Add upstream

wp-content/plugins/updraftplus/includes/Google/Cache/File.php

@@ -0,0 +1,206 @@
+<?php
+/*
+ * Copyright 2008 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+if (!class_exists('Google_Client')) {
+  require_once dirname(__FILE__) . '/../autoload.php';
+}
+
+/*
+ * This class implements a basic on disk storage. While that does
+ * work quite well it's not the most elegant and scalable solution.
+ * It will also get you into a heap of trouble when you try to run
+ * this in a clustered environment.
+ *
+ * @author Chris Chabot <chabotc@google.com>
+ */
+class Google_Cache_File extends Google_Cache_Abstract
+{
+  const MAX_LOCK_RETRIES = 10;
+  private $path;
+  private $fh;
+
+  /**
+   * @var Google_Client the current client
+   */
+  private $client;
+
+  public function __construct(Google_Client $client)
+  {
+    $this->client = $client;
+    $this->path = $this->client->getClassConfig($this, 'directory');
+  }
+
+  public function get($key, $expiration = false)
+  {
+    $storageFile = $this->getCacheFile($key);
+    $data = false;
+
+    if (!file_exists($storageFile)) {
+      $this->client->getLogger()->debug(
+          'File cache miss',
+          array('key' => $key, 'file' => $storageFile)
+      );
+      return false;
+    }
+
+    if ($expiration) {
+      $mtime = filemtime($storageFile);
+      if ((time() - $mtime) >= $expiration) {
+        $this->client->getLogger()->debug(
+            'File cache miss (expired)',
+            array('key' => $key, 'file' => $storageFile)
+        );
+        $this->delete($key);
+        return false;
+      }
+    }
+
+    if ($this->acquireReadLock($storageFile)) {
+      if (filesize($storageFile) > 0) {
+        $data = fread($this->fh, filesize($storageFile));
+        $data =  unserialize($data);
+      } else {
+        $this->client->getLogger()->debug(
+            'Cache file was empty',
+            array('file' => $storageFile)
+        );
+      }
+      $this->unlock($storageFile);
+    }
+
+    $this->client->getLogger()->debug(
+        'File cache hit',
+        array('key' => $key, 'file' => $storageFile, 'var' => $data)
+    );
+
+    return $data;
+  }
+
+  public function set($key, $value)
+  {
+    $storageFile = $this->getWriteableCacheFile($key);
+    if ($this->acquireWriteLock($storageFile)) {
+      // We serialize the whole request object, since we don't only want the
+      // responseContent but also the postBody used, headers, size, etc.
+      $data = serialize($value);
+      $result = fwrite($this->fh, $data);
+      $this->unlock($storageFile);
+
+      $this->client->getLogger()->debug(
+          'File cache set',
+          array('key' => $key, 'file' => $storageFile, 'var' => $value)
+      );
+    } else {
+      $this->client->getLogger()->notice(
+          'File cache set failed',
+          array('key' => $key, 'file' => $storageFile)
+      );
+    }
+  }
+
+  public function delete($key)
+  {
+    $file = $this->getCacheFile($key);
+    if (file_exists($file) && !unlink($file)) {
+      $this->client->getLogger()->error(
+          'File cache delete failed',
+          array('key' => $key, 'file' => $file)
+      );
+      throw new Google_Cache_Exception("Cache file could not be deleted");
+    }
+
+    $this->client->getLogger()->debug(
+        'File cache delete',
+        array('key' => $key, 'file' => $file)
+    );
+  }
+
+  private function getWriteableCacheFile($file)
+  {
+    return $this->getCacheFile($file, true);
+  }
+
+  private function getCacheFile($file, $forWrite = false)
+  {
+    return $this->getCacheDir($file, $forWrite) . '/' . md5($file);
+  }
+
+  private function getCacheDir($file, $forWrite)
+  {
+    // use the first 2 characters of the hash as a directory prefix
+    // this should prevent slowdowns due to huge directory listings
+    // and thus give some basic amount of scalability
+    $storageDir = $this->path . '/' . substr(md5($file), 0, 2);
+    if ($forWrite && ! is_dir($storageDir)) {
+      if (! mkdir($storageDir, 0755, true)) {
+        $this->client->getLogger()->error(
+            'File cache creation failed',
+            array('dir' => $storageDir)
+        );
+        throw new Google_Cache_Exception("Could not create storage directory: $storageDir");
+      }
+    }
+    return $storageDir;
+  }
+
+  private function acquireReadLock($storageFile)
+  {
+    return $this->acquireLock(LOCK_SH, $storageFile);
+  }
+
+  private function acquireWriteLock($storageFile)
+  {
+    $rc = $this->acquireLock(LOCK_EX, $storageFile);
+    if (!$rc) {
+      $this->client->getLogger()->notice(
+          'File cache write lock failed',
+          array('file' => $storageFile)
+      );
+      $this->delete($storageFile);
+    }
+    return $rc;
+  }
+
+  private function acquireLock($type, $storageFile)
+  {
+    $mode = $type == LOCK_EX ? "w" : "r";
+    $this->fh = fopen($storageFile, $mode);
+    if (!$this->fh) {
+      $this->client->getLogger()->error(
+          'Failed to open file during lock acquisition',
+          array('file' => $storageFile)
+      );
+      return false;
+    }
+    $count = 0;
+    while (!flock($this->fh, $type | LOCK_NB)) {
+      // Sleep for 10ms.
+      usleep(10000);
+      if (++$count < self::MAX_LOCK_RETRIES) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  public function unlock($storageFile)
+  {
+    if ($this->fh) {
+      flock($this->fh, LOCK_UN);
+    }
+  }
+}