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EventDispatcherTrait.php
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EventDispatcherTrait.php
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<?php
/**
* Webino™ (http://webino.sk)
*
* @link https://github.com/webino/event-emitter
* @copyright Copyright (c) 2019 Webino, s.r.o. (http://webino.sk)
* @author Peter Bačinský <peter@bacinsky.sk>
* @license BSD-3-Clause
*/
namespace Webino;
/**
* Trait EventDispatcherTrait
* @package event-emitter
* @since 1.1.0
*/
trait EventDispatcherTrait
{
/**
* Subscribed events and their handlers.
*
* STRUCTURE:
* [
* <string name> => [
* <int priority> => [
* 0 => [<callable handler>, ...]
* ],
* ...
* ],
* ...
* ]
*
* NOTE:
* This structure helps us to reuse the list of handlers
* instead of first iterating over it and generating a new one
* -> In result it improves performance by up to 25% even if it looks a bit strange
*
* @var array[]
*/
protected $events = [];
/**
* @var EventInterface|null
*/
protected $eventPrototype;
/**
* Invoke handlers.
*
* @api
* @param string|EventInterface $event Event name or object
* @param callable|null $until Invoke handlers until callback return value evaluate to true
* @param EventEmitterInterface|null $target
* @return EventInterface Event object
*/
public function emit($event, callable $until = null, EventEmitterInterface $target = null): EventInterface
{
$event = $this->normalizeEvent($event);
$name = $event->getName();
if (empty($name)) {
throw (new InvalidEventException('Cannot emit event %s missing a name'))
->format($event);
}
// get handlers by priority in reverse order
$handlers = $this->getHandlers($name);
// set event initial values
$event->setResults([]);
$event->stop(false);
if ($target) {
$event->setTarget($target);
} elseif ($this instanceof EventEmitterInterface) {
$event->setTarget($this);
}
// invoke handlers
foreach ($handlers as $eventHandlers) {
foreach ($eventHandlers as $subHandlers) {
foreach ($subHandlers as $callback) {
$result = $callback($event);
$event->setResult($result);
// stop propagation if the event was asked to
if ($event->isStopped()) {
return $event;
}
// stop propagation if the result causes our validation callback to return true
if ($until && $until($result)) {
return $event;
}
}
}
}
return $event;
}
/**
* Set event handler.
*
* @api
* @param string|EventInterface|EventHandlerInterface $event Event name, object or event handler
* @param callable|null $callback Event handler
* @param int $priority Handler invocation priority
* @return void
*/
public function on($event, $callback = null, int $priority = 0)
{
if ($event instanceof EventHandlerInterface && $this instanceof EventDispatcherInterface) {
$event->attachEventEmitter($this);
return;
}
$event = $this->normalizeEvent($event);
$name = $event->getName();
isset($this->events[$name]) or $this->events[$name] = [];
isset($this->events[$name][(int)$priority]) or $this->events[$name][(int)$priority] = [];
isset($this->events[$name][(int)$priority][0]) or $this->events[$name][(int)$priority][0] = [];
$this->events[$name][(int)$priority][0][] = $callback;
}
/**
* Remove event handler.
*
* @api
* @param callable|EventHandlerInterface|null $callback Event handler
* @param string|EventInterface|null $event Event name or object
* @return void
*/
public function off($callback = null, $event = null): void
{
if ($callback instanceof EventHandlerInterface && $this instanceof EventEmitterInterface) {
$callback->detachEventEmitter($this);
return;
}
if (!$event) {
// remove listeners from all events
foreach (array_keys($this->events) as $name) {
$this->off($callback, $name);
}
return;
}
$event = $this->normalizeEvent($event);
$name = $event->getName();
if (!isset($this->events[$name])) {
return;
}
foreach ($this->events[$name] as $priority => $handlers) {
foreach ($handlers[0] as $index => $subHandler) {
if ($callback && $subHandler !== $callback) {
continue;
}
// remove founded listener
unset($this->events[$name][$priority][0][$index]);
// remove event if the queue for given priority is empty
if (empty($this->events[$name][$priority][0])) {
unset($this->events[$name][$priority]);
break;
}
}
}
// remove event if the queue given is empty
if (empty($this->events[$name])) {
unset($this->events[$name]);
}
}
/**
* Return listeners sort by priority in reverse order.
*
* @param string|null $name Event name
* @return array Sorted listeners
*/
protected function getHandlers(string $name = null): array
{
if (isset($this->events[$name])) {
$handlers = $this->events[$name];
if (isset($this->events['*'])) {
foreach ($this->events['*'] as $priority => $handlers) {
$handlers[$priority][] = $handlers[0];
}
}
} elseif (isset($this->events['*'])) {
$handlers = $this->events['*'];
} else {
$handlers = [];
}
krsort($handlers);
return $handlers;
}
/**
* Return event as object, if any.
*
* @param string|EventInterface|object $event Event name or object
* @return EventInterface Event object
* @throws InvalidArgumentException Invalid event
*/
protected function normalizeEvent($event): EventInterface
{
if (is_string($event)) {
$eventClone = clone $this->getEventPrototype();
$eventClone->setName($event);
return $eventClone;
}
if ($event instanceof EventInterface) {
return $event;
}
throw (new InvalidArgumentException('Expected event as: %s instead of: %s;'))
->format('string|EventInterface', $event);
}
/**
* @return EventInterface
*/
protected function getEventPrototype(): EventInterface
{
if (!$this->eventPrototype) {
if ($this instanceof EventEmitterInterface) {
$this->eventPrototype = new Event(null, $this);
} else {
$this->eventPrototype = new Event;
}
}
return $this->eventPrototype;
}
}