ProcessLock.php — WP STAGING – WordPress Backups, Restore, Migration & Clone 4.11.0

wp-staging / Framework / Job / ProcessLock.php

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ProcessLock.php

230 lines

1	<?php
2
3	namespace WPStaging\Framework\Job;
4
5	use RuntimeException;
6	use WPStaging\Core\WPStaging;
7	use WPStaging\Framework\Job\Exception\ProcessLockedException;
8	use WPStaging\Framework\Traits\ResourceTrait;
9
10	class ProcessLock
11	{
12	use ResourceTrait;
13
14	const LOCK_FILE_NAME = '.wpstg_process_locked';
15
16
17	private $lockFile;
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29
30	private static $handle = null;
31
32	public function __construct()
33	{
34	$this->lockFile = trailingslashit(WPStaging::getContentDir()) . self::LOCK_FILE_NAME;
35	}
36
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48
49	public function lockProcess()
50	{
51
52
53	if (self::$handle !== null) {
54	return;
55	}
56
57	$handle = $this->openLockFile();
58
59	if (!$this->acquireHandle($handle)) {
60	fclose($handle);
61
62	throw ProcessLockedException::processAlreadyLocked();
63	}
64
65	$this->writeLockedAt($handle);
66
67	self::$handle = $handle;
68	}
69
70
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73
74
75	public function unlockProcess()
76	{
77	$handle = self::$handle;
78
79	if ($handle === null) {
80	return;
81	}
82
83	self::$handle = null;
84
85
86
87
88	ftruncate($handle, 0);
89	flock($handle, LOCK_UN);
90	fclose($handle);
91	}
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106
107	public function checkProcessLocked($timeout = null)
108	{
109	if (self::$handle !== null) {
110	return;
111	}
112
113	$handle = $this->openLockFile();
114	$wouldBlock = 0;
115
116
117
118	if (flock($handle, LOCK_SH \| LOCK_NB, $wouldBlock)) {
119	flock($handle, LOCK_UN);
120	fclose($handle);
121
122	return;
123	}
124
125	fclose($handle);
126
127	if ($wouldBlock \|\| !$this->isLockRecordStale($timeout)) {
128	throw ProcessLockedException::processAlreadyLocked();
129	}
130	}
131
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135
136	private function acquireHandle($handle): bool
137	{
138	$wouldBlock = 0;
139
140	if (flock($handle, LOCK_EX \| LOCK_NB, $wouldBlock)) {
141	return true;
142	}
143
144
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146
147
148	if ($wouldBlock) {
149	return false;
150	}
151
152	return $this->isLockRecordStale();
153	}
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162
163	private function writeLockedAt($handle)
164	{
165	$lockedAt = (string)time();
166
167	ftruncate($handle, 0);
168	rewind($handle);
169
170	if (fwrite($handle, $lockedAt) !== strlen($lockedAt)) {
171	ftruncate($handle, 0);
172	}
173
174	fflush($handle);
175	}
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180
181	private function isLockRecordStale($timeout = null): bool
182	{
183	if (is_null($timeout)) {
184	$timeout = min(120, $this->getTimeLimit());
185	}
186
187	if (!file_exists($this->lockFile)) {
188	return true;
189	}
190
191	$lockedAt = file_get_contents($this->lockFile);
192
193
194
195	if (!is_numeric($lockedAt)) {
196	return true;
197	}
198
199	return (int)$lockedAt < time() - $timeout;
200	}
201
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205
206	private function openLockFile()
207	{
208
209
210	$error = '';
211	set_error_handler(function ($errno, $errstr) use (&$error) {
212	$error = $errstr;
213
214	return true;
215	});
216
217
218
219	$handle = fopen($this->lockFile, 'c+');
220
221	restore_error_handler();
222
223	if ($handle === false) {
224	throw new RuntimeException(sprintf('Could not open the process lock file %s. %s', $this->lockFile, $error));
225	}
226
227	return $handle;
228	}
229	}
230