Extend Laravel Events Dispatcher

[mjauvin]

Reuses 90% of Laravel's Events Dispatcher.

[mjauvin]

Check what it actually looks like once merged:

<?php namespace Winter\Storm\Events;

use Exception;
use ReflectionClass;
use Illuminate\Support\Arr;
use Illuminate\Support\Str;
use Illuminate\Container\Container;
use Illuminate\Contracts\Broadcasting\ShouldBroadcast;
use Illuminate\Contracts\Broadcasting\ShouldBroadcastNow; 
use Illuminate\Contracts\Events\Dispatcher as DispatcherContract;
use Illuminate\Contracts\Broadcasting\Factory as BroadcastFactory;
use Illuminate\Contracts\Container\Container as ContainerContract;

class Dispatcher extends \Illuminate\Events\Dispatcher
{
    /**
     * The sorted event listeners.
     *
     * @var array
     */
    protected $sorted = [];

    /**
     * The event firing stack.
     *
     * @var array
     */
    protected $firing = [];

    /** 
     * 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]);
            }
        }
    }

    /** 
     * Get the event that is currently firing.
     *
     * @return string
     */
    public function firing()
    {   
        return last($this->firing);
    }

    /**
     * Fire an event until the first non-null response is returned.
     *
     * @param  string|object  $event
     * @param  mixed  $payload
     * @return array|null
     */
    public function until($event, $payload = [])
    {   
        return $this->dispatch($event, $payload, true);
    } 

    /**
     * Fire an event and call the listeners.
     *
     * @param  string|object  $event
     * @param  mixed  $payload
     * @param  bool  $halt
     * @return array|null
     */
    public function fire($event, $payload = [], $halt = false)
    {   
        return $this->dispatch($event, $payload, $halt);
    }
    
    /**
     * Fire an event and call the listeners.
     *
     * @param  string|object  $event
     * @param  mixed  $payload
     * @param  bool  $halt
     * @return array|null
     */
    public function dispatch($event, $payload = [], $halt = false)
    {   
        // When the given "event" is actually an object we will assume it is an event
        // object and use the class as the event name and this event itself as the
        // payload to the handler, which makes object based events quite simple.
        list($event, $payload) = $this->parseEventAndPayload($event, $payload);
    
        $responses = [];

        // 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)) {
            $payload = [$payload];
        }
    
        $this->firing[] = $event;

        if (isset($payload[0]) && $payload[0] instanceof ShouldBroadcast) {
            $this->broadcastEvent($payload[0]);
        }

        foreach ($this->getListeners($event) as $listener) {
            $response = $listener($event, $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)
    {
        if (!isset($this->sorted[$eventName])) {
            $this->sortListeners($eventName);
        }   

        $listeners = $this->sorted[$eventName] ?? [];

        $listeners = array_merge(
            $listeners,
            $this->wildcardsCache[$eventName] ?? $this->getWildcardListeners($eventName)
        );

        return class_exists($eventName, false)
                    ? $this->addInterfaceListeners($eventName, $listeners)
                    : $listeners;
    }

    /**
     * Sort the listeners for a given event by priority.
     *
     * @param  string  $eventName
     * @return array
     */
    protected function sortListeners($eventName)
    {
        $this->sorted[$eventName] = [];
        
        // 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]
            );
        }
    }

    /**
     * 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('Winter\Storm\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(), 'Winter\Storm\Events\CallQueuedHandler@call', [
            'class' => $class, 'method' => $method, 'data' => serialize($arguments),
        ]); 
    }
}