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Diffstat (limited to 'vendor/react/promise/src/Promise.php')
-rw-r--r-- | vendor/react/promise/src/Promise.php | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/vendor/react/promise/src/Promise.php b/vendor/react/promise/src/Promise.php new file mode 100644 index 0000000..33759e6 --- /dev/null +++ b/vendor/react/promise/src/Promise.php @@ -0,0 +1,256 @@ +<?php + +namespace React\Promise; + +class Promise implements ExtendedPromiseInterface, CancellablePromiseInterface +{ + private $canceller; + private $result; + + private $handlers = []; + private $progressHandlers = []; + + private $requiredCancelRequests = 0; + private $cancelRequests = 0; + + public function __construct(callable $resolver, callable $canceller = null) + { + $this->canceller = $canceller; + + // Explicitly overwrite arguments with null values before invoking + // resolver function. This ensure that these arguments do not show up + // in the stack trace in PHP 7+ only. + $cb = $resolver; + $resolver = $canceller = null; + $this->call($cb); + } + + public function then(callable $onFulfilled = null, callable $onRejected = null, callable $onProgress = null) + { + if (null !== $this->result) { + return $this->result->then($onFulfilled, $onRejected, $onProgress); + } + + if (null === $this->canceller) { + return new static($this->resolver($onFulfilled, $onRejected, $onProgress)); + } + + // This promise has a canceller, so we create a new child promise which + // has a canceller that invokes the parent canceller if all other + // followers are also cancelled. We keep a reference to this promise + // instance for the static canceller function and clear this to avoid + // keeping a cyclic reference between parent and follower. + $parent = $this; + ++$parent->requiredCancelRequests; + + return new static( + $this->resolver($onFulfilled, $onRejected, $onProgress), + static function () use (&$parent) { + if (++$parent->cancelRequests >= $parent->requiredCancelRequests) { + $parent->cancel(); + } + + $parent = null; + } + ); + } + + public function done(callable $onFulfilled = null, callable $onRejected = null, callable $onProgress = null) + { + if (null !== $this->result) { + return $this->result->done($onFulfilled, $onRejected, $onProgress); + } + + $this->handlers[] = static function (ExtendedPromiseInterface $promise) use ($onFulfilled, $onRejected) { + $promise + ->done($onFulfilled, $onRejected); + }; + + if ($onProgress) { + $this->progressHandlers[] = $onProgress; + } + } + + public function otherwise(callable $onRejected) + { + return $this->then(null, static function ($reason) use ($onRejected) { + if (!_checkTypehint($onRejected, $reason)) { + return new RejectedPromise($reason); + } + + return $onRejected($reason); + }); + } + + public function always(callable $onFulfilledOrRejected) + { + return $this->then(static function ($value) use ($onFulfilledOrRejected) { + return resolve($onFulfilledOrRejected())->then(function () use ($value) { + return $value; + }); + }, static function ($reason) use ($onFulfilledOrRejected) { + return resolve($onFulfilledOrRejected())->then(function () use ($reason) { + return new RejectedPromise($reason); + }); + }); + } + + public function progress(callable $onProgress) + { + return $this->then(null, null, $onProgress); + } + + public function cancel() + { + if (null === $this->canceller || null !== $this->result) { + return; + } + + $canceller = $this->canceller; + $this->canceller = null; + + $this->call($canceller); + } + + private function resolver(callable $onFulfilled = null, callable $onRejected = null, callable $onProgress = null) + { + return function ($resolve, $reject, $notify) use ($onFulfilled, $onRejected, $onProgress) { + if ($onProgress) { + $progressHandler = static function ($update) use ($notify, $onProgress) { + try { + $notify($onProgress($update)); + } catch (\Throwable $e) { + $notify($e); + } catch (\Exception $e) { + $notify($e); + } + }; + } else { + $progressHandler = $notify; + } + + $this->handlers[] = static function (ExtendedPromiseInterface $promise) use ($onFulfilled, $onRejected, $resolve, $reject, $progressHandler) { + $promise + ->then($onFulfilled, $onRejected) + ->done($resolve, $reject, $progressHandler); + }; + + $this->progressHandlers[] = $progressHandler; + }; + } + + private function reject($reason = null) + { + if (null !== $this->result) { + return; + } + + $this->settle(reject($reason)); + } + + private function settle(ExtendedPromiseInterface $promise) + { + $promise = $this->unwrap($promise); + + if ($promise === $this) { + $promise = new RejectedPromise( + new \LogicException('Cannot resolve a promise with itself.') + ); + } + + $handlers = $this->handlers; + + $this->progressHandlers = $this->handlers = []; + $this->result = $promise; + $this->canceller = null; + + foreach ($handlers as $handler) { + $handler($promise); + } + } + + private function unwrap($promise) + { + $promise = $this->extract($promise); + + while ($promise instanceof self && null !== $promise->result) { + $promise = $this->extract($promise->result); + } + + return $promise; + } + + private function extract($promise) + { + if ($promise instanceof LazyPromise) { + $promise = $promise->promise(); + } + + return $promise; + } + + private function call(callable $cb) + { + // Explicitly overwrite argument with null value. This ensure that this + // argument does not show up in the stack trace in PHP 7+ only. + $callback = $cb; + $cb = null; + + // Use reflection to inspect number of arguments expected by this callback. + // We did some careful benchmarking here: Using reflection to avoid unneeded + // function arguments is actually faster than blindly passing them. + // Also, this helps avoiding unnecessary function arguments in the call stack + // if the callback creates an Exception (creating garbage cycles). + if (\is_array($callback)) { + $ref = new \ReflectionMethod($callback[0], $callback[1]); + } elseif (\is_object($callback) && !$callback instanceof \Closure) { + $ref = new \ReflectionMethod($callback, '__invoke'); + } else { + $ref = new \ReflectionFunction($callback); + } + $args = $ref->getNumberOfParameters(); + + try { + if ($args === 0) { + $callback(); + } else { + // Keep references to this promise instance for the static resolve/reject functions. + // By using static callbacks that are not bound to this instance + // and passing the target promise instance by reference, we can + // still execute its resolving logic and still clear this + // reference when settling the promise. This helps avoiding + // garbage cycles if any callback creates an Exception. + // These assumptions are covered by the test suite, so if you ever feel like + // refactoring this, go ahead, any alternative suggestions are welcome! + $target =& $this; + $progressHandlers =& $this->progressHandlers; + + $callback( + static function ($value = null) use (&$target) { + if ($target !== null) { + $target->settle(resolve($value)); + $target = null; + } + }, + static function ($reason = null) use (&$target) { + if ($target !== null) { + $target->reject($reason); + $target = null; + } + }, + static function ($update = null) use (&$progressHandlers) { + foreach ($progressHandlers as $handler) { + $handler($update); + } + } + ); + } + } catch (\Throwable $e) { + $target = null; + $this->reject($e); + } catch (\Exception $e) { + $target = null; + $this->reject($e); + } + } +} |