1: <?php
  2: 
  3: /**
  4:  * This file is part of the Nette Framework (https://nette.org)
  5:  * Copyright (c) 2004 David Grudl (https://davidgrudl.com)
  6:  */
  7: 
  8: namespace Nette\Caching\Storages;
  9: 
 10: use Nette;
 11: use 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, 'c+b');
151:         if ($handle) {
152:             $this->locks[$key] = $handle;
153:             flock($handle, LOCK_EX);
154:         }
155:     }
156: 
157: 
158:     /**
159:      * Writes item into the cache.
160:      * @param  string key
161:      * @param  mixed  data
162:      * @param  array  dependencies
163:      * @return void
164:      */
165:     public function write($key, $data, array $dp)
166:     {
167:         $meta = array(
168:             self::META_TIME => microtime(),
169:         );
170: 
171:         if (isset($dp[Cache::EXPIRATION])) {
172:             if (empty($dp[Cache::SLIDING])) {
173:                 $meta[self::META_EXPIRE] = $dp[Cache::EXPIRATION] + time(); // absolute time
174:             } else {
175:                 $meta[self::META_DELTA] = (int) $dp[Cache::EXPIRATION]; // sliding time
176:             }
177:         }
178: 
179:         if (isset($dp[Cache::ITEMS])) {
180:             foreach ((array) $dp[Cache::ITEMS] as $item) {
181:                 $depFile = $this->getCacheFile($item);
182:                 $m = $this->readMetaAndLock($depFile, LOCK_SH);
183:                 $meta[self::META_ITEMS][$depFile] = $m[self::META_TIME]; // may be NULL
184:                 unset($m);
185:             }
186:         }
187: 
188:         if (isset($dp[Cache::CALLBACKS])) {
189:             $meta[self::META_CALLBACKS] = $dp[Cache::CALLBACKS];
190:         }
191: 
192:         if (!isset($this->locks[$key])) {
193:             $this->lock($key);
194:             if (!isset($this->locks[$key])) {
195:                 return;
196:             }
197:         }
198:         $handle = $this->locks[$key];
199:         unset($this->locks[$key]);
200: 
201:         $cacheFile = $this->getCacheFile($key);
202: 
203:         if (isset($dp[Cache::TAGS]) || isset($dp[Cache::PRIORITY])) {
204:             if (!$this->journal) {
205:                 throw new Nette\InvalidStateException('CacheJournal has not been provided.');
206:             }
207:             $this->journal->write($cacheFile, $dp);
208:         }
209: 
210:         ftruncate($handle, 0);
211: 
212:         if (!is_string($data)) {
213:             $data = serialize($data);
214:             $meta[self::META_SERIALIZED] = TRUE;
215:         }
216: 
217:         $head = serialize($meta) . '?>';
218:         $head = '<?php //netteCache[01]' . str_pad((string) strlen($head), 6, '0', STR_PAD_LEFT) . $head;
219:         $headLen = strlen($head);
220:         $dataLen = strlen($data);
221: 
222:         do {
223:             if (fwrite($handle, str_repeat("\x00", $headLen), $headLen) !== $headLen) {
224:                 break;
225:             }
226: 
227:             if (fwrite($handle, $data, $dataLen) !== $dataLen) {
228:                 break;
229:             }
230: 
231:             fseek($handle, 0);
232:             if (fwrite($handle, $head, $headLen) !== $headLen) {
233:                 break;
234:             }
235: 
236:             flock($handle, LOCK_UN);
237:             fclose($handle);
238:             return;
239:         } while (FALSE);
240: 
241:         $this->delete($cacheFile, $handle);
242:     }
243: 
244: 
245:     /**
246:      * Removes item from the cache.
247:      * @param  string key
248:      * @return void
249:      */
250:     public function remove($key)
251:     {
252:         unset($this->locks[$key]);
253:         $this->delete($this->getCacheFile($key));
254:     }
255: 
256: 
257:     /**
258:      * Removes items from the cache by conditions & garbage collector.
259:      * @param  array  conditions
260:      * @return void
261:      */
262:     public function clean(array $conditions)
263:     {
264:         $all = !empty($conditions[Cache::ALL]);
265:         $collector = empty($conditions);
266: 
267:         // cleaning using file iterator
268:         if ($all || $collector) {
269:             $now = time();
270:             foreach (Nette\Utils\Finder::find('_*')->from($this->dir)->childFirst() as $entry) {
271:                 $path = (string) $entry;
272:                 if ($entry->isDir()) { // collector: remove empty dirs
273:                     @rmdir($path); // @ - removing dirs is not necessary
274:                     continue;
275:                 }
276:                 if ($all) {
277:                     $this->delete($path);
278: 
279:                 } else { // collector
280:                     $meta = $this->readMetaAndLock($path, LOCK_SH);
281:                     if (!$meta) {
282:                         continue;
283:                     }
284: 
285:                     if ((!empty($meta[self::META_DELTA]) && filemtime($meta[self::FILE]) + $meta[self::META_DELTA] < $now)
286:                         || (!empty($meta[self::META_EXPIRE]) && $meta[self::META_EXPIRE] < $now)
287:                     ) {
288:                         $this->delete($path, $meta[self::HANDLE]);
289:                         continue;
290:                     }
291: 
292:                     flock($meta[self::HANDLE], LOCK_UN);
293:                     fclose($meta[self::HANDLE]);
294:                 }
295:             }
296: 
297:             if ($this->journal) {
298:                 $this->journal->clean($conditions);
299:             }
300:             return;
301:         }
302: 
303:         // cleaning using journal
304:         if ($this->journal) {
305:             foreach ($this->journal->clean($conditions) as $file) {
306:                 $this->delete($file);
307:             }
308:         }
309:     }
310: 
311: 
312:     /**
313:      * Reads cache data from disk.
314:      * @param  string  file path
315:      * @param  int     lock mode
316:      * @return array|NULL
317:      */
318:     protected function readMetaAndLock($file, $lock)
319:     {
320:         $handle = @fopen($file, 'r+b'); // @ - file may not exist
321:         if (!$handle) {
322:             return NULL;
323:         }
324: 
325:         flock($handle, $lock);
326: 
327:         $head = stream_get_contents($handle, self::META_HEADER_LEN);
328:         if ($head && strlen($head) === self::META_HEADER_LEN) {
329:             $size = (int) substr($head, -6);
330:             $meta = stream_get_contents($handle, $size, self::META_HEADER_LEN);
331:             $meta = @unserialize($meta); // intentionally @
332:             if (is_array($meta)) {
333:                 $meta[self::FILE] = $file;
334:                 $meta[self::HANDLE] = $handle;
335:                 return $meta;
336:             }
337:         }
338: 
339:         flock($handle, LOCK_UN);
340:         fclose($handle);
341:         return NULL;
342:     }
343: 
344: 
345:     /**
346:      * Reads cache data from disk and closes cache file handle.
347:      * @param  array
348:      * @return mixed
349:      */
350:     protected function readData($meta)
351:     {
352:         $data = stream_get_contents($meta[self::HANDLE]);
353:         flock($meta[self::HANDLE], LOCK_UN);
354:         fclose($meta[self::HANDLE]);
355: 
356:         if (empty($meta[self::META_SERIALIZED])) {
357:             return $data;
358:         } else {
359:             return @unserialize($data); // intentionally @
360:         }
361:     }
362: 
363: 
364:     /**
365:      * Returns file name.
366:      * @param  string
367:      * @return string
368:      */
369:     protected function getCacheFile($key)
370:     {
371:         $file = urlencode($key);
372:         if ($this->useDirs && $a = strrpos($file, '%00')) { // %00 = urlencode(Nette\Caching\Cache::NAMESPACE_SEPARATOR)
373:             $file = substr_replace($file, '/_', $a, 3);
374:         }
375:         return $this->dir . '/_' . $file;
376:     }
377: 
378: 
379:     /**
380:      * Deletes and closes file.
381:      * @param  string
382:      * @param  resource
383:      * @return void
384:      */
385:     private static function delete($file, $handle = NULL)
386:     {
387:         if (@unlink($file)) { // @ - file may not already exist
388:             if ($handle) {
389:                 flock($handle, LOCK_UN);
390:                 fclose($handle);
391:             }
392:             return;
393:         }
394: 
395:         if (!$handle) {
396:             $handle = @fopen($file, 'r+'); // @ - file may not exist
397:         }
398:         if ($handle) {
399:             flock($handle, LOCK_EX);
400:             ftruncate($handle, 0);
401:             flock($handle, LOCK_UN);
402:             fclose($handle);
403:             @unlink($file); // @ - file may not already exist
404:         }
405:     }
406: 
407: }
408: