The parallel\Events class

(0.9.0)

The Event Loop

The Event loop monitors the state of sets of futures and or channels (targets) in order to perform read (parallel\Future::value(), parallel\Channel::recv()) and write (parallel\Channel::send()) operations as the targets become available and the operations may be performed without blocking the event loop.

类摘要

final parallel\Events implements Countable , Traversable {
/* Input */
public setInput ( Input $input ) : void
/* Targets */
public addChannel ( parallel\Channel $channel ) : void
public addFuture ( string $name , parallel\Future $future ) : void
public remove ( string $target ) : void
/* Behaviour */
public setBlocking ( bool $blocking ) : void
public setTimeout ( int $timeout ) : void
/* Polling */
public poll ( ) : parallel\Events\Event|null
}

Table of Contents

User Contributed Notes

gam6itko 25-Sep-2021 07:24
<?php

// example below shows how to stop child thread from main thread

use parallel\{Channel, Events, Events\Event\Type, Runtime};

$fnThread = static function (Channel $channel) {
    $events = new Events();
    $events->addChannel($channel);
    $events->setBlocking(false); // don't block on Events::poll()

    while (true) {
        if ($event = $events->poll()) {
            //It seems, the target gets deleted after returning an event, so add it again.
            $events->addChannel($channel);

            if (Type::Read === $event->type) {
                echo "- received value: ".$event->value.PHP_EOL;
            } elseif (Type::Close === $event->type) {
                echo "- receiving close event".PHP_EOL;
                return "i'm done";
            }

        }
        echo "-\n";
        usleep(500_000);
    }
};

// main thread
$runtime = new Runtime();
$channel = new Channel();
$future = $runtime->run($fnThread, [$channel]);

$channel->send('message1');
sleep(2);
$channel->send('message2');
sleep(2);

echo "closing channel\n";
$channel->close();
echo "future said: ".$future->value();
echo PHP_EOL;
gam6itko 11-Sep-2021 03:28
<?php

// this example shows how Events handle Future events

use parallel\{Events, Events\Event, Runtime};

$events = new Events();

$runtime = new Runtime();

//Read (type: 1)
$future = $runtime->run(
    static function (string $name) {
        return "Future#$name result";
    },
    ['Read']
);
$events->addFuture("Future#Read", $future);

//Cancel  (type: 4)
$future = $runtime->run(
    static function (string $name) {
        throw new \Exception("Exception#$name");
    },
    ['Cancel']
);
$events->addFuture("Future#Cancel", $future);

//Kill  (type: 5)
$future = $runtime->run(
    static function () {
        sleep(100000);
    },
    []
);
$events->addFuture("Future#Kill", $future);
$future->cancel(); //kill it

//Error  (type: 6)
$future = $runtime->run(
    static function () {
        $memoryEater = [];
        $i = 0;
        while (++$i) {
            $memoryEater[] = $i;
        }
    }
);
$events->addFuture("Future#Error", $future);

// reading events

/** @var Event $event */
foreach ($events as $i => $event) {
    echo str_pad('', 50, '=') . " EVENT_$i\n";
    var_dump($event);
    echo "\n";
}
s dot laufer at homegear dot email 22-Dec-2019 03:02
<?php
/**
Example showing the usage of events.

The documentation still is very thin, so I'm not sure, the example is the best solution. But it works.
*/
use parallel\{Channel,Runtime,Events,Events\Event};

$myThread = function(Channel $channel) {
    $events = new Events();
    $events->addChannel($channel);
    //$events->setBlocking(false); //Uncomment to don't block on Events::poll()
    $events->setTimeout(1000000); //Comment when not blocking

    while(true)
    {
        /*
        ...
        Your code.
        ...
        */

        //Read all available events
        try
        {
            $event = NULL;
            do
            {
                $event = $events->poll(); //Returns non-null if there is an event
                if($event && $event->source == 'myChannel')
                {
                    //It seems, the target gets deleted after returning an event,
                    //so add it again.
                    $events->addChannel($channel);
                    if($event->type == Event\Type::Read)
                    {
                        if(is_array($event->value) && count($event->value) > 0)
                        {
                            if($event->value['name'] == 'stop')
                            {
                                echo 'Stopping thread';
                                return; //Stop
                            }
                            else
                            {
                                echo 'Event: '.$event->value['name'].' => '.$event->value['value'].PHP_EOL;
                            }
                        }
                    }
                    else if($event->type == Event\Type::Close) return; //Stop
                }
            }
            while($event);
        }
        catch(Events\Error\Timeout $ex)
        {
            //Timeout
            echo 'Timeout'.PHP_EOL;
        }
    }
};

class MyClass {
    private $runtime;
    private $future;
    private $channel;

    public function start() {
        //Create runtime
        $this->runtime = new Runtime();

        //Create buffered channel.
        //Buffered channels don't block on Channel::send().
        //Note that target names need to be unique within the process.
        $this->channel = Channel::make('myChannel', Channel::Infinite);

        global $myThread;
        $this->future = $this->runtime->run($myThread, [$this->channel]);
    }

    public function stop() {
        $this->channel->send(['name' => 'stop', 'value' => true]);

        $this->future->value(); //Wait for thread to finish
        $this->channel->close();
    }

    public function emit(string $name, $value)
    {
        $this->channel->send(['name' => $name, 'value' => $value]);
    }
}

$a = new MyClass();
$a->start();

for($i = 0; $i < 5; $i++)
{
    $a->emit('test', $i);
    sleep(0.5);
}

sleep(2);

for($i = 5; $i < 10; $i++)
{
    $a->emit('test', $i);
    sleep(0.5);
}

$a->stop();
?>
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