Promiserace

测试

$promise1 = function () {msleep(500);
  return 'one';
};
$promise2 = function () {msleep(100);
  return 'two';
};
$promise3 = function () {msleep(50);
  throw new \Exception('Reject');
};
var_dump(promise_all([$promise1, $promise2]));
var_dump(promise_race([$promise1, $promise2]));
var_dump(promise_race([$promise1, $promise2, $promise3]));

后果

# php promise.php
array(2) {[1]=>
string(3) "two"
[0]=>
string(3) "one"
}
string(3) "two"
object(Exception)#15 (7) {}

实现

<?php

declare(strict_types=1);

use Swow\Coroutine;
use Swow\Channel;
use Swow\Selector;
use Swow\Sync\WaitGroup;
use function Swow\defer;

/**
 * @param array $callbacks 
 * @param int $parallel 并发数量
 * @return array 
 */
function promise_all(array $callbacks, int $parallel = -1)
{$wg = new WaitGroup();
  $channel = new Channel($parallel);
  $results = [];
  foreach ($callbacks as $key => $callback) {$wg->add();
      $channel->push(true);
      Coroutine::run(static function () use ($wg, $channel, $callback, $key, &$results) {
          try {$results[$key] = $callback();} catch (\Throwable) { } finally {$channel->pop();
              $wg->done();}
      });
  }
  $wg->wait();
  return $results;
}

/**
 * @param array $callbacks 
 * @param int $timeout 超时
 * @param bool $throw 是否抛出异样
 * @return mixed 
 */
function promise_race(array $callbacks, int $timeout = -1, bool $throw = true)
{$coroutines = [];
  defer(static function () use (&$coroutines) {Coroutine::run(static function () use (&$coroutines) {foreach ($coroutines as $coroutine) {if ($coroutine && $coroutine->isAlive()) {$coroutine->kill();
              }
          }
      });
  });
  $selector = new Selector();
  foreach ($callbacks as $callback) {$channel = new Channel();
      $coroutines[] = Coroutine::run(static function () use ($channel, $callback) {
          try {$channel->push($callback());
          } catch (\Throwable $e) {$channel->push($e);
          }
      });
      $selector->pop($channel);
  }
  try {$selector->commit($timeout);
      return $selector->fetch();} catch (\Throwable $e) {if ($throw) {throw $e;}
  }
  return false;
}