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   1  <?php
   2  /**
   3   * Object Cache API
   4   *
   5   * @link http://codex.wordpress.org/Function_Reference/WP_Cache
   6   *
   7   * @package WordPress
   8   * @subpackage Cache
   9   */
  10  
  11  /**
  12   * Adds data to the cache, if the cache key doesn't already exist.
  13   *
  14   * @since 2.0.0
  15   * @uses $wp_object_cache Object Cache Class
  16   * @see WP_Object_Cache::add()
  17   *
  18   * @param int|string $key The cache key to use for retrieval later
  19   * @param mixed $data The data to add to the cache store
  20   * @param string $group The group to add the cache to
  21   * @param int $expire When the cache data should be expired
  22   * @return bool False if cache key and group already exist, true on success
  23   */
  24  function wp_cache_add( $key, $data, $group = '', $expire = 0 ) {
  25      global $wp_object_cache;
  26  
  27      return $wp_object_cache->add( $key, $data, $group, (int) $expire );
  28  }
  29  
  30  /**
  31   * Closes the cache.
  32   *
  33   * This function has ceased to do anything since WordPress 2.5. The
  34   * functionality was removed along with the rest of the persistent cache. This
  35   * does not mean that plugins can't implement this function when they need to
  36   * make sure that the cache is cleaned up after WordPress no longer needs it.
  37   *
  38   * @since 2.0.0
  39   *
  40   * @return bool Always returns True
  41   */
  42  function wp_cache_close() {
  43      return true;
  44  }
  45  
  46  /**
  47   * Decrement numeric cache item's value
  48   *
  49   * @since 3.3.0
  50   * @uses $wp_object_cache Object Cache Class
  51   * @see WP_Object_Cache::decr()
  52   *
  53   * @param int|string $key The cache key to increment
  54   * @param int $offset The amount by which to decrement the item's value. Default is 1.
  55   * @param string $group The group the key is in.
  56   * @return false|int False on failure, the item's new value on success.
  57   */
  58  function wp_cache_decr( $key, $offset = 1, $group = '' ) {
  59      global $wp_object_cache;
  60  
  61      return $wp_object_cache->decr( $key, $offset, $group );
  62  }
  63  
  64  /**
  65   * Removes the cache contents matching key and group.
  66   *
  67   * @since 2.0.0
  68   * @uses $wp_object_cache Object Cache Class
  69   * @see WP_Object_Cache::delete()
  70   *
  71   * @param int|string $key What the contents in the cache are called
  72   * @param string $group Where the cache contents are grouped
  73   * @return bool True on successful removal, false on failure
  74   */
  75  function wp_cache_delete($key, $group = '') {
  76      global $wp_object_cache;
  77  
  78      return $wp_object_cache->delete($key, $group);
  79  }
  80  
  81  /**
  82   * Removes all cache items.
  83   *
  84   * @since 2.0.0
  85   * @uses $wp_object_cache Object Cache Class
  86   * @see WP_Object_Cache::flush()
  87   *
  88   * @return bool False on failure, true on success
  89   */
  90  function wp_cache_flush() {
  91      global $wp_object_cache;
  92  
  93      return $wp_object_cache->flush();
  94  }
  95  
  96  /**
  97   * Retrieves the cache contents from the cache by key and group.
  98   *
  99   * @since 2.0.0
 100   * @uses $wp_object_cache Object Cache Class
 101   * @see WP_Object_Cache::get()
 102   *
 103   * @param int|string $key What the contents in the cache are called
 104   * @param string $group Where the cache contents are grouped
 105   * @param bool $force Whether to force an update of the local cache from the persistent cache (default is false)
 106   * @param &bool $found Whether key was found in the cache. Disambiguates a return of false, a storable value.
 107   * @return bool|mixed False on failure to retrieve contents or the cache
 108   *        contents on success
 109   */
 110  function wp_cache_get( $key, $group = '', $force = false, &$found = null ) {
 111      global $wp_object_cache;
 112  
 113      return $wp_object_cache->get( $key, $group, $force, $found );
 114  }
 115  
 116  /**
 117   * Increment numeric cache item's value
 118   *
 119   * @since 3.3.0
 120   * @uses $wp_object_cache Object Cache Class
 121   * @see WP_Object_Cache::incr()
 122   *
 123   * @param int|string $key The cache key to increment
 124   * @param int $offset The amount by which to increment the item's value. Default is 1.
 125   * @param string $group The group the key is in.
 126   * @return false|int False on failure, the item's new value on success.
 127   */
 128  function wp_cache_incr( $key, $offset = 1, $group = '' ) {
 129      global $wp_object_cache;
 130  
 131      return $wp_object_cache->incr( $key, $offset, $group );
 132  }
 133  
 134  /**
 135   * Sets up Object Cache Global and assigns it.
 136   *
 137   * @since 2.0.0
 138   * @global WP_Object_Cache $wp_object_cache WordPress Object Cache
 139   */
 140  function wp_cache_init() {
 141      $GLOBALS['wp_object_cache'] = new WP_Object_Cache();
 142  }
 143  
 144  /**
 145   * Replaces the contents of the cache with new data.
 146   *
 147   * @since 2.0.0
 148   * @uses $wp_object_cache Object Cache Class
 149   * @see WP_Object_Cache::replace()
 150   *
 151   * @param int|string $key What to call the contents in the cache
 152   * @param mixed $data The contents to store in the cache
 153   * @param string $group Where to group the cache contents
 154   * @param int $expire When to expire the cache contents
 155   * @return bool False if not exists, true if contents were replaced
 156   */
 157  function wp_cache_replace( $key, $data, $group = '', $expire = 0 ) {
 158      global $wp_object_cache;
 159  
 160      return $wp_object_cache->replace( $key, $data, $group, (int) $expire );
 161  }
 162  
 163  /**
 164   * Saves the data to the cache.
 165   *
 166   * @since 2.0
 167   * @uses $wp_object_cache Object Cache Class
 168   * @see WP_Object_Cache::set()
 169   *
 170   * @param int|string $key What to call the contents in the cache
 171   * @param mixed $data The contents to store in the cache
 172   * @param string $group Where to group the cache contents
 173   * @param int $expire When to expire the cache contents
 174   * @return bool False on failure, true on success
 175   */
 176  function wp_cache_set( $key, $data, $group = '', $expire = 0 ) {
 177      global $wp_object_cache;
 178  
 179      return $wp_object_cache->set( $key, $data, $group, (int) $expire );
 180  }
 181  
 182  /**
 183   * Switch the interal blog id.
 184   *
 185   * This changes the blog id used to create keys in blog specific groups.
 186   *
 187   * @since 3.5.0
 188   *
 189   * @param int $blog_id Blog ID
 190   */
 191  function wp_cache_switch_to_blog( $blog_id ) {
 192      global $wp_object_cache;
 193  
 194      return $wp_object_cache->switch_to_blog( $blog_id );
 195  }
 196  
 197  /**
 198   * Adds a group or set of groups to the list of global groups.
 199   *
 200   * @since 2.6.0
 201   *
 202   * @param string|array $groups A group or an array of groups to add
 203   */
 204  function wp_cache_add_global_groups( $groups ) {
 205      global $wp_object_cache;
 206  
 207      return $wp_object_cache->add_global_groups( $groups );
 208  }
 209  
 210  /**
 211   * Adds a group or set of groups to the list of non-persistent groups.
 212   *
 213   * @since 2.6.0
 214   *
 215   * @param string|array $groups A group or an array of groups to add
 216   */
 217  function wp_cache_add_non_persistent_groups( $groups ) {
 218      // Default cache doesn't persist so nothing to do here.
 219      return;
 220  }
 221  
 222  /**
 223   * Reset internal cache keys and structures. If the cache backend uses global
 224   * blog or site IDs as part of its cache keys, this function instructs the
 225   * backend to reset those keys and perform any cleanup since blog or site IDs
 226   * have changed since cache init.
 227   *
 228   * This function is deprecated. Use wp_cache_switch_to_blog() instead of this
 229   * function when preparing the cache for a blog switch. For clearing the cache
 230   * during unit tests, consider using wp_cache_init(). wp_cache_init() is not
 231   * recommended outside of unit tests as the performance penality for using it is
 232   * high.
 233   *
 234   * @since 2.6.0
 235   * @deprecated 3.5.0
 236   */
 237  function wp_cache_reset() {
 238      _deprecated_function( __FUNCTION__, '3.5' );
 239  
 240      global $wp_object_cache;
 241  
 242      return $wp_object_cache->reset();
 243  }
 244  
 245  /**
 246   * WordPress Object Cache
 247   *
 248   * The WordPress Object Cache is used to save on trips to the database. The
 249   * Object Cache stores all of the cache data to memory and makes the cache
 250   * contents available by using a key, which is used to name and later retrieve
 251   * the cache contents.
 252   *
 253   * The Object Cache can be replaced by other caching mechanisms by placing files
 254   * in the wp-content folder which is looked at in wp-settings. If that file
 255   * exists, then this file will not be included.
 256   *
 257   * @package WordPress
 258   * @subpackage Cache
 259   * @since 2.0
 260   */
 261  class WP_Object_Cache {
 262  
 263      /**
 264       * Holds the cached objects
 265       *
 266       * @var array
 267       * @access private
 268       * @since 2.0.0
 269       */
 270      var $cache = array ();
 271  
 272      /**
 273       * The amount of times the cache data was already stored in the cache.
 274       *
 275       * @since 2.5.0
 276       * @access private
 277       * @var int
 278       */
 279      var $cache_hits = 0;
 280  
 281      /**
 282       * Amount of times the cache did not have the request in cache
 283       *
 284       * @var int
 285       * @access public
 286       * @since 2.0.0
 287       */
 288      var $cache_misses = 0;
 289  
 290      /**
 291       * List of global groups
 292       *
 293       * @var array
 294       * @access protected
 295       * @since 3.0.0
 296       */
 297      var $global_groups = array();
 298  
 299      /**
 300       * The blog prefix to prepend to keys in non-global groups.
 301       *
 302       * @var int
 303       * @access private
 304       * @since 3.5.0
 305       */
 306      var $blog_prefix;
 307  
 308      /**
 309       * Adds data to the cache if it doesn't already exist.
 310       *
 311       * @uses WP_Object_Cache::_exists Checks to see if the cache already has data.
 312       * @uses WP_Object_Cache::set Sets the data after the checking the cache
 313       *        contents existence.
 314       *
 315       * @since 2.0.0
 316       *
 317       * @param int|string $key What to call the contents in the cache
 318       * @param mixed $data The contents to store in the cache
 319       * @param string $group Where to group the cache contents
 320       * @param int $expire When to expire the cache contents
 321       * @return bool False if cache key and group already exist, true on success
 322       */
 323  	function add( $key, $data, $group = 'default', $expire = 0 ) {
 324          if ( wp_suspend_cache_addition() )
 325              return false;
 326  
 327          if ( empty( $group ) )
 328              $group = 'default';
 329  
 330          $id = $key;
 331          if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) )
 332              $id = $this->blog_prefix . $key;
 333  
 334          if ( $this->_exists( $id, $group ) )
 335              return false;
 336  
 337          return $this->set( $key, $data, $group, (int) $expire );
 338      }
 339  
 340      /**
 341       * Sets the list of global groups.
 342       *
 343       * @since 3.0.0
 344       *
 345       * @param array $groups List of groups that are global.
 346       */
 347  	function add_global_groups( $groups ) {
 348          $groups = (array) $groups;
 349  
 350          $groups = array_fill_keys( $groups, true );
 351          $this->global_groups = array_merge( $this->global_groups, $groups );
 352      }
 353  
 354      /**
 355       * Decrement numeric cache item's value
 356       *
 357       * @since 3.3.0
 358       *
 359       * @param int|string $key The cache key to increment
 360       * @param int $offset The amount by which to decrement the item's value. Default is 1.
 361       * @param string $group The group the key is in.
 362       * @return false|int False on failure, the item's new value on success.
 363       */
 364  	function decr( $key, $offset = 1, $group = 'default' ) {
 365          if ( empty( $group ) )
 366              $group = 'default';
 367  
 368          if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) )
 369              $key = $this->blog_prefix . $key;
 370  
 371          if ( ! $this->_exists( $key, $group ) )
 372              return false;
 373  
 374          if ( ! is_numeric( $this->cache[ $group ][ $key ] ) )
 375              $this->cache[ $group ][ $key ] = 0;
 376  
 377          $offset = (int) $offset;
 378  
 379          $this->cache[ $group ][ $key ] -= $offset;
 380  
 381          if ( $this->cache[ $group ][ $key ] < 0 )
 382              $this->cache[ $group ][ $key ] = 0;
 383  
 384          return $this->cache[ $group ][ $key ];
 385      }
 386  
 387      /**
 388       * Remove the contents of the cache key in the group
 389       *
 390       * If the cache key does not exist in the group and $force parameter is set
 391       * to false, then nothing will happen. The $force parameter is set to false
 392       * by default.
 393       *
 394       * @since 2.0.0
 395       *
 396       * @param int|string $key What the contents in the cache are called
 397       * @param string $group Where the cache contents are grouped
 398       * @param bool $force Optional. Whether to force the unsetting of the cache
 399       *        key in the group
 400       * @return bool False if the contents weren't deleted and true on success
 401       */
 402  	function delete($key, $group = 'default', $force = false) {
 403          if ( empty( $group ) )
 404              $group = 'default';
 405  
 406          if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) )
 407              $key = $this->blog_prefix . $key;
 408  
 409          if ( ! $force && ! $this->_exists( $key, $group ) )
 410              return false;
 411  
 412          unset( $this->cache[$group][$key] );
 413          return true;
 414      }
 415  
 416      /**
 417       * Clears the object cache of all data
 418       *
 419       * @since 2.0.0
 420       *
 421       * @return bool Always returns true
 422       */
 423  	function flush() {
 424          $this->cache = array ();
 425  
 426          return true;
 427      }
 428  
 429      /**
 430       * Retrieves the cache contents, if it exists
 431       *
 432       * The contents will be first attempted to be retrieved by searching by the
 433       * key in the cache group. If the cache is hit (success) then the contents
 434       * are returned.
 435       *
 436       * On failure, the number of cache misses will be incremented.
 437       *
 438       * @since 2.0.0
 439       *
 440       * @param int|string $key What the contents in the cache are called
 441       * @param string $group Where the cache contents are grouped
 442       * @param string $force Whether to force a refetch rather than relying on the local cache (default is false)
 443       * @return bool|mixed False on failure to retrieve contents or the cache
 444       *        contents on success
 445       */
 446  	function get( $key, $group = 'default', $force = false, &$found = null ) {
 447          if ( empty( $group ) )
 448              $group = 'default';
 449  
 450          if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) )
 451              $key = $this->blog_prefix . $key;
 452  
 453          if ( $this->_exists( $key, $group ) ) {
 454              $found = true;
 455              $this->cache_hits += 1;
 456              if ( is_object($this->cache[$group][$key]) )
 457                  return clone $this->cache[$group][$key];
 458              else
 459                  return $this->cache[$group][$key];
 460          }
 461  
 462          $found = false;
 463          $this->cache_misses += 1;
 464          return false;
 465      }
 466  
 467      /**
 468       * Increment numeric cache item's value
 469       *
 470       * @since 3.3.0
 471       *
 472       * @param int|string $key The cache key to increment
 473       * @param int $offset The amount by which to increment the item's value. Default is 1.
 474       * @param string $group The group the key is in.
 475       * @return false|int False on failure, the item's new value on success.
 476       */
 477  	function incr( $key, $offset = 1, $group = 'default' ) {
 478          if ( empty( $group ) )
 479              $group = 'default';
 480  
 481          if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) )
 482              $key = $this->blog_prefix . $key;
 483  
 484          if ( ! $this->_exists( $key, $group ) )
 485              return false;
 486  
 487          if ( ! is_numeric( $this->cache[ $group ][ $key ] ) )
 488              $this->cache[ $group ][ $key ] = 0;
 489  
 490          $offset = (int) $offset;
 491  
 492          $this->cache[ $group ][ $key ] += $offset;
 493  
 494          if ( $this->cache[ $group ][ $key ] < 0 )
 495              $this->cache[ $group ][ $key ] = 0;
 496  
 497          return $this->cache[ $group ][ $key ];
 498      }
 499  
 500      /**
 501       * Replace the contents in the cache, if contents already exist
 502       *
 503       * @since 2.0.0
 504       * @see WP_Object_Cache::set()
 505       *
 506       * @param int|string $key What to call the contents in the cache
 507       * @param mixed $data The contents to store in the cache
 508       * @param string $group Where to group the cache contents
 509       * @param int $expire When to expire the cache contents
 510       * @return bool False if not exists, true if contents were replaced
 511       */
 512  	function replace( $key, $data, $group = 'default', $expire = 0 ) {
 513          if ( empty( $group ) )
 514              $group = 'default';
 515  
 516          $id = $key;
 517          if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) )
 518              $id = $this->blog_prefix . $key;
 519  
 520          if ( ! $this->_exists( $id, $group ) )
 521              return false;
 522  
 523          return $this->set( $key, $data, $group, (int) $expire );
 524      }
 525  
 526      /**
 527       * Reset keys
 528       *
 529       * @since 3.0.0
 530       * @deprecated 3.5.0
 531       */
 532  	function reset() {
 533          _deprecated_function( __FUNCTION__, '3.5', 'switch_to_blog()' );
 534  
 535          // Clear out non-global caches since the blog ID has changed.
 536          foreach ( array_keys( $this->cache ) as $group ) {
 537              if ( ! isset( $this->global_groups[ $group ] ) )
 538                  unset( $this->cache[ $group ] );
 539          }
 540      }
 541  
 542      /**
 543       * Sets the data contents into the cache
 544       *
 545       * The cache contents is grouped by the $group parameter followed by the
 546       * $key. This allows for duplicate ids in unique groups. Therefore, naming of
 547       * the group should be used with care and should follow normal function
 548       * naming guidelines outside of core WordPress usage.
 549       *
 550       * The $expire parameter is not used, because the cache will automatically
 551       * expire for each time a page is accessed and PHP finishes. The method is
 552       * more for cache plugins which use files.
 553       *
 554       * @since 2.0.0
 555       *
 556       * @param int|string $key What to call the contents in the cache
 557       * @param mixed $data The contents to store in the cache
 558       * @param string $group Where to group the cache contents
 559       * @param int $expire Not Used
 560       * @return bool Always returns true
 561       */
 562  	function set( $key, $data, $group = 'default', $expire = 0 ) {
 563          if ( empty( $group ) )
 564              $group = 'default';
 565  
 566          if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) )
 567              $key = $this->blog_prefix . $key;
 568  
 569          if ( is_object( $data ) )
 570              $data = clone $data;
 571  
 572          $this->cache[$group][$key] = $data;
 573          return true;
 574      }
 575  
 576      /**
 577       * Echoes the stats of the caching.
 578       *
 579       * Gives the cache hits, and cache misses. Also prints every cached group,
 580       * key and the data.
 581       *
 582       * @since 2.0.0
 583       */
 584  	function stats() {
 585          echo "<p>";
 586          echo "<strong>Cache Hits:</strong> {$this->cache_hits}<br />";
 587          echo "<strong>Cache Misses:</strong> {$this->cache_misses}<br />";
 588          echo "</p>";
 589          echo '<ul>';
 590          foreach ($this->cache as $group => $cache) {
 591              echo "<li><strong>Group:</strong> $group - ( " . number_format( strlen( serialize( $cache ) ) / 1024, 2 ) . 'k )</li>';
 592          }
 593          echo '</ul>';
 594      }
 595  
 596      /**
 597       * Switch the interal blog id.
 598       *
 599       * This changes the blog id used to create keys in blog specific groups.
 600       *
 601       * @since 3.5.0
 602       *
 603       * @param int $blog_id Blog ID
 604       */
 605  	function switch_to_blog( $blog_id ) {
 606          $blog_id = (int) $blog_id;
 607          $this->blog_prefix = $this->multisite ? $blog_id . ':' : '';
 608      }
 609  
 610      /**
 611       * Utility function to determine whether a key exists in the cache.
 612       *
 613       * @since 3.4.0
 614       *
 615       * @access protected
 616       */
 617  	protected function _exists( $key, $group ) {
 618          return isset( $this->cache[ $group ] ) && ( isset( $this->cache[ $group ][ $key ] ) || array_key_exists( $key, $this->cache[ $group ] ) );
 619      }
 620  
 621      /**
 622       * Sets up object properties; PHP 5 style constructor
 623       *
 624       * @since 2.0.8
 625       * @return null|WP_Object_Cache If cache is disabled, returns null.
 626       */
 627  	function __construct() {
 628          global $blog_id;
 629  
 630          $this->multisite = is_multisite();
 631          $this->blog_prefix =  $this->multisite ? $blog_id . ':' : '';
 632  
 633  
 634          /**
 635           * @todo This should be moved to the PHP4 style constructor, PHP5
 636           * already calls __destruct()
 637           */
 638          register_shutdown_function( array( $this, '__destruct' ) );
 639      }
 640  
 641      /**
 642       * Will save the object cache before object is completely destroyed.
 643       *
 644       * Called upon object destruction, which should be when PHP ends.
 645       *
 646       * @since  2.0.8
 647       *
 648       * @return bool True value. Won't be used by PHP
 649       */
 650  	function __destruct() {
 651          return true;
 652      }
 653  }