wordpress-seo / vendor_prefixed / guzzlehttp / promises / src / Promise.php

Promise.php in Yoast SEO – Advanced SEO with real-time guidance and built-in AI 27.7, at vendor_prefixed/guzzlehttp/promises/src/Promise.php

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1	<?php
2
3	declare (strict_types=1);
4	namespace YoastSEO_Vendor\GuzzleHttp\Promise;
5
6	/**
7	* Promises/A+ implementation that avoids recursion when possible.
8	*
9	* @see https://promisesaplus.com/
10	*
11	* @final
12	*/
13	class Promise implements \YoastSEO_Vendor\GuzzleHttp\Promise\PromiseInterface
14	{
15	private $state = self::PENDING;
16	private $result;
17	private $cancelFn;
18	private $waitFn;
19	private $waitList;
20	private $handlers = [];
21	/**
22	* @param callable $waitFn Fn that when invoked resolves the promise.
23	* @param callable $cancelFn Fn that when invoked cancels the promise.
24	*/
25	public function __construct(?callable $waitFn = null, ?callable $cancelFn = null)
26	{
27	$this->waitFn = $waitFn;
28	$this->cancelFn = $cancelFn;
29	}
30	public function then(?callable $onFulfilled = null, ?callable $onRejected = null) : \YoastSEO_Vendor\GuzzleHttp\Promise\PromiseInterface
31	{
32	if ($this->state === self::PENDING) {
33	$p = new \YoastSEO_Vendor\GuzzleHttp\Promise\Promise(null, [$this, 'cancel']);
34	$this->handlers[] = [$p, $onFulfilled, $onRejected];
35	$p->waitList = $this->waitList;
36	$p->waitList[] = $this;
37	return $p;
38	}
39	// Return a fulfilled promise and immediately invoke any callbacks.
40	if ($this->state === self::FULFILLED) {
41	$promise = \YoastSEO_Vendor\GuzzleHttp\Promise\Create::promiseFor($this->result);
42	return $onFulfilled ? $promise->then($onFulfilled) : $promise;
43	}
44	// It's either cancelled or rejected, so return a rejected promise
45	// and immediately invoke any callbacks.
46	$rejection = \YoastSEO_Vendor\GuzzleHttp\Promise\Create::rejectionFor($this->result);
47	return $onRejected ? $rejection->then(null, $onRejected) : $rejection;
48	}
49	public function otherwise(callable $onRejected) : \YoastSEO_Vendor\GuzzleHttp\Promise\PromiseInterface
50	{
51	return $this->then(null, $onRejected);
52	}
53	public function wait(bool $unwrap = \true)
54	{
55	$this->waitIfPending();
56	if ($this->result instanceof \YoastSEO_Vendor\GuzzleHttp\Promise\PromiseInterface) {
57	return $this->result->wait($unwrap);
58	}
59	if ($unwrap) {
60	if ($this->state === self::FULFILLED) {
61	return $this->result;
62	}
63	// It's rejected so "unwrap" and throw an exception.
64	throw \YoastSEO_Vendor\GuzzleHttp\Promise\Create::exceptionFor($this->result);
65	}
66	}
67	public function getState() : string
68	{
69	return $this->state;
70	}
71	public function cancel() : void
72	{
73	if ($this->state !== self::PENDING) {
74	return;
75	}
76	$this->waitFn = $this->waitList = null;
77	if ($this->cancelFn) {
78	$fn = $this->cancelFn;
79	$this->cancelFn = null;
80	try {
81	$fn();
82	} catch (\Throwable $e) {
83	$this->reject($e);
84	}
85	}
86	// Reject the promise only if it wasn't rejected in a then callback.
87	/** @psalm-suppress RedundantCondition */
88	if ($this->state === self::PENDING) {
89	$this->reject(new \YoastSEO_Vendor\GuzzleHttp\Promise\CancellationException('Promise has been cancelled'));
90	}
91	}
92	public function resolve($value) : void
93	{
94	$this->settle(self::FULFILLED, $value);
95	}
96	public function reject($reason) : void
97	{
98	$this->settle(self::REJECTED, $reason);
99	}
100	private function settle(string $state, $value) : void
101	{
102	if ($this->state !== self::PENDING) {
103	// Ignore calls with the same resolution.
104	if ($state === $this->state && $value === $this->result) {
105	return;
106	}
107	throw $this->state === $state ? new \LogicException("The promise is already {$state}.") : new \LogicException("Cannot change a {$this->state} promise to {$state}");
108	}
109	if ($value === $this) {
110	throw new \LogicException('Cannot fulfill or reject a promise with itself');
111	}
112	// Clear out the state of the promise but stash the handlers.
113	$this->state = $state;
114	$this->result = $value;
115	$handlers = $this->handlers;
116	$this->handlers = null;
117	$this->waitList = $this->waitFn = null;
118	$this->cancelFn = null;
119	if (!$handlers) {
120	return;
121	}
122	// If the value was not a settled promise or a thenable, then resolve
123	// it in the task queue using the correct ID.
124	if (!\is_object($value) \|\| !\method_exists($value, 'then')) {
125	$id = $state === self::FULFILLED ? 1 : 2;
126	// It's a success, so resolve the handlers in the queue.
127	\YoastSEO_Vendor\GuzzleHttp\Promise\Utils::queue()->add(static function () use($id, $value, $handlers) : void {
128	foreach ($handlers as $handler) {
129	self::callHandler($id, $value, $handler);
130	}
131	});
132	} elseif ($value instanceof \YoastSEO_Vendor\GuzzleHttp\Promise\Promise && \YoastSEO_Vendor\GuzzleHttp\Promise\Is::pending($value)) {
133	// We can just merge our handlers onto the next promise.
134	$value->handlers = \array_merge($value->handlers, $handlers);
135	} else {
136	// Resolve the handlers when the forwarded promise is resolved.
137	$value->then(static function ($value) use($handlers) : void {
138	foreach ($handlers as $handler) {
139	self::callHandler(1, $value, $handler);
140	}
141	}, static function ($reason) use($handlers) : void {
142	foreach ($handlers as $handler) {
143	self::callHandler(2, $reason, $handler);
144	}
145	});
146	}
147	}
148	/**
149	* Call a stack of handlers using a specific callback index and value.
150	*
151	* @param int $index 1 (resolve) or 2 (reject).
152	* @param mixed $value Value to pass to the callback.
153	* @param array $handler Array of handler data (promise and callbacks).
154	*/
155	private static function callHandler(int $index, $value, array $handler) : void
156	{
157	/** @var PromiseInterface $promise */
158	$promise = $handler[0];
159	// The promise may have been cancelled or resolved before placing
160	// this thunk in the queue.
161	if (\YoastSEO_Vendor\GuzzleHttp\Promise\Is::settled($promise)) {
162	return;
163	}
164	try {
165	if (isset($handler[$index])) {
166	/*
167	* If $f throws an exception, then $handler will be in the exception
168	* stack trace. Since $handler contains a reference to the callable
169	* itself we get a circular reference. We clear the $handler
170	* here to avoid that memory leak.
171	*/
172	$f = $handler[$index];
173	unset($handler);
174	$promise->resolve($f($value));
175	} elseif ($index === 1) {
176	// Forward resolution values as-is.
177	$promise->resolve($value);
178	} else {
179	// Forward rejections down the chain.
180	$promise->reject($value);
181	}
182	} catch (\Throwable $reason) {
183	$promise->reject($reason);
184	}
185	}
186	private function waitIfPending() : void
187	{
188	if ($this->state !== self::PENDING) {
189	return;
190	} elseif ($this->waitFn) {
191	$this->invokeWaitFn();
192	} elseif ($this->waitList) {
193	$this->invokeWaitList();
194	} else {
195	// If there's no wait function, then reject the promise.
196	$this->reject('Cannot wait on a promise that has ' . 'no internal wait function. You must provide a wait ' . 'function when constructing the promise to be able to ' . 'wait on a promise.');
197	}
198	\YoastSEO_Vendor\GuzzleHttp\Promise\Utils::queue()->run();
199	/** @psalm-suppress RedundantCondition */
200	if ($this->state === self::PENDING) {
201	$this->reject('Invoking the wait callback did not resolve the promise');
202	}
203	}
204	private function invokeWaitFn() : void
205	{
206	try {
207	$wfn = $this->waitFn;
208	$this->waitFn = null;
209	$wfn(\true);
210	} catch (\Throwable $reason) {
211	if ($this->state === self::PENDING) {
212	// The promise has not been resolved yet, so reject the promise
213	// with the exception.
214	$this->reject($reason);
215	} else {
216	// The promise was already resolved, so there's a problem in
217	// the application.
218	throw $reason;
219	}
220	}
221	}
222	private function invokeWaitList() : void
223	{
224	$waitList = $this->waitList;
225	$this->waitList = null;
226	foreach ($waitList as $result) {
227	do {
228	$result->waitIfPending();
229	$result = $result->result;
230	} while ($result instanceof \YoastSEO_Vendor\GuzzleHttp\Promise\Promise);
231	if ($result instanceof \YoastSEO_Vendor\GuzzleHttp\Promise\PromiseInterface) {
232	$result->wait(\false);
233	}
234	}
235	}
236	}
237