authorizer / vendor / google-api-php-client / src / Google / Cache / File.php

File.php in Authorizer 2.9.0, at vendor/google-api-php-client/src/Google/Cache/File.php

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1	<?php
2	/*
3	* Copyright 2008 Google Inc.
4	*
5	* Licensed under the Apache License, Version 2.0 (the "License");
6	* you may not use this file except in compliance with the License.
7	* You may obtain a copy of the License at
8	*
9	* http://www.apache.org/licenses/LICENSE-2.0
10	*
11	* Unless required by applicable law or agreed to in writing, software
12	* distributed under the License is distributed on an "AS IS" BASIS,
13	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14	* See the License for the specific language governing permissions and
15	* limitations under the License.
16	*/
17
18	if (!class_exists('Google_Client')) {
19	require_once dirname(__FILE__) . '/../autoload.php';
20	}
21
22	/*
23	* This class implements a basic on disk storage. While that does
24	* work quite well it's not the most elegant and scalable solution.
25	* It will also get you into a heap of trouble when you try to run
26	* this in a clustered environment.
27	*
28	* @author Chris Chabot <chabotc@google.com>
29	*/
30	class Google_Cache_File extends Google_Cache_Abstract
31	{
32	const MAX_LOCK_RETRIES = 10;
33	private $path;
34	private $fh;
35
36	/**
37	* @var Google_Client the current client
38	*/
39	private $client;
40
41	public function __construct(Google_Client $client)
42	{
43	$this->client = $client;
44	$this->path = $this->client->getClassConfig($this, 'directory');
45	}
46
47	public function get($key, $expiration = false)
48	{
49	$storageFile = $this->getCacheFile($key);
50	$data = false;
51
52	if (!file_exists($storageFile)) {
53	$this->client->getLogger()->debug(
54	'File cache miss',
55	array('key' => $key, 'file' => $storageFile)
56	);
57	return false;
58	}
59
60	if ($expiration) {
61	$mtime = filemtime($storageFile);
62	if ((time() - $mtime) >= $expiration) {
63	$this->client->getLogger()->debug(
64	'File cache miss (expired)',
65	array('key' => $key, 'file' => $storageFile)
66	);
67	$this->delete($key);
68	return false;
69	}
70	}
71
72	if ($this->acquireReadLock($storageFile)) {
73	if (filesize($storageFile) > 0) {
74	$data = fread($this->fh, filesize($storageFile));
75	$data = unserialize($data);
76	} else {
77	$this->client->getLogger()->debug(
78	'Cache file was empty',
79	array('file' => $storageFile)
80	);
81	}
82	$this->unlock($storageFile);
83	}
84
85	$this->client->getLogger()->debug(
86	'File cache hit',
87	array('key' => $key, 'file' => $storageFile, 'var' => $data)
88	);
89
90	return $data;
91	}
92
93	public function set($key, $value)
94	{
95	$storageFile = $this->getWriteableCacheFile($key);
96	if ($this->acquireWriteLock($storageFile)) {
97	// We serialize the whole request object, since we don't only want the
98	// responseContent but also the postBody used, headers, size, etc.
99	$data = serialize($value);
100	$result = fwrite($this->fh, $data);
101	$this->unlock($storageFile);
102
103	$this->client->getLogger()->debug(
104	'File cache set',
105	array('key' => $key, 'file' => $storageFile, 'var' => $value)
106	);
107	} else {
108	$this->client->getLogger()->notice(
109	'File cache set failed',
110	array('key' => $key, 'file' => $storageFile)
111	);
112	}
113	}
114
115	public function delete($key)
116	{
117	$file = $this->getCacheFile($key);
118	if (file_exists($file) && !unlink($file)) {
119	$this->client->getLogger()->error(
120	'File cache delete failed',
121	array('key' => $key, 'file' => $file)
122	);
123	throw new Google_Cache_Exception("Cache file could not be deleted");
124	}
125
126	$this->client->getLogger()->debug(
127	'File cache delete',
128	array('key' => $key, 'file' => $file)
129	);
130	}
131
132	private function getWriteableCacheFile($file)
133	{
134	return $this->getCacheFile($file, true);
135	}
136
137	private function getCacheFile($file, $forWrite = false)
138	{
139	return $this->getCacheDir($file, $forWrite) . '/' . md5($file);
140	}
141
142	private function getCacheDir($file, $forWrite)
143	{
144	// use the first 2 characters of the hash as a directory prefix
145	// this should prevent slowdowns due to huge directory listings
146	// and thus give some basic amount of scalability
147	$storageDir = $this->path . '/' . substr(md5($file), 0, 2);
148	if ($forWrite && ! is_dir($storageDir)) {
149	if (! mkdir($storageDir, 0700, true)) {
150	$this->client->getLogger()->error(
151	'File cache creation failed',
152	array('dir' => $storageDir)
153	);
154	throw new Google_Cache_Exception("Could not create storage directory: $storageDir");
155	}
156	}
157	return $storageDir;
158	}
159
160	private function acquireReadLock($storageFile)
161	{
162	return $this->acquireLock(LOCK_SH, $storageFile);
163	}
164
165	private function acquireWriteLock($storageFile)
166	{
167	$rc = $this->acquireLock(LOCK_EX, $storageFile);
168	if (!$rc) {
169	$this->client->getLogger()->notice(
170	'File cache write lock failed',
171	array('file' => $storageFile)
172	);
173	$this->delete($storageFile);
174	}
175	return $rc;
176	}
177
178	private function acquireLock($type, $storageFile)
179	{
180	$mode = $type == LOCK_EX ? "w" : "r";
181	$this->fh = fopen($storageFile, $mode);
182	if (!$this->fh) {
183	$this->client->getLogger()->error(
184	'Failed to open file during lock acquisition',
185	array('file' => $storageFile)
186	);
187	return false;
188	}
189	if ($type == LOCK_EX) {
190	chmod($storageFile, 0600);
191	}
192	$count = 0;
193	while (!flock($this->fh, $type \| LOCK_NB)) {
194	// Sleep for 10ms.
195	usleep(10000);
196	if (++$count < self::MAX_LOCK_RETRIES) {
197	return false;
198	}
199	}
200	return true;
201	}
202
203	public function unlock($storageFile)
204	{
205	if ($this->fh) {
206	flock($this->fh, LOCK_UN);
207	}
208	}
209	}
210