Promise::then() - Code Metrics - joenilson/residentes - Measure and Improve Code Quality continuously with Scrutinizer

Promise::then() A
last analyzed 2024-04-17 04:56 UTC

↳ Parent: Promise

Complexity

Conditions	5
Paths	5

Size

Total Lines	22
Code Lines	11

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	1	Features	0

Metric	Value
eloc	11
c	1
b	1
f	0
dl	0
loc	22
rs	9.6111
cc	5
nc	5
nop	2

<?php

namespace GuzzleHttp\Promise;

/**
 * Promises/A+ implementation that avoids recursion when possible.
 *
 * @link https://promisesaplus.com/
 */
class Promise implements PromiseInterface
{
    private $state = self::PENDING;
    private $result;
    private $cancelFn;
    private $waitFn;
    private $waitList;
    private $handlers = [];

    /**
     * @param callable $waitFn   Fn that when invoked resolves the promise.
     * @param callable $cancelFn Fn that when invoked cancels the promise.
     */
    public function __construct(
        callable $waitFn = null,
        callable $cancelFn = null
    ) {
        $this->waitFn = $waitFn;
        $this->cancelFn = $cancelFn;
    }

    public function then(
        callable $onFulfilled = null,
        callable $onRejected = null
    ) {
        if ($this->state === self::PENDING) {
            $p = new Promise(null, [$this, 'cancel']);
            $this->handlers[] = [$p, $onFulfilled, $onRejected];
            $p->waitList = $this->waitList;
            $p->waitList[] = $this;
            return $p;
        }

        // Return a fulfilled promise and immediately invoke any callbacks.
        if ($this->state === self::FULFILLED) {
            $promise = Create::promiseFor($this->result);
            return $onFulfilled ? $promise->then($onFulfilled) : $promise;
        }

        // It's either cancelled or rejected, so return a rejected promise
        // and immediately invoke any callbacks.
        $rejection = Create::rejectionFor($this->result);
        return $onRejected ? $rejection->then(null, $onRejected) : $rejection;
    }

    public function otherwise(callable $onRejected)
    {
        return $this->then(null, $onRejected);
    }

    public function wait($unwrap = true)
    {
        $this->waitIfPending();

        if ($this->result instanceof PromiseInterface) {
            return $this->result->wait($unwrap);
        }
        if ($unwrap) {
            if ($this->state === self::FULFILLED) {
                return $this->result;
            }
            // It's rejected so "unwrap" and throw an exception.
            throw Create::exceptionFor($this->result);
        }
    }

    public function getState()
    {
        return $this->state;
    }

    public function cancel()
    {
        if ($this->state !== self::PENDING) {
            return;
        }

        $this->waitFn = $this->waitList = null;

        if ($this->cancelFn) {
            $fn = $this->cancelFn;
            $this->cancelFn = null;
            try {
                $fn();
            } catch (\Throwable $e) {
                $this->reject($e);
            } catch (\Exception $e) {
                $this->reject($e);
            }
        }

        // Reject the promise only if it wasn't rejected in a then callback.
        /** @psalm-suppress RedundantCondition */
        if ($this->state === self::PENDING) {
            $this->reject(new CancellationException('Promise has been cancelled'));
        }
    }

    public function resolve($value)
    {
        $this->settle(self::FULFILLED, $value);
    }

    public function reject($reason)
    {
        $this->settle(self::REJECTED, $reason);
    }

    private function settle($state, $value)
    {
        if ($this->state !== self::PENDING) {
            // Ignore calls with the same resolution.
            if ($state === $this->state && $value === $this->result) {
                return;
            }
            throw $this->state === $state
                ? new \LogicException("The promise is already {$state}.")
                : new \LogicException("Cannot change a {$this->state} promise to {$state}");
        }

        if ($value === $this) {
            throw new \LogicException('Cannot fulfill or reject a promise with itself');
        }

        // Clear out the state of the promise but stash the handlers.
        $this->state = $state;
        $this->result = $value;
        $handlers = $this->handlers;
        $this->handlers = null;
        $this->waitList = $this->waitFn = null;
        $this->cancelFn = null;

        if (!$handlers) {

            return;
        }

        // If the value was not a settled promise or a thenable, then resolve
        // it in the task queue using the correct ID.
        if (!is_object($value) || !method_exists($value, 'then')) {
            $id = $state === self::FULFILLED ? 1 : 2;
            // It's a success, so resolve the handlers in the queue.
            Utils::queue()->add(static function () use ($id, $value, $handlers) {
                foreach ($handlers as $handler) {
                    self::callHandler($id, $value, $handler);
                }
            });
        } elseif ($value instanceof Promise && Is::pending($value)) {
            // We can just merge our handlers onto the next promise.
            $value->handlers = array_merge($value->handlers, $handlers);
        } else {
            // Resolve the handlers when the forwarded promise is resolved.
            $value->then(
                static function ($value) use ($handlers) {
                    foreach ($handlers as $handler) {
                        self::callHandler(1, $value, $handler);
                    }
                },
                static function ($reason) use ($handlers) {
                    foreach ($handlers as $handler) {
                        self::callHandler(2, $reason, $handler);
                    }
                }
            );
        }
    }

    /**
     * Call a stack of handlers using a specific callback index and value.
     *
     * @param int   $index   1 (resolve) or 2 (reject).
     * @param mixed $value   Value to pass to the callback.
     * @param array $handler Array of handler data (promise and callbacks).
     */
    private static function callHandler($index, $value, array $handler)
    {
        /** @var PromiseInterface $promise */
        $promise = $handler[0];

        // The promise may have been cancelled or resolved before placing
        // this thunk in the queue.
        if (Is::settled($promise)) {
            return;
        }

        try {
            if (isset($handler[$index])) {
                /*
                 * If $f throws an exception, then $handler will be in the exception
                 * stack trace. Since $handler contains a reference to the callable
                 * itself we get a circular reference. We clear the $handler
                 * here to avoid that memory leak.
                 */
                $f = $handler[$index];
                unset($handler);
                $promise->resolve($f($value));
            } elseif ($index === 1) {
                // Forward resolution values as-is.
                $promise->resolve($value);
            } else {
                // Forward rejections down the chain.
                $promise->reject($value);
            }
        } catch (\Throwable $reason) {
            $promise->reject($reason);
        } catch (\Exception $reason) {
            $promise->reject($reason);
        }
    }

    private function waitIfPending()
    {
        if ($this->state !== self::PENDING) {
            return;
        } elseif ($this->waitFn) {
            $this->invokeWaitFn();
        } elseif ($this->waitList) {
            $this->invokeWaitList();
        } else {
            // If there's no wait function, then reject the promise.
            $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.');
        }

        Utils::queue()->run();

        /** @psalm-suppress RedundantCondition */
        if ($this->state === self::PENDING) {
            $this->reject('Invoking the wait callback did not resolve the promise');
        }
    }

    private function invokeWaitFn()
    {
        try {
            $wfn = $this->waitFn;
            $this->waitFn = null;
            $wfn(true);
        } catch (\Exception $reason) {
            if ($this->state === self::PENDING) {
                // The promise has not been resolved yet, so reject the promise
                // with the exception.
                $this->reject($reason);
            } else {
                // The promise was already resolved, so there's a problem in
                // the application.
                throw $reason;
            }
        }
    }

    private function invokeWaitList()
    {
        $waitList = $this->waitList;
        $this->waitList = null;

        foreach ($waitList as $result) {
            do {
                $result->waitIfPending();
                $result = $result->result;
            } while ($result instanceof Promise);

            if ($result instanceof PromiseInterface) {
                $result->wait(false);
            }
        }
    }
}


1			<?php
2
3			namespace GuzzleHttp\Promise;
4
5			/**
6			* Promises/A+ implementation that avoids recursion when possible.
7			*
8			* @link https://promisesaplus.com/
9			*/
10			class Promise implements PromiseInterface
11			{
12			private $state = self::PENDING;
13			private $result;
14			private $cancelFn;
15			private $waitFn;
16			private $waitList;
17			private $handlers = [];
18
19			/**
20			* @param callable $waitFn Fn that when invoked resolves the promise.
21			* @param callable $cancelFn Fn that when invoked cancels the promise.
22			*/
23			public function __construct(
24			callable $waitFn = null,
25			callable $cancelFn = null
26			) {
27			$this->waitFn = $waitFn;
28			$this->cancelFn = $cancelFn;
29			}
30
31			public function then(
32			callable $onFulfilled = null,
33			callable $onRejected = null
34			) {
35			if ($this->state === self::PENDING) {
36			$p = new Promise(null, [$this, 'cancel']);
37			$this->handlers[] = [$p, $onFulfilled, $onRejected];
38			$p->waitList = $this->waitList;
39			$p->waitList[] = $this;
40			return $p;
41			}
42
43			// Return a fulfilled promise and immediately invoke any callbacks.
44			if ($this->state === self::FULFILLED) {
45			$promise = Create::promiseFor($this->result);
46			return $onFulfilled ? $promise->then($onFulfilled) : $promise;
47			}
48
49			// It's either cancelled or rejected, so return a rejected promise
50			// and immediately invoke any callbacks.
51			$rejection = Create::rejectionFor($this->result);
52			return $onRejected ? $rejection->then(null, $onRejected) : $rejection;
53			}
54
55			public function otherwise(callable $onRejected)
56			{
57			return $this->then(null, $onRejected);
58			}
59
60			public function wait($unwrap = true)
61			{
62			$this->waitIfPending();
63
64			if ($this->result instanceof PromiseInterface) {
65			return $this->result->wait($unwrap);
66			}
67			if ($unwrap) {
68			if ($this->state === self::FULFILLED) {
69			return $this->result;
70			}
71			// It's rejected so "unwrap" and throw an exception.
72			throw Create::exceptionFor($this->result);
73			}
74			}
75
76			public function getState()
77			{
78			return $this->state;
79			}
80
81			public function cancel()
82			{
83			if ($this->state !== self::PENDING) {
84			return;
85			}
86
87			$this->waitFn = $this->waitList = null;
88
89			if ($this->cancelFn) {
90			$fn = $this->cancelFn;
91			$this->cancelFn = null;
92			try {
93			$fn();
94			} catch (\Throwable $e) {
95			$this->reject($e);
96			} catch (\Exception $e) {
97			$this->reject($e);
98			}
99			}
100
101			// Reject the promise only if it wasn't rejected in a then callback.
102			/** @psalm-suppress RedundantCondition */
103			if ($this->state === self::PENDING) {
104			$this->reject(new CancellationException('Promise has been cancelled'));
105			}
106			}
107
108			public function resolve($value)
109			{
110			$this->settle(self::FULFILLED, $value);
111			}
112
113			public function reject($reason)
114			{
115			$this->settle(self::REJECTED, $reason);
116			}
117
118			private function settle($state, $value)
119			{
120			if ($this->state !== self::PENDING) {
121			// Ignore calls with the same resolution.
122			if ($state === $this->state && $value === $this->result) {
123			return;
124			}
125			throw $this->state === $state
126			? new \LogicException("The promise is already {$state}.")
127			: new \LogicException("Cannot change a {$this->state} promise to {$state}");
128			}
129
130			if ($value === $this) {
131			throw new \LogicException('Cannot fulfill or reject a promise with itself');
132			}
133
134			// Clear out the state of the promise but stash the handlers.
135			$this->state = $state;
136			$this->result = $value;
137			$handlers = $this->handlers;
138			$this->handlers = null;
139			$this->waitList = $this->waitFn = null;
140			$this->cancelFn = null;
141
142			if (!$handlers) {
			0 ignored issues – show Bug Best Practice introduced 2022-07-31 03:48 UTC by Report Bug Copy Issue Report The expression `$handlers` of type `array` is implicitly converted to a boolean; are you sure this is intended? If so, consider using `empty($expr)` instead to make it clear that you intend to check for an array without elements. This check marks implicit conversions of arrays to boolean values in a comparison. While in PHP an empty array is considered to be equal (but not identical) to false, this is not always apparent. Consider making the comparison explicit by using `empty(..)` or `! empty(...)` instead. Loading history...
143			return;
144			}
145
146			// If the value was not a settled promise or a thenable, then resolve
147			// it in the task queue using the correct ID.
148			if (!is_object($value) \|\| !method_exists($value, 'then')) {
149			$id = $state === self::FULFILLED ? 1 : 2;
150			// It's a success, so resolve the handlers in the queue.
151			Utils::queue()->add(static function () use ($id, $value, $handlers) {
152			foreach ($handlers as $handler) {
153			self::callHandler($id, $value, $handler);
154			}
155			});
156			} elseif ($value instanceof Promise && Is::pending($value)) {
157			// We can just merge our handlers onto the next promise.
158			$value->handlers = array_merge($value->handlers, $handlers);
159			} else {
160			// Resolve the handlers when the forwarded promise is resolved.
161			$value->then(
162			static function ($value) use ($handlers) {
163			foreach ($handlers as $handler) {
164			self::callHandler(1, $value, $handler);
165			}
166			},
167			static function ($reason) use ($handlers) {
168			foreach ($handlers as $handler) {
169			self::callHandler(2, $reason, $handler);
170			}
171			}
172			);
173			}
174			}
175
176			/**
177			* Call a stack of handlers using a specific callback index and value.
178			*
179			* @param int $index 1 (resolve) or 2 (reject).
180			* @param mixed $value Value to pass to the callback.
181			* @param array $handler Array of handler data (promise and callbacks).
182			*/
183			private static function callHandler($index, $value, array $handler)
184			{
185			/** @var PromiseInterface $promise */
186			$promise = $handler[0];
187
188			// The promise may have been cancelled or resolved before placing
189			// this thunk in the queue.
190			if (Is::settled($promise)) {
191			return;
192			}
193
194			try {
195			if (isset($handler[$index])) {
196			/*
197			* If $f throws an exception, then $handler will be in the exception
198			* stack trace. Since $handler contains a reference to the callable
199			* itself we get a circular reference. We clear the $handler
200			* here to avoid that memory leak.
201			*/
202			$f = $handler[$index];
203			unset($handler);
204			$promise->resolve($f($value));
205			} elseif ($index === 1) {
206			// Forward resolution values as-is.
207			$promise->resolve($value);
208			} else {
209			// Forward rejections down the chain.
210			$promise->reject($value);
211			}
212			} catch (\Throwable $reason) {
213			$promise->reject($reason);
214			} catch (\Exception $reason) {
215			$promise->reject($reason);
216			}
217			}
218
219			private function waitIfPending()
220			{
221			if ($this->state !== self::PENDING) {
222			return;
223			} elseif ($this->waitFn) {
224			$this->invokeWaitFn();
225			} elseif ($this->waitList) {
226			$this->invokeWaitList();
227			} else {
228			// If there's no wait function, then reject the promise.
229			$this->reject('Cannot wait on a promise that has '
230			. 'no internal wait function. You must provide a wait '
231			. 'function when constructing the promise to be able to '
232			. 'wait on a promise.');
233			}
234
235			Utils::queue()->run();
236
237			/** @psalm-suppress RedundantCondition */
238			if ($this->state === self::PENDING) {
239			$this->reject('Invoking the wait callback did not resolve the promise');
240			}
241			}
242
243			private function invokeWaitFn()
244			{
245			try {
246			$wfn = $this->waitFn;
247			$this->waitFn = null;
248			$wfn(true);
249			} catch (\Exception $reason) {
250			if ($this->state === self::PENDING) {
251			// The promise has not been resolved yet, so reject the promise
252			// with the exception.
253			$this->reject($reason);
254			} else {
255			// The promise was already resolved, so there's a problem in
256			// the application.
257			throw $reason;
258			}
259			}
260			}
261
262			private function invokeWaitList()
263			{
264			$waitList = $this->waitList;
265			$this->waitList = null;
266
267			foreach ($waitList as $result) {
268			do {
269			$result->waitIfPending();
270			$result = $result->result;
271			} while ($result instanceof Promise);
272
273			if ($result instanceof PromiseInterface) {
274			$result->wait(false);
275			}
276			}
277			}
278			}
279

joenilson / residentes

Promise::then() A last analyzed 2024-04-17 04:56 UTC

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Promise::then() A
last analyzed 2024-04-17 04:56 UTC