<?php
declare(strict_types=1);
namespace Http\Client\Common;
use Http\Promise\Promise;
use Psr\Http\Client\ClientExceptionInterface;
use Psr\Http\Message\ResponseInterface;
/**
* A deferred allow to return a promise which has not been resolved yet.
*/
final class Deferred implements Promise
{
/**
* @var ResponseInterface|null
*/
private $value;
/**
* @var ClientExceptionInterface|null
*/
private $failure;
/**
* @var string
*/
private $state;
/**
* @var callable
*/
private $waitCallback;
/**
* @var callable[]
*/
private $onFulfilledCallbacks;
/**
* @var callable[]
*/
private $onRejectedCallbacks;
public function __construct(callable $waitCallback)
{
$this->waitCallback = $waitCallback;
$this->state = Promise::PENDING;
$this->onFulfilledCallbacks = [];
$this->onRejectedCallbacks = [];
}
public function then(?callable $onFulfilled = null, ?callable $onRejected = null): Promise
{
$deferred = new self($this->waitCallback);
$this->onFulfilledCallbacks[] = function (ResponseInterface $response) use ($onFulfilled, $deferred) {
try {
if (null !== $onFulfilled) {
$response = $onFulfilled($response);
}
$deferred->resolve($response);
} catch (ClientExceptionInterface $exception) {
$deferred->reject($exception);
}
};
$this->onRejectedCallbacks[] = function (ClientExceptionInterface $exception) use ($onRejected, $deferred) {
try {
if (null !== $onRejected) {
$response = $onRejected($exception);
$deferred->resolve($response);
return;
}
$deferred->reject($exception);
} catch (ClientExceptionInterface $newException) {
$deferred->reject($newException);
}
};
return $deferred;
}
public function getState(): string
{
return $this->state;
}
/**
* Resolve this deferred with a Response.
*/
public function resolve(ResponseInterface $response): void
{
if (Promise::PENDING !== $this->state) {
return;
}
$this->value = $response;
$this->state = Promise::FULFILLED;
foreach ($this->onFulfilledCallbacks as $onFulfilledCallback) {
$onFulfilledCallback($response);
}
}
/**
* Reject this deferred with an Exception.
*/
public function reject(ClientExceptionInterface $exception): void
{
if (Promise::PENDING !== $this->state) {
return;
}
$this->failure = $exception;
$this->state = Promise::REJECTED;
foreach ($this->onRejectedCallbacks as $onRejectedCallback) {
$onRejectedCallback($exception);
}
}
public function wait($unwrap = true)
{
if (Promise::PENDING === $this->state) {
$callback = $this->waitCallback;
$callback();
}
if (!$unwrap) {
return null;
}
if (Promise::FULFILLED === $this->state) {
return $this->value;
}
if (null === $this->failure) {
throw new \RuntimeException('Internal Error: Promise is not fulfilled but has no exception stored');
}
throw $this->failure;
}
}
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