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amp/lib/CancellationToken.php

50 lines
1.5 KiB
PHP

<?php
namespace Amp;
/**
* Cancellation tokens are simple objects that allow registering handlers to subscribe to cancellation requests.
*/
interface CancellationToken
{
/**
* Subscribes a new handler to be invoked on a cancellation request.
*
* This handler might be invoked immediately in case the token has already been cancelled. Returned generators will
* automatically be run as coroutines. Any unhandled exceptions will be throw into the event loop.
*
* @param callable $callback Callback to be invoked on a cancellation request. Will receive a `CancelledException`
* as first argument that may be used to fail the operation's promise.
*
* @return string Identifier that can be used to cancel the subscription.
*/
public function subscribe(callable $callback): string;
/**
* Unsubscribes a previously registered handler.
*
* The handler will no longer be called as long as this method isn't invoked from a subscribed callback.
*
* @param string $id
*
* @return void
*/
public function unsubscribe(string $id);
/**
* Returns whether cancellation has been requested yet.
*
* @return bool
*/
public function isRequested(): bool;
/**
* Throws the `CancelledException` if cancellation has been requested, otherwise does nothing.
*
* @return void
*
* @throws CancelledException
*/
public function throwIfRequested();
}