File data/src/Type/LocalObjectType.php

1:	<?php
2:
3:	declare(strict_types=1);
4:
5:	namespace Atk4\Data\Type;
6:
7:	use Atk4\Data\Exception;
8:	use Doctrine\DBAL\Platforms\AbstractPlatform;
9:	use Doctrine\DBAL\Types as DbalTypes;
10:
11:	/**
12:	* Type that allows to weakly reference a local PHP object using a scalar string
13:	* and get the original object instance back using the string.
14:	*
15:	* The local object is never serialized.
16:	*
17:	* An exception is thrown when getting an object from a string back and the original
18:	* object instance has been destroyed/released.
19:	*/
20:	class LocalObjectType extends DbalTypes\Type
21:	{
22:	private ?string $instanceUid = null;
23:
24:	private int $localUidCounter;
25:
26:	/** @var \WeakMap<object, LocalObjectHandle> */
27:	private \WeakMap $handles;
28:	/** @var array<int, \WeakReference<LocalObjectHandle>> */
29:	private array $handlesIndex;
30:
31:	private function __clone()
32:	{
33:	// prevent cloning
34:	}
35:
36:	protected function init(): void
37:	{
38:	$this->instanceUid = hash('sha256', microtime(true) . random_bytes(64));
39:	$this->localUidCounter = 0;
40:	$this->handles = new \WeakMap();
41:	$this->handlesIndex = [];
42:	}
43:
44:	#[\Override]
45:	public function getName(): string
46:	{
47:	return Types::LOCAL_OBJECT;
48:	}
49:
50:	#[\Override]
51:	public function getSQLDeclaration(array $fieldDeclaration, AbstractPlatform $platform): string
52:	{
53:	return DbalTypes\Type::getType(DbalTypes\Types::STRING)->getSQLDeclaration($fieldDeclaration, $platform);
54:	}
55:
56:	#[\Override]
57:	public function convertToDatabaseValue($value, AbstractPlatform $platform): ?string
58:	{
59:	if ($value === null) {
60:	return null;
61:	}
62:
63:	if ($this->instanceUid === null) {
64:	$this->init();
65:	}
66:
67:	$handle = $this->handles->offsetExists($value)
68:	? $this->handles->offsetGet($value)
69:	: null;
70:
71:	if ($handle === null) {
72:	$handle = new LocalObjectHandle(++$this->localUidCounter, $value, function (LocalObjectHandle $handle): void {
73:	unset($this->handlesIndex[$handle->getLocalUid()]);
74:	});
75:	$this->handles->offsetSet($value, $handle);
76:	$this->handlesIndex[$handle->getLocalUid()] = \WeakReference::create($handle);
77:	}
78:
79:	$className = get_debug_type($value);
80:	if (strlen($className) > 160) { // keep result below 255 bytes
81:	$className = mb_strcut($className, 0, 80)
82:	. '...'
83:	. mb_strcut(substr($className, strlen(mb_strcut($className, 0, 80))), -80);
84:	}
85:
86:	return $className . '-' . $this->instanceUid . '-' . $handle->getLocalUid();
87:	}
88:
89:	#[\Override]
90:	public function convertToPHPValue($value, AbstractPlatform $platform): ?object
91:	{
92:	if ($value === null \|\| trim($value) === '') {
93:	return null;
94:	}
95:
96:	$valueExploded = explode('-', $value, 3);
97:	if (count($valueExploded) !== 3
98:	\|\| $valueExploded[1] !== $this->instanceUid
99:	\|\| $valueExploded[2] !== (string) (int) $valueExploded[2]
100:	) {
101:	throw new Exception('Local object does not match the DBAL type instance');
102:	}
103:	$handle = $this->handlesIndex[(int) $valueExploded[2]] ?? null;
104:	if ($handle !== null) {
105:	$handle = $handle->get();
106:	}
107:	$res = $handle !== null ? $handle->getValue() : null;
108:	if ($res === null) {
109:	throw new Exception('Local object does no longer exist');
110:	}
111:
112:	return $res;
113:	}
114:
115:	#[\Override]
116:	public function requiresSQLCommentHint(AbstractPlatform $platform): bool
117:	{
118:	return true;
119:	}
120:	}
121:

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