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feat: Creates PrioritizedIdentifierListenerProvider
The PrioritizedIdentifierListenerProvider mimics functionality present in the SharedEventManager (and implements the SharedEventManagerInterface). Its purpose is to be a drop-in replacement for the `SharedEventManager` to allow users to start migrating to PSR-14 functionality. In the process of working on this implementation, I discovered some complexity in the data structure returned from `getListenersForEventByPriority` implementation of `PrioritizedListenerProvider` that, when mimiced in `PrioritizedIdentifierListenerProvider`, made verifying behavior difficult. In particular, it was this line: ```php $prioritizedListeners[$priority][] = $listOfListeners[0]; ``` The problem that arose is that the `$prioritizedListeners` returned were now two levels deep, which made comparisons far harder. I changed this to read: ``` $prioritizedListeners[$priority] = isset($prioritizedListeners[$priority]) ? array_merge($prioritizedListeners[$priority], $listOfListeners[0]) : $listOfListeners[0]; ``` This makes the return value far simpler, and _should_ keep speed reasonable, though I have yet to benchmark it.
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‎TODO-PSR-14.md

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Original file line numberDiff line numberDiff line change
@@ -34,12 +34,12 @@
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array of identifiers. This method will return all listeners in prioritized
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order.
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- [x] implement `getListenersForEventByPriority`
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- [ ] Create a `PrioritizedIdentifierListenerProvider` that implements
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- [x] Create a `PrioritizedIdentifierListenerProvider` that implements
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both the `PrioritizedListenerProvider` interface and the
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`SharedEventManagerInterface`
40-
- [ ] implement `getListenersForEventByPriority`
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- [ ] `SharedEventManager` will extend this class
42-
- [ ] mark as deprecated (will not use this in v4)
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- [x] implement `getListenersForEventByPriority`
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- [x] `SharedEventManager` will extend this class
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- [x] mark as deprecated (will not use this in v4)
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- [ ] Create a `PrioritizedAggregateListenerProvider` implementation
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- [ ] Accepts a list of `PrioritizedListenerProvider` instances
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- [ ] `getListenersByEvent()` will loop through each, in order, calling the

‎src/ListenerProvider/PrioritizedIdentifierListenerProvider.php

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@@ -0,0 +1,278 @@
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<?php
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/**
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* @see https://github.com/zendframework/zend-eventmanager for the canonical source repository
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* @copyright Copyright (c) 2019 Zend Technologies USA Inc. (https://www.zend.com)
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* @license https://github.com/zendframework/zend-eventmanager/blob/master/LICENSE.md New BSD License
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*/
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namespace Zend\EventManager\ListenerProvider;
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use Zend\EventManager\Exception;
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use Zend\EventManager\SharedEventManagerInterface;
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/**
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* @deprecated This implementation exists to allow the SharedEventManager
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* system to coexist with listener providers during the 3.X series of
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* releases, and will be removed in version 4. Use class and interface
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* names of events when attaching them to a provider instead, as those
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* are most equivalent to the identifier system.
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*/
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class PrioritizedIdentifierListenerProvider implements
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PrioritizedListenerProviderInterface,
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SharedEventManagerInterface
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{
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/**
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* Identifiers with event connections
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*
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* @var array<string, array<string, array<int, callable[]>>>
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*/
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protected $identifiers = [];
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/**
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* {@inheritDoc}
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* @param array $identifiers Identifiers from which to match event listeners.
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* @throws Exception\InvalidArgumentException for invalid event types
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* @throws Exception\InvalidArgumentException for invalid identifier types
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*/
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public function getListenersForEvent($event, array $identifiers = [])
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{
39+
yield from $this->iterateByPriority(
40+
$this->getListenersForEventByPriority($event, $identifiers)
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);
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}
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/**
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* {@inheritDoc}
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* @throws Exception\InvalidArgumentException for invalid event types
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* @throws Exception\InvalidArgumentException for invalid identifier types
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*/
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public function getListenersForEventByPriority($event, array $identifiers = [])
50+
{
51+
$this->validateEventForListenerRetrieval($event, __METHOD__);
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$prioritizedListeners = [];
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$identifiers = $this->normalizeIdentifierList($identifiers);
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$eventList = $this->getEventList($event);
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foreach ($identifiers as $identifier) {
58+
if (! is_string($identifier) || empty($identifier)) {
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throw new Exception\InvalidArgumentException(sprintf(
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'Identifier names passed to %s must be non-empty',
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__METHOD__
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));
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}
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if (! isset($this->identifiers[$identifier])) {
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continue;
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}
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$listenersByIdentifier = $this->identifiers[$identifier];
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foreach ($eventList as $eventName) {
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if (! isset($listenersByIdentifier[$eventName])) {
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continue;
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}
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foreach ($listenersByIdentifier[$eventName] as $priority => $listOfListeners) {
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$prioritizedListeners[$priority] = isset($prioritizedListeners[$priority])
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? array_merge($prioritizedListeners[$priority], $listOfListeners[0])
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: $listOfListeners[0];
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}
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}
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}
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return $prioritizedListeners;
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}
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/**
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* {@inheritDoc}
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* @throws Exception\InvalidArgumentException for invalid identifier types
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* @throws Exception\InvalidArgumentException for invalid event types
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*/
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public function attach($identifier, $eventName, callable $listener, $priority = 1)
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{
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if (! is_string($identifier) || empty($identifier)) {
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throw new Exception\InvalidArgumentException(sprintf(
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'Invalid identifier provided; must be a string; received "%s"',
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gettype($identifier)
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));
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}
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if (! is_string($eventName) || empty($eventName)) {
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throw new Exception\InvalidArgumentException(sprintf(
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'Invalid event provided; must be a non-empty string; received "%s"',
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gettype($eventName)
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));
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}
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$this->identifiers[$identifier][$eventName][(int) $priority][0][] = $listener;
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}
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/**
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* {@inheritDoc}
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* @param bool $force Internal; allows recursing when detaching wildcard listeners
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* @throws Exception\InvalidArgumentException for invalid identifier types
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* @throws Exception\InvalidArgumentException for invalid event name types
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*/
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public function detach(callable $listener, $identifier = null, $eventName = null, $force = false)
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{
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// No identifier or wildcard identifier: loop through all identifiers and detach
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if (null === $identifier || ('*' === $identifier && ! $force)) {
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foreach (array_keys($this->identifiers) as $identifier) {
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$this->detach($listener, $identifier, $eventName, true);
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}
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return;
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}
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if (! is_string($identifier) || empty($identifier)) {
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throw new Exception\InvalidArgumentException(sprintf(
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'Invalid identifier provided; must be a string, received %s',
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gettype($identifier)
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));
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}
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// Do we have any listeners on the provided identifier?
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if (! isset($this->identifiers[$identifier])) {
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return;
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}
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if (null === $eventName || ('*' === $eventName && ! $force)) {
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foreach (array_keys($this->identifiers[$identifier]) as $eventName) {
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$this->detach($listener, $identifier, $eventName, true);
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}
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return;
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}
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if (! is_string($eventName) || empty($eventName)) {
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throw new Exception\InvalidArgumentException(sprintf(
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'Invalid event name provided; must be a string, received %s',
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gettype($eventName)
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));
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}
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if (! isset($this->identifiers[$identifier][$eventName])) {
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return;
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}
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foreach ($this->identifiers[$identifier][$eventName] as $priority => $listOfListeners) {
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foreach ($listOfListeners[0] as $index => $evaluatedListener) {
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if ($evaluatedListener !== $listener) {
160+
continue;
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}
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// Found the listener; remove it.
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unset($this->identifiers[$identifier][$eventName][$priority][0][$index]);
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// Is the priority queue empty?
167+
if (empty($this->identifiers[$identifier][$eventName][$priority][0])) {
168+
unset($this->identifiers[$identifier][$eventName][$priority]);
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break;
170+
}
171+
}
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173+
// Is the event queue empty?
174+
if (empty($this->identifiers[$identifier][$eventName])) {
175+
unset($this->identifiers[$identifier][$eventName]);
176+
break;
177+
}
178+
}
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180+
// Is the identifier queue now empty? Remove it.
181+
if (empty($this->identifiers[$identifier])) {
182+
unset($this->identifiers[$identifier]);
183+
}
184+
}
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/**
187+
* {@inheritDoc}
188+
*/
189+
public function getListeners(array $identifiers, $eventName)
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{
191+
return $this->getListenersForEventByPriority($eventName, $identifiers);
192+
}
193+
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/**
195+
* {@inheritDoc}
196+
*/
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public function clearListeners($identifier, $eventName = null)
198+
{
199+
if (! isset($this->identifiers[$identifier])) {
200+
return false;
201+
}
202+
203+
if (null === $eventName) {
204+
unset($this->identifiers[$identifier]);
205+
return;
206+
}
207+
208+
if (! isset($this->identifiers[$identifier][$eventName])) {
209+
return;
210+
}
211+
212+
unset($this->identifiers[$identifier][$eventName]);
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}
214+
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/**
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* @param mixed $event Event to validate
217+
* @param string $method Method name invoking this one
218+
* @return void
219+
* @throws Exception\InvalidArgumentException for invalid event types
220+
*/
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private function validateEventForListenerRetrieval($event, $method)
222+
{
223+
if (is_object($event)) {
224+
return;
225+
}
226+
227+
if (is_string($event) && '*' !== $event && ! empty($event)) {
228+
return;
229+
}
230+
231+
throw new Exception\InvalidArgumentException(sprintf(
232+
'Event name passed to %s must be a non-empty, non-wildcard string or an object',
233+
$method
234+
));
235+
}
236+
237+
/**
238+
* Deduplicate identifiers, and ensure wildcard identifier is last.
239+
*
240+
* @return string[]
241+
*/
242+
private function normalizeIdentifierList(array $identifiers)
243+
{
244+
$identifiers = array_unique($identifiers);
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if (false !== ($index = array_search('*', $identifiers, true))) {
246+
unset($identifiers[$index]);
247+
}
248+
array_push($identifiers, '*');
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return $identifiers;
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}
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/**
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* @param string|object $event
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* @return string[]
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*/
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private function getEventList($event)
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{
258+
if (is_string($event)) {
259+
return [$event, '*'];
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}
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262+
return is_callable([$event, 'getName'])
263+
? [$event->getName(), get_class($event), '*']
264+
: [get_class($event), '*'];
265+
}
266+
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/**
268+
* @param array $prioritizedListeners
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* @return iterable
270+
*/
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private function iterateByPriority($prioritizedListeners)
272+
{
273+
krsort($prioritizedListeners);
274+
foreach ($prioritizedListeners as $listeners) {
275+
yield from $listeners;
276+
}
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}
278+
}

‎src/ListenerProvider/PrioritizedListenerProvider.php

Lines changed: 5 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -73,7 +73,9 @@ public function getListenersForEventByPriority($event, array $identifiers = [])
7373
}
7474

7575
foreach ($this->events[$name] as $priority => $listOfListeners) {
76-
$prioritizedListeners[$priority][] = $listOfListeners[0];
76+
$prioritizedListeners[$priority] = isset($prioritizedListeners[$priority])
77+
? array_merge($prioritizedListeners[$priority], $listOfListeners[0])
78+
: $listOfListeners[0];
7779
}
7880
}
7981

@@ -189,19 +191,8 @@ public function clearListeners($event)
189191
private function iterateByPriority($prioritizedListeners)
190192
{
191193
krsort($prioritizedListeners);
192-
foreach ($prioritizedListeners as $listenerSets) {
193-
yield from $this->iterateListenerSets($listenerSets);
194-
}
195-
}
196-
197-
/**
198-
* @param iterable $listenerSets
199-
* @return iterable
200-
*/
201-
private function iterateListenerSets($listenerSets)
202-
{
203-
foreach ($listenerSets as $listOfListeners) {
204-
yield from $listOfListeners;
194+
foreach ($prioritizedListeners as $listeners) {
195+
yield from $listeners;
205196
}
206197
}
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}

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