Current File : /home2/selectio/www/fms-worksuite/vendor/amphp/amp/lib/Coroutine.php
<?php
namespace Amp;
use React\Promise\PromiseInterface as ReactPromise;
/**
* Creates a promise from a generator function yielding promises.
*
* When a promise is yielded, execution of the generator is interrupted until the promise is resolved. A success
* value is sent into the generator, while a failure reason is thrown into the generator. Using a coroutine,
* asynchronous code can be written without callbacks and be structured like synchronous code.
*
* @template-covariant TReturn
* @template-implements Promise<TReturn>
*/
final class Coroutine implements Promise
{
use Internal\Placeholder;
/**
* Attempts to transform the non-promise yielded from the generator into a promise, otherwise returns an instance
* `Amp\Failure` failed with an instance of `Amp\InvalidYieldError`.
*
* @param mixed $yielded Non-promise yielded from generator.
* @param \Generator $generator No type for performance, we already know the type.
*
* @return Promise
*/
private static function transform($yielded, $generator): Promise
{
$exception = null; // initialize here, see https://github.com/vimeo/psalm/issues/2951
try {
if (\is_array($yielded)) {
return Promise\all($yielded);
}
if ($yielded instanceof ReactPromise) {
return Promise\adapt($yielded);
}
// No match, continue to returning Failure below.
} catch (\Throwable $exception) {
// Conversion to promise failed, fall-through to returning Failure below.
}
return new Failure(new InvalidYieldError(
$generator,
\sprintf(
"Unexpected yield; Expected an instance of %s or %s or an array of such instances",
Promise::class,
ReactPromise::class
),
$exception
));
}
/**
* @param \Generator $generator
* @psalm-param \Generator<mixed,Promise|ReactPromise|array<array-key,
* Promise|ReactPromise>,mixed,Promise<TReturn>|ReactPromise|TReturn> $generator
*/
public function __construct(\Generator $generator)
{
try {
$yielded = $generator->current();
if (!$yielded instanceof Promise) {
if (!$generator->valid()) {
$this->resolve($generator->getReturn());
return;
}
$yielded = self::transform($yielded, $generator);
}
} catch (\Throwable $exception) {
$this->fail($exception);
return;
}
/**
* @param \Throwable|null $e Exception to be thrown into the generator.
* @param mixed $v Value to be sent into the generator.
*
* @return void
*
* @psalm-suppress MissingClosureParamType
* @psalm-suppress MissingClosureReturnType
*/
$onResolve = function (\Throwable $e = null, $v) use ($generator, &$onResolve) {
/** @var bool $immediate Used to control iterative coroutine continuation. */
static $immediate = true;
/** @var \Throwable|null $exception Promise failure reason when executing next coroutine step, null at all other times. */
static $exception;
/** @var mixed $value Promise success value when executing next coroutine step, null at all other times. */
static $value;
$exception = $e;
/** @psalm-suppress MixedAssignment */
$value = $v;
if (!$immediate) {
$immediate = true;
return;
}
try {
try {
do {
if ($exception) {
// Throw exception at current execution point.
$yielded = $generator->throw($exception);
} else {
// Send the new value and execute to next yield statement.
$yielded = $generator->send($value);
}
if (!$yielded instanceof Promise) {
if (!$generator->valid()) {
$this->resolve($generator->getReturn());
$onResolve = null;
return;
}
$yielded = self::transform($yielded, $generator);
}
$immediate = false;
$yielded->onResolve($onResolve);
} while ($immediate);
$immediate = true;
} catch (\Throwable $exception) {
$this->fail($exception);
$onResolve = null;
} finally {
$exception = null;
$value = null;
}
} catch (\Throwable $e) {
Loop::defer(static function () use ($e) {
throw $e;
});
}
};
try {
$yielded->onResolve($onResolve);
unset($generator, $yielded, $onResolve);
} catch (\Throwable $e) {
Loop::defer(static function () use ($e) {
throw $e;
});
}
}
}
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