<?php namespace Illuminate\Events;
use Exception;
use ReflectionClass;
use Illuminate\Container\Container;
use Illuminate\Contracts\Events\Dispatcher as DispatcherContract;
use Illuminate\Contracts\Container\Container as ContainerContract;
class Dispatcher implements DispatcherContract {
/**
* The IoC container instance.
*
* @var \Illuminate\Contracts\Container\Container
*/
protected $container;
/**
* The registered event listeners.
*
* @var array
*/
protected $listeners = array();
/**
* The wildcard listeners.
*
* @var array
*/
protected $wildcards = array();
/**
* The sorted event listeners.
*
* @var array
*/
protected $sorted = array();
/**
* The event firing stack.
*
* @var array
*/
protected $firing = array();
/**
* The queue resolver instance.
*
* @var callable
*/
protected $queueResolver;
/**
* Create a new event dispatcher instance.
*
* @param \Illuminate\Contracts\Container\Container $container
* @return void
*/
public function __construct(ContainerContract $container = null)
{
$this->container = $container ?: new Container;
}
/**
* Register an event listener with the dispatcher.
*
* @param string|array $events
* @param mixed $listener
* @param int $priority
* @return void
*/
public function listen($events, $listener, $priority = 0)
{
foreach ((array) $events as $event)
{
if (str_contains($event, '*'))
{
$this->setupWildcardListen($event, $listener);
}
else
{
$this->listeners[$event][$priority][] = $this->makeListener($listener);
unset($this->sorted[$event]);
}
}
}
/**
* Setup a wildcard listener callback.
*
* @param string $event
* @param mixed $listener
* @return void
*/
protected function setupWildcardListen($event, $listener)
{
$this->wildcards[$event][] = $this->makeListener($listener);
}
/**
* Determine if a given event has listeners.
*
* @param string $eventName
* @return bool
*/
public function hasListeners($eventName)
{
return isset($this->listeners[$eventName]);
}
/**
* Register an event and payload to be fired later.
*
* @param string $event
* @param array $payload
* @return void
*/
public function push($event, $payload = array())
{
$this->listen($event.'_pushed', function() use ($event, $payload)
{
$this->fire($event, $payload);
});
}
/**
* Register an event subscriber with the dispatcher.
*
* @param object|string $subscriber
* @return void
*/
public function subscribe($subscriber)
{
$subscriber = $this->resolveSubscriber($subscriber);
$subscriber->subscribe($this);
}
/**
* Resolve the subscriber instance.
*
* @param object|string $subscriber
* @return mixed
*/
protected function resolveSubscriber($subscriber)
{
if (is_string($subscriber))
{
return $this->container->make($subscriber);
}
return $subscriber;
}
/**
* Fire an event until the first non-null response is returned.
* 触发一个事件直到首个非空响应被返回。
*
* @param string $event
* @param array $payload
* @return mixed
*/
public function until($event, $payload = array())
{
return $this->fire($event, $payload, true);
}
/**
* Flush a set of pushed events.
*
* @param string $event
* @return void
*/
public function flush($event)
{
$this->fire($event.'_pushed');
}
/**
* Get the event that is currently firing.
*
* @return string
*/
public function firing()
{
return last($this->firing);
}
/**
* Fire an event and call the listeners.
* 触发一个事件，并调用其事件监听。
*
* @param string|object $event
* @param mixed $payload
* @param bool $halt
* @return array|null
*/
public function fire($event, $payload = array(), $halt = false)
{
// When the given "event" is actually an object we will assume it is an event
// object and use the class as the event name and this event itself as the
// payload to the handler, which makes object based events quite simple.
if (is_object($event))
{
list($payload, $event) = [[$event], get_class($event)];
}
$responses = array();
// If an array is not given to us as the payload, we will turn it into one so
// we can easily use call_user_func_array on the listeners, passing in the
// payload to each of them so that they receive each of these arguments.
if ( ! is_array($payload)) $payload = array($payload);
$this->firing[] = $event;
foreach ($this->getListeners($event) as $listener)
{
$response = call_user_func_array($listener, $payload);
// If a response is returned from the listener and event halting is enabled
// we will just return this response, and not call the rest of the event
// listeners. Otherwise we will add the response on the response list.
if ( ! is_null($response) && $halt)
{
array_pop($this->firing);
return $response;
}
// If a boolean false is returned from a listener, we will stop propagating
// the event to any further listeners down in the chain, else we keep on
// looping through the listeners and firing every one in our sequence.
if ($response === false) break;
$responses[] = $response;
}
array_pop($this->firing);
return $halt ? null : $responses;
}
/**
* Get all of the listeners for a given event name.
*
* @param string $eventName
* @return array
*/
public function getListeners($eventName)
{
$wildcards = $this->getWildcardListeners($eventName);
if ( ! isset($this->sorted[$eventName]))
{
$this->sortListeners($eventName);
}
return array_merge($this->sorted[$eventName], $wildcards);
}
/**
* Get the wildcard listeners for the event.
*
* @param string $eventName
* @return array
*/
protected function getWildcardListeners($eventName)
{
$wildcards = array();
foreach ($this->wildcards as $key => $listeners)
{
if (str_is($key, $eventName)) $wildcards = array_merge($wildcards, $listeners);
}
return $wildcards;
}
/**
* Sort the listeners for a given event by priority.
*
* @param string $eventName
* @return array
*/
protected function sortListeners($eventName)
{
$this->sorted[$eventName] = array();
// If listeners exist for the given event, we will sort them by the priority
// so that we can call them in the correct order. We will cache off these
// sorted event listeners so we do not have to re-sort on every events.
if (isset($this->listeners[$eventName]))
{
krsort($this->listeners[$eventName]);
$this->sorted[$eventName] = call_user_func_array(
'array_merge', $this->listeners[$eventName]
);
}
}
/**
* Register an event listener with the dispatcher.
*
* @param mixed $listener
* @return mixed
*/
public function makeListener($listener)
{
return is_string($listener) ? $this->createClassListener($listener) : $listener;
}
/**
* Create a class based listener using the IoC container.
*
* @param mixed $listener
* @return \Closure
*/
public function createClassListener($listener)
{
$container = $this->container;
return function() use ($listener, $container)
{
return call_user_func_array(
$this->createClassCallable($listener, $container), func_get_args()
);
};
}
/**
* Create the class based event callable.
*
* @param string $listener
* @param \Illuminate\Container\Container $container
* @return callable
*/
protected function createClassCallable($listener, $container)
{
list($class, $method) = $this->parseClassCallable($listener);
if ($this->handlerShouldBeQueued($class))
{
return $this->createQueuedHandlerCallable($class, $method);
}
else
{
return array($container->make($class), $method);
}
}
/**
* Parse the class listener into class and method.
*
* @param string $listener
* @return array
*/
protected function parseClassCallable($listener)
{
$segments = explode('@', $listener);
return [$segments[0], count($segments) == 2 ? $segments[1] : 'handle'];
}
/**
* Determine if the event handler class should be queued.
*
* @param string $class
* @return bool
*/
protected function handlerShouldBeQueued($class)
{
try
{
return (new ReflectionClass($class))->implementsInterface(
'Illuminate\Contracts\Queue\ShouldBeQueued'
);
}
catch (Exception $e)
{
return false;
}
}
/**
* Create a callable for putting an event handler on the queue.
*
* @param string $class
* @param string $method
* @return \Closure
*/
protected function createQueuedHandlerCallable($class, $method)
{
return function() use ($class, $method)
{
$arguments = $this->cloneArgumentsForQueueing(func_get_args());
if (method_exists($class, 'queue'))
{
$this->callQueueMethodOnHandler($class, $method, $arguments);
}
else
{
$this->resolveQueue()->push('Illuminate\Events\CallQueuedHandler@call', [
'class' => $class, 'method' => $method, 'data' => serialize($arguments),
]);
}
};
}
/**
* Clone the given arguments for queueing.
*
* @param array $arguments
* @return array
*/
protected function cloneArgumentsForQueueing(array $arguments)
{
return array_map(function($a) { return is_object($a) ? clone $a : $a; }, $arguments);
}
/**
* Call the queue method on the handler class.
*
* @param string $class
* @param string $method
* @param array $arguments
* @return void
*/
protected function callQueueMethodOnHandler($class, $method, $arguments)
{
$handler = (new ReflectionClass($class))->newInstanceWithoutConstructor();
$handler->queue($this->resolveQueue(), 'Illuminate\Events\CallQueuedHandler@call', [
'class' => $class, 'method' => $method, 'data' => serialize($arguments),
]);
}
/**
* Remove a set of listeners from the dispatcher.
*
* @param string $event
* @return void
*/
public function forget($event)
{
unset($this->listeners[$event], $this->sorted[$event]);
}
/**
* Forget all of the pushed listeners.
*
* @return void
*/
public function forgetPushed()
{
foreach ($this->listeners as $key => $value)
{
if (ends_with($key, '_pushed')) $this->forget($key);
}
}
/**
* Get the queue implementation from the resolver.
*
* @return \Illuminate\Contracts\Queue\Queue
*/
protected function resolveQueue()
{
return call_user_func($this->queueResolver);
}
/**
* Set the queue resolver implementation.
* 设置队列解析器的实现。
*
* @param callable $resolver
* @return $this
*/
public function setQueueResolver(callable $resolver)
{
$this->queueResolver = $resolver;
return $this;
}
}