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mirror of https://github.com/danog/amp.git synced 2024-12-11 08:59:46 +01:00
amp/lib/Internal/Placeholder.php
Niklas Keller a75164b66b Add psalm static analysis on level 6
This also fixes mixed types in some cases.
2020-03-28 12:23:46 +01:00

178 lines
4.9 KiB
PHP

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