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amp/lib/functions.php
2016-09-09 18:05:01 -05:00

989 lines
28 KiB
PHP

<?php declare(strict_types = 1);
namespace Amp;
use Interop\Async\{ Awaitable, Loop, Loop\Driver };
/**
* Execute a callback within the event loop scope.
* Returned Generators are run as coroutines. Failures of the coroutine are forwarded to the loop error handler.
*
* @see \Interop\Async\Loop::execute()
*
* @param callable $callback
* @param \Interop\Async\Loop\Driver|null $driver
*/
function execute(callable $callback, Driver $driver = null) {
Loop::execute(function () use ($callback) {
$result = $callback();
if ($result instanceof \Generator) {
rethrow(new Coroutine($result));
}
}, $driver);
}
/**
* Stops the event loop.
*
* @see \Interop\Async\Loop::stop()
*/
function stop() {
Loop::stop();
}
/**
* Execute a callback when a stream resource becomes readable.
* Returned Generators are run as coroutines. Failures of the coroutine are forwarded to the loop error handler.
*
* @see \Interop\Async\Loop::onReadable()
*
* @param resource $stream The stream to monitor.
* @param callable(string $watcherId, resource $stream, mixed $data) $callback The callback to execute.
* @param mixed $data
*
* @return string Watcher identifier.
*/
function onReadable($stream, callable $callback, $data = null): string {
return Loop::onReadable($stream, function ($watcherId, $stream, $data) use ($callback) {
$result = $callback($watcherId, $stream, $data);
if ($result instanceof \Generator) {
rethrow(new Coroutine($result));
return;
}
}, $data);
}
/**
* Execute a callback when a stream resource becomes writable.
* Returned Generators are run as coroutines. Failures of the coroutine are forwarded to the loop error handler.
*
* @see \Interop\Async\Loop::onWritable()
*
* @param resource $stream The stream to monitor.
* @param callable(string $watcherId, resource $stream, mixed $data) $callback The callback to execute.
* @param mixed $data
*
* @return string Watcher identifier.
*/
function onWritable($stream, callable $callback, $data = null): string {
return Loop::onWritable($stream, function ($watcherId, $stream, $data) use ($callback) {
$result = $callback($watcherId, $stream, $data);
if ($result instanceof \Generator) {
rethrow(new Coroutine($result));
}
}, $data);
}
/**
* Execute a callback when a signal is received.
* Returned Generators are run as coroutines. Failures of the coroutine are forwarded to the loop error handler.
*
* @see \Interop\Async\Loop::onSignal()
*
* @param int $signo The signal number to monitor.
* @param callable(string $watcherId, int $signo, mixed $data) $callback The callback to execute.
* @param mixed $data
*
* @return string Watcher identifier.
*/
function onSignal(int $signo, callable $callback, $data = null): string {
return Loop::onSignal($signo, function ($watcherId, $signo, $data) use ($callback) {
$result = $callback($watcherId, $signo, $data);
if ($result instanceof \Generator) {
rethrow(new Coroutine($result));
}
}, $data);
}
/**
* Defer the execution of a callback.
* Returned Generators are run as coroutines. Failures of the coroutine are forwarded to the loop error handler.
*
* @see \Interop\Async\Loop::defer()
*
* @param callable(string $watcherId, mixed $data) $callback The callback to delay.
* @param mixed $data
*
* @return string Watcher identifier.
*/
function defer(callable $callback, $data = null): string {
return Loop::defer(function ($watcherId, $data) use ($callback) {
$result = $callback($watcherId, $data);
if ($result instanceof \Generator) {
rethrow(new Coroutine($result));
}
}, $data);
}
/**
* Delay the execution of a callback.
* Returned Generators are run as coroutines. Failures of the coroutine are forwarded to the loop error handler.
*
* @see \Interop\Async\Loop::delay()
*
* @param int $time
* @param callable(string $watcherId, mixed $data) $callback The callback to delay.
* @param mixed $data
*
* @return string Watcher identifier.
*/
function delay(int $time, callable $callback, $data = null): string {
return Loop::delay($time, function ($watcherId, $data) use ($callback) {
$result = $callback($watcherId, $data);
if ($result instanceof \Generator) {
rethrow(new Coroutine($result));
}
}, $data);
}
/**
* Repeatedly execute a callback.
* Returned Generators are run as coroutines. Failures of the coroutine are forwarded to the loop error handler.
*
* @see \Interop\Async\Loop::repeat()
*
* @param int $time
* @param callable(string $watcherId, mixed $data) $callback The callback to delay.
* @param mixed $data
*
* @return string Watcher identifier.
*/
function repeat(int $time, callable $callback, $data = null): string {
return Loop::repeat($time, function ($watcherId, $data) use ($callback) {
$result = $callback($watcherId, $data);
if ($result instanceof \Generator) {
rethrow(new Coroutine($result));
}
}, $data);
}
/**
* Enable a watcher.
*
* @see \Interop\Async\Loop::enable()
*
* @param string $watcherId
*/
function enable(string $watcherId) {
Loop::enable($watcherId);
}
/**
* Disable a watcher.
*
* @see \Interop\Async\Loop::disable()
*
* @param string $watcherId
*/
function disable(string $watcherId) {
Loop::disable($watcherId);
}
/**
* Cancel a watcher.
*
* @see \Interop\Async\Loop::cancel()
*
* @param string $watcherId
*/
function cancel(string $watcherId) {
Loop::cancel($watcherId);
}
/**
* Reference a watcher.
*
* @see \Interop\Async\Loop::reference()
*
* @param string $watcherId
*/
function reference(string $watcherId) {
Loop::reference($watcherId);
}
/**
* Unreference a watcher.
*
* @see \Interop\Async\Loop::unreference()
*
* @param string $watcherId
*/
function unreference(string $watcherId) {
Loop::unreference($watcherId);
}
/**
* Returned Generators are run as coroutines. Failures of the coroutine are forwarded to the loop error handler.
*
* @see \Interop\Async\Loop::setErrorHandler()
*
* @param callable $callback
*/
function setErrorHandler(callable $callback) {
Loop::setErrorHandler(function ($exception) use ($callback) {
$result = $callback($exception);
if ($result instanceof \Generator) {
rethrow(new Coroutine($result));
}
});
}
/**
* Wraps the callback in an awaitable/coroutine-aware function that automatically upgrades Generators to coroutines and
* calls rethrow() on the created coroutine.
*
* @param callable(...$args): \Generator|\Interop\Async\Awaitable|mixed $callback
*
* @return callable(...$args): void
*/
function wrap(callable $callback): callable {
return function (...$args) use ($callback) {
$result = $callback(...$args);
if ($result instanceof \Generator) {
rethrow(new Coroutine($result));
}
};
}
/**
* Returns a new function that wraps $worker in a awaitable/coroutine-aware function that automatically upgrades
* Generators to coroutines. The returned function always returns an awaitable when invoked. If $worker throws, a failed
* awaitable is returned.
*
* @param callable(mixed ...$args): mixed $worker
*
* @return callable(mixed ...$args): \Interop\Async\Awaitable
*/
function coroutine(callable $worker): callable {
return function (...$args) use ($worker): Awaitable {
try {
$result = $worker(...$args);
} catch (\Throwable $exception) {
return new Failure($exception);
}
if ($result instanceof \Generator) {
return new Coroutine($result);
}
if (!$result instanceof Awaitable) {
return new Success($result);
}
return $result;
};
}
/**
* Registers a callback that will forward the failure reason to the Loop error handler if the awaitable fails.
*
* @param \Interop\Async\Awaitable $awaitable
*/
function rethrow(Awaitable $awaitable) {
$awaitable->when(function ($exception) {
if ($exception) {
throw $exception;
}
});
}
/**
* Runs the event loop until the awaitable is resolved. Should not be called within a running event loop.
*
* @param \Interop\Async\Awaitable $awaitable
*
* @return mixed Awaitable success value.
*
* @throws \Throwable Awaitable failure reason.
*/
function wait(Awaitable $awaitable) {
$resolved = false;
Loop::execute(function () use (&$resolved, &$value, &$exception, $awaitable) {
$awaitable->when(function ($e, $v) use (&$resolved, &$value, &$exception) {
Loop::stop();
$resolved = true;
$exception = $e;
$value = $v;
});
}, Loop::get());
if (!$resolved) {
throw new \Error("Loop emptied without resolving awaitable");
}
if ($exception) {
throw $exception;
}
return $value;
}
/**
* Pipe the promised value through the specified functor once it resolves.
*
* @param \Interop\Async\Awaitable $awaitable
* @param callable(mixed $value): mixed $functor
*
* @return \Interop\Async\Awaitable
*/
function pipe(Awaitable $awaitable, callable $functor): Awaitable {
$deferred = new Deferred;
$awaitable->when(function ($exception, $value) use ($deferred, $functor) {
if ($exception) {
$deferred->fail($exception);
return;
}
try {
$deferred->resolve($functor($value));
} catch (\Throwable $exception) {
$deferred->fail($exception);
}
});
return $deferred->getAwaitable();
}
/**
* @param \Interop\Async\Awaitable $awaitable
* @param string $className Exception class name to capture. Given callback will only be invoked if the failure reason
* is an instance of the given exception class name.
* @param callable(\Throwable $exception): mixed $functor
*
* @return \Interop\Async\Awaitable
*/
function capture(Awaitable $awaitable, string $className, callable $functor): Awaitable {
$deferred = new Deferred;
$awaitable->when(function ($exception, $value) use ($deferred, $className, $functor) {
if (!$exception) {
$deferred->resolve($value);
return;
}
if (!$exception instanceof $className) {
$deferred->fail($exception);
return;
}
try {
$deferred->resolve($functor($exception));
} catch (\Throwable $exception) {
$deferred->fail($exception);
}
});
return $deferred->getAwaitable();
}
/**
* Create an artificial timeout for any Awaitable.
*
* If the timeout expires before the awaitable is resolved, the returned awaitable fails with an instance of
* \Amp\TimeoutException.
*
* @param \Interop\Async\Awaitable $awaitable
* @param int $timeout Timeout in milliseconds.
*
* @return \Interop\Async\Awaitable
*/
function timeout(Awaitable $awaitable, int $timeout): Awaitable {
$deferred = new Deferred;
$resolved = false;
$watcher = Loop::delay($timeout, function () use (&$resolved, $deferred) {
if (!$resolved) {
$resolved = true;
$deferred->fail(new TimeoutException);
}
});
$awaitable->when(function () use (&$resolved, $awaitable, $deferred, $watcher) {
Loop::cancel($watcher);
if ($resolved) {
return;
}
$resolved = true;
$deferred->resolve($awaitable);
});
return $deferred->getAwaitable();
}
/**
* Returns a awaitable that calls $promisor only when the result of the awaitable is requested (e.g., then() or
* done() is called on the returned awaitable). $promisor can return a awaitable or any value. If $promisor throws
* an exception, the returned awaitable is rejected with that exception.
*
* @param callable $promisor
* @param mixed ...$args
*
* @return \Interop\Async\Awaitable
*/
function lazy(callable $promisor, ...$args): Awaitable {
if (empty($args)) {
return new Internal\LazyAwaitable($promisor);
}
return new Internal\LazyAwaitable(function () use ($promisor, $args) {
return $promisor(...$args);
});
}
/**
* Adapts any object with a then(callable $onFulfilled, callable $onRejected) method to a awaitable usable by
* components depending on placeholders implementing Awaitable.
*
* @param object $thenable Object with a then() method.
*
* @return \Interop\Async\Awaitable Awaitable resolved by the $thenable object.
*
* @throws \Error If the provided object does not have a then() method.
*/
function adapt($thenable): Awaitable {
$deferred = new Deferred;
$thenable->then([$deferred, 'resolve'], [$deferred, 'fail']);
return $deferred->getAwaitable();
}
/**
* Wraps the given callable $worker in a awaitable aware function that has the same number of arguments as $worker,
* but those arguments may be awaitables for the future argument value or just values. The returned function will
* return a awaitable for the return value of $worker and will never throw. The $worker function will not be called
* until each awaitable given as an argument is fulfilled. If any awaitable provided as an argument fails, the
* awaitable returned by the returned function will be failed for the same reason. The awaitable succeeds with
* the return value of $worker or failed if $worker throws.
*
* @param callable $worker
*
* @return callable
*/
function lift(callable $worker): callable {
/**
* @param mixed ...$args Awaitables or values.
*
* @return \Interop\Async\Awaitable
*/
return function (...$args) use ($worker): Awaitable {
foreach ($args as $key => $arg) {
if (!$arg instanceof Awaitable) {
$args[$key] = new Success($arg);
}
}
if (1 === \count($args)) {
return pipe($args[0], $worker);
}
return pipe(all($args), function (array $args) use ($worker) {
return $worker(...$args);
});
};
}
/**
* Returns a awaitable that is resolved when all awaitables are resolved. The returned awaitable will not fail.
* Returned awaitable succeeds with a two-item array delineating successful and failed awaitable results,
* with keys identical and corresponding to the original given array.
*
* This function is the same as some() with the notable exception that it will never fail even
* if all awaitables in the array resolve unsuccessfully.
*
* @param Awaitable[] $awaitables
*
* @return \Interop\Async\Awaitable
*
* @throws \Error If a non-Awaitable is in the array.
*/
function any(array $awaitables): Awaitable {
if (empty($awaitables)) {
return new Success([[], []]);
}
$deferred = new Deferred;
$pending = \count($awaitables);
$errors = [];
$values = [];
foreach ($awaitables as $key => $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \Error("Non-awaitable provided");
}
$awaitable->when(function ($error, $value) use (&$pending, &$errors, &$values, $key, $deferred) {
if ($error) {
$errors[$key] = $error;
} else {
$values[$key] = $value;
}
if (--$pending === 0) {
$deferred->resolve([$errors, $values]);
}
});
}
return $deferred->getAwaitable();
}
/**
* Returns a awaitable that succeeds when all awaitables succeed, and fails if any awaitable fails. Returned
* awaitable succeeds with an array of values used to succeed each contained awaitable, with keys corresponding to
* the array of awaitables.
*
* @param Awaitable[] $awaitables
*
* @return \Interop\Async\Awaitable
*
* @throws \Error If a non-Awaitable is in the array.
*/
function all(array $awaitables): Awaitable {
if (empty($awaitables)) {
return new Success([]);
}
$deferred = new Deferred;
$pending = \count($awaitables);
$resolved = false;
$values = [];
foreach ($awaitables as $key => $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \Error("Non-awaitable provided");
}
$awaitable->when(function ($exception, $value) use (&$values, &$pending, &$resolved, $key, $deferred) {
if ($resolved) {
return;
}
if ($exception) {
$resolved = true;
$deferred->fail($exception);
return;
}
$values[$key] = $value;
if (0 === --$pending) {
$deferred->resolve($values);
}
});
}
return $deferred->getAwaitable();
}
/**
* Returns a awaitable that succeeds when the first awaitable succeeds, and fails only if all awaitables fail.
*
* @param Awaitable[] $awaitables
*
* @return \Interop\Async\Awaitable
*
* @throws \Error If the array is empty or a non-Awaitable is in the array.
*/
function first(array $awaitables): Awaitable {
if (empty($awaitables)) {
throw new \Error("No awaitables provided");
}
$deferred = new Deferred;
$pending = \count($awaitables);
$resolved = false;
$exceptions = [];
foreach ($awaitables as $key => $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \Error("Non-awaitable provided");
}
$awaitable->when(function ($exception, $value) use (&$exceptions, &$pending, &$resolved, $key, $deferred) {
if ($resolved) {
return;
}
if (!$exception) {
$resolved = true;
$deferred->resolve($value);
return;
}
$exceptions[$key] = $exception;
if (0 === --$pending) {
$deferred->fail(new MultiReasonException($exceptions));
}
});
}
return $deferred->getAwaitable();
}
/**
* Resolves with a two-item array delineating successful and failed Awaitable results.
*
* The returned awaitable will only fail if ALL of the awaitables fail.
* @param Awaitable[] $awaitables
*
* @return \Interop\Async\Awaitable
*/
function some(array $awaitables): Awaitable {
if (empty($awaitables)) {
throw new \Error("No awaitables provided");
}
$pending = \count($awaitables);
$deferred = new Deferred;
$values = [];
$exceptions = [];
foreach ($awaitables as $key => $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \Error("Non-awaitable provided");
}
$awaitable->when(function ($exception, $value) use (&$values, &$exceptions, &$pending, $key, $deferred) {
if ($exception) {
$exceptions[$key] = $exception;
} else {
$values[$key] = $value;
}
if (0 === --$pending) {
if (empty($values)) {
$deferred->fail(new MultiReasonException($exceptions));
return;
}
$deferred->resolve([$exceptions, $values]);
}
});
}
return $deferred->getAwaitable();
}
/**
* Returns a awaitable that succeeds or fails when the first awaitable succeeds or fails.
*
* @param Awaitable[] $awaitables
*
* @return \Interop\Async\Awaitable
*
* @throws \Error If the array is empty or a non-Awaitable is in the array.
*/
function choose(array $awaitables): Awaitable {
if (empty($awaitables)) {
throw new \Error("No awaitables provided");
}
$deferred = new Deferred;
$resolved = false;
foreach ($awaitables as $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \Error("Non-awaitable provided");
}
$awaitable->when(function ($exception, $value) use (&$resolved, $deferred) {
if ($resolved) {
return;
}
$resolved = true;
if ($exception) {
$deferred->fail($exception);
return;
}
$deferred->resolve($value);
});
}
return $deferred->getAwaitable();
}
/**
* Maps the callback to each awaitable as it succeeds. Returns an array of awaitables resolved by the return
* callback value of the callback function. The callback may return awaitables or throw exceptions to fail
* awaitables in the array. If a awaitable in the passed array fails, the callback will not be called and the
* awaitable in the array fails for the same reason. Tip: Use all() or any() to determine when all
* awaitables in the array have been resolved.
*
* @param callable(mixed $value): mixed $callback
* @param Awaitable[] ...$awaitables
*
* @return \Interop\Async\Awaitable[] Array of awaitables resolved with the result of the mapped function.
*/
function map(callable $callback, array ...$awaitables): array {
$callback = lift($callback);
foreach ($awaitables as $awaitableSet) {
foreach ($awaitableSet as $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \Error("Non-awaitable provided");
}
}
}
return array_map($callback, ...$awaitables);
}
/**
* @param \Amp\Observable $observable
* @param callable(mixed $value): mixed $onNext
* @param callable(mixed $value): mixed|null $onComplete
*
* @return \Amp\Observable
*/
function each(Observable $observable, callable $onNext, callable $onComplete = null): Observable {
$postponed = new Postponed;
$pending = true;
$observable->subscribe(function ($value) use (&$pending, $postponed, $onNext) {
if ($pending) {
try {
return $postponed->emit($onNext($value));
} catch (\Throwable $exception) {
$pending = false;
$postponed->fail($exception);
}
}
return null;
});
$observable->when(function ($exception, $value) use (&$pending, $postponed, $onComplete) {
if (!$pending) {
return;
}
$pending = false;
if ($exception) {
$postponed->fail($exception);
return;
}
if ($onComplete === null) {
$postponed->resolve($value);
return;
}
try {
$postponed->resolve($onComplete($value));
} catch (\Throwable $exception) {
$postponed->fail($exception);
}
});
return $postponed->getObservable();
}
/**
* @param \Amp\Observable $observable
* @param callable(mixed $value): bool $filter
*
* @return \Amp\Observable
*/
function filter(Observable $observable, callable $filter): Observable {
$postponed = new Postponed;
$pending = true;
$observable->subscribe(function ($value) use (&$pending, $postponed, $filter) {
if ($pending) {
try {
if (!$filter($value)) {
return null;
}
return $postponed->emit($value);
} catch (\Throwable $exception) {
$pending = false;
$postponed->fail($exception);
}
}
return null;
});
$observable->when(function ($exception, $value) use (&$pending, $postponed) {
if (!$pending) {
return;
}
$pending = false;
if ($exception) {
$postponed->fail($exception);
return;
}
$postponed->resolve($value);
});
return $postponed->getObservable();
}
/**
* Creates an observable that emits values emitted from any observable in the array of observables.
*
* @param \Amp\Observable[] $observables
*
* @return \Amp\Observable
*/
function merge(array $observables): Observable {
$postponed = new Postponed;
foreach ($observables as $observable) {
if (!$observable instanceof Observable) {
throw new \Error("Non-observable provided");
}
$observable->subscribe([$postponed, 'emit']);
}
all($observables)->when(function ($exception, array $values) use ($postponed) {
if ($exception) {
$postponed->fail($exception);
return;
}
$postponed->resolve($values);
});
return $postponed->getObservable();
}
/**
* Creates an observable from the given array of awaitables, emitting the success value of each provided awaitable or
* failing if any awaitable fails.
*
* @param \Interop\Async\Awaitable[] $awaitables
*
* @return \Amp\Observable
*
* @throws \Error If a non-awaitable is provided.
*/
function stream(array $awaitables): Observable {
foreach ($awaitables as $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \Error("Non-awaitable provided");
}
}
return new Emitter(function (callable $emit) use ($awaitables) {
$emits = [];
foreach ($awaitables as $awaitable) {
$emits[] = $emit($awaitable);
}
yield all($emits);
});
}
/**
* Concatenates the given observables into a single observable, emitting values from a single observable at a time. The
* prior observable must complete before values are emitted from any subsequent observable. Observables are concatenated
* in the order given (iteration order of the array).
*
* @param array $observables
*
* @return \Amp\Observable
*/
function concat(array $observables): Observable {
foreach ($observables as $observable) {
if (!$observable instanceof Observable) {
throw new \Error("Non-observable provided");
}
}
$postponed = new Postponed;
$subscriptions = [];
$previous = [];
$awaitable = all($previous);
foreach ($observables as $observable) {
$subscriptions[] = $observable->subscribe(coroutine(function ($value) use ($postponed, $awaitable) {
try {
yield $awaitable;
} catch (\Throwable $exception) {
// Ignore exception in this context.
}
return yield $postponed->emit($value);
}));
$previous[] = $observable;
$awaitable = all($previous);
}
$awaitable->when(function ($exception, array $values) use ($postponed) {
if ($exception) {
$postponed->fail($exception);
return;
}
$postponed->resolve($values);
});
return $postponed->getObservable();
}
/**
* Returns an observable that emits a value every $interval milliseconds after (up to $count times). The value emitted
* is an integer of the number of times the observable emitted a value.
*
* @param int $interval Time interval between emitted values in milliseconds.
* @param int $count Number of values to emit. PHP_INT_MAX by default.
*
* @return \Amp\Observable
*
* @throws \Error If the number of times to emit is not a positive value.
*/
function interval(int $interval, int $count = PHP_INT_MAX): Observable {
if (0 >= $count) {
throw new \Error("The number of times to emit must be a positive value");
}
$postponed = new Postponed;
Loop::repeat($interval, function ($watcher) use (&$i, $postponed, $count) {
$postponed->emit(++$i);
if ($i === $count) {
Loop::cancel($watcher);
$postponed->resolve();
}
});
return $postponed->getObservable();
}
/**
* @param int $start
* @param int $end
* @param int $step
*
* @return \Amp\Observable
*
* @throws \Error If the step is 0 or not of the correct sign.
*/
function range(int $start, int $end, int $step = 1): Observable {
if (0 === $step) {
throw new \Error("Step must be a non-zero integer");
}
if ((($end - $start) ^ $step) < 0) {
throw new \Error("Step is not of the correct sign");
}
return new Emitter(function (callable $emit) use ($start, $end, $step) {
for ($i = $start; $i <= $end; $i += $step) {
yield $emit($i);
}
});
}