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a75164b66b
This also fixes mixed types in some cases.
178 lines
4.9 KiB
PHP
178 lines
4.9 KiB
PHP
<?php
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namespace Amp\Internal;
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use Amp\Coroutine;
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use Amp\Failure;
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use Amp\Loop;
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use Amp\Promise;
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use React\Promise\PromiseInterface as ReactPromise;
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/**
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* Trait used by Promise implementations. Do not use this trait in your code, instead compose your class from one of
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* the available classes implementing \Amp\Promise.
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*
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* @internal
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*/
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trait Placeholder
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{
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/** @var bool */
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private $resolved = false;
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/** @var mixed */
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private $result;
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/** @var ResolutionQueue|null|callable(\Throwable|null, mixed): (Promise|\React\Promise\PromiseInterface|\Generator<mixed,
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* Promise|\React\Promise\PromiseInterface|array<array-key, Promise|\React\Promise\PromiseInterface>, mixed,
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* mixed>|null)|callable(\Throwable|null, mixed): void */
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private $onResolved;
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/** @var null|array */
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private $resolutionTrace;
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/**
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* @inheritdoc
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*/
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public function onResolve(callable $onResolved)
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{
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if ($this->resolved) {
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if ($this->result instanceof Promise) {
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$this->result->onResolve($onResolved);
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return;
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}
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try {
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/** @var mixed $result */
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$result = $onResolved(null, $this->result);
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if ($result === null) {
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return;
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}
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if ($result instanceof \Generator) {
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$result = new Coroutine($result);
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}
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if ($result instanceof Promise || $result instanceof ReactPromise) {
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Promise\rethrow($result);
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}
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} catch (\Throwable $exception) {
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Loop::defer(static function () use ($exception) {
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throw $exception;
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});
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}
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return;
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}
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if (null === $this->onResolved) {
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$this->onResolved = $onResolved;
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return;
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}
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if (!$this->onResolved instanceof ResolutionQueue) {
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$this->onResolved = new ResolutionQueue($this->onResolved);
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}
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$this->onResolved->push($onResolved);
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}
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public function __destruct()
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{
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try {
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$this->result = null;
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} catch (\Throwable $e) {
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Loop::defer(static function () use ($e) {
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throw $e;
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});
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}
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}
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/**
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* @param mixed $value
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*
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* @return void
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*
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* @throws \Error Thrown if the promise has already been resolved.
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*/
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private function resolve($value = null)
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{
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if ($this->resolved) {
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$message = "Promise has already been resolved";
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if (isset($this->resolutionTrace)) {
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$trace = formatStacktrace($this->resolutionTrace);
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$message .= ". Previous resolution trace:\n\n{$trace}\n\n";
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} else {
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// @codeCoverageIgnoreStart
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$message .= ", define environment variable AMP_DEBUG or const AMP_DEBUG = true and enable assertions "
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. "for a stacktrace of the previous resolution.";
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// @codeCoverageIgnoreEnd
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}
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throw new \Error($message);
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}
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\assert((function () {
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$env = \getenv("AMP_DEBUG") ?: "0";
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if (($env !== "0" && $env !== "false") || (\defined("AMP_DEBUG") && \AMP_DEBUG)) {
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$trace = \debug_backtrace(\DEBUG_BACKTRACE_IGNORE_ARGS);
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\array_shift($trace); // remove current closure
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$this->resolutionTrace = $trace;
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}
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return true;
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})());
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if ($value instanceof ReactPromise) {
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$value = Promise\adapt($value);
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}
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$this->resolved = true;
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$this->result = $value;
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if ($this->onResolved === null) {
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return;
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}
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$onResolved = $this->onResolved;
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$this->onResolved = null;
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if ($this->result instanceof Promise) {
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$this->result->onResolve($onResolved);
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return;
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}
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try {
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/** @var mixed $result */
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$result = $onResolved(null, $this->result);
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$onResolved = null; // allow garbage collection of $onResolved, to catch any exceptions from destructors
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if ($result === null) {
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return;
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}
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if ($result instanceof \Generator) {
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$result = new Coroutine($result);
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}
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if ($result instanceof Promise || $result instanceof ReactPromise) {
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Promise\rethrow($result);
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}
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} catch (\Throwable $exception) {
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Loop::defer(static function () use ($exception) {
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throw $exception;
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});
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}
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}
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/**
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* @param \Throwable $reason Failure reason.
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*
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* @return void
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*/
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private function fail(\Throwable $reason)
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{
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$this->resolve(new Failure($reason));
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}
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}
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