Support promise cancellation

[clue]

• Add cancellation support for resolve() and reject()
  • Remove internal timers
  • Reject resulting promise with RuntimeException
• Add cancellation support for timeout()
  • Only cancel input promise (see Support promise cancellation #13 for some background, thanks @jsor)
• Cancellation of input promise for timeout() is not affected

Closes#3, supersedes/closes#13

[jsor]

👍

---

For the record (not suitable right now because it'd be a BC), i recommend to not typehint against PromiseInterface but use Promise\resolve to turn any input into a Promiseinstance.

namespaceReact\Promise\Timer;
useReact\EventLoop\LoopInterface;
useReact\Promise;
functiontimeout($input, $time, LoopInterface$loop)
{
$promise = Promise\resolve($input);
returnnewPromise\Promise(function ($resolve, $reject) use ($loop, $time, $promise) {
$timer = $loop->addTimer($time, function () use ($time, $promise, $reject) {
$reject(newTimeoutException($time, 'Timed out after ' . $time . ' seconds'));
$promise->cancel();
});
$promise->then(function ($v) use ($timer, $loop, $resolve) {
$loop->cancelTimer($timer);
$resolve($v);
}, function ($v) use ($timer, $loop, $reject) {
$loop->cancelTimer($timer);
$reject($v);
});
}, array($promise, 'cancel'));
}

The advantages are, that you can remove a few if's and more important, it will be more interoperable once Promise\resolve supports turning foreign promises into React promises.

[jsor]

My, bad. I see now that you're doing the $promise instanceof CancellablePromiseInterface checks because React\Promise ~1.1 is supported.

[clue]

i recommend to not typehint against PromiseInterface but use Promise\resolve to turn any input into a Promiseinstance

Thanks for the suggestion @jsor. I think it makes sense to consider this, despite this being unrelated to this ticket, so I've just filed #19 to keep track of this.

[clue]

I'd like to get in reactphp/promise#48 first so that we can rely on cancellation support to be present in all installations and hence make this feature more predictable. An update to this PR is ready, I'll push this once the other PR is in and a v1.2.0 has been tagged.

[clue]

I'd like to get in reactphp/promise#48 first so that we can rely on cancellation support to be present

The linked PR is now in and I've updated this PR to make this feature more consistently available.

Ready for review

[WyriHaximus]

LGTM

[jsor]