<?php
namespace GuzzleHttp\Promise;
final class Utils
{
/**
* Get the global task queue used for promise resolution.
*
* This task queue MUST be run in an event loop in order for promises to be
* settled asynchronously. It will be automatically run when synchronously
* waiting on a promise.
*
* <code>
* while ($eventLoop->isRunning()) {
* GuzzleHttp\Promise\Utils::queue()->run();
* }
* </code>
*
* @param TaskQueueInterface $assign Optionally specify a new queue instance.
*
* @return TaskQueueInterface
*/
public static function queue(TaskQueueInterface $assign = null)
{
static $queue;
if ($assign) {
$queue = $assign;
} elseif (!$queue) {
$queue = new TaskQueue();
}
return $queue;
}
/**
* Adds a function to run in the task queue when it is next `run()` and
* returns a promise that is fulfilled or rejected with the result.
*
* @param callable $task Task function to run.
*
* @return PromiseInterface
*/
public static function task(callable $task)
{
$queue = self::queue();
$promise = new Promise([$queue, 'run']);
$queue->add(function () use ($task, $promise) {
try {
if (Is::pending($promise)) {
$promise->resolve($task());
}
} catch (\Throwable $e) {
$promise->reject($e);
} catch (\Exception $e) {
$promise->reject($e);
}
});
return $promise;
}
/**
* Synchronously waits on a promise to resolve and returns an inspection
* state array.
*
* Returns a state associative array containing a "state" key mapping to a
* valid promise state. If the state of the promise is "fulfilled", the
* array will contain a "value" key mapping to the fulfilled value of the
* promise. If the promise is rejected, the array will contain a "reason"
* key mapping to the rejection reason of the promise.
*
* @param PromiseInterface $promise Promise or value.
*
* @return array
*/
public static function inspect(PromiseInterface $promise)
{
try {
return [
'state' => PromiseInterface::FULFILLED,
'value' => $promise->wait()
];
} catch (RejectionException $e) {
return ['state' => PromiseInterface::REJECTED, 'reason' => $e->getReason()];
} catch (\Throwable $e) {
return ['state' => PromiseInterface::REJECTED, 'reason' => $e];
} catch (\Exception $e) {
return ['state' => PromiseInterface::REJECTED, 'reason' => $e];
}
}
/**
* Waits on all of the provided promises, but does not unwrap rejected
* promises as thrown exception.
*
* Returns an array of inspection state arrays.
*
* @see inspect for the inspection state array format.
*
* @param PromiseInterface[] $promises Traversable of promises to wait upon.
*
* @return array
*/
public static function inspectAll($promises)
{
$results = [];
foreach ($promises as $key => $promise) {
$results[$key] = inspect($promise);
}
return $results;
}
/**
* Waits on all of the provided promises and returns the fulfilled values.
*
* Returns an array that contains the value of each promise (in the same
* order the promises were provided). An exception is thrown if any of the
* promises are rejected.
*
* @param iterable<PromiseInterface> $promises Iterable of PromiseInterface objects to wait on.
*
* @return array
*
* @throws \Exception on error
* @throws \Throwable on error in PHP >=7
*/
public static function unwrap($promises)
{
$results = [];
foreach ($promises as $key => $promise) {
$results[$key] = $promise->wait();
}
return $results;
}
/**
* Given an array of promises, return a promise that is fulfilled when all
* the items in the array are fulfilled.
*
* The promise's fulfillment value is an array with fulfillment values at
* respective positions to the original array. If any promise in the array
* rejects, the returned promise is rejected with the rejection reason.
*
* @param mixed $promises Promises or values.
* @param bool $recursive If true, resolves new promises that might have been added to the stack during its own resolution.
*
* @return PromiseInterface
*/
public static function all($promises, $recursive = false)
{
$results = [];
$promise = Each::of(
$promises,
function ($value, $idx) use (&$results) {
$results[$idx] = $value;
},
function ($reason, $idx, Promise $aggregate) {
$aggregate->reject($reason);
}
)->then(function () use (&$results) {
ksort($results);
return $results;
});
if (true === $recursive) {
$promise = $promise->then(function ($results) use ($recursive, &$promises) {
foreach ($promises as $promise) {
if (Is::pending($promise)) {
return self::all($promises, $recursive);
}
}
return $results;
});
}
return $promise;
}
/**
* Initiate a competitive race between multiple promises or values (values
* will become immediately fulfilled promises).
*
* When count amount of promises have been fulfilled, the returned promise
* is fulfilled with an array that contains the fulfillment values of the
* winners in order of resolution.
*
* This promise is rejected with a {@see AggregateException} if the number
* of fulfilled promises is less than the desired $count.
*
* @param int $count Total number of promises.
* @param mixed $promises Promises or values.
*
* @return PromiseInterface
*/
public static function some($count, $promises)
{
$results = [];
$rejections = [];
return Each::of(
$promises,
function ($value, $idx, PromiseInterface $p) use (&$results, $count) {
if (Is::settled($p)) {
return;
}
$results[$idx] = $value;
if (count($results) >= $count) {
$p->resolve(null);
}
},
function ($reason) use (&$rejections) {
$rejections[] = $reason;
}
)->then(
function () use (&$results, &$rejections, $count) {
if (count($results) !== $count) {
throw new AggregateException(
'Not enough promises to fulfill count',
$rejections
);
}
ksort($results);
return array_values($results);
}
);
}
/**
* Like some(), with 1 as count. However, if the promise fulfills, the
* fulfillment value is not an array of 1 but the value directly.
*
* @param mixed $promises Promises or values.
*
* @return PromiseInterface
*/
public static function any($promises)
{
return self::some(1, $promises)->then(function ($values) {
return $values[0];
});
}
/**
* Returns a promise that is fulfilled when all of the provided promises have
* been fulfilled or rejected.
*
* The returned promise is fulfilled with an array of inspection state arrays.
*
* @see inspect for the inspection state array format.
*
* @param mixed $promises Promises or values.
*
* @return PromiseInterface
*/
public static function settle($promises)
{
$results = [];
return Each::of(
$promises,
function ($value, $idx) use (&$results) {
$results[$idx] = ['state' => PromiseInterface::FULFILLED, 'value' => $value];
},
function ($reason, $idx) use (&$results) {
$results[$idx] = ['state' => PromiseInterface::REJECTED, 'reason' => $reason];
}
)->then(function () use (&$results) {
ksort($results);
return $results;
});
}
}