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lib/influxdb-php/vendor/symfony/filesystem/LockHandler.php

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