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psalm/src/Psalm/Internal/LanguageServer/EmitterInterface.php
2021-12-15 04:42:37 +01:00

72 lines
2.2 KiB
PHP

<?php
declare(strict_types=1);
namespace Psalm\Internal\LanguageServer;
/**
* Event Emitter Interface
*
* Anything that accepts listeners and emits events should implement this
* interface.
*
* @copyright Copyright (C) fruux GmbH (https://fruux.com/)
* @author Evert Pot (http://evertpot.com/)
* @license http://sabre.io/license/ Modified BSD License
*/
interface EmitterInterface
{
/**
* Subscribe to an event.
*/
public function on(string $eventName, callable $callBack, int $priority = 100): void;
/**
* Emits an event.
*
* This method will return true if 0 or more listeners were successfully
* handled. false is returned if one of the events broke the event chain.
*
* If the continueCallBack is specified, this callback will be called every
* time before the next event handler is called.
*
* If the continueCallback returns false, event propagation stops. This
* allows you to use the eventEmitter as a means for listeners to implement
* functionality in your application, and break the event loop as soon as
* some condition is fulfilled.
*
* Note that returning false from an event subscriber breaks propagation
* and returns false, but if the continue-callback stops propagation, this
* is still considered a 'successful' operation and returns true.
*
* Lastly, if there are 5 event handlers for an event. The continueCallback
* will be called at most 4 times.
*
* @param list<mixed> $arguments
*/
public function emit(
string $eventName,
array $arguments = [],
?callable $continueCallBack = null
): void;
/**
* Returns the list of listeners for an event.
*
* The list is returned as an array, and the list of events are sorted by
* their priority.
*
* @return callable[]
*/
public function listeners(string $eventName): array;
/**
* Removes a specific listener from an event.
*
* If the listener could not be found, this method will return false. If it
* was removed it will return true.
* @psalm-suppress PossiblyUnusedReturnValue
*/
public function removeListener(string $eventName, callable $listener): bool;
}