SyncPromise::__construct() - Code Metrics - Inspection of "Upgrade PHPStan patch version" - simPod/graphql-php - Measure and Improve Code Quality continuously with Scrutinizer

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by Šimon

created 2020-02-28 19:48 UTC

SyncPromise::__construct() A

↳ Parent: SyncPromise

Complexity

Conditions	3
Paths	2

Size

Total Lines	10
Code Lines	7

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	5
CRAP Score	3

Importance

Changes

Metric	Value
eloc	7
dl	0
loc	10
ccs	5
cts	5
cp	1
rs	10
c	0
b	0
f	0
cc	3
nc	2
nop	1
crap	3

<?php

declare(strict_types=1);

namespace GraphQL\Executor\Promise\Adapter;

use Exception;
use GraphQL\Utils\Utils;
use SplQueue;
use Throwable;
use function is_object;
use function method_exists;

/**
 * Simplistic (yet full-featured) implementation of Promises A+ spec for regular PHP `sync` mode
 * (using queue to defer promises execution)
 *
 * Note:
 * Library users are not supposed to use SyncPromise class in their resolvers.
 * Instead they should use GraphQL\Deferred which enforces $executor callback in the constructor.
 *
 * Root SyncPromise without explicit $executor will never resolve (actually throw while trying).
 * The whole point of Deferred is to ensure it never happens and that any resolver creates
 * at least one $executor to start the promise chain.
 */
class SyncPromise
{
    const PENDING   = 'pending';
    const FULFILLED = 'fulfilled';
    const REJECTED  = 'rejected';

    /** @var SplQueue */
    public static $queue;

    /** @var string */
    public $state = self::PENDING;

    /** @var mixed */
    public $result;

    /**
     * Promises created in `then` method of this promise and awaiting for resolution of this promise
     *
     * @var mixed[][]
     */
    private $waiting = [];

    public static function runQueue() : void
    {
        $q = self::$queue;
        while ($q !== null && ! $q->isEmpty()) {
            $task = $q->dequeue();
            $task();
        }
    }

    /**
     * @param callable() : mixed $executor

     */
    public function __construct(?callable $executor = null)
    {
        if ($executor === null) {
            return;
        }
        self::getQueue()->enqueue(function () use ($executor) : void {
            try {
                $this->resolve($executor());
            } catch (Throwable $e) {
                $this->reject($e);
            }
        });
    }

    public function resolve($value) : self
    {
        switch ($this->state) {
            case self::PENDING:
                if ($value === $this) {
                    throw new Exception('Cannot resolve promise with self');
                }
                if (is_object($value) && method_exists($value, 'then')) {
                    $value->then(
                        function ($resolvedValue) : void {
                            $this->resolve($resolvedValue);
                        },
                        function ($reason) : void {
                            $this->reject($reason);
                        }
                    );

                    return $this;
                }

                $this->state  = self::FULFILLED;
                $this->result = $value;
                $this->enqueueWaitingPromises();
                break;
            case self::FULFILLED:
                if ($this->result !== $value) {
                    throw new Exception('Cannot change value of fulfilled promise');
                }
                break;
            case self::REJECTED:
                throw new Exception('Cannot resolve rejected promise');
        }

        return $this;
    }

    public function reject($reason) : self
    {
        if (! $reason instanceof Throwable) {
            throw new Exception('SyncPromise::reject() has to be called with an instance of \Throwable');
        }

        switch ($this->state) {
            case self::PENDING:
                $this->state  = self::REJECTED;
                $this->result = $reason;
                $this->enqueueWaitingPromises();
                break;
            case self::REJECTED:
                if ($reason !== $this->result) {
                    throw new Exception('Cannot change rejection reason');
                }
                break;
            case self::FULFILLED:
                throw new Exception('Cannot reject fulfilled promise');
        }

        return $this;
    }

    private function enqueueWaitingPromises() : void
    {
        Utils::invariant(
            $this->state !== self::PENDING,
            'Cannot enqueue derived promises when parent is still pending'
        );

        foreach ($this->waiting as $descriptor) {
            self::getQueue()->enqueue(function () use ($descriptor) : void {
                /** @var self $promise */
                [$promise, $onFulfilled, $onRejected] = $descriptor;

                if ($this->state === self::FULFILLED) {
                    try {
                        $promise->resolve($onFulfilled === null ? $this->result : $onFulfilled($this->result));
                    } catch (Throwable $e) {
                        $promise->reject($e);
                    }
                } elseif ($this->state === self::REJECTED) {
                    try {
                        if ($onRejected === null) {
                            $promise->reject($this->result);
                        } else {
                            $promise->resolve($onRejected($this->result));
                        }
                    } catch (Throwable $e) {
                        $promise->reject($e);
                    }
                }
            });
        }
        $this->waiting = [];
    }

    public static function getQueue() : SplQueue
    {
        return self::$queue ?: self::$queue = new SplQueue();
    }

    /**
     * @param callable(mixed) : mixed     $onFulfilled

     * @param callable(Throwable) : mixed $onRejected
     */
    public function then(?callable $onFulfilled = null, ?callable $onRejected = null) : self
    {
        if ($this->state === self::REJECTED && $onRejected === null) {
            return $this;
        }
        if ($this->state === self::FULFILLED && $onFulfilled === null) {
            return $this;
        }
        $tmp             = new self();
        $this->waiting[] = [$tmp, $onFulfilled, $onRejected];

        if ($this->state !== self::PENDING) {
            $this->enqueueWaitingPromises();
        }

        return $tmp;
    }

    /**
     * @param callable(Throwable) : mixed $onRejected

     */
    public function catch(callable $onRejected) : self
    {
        return $this->then(null, $onRejected);
    }
}


1		<?php
2
3		declare(strict_types=1);
4
5		namespace GraphQL\Executor\Promise\Adapter;
6
7		use Exception;
8		use GraphQL\Utils\Utils;
9		use SplQueue;
10		use Throwable;
11		use function is_object;
12		use function method_exists;
13
14		/**
15		* Simplistic (yet full-featured) implementation of Promises A+ spec for regular PHP `sync` mode
16		* (using queue to defer promises execution)
17		*
18		* Note:
19		* Library users are not supposed to use SyncPromise class in their resolvers.
20		* Instead they should use GraphQL\Deferred which enforces $executor callback in the constructor.
21		*
22		* Root SyncPromise without explicit $executor will never resolve (actually throw while trying).
23		* The whole point of Deferred is to ensure it never happens and that any resolver creates
24		* at least one $executor to start the promise chain.
25		*/
26		class SyncPromise
27		{
28		const PENDING = 'pending';
29		const FULFILLED = 'fulfilled';
30		const REJECTED = 'rejected';
31
32		/** @var SplQueue */
33		public static $queue;
34
35		/** @var string */
36		public $state = self::PENDING;
37
38		/** @var mixed */
39		public $result;
40
41	82	/**
42		* Promises created in `then` method of this promise and awaiting for resolution of this promise
43	82	*
44	82	* @var mixed[][]
45	82	*/
46	82	private $waiting = [];
47
48	82	public static function runQueue() : void
49		{
50	279	$q = self::$queue;
51		while ($q !== null && ! $q->isEmpty()) {
52	279	$task = $q->dequeue();
53	279	$task();
54	274	}
55	1	}
56
57	274	/**
58	25	* @param callable() : mixed $executor
		0 ignored issues – show Documentation Bug introduced 2020-02-28 19:51 UTC by Report Bug Copy Issue Report The doc comment `: mixed` at position `0` could not be parsed: Unknown type name ':' at position 0 in : mixed. Loading history...
59		*/
60	14	public function __construct(?callable $executor = null)
61	25	{
62		if ($executor === null) {
63	13	return;
64	25	}
65		self::getQueue()->enqueue(function () use ($executor) : void {
66		try {
67	25	$this->resolve($executor());
68		} catch (Throwable $e) {
69		$this->reject($e);
70	274	}
71	274	});
72	274	}
73	274
74	15	public function resolve($value) : self
75	5	{
76	5	switch ($this->state) {
77		case self::PENDING:
78		if ($value === $this) {
79	10	throw new Exception('Cannot resolve promise with self');
80	10	}
81		if (is_object($value) && method_exists($value, 'then')) {
82		$value->then(
83	274	function ($resolvedValue) : void {
84		$this->resolve($resolvedValue);
85		},
86	49	function ($reason) : void {
87		$this->reject($reason);
88	49	}
89	1	);
90
91		return $this;
92	49	}
93	49
94	44	$this->state = self::FULFILLED;
95	44	$this->result = $value;
96	44	$this->enqueueWaitingPromises();
97	44	break;
98	15	case self::FULFILLED:
99	10	if ($this->result !== $value) {
100	10	throw new Exception('Cannot change value of fulfilled promise');
101		}
102		break;
103	5	case self::REJECTED:
104	5	throw new Exception('Cannot resolve rejected promise');
105		}
106
107	44	return $this;
108		}
109
110	284	public function reject($reason) : self
111		{
112	284	if (! $reason instanceof Throwable) {
113	284	throw new Exception('SyncPromise::reject() has to be called with an instance of \Throwable');
114	284	}
115
116		switch ($this->state) {
117	284	case self::PENDING:
118		$this->state = self::REJECTED;
119		$this->result = $reason;
120	82	$this->enqueueWaitingPromises();
121		break;
122	82	case self::REJECTED:
123		if ($reason !== $this->result) {
124	78	throw new Exception('Cannot change rejection reason');
125	14	}
126	78	break;
127		case self::FULFILLED:
128	34	throw new Exception('Cannot reject fulfilled promise');
129		}
130	34
131	23	return $this;
132		}
133	34
134		private function enqueueWaitingPromises() : void
135	14	{
136	14	Utils::invariant(
137		$this->state !== self::PENDING,
138		'Cannot enqueue derived promises when parent is still pending'
139	82	);
140
141	284	foreach ($this->waiting as $descriptor) {
142	284	self::getQueue()->enqueue(function () use ($descriptor) : void {
143		/** @var self $promise */
144	258	[$promise, $onFulfilled, $onRejected] = $descriptor;
145
146	258	if ($this->state === self::FULFILLED) {
147		try {
148		$promise->resolve($onFulfilled === null ? $this->result : $onFulfilled($this->result));
149	83	} catch (Throwable $e) {
150		$promise->reject($e);
151	83	}
152	5	} elseif ($this->state === self::REJECTED) {
153		try {
154	83	if ($onRejected === null) {
155	5	$promise->reject($this->result);
156		} else {
157	83	$promise->resolve($onRejected($this->result));
158	83	}
159		} catch (Throwable $e) {
160	83	$promise->reject($e);
161	57	}
162		}
163		});
164	83	}
165		$this->waiting = [];
166		}
167
168		public static function getQueue() : SplQueue
169		{
170		return self::$queue ?: self::$queue = new SplQueue();
171		}
172
173		/**
174		* @param callable(mixed) : mixed $onFulfilled
		0 ignored issues – show Documentation Bug introduced 2020-02-28 19:51 UTC by Report Bug Copy Issue Report The doc comment `: mixed` at position `0` could not be parsed: Unknown type name ':' at position 0 in : mixed. Loading history...
175		* @param callable(Throwable) : mixed $onRejected
176		*/
177		public function then(?callable $onFulfilled = null, ?callable $onRejected = null) : self
178		{
179		if ($this->state === self::REJECTED && $onRejected === null) {
180		return $this;
181		}
182		if ($this->state === self::FULFILLED && $onFulfilled === null) {
183		return $this;
184		}
185		$tmp = new self();
186		$this->waiting[] = [$tmp, $onFulfilled, $onRejected];
187
188		if ($this->state !== self::PENDING) {
189		$this->enqueueWaitingPromises();
190		}
191
192		return $tmp;
193		}
194
195		/**
196		* @param callable(Throwable) : mixed $onRejected
		0 ignored issues – show Documentation Bug introduced 2020-02-28 19:51 UTC by Report Bug Copy Issue Report The doc comment `: mixed` at position `0` could not be parsed: Unknown type name ':' at position 0 in : mixed. Loading history...
197		*/
198		public function catch(callable $onRejected) : self
199		{
200		return $this->then(null, $onRejected);
201		}
202		}
203

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SyncPromise::__construct() A

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