mirror of
https://github.com/danog/amp.git
synced 2024-12-13 01:47:33 +01:00
1036 lines
31 KiB
PHP
1036 lines
31 KiB
PHP
<?php
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namespace Amp
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{
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use React\Promise\PromiseInterface as ReactPromise;
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/**
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* Returns a new function that wraps $callback in a promise/coroutine-aware function that automatically runs
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* Generators as coroutines. The returned function always returns a promise when invoked. Errors have to be handled
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* by the callback caller or they will go unnoticed.
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*
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* Use this function to create a coroutine-aware callable for a promise-aware callback caller.
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*
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* @template TReturn
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* @template TPromise
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* @template TGeneratorReturn
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* @template TGeneratorPromise
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*
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* @template TGenerator as TGeneratorReturn|Promise<TGeneratorPromise>
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* @template T as TReturn|Promise<TPromise>|\Generator<mixed, mixed, mixed, TGenerator>
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*
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* @formatter:off
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*
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* @param callable(...mixed): T $callback
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*
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* @return callable
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* @psalm-return (T is Promise ? (callable(mixed...): Promise<TPromise>) : (T is \Generator ? (TGenerator is Promise ? (callable(mixed...): Promise<TGeneratorPromise>) : (callable(mixed...): Promise<TGeneratorReturn>)) : (callable(mixed...): Promise<TReturn>)))
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*
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* @formatter:on
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*
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* @see asyncCoroutine()
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*
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* @psalm-suppress InvalidReturnType
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*/
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function coroutine(callable $callback): callable
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{
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/** @psalm-suppress InvalidReturnStatement */
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return static function (...$args) use ($callback): Promise {
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return call($callback, ...$args);
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};
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}
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/**
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* Returns a new function that wraps $callback in a promise/coroutine-aware function that automatically runs
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* Generators as coroutines. The returned function always returns void when invoked. Errors are forwarded to the
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* loop's error handler using `Amp\Promise\rethrow()`.
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*
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* Use this function to create a coroutine-aware callable for a non-promise-aware callback caller.
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*
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* @param callable(...mixed): mixed $callback
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*
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* @return callable
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* @psalm-return callable(mixed...): void
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*
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* @see coroutine()
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*/
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function asyncCoroutine(callable $callback): callable
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{
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return static function (...$args) use ($callback) {
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Promise\rethrow(call($callback, ...$args));
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};
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}
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/**
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* Calls the given function, always returning a promise. If the function returns a Generator, it will be run as a
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* coroutine. If the function throws, a failed promise will be returned.
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*
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* @template TReturn
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* @template TPromise
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* @template TGeneratorReturn
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* @template TGeneratorPromise
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*
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* @template TGenerator as TGeneratorReturn|Promise<TGeneratorPromise>
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* @template T as TReturn|Promise<TPromise>|\Generator<mixed, mixed, mixed, TGenerator>
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*
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* @formatter:off
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*
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* @param callable(...mixed): T $callback
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* @param mixed ...$args Arguments to pass to the function.
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*
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* @return Promise
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* @psalm-return (T is Promise ? Promise<TPromise> : (T is \Generator ? (TGenerator is Promise ? Promise<TGeneratorPromise> : Promise<TGeneratorReturn>) : Promise<TReturn>))
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*
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* @formatter:on
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*/
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function call(callable $callback, ...$args): Promise
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{
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try {
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$result = $callback(...$args);
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} catch (\Throwable $exception) {
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return new Failure($exception);
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}
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if ($result instanceof \Generator) {
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return new Coroutine($result);
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}
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if ($result instanceof Promise) {
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return $result;
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}
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if ($result instanceof ReactPromise) {
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return Promise\adapt($result);
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}
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return new Success($result);
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}
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/**
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* Calls the given function. If the function returns a Generator, it will be run as a coroutine. If the function
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* throws or returns a failing promise, the failure is forwarded to the loop error handler.
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*
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* @param callable(...mixed): mixed $callback
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* @param mixed ...$args Arguments to pass to the function.
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*
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* @return void
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*/
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function asyncCall(callable $callback, ...$args)
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{
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Promise\rethrow(call($callback, ...$args));
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}
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/**
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* Sleeps for the specified number of milliseconds.
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*
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* @param int $milliseconds
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*
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* @return Delayed
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*/
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function delay(int $milliseconds): Delayed
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{
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return new Delayed($milliseconds);
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}
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/**
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* Returns the current time relative to an arbitrary point in time.
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*
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* @return int Time in milliseconds.
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*/
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function getCurrentTime(): int
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{
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return Internal\getCurrentTime();
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}
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}
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namespace Amp\Promise
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{
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use Amp\Deferred;
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use Amp\Loop;
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use Amp\MultiReasonException;
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use Amp\Promise;
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use Amp\Success;
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use Amp\TimeoutException;
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use React\Promise\PromiseInterface as ReactPromise;
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use function Amp\call;
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use function Amp\Internal\createTypeError;
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/**
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* Registers a callback that will forward the failure reason to the event loop's error handler if the promise fails.
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*
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* Use this function if you neither return the promise nor handle a possible error yourself to prevent errors from
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* going entirely unnoticed.
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*
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* @param Promise|ReactPromise $promise Promise to register the handler on.
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*
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* @return void
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* @throws \TypeError If $promise is not an instance of \Amp\Promise or \React\Promise\PromiseInterface.
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*
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*/
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function rethrow($promise)
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{
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if (!$promise instanceof Promise) {
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if ($promise instanceof ReactPromise) {
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$promise = adapt($promise);
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} else {
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throw createTypeError([Promise::class, ReactPromise::class], $promise);
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}
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}
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$promise->onResolve(static function ($exception) {
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if ($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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* Runs the event loop until the promise is resolved. Should not be called within a running event loop.
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*
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* Use this function only in synchronous contexts to wait for an asynchronous operation. Use coroutines and yield to
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* await promise resolution in a fully asynchronous application instead.
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*
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* @template TPromise
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* @template T as Promise<TPromise>|ReactPromise
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*
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* @param Promise|ReactPromise $promise Promise to wait for.
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*
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* @return mixed Promise success value.
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*
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* @psalm-param T $promise
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* @psalm-return (T is Promise ? TPromise : mixed)
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*
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* @throws \TypeError If $promise is not an instance of \Amp\Promise or \React\Promise\PromiseInterface.
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* @throws \Error If the event loop stopped without the $promise being resolved.
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* @throws \Throwable Promise failure reason.
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*/
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function wait($promise)
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{
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if (!$promise instanceof Promise) {
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if ($promise instanceof ReactPromise) {
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$promise = adapt($promise);
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} else {
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throw createTypeError([Promise::class, ReactPromise::class], $promise);
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}
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}
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$resolved = false;
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try {
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Loop::run(function () use (&$resolved, &$value, &$exception, $promise) {
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$promise->onResolve(function ($e, $v) use (&$resolved, &$value, &$exception) {
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Loop::stop();
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$resolved = true;
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$exception = $e;
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$value = $v;
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});
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});
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} catch (\Throwable $throwable) {
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throw new \Error("Loop exceptionally stopped without resolving the promise", 0, $throwable);
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}
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if (!$resolved) {
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throw new \Error("Loop stopped without resolving the promise");
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}
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if ($exception) {
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throw $exception;
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}
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return $value;
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}
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/**
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* Creates an artificial timeout for any `Promise`.
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*
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* If the timeout expires before the promise is resolved, the returned promise fails with an instance of
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* `Amp\TimeoutException`.
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*
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* @template TReturn
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*
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* @param Promise<TReturn>|ReactPromise $promise Promise to which the timeout is applied.
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* @param int $timeout Timeout in milliseconds.
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*
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* @return Promise<TReturn>
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*
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* @throws \TypeError If $promise is not an instance of \Amp\Promise or \React\Promise\PromiseInterface.
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*/
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function timeout($promise, int $timeout): Promise
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{
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if (!$promise instanceof Promise) {
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if ($promise instanceof ReactPromise) {
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$promise = adapt($promise);
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} else {
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throw createTypeError([Promise::class, ReactPromise::class], $promise);
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}
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}
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$deferred = new Deferred;
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$watcher = Loop::delay($timeout, static function () use (&$deferred) {
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$temp = $deferred; // prevent double resolve
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$deferred = null;
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$temp->fail(new TimeoutException);
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});
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Loop::unreference($watcher);
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$promise->onResolve(function () use (&$deferred, $promise, $watcher) {
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if ($deferred !== null) {
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Loop::cancel($watcher);
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$deferred->resolve($promise);
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}
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});
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return $deferred->promise();
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}
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/**
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* Creates an artificial timeout for any `Promise`.
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*
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* If the promise is resolved before the timeout expires, the result is returned
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*
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* If the timeout expires before the promise is resolved, a default value is returned
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*
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* @template TReturn
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*
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* @param Promise<TReturn>|ReactPromise $promise Promise to which the timeout is applied.
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* @param int $timeout Timeout in milliseconds.
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* @param TReturn $default
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*
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* @return Promise<TReturn>
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*
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* @throws \TypeError If $promise is not an instance of \Amp\Promise or \React\Promise\PromiseInterface.
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*/
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function timeoutWithDefault($promise, int $timeout, $default = null): Promise
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{
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$promise = timeout($promise, $timeout);
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return call(static function () use ($promise, $default) {
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try {
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return yield $promise;
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} catch (TimeoutException $exception) {
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return $default;
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}
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});
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}
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/**
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* Adapts any object with a done(callable $onFulfilled, callable $onRejected) or then(callable $onFulfilled,
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* callable $onRejected) method to a promise usable by components depending on placeholders implementing
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* \AsyncInterop\Promise.
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*
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* @param object $promise Object with a done() or then() method.
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*
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* @return Promise Promise resolved by the $thenable object.
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*
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* @throws \Error If the provided object does not have a then() method.
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*/
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function adapt($promise): Promise
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{
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$deferred = new Deferred;
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if (\method_exists($promise, 'done')) {
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$promise->done([$deferred, 'resolve'], [$deferred, 'fail']);
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} elseif (\method_exists($promise, 'then')) {
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$promise->then([$deferred, 'resolve'], [$deferred, 'fail']);
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} else {
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throw new \Error("Object must have a 'then' or 'done' method");
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}
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return $deferred->promise();
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}
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/**
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* Returns a promise that is resolved when all promises are resolved. The returned promise will not fail.
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* Returned promise succeeds with a two-item array delineating successful and failed promise results,
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* with keys identical and corresponding to the original given array.
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*
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* This function is the same as some() with the notable exception that it will never fail even
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* if all promises in the array resolve unsuccessfully.
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*
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* @param Promise[]|ReactPromise[] $promises
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*
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* @return Promise
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*
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* @throws \Error If a non-Promise is in the array.
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*/
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function any(array $promises): Promise
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{
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return some($promises, 0);
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}
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/**
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* Returns a promise that succeeds when all promises succeed, and fails if any promise fails. Returned
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* promise succeeds with an array of values used to succeed each contained promise, with keys corresponding to
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* the array of promises.
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*
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* @param Promise[]|ReactPromise[] $promises Array of only promises.
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*
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* @return Promise
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*
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* @throws \Error If a non-Promise is in the array.
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*
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* @template TValue
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*
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* @psalm-param array<array-key, Promise<TValue>|ReactPromise> $promises
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* @psalm-assert array<array-key, Promise<TValue>|ReactPromise> $promises $promises
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* @psalm-return Promise<array<array-key, TValue>>
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*/
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function all(array $promises): Promise
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{
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if (empty($promises)) {
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return new Success([]);
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}
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$deferred = new Deferred;
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$result = $deferred->promise();
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$pending = \count($promises);
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$values = [];
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foreach ($promises as $key => $promise) {
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if ($promise instanceof ReactPromise) {
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$promise = adapt($promise);
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} elseif (!$promise instanceof Promise) {
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throw createTypeError([Promise::class, ReactPromise::class], $promise);
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}
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$values[$key] = null; // add entry to array to preserve order
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$promise->onResolve(function ($exception, $value) use (&$deferred, &$values, &$pending, $key) {
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if ($pending === 0) {
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return;
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}
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if ($exception) {
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$pending = 0;
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$deferred->fail($exception);
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$deferred = null;
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return;
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}
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$values[$key] = $value;
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if (0 === --$pending) {
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$deferred->resolve($values);
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}
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});
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}
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return $result;
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}
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/**
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* Returns a promise that succeeds when the first promise succeeds, and fails only if all promises fail.
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*
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* @param Promise[]|ReactPromise[] $promises Array of only promises.
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*
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* @return Promise
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*
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* @throws \Error If the array is empty or a non-Promise is in the array.
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*/
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function first(array $promises): Promise
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{
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if (empty($promises)) {
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throw new \Error("No promises provided");
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}
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$deferred = new Deferred;
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$result = $deferred->promise();
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$pending = \count($promises);
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$exceptions = [];
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foreach ($promises as $key => $promise) {
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if ($promise instanceof ReactPromise) {
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$promise = adapt($promise);
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} elseif (!$promise instanceof Promise) {
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throw createTypeError([Promise::class, ReactPromise::class], $promise);
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}
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$exceptions[$key] = null; // add entry to array to preserve order
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$promise->onResolve(function ($error, $value) use (&$deferred, &$exceptions, &$pending, $key) {
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if ($pending === 0) {
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return;
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}
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if (!$error) {
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$pending = 0;
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$deferred->resolve($value);
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$deferred = null;
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return;
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}
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$exceptions[$key] = $error;
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if (0 === --$pending) {
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$deferred->fail(new MultiReasonException($exceptions));
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}
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});
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}
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return $result;
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}
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/**
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* Resolves with a two-item array delineating successful and failed Promise results.
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*
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* The returned promise will only fail if the given number of required promises fail.
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*
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* @param Promise[]|ReactPromise[] $promises Array of only promises.
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* @param int $required Number of promises that must succeed for the
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* returned promise to succeed.
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*
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* @return Promise
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*
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* @throws \Error If a non-Promise is in the array.
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*/
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function some(array $promises, int $required = 1): Promise
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{
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if ($required < 0) {
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throw new \Error("Number of promises required must be non-negative");
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}
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$pending = \count($promises);
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if ($required > $pending) {
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throw new \Error("Too few promises provided");
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}
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|
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if (empty($promises)) {
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return new Success([[], []]);
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}
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$deferred = new Deferred;
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$result = $deferred->promise();
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$values = [];
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$exceptions = [];
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|
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foreach ($promises as $key => $promise) {
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if ($promise instanceof ReactPromise) {
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$promise = adapt($promise);
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} elseif (!$promise instanceof Promise) {
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throw createTypeError([Promise::class, ReactPromise::class], $promise);
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}
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$values[$key] = $exceptions[$key] = null; // add entry to arrays to preserve order
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$promise->onResolve(static function ($exception, $value) use (
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&$values,
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&$exceptions,
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&$pending,
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$key,
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$required,
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$deferred
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) {
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if ($exception) {
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$exceptions[$key] = $exception;
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unset($values[$key]);
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} else {
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$values[$key] = $value;
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unset($exceptions[$key]);
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}
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|
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if (0 === --$pending) {
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if (\count($values) < $required) {
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$deferred->fail(new MultiReasonException($exceptions));
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} else {
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$deferred->resolve([$exceptions, $values]);
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}
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}
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});
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}
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return $result;
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}
|
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|
|
/**
|
|
* Wraps a promise into another promise, altering the exception or result.
|
|
*
|
|
* @param Promise|ReactPromise $promise
|
|
* @param callable $callback
|
|
*
|
|
* @return Promise
|
|
*/
|
|
function wrap($promise, callable $callback): Promise
|
|
{
|
|
if ($promise instanceof ReactPromise) {
|
|
$promise = adapt($promise);
|
|
} elseif (!$promise instanceof Promise) {
|
|
throw createTypeError([Promise::class, ReactPromise::class], $promise);
|
|
}
|
|
|
|
$deferred = new Deferred();
|
|
|
|
$promise->onResolve(static function (\Throwable $exception = null, $result) use ($deferred, $callback) {
|
|
try {
|
|
$result = $callback($exception, $result);
|
|
} catch (\Throwable $exception) {
|
|
$deferred->fail($exception);
|
|
|
|
return;
|
|
}
|
|
|
|
$deferred->resolve($result);
|
|
});
|
|
|
|
return $deferred->promise();
|
|
}
|
|
}
|
|
|
|
namespace Amp\Iterator
|
|
{
|
|
use Amp\Delayed;
|
|
use Amp\Emitter;
|
|
use Amp\Iterator;
|
|
use Amp\Producer;
|
|
use Amp\Promise;
|
|
use Amp\Stream;
|
|
use function Amp\call;
|
|
use function Amp\coroutine;
|
|
use function Amp\Internal\createTypeError;
|
|
|
|
/**
|
|
* Creates an iterator from the given iterable, emitting the each value. The iterable may contain promises. If any
|
|
* promise fails, the iterator will fail with the same reason.
|
|
*
|
|
* @param array|\Traversable $iterable Elements to emit.
|
|
* @param int $delay Delay between element emissions in milliseconds.
|
|
*
|
|
* @return Iterator
|
|
*
|
|
* @throws \TypeError If the argument is not an array or instance of \Traversable.
|
|
*/
|
|
function fromIterable(/* iterable */
|
|
$iterable,
|
|
int $delay = 0
|
|
): Iterator {
|
|
if (!$iterable instanceof \Traversable && !\is_array($iterable)) {
|
|
throw createTypeError(["array", "Traversable"], $iterable);
|
|
}
|
|
|
|
if ($delay) {
|
|
return new Producer(static function (callable $emit) use ($iterable, $delay) {
|
|
foreach ($iterable as $value) {
|
|
yield new Delayed($delay);
|
|
yield $emit($value);
|
|
}
|
|
});
|
|
}
|
|
|
|
return new Producer(static function (callable $emit) use ($iterable) {
|
|
foreach ($iterable as $value) {
|
|
yield $emit($value);
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* @template TValue
|
|
* @template TReturn
|
|
*
|
|
* @param Iterator<TValue> $iterator
|
|
* @param callable (TValue $value): TReturn $onEmit
|
|
*
|
|
* @return Iterator<TReturn>
|
|
*/
|
|
function map(Iterator $iterator, callable $onEmit): Iterator
|
|
{
|
|
return new Producer(static function (callable $emit) use ($iterator, $onEmit) {
|
|
while (yield $iterator->advance()) {
|
|
yield $emit($onEmit($iterator->getCurrent()));
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* @template TValue
|
|
*
|
|
* @param Iterator<TValue> $iterator
|
|
* @param callable(TValue $value):bool $filter
|
|
*
|
|
* @return Iterator<TValue>
|
|
*/
|
|
function filter(Iterator $iterator, callable $filter): Iterator
|
|
{
|
|
return new Producer(static function (callable $emit) use ($iterator, $filter) {
|
|
while (yield $iterator->advance()) {
|
|
if ($filter($iterator->getCurrent())) {
|
|
yield $emit($iterator->getCurrent());
|
|
}
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Creates an iterator that emits values emitted from any iterator in the array of iterators.
|
|
*
|
|
* @param Iterator[] $iterators
|
|
*
|
|
* @return Iterator
|
|
*/
|
|
function merge(array $iterators): Iterator
|
|
{
|
|
$emitter = new Emitter;
|
|
$result = $emitter->iterate();
|
|
|
|
$coroutine = coroutine(static function (Iterator $iterator) use (&$emitter) {
|
|
while ((yield $iterator->advance()) && $emitter !== null) {
|
|
yield $emitter->emit($iterator->getCurrent());
|
|
}
|
|
});
|
|
|
|
$coroutines = [];
|
|
foreach ($iterators as $iterator) {
|
|
if (!$iterator instanceof Iterator) {
|
|
throw createTypeError([Iterator::class], $iterator);
|
|
}
|
|
|
|
$coroutines[] = $coroutine($iterator);
|
|
}
|
|
|
|
Promise\all($coroutines)->onResolve(static function ($exception) use (&$emitter) {
|
|
if ($exception) {
|
|
$emitter->fail($exception);
|
|
$emitter = null;
|
|
} else {
|
|
$emitter->complete();
|
|
}
|
|
});
|
|
|
|
return $result;
|
|
}
|
|
|
|
/**
|
|
* Concatenates the given iterators into a single iterator, emitting values from a single iterator at a time. The
|
|
* prior iterator must complete before values are emitted from any subsequent iterators. Iterators are concatenated
|
|
* in the order given (iteration order of the array).
|
|
*
|
|
* @param Iterator[] $iterators
|
|
*
|
|
* @return Iterator
|
|
*/
|
|
function concat(array $iterators): Iterator
|
|
{
|
|
foreach ($iterators as $iterator) {
|
|
if (!$iterator instanceof Iterator) {
|
|
throw createTypeError([Iterator::class], $iterator);
|
|
}
|
|
}
|
|
|
|
return new Producer(function (callable $emit) use ($iterators) {
|
|
foreach ($iterators as $iterator) {
|
|
while (yield $iterator->advance()) {
|
|
yield $emit($iterator->getCurrent());
|
|
}
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Discards all remaining items and returns the number of discarded items.
|
|
*
|
|
* @template TValue
|
|
*
|
|
* @param Iterator $iterator
|
|
*
|
|
* @return Promise
|
|
*
|
|
* @psalm-param Iterator<TValue> $iterator
|
|
* @psalm-return Promise<int>
|
|
*/
|
|
function discard(Iterator $iterator): Promise
|
|
{
|
|
return call(static function () use ($iterator): \Generator {
|
|
$count = 0;
|
|
|
|
while (yield $iterator->advance()) {
|
|
$count++;
|
|
}
|
|
|
|
return $count;
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Collects all items from an iterator into an array.
|
|
*
|
|
* @template TValue
|
|
*
|
|
* @param Iterator $iterator
|
|
*
|
|
* @psalm-param Iterator<TValue> $iterator
|
|
*
|
|
* @return Promise
|
|
* @psalm-return Promise<array<int, TValue>>
|
|
*/
|
|
function toArray(Iterator $iterator): Promise
|
|
{
|
|
return call(static function () use ($iterator): \Generator {
|
|
/** @psalm-var list $array */
|
|
$array = [];
|
|
|
|
while (yield $iterator->advance()) {
|
|
$array[] = $iterator->getCurrent();
|
|
}
|
|
|
|
return $array;
|
|
});
|
|
}
|
|
|
|
/**
|
|
* @template TValue
|
|
*
|
|
* @param Stream $stream
|
|
*
|
|
* @psalm-param Stream<TValue> $stream
|
|
*
|
|
* @return Iterator
|
|
*
|
|
* @psalm-return Iterator<TValue>
|
|
*/
|
|
function fromStream(Stream $stream): Iterator
|
|
{
|
|
return new Producer(function (callable $emit) use ($stream): \Generator {
|
|
while (null !== $value = yield $stream->continue()) {
|
|
yield $emit($value);
|
|
}
|
|
});
|
|
}
|
|
}
|
|
|
|
namespace Amp\Stream
|
|
{
|
|
use Amp\AsyncGenerator;
|
|
use Amp\Delayed;
|
|
use Amp\Iterator;
|
|
use Amp\Promise;
|
|
use Amp\Stream;
|
|
use Amp\StreamSource;
|
|
use React\Promise\PromiseInterface as ReactPromise;
|
|
use function Amp\call;
|
|
use function Amp\coroutine;
|
|
use function Amp\Internal\createTypeError;
|
|
|
|
/**
|
|
* Creates a stream from the given iterable, emitting the each value. The iterable may contain promises. If any
|
|
* promise fails, the returned stream will fail with the same reason.
|
|
*
|
|
* @template TValue
|
|
*
|
|
* @param array|\Traversable $iterable Elements to emit.
|
|
* @param int $delay Delay between elements emitted in milliseconds.
|
|
*
|
|
* @psalm-param iterable<TValue> $iterable
|
|
*
|
|
* @return Stream
|
|
*
|
|
* @psalm-return Stream<TValue>
|
|
*
|
|
* @throws \TypeError If the argument is not an array or instance of \Traversable.
|
|
*/
|
|
function fromIterable(/* iterable */
|
|
$iterable,
|
|
int $delay = 0
|
|
): Stream {
|
|
if (!$iterable instanceof \Traversable && !\is_array($iterable)) {
|
|
throw createTypeError(["array", "Traversable"], $iterable);
|
|
}
|
|
|
|
return new AsyncGenerator(static function (callable $yield) use ($iterable, $delay) {
|
|
foreach ($iterable as $value) {
|
|
if ($delay) {
|
|
yield new Delayed($delay);
|
|
}
|
|
|
|
if ($value instanceof Promise || $value instanceof ReactPromise) {
|
|
$value = yield $value;
|
|
}
|
|
|
|
yield $yield($value);
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* @template TValue
|
|
* @template TReturn
|
|
*
|
|
* @param Stream $stream
|
|
* @param callable(TValue $value):TReturn $onEmit
|
|
*
|
|
* @psalm-param Stream<TValue> $stream
|
|
*
|
|
* @return Stream
|
|
*
|
|
* @psalm-return Stream<TReturn>
|
|
*/
|
|
function map(Stream $stream, callable $onEmit): Stream
|
|
{
|
|
return new AsyncGenerator(static function (callable $yield) use ($stream, $onEmit) {
|
|
while (null !== $value = yield $stream->continue()) {
|
|
yield $yield(yield call($onEmit, $value));
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* @template TValue
|
|
*
|
|
* @param Stream $stream
|
|
* @param callable(TValue $value):bool $filter
|
|
*
|
|
* @psalm-param Stream<TValue> $stream
|
|
*
|
|
* @return Stream
|
|
*
|
|
* @psalm-return Stream<TValue>
|
|
*/
|
|
function filter(Stream $stream, callable $filter): Stream
|
|
{
|
|
return new AsyncGenerator(static function (callable $yield) use ($stream, $filter) {
|
|
while (null !== $value = yield $stream->continue()) {
|
|
if (yield call($filter, $value)) {
|
|
yield $yield($value);
|
|
}
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Creates a stream that emits values emitted from any stream in the array of streams.
|
|
*
|
|
* @param Stream[] $streams
|
|
*
|
|
* @return Stream
|
|
*/
|
|
function merge(array $streams): Stream
|
|
{
|
|
$source = new StreamSource;
|
|
$result = $source->stream();
|
|
|
|
$coroutine = coroutine(static function (Stream $stream) use (&$source) {
|
|
while ((null !== $value = yield $stream->continue()) && $source !== null) {
|
|
yield $source->emit($value);
|
|
}
|
|
});
|
|
|
|
$coroutines = [];
|
|
foreach ($streams as $stream) {
|
|
if (!$stream instanceof Stream) {
|
|
throw createTypeError([Stream::class], $stream);
|
|
}
|
|
|
|
$coroutines[] = $coroutine($stream);
|
|
}
|
|
|
|
Promise\all($coroutines)->onResolve(static function ($exception) use (&$source) {
|
|
$temp = $source;
|
|
$source = null;
|
|
|
|
if ($exception) {
|
|
$temp->fail($exception);
|
|
} else {
|
|
$temp->complete();
|
|
}
|
|
});
|
|
|
|
return $result;
|
|
}
|
|
|
|
/**
|
|
* Concatenates the given streams into a single stream, emitting from a single stream at a time. The
|
|
* prior stream must complete before values are emitted from any subsequent streams. Streams are concatenated
|
|
* in the order given (iteration order of the array).
|
|
*
|
|
* @param Stream[] $streams
|
|
*
|
|
* @return Stream
|
|
*/
|
|
function concat(array $streams): Stream
|
|
{
|
|
foreach ($streams as $stream) {
|
|
if (!$stream instanceof Stream) {
|
|
throw createTypeError([Stream::class], $stream);
|
|
}
|
|
}
|
|
|
|
return new AsyncGenerator(function (callable $emit) use ($streams) {
|
|
foreach ($streams as $stream) {
|
|
while ($value = yield $stream->continue()) {
|
|
yield $emit($value);
|
|
}
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Discards all remaining items and returns the number of discarded items.
|
|
*
|
|
* @template TValue
|
|
*
|
|
* @param Stream $stream
|
|
*
|
|
* @psalm-param Stream<TValue> $stream
|
|
*
|
|
* @return Promise<int>
|
|
*/
|
|
function discard(Stream $stream): Promise
|
|
{
|
|
return call(static function () use ($stream): \Generator {
|
|
$count = 0;
|
|
|
|
while (null !== yield $stream->continue()) {
|
|
$count++;
|
|
}
|
|
|
|
return $count;
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Collects all items from a stream into an array.
|
|
*
|
|
* @template TValue
|
|
*
|
|
* @param Stream $stream
|
|
*
|
|
* @psalm-param Stream<TValue> $stream
|
|
*
|
|
* @return Promise
|
|
*
|
|
* @psalm-return Promise<array<int, TValue>>
|
|
*/
|
|
function toArray(Stream $stream): Promise
|
|
{
|
|
return call(static function () use ($stream): \Generator {
|
|
/** @psalm-var list<TValue> $array */
|
|
$array = [];
|
|
|
|
while (null !== $value = yield $stream->continue()) {
|
|
$array[] = $value;
|
|
}
|
|
|
|
return $array;
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Converts an instance of the deprecated {@see Iterator} into an instance of {@see Stream}.
|
|
*
|
|
* @template TValue
|
|
*
|
|
* @param Iterator $iterator
|
|
*
|
|
* @psalm-param Iterator<TValue> $iterator
|
|
*
|
|
* @return Stream
|
|
*
|
|
* @psalm-return Stream<TValue>
|
|
*/
|
|
function fromIterator(Iterator $iterator): Stream
|
|
{
|
|
return new AsyncGenerator(function (callable $yield) use ($iterator): \Generator {
|
|
while (yield $iterator->advance()) {
|
|
yield $yield($iterator->getCurrent());
|
|
}
|
|
});
|
|
}
|
|
}
|