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   1  <?php
   2  /**
   3   * The plugin API is located in this file, which allows for creating actions
   4   * and filters and hooking functions, and methods. The functions or methods will
   5   * then be run when the action or filter is called.
   6   *
   7   * The API callback examples reference functions, but can be methods of classes.
   8   * To hook methods, you'll need to pass an array one of two ways.
   9   *
  10   * Any of the syntaxes explained in the PHP documentation for the
  11   * {@link http://us2.php.net/manual/en/language.pseudo-types.php#language.types.callback 'callback'}
  12   * type are valid.
  13   *
  14   * Also see the {@link http://codex.wordpress.org/Plugin_API Plugin API} for
  15   * more information and examples on how to use a lot of these functions.
  16   *
  17   * @package WordPress
  18   * @subpackage Plugin
  19   * @since 1.5
  20   */
  21  
  22  /**
  23   * Hooks a function or method to a specific filter action.
  24   *
  25   * Filters are the hooks that WordPress launches to modify text of various types
  26   * before adding it to the database or sending it to the browser screen. Plugins
  27   * can specify that one or more of its PHP functions is executed to
  28   * modify specific types of text at these times, using the Filter API.
  29   *
  30   * To use the API, the following code should be used to bind a callback to the
  31   * filter.
  32   *
  33   * <code>
  34   * function example_hook($example) { echo $example; }
  35   * add_filter('example_filter', 'example_hook');
  36   * </code>
  37   *
  38   * In WordPress 1.5.1+, hooked functions can take extra arguments that are set
  39   * when the matching do_action() or apply_filters() call is run. The
  40   * $accepted_args allow for calling functions only when the number of args
  41   * match. Hooked functions can take extra arguments that are set when the
  42   * matching do_action() or apply_filters() call is run. For example, the action
  43   * comment_id_not_found will pass any functions that hook onto it the ID of the
  44   * requested comment.
  45   *
  46   * <strong>Note:</strong> the function will return true no matter if the
  47   * function was hooked fails or not. There are no checks for whether the
  48   * function exists beforehand and no checks to whether the <tt>$function_to_add
  49   * is even a string. It is up to you to take care and this is done for
  50   * optimization purposes, so everything is as quick as possible.
  51   *
  52   * @package WordPress
  53   * @subpackage Plugin
  54   * @since 0.71
  55   * @global array $wp_filter Stores all of the filters added in the form of
  56   *    wp_filter['tag']['array of priorities']['array of functions serialized']['array of ['array (functions, accepted_args)']']
  57   * @global array $merged_filters Tracks the tags that need to be merged for later. If the hook is added, it doesn't need to run through that process.
  58   *
  59   * @param string $tag The name of the filter to hook the $function_to_add to.
  60   * @param callback $function_to_add The name of the function to be called when the filter is applied.
  61   * @param int $priority optional. Used to specify the order in which the functions associated with a particular action are executed (default: 10). Lower numbers correspond with earlier execution, and functions with the same priority are executed in the order in which they were added to the action.
  62   * @param int $accepted_args optional. The number of arguments the function accept (default 1).
  63   * @return boolean true
  64   */
  65  function add_filter($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
  66      global $wp_filter, $merged_filters;
  67  
  68      $idx = _wp_filter_build_unique_id($tag, $function_to_add, $priority);
  69      $wp_filter[$tag][$priority][$idx] = array('function' => $function_to_add, 'accepted_args' => $accepted_args);
  70      unset( $merged_filters[ $tag ] );
  71      return true;
  72  }
  73  
  74  /**
  75   * Check if any filter has been registered for a hook.
  76   *
  77   * @package WordPress
  78   * @subpackage Plugin
  79   * @since 2.5
  80   * @global array $wp_filter Stores all of the filters
  81   *
  82   * @param string $tag The name of the filter hook.
  83   * @param callback $function_to_check optional.  If specified, return the priority of that function on this hook or false if not attached.
  84   * @return int|boolean Optionally returns the priority on that hook for the specified function.
  85   */
  86  function has_filter($tag, $function_to_check = false) {
  87      global $wp_filter;
  88  
  89      $has = !empty($wp_filter[$tag]);
  90      if ( false === $function_to_check || false == $has )
  91          return $has;
  92  
  93      if ( !$idx = _wp_filter_build_unique_id($tag, $function_to_check, false) )
  94          return false;
  95  
  96      foreach ( (array) array_keys($wp_filter[$tag]) as $priority ) {
  97          if ( isset($wp_filter[$tag][$priority][$idx]) )
  98              return $priority;
  99      }
 100  
 101      return false;
 102  }
 103  
 104  /**
 105   * Call the functions added to a filter hook.
 106   *
 107   * The callback functions attached to filter hook $tag are invoked by calling
 108   * this function. This function can be used to create a new filter hook by
 109   * simply calling this function with the name of the new hook specified using
 110   * the $tag parameter.
 111   *
 112   * The function allows for additional arguments to be added and passed to hooks.
 113   * <code>
 114   * function example_hook($string, $arg1, $arg2)
 115   * {
 116   *        //Do stuff
 117   *        return $string;
 118   * }
 119   * $value = apply_filters('example_filter', 'filter me', 'arg1', 'arg2');
 120   * </code>
 121   *
 122   * @package WordPress
 123   * @subpackage Plugin
 124   * @since 0.71
 125   * @global array $wp_filter Stores all of the filters
 126   * @global array $merged_filters Merges the filter hooks using this function.
 127   * @global array $wp_current_filter stores the list of current filters with the current one last
 128   *
 129   * @param string $tag The name of the filter hook.
 130   * @param mixed $value The value on which the filters hooked to <tt>$tag</tt> are applied on.
 131   * @param mixed $var,... Additional variables passed to the functions hooked to <tt>$tag</tt>.
 132   * @return mixed The filtered value after all hooked functions are applied to it.
 133   */
 134  function apply_filters($tag, $value) {
 135      global $wp_filter, $merged_filters, $wp_current_filter;
 136  
 137      $args = array();
 138  
 139      // Do 'all' actions first
 140      if ( isset($wp_filter['all']) ) {
 141          $wp_current_filter[] = $tag;
 142          $args = func_get_args();
 143          _wp_call_all_hook($args);
 144      }
 145  
 146      if ( !isset($wp_filter[$tag]) ) {
 147          if ( isset($wp_filter['all']) )
 148              array_pop($wp_current_filter);
 149          return $value;
 150      }
 151  
 152      if ( !isset($wp_filter['all']) )
 153          $wp_current_filter[] = $tag;
 154  
 155      // Sort
 156      if ( !isset( $merged_filters[ $tag ] ) ) {
 157          ksort($wp_filter[$tag]);
 158          $merged_filters[ $tag ] = true;
 159      }
 160  
 161      reset( $wp_filter[ $tag ] );
 162  
 163      if ( empty($args) )
 164          $args = func_get_args();
 165  
 166      do {
 167          foreach( (array) current($wp_filter[$tag]) as $the_ )
 168              if ( !is_null($the_['function']) ){
 169                  $args[1] = $value;
 170                  $value = call_user_func_array($the_['function'], array_slice($args, 1, (int) $the_['accepted_args']));
 171              }
 172  
 173      } while ( next($wp_filter[$tag]) !== false );
 174  
 175      array_pop( $wp_current_filter );
 176  
 177      return $value;
 178  }
 179  
 180  /**
 181   * Execute functions hooked on a specific filter hook, specifying arguments in an array.
 182   *
 183   * @see apply_filters() This function is identical, but the arguments passed to the
 184   * functions hooked to <tt>$tag</tt> are supplied using an array.
 185   *
 186   * @package WordPress
 187   * @subpackage Plugin
 188   * @since 3.0.0
 189   * @global array $wp_filter Stores all of the filters
 190   * @global array $merged_filters Merges the filter hooks using this function.
 191   * @global array $wp_current_filter stores the list of current filters with the current one last
 192   *
 193   * @param string $tag The name of the filter hook.
 194   * @param array $args The arguments supplied to the functions hooked to <tt>$tag</tt>
 195   * @return mixed The filtered value after all hooked functions are applied to it.
 196   */
 197  function apply_filters_ref_array($tag, $args) {
 198      global $wp_filter, $merged_filters, $wp_current_filter;
 199  
 200      // Do 'all' actions first
 201      if ( isset($wp_filter['all']) ) {
 202          $wp_current_filter[] = $tag;
 203          $all_args = func_get_args();
 204          _wp_call_all_hook($all_args);
 205      }
 206  
 207      if ( !isset($wp_filter[$tag]) ) {
 208          if ( isset($wp_filter['all']) )
 209              array_pop($wp_current_filter);
 210          return $args[0];
 211      }
 212  
 213      if ( !isset($wp_filter['all']) )
 214          $wp_current_filter[] = $tag;
 215  
 216      // Sort
 217      if ( !isset( $merged_filters[ $tag ] ) ) {
 218          ksort($wp_filter[$tag]);
 219          $merged_filters[ $tag ] = true;
 220      }
 221  
 222      reset( $wp_filter[ $tag ] );
 223  
 224      do {
 225          foreach( (array) current($wp_filter[$tag]) as $the_ )
 226              if ( !is_null($the_['function']) )
 227                  $args[0] = call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
 228  
 229      } while ( next($wp_filter[$tag]) !== false );
 230  
 231      array_pop( $wp_current_filter );
 232  
 233      return $args[0];
 234  }
 235  
 236  /**
 237   * Removes a function from a specified filter hook.
 238   *
 239   * This function removes a function attached to a specified filter hook. This
 240   * method can be used to remove default functions attached to a specific filter
 241   * hook and possibly replace them with a substitute.
 242   *
 243   * To remove a hook, the $function_to_remove and $priority arguments must match
 244   * when the hook was added. This goes for both filters and actions. No warning
 245   * will be given on removal failure.
 246   *
 247   * @package WordPress
 248   * @subpackage Plugin
 249   * @since 1.2
 250   *
 251   * @param string $tag The filter hook to which the function to be removed is hooked.
 252   * @param callback $function_to_remove The name of the function which should be removed.
 253   * @param int $priority optional. The priority of the function (default: 10).
 254   * @param int $accepted_args optional. The number of arguments the function accpets (default: 1).
 255   * @return boolean Whether the function existed before it was removed.
 256   */
 257  function remove_filter($tag, $function_to_remove, $priority = 10, $accepted_args = 1) {
 258      $function_to_remove = _wp_filter_build_unique_id($tag, $function_to_remove, $priority);
 259  
 260      $r = isset($GLOBALS['wp_filter'][$tag][$priority][$function_to_remove]);
 261  
 262      if ( true === $r) {
 263          unset($GLOBALS['wp_filter'][$tag][$priority][$function_to_remove]);
 264          if ( empty($GLOBALS['wp_filter'][$tag][$priority]) )
 265              unset($GLOBALS['wp_filter'][$tag][$priority]);
 266          unset($GLOBALS['merged_filters'][$tag]);
 267      }
 268  
 269      return $r;
 270  }
 271  
 272  /**
 273   * Remove all of the hooks from a filter.
 274   *
 275   * @since 2.7
 276   *
 277   * @param string $tag The filter to remove hooks from.
 278   * @param int $priority The priority number to remove.
 279   * @return bool True when finished.
 280   */
 281  function remove_all_filters($tag, $priority = false) {
 282      global $wp_filter, $merged_filters;
 283  
 284      if( isset($wp_filter[$tag]) ) {
 285          if( false !== $priority && isset($wp_filter[$tag][$priority]) )
 286              unset($wp_filter[$tag][$priority]);
 287          else
 288              unset($wp_filter[$tag]);
 289      }
 290  
 291      if( isset($merged_filters[$tag]) )
 292          unset($merged_filters[$tag]);
 293  
 294      return true;
 295  }
 296  
 297  /**
 298   * Retrieve the name of the current filter or action.
 299   *
 300   * @package WordPress
 301   * @subpackage Plugin
 302   * @since 2.5
 303   *
 304   * @return string Hook name of the current filter or action.
 305   */
 306  function current_filter() {
 307      global $wp_current_filter;
 308      return end( $wp_current_filter );
 309  }
 310  
 311  
 312  /**
 313   * Hooks a function on to a specific action.
 314   *
 315   * Actions are the hooks that the WordPress core launches at specific points
 316   * during execution, or when specific events occur. Plugins can specify that
 317   * one or more of its PHP functions are executed at these points, using the
 318   * Action API.
 319   *
 320   * @uses add_filter() Adds an action. Parameter list and functionality are the same.
 321   *
 322   * @package WordPress
 323   * @subpackage Plugin
 324   * @since 1.2
 325   *
 326   * @param string $tag The name of the action to which the $function_to_add is hooked.
 327   * @param callback $function_to_add The name of the function you wish to be called.
 328   * @param int $priority optional. Used to specify the order in which the functions associated with a particular action are executed (default: 10). Lower numbers correspond with earlier execution, and functions with the same priority are executed in the order in which they were added to the action.
 329   * @param int $accepted_args optional. The number of arguments the function accept (default 1).
 330   */
 331  function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
 332      return add_filter($tag, $function_to_add, $priority, $accepted_args);
 333  }
 334  
 335  
 336  /**
 337   * Execute functions hooked on a specific action hook.
 338   *
 339   * This function invokes all functions attached to action hook $tag. It is
 340   * possible to create new action hooks by simply calling this function,
 341   * specifying the name of the new hook using the <tt>$tag</tt> parameter.
 342   *
 343   * You can pass extra arguments to the hooks, much like you can with
 344   * apply_filters().
 345   *
 346   * @see apply_filters() This function works similar with the exception that
 347   * nothing is returned and only the functions or methods are called.
 348   *
 349   * @package WordPress
 350   * @subpackage Plugin
 351   * @since 1.2
 352   * @global array $wp_filter Stores all of the filters
 353   * @global array $wp_actions Increments the amount of times action was triggered.
 354   *
 355   * @param string $tag The name of the action to be executed.
 356   * @param mixed $arg,... Optional additional arguments which are passed on to the functions hooked to the action.
 357   * @return null Will return null if $tag does not exist in $wp_filter array
 358   */
 359  function do_action($tag, $arg = '') {
 360      global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
 361  
 362      if ( ! isset($wp_actions) )
 363          $wp_actions = array();
 364  
 365      if ( ! isset($wp_actions[$tag]) )
 366          $wp_actions[$tag] = 1;
 367      else
 368          ++$wp_actions[$tag];
 369  
 370      // Do 'all' actions first
 371      if ( isset($wp_filter['all']) ) {
 372          $wp_current_filter[] = $tag;
 373          $all_args = func_get_args();
 374          _wp_call_all_hook($all_args);
 375      }
 376  
 377      if ( !isset($wp_filter[$tag]) ) {
 378          if ( isset($wp_filter['all']) )
 379              array_pop($wp_current_filter);
 380          return;
 381      }
 382  
 383      if ( !isset($wp_filter['all']) )
 384          $wp_current_filter[] = $tag;
 385  
 386      $args = array();
 387      if ( is_array($arg) && 1 == count($arg) && isset($arg[0]) && is_object($arg[0]) ) // array(&$this)
 388          $args[] =& $arg[0];
 389      else
 390          $args[] = $arg;
 391      for ( $a = 2; $a < func_num_args(); $a++ )
 392          $args[] = func_get_arg($a);
 393  
 394      // Sort
 395      if ( !isset( $merged_filters[ $tag ] ) ) {
 396          ksort($wp_filter[$tag]);
 397          $merged_filters[ $tag ] = true;
 398      }
 399  
 400      reset( $wp_filter[ $tag ] );
 401  
 402      do {
 403          foreach ( (array) current($wp_filter[$tag]) as $the_ )
 404              if ( !is_null($the_['function']) )
 405                  call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
 406  
 407      } while ( next($wp_filter[$tag]) !== false );
 408  
 409      array_pop($wp_current_filter);
 410  }
 411  
 412  /**
 413   * Retrieve the number times an action is fired.
 414   *
 415   * @package WordPress
 416   * @subpackage Plugin
 417   * @since 2.1
 418   * @global array $wp_actions Increments the amount of times action was triggered.
 419   *
 420   * @param string $tag The name of the action hook.
 421   * @return int The number of times action hook <tt>$tag</tt> is fired
 422   */
 423  function did_action($tag) {
 424      global $wp_actions;
 425  
 426      if ( ! isset( $wp_actions ) || ! isset( $wp_actions[$tag] ) )
 427          return 0;
 428  
 429      return $wp_actions[$tag];
 430  }
 431  
 432  /**
 433   * Execute functions hooked on a specific action hook, specifying arguments in an array.
 434   *
 435   * @see do_action() This function is identical, but the arguments passed to the
 436   * functions hooked to <tt>$tag</tt> are supplied using an array.
 437   *
 438   * @package WordPress
 439   * @subpackage Plugin
 440   * @since 2.1
 441   * @global array $wp_filter Stores all of the filters
 442   * @global array $wp_actions Increments the amount of times action was triggered.
 443   *
 444   * @param string $tag The name of the action to be executed.
 445   * @param array $args The arguments supplied to the functions hooked to <tt>$tag</tt>
 446   * @return null Will return null if $tag does not exist in $wp_filter array
 447   */
 448  function do_action_ref_array($tag, $args) {
 449      global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
 450  
 451      if ( ! isset($wp_actions) )
 452          $wp_actions = array();
 453  
 454      if ( ! isset($wp_actions[$tag]) )
 455          $wp_actions[$tag] = 1;
 456      else
 457          ++$wp_actions[$tag];
 458  
 459      // Do 'all' actions first
 460      if ( isset($wp_filter['all']) ) {
 461          $wp_current_filter[] = $tag;
 462          $all_args = func_get_args();
 463          _wp_call_all_hook($all_args);
 464      }
 465  
 466      if ( !isset($wp_filter[$tag]) ) {
 467          if ( isset($wp_filter['all']) )
 468              array_pop($wp_current_filter);
 469          return;
 470      }
 471  
 472      if ( !isset($wp_filter['all']) )
 473          $wp_current_filter[] = $tag;
 474  
 475      // Sort
 476      if ( !isset( $merged_filters[ $tag ] ) ) {
 477          ksort($wp_filter[$tag]);
 478          $merged_filters[ $tag ] = true;
 479      }
 480  
 481      reset( $wp_filter[ $tag ] );
 482  
 483      do {
 484          foreach( (array) current($wp_filter[$tag]) as $the_ )
 485              if ( !is_null($the_['function']) )
 486                  call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
 487  
 488      } while ( next($wp_filter[$tag]) !== false );
 489  
 490      array_pop($wp_current_filter);
 491  }
 492  
 493  /**
 494   * Check if any action has been registered for a hook.
 495   *
 496   * @package WordPress
 497   * @subpackage Plugin
 498   * @since 2.5
 499   * @see has_filter() has_action() is an alias of has_filter().
 500   *
 501   * @param string $tag The name of the action hook.
 502   * @param callback $function_to_check optional.  If specified, return the priority of that function on this hook or false if not attached.
 503   * @return int|boolean Optionally returns the priority on that hook for the specified function.
 504   */
 505  function has_action($tag, $function_to_check = false) {
 506      return has_filter($tag, $function_to_check);
 507  }
 508  
 509  /**
 510   * Removes a function from a specified action hook.
 511   *
 512   * This function removes a function attached to a specified action hook. This
 513   * method can be used to remove default functions attached to a specific filter
 514   * hook and possibly replace them with a substitute.
 515   *
 516   * @package WordPress
 517   * @subpackage Plugin
 518   * @since 1.2
 519   *
 520   * @param string $tag The action hook to which the function to be removed is hooked.
 521   * @param callback $function_to_remove The name of the function which should be removed.
 522   * @param int $priority optional The priority of the function (default: 10).
 523   * @param int $accepted_args optional. The number of arguments the function accpets (default: 1).
 524   * @return boolean Whether the function is removed.
 525   */
 526  function remove_action($tag, $function_to_remove, $priority = 10, $accepted_args = 1) {
 527      return remove_filter($tag, $function_to_remove, $priority, $accepted_args);
 528  }
 529  
 530  /**
 531   * Remove all of the hooks from an action.
 532   *
 533   * @since 2.7
 534   *
 535   * @param string $tag The action to remove hooks from.
 536   * @param int $priority The priority number to remove them from.
 537   * @return bool True when finished.
 538   */
 539  function remove_all_actions($tag, $priority = false) {
 540      return remove_all_filters($tag, $priority);
 541  }
 542  
 543  //
 544  // Functions for handling plugins.
 545  //
 546  
 547  /**
 548   * Gets the basename of a plugin.
 549   *
 550   * This method extracts the name of a plugin from its filename.
 551   *
 552   * @package WordPress
 553   * @subpackage Plugin
 554   * @since 1.5
 555   *
 556   * @access private
 557   *
 558   * @param string $file The filename of plugin.
 559   * @return string The name of a plugin.
 560   * @uses WP_PLUGIN_DIR
 561   */
 562  function plugin_basename($file) {
 563      $file = str_replace('\\','/',$file); // sanitize for Win32 installs
 564      $file = preg_replace('|/+|','/', $file); // remove any duplicate slash
 565      $plugin_dir = str_replace('\\','/',WP_PLUGIN_DIR); // sanitize for Win32 installs
 566      $plugin_dir = preg_replace('|/+|','/', $plugin_dir); // remove any duplicate slash
 567      $mu_plugin_dir = str_replace('\\','/',WPMU_PLUGIN_DIR); // sanitize for Win32 installs
 568      $mu_plugin_dir = preg_replace('|/+|','/', $mu_plugin_dir); // remove any duplicate slash
 569      $file = preg_replace('#^' . preg_quote($plugin_dir, '#') . '/|^' . preg_quote($mu_plugin_dir, '#') . '/#','',$file); // get relative path from plugins dir
 570      $file = trim($file, '/');
 571      return $file;
 572  }
 573  
 574  /**
 575   * Gets the filesystem directory path (with trailing slash) for the plugin __FILE__ passed in
 576   * @package WordPress
 577   * @subpackage Plugin
 578   * @since 2.8
 579   *
 580   * @param string $file The filename of the plugin (__FILE__)
 581   * @return string the filesystem path of the directory that contains the plugin
 582   */
 583  function plugin_dir_path( $file ) {
 584      return trailingslashit( dirname( $file ) );
 585  }
 586  
 587  /**
 588   * Gets the URL directory path (with trailing slash) for the plugin __FILE__ passed in
 589   * @package WordPress
 590   * @subpackage Plugin
 591   * @since 2.8
 592   *
 593   * @param string $file The filename of the plugin (__FILE__)
 594   * @return string the URL path of the directory that contains the plugin
 595   */
 596  function plugin_dir_url( $file ) {
 597      return trailingslashit( plugins_url( '', $file ) );
 598  }
 599  
 600  /**
 601   * Set the activation hook for a plugin.
 602   *
 603   * When a plugin is activated, the action 'activate_PLUGINNAME' hook is
 604   * activated. In the name of this hook, PLUGINNAME is replaced with the name of
 605   * the plugin, including the optional subdirectory. For example, when the plugin
 606   * is located in wp-content/plugin/sampleplugin/sample.php, then the name of
 607   * this hook will become 'activate_sampleplugin/sample.php'. When the plugin
 608   * consists of only one file and is (as by default) located at
 609   * wp-content/plugin/sample.php the name of this hook will be
 610   * 'activate_sample.php'.
 611   *
 612   * @package WordPress
 613   * @subpackage Plugin
 614   * @since 2.0
 615   *
 616   * @param string $file The filename of the plugin including the path.
 617   * @param callback $function the function hooked to the 'activate_PLUGIN' action.
 618   */
 619  function register_activation_hook($file, $function) {
 620      $file = plugin_basename($file);
 621      add_action('activate_' . $file, $function);
 622  }
 623  
 624  /**
 625   * Set the deactivation hook for a plugin.
 626   *
 627   * When a plugin is deactivated, the action 'deactivate_PLUGINNAME' hook is
 628   * deactivated. In the name of this hook, PLUGINNAME is replaced with the name
 629   * of the plugin, including the optional subdirectory. For example, when the
 630   * plugin is located in wp-content/plugin/sampleplugin/sample.php, then
 631   * the name of this hook will become 'activate_sampleplugin/sample.php'.
 632   *
 633   * When the plugin consists of only one file and is (as by default) located at
 634   * wp-content/plugin/sample.php the name of this hook will be
 635   * 'activate_sample.php'.
 636   *
 637   * @package WordPress
 638   * @subpackage Plugin
 639   * @since 2.0
 640   *
 641   * @param string $file The filename of the plugin including the path.
 642   * @param callback $function the function hooked to the 'activate_PLUGIN' action.
 643   */
 644  function register_deactivation_hook($file, $function) {
 645      $file = plugin_basename($file);
 646      add_action('deactivate_' . $file, $function);
 647  }
 648  
 649  /**
 650   * Set the uninstallation hook for a plugin.
 651   *
 652   * Registers the uninstall hook that will be called when the user clicks on the
 653   * uninstall link that calls for the plugin to uninstall itself. The link won't
 654   * be active unless the plugin hooks into the action.
 655   *
 656   * The plugin should not run arbitrary code outside of functions, when
 657   * registering the uninstall hook. In order to run using the hook, the plugin
 658   * will have to be included, which means that any code laying outside of a
 659   * function will be run during the uninstall process. The plugin should not
 660   * hinder the uninstall process.
 661   *
 662   * If the plugin can not be written without running code within the plugin, then
 663   * the plugin should create a file named 'uninstall.php' in the base plugin
 664   * folder. This file will be called, if it exists, during the uninstall process
 665   * bypassing the uninstall hook. The plugin, when using the 'uninstall.php'
 666   * should always check for the 'WP_UNINSTALL_PLUGIN' constant, before
 667   * executing.
 668   *
 669   * @since 2.7
 670   *
 671   * @param string $file
 672   * @param callback $callback The callback to run when the hook is called. Must be a static method or function.
 673   */
 674  function register_uninstall_hook( $file, $callback ) {
 675      if ( is_array( $callback ) && is_object( $callback[0] ) ) {
 676          _doing_it_wrong( __FUNCTION__, __( 'Only a static class method or function can be used in an uninstall hook.' ), '3.1' );
 677          return;
 678      }
 679  
 680      // The option should not be autoloaded, because it is not needed in most
 681      // cases. Emphasis should be put on using the 'uninstall.php' way of
 682      // uninstalling the plugin.
 683      $uninstallable_plugins = (array) get_option('uninstall_plugins');
 684      $uninstallable_plugins[plugin_basename($file)] = $callback;
 685      update_option('uninstall_plugins', $uninstallable_plugins);
 686  }
 687  
 688  /**
 689   * Calls the 'all' hook, which will process the functions hooked into it.
 690   *
 691   * The 'all' hook passes all of the arguments or parameters that were used for
 692   * the hook, which this function was called for.
 693   *
 694   * This function is used internally for apply_filters(), do_action(), and
 695   * do_action_ref_array() and is not meant to be used from outside those
 696   * functions. This function does not check for the existence of the all hook, so
 697   * it will fail unless the all hook exists prior to this function call.
 698   *
 699   * @package WordPress
 700   * @subpackage Plugin
 701   * @since 2.5
 702   * @access private
 703   *
 704   * @uses $wp_filter Used to process all of the functions in the 'all' hook
 705   *
 706   * @param array $args The collected parameters from the hook that was called.
 707   * @param string $hook Optional. The hook name that was used to call the 'all' hook.
 708   */
 709  function _wp_call_all_hook($args) {
 710      global $wp_filter;
 711  
 712      reset( $wp_filter['all'] );
 713      do {
 714          foreach( (array) current($wp_filter['all']) as $the_ )
 715              if ( !is_null($the_['function']) )
 716                  call_user_func_array($the_['function'], $args);
 717  
 718      } while ( next($wp_filter['all']) !== false );
 719  }
 720  
 721  /**
 722   * Build Unique ID for storage and retrieval.
 723   *
 724   * The old way to serialize the callback caused issues and this function is the
 725   * solution. It works by checking for objects and creating an a new property in
 726   * the class to keep track of the object and new objects of the same class that
 727   * need to be added.
 728   *
 729   * It also allows for the removal of actions and filters for objects after they
 730   * change class properties. It is possible to include the property $wp_filter_id
 731   * in your class and set it to "null" or a number to bypass the workaround.
 732   * However this will prevent you from adding new classes and any new classes
 733   * will overwrite the previous hook by the same class.
 734   *
 735   * Functions and static method callbacks are just returned as strings and
 736   * shouldn't have any speed penalty.
 737   *
 738   * @package WordPress
 739   * @subpackage Plugin
 740   * @access private
 741   * @since 2.2.3
 742   * @link http://trac.wordpress.org/ticket/3875
 743   *
 744   * @global array $wp_filter Storage for all of the filters and actions
 745   * @param string $tag Used in counting how many hooks were applied
 746   * @param callback $function Used for creating unique id
 747   * @param int|bool $priority Used in counting how many hooks were applied.  If === false and $function is an object reference, we return the unique id only if it already has one, false otherwise.
 748   * @return string|bool Unique ID for usage as array key or false if $priority === false and $function is an object reference, and it does not already have a uniqe id.
 749   */
 750  function _wp_filter_build_unique_id($tag, $function, $priority) {
 751      global $wp_filter;
 752      static $filter_id_count = 0;
 753  
 754      if ( is_string($function) )
 755          return $function;
 756  
 757      if ( is_object($function) ) {
 758          // Closures are currently implemented as objects
 759          $function = array( $function, '' );
 760      } else {
 761          $function = (array) $function;
 762      }
 763  
 764      if (is_object($function[0]) ) {
 765          // Object Class Calling
 766          if ( function_exists('spl_object_hash') ) {
 767              return spl_object_hash($function[0]) . $function[1];
 768          } else {
 769              $obj_idx = get_class($function[0]).$function[1];
 770              if ( !isset($function[0]->wp_filter_id) ) {
 771                  if ( false === $priority )
 772                      return false;
 773                  $obj_idx .= isset($wp_filter[$tag][$priority]) ? count((array)$wp_filter[$tag][$priority]) : $filter_id_count;
 774                  $function[0]->wp_filter_id = $filter_id_count;
 775                  ++$filter_id_count;
 776              } else {
 777                  $obj_idx .= $function[0]->wp_filter_id;
 778              }
 779  
 780              return $obj_idx;
 781          }
 782      } else if ( is_string($function[0]) ) {
 783          // Static Calling
 784          return $function[0].$function[1];
 785      }
 786  }
 787  
 788  ?>