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amp/lib/functions.php

696 lines
20 KiB
PHP

<?php
namespace Amp;
use Interop\Async\Awaitable;
use Interop\Async\Loop;
/**
* Returns a new function that when invoked runs the Generator returned by $worker as a coroutine.
*
* @param callable(mixed ...$args): \Generator $worker
*
* @return callable(mixed ...$args): \Amp\Coroutine
*/
function coroutine(callable $worker) {
return function (/* ...$args */) use ($worker) {
$generator = \call_user_func_array($worker, \func_get_args());
if (!$generator instanceof \Generator) {
throw new \LogicException("The callable did not return a Generator");
}
return new Coroutine($generator);
};
}
/**
* 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|\Exception 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 \LogicException("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) {
$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);
} catch (\Exception $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 $exception): mixed $functor
*
* @return \Interop\Async\Awaitable
*/
function capture(Awaitable $awaitable, $className, callable $functor) {
$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);
} catch (\Exception $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\Exception\TimeoutException.
*
* @param \Interop\Async\Awaitable $awaitable
* @param int $timeout Timeout in milliseconds.
*
* @return \Interop\Async\Awaitable
*/
function timeout(Awaitable $awaitable, $timeout) {
$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 */) {
$args = \array_slice(\func_get_args(), 1);
if (empty($args)) {
return new Internal\LazyAwaitable($promisor);
}
return new Internal\LazyAwaitable(function () use ($promisor, $args) {
return \call_user_func_array($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 $thenable object.
*
* @throws \InvalidArgumentException If the provided object does not have a then() method.
*/
function adapt($thenable) {
if (!\is_object($thenable) || !\method_exists($thenable, "then")) {
throw new \InvalidArgumentException("Must provide an object with a then() method");
}
$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 $worker) {
/**
* @param mixed ...$args Awaitables or values.
*
* @return \Interop\Async\Awaitable
*/
return function (/* ...$args */) use ($worker) {
$args = \func_get_args();
foreach ($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 \call_user_func_array($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 \InvalidArgumentException If a non-Awaitable is in the array.
*/
function any(array $awaitables) {
if (empty($awaitables)) {
return new Success([[], []]);
}
$deferred = new Deferred;
$pending = \count($awaitables);
$errors = [];
$values = [];
foreach ($awaitables as $key => $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \InvalidArgumentException("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 \InvalidArgumentException If a non-Awaitable is in the array.
*/
function all(array $awaitables) {
if (empty($awaitables)) {
return new Success([]);
}
$deferred = new Deferred;
$pending = \count($awaitables);
$resolved = false;
$values = [];
foreach ($awaitables as $key => $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \InvalidArgumentException("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 \InvalidArgumentException If the array is empty or a non-Awaitable is in the array.
*/
function first(array $awaitables) {
if (empty($awaitables)) {
throw new \InvalidArgumentException("No awaitables provided");
}
$deferred = new Deferred;
$pending = \count($awaitables);
$resolved = false;
$exceptions = [];
foreach ($awaitables as $key => $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \InvalidArgumentException("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();
}
/**
* Returns a awaitable that succeeds when $required number of awaitables succeed. The awaitable fails if $required
* number of awaitables can no longer succeed.
*
* @param Awaitable[] $awaitables
* @param int $required Number of awaitables that must succeed to succeed the returned awaitable.
*
* @return \Interop\Async\Awaitable
*/
function some(array $awaitables, $required) {
$required = (int) $required;
if (0 >= $required) {
return new Success([]);
}
$pending = \count($awaitables);
if ($required > $pending) {
throw new \InvalidArgumentException("Too few awaitables provided");
}
$deferred = new Deferred;
$resolved = false;
$values = [];
$exceptions = [];
foreach ($awaitables as $key => $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \InvalidArgumentException("Non-awaitable provided");
}
$awaitable->when(function ($exception, $value) use (
&$values, &$exceptions, &$pending, &$resolved, &$required, $key, $deferred
) {
if ($resolved) {
return;
}
if ($exception) {
$exceptions[$key] = $exception;
if ($required > --$pending) {
$resolved = true;
$deferred->fail(new MultiReasonException($exceptions));
}
return;
}
$values[$key] = $value;
--$pending;
if (0 === --$required) {
$resolved = true;
$deferred->resolve($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 \InvalidArgumentException If the array is empty or a non-Awaitable is in the array.
*/
function choose(array $awaitables) {
if (empty($awaitables)) {
throw new \InvalidArgumentException("No awaitables provided");
}
$deferred = new Deferred;
$resolved = false;
foreach ($awaitables as $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \InvalidArgumentException("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 */) {
$args = \func_get_args();
$count = \count($args);
$args[0] = lift($callback);
for ($i = 1; $i < $count; ++$i) {
foreach ($args[$i] as $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \InvalidArgumentException('Non-awaitable provided');
}
}
}
return \call_user_func_array("array_map", $args);
}
/**
* @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) {
return new Emitter(function (callable $emit) use ($observable, $onNext, $onComplete) {
$result = (yield $observable->subscribe(function ($value) use ($emit, $onNext) {
return $emit($onNext($value));
}));
if ($onComplete === null) {
yield Coroutine::result($result);
return;
}
yield Coroutine::result($onComplete($result));
});
}
/**
* @param \Amp\Observable $observable
* @param callable(mixed $value): bool $filter
*
* @return \Amp\Observable
*/
function filter(Observable $observable, callable $filter) {
return new Emitter(function (callable $emit) use ($observable, $filter) {
yield Coroutine::result(yield $observable->subscribe(function ($value) use ($emit, $filter) {
if (!$filter($value)) {
return null;
}
return $emit($value);
}));
});
}
/**
* Creates an observable that emits values emitted from any observable in the array of observables. Values in the
* array are passed through the from() function, so they may be observables, arrays of values to emit, awaitables,
* or any other value.
*
* @param \Amp\Observable[] $observables
*
* @return \Amp\Observable
*/
function merge(array $observables) {
foreach ($observables as $observable) {
if (!$observable instanceof Observable) {
throw new \InvalidArgumentException("Non-observable provided");
}
}
return new Emitter(function (callable $emit) use ($observables) {
$subscriptions = [];
foreach ($observables as $observable) {
$subscriptions[] = $observable->subscribe($emit);
}
try {
$result = (yield all($subscriptions));
} finally {
foreach ($subscriptions as $subscription) {
$subscription->unsubscribe();
}
}
yield Coroutine::result($result);
});
}
/**
* Creates an observable from the given array of observables, emitting the success value of each provided awaitable or
* failing if any awaitable fails.
*
* @param \Interop\Async\Awaitable[] $awaitables
*
* @return \Amp\Observable
*/
function stream(array $awaitables) {
$postponed = new Postponed;
if (empty($awaitables)) {
$postponed->complete();
return $postponed;
}
$pending = \count($awaitables);
$onResolved = function ($exception, $value) use (&$pending, $postponed) {
if ($pending <= 0) {
return;
}
if ($exception) {
$pending = 0;
$postponed->fail($exception);
return;
}
$postponed->emit($value);
if (--$pending === 0) {
$postponed->complete();
}
};
foreach ($awaitables as $awaitable) {
if (!$awaitable instanceof Awaitable) {
throw new \InvalidArgumentException("Non-awaitable provided");
}
$awaitable->when($onResolved);
}
return $postponed;
}
/**
* Returns an observable that emits a value every $interval milliseconds after the previous value has been consumed
* (up to $count times (or indefinitely if $count is 0). 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 $count Use 0 to emit values indefinitely.
*
* @return \Amp\Observable
*/
function interval($interval, $count = 0) {
$count = (int) $count;
if (0 > $count) {
throw new \InvalidArgumentException("The number of times to emit must be a non-negative 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 $step
*
* @return \Amp\Observable
*/
function range($start, $end, $step = 1) {
$start = (int) $start;
$end = (int) $end;
$step = (int) $step;
if (0 === $step) {
throw new \InvalidArgumentException("Step must be a non-zero integer");
}
if ((($end - $start) ^ $step) < 0) {
throw new \InvalidArgumentException("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);
}
});
}