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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 https://www.php.net/manual/en/language.pseudo-types.php#language.types.callback 'callback'}
  12   * type are valid.
  13   *
  14   * Also see the {@link https://developer.wordpress.org/plugins/ Plugin API} for
  15   * more information and examples on how to use a lot of these functions.
  16   *
  17   * This file should have no external dependencies.
  18   *
  19   * @package WordPress
  20   * @subpackage Plugin
  21   * @since 1.5.0
  22   */
  23  
  24  // Initialize the filter globals.
  25  require  __DIR__ . '/class-wp-hook.php';
  26  
  27  /** @var WP_Hook[] $wp_filter */
  28  global $wp_filter, $wp_actions, $wp_current_filter;
  29  
  30  if ( $wp_filter ) {
  31      $wp_filter = WP_Hook::build_preinitialized_hooks( $wp_filter );
  32  } else {
  33      $wp_filter = array();
  34  }
  35  
  36  if ( ! isset( $wp_actions ) ) {
  37      $wp_actions = array();
  38  }
  39  
  40  if ( ! isset( $wp_current_filter ) ) {
  41      $wp_current_filter = array();
  42  }
  43  
  44  /**
  45   * Hook a function or method to a specific filter action.
  46   *
  47   * WordPress offers filter hooks to allow plugins to modify
  48   * various types of internal data at runtime.
  49   *
  50   * A plugin can modify data by binding a callback to a filter hook. When the filter
  51   * is later applied, each bound callback is run in order of priority, and given
  52   * the opportunity to modify a value by returning a new value.
  53   *
  54   * The following example shows how a callback function is bound to a filter hook.
  55   *
  56   * Note that `$example` is passed to the callback, (maybe) modified, then returned:
  57   *
  58   *     function example_callback( $example ) {
  59   *         // Maybe modify $example in some way.
  60   *         return $example;
  61   *     }
  62   *     add_filter( 'example_filter', 'example_callback' );
  63   *
  64   * Bound callbacks can accept from none to the total number of arguments passed as parameters
  65   * in the corresponding apply_filters() call.
  66   *
  67   * In other words, if an apply_filters() call passes four total arguments, callbacks bound to
  68   * it can accept none (the same as 1) of the arguments or up to four. The important part is that
  69   * the `$accepted_args` value must reflect the number of arguments the bound callback *actually*
  70   * opted to accept. If no arguments were accepted by the callback that is considered to be the
  71   * same as accepting 1 argument. For example:
  72   *
  73   *     // Filter call.
  74   *     $value = apply_filters( 'hook', $value, $arg2, $arg3 );
  75   *
  76   *     // Accepting zero/one arguments.
  77   *     function example_callback() {
  78   *         ...
  79   *         return 'some value';
  80   *     }
  81   *     add_filter( 'hook', 'example_callback' ); // Where $priority is default 10, $accepted_args is default 1.
  82   *
  83   *     // Accepting two arguments (three possible).
  84   *     function example_callback( $value, $arg2 ) {
  85   *         ...
  86   *         return $maybe_modified_value;
  87   *     }
  88   *     add_filter( 'hook', 'example_callback', 10, 2 ); // Where $priority is 10, $accepted_args is 2.
  89   *
  90   * *Note:* The function will return true whether or not the callback is valid.
  91   * It is up to you to take care. This is done for optimization purposes, so
  92   * everything is as quick as possible.
  93   *
  94   * @since 0.71
  95   *
  96   * @global array $wp_filter A multidimensional array of all hooks and the callbacks hooked to them.
  97   *
  98   * @param string   $tag             The name of the filter to hook the $function_to_add callback to.
  99   * @param callable $function_to_add The callback to be run when the filter is applied.
 100   * @param int      $priority        Optional. Used to specify the order in which the functions
 101   *                                  associated with a particular action are executed.
 102   *                                  Lower numbers correspond with earlier execution,
 103   *                                  and functions with the same priority are executed
 104   *                                  in the order in which they were added to the action. Default 10.
 105   * @param int      $accepted_args   Optional. The number of arguments the function accepts. Default 1.
 106   * @return true
 107   */
 108  function add_filter( $tag, $function_to_add, $priority = 10, $accepted_args = 1 ) {
 109      global $wp_filter;
 110      if ( ! isset( $wp_filter[ $tag ] ) ) {
 111          $wp_filter[ $tag ] = new WP_Hook();
 112      }
 113      $wp_filter[ $tag ]->add_filter( $tag, $function_to_add, $priority, $accepted_args );
 114      return true;
 115  }
 116  
 117  /**
 118   * Check if any filter has been registered for a hook.
 119   *
 120   * @since 2.5.0
 121   *
 122   * @global array $wp_filter Stores all of the filters and actions.
 123   *
 124   * @param string        $tag               The name of the filter hook.
 125   * @param callable|bool $function_to_check Optional. The callback to check for. Default false.
 126   * @return false|int If $function_to_check is omitted, returns boolean for whether the hook has
 127   *                   anything registered. When checking a specific function, the priority of that
 128   *                   hook is returned, or false if the function is not attached. When using the
 129   *                   $function_to_check argument, this function may return a non-boolean value
 130   *                   that evaluates to false (e.g.) 0, so use the === operator for testing the
 131   *                   return value.
 132   */
 133  function has_filter( $tag, $function_to_check = false ) {
 134      global $wp_filter;
 135  
 136      if ( ! isset( $wp_filter[ $tag ] ) ) {
 137          return false;
 138      }
 139  
 140      return $wp_filter[ $tag ]->has_filter( $tag, $function_to_check );
 141  }
 142  
 143  /**
 144   * Calls the callback functions that have been added to a filter hook.
 145   *
 146   * The callback functions attached to the filter hook are invoked by calling
 147   * this function. This function can be used to create a new filter hook by
 148   * simply calling this function with the name of the new hook specified using
 149   * the `$tag` parameter.
 150   *
 151   * The function also allows for multiple additional arguments to be passed to hooks.
 152   *
 153   * Example usage:
 154   *
 155   *     // The filter callback function.
 156   *     function example_callback( $string, $arg1, $arg2 ) {
 157   *         // (maybe) modify $string.
 158   *         return $string;
 159   *     }
 160   *     add_filter( 'example_filter', 'example_callback', 10, 3 );
 161   *
 162   *     /*
 163   *      * Apply the filters by calling the 'example_callback()' function
 164   *      * that's hooked onto `example_filter` above.
 165   *      *
 166   *      * - 'example_filter' is the filter hook.
 167   *      * - 'filter me' is the value being filtered.
 168   *      * - $arg1 and $arg2 are the additional arguments passed to the callback.
 169   *     $value = apply_filters( 'example_filter', 'filter me', $arg1, $arg2 );
 170   *
 171   * @since 0.71
 172   *
 173   * @global array $wp_filter         Stores all of the filters and actions.
 174   * @global array $wp_current_filter Stores the list of current filters with the current one last.
 175   *
 176   * @param string $tag     The name of the filter hook.
 177   * @param mixed  $value   The value to filter.
 178   * @param mixed  ...$args Additional parameters to pass to the callback functions.
 179   * @return mixed The filtered value after all hooked functions are applied to it.
 180   */
 181  function apply_filters( $tag, $value ) {
 182      global $wp_filter, $wp_current_filter;
 183  
 184      $args = func_get_args();
 185  
 186      // Do 'all' actions first.
 187      if ( isset( $wp_filter['all'] ) ) {
 188          $wp_current_filter[] = $tag;
 189          _wp_call_all_hook( $args );
 190      }
 191  
 192      if ( ! isset( $wp_filter[ $tag ] ) ) {
 193          if ( isset( $wp_filter['all'] ) ) {
 194              array_pop( $wp_current_filter );
 195          }
 196          return $value;
 197      }
 198  
 199      if ( ! isset( $wp_filter['all'] ) ) {
 200          $wp_current_filter[] = $tag;
 201      }
 202  
 203      // Don't pass the tag name to WP_Hook.
 204      array_shift( $args );
 205  
 206      $filtered = $wp_filter[ $tag ]->apply_filters( $value, $args );
 207  
 208      array_pop( $wp_current_filter );
 209  
 210      return $filtered;
 211  }
 212  
 213  /**
 214   * Calls the callback functions that have been added to a filter hook, specifying arguments in an array.
 215   *
 216   * @since 3.0.0
 217   *
 218   * @see apply_filters() This function is identical, but the arguments passed to the
 219   * functions hooked to `$tag` are supplied using an array.
 220   *
 221   * @global array $wp_filter         Stores all of the filters and actions.
 222   * @global array $wp_current_filter Stores the list of current filters with the current one last.
 223   *
 224   * @param string $tag  The name of the filter hook.
 225   * @param array  $args The arguments supplied to the functions hooked to $tag.
 226   * @return mixed The filtered value after all hooked functions are applied to it.
 227   */
 228  function apply_filters_ref_array( $tag, $args ) {
 229      global $wp_filter, $wp_current_filter;
 230  
 231      // Do 'all' actions first.
 232      if ( isset( $wp_filter['all'] ) ) {
 233          $wp_current_filter[] = $tag;
 234          $all_args            = func_get_args();
 235          _wp_call_all_hook( $all_args );
 236      }
 237  
 238      if ( ! isset( $wp_filter[ $tag ] ) ) {
 239          if ( isset( $wp_filter['all'] ) ) {
 240              array_pop( $wp_current_filter );
 241          }
 242          return $args[0];
 243      }
 244  
 245      if ( ! isset( $wp_filter['all'] ) ) {
 246          $wp_current_filter[] = $tag;
 247      }
 248  
 249      $filtered = $wp_filter[ $tag ]->apply_filters( $args[0], $args );
 250  
 251      array_pop( $wp_current_filter );
 252  
 253      return $filtered;
 254  }
 255  
 256  /**
 257   * Removes a function from a specified filter hook.
 258   *
 259   * This function removes a function attached to a specified filter hook. This
 260   * method can be used to remove default functions attached to a specific filter
 261   * hook and possibly replace them with a substitute.
 262   *
 263   * To remove a hook, the $function_to_remove and $priority arguments must match
 264   * when the hook was added. This goes for both filters and actions. No warning
 265   * will be given on removal failure.
 266   *
 267   * @since 1.2.0
 268   *
 269   * @global array $wp_filter Stores all of the filters and actions.
 270   *
 271   * @param string   $tag                The filter hook to which the function to be removed is hooked.
 272   * @param callable $function_to_remove The name of the function which should be removed.
 273   * @param int      $priority           Optional. The priority of the function. Default 10.
 274   * @return bool    Whether the function existed before it was removed.
 275   */
 276  function remove_filter( $tag, $function_to_remove, $priority = 10 ) {
 277      global $wp_filter;
 278  
 279      $r = false;
 280      if ( isset( $wp_filter[ $tag ] ) ) {
 281          $r = $wp_filter[ $tag ]->remove_filter( $tag, $function_to_remove, $priority );
 282          if ( ! $wp_filter[ $tag ]->callbacks ) {
 283              unset( $wp_filter[ $tag ] );
 284          }
 285      }
 286  
 287      return $r;
 288  }
 289  
 290  /**
 291   * Remove all of the hooks from a filter.
 292   *
 293   * @since 2.7.0
 294   *
 295   * @global array $wp_filter Stores all of the filters and actions.
 296   *
 297   * @param string   $tag      The filter to remove hooks from.
 298   * @param int|bool $priority Optional. The priority number to remove. Default false.
 299   * @return true True when finished.
 300   */
 301  function remove_all_filters( $tag, $priority = false ) {
 302      global $wp_filter;
 303  
 304      if ( isset( $wp_filter[ $tag ] ) ) {
 305          $wp_filter[ $tag ]->remove_all_filters( $priority );
 306          if ( ! $wp_filter[ $tag ]->has_filters() ) {
 307              unset( $wp_filter[ $tag ] );
 308          }
 309      }
 310  
 311      return true;
 312  }
 313  
 314  /**
 315   * Retrieve the name of the current filter or action.
 316   *
 317   * @since 2.5.0
 318   *
 319   * @global array $wp_current_filter Stores the list of current filters with the current one last
 320   *
 321   * @return string Hook name of the current filter or action.
 322   */
 323  function current_filter() {
 324      global $wp_current_filter;
 325      return end( $wp_current_filter );
 326  }
 327  
 328  /**
 329   * Retrieve the name of the current action.
 330   *
 331   * @since 3.9.0
 332   *
 333   * @return string Hook name of the current action.
 334   */
 335  function current_action() {
 336      return current_filter();
 337  }
 338  
 339  /**
 340   * Retrieve the name of a filter currently being processed.
 341   *
 342   * The function current_filter() only returns the most recent filter or action
 343   * being executed. did_action() returns true once the action is initially
 344   * processed.
 345   *
 346   * This function allows detection for any filter currently being
 347   * executed (despite not being the most recent filter to fire, in the case of
 348   * hooks called from hook callbacks) to be verified.
 349   *
 350   * @since 3.9.0
 351   *
 352   * @see current_filter()
 353   * @see did_action()
 354   * @global array $wp_current_filter Current filter.
 355   *
 356   * @param null|string $filter Optional. Filter to check. Defaults to null, which
 357   *                            checks if any filter is currently being run.
 358   * @return bool Whether the filter is currently in the stack.
 359   */
 360  function doing_filter( $filter = null ) {
 361      global $wp_current_filter;
 362  
 363      if ( null === $filter ) {
 364          return ! empty( $wp_current_filter );
 365      }
 366  
 367      return in_array( $filter, $wp_current_filter );
 368  }
 369  
 370  /**
 371   * Retrieve the name of an action currently being processed.
 372   *
 373   * @since 3.9.0
 374   *
 375   * @param string|null $action Optional. Action to check. Defaults to null, which checks
 376   *                            if any action is currently being run.
 377   * @return bool Whether the action is currently in the stack.
 378   */
 379  function doing_action( $action = null ) {
 380      return doing_filter( $action );
 381  }
 382  
 383  /**
 384   * Hooks a function on to a specific action.
 385   *
 386   * Actions are the hooks that the WordPress core launches at specific points
 387   * during execution, or when specific events occur. Plugins can specify that
 388   * one or more of its PHP functions are executed at these points, using the
 389   * Action API.
 390   *
 391   * @since 1.2.0
 392   *
 393   * @param string   $tag             The name of the action to which the $function_to_add is hooked.
 394   * @param callable $function_to_add The name of the function you wish to be called.
 395   * @param int      $priority        Optional. Used to specify the order in which the functions
 396   *                                  associated with a particular action are executed. Default 10.
 397   *                                  Lower numbers correspond with earlier execution,
 398   *                                  and functions with the same priority are executed
 399   *                                  in the order in which they were added to the action.
 400   * @param int      $accepted_args   Optional. The number of arguments the function accepts. Default 1.
 401   * @return true Will always return true.
 402   */
 403  function add_action( $tag, $function_to_add, $priority = 10, $accepted_args = 1 ) {
 404      return add_filter( $tag, $function_to_add, $priority, $accepted_args );
 405  }
 406  
 407  /**
 408   * Execute functions hooked on a specific action hook.
 409   *
 410   * This function invokes all functions attached to action hook `$tag`. It is
 411   * possible to create new action hooks by simply calling this function,
 412   * specifying the name of the new hook using the `$tag` parameter.
 413   *
 414   * You can pass extra arguments to the hooks, much like you can with `apply_filters()`.
 415   *
 416   * Example usage:
 417   *
 418   *     // The action callback function.
 419   *     function example_callback( $arg1, $arg2 ) {
 420   *         // (maybe) do something with the args.
 421   *     }
 422   *     add_action( 'example_action', 'example_callback', 10, 2 );
 423   *
 424   *     /*
 425   *      * Trigger the actions by calling the 'example_callback()' function
 426   *      * that's hooked onto `example_action` above.
 427   *      *
 428   *      * - 'example_action' is the action hook.
 429   *      * - $arg1 and $arg2 are the additional arguments passed to the callback.
 430   *     $value = do_action( 'example_action', $arg1, $arg2 );
 431   *
 432   * @since 1.2.0
 433   * @since 5.3.0 Formalized the existing and already documented `...$arg` parameter
 434   *              by adding it to the function signature.
 435   *
 436   * @global array $wp_filter         Stores all of the filters and actions.
 437   * @global array $wp_actions        Increments the amount of times action was triggered.
 438   * @global array $wp_current_filter Stores the list of current filters with the current one last.
 439   *
 440   * @param string $tag    The name of the action to be executed.
 441   * @param mixed  ...$arg Optional. Additional arguments which are passed on to the
 442   *                       functions hooked to the action. Default empty.
 443   */
 444  function do_action( $tag, ...$arg ) {
 445      global $wp_filter, $wp_actions, $wp_current_filter;
 446  
 447      if ( ! isset( $wp_actions[ $tag ] ) ) {
 448          $wp_actions[ $tag ] = 1;
 449      } else {
 450          ++$wp_actions[ $tag ];
 451      }
 452  
 453      // Do 'all' actions first.
 454      if ( isset( $wp_filter['all'] ) ) {
 455          $wp_current_filter[] = $tag;
 456          $all_args            = func_get_args();
 457          _wp_call_all_hook( $all_args );
 458      }
 459  
 460      if ( ! isset( $wp_filter[ $tag ] ) ) {
 461          if ( isset( $wp_filter['all'] ) ) {
 462              array_pop( $wp_current_filter );
 463          }
 464          return;
 465      }
 466  
 467      if ( ! isset( $wp_filter['all'] ) ) {
 468          $wp_current_filter[] = $tag;
 469      }
 470  
 471      if ( empty( $arg ) ) {
 472          $arg[] = '';
 473      } elseif ( is_array( $arg[0] ) && 1 === count( $arg[0] ) && isset( $arg[0][0] ) && is_object( $arg[0][0] ) ) {
 474          // Backward compatibility for PHP4-style passing of `array( &$this )` as action `$arg`.
 475          $arg[0] = $arg[0][0];
 476      }
 477  
 478      $wp_filter[ $tag ]->do_action( $arg );
 479  
 480      array_pop( $wp_current_filter );
 481  }
 482  
 483  /**
 484   * Retrieve the number of times an action is fired.
 485   *
 486   * @since 2.1.0
 487   *
 488   * @global array $wp_actions Increments the amount of times action was triggered.
 489   *
 490   * @param string $tag The name of the action hook.
 491   * @return int The number of times action hook $tag is fired.
 492   */
 493  function did_action( $tag ) {
 494      global $wp_actions;
 495  
 496      if ( ! isset( $wp_actions[ $tag ] ) ) {
 497          return 0;
 498      }
 499  
 500      return $wp_actions[ $tag ];
 501  }
 502  
 503  /**
 504   * Calls the callback functions that have been added to an action hook, specifying arguments in an array.
 505   *
 506   * @since 2.1.0
 507   *
 508   * @see do_action() This function is identical, but the arguments passed to the
 509   *                  functions hooked to `$tag` are supplied using an array.
 510   * @global array $wp_filter         Stores all of the filters and actions.
 511   * @global array $wp_actions        Increments the amount of times action was triggered.
 512   * @global array $wp_current_filter Stores the list of current filters with the current one last.
 513   *
 514   * @param string $tag  The name of the action to be executed.
 515   * @param array  $args The arguments supplied to the functions hooked to `$tag`.
 516   */
 517  function do_action_ref_array( $tag, $args ) {
 518      global $wp_filter, $wp_actions, $wp_current_filter;
 519  
 520      if ( ! isset( $wp_actions[ $tag ] ) ) {
 521          $wp_actions[ $tag ] = 1;
 522      } else {
 523          ++$wp_actions[ $tag ];
 524      }
 525  
 526      // Do 'all' actions first.
 527      if ( isset( $wp_filter['all'] ) ) {
 528          $wp_current_filter[] = $tag;
 529          $all_args            = func_get_args();
 530          _wp_call_all_hook( $all_args );
 531      }
 532  
 533      if ( ! isset( $wp_filter[ $tag ] ) ) {
 534          if ( isset( $wp_filter['all'] ) ) {
 535              array_pop( $wp_current_filter );
 536          }
 537          return;
 538      }
 539  
 540      if ( ! isset( $wp_filter['all'] ) ) {
 541          $wp_current_filter[] = $tag;
 542      }
 543  
 544      $wp_filter[ $tag ]->do_action( $args );
 545  
 546      array_pop( $wp_current_filter );
 547  }
 548  
 549  /**
 550   * Check if any action has been registered for a hook.
 551   *
 552   * @since 2.5.0
 553   *
 554   * @see has_filter() has_action() is an alias of has_filter().
 555   *
 556   * @param string        $tag               The name of the action hook.
 557   * @param callable|bool $function_to_check Optional. The callback to check for. Default false.
 558   * @return bool|int If $function_to_check is omitted, returns boolean for whether the hook has
 559   *                  anything registered. When checking a specific function, the priority of that
 560   *                  hook is returned, or false if the function is not attached. When using the
 561   *                  $function_to_check argument, this function may return a non-boolean value
 562   *                  that evaluates to false (e.g.) 0, so use the === operator for testing the
 563   *                  return value.
 564   */
 565  function has_action( $tag, $function_to_check = false ) {
 566      return has_filter( $tag, $function_to_check );
 567  }
 568  
 569  /**
 570   * Removes a function from a specified action hook.
 571   *
 572   * This function removes a function attached to a specified action hook. This
 573   * method can be used to remove default functions attached to a specific filter
 574   * hook and possibly replace them with a substitute.
 575   *
 576   * @since 1.2.0
 577   *
 578   * @param string   $tag                The action hook to which the function to be removed is hooked.
 579   * @param callable $function_to_remove The name of the function which should be removed.
 580   * @param int      $priority           Optional. The priority of the function. Default 10.
 581   * @return bool Whether the function is removed.
 582   */
 583  function remove_action( $tag, $function_to_remove, $priority = 10 ) {
 584      return remove_filter( $tag, $function_to_remove, $priority );
 585  }
 586  
 587  /**
 588   * Remove all of the hooks from an action.
 589   *
 590   * @since 2.7.0
 591   *
 592   * @param string   $tag      The action to remove hooks from.
 593   * @param int|bool $priority The priority number to remove them from. Default false.
 594   * @return true True when finished.
 595   */
 596  function remove_all_actions( $tag, $priority = false ) {
 597      return remove_all_filters( $tag, $priority );
 598  }
 599  
 600  /**
 601   * Fires functions attached to a deprecated filter hook.
 602   *
 603   * When a filter hook is deprecated, the apply_filters() call is replaced with
 604   * apply_filters_deprecated(), which triggers a deprecation notice and then fires
 605   * the original filter hook.
 606   *
 607   * Note: the value and extra arguments passed to the original apply_filters() call
 608   * must be passed here to `$args` as an array. For example:
 609   *
 610   *     // Old filter.
 611   *     return apply_filters( 'wpdocs_filter', $value, $extra_arg );
 612   *
 613   *     // Deprecated.
 614   *     return apply_filters_deprecated( 'wpdocs_filter', array( $value, $extra_arg ), '4.9.0', 'wpdocs_new_filter' );
 615   *
 616   * @since 4.6.0
 617   *
 618   * @see _deprecated_hook()
 619   *
 620   * @param string $tag         The name of the filter hook.
 621   * @param array  $args        Array of additional function arguments to be passed to apply_filters().
 622   * @param string $version     The version of WordPress that deprecated the hook.
 623   * @param string $replacement Optional. The hook that should have been used. Default null.
 624   * @param string $message     Optional. A message regarding the change. Default null.
 625   */
 626  function apply_filters_deprecated( $tag, $args, $version, $replacement = null, $message = null ) {
 627      if ( ! has_filter( $tag ) ) {
 628          return $args[0];
 629      }
 630  
 631      _deprecated_hook( $tag, $version, $replacement, $message );
 632  
 633      return apply_filters_ref_array( $tag, $args );
 634  }
 635  
 636  /**
 637   * Fires functions attached to a deprecated action hook.
 638   *
 639   * When an action hook is deprecated, the do_action() call is replaced with
 640   * do_action_deprecated(), which triggers a deprecation notice and then fires
 641   * the original hook.
 642   *
 643   * @since 4.6.0
 644   *
 645   * @see _deprecated_hook()
 646   *
 647   * @param string $tag         The name of the action hook.
 648   * @param array  $args        Array of additional function arguments to be passed to do_action().
 649   * @param string $version     The version of WordPress that deprecated the hook.
 650   * @param string $replacement Optional. The hook that should have been used. Default null.
 651   * @param string $message     Optional. A message regarding the change. Default null.
 652   */
 653  function do_action_deprecated( $tag, $args, $version, $replacement = null, $message = null ) {
 654      if ( ! has_action( $tag ) ) {
 655          return;
 656      }
 657  
 658      _deprecated_hook( $tag, $version, $replacement, $message );
 659  
 660      do_action_ref_array( $tag, $args );
 661  }
 662  
 663  //
 664  // Functions for handling plugins.
 665  //
 666  
 667  /**
 668   * Gets the basename of a plugin.
 669   *
 670   * This method extracts the name of a plugin from its filename.
 671   *
 672   * @since 1.5.0
 673   *
 674   * @global array $wp_plugin_paths
 675   *
 676   * @param string $file The filename of plugin.
 677   * @return string The name of a plugin.
 678   */
 679  function plugin_basename( $file ) {
 680      global $wp_plugin_paths;
 681  
 682      // $wp_plugin_paths contains normalized paths.
 683      $file = wp_normalize_path( $file );
 684  
 685      arsort( $wp_plugin_paths );
 686      foreach ( $wp_plugin_paths as $dir => $realdir ) {
 687          if ( strpos( $file, $realdir ) === 0 ) {
 688              $file = $dir . substr( $file, strlen( $realdir ) );
 689          }
 690      }
 691  
 692      $plugin_dir    = wp_normalize_path( WP_PLUGIN_DIR );
 693      $mu_plugin_dir = wp_normalize_path( WPMU_PLUGIN_DIR );
 694  
 695      // Get relative path from plugins directory.
 696      $file = preg_replace( '#^' . preg_quote( $plugin_dir, '#' ) . '/|^' . preg_quote( $mu_plugin_dir, '#' ) . '/#', '', $file );
 697      $file = trim( $file, '/' );
 698      return $file;
 699  }
 700  
 701  /**
 702   * Register a plugin's real path.
 703   *
 704   * This is used in plugin_basename() to resolve symlinked paths.
 705   *
 706   * @since 3.9.0
 707   *
 708   * @see wp_normalize_path()
 709   *
 710   * @global array $wp_plugin_paths
 711   *
 712   * @staticvar string $wp_plugin_path
 713   * @staticvar string $wpmu_plugin_path
 714   *
 715   * @param string $file Known path to the file.
 716   * @return bool Whether the path was able to be registered.
 717   */
 718  function wp_register_plugin_realpath( $file ) {
 719      global $wp_plugin_paths;
 720  
 721      // Normalize, but store as static to avoid recalculation of a constant value.
 722      static $wp_plugin_path = null, $wpmu_plugin_path = null;
 723      if ( ! isset( $wp_plugin_path ) ) {
 724          $wp_plugin_path   = wp_normalize_path( WP_PLUGIN_DIR );
 725          $wpmu_plugin_path = wp_normalize_path( WPMU_PLUGIN_DIR );
 726      }
 727  
 728      $plugin_path     = wp_normalize_path( dirname( $file ) );
 729      $plugin_realpath = wp_normalize_path( dirname( realpath( $file ) ) );
 730  
 731      if ( $plugin_path === $wp_plugin_path || $plugin_path === $wpmu_plugin_path ) {
 732          return false;
 733      }
 734  
 735      if ( $plugin_path !== $plugin_realpath ) {
 736          $wp_plugin_paths[ $plugin_path ] = $plugin_realpath;
 737      }
 738  
 739      return true;
 740  }
 741  
 742  /**
 743   * Get the filesystem directory path (with trailing slash) for the plugin __FILE__ passed in.
 744   *
 745   * @since 2.8.0
 746   *
 747   * @param string $file The filename of the plugin (__FILE__).
 748   * @return string the filesystem path of the directory that contains the plugin.
 749   */
 750  function plugin_dir_path( $file ) {
 751      return trailingslashit( dirname( $file ) );
 752  }
 753  
 754  /**
 755   * Get the URL directory path (with trailing slash) for the plugin __FILE__ passed in.
 756   *
 757   * @since 2.8.0
 758   *
 759   * @param string $file The filename of the plugin (__FILE__).
 760   * @return string the URL path of the directory that contains the plugin.
 761   */
 762  function plugin_dir_url( $file ) {
 763      return trailingslashit( plugins_url( '', $file ) );
 764  }
 765  
 766  /**
 767   * Set the activation hook for a plugin.
 768   *
 769   * When a plugin is activated, the action 'activate_PLUGINNAME' hook is
 770   * called. In the name of this hook, PLUGINNAME is replaced with the name
 771   * of the plugin, including the optional subdirectory. For example, when the
 772   * plugin is located in wp-content/plugins/sampleplugin/sample.php, then
 773   * the name of this hook will become 'activate_sampleplugin/sample.php'.
 774   *
 775   * When the plugin consists of only one file and is (as by default) located at
 776   * wp-content/plugins/sample.php the name of this hook will be
 777   * 'activate_sample.php'.
 778   *
 779   * @since 2.0.0
 780   *
 781   * @param string   $file     The filename of the plugin including the path.
 782   * @param callable $function The function hooked to the 'activate_PLUGIN' action.
 783   */
 784  function register_activation_hook( $file, $function ) {
 785      $file = plugin_basename( $file );
 786      add_action( 'activate_' . $file, $function );
 787  }
 788  
 789  /**
 790   * Set the deactivation hook for a plugin.
 791   *
 792   * When a plugin is deactivated, the action 'deactivate_PLUGINNAME' hook is
 793   * called. In the name of this hook, PLUGINNAME is replaced with the name
 794   * of the plugin, including the optional subdirectory. For example, when the
 795   * plugin is located in wp-content/plugins/sampleplugin/sample.php, then
 796   * the name of this hook will become 'deactivate_sampleplugin/sample.php'.
 797   *
 798   * When the plugin consists of only one file and is (as by default) located at
 799   * wp-content/plugins/sample.php the name of this hook will be
 800   * 'deactivate_sample.php'.
 801   *
 802   * @since 2.0.0
 803   *
 804   * @param string   $file     The filename of the plugin including the path.
 805   * @param callable $function The function hooked to the 'deactivate_PLUGIN' action.
 806   */
 807  function register_deactivation_hook( $file, $function ) {
 808      $file = plugin_basename( $file );
 809      add_action( 'deactivate_' . $file, $function );
 810  }
 811  
 812  /**
 813   * Set the uninstallation hook for a plugin.
 814   *
 815   * Registers the uninstall hook that will be called when the user clicks on the
 816   * uninstall link that calls for the plugin to uninstall itself. The link won't
 817   * be active unless the plugin hooks into the action.
 818   *
 819   * The plugin should not run arbitrary code outside of functions, when
 820   * registering the uninstall hook. In order to run using the hook, the plugin
 821   * will have to be included, which means that any code laying outside of a
 822   * function will be run during the uninstallation process. The plugin should not
 823   * hinder the uninstallation process.
 824   *
 825   * If the plugin can not be written without running code within the plugin, then
 826   * the plugin should create a file named 'uninstall.php' in the base plugin
 827   * folder. This file will be called, if it exists, during the uninstallation process
 828   * bypassing the uninstall hook. The plugin, when using the 'uninstall.php'
 829   * should always check for the 'WP_UNINSTALL_PLUGIN' constant, before
 830   * executing.
 831   *
 832   * @since 2.7.0
 833   *
 834   * @param string   $file     Plugin file.
 835   * @param callable $callback The callback to run when the hook is called. Must be
 836   *                           a static method or function.
 837   */
 838  function register_uninstall_hook( $file, $callback ) {
 839      if ( is_array( $callback ) && is_object( $callback[0] ) ) {
 840          _doing_it_wrong( __FUNCTION__, __( 'Only a static class method or function can be used in an uninstall hook.' ), '3.1.0' );
 841          return;
 842      }
 843  
 844      /*
 845       * The option should not be autoloaded, because it is not needed in most
 846       * cases. Emphasis should be put on using the 'uninstall.php' way of
 847       * uninstalling the plugin.
 848       */
 849      $uninstallable_plugins = (array) get_option( 'uninstall_plugins' );
 850      $plugin_basename       = plugin_basename( $file );
 851      if ( ! isset( $uninstallable_plugins[ $plugin_basename ] ) || $uninstallable_plugins[ $plugin_basename ] !== $callback ) {
 852          $uninstallable_plugins[ $plugin_basename ] = $callback;
 853          update_option( 'uninstall_plugins', $uninstallable_plugins );
 854      }
 855  }
 856  
 857  /**
 858   * Call the 'all' hook, which will process the functions hooked into it.
 859   *
 860   * The 'all' hook passes all of the arguments or parameters that were used for
 861   * the hook, which this function was called for.
 862   *
 863   * This function is used internally for apply_filters(), do_action(), and
 864   * do_action_ref_array() and is not meant to be used from outside those
 865   * functions. This function does not check for the existence of the all hook, so
 866   * it will fail unless the all hook exists prior to this function call.
 867   *
 868   * @since 2.5.0
 869   * @access private
 870   *
 871   * @global array $wp_filter Stores all of the filters and actions.
 872   *
 873   * @param array $args The collected parameters from the hook that was called.
 874   */
 875  function _wp_call_all_hook( $args ) {
 876      global $wp_filter;
 877  
 878      $wp_filter['all']->do_all_hook( $args );
 879  }
 880  
 881  /**
 882   * Build Unique ID for storage and retrieval.
 883   *
 884   * The old way to serialize the callback caused issues and this function is the
 885   * solution. It works by checking for objects and creating a new property in
 886   * the class to keep track of the object and new objects of the same class that
 887   * need to be added.
 888   *
 889   * It also allows for the removal of actions and filters for objects after they
 890   * change class properties. It is possible to include the property $wp_filter_id
 891   * in your class and set it to "null" or a number to bypass the workaround.
 892   * However this will prevent you from adding new classes and any new classes
 893   * will overwrite the previous hook by the same class.
 894   *
 895   * Functions and static method callbacks are just returned as strings and
 896   * shouldn't have any speed penalty.
 897   *
 898   * @link https://core.trac.wordpress.org/ticket/3875
 899   *
 900   * @since 2.2.3
 901   * @since 5.3.0 Removed workarounds for spl_object_hash().
 902   *              `$tag` and `$priority` are no longer used,
 903   *              and the function always returns a string.
 904   * @access private
 905   *
 906   * @param string   $tag      Unused. The name of the filter to build ID for.
 907   * @param callable $function The function to generate ID for.
 908   * @param int      $priority Unused. The order in which the functions
 909   *                           associated with a particular action are executed.
 910   * @return string Unique function ID for usage as array key.
 911   */
 912  function _wp_filter_build_unique_id( $tag, $function, $priority ) {
 913      if ( is_string( $function ) ) {
 914          return $function;
 915      }
 916  
 917      if ( is_object( $function ) ) {
 918          // Closures are currently implemented as objects.
 919          $function = array( $function, '' );
 920      } else {
 921          $function = (array) $function;
 922      }
 923  
 924      if ( is_object( $function[0] ) ) {
 925          // Object class calling.
 926          return spl_object_hash( $function[0] ) . $function[1];
 927      } elseif ( is_string( $function[0] ) ) {
 928          // Static calling.
 929          return $function[0] . '::' . $function[1];
 930      }
 931  }