113 lines
3.2 KiB
PHP
113 lines
3.2 KiB
PHP
<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\Component\Filesystem;
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use Symfony\Component\Filesystem\Exception\IOException;
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/**
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* LockHandler class provides a simple abstraction to lock anything by means of
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* a file lock.
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*
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* A locked file is created based on the lock name when calling lock(). Other
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* lock handlers will not be able to lock the same name until it is released
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* (explicitly by calling release() or implicitly when the instance holding the
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* lock is destroyed).
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*
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* @author Grégoire Pineau <lyrixx@lyrixx.info>
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* @author Romain Neutron <imprec@gmail.com>
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* @author Nicolas Grekas <p@tchwork.com>
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*/
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class LockHandler
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{
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private $file;
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private $handle;
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/**
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* @param string $name The lock name
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* @param string|null $lockPath The directory to store the lock. Default values will use temporary directory
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*
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* @throws IOException If the lock directory could not be created or is not writable
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*/
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public function __construct($name, $lockPath = null)
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{
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$lockPath = $lockPath ?: sys_get_temp_dir();
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if (!is_dir($lockPath)) {
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$fs = new Filesystem();
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$fs->mkdir($lockPath);
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}
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if (!is_writable($lockPath)) {
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throw new IOException(sprintf('The directory "%s" is not writable.', $lockPath), 0, null, $lockPath);
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}
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$this->file = sprintf('%s/sf.%s.%s.lock', $lockPath, preg_replace('/[^a-z0-9\._-]+/i', '-', $name), hash('sha256', $name));
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}
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/**
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* Lock the resource.
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*
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* @param bool $blocking wait until the lock is released
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*
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* @return bool Returns true if the lock was acquired, false otherwise
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*
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* @throws IOException If the lock file could not be created or opened
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*/
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public function lock($blocking = false)
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{
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if ($this->handle) {
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return true;
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}
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// Silence error reporting
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set_error_handler(function() {});
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if (!$this->handle = fopen($this->file, 'r')) {
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if ($this->handle = fopen($this->file, 'x')) {
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chmod($this->file, 0444);
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} elseif (!$this->handle = fopen($this->file, 'r')) {
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usleep(100); // Give some time for chmod() to complete
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$this->handle = fopen($this->file, 'r');
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}
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}
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restore_error_handler();
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if (!$this->handle) {
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$error = error_get_last();
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throw new IOException($error['message'], 0, null, $this->file);
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}
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// On Windows, even if PHP doc says the contrary, LOCK_NB works, see
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// https://bugs.php.net/54129
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if (!flock($this->handle, LOCK_EX | ($blocking ? 0 : LOCK_NB))) {
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fclose($this->handle);
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$this->handle = null;
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return false;
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}
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return true;
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}
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/**
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* Release the resource.
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*/
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public function release()
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{
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if ($this->handle) {
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flock($this->handle, LOCK_UN | LOCK_NB);
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fclose($this->handle);
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$this->handle = null;
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}
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}
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}
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