scratch – Blame information for rev 115

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115 office 1 <?php
2  
3 /*
4 * This file is part of the Symfony package.
5 *
6 * (c) Fabien Potencier <fabien@symfony.com>
7 *
8 * For the full copyright and license information, please view the LICENSE
9 * file that was distributed with this source code.
10 */
11  
12 namespace Symfony\Component\Filesystem;
13  
14 use Symfony\Component\Filesystem\Exception\IOException;
15  
16 /**
17 * LockHandler class provides a simple abstraction to lock anything by means of
18 * a file lock.
19 *
20 * A locked file is created based on the lock name when calling lock(). Other
21 * lock handlers will not be able to lock the same name until it is released
22 * (explicitly by calling release() or implicitly when the instance holding the
23 * lock is destroyed).
24 *
25 * @author Grégoire Pineau <lyrixx@lyrixx.info>
26 * @author Romain Neutron <imprec@gmail.com>
27 * @author Nicolas Grekas <p@tchwork.com>
28 */
29 class LockHandler
30 {
31 private $file;
32 private $handle;
33  
34 /**
35 * @param string $name The lock name
36 * @param string|null $lockPath The directory to store the lock. Default values will use temporary directory
37 *
38 * @throws IOException If the lock directory could not be created or is not writable
39 */
40 public function __construct($name, $lockPath = null)
41 {
42 $lockPath = $lockPath ?: sys_get_temp_dir();
43  
44 if (!is_dir($lockPath)) {
45 $fs = new Filesystem();
46 $fs->mkdir($lockPath);
47 }
48  
49 if (!is_writable($lockPath)) {
50 throw new IOException(sprintf('The directory "%s" is not writable.', $lockPath), 0, null, $lockPath);
51 }
52  
53 $this->file = sprintf('%s/sf.%s.%s.lock', $lockPath, preg_replace('/[^a-z0-9\._-]+/i', '-', $name), hash('sha256', $name));
54 }
55  
56 /**
57 * Lock the resource.
58 *
59 * @param bool $blocking wait until the lock is released
60 *
61 * @return bool Returns true if the lock was acquired, false otherwise
62 *
63 * @throws IOException If the lock file could not be created or opened
64 */
65 public function lock($blocking = false)
66 {
67 if ($this->handle) {
68 return true;
69 }
70  
71 $error = null;
72  
73 // Silence error reporting
74 set_error_handler(function ($errno, $msg) use (&$error) {
75 $error = $msg;
76 });
77  
78 if (!$this->handle = fopen($this->file, 'r')) {
79 if ($this->handle = fopen($this->file, 'x')) {
80 chmod($this->file, 0444);
81 } elseif (!$this->handle = fopen($this->file, 'r')) {
82 usleep(100); // Give some time for chmod() to complete
83 $this->handle = fopen($this->file, 'r');
84 }
85 }
86 restore_error_handler();
87  
88 if (!$this->handle) {
89 throw new IOException($error, 0, null, $this->file);
90 }
91  
92 // On Windows, even if PHP doc says the contrary, LOCK_NB works, see
93 // https://bugs.php.net/54129
94 if (!flock($this->handle, LOCK_EX | ($blocking ? 0 : LOCK_NB))) {
95 fclose($this->handle);
96 $this->handle = null;
97  
98 return false;
99 }
100  
101 return true;
102 }
103  
104 /**
105 * Release the resource.
106 */
107 public function release()
108 {
109 if ($this->handle) {
110 flock($this->handle, LOCK_UN | LOCK_NB);
111 fclose($this->handle);
112 $this->handle = null;
113 }
114 }
115 }