wp-includes/cache.php

   1 <?php
   2 function wp_cache_add($key, $data, $flag = '', $expire = 0) {
   3         global $wp_object_cache;
   4         $data = unserialize(serialize($data));
   5
   6         return $wp_object_cache->add($key, $data, $flag, $expire);
   7 }
   8
   9 function wp_cache_close() {
  10         global $wp_object_cache;
  11
  12         if ( ! isset($wp_object_cache) )
  13                 return;
  14         return $wp_object_cache->save();
  15 }
  16
  17 function wp_cache_delete($id, $flag = '') {
  18         global $wp_object_cache;
  19
  20         return $wp_object_cache->delete($id, $flag);
  21 }
  22
  23 function wp_cache_flush() {
  24         global $wp_object_cache;
  25
  26         return $wp_object_cache->flush();
  27 }
  28
  29 function wp_cache_get($id, $flag = '') {
  30         global $wp_object_cache;
  31
  32         return $wp_object_cache->get($id, $flag);
  33 }
  34
  35 function wp_cache_init() {
  36         $GLOBALS['wp_object_cache'] =& new WP_Object_Cache();
  37 }
  38
  39 function wp_cache_replace($key, $data, $flag = '', $expire = 0) {
  40         global $wp_object_cache;
  41         $data = unserialize(serialize($data));
  42
  43         return $wp_object_cache->replace($key, $data, $flag, $expire);
  44 }
  45
  46 function wp_cache_set($key, $data, $flag = '', $expire = 0) {
  47         global $wp_object_cache;
  48         $data = unserialize(serialize($data));
  49
  50         return $wp_object_cache->set($key, $data, $flag, $expire);
  51 }
  52
  53 define('CACHE_SERIAL_HEADER', "<?php\n/*");
  54 define('CACHE_SERIAL_FOOTER', "*/\n?".">");
  55
  56 class WP_Object_Cache {
  57         var $cache_dir;
  58         var $cache_enabled = false;
  59         var $expiration_time = 900;
  60         var $flock_filename = 'wp_object_cache.lock';
  61         var $mutex;
  62         var $cache = array ();
  63         var $dirty_objects = array ();
  64         var $non_existant_objects = array ();
  65         var $global_groups = array ('users', 'userlogins', 'usermeta');
  66         var $non_persistent_groups = array('comment');
  67         var $blog_id;
  68         var $cold_cache_hits = 0;
  69         var $warm_cache_hits = 0;
  70         var $cache_misses = 0;
  71         var $secret = '';
  72
  73         function acquire_lock() {
  74                 // Acquire a write lock.
  75                 $this->mutex = @fopen($this->cache_dir.$this->flock_filename, 'w');
  76                 if ( false == $this->mutex)
  77                         return false;
  78                 flock($this->mutex, LOCK_EX);
  79                 return true;
  80         }
  81
  82         function add($id, $data, $group = 'default', $expire = '') {
  83                 if (empty ($group))
  84                         $group = 'default';
  85
  86                 if (false !== $this->get($id, $group, false))
  87                         return false;
  88
  89                 return $this->set($id, $data, $group, $expire);
  90         }
  91
  92         function delete($id, $group = 'default', $force = false) {
  93                 if (empty ($group))
  94                         $group = 'default';
  95
  96                 if (!$force && false === $this->get($id, $group, false))
  97                         return false;
  98
  99                 unset ($this->cache[$group][$id]);
 100                 $this->non_existant_objects[$group][$id] = true;
 101                 $this->dirty_objects[$group][] = $id;
 102                 return true;
 103         }
 104
 105         function flush() {
 106                 if ( !$this->cache_enabled )
 107                         return true;
 108
 109                 if ( ! $this->acquire_lock() )
 110                         return false;
 111
 112                 $this->rm_cache_dir();
 113                 $this->cache = array ();
 114                 $this->dirty_objects = array ();
 115                 $this->non_existant_objects = array ();
 116
 117                 $this->release_lock();
 118
 119                 return true;
 120         }
 121
 122         function get($id, $group = 'default', $count_hits = true) {
 123                 if (empty ($group))
 124                         $group = 'default';
 125
 126                 if (isset ($this->cache[$group][$id])) {
 127                         if ($count_hits)
 128                                 $this->warm_cache_hits += 1;
 129                         return $this->cache[$group][$id];
 130                 }
 131
 132                 if (isset ($this->non_existant_objects[$group][$id]))
 133                         return false;
 134
 135                 //  If caching is not enabled, we have to fall back to pulling from the DB.
 136                 if (!$this->cache_enabled) {
 137                         if (!isset ($this->cache[$group]))
 138                                 $this->load_group_from_db($group);
 139
 140                         if (isset ($this->cache[$group][$id])) {
 141                                 $this->cold_cache_hits += 1;
 142                                 return $this->cache[$group][$id];
 143                         }
 144
 145                         $this->non_existant_objects[$group][$id] = true;
 146                         $this->cache_misses += 1;
 147                         return false;
 148                 }
 149
 150                 $cache_file = $this->cache_dir.$this->get_group_dir($group)."/".$this->hash($id).'.php';
 151                 if (!file_exists($cache_file)) {
 152                         $this->non_existant_objects[$group][$id] = true;
 153                         $this->cache_misses += 1;
 154                         return false;
 155                 }
 156
 157                 // If the object has expired, remove it from the cache and return false to force
 158                 // a refresh.
 159                 $now = time();
 160                 if ((filemtime($cache_file) + $this->expiration_time) <= $now) {
 161                         $this->cache_misses += 1;
 162                         $this->delete($id, $group, true);
 163                         return false;
 164                 }
 165
 166                 $this->cache[$group][$id] = unserialize(base64_decode(substr(@ file_get_contents($cache_file), strlen(CACHE_SERIAL_HEADER), -strlen(CACHE_SERIAL_FOOTER))));
 167                 if (false === $this->cache[$group][$id])
 168                         $this->cache[$group][$id] = '';
 169
 170                 $this->cold_cache_hits += 1;
 171                 return $this->cache[$group][$id];
 172         }
 173
 174         function get_group_dir($group) {
 175                 if (false !== array_search($group, $this->global_groups))
 176                         return $group;
 177
 178                 return "{$this->blog_id}/$group";
 179         }
 180
 181         function hash($data) {
 182                 if ( function_exists('hash_hmac') ) {
 183                         return hash_hmac('md5', $data, $this->secret);
 184                 } else {
 185                         return md5($data . $this->secret);
 186                 }
 187         }
 188
 189         function load_group_from_db($group) {
 190                 return;
 191         }
 192
 193         function make_group_dir($group, $perms) {
 194                 $group_dir = $this->get_group_dir($group);
 195                 $make_dir = '';
 196                 foreach (split('/', $group_dir) as $subdir) {
 197                         $make_dir .= "$subdir/";
 198                         if (!file_exists($this->cache_dir.$make_dir)) {
 199                                 if (! @ mkdir($this->cache_dir.$make_dir))
 200                                         break;
 201                                 @ chmod($this->cache_dir.$make_dir, $perms);
 202                         }
 203
 204                         if (!file_exists($this->cache_dir.$make_dir."index.php")) {
 205                                 $file_perms = $perms & 0000666;
 206                                 @ touch($this->cache_dir.$make_dir."index.php");
 207                                 @ chmod($this->cache_dir.$make_dir."index.php", $file_perms);
 208                         }
 209                 }
 210
 211                 return $this->cache_dir."$group_dir/";
 212         }
 213
 214         function rm_cache_dir() {
 215                 $dir = $this->cache_dir;
 216                 $dir = rtrim($dir, DIRECTORY_SEPARATOR);
 217                 $top_dir = $dir;
 218                 $stack = array($dir);
 219                 $index = 0;
 220
 221                 while ($index < count($stack)) {
 222                         # Get indexed directory from stack
 223                         $dir = $stack[$index];
 224
 225                         $dh = @ opendir($dir);
 226                         if (!$dh)
 227                                 return false;
 228
 229                         while (($file = @ readdir($dh)) !== false) {
 230                                 if ($file == '.' or $file == '..')
 231                                         continue;
 232
 233                                 if (@ is_dir($dir . DIRECTORY_SEPARATOR . $file))
 234                                         $stack[] = $dir . DIRECTORY_SEPARATOR . $file;
 235                                 else if (@ is_file($dir . DIRECTORY_SEPARATOR . $file))
 236                                         @ unlink($dir . DIRECTORY_SEPARATOR . $file);
 237                         }
 238
 239                         $index++;
 240                 }
 241
 242                 $stack = array_reverse($stack);  // Last added dirs are deepest
 243                 foreach($stack as $dir) {
 244                         if ( $dir != $top_dir)
 245                                 @ rmdir($dir);
 246                 }
 247
 248         }
 249
 250         function release_lock() {
 251                 // Release write lock.
 252                 flock($this->mutex, LOCK_UN);
 253                 fclose($this->mutex);
 254         }
 255
 256         function replace($id, $data, $group = 'default', $expire = '') {
 257                 if (empty ($group))
 258                         $group = 'default';
 259
 260                 if (false === $this->get($id, $group, false))
 261                         return false;
 262
 263                 return $this->set($id, $data, $group, $expire);
 264         }
 265
 266         function set($id, $data, $group = 'default', $expire = '') {
 267                 if (empty ($group))
 268                         $group = 'default';
 269
 270                 if (NULL == $data)
 271                         $data = '';
 272
 273                 $this->cache[$group][$id] = $data;
 274                 unset ($this->non_existant_objects[$group][$id]);
 275                 $this->dirty_objects[$group][] = $id;
 276
 277                 return true;
 278         }
 279
 280         function save() {
 281                 //$this->stats();
 282
 283                 if (!$this->cache_enabled)
 284                         return true;
 285
 286                 if (empty ($this->dirty_objects))
 287                         return true;
 288
 289                 // Give the new dirs the same perms as wp-content.
 290                 $stat = stat(ABSPATH.'wp-content');
 291                 $dir_perms = $stat['mode'] & 0007777; // Get the permission bits.
 292                 $file_perms = $dir_perms & 0000666; // Remove execute bits for files.
 293
 294                 // Make the base cache dir.
 295                 if (!file_exists($this->cache_dir)) {
 296                         if (! @ mkdir($this->cache_dir))
 297                                 return false;
 298                         @ chmod($this->cache_dir, $dir_perms);
 299                 }
 300
 301                 if (!file_exists($this->cache_dir."index.php")) {
 302                         @ touch($this->cache_dir."index.php");
 303                         @ chmod($this->cache_dir."index.php", $file_perms);
 304                 }
 305
 306                 if ( ! $this->acquire_lock() )
 307                         return false;
 308
 309                 // Loop over dirty objects and save them.
 310                 $errors = 0;
 311                 foreach ($this->dirty_objects as $group => $ids) {
 312                         if ( in_array($group, $this->non_persistent_groups) )
 313                                 continue;
 314
 315                         $group_dir = $this->make_group_dir($group, $dir_perms);
 316
 317                         $ids = array_unique($ids);
 318                         foreach ($ids as $id) {
 319                                 $cache_file = $group_dir.$this->hash($id).'.php';
 320
 321                                 // Remove the cache file if the key is not set.
 322                                 if (!isset ($this->cache[$group][$id])) {
 323                                         if (file_exists($cache_file))
 324                                                 @ unlink($cache_file);
 325                                         continue;
 326                                 }
 327
 328                                 $temp_file = tempnam($group_dir, 'tmp');
 329                                 $serial = CACHE_SERIAL_HEADER.base64_encode(serialize($this->cache[$group][$id])).CACHE_SERIAL_FOOTER;
 330                                 $fd = @fopen($temp_file, 'w');
 331                                 if ( false === $fd ) {
 332                                         $errors++;
 333                                         continue;
 334                                 }
 335                                 fputs($fd, $serial);
 336                                 fclose($fd);
 337                                 if (!@ rename($temp_file, $cache_file)) {
 338                                         if (!@ copy($temp_file, $cache_file))
 339                                                 $errors++;
 340                                         @ unlink($temp_file);
 341                                 }
 342                                 @ chmod($cache_file, $file_perms);
 343                         }
 344                 }
 345
 346                 $this->dirty_objects = array();
 347
 348                 $this->release_lock();
 349
 350                 if ( $errors )
 351                         return false;
 352
 353                 return true;
 354         }
 355
 356         function stats() {
 357                 echo "<p>";
 358                 echo "<strong>Cold Cache Hits:</strong> {$this->cold_cache_hits}<br />";
 359                 echo "<strong>Warm Cache Hits:</strong> {$this->warm_cache_hits}<br />";
 360                 echo "<strong>Cache Misses:</strong> {$this->cache_misses}<br />";
 361                 echo "</p>";
 362
 363                 foreach ($this->cache as $group => $cache) {
 364                         echo "<p>";
 365                         echo "<strong>Group:</strong> $group<br />";
 366                         echo "<strong>Cache:</strong>";
 367                         echo "<pre>";
 368                         print_r($cache);
 369                         echo "</pre>";
 370                         if (isset ($this->dirty_objects[$group])) {
 371                                 echo "<strong>Dirty Objects:</strong>";
 372                                 echo "<pre>";
 373                                 print_r(array_unique($this->dirty_objects[$group]));
 374                                 echo "</pre>";
 375                                 echo "</p>";
 376                         }
 377                 }
 378         }
 379
 380         function WP_Object_Cache() {
 381                 return $this->__construct();
 382         }
 383
 384         function __construct() {
 385                 global $blog_id;
 386
 387                 register_shutdown_function(array(&$this, "__destruct"));
 388
 389                 if (defined('DISABLE_CACHE'))
 390                         return;
 391
 392                 if ( ! defined('ENABLE_CACHE') )
 393                         return;
 394
 395                 // Disable the persistent cache if safe_mode is on.
 396                 if ( ini_get('safe_mode') && ! defined('ENABLE_CACHE') )
 397                         return;
 398
 399                 if (defined('CACHE_PATH'))
 400                         $this->cache_dir = CACHE_PATH;
 401                 else
 402                         // Using the correct separator eliminates some cache flush errors on Windows
 403                         $this->cache_dir = ABSPATH.'wp-content'.DIRECTORY_SEPARATOR.'cache'.DIRECTORY_SEPARATOR;
 404
 405                 if (is_writable($this->cache_dir) && is_dir($this->cache_dir)) {
 406                                 $this->cache_enabled = true;
 407                 } else {
 408                         if (is_writable(ABSPATH.'wp-content')) {
 409                                 $this->cache_enabled = true;
 410                         }
 411                 }
 412
 413                 if (defined('CACHE_EXPIRATION_TIME'))
 414                         $this->expiration_time = CACHE_EXPIRATION_TIME;
 415
 416                 if ( defined('WP_SECRET') )
 417                         $this->secret = WP_SECRET;
 418                 else
 419                         $this->secret = DB_PASSWORD . DB_USER . DB_NAME . DB_HOST . ABSPATH;
 420
 421                 $this->blog_id = $this->hash($blog_id);
 422         }
 423
 424         function __destruct() {
 425                 $this->save();
 426                 return true;
 427         }
 428 }
 429 ?>