1: <?php
  2: 
  3: /**
  4:  * This file is part of the Nette Framework (https://nette.org)
  5:  * Copyright (c) 2004 David Grudl (http://davidgrudl.com)
  6:  */
  7: 
  8: namespace Nette\Caching\Storages;
  9: 
 10: use Nette,
 11:     Nette\Caching\Cache;
 12: 
 13: 
 14: /**
 15:  * Cache file storage.
 16:  *
 17:  * @author     David Grudl
 18:  */
 19: class FileStorage extends Nette\Object implements Nette\Caching\IStorage
 20: {
 21:     /**
 22:      * Atomic thread safe logic:
 23:      *
 24:      * 1) reading: open(r+b), lock(SH), read
 25:      *     - delete?: delete*, close
 26:      * 2) deleting: delete*
 27:      * 3) writing: open(r+b || wb), lock(EX), truncate*, write data, write meta, close
 28:      *
 29:      * delete* = try unlink, if fails (on NTFS) { lock(EX), truncate, close, unlink } else close (on ext3)
 30:      */
 31: 
 32:     /** @internal cache file structure */
 33:     const META_HEADER_LEN = 28, // 22b signature + 6b meta-struct size + serialized meta-struct + data
 34:     // meta structure: array of
 35:         META_TIME = 'time', // timestamp
 36:         META_SERIALIZED = 'serialized', // is content serialized?
 37:         META_EXPIRE = 'expire', // expiration timestamp
 38:         META_DELTA = 'delta', // relative (sliding) expiration
 39:         META_ITEMS = 'di', // array of dependent items (file => timestamp)
 40:         META_CALLBACKS = 'callbacks'; // array of callbacks (function, args)
 41: 
 42:     /** additional cache structure */
 43:     const FILE = 'file',
 44:         HANDLE = 'handle';
 45: 
 46: 
 47:     /** @var float  probability that the clean() routine is started */
 48:     public static $gcProbability = 0.001;
 49: 
 50:     /** @var bool */
 51:     public static $useDirectories = TRUE;
 52: 
 53:     /** @var string */
 54:     private $dir;
 55: 
 56:     /** @var bool */
 57:     private $useDirs;
 58: 
 59:     /** @var IJournal */
 60:     private $journal;
 61: 
 62:     /** @var array */
 63:     private $locks;
 64: 
 65: 
 66:     public function __construct($dir, IJournal $journal = NULL)
 67:     {
 68:         $this->dir = realpath($dir);
 69:         if ($this->dir === FALSE) {
 70:             throw new Nette\DirectoryNotFoundException("Directory '$dir' not found.");
 71:         }
 72: 
 73:         $this->useDirs = (bool) static::$useDirectories;
 74:         $this->journal = $journal;
 75: 
 76:         if (mt_rand() / mt_getrandmax() < static::$gcProbability) {
 77:             $this->clean(array());
 78:         }
 79:     }
 80: 
 81: 
 82:     /**
 83:      * Read from cache.
 84:      * @param  string key
 85:      * @return mixed|NULL
 86:      */
 87:     public function read($key)
 88:     {
 89:         $meta = $this->readMetaAndLock($this->getCacheFile($key), LOCK_SH);
 90:         if ($meta && $this->verify($meta)) {
 91:             return $this->readData($meta); // calls fclose()
 92: 
 93:         } else {
 94:             return NULL;
 95:         }
 96:     }
 97: 
 98: 
 99:     /**
100:      * Verifies dependencies.
101:      * @param  array
102:      * @return bool
103:      */
104:     private function verify($meta)
105:     {
106:         do {
107:             if (!empty($meta[self::META_DELTA])) {
108:                 // meta[file] was added by readMetaAndLock()
109:                 if (filemtime($meta[self::FILE]) + $meta[self::META_DELTA] < time()) {
110:                     break;
111:                 }
112:                 touch($meta[self::FILE]);
113: 
114:             } elseif (!empty($meta[self::META_EXPIRE]) && $meta[self::META_EXPIRE] < time()) {
115:                 break;
116:             }
117: 
118:             if (!empty($meta[self::META_CALLBACKS]) && !Cache::checkCallbacks($meta[self::META_CALLBACKS])) {
119:                 break;
120:             }
121: 
122:             if (!empty($meta[self::META_ITEMS])) {
123:                 foreach ($meta[self::META_ITEMS] as $depFile => $time) {
124:                     $m = $this->readMetaAndLock($depFile, LOCK_SH);
125:                     if ($m[self::META_TIME] !== $time || ($m && !$this->verify($m))) {
126:                         break 2;
127:                     }
128:                 }
129:             }
130: 
131:             return TRUE;
132:         } while (FALSE);
133: 
134:         $this->delete($meta[self::FILE], $meta[self::HANDLE]); // meta[handle] & meta[file] was added by readMetaAndLock()
135:         return FALSE;
136:     }
137: 
138: 
139:     /**
140:      * Prevents item reading and writing. Lock is released by write() or remove().
141:      * @param  string key
142:      * @return void
143:      */
144:     public function lock($key)
145:     {
146:         $cacheFile = $this->getCacheFile($key);
147:         if ($this->useDirs && !is_dir($dir = dirname($cacheFile))) {
148:             @mkdir($dir); // @ - directory may already exist
149:         }
150:         $handle = @fopen($cacheFile, 'r+b'); // @ - file may not exist
151:         if (!$handle) {
152:             $handle = fopen($cacheFile, 'wb');
153:             if (!$handle) {
154:                 return;
155:             }
156:         }
157: 
158:         $this->locks[$key] = $handle;
159:         flock($handle, LOCK_EX);
160:     }
161: 
162: 
163:     /**
164:      * Writes item into the cache.
165:      * @param  string key
166:      * @param  mixed  data
167:      * @param  array  dependencies
168:      * @return void
169:      */
170:     public function write($key, $data, array $dp)
171:     {
172:         $meta = array(
173:             self::META_TIME => microtime(),
174:         );
175: 
176:         if (isset($dp[Cache::EXPIRATION])) {
177:             if (empty($dp[Cache::SLIDING])) {
178:                 $meta[self::META_EXPIRE] = $dp[Cache::EXPIRATION] + time(); // absolute time
179:             } else {
180:                 $meta[self::META_DELTA] = (int) $dp[Cache::EXPIRATION]; // sliding time
181:             }
182:         }
183: 
184:         if (isset($dp[Cache::ITEMS])) {
185:             foreach ((array) $dp[Cache::ITEMS] as $item) {
186:                 $depFile = $this->getCacheFile($item);
187:                 $m = $this->readMetaAndLock($depFile, LOCK_SH);
188:                 $meta[self::META_ITEMS][$depFile] = $m[self::META_TIME]; // may be NULL
189:                 unset($m);
190:             }
191:         }
192: 
193:         if (isset($dp[Cache::CALLBACKS])) {
194:             $meta[self::META_CALLBACKS] = $dp[Cache::CALLBACKS];
195:         }
196: 
197:         if (!isset($this->locks[$key])) {
198:             $this->lock($key);
199:             if (!isset($this->locks[$key])) {
200:                 return;
201:             }
202:         }
203:         $handle = $this->locks[$key];
204:         unset($this->locks[$key]);
205: 
206:         $cacheFile = $this->getCacheFile($key);
207: 
208:         if (isset($dp[Cache::TAGS]) || isset($dp[Cache::PRIORITY])) {
209:             if (!$this->journal) {
210:                 throw new Nette\InvalidStateException('CacheJournal has not been provided.');
211:             }
212:             $this->journal->write($cacheFile, $dp);
213:         }
214: 
215:         ftruncate($handle, 0);
216: 
217:         if (!is_string($data)) {
218:             $data = serialize($data);
219:             $meta[self::META_SERIALIZED] = TRUE;
220:         }
221: 
222:         $head = serialize($meta) . '?>';
223:         $head = '<?php //netteCache[01]' . str_pad((string) strlen($head), 6, '0', STR_PAD_LEFT) . $head;
224:         $headLen = strlen($head);
225:         $dataLen = strlen($data);
226: 
227:         do {
228:             if (fwrite($handle, str_repeat("\x00", $headLen), $headLen) !== $headLen) {
229:                 break;
230:             }
231: 
232:             if (fwrite($handle, $data, $dataLen) !== $dataLen) {
233:                 break;
234:             }
235: 
236:             fseek($handle, 0);
237:             if (fwrite($handle, $head, $headLen) !== $headLen) {
238:                 break;
239:             }
240: 
241:             flock($handle, LOCK_UN);
242:             fclose($handle);
243:             return;
244:         } while (FALSE);
245: 
246:         $this->delete($cacheFile, $handle);
247:     }
248: 
249: 
250:     /**
251:      * Removes item from the cache.
252:      * @param  string key
253:      * @return void
254:      */
255:     public function remove($key)
256:     {
257:         unset($this->locks[$key]);
258:         $this->delete($this->getCacheFile($key));
259:     }
260: 
261: 
262:     /**
263:      * Removes items from the cache by conditions & garbage collector.
264:      * @param  array  conditions
265:      * @return void
266:      */
267:     public function clean(array $conditions)
268:     {
269:         $all = !empty($conditions[Cache::ALL]);
270:         $collector = empty($conditions);
271: 
272:         // cleaning using file iterator
273:         if ($all || $collector) {
274:             $now = time();
275:             foreach (Nette\Utils\Finder::find('_*')->from($this->dir)->childFirst() as $entry) {
276:                 $path = (string) $entry;
277:                 if ($entry->isDir()) { // collector: remove empty dirs
278:                     @rmdir($path); // @ - removing dirs is not necessary
279:                     continue;
280:                 }
281:                 if ($all) {
282:                     $this->delete($path);
283: 
284:                 } else { // collector
285:                     $meta = $this->readMetaAndLock($path, LOCK_SH);
286:                     if (!$meta) {
287:                         continue;
288:                     }
289: 
290:                     if ((!empty($meta[self::META_DELTA]) && filemtime($meta[self::FILE]) + $meta[self::META_DELTA] < $now)
291:                         || (!empty($meta[self::META_EXPIRE]) && $meta[self::META_EXPIRE] < $now)
292:                     ) {
293:                         $this->delete($path, $meta[self::HANDLE]);
294:                         continue;
295:                     }
296: 
297:                     flock($meta[self::HANDLE], LOCK_UN);
298:                     fclose($meta[self::HANDLE]);
299:                 }
300:             }
301: 
302:             if ($this->journal) {
303:                 $this->journal->clean($conditions);
304:             }
305:             return;
306:         }
307: 
308:         // cleaning using journal
309:         if ($this->journal) {
310:             foreach ($this->journal->clean($conditions) as $file) {
311:                 $this->delete($file);
312:             }
313:         }
314:     }
315: 
316: 
317:     /**
318:      * Reads cache data from disk.
319:      * @param  string  file path
320:      * @param  int     lock mode
321:      * @return array|NULL
322:      */
323:     protected function readMetaAndLock($file, $lock)
324:     {
325:         $handle = @fopen($file, 'r+b'); // @ - file may not exist
326:         if (!$handle) {
327:             return NULL;
328:         }
329: 
330:         flock($handle, $lock);
331: 
332:         $head = stream_get_contents($handle, self::META_HEADER_LEN);
333:         if ($head && strlen($head) === self::META_HEADER_LEN) {
334:             $size = (int) substr($head, -6);
335:             $meta = stream_get_contents($handle, $size, self::META_HEADER_LEN);
336:             $meta = @unserialize($meta); // intentionally @
337:             if (is_array($meta)) {
338:                 fseek($handle, $size + self::META_HEADER_LEN); // needed by PHP < 5.2.6
339:                 $meta[self::FILE] = $file;
340:                 $meta[self::HANDLE] = $handle;
341:                 return $meta;
342:             }
343:         }
344: 
345:         flock($handle, LOCK_UN);
346:         fclose($handle);
347:         return NULL;
348:     }
349: 
350: 
351:     /**
352:      * Reads cache data from disk and closes cache file handle.
353:      * @param  array
354:      * @return mixed
355:      */
356:     protected function readData($meta)
357:     {
358:         $data = stream_get_contents($meta[self::HANDLE]);
359:         flock($meta[self::HANDLE], LOCK_UN);
360:         fclose($meta[self::HANDLE]);
361: 
362:         if (empty($meta[self::META_SERIALIZED])) {
363:             return $data;
364:         } else {
365:             return @unserialize($data); // intentionally @
366:         }
367:     }
368: 
369: 
370:     /**
371:      * Returns file name.
372:      * @param  string
373:      * @return string
374:      */
375:     protected function getCacheFile($key)
376:     {
377:         $file = urlencode($key);
378:         if ($this->useDirs && $a = strrpos($file, '%00')) { // %00 = urlencode(Nette\Caching\Cache::NAMESPACE_SEPARATOR)
379:             $file = substr_replace($file, '/_', $a, 3);
380:         }
381:         return $this->dir . '/_' . $file;
382:     }
383: 
384: 
385:     /**
386:      * Deletes and closes file.
387:      * @param  string
388:      * @param  resource
389:      * @return void
390:      */
391:     private static function delete($file, $handle = NULL)
392:     {
393:         if (@unlink($file)) { // @ - file may not already exist
394:             if ($handle) {
395:                 flock($handle, LOCK_UN);
396:                 fclose($handle);
397:             }
398:             return;
399:         }
400: 
401:         if (!$handle) {
402:             $handle = @fopen($file, 'r+'); // @ - file may not exist
403:         }
404:         if ($handle) {
405:             flock($handle, LOCK_EX);
406:             ftruncate($handle, 0);
407:             flock($handle, LOCK_UN);
408:             fclose($handle);
409:             @unlink($file); // @ - file may not already exist
410:         }
411:     }
412: 
413: }
414: