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amp/lib/Promise.php
2018-06-18 20:00:01 +02:00

31 lines
1.1 KiB
PHP

<?php
namespace Amp;
/**
* Representation of the future value of an asynchronous operation.
*/
interface Promise
{
/**
* Registers a callback to be invoked when the promise is resolved.
*
* If this method is called multiple times, additional handlers will be registered instead of replacing any already
* existing handlers.
*
* If the promise is already resolved, the callback MUST be executed immediately.
*
* Exceptions MUST NOT be thrown from this method. Any exceptions thrown from invoked callbacks MUST be
* forwarded to the event-loop error handler.
*
* Note: You shouldn't implement this interface yourself. Instead, provide a method that returns a promise for the
* operation you're implementing. Objects other than pure placeholders implementing it are a very bad idea.
*
* @param callable(\Throwable|null $reason, $value) $onResolved `$reason` shall be `null` on
* success, `$value` shall be `null` on failure.
*
* @return void
*/
public function onResolve(callable $onResolved);
}