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class-wp-hook.php (15006B)

---

 <?php
 /**
  * Plugin API: WP_Hook class
  *
  * @package WordPress
  * @subpackage Plugin
  * @since 4.7.0
  */
 
 /**
  * Core class used to implement action and filter hook functionality.
  *
  * @since 4.7.0
  *
  * @see Iterator
  * @see ArrayAccess
  */
 final class WP_Hook implements Iterator, ArrayAccess {
 
 	/**
 	 * Hook callbacks.
 	 *
 	 * @since 4.7.0
 	 * @var array
 	 */
 	public $callbacks = array();
 
 	/**
 	 * The priority keys of actively running iterations of a hook.
 	 *
 	 * @since 4.7.0
 	 * @var array
 	 */
 	private $iterations = array();
 
 	/**
 	 * The current priority of actively running iterations of a hook.
 	 *
 	 * @since 4.7.0
 	 * @var array
 	 */
 	private $current_priority = array();
 
 	/**
 	 * Number of levels this hook can be recursively called.
 	 *
 	 * @since 4.7.0
 	 * @var int
 	 */
 	private $nesting_level = 0;
 
 	/**
 	 * Flag for if we're currently doing an action, rather than a filter.
 	 *
 	 * @since 4.7.0
 	 * @var bool
 	 */
 	private $doing_action = false;
 
 	/**
 	 * Adds a callback function to a filter hook.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @param string   $hook_name     The name of the filter to add the callback to.
 	 * @param callable $callback      The callback to be run when the filter is applied.
 	 * @param int      $priority      The order in which the functions associated with a particular filter
 	 *                                are executed. Lower numbers correspond with earlier execution,
 	 *                                and functions with the same priority are executed in the order
 	 *                                in which they were added to the filter.
 	 * @param int      $accepted_args The number of arguments the function accepts.
 	 */
 	public function add_filter( $hook_name, $callback, $priority, $accepted_args ) {
 		$idx = _wp_filter_build_unique_id( $hook_name, $callback, $priority );
 
 		$priority_existed = isset( $this->callbacks[ $priority ] );
 
 		$this->callbacks[ $priority ][ $idx ] = array(
 			'function'      => $callback,
 			'accepted_args' => $accepted_args,
 		);
 
 		// If we're adding a new priority to the list, put them back in sorted order.
 		if ( ! $priority_existed && count( $this->callbacks ) > 1 ) {
 			ksort( $this->callbacks, SORT_NUMERIC );
 		}
 
 		if ( $this->nesting_level > 0 ) {
 			$this->resort_active_iterations( $priority, $priority_existed );
 		}
 	}
 
 	/**
 	 * Handles resetting callback priority keys mid-iteration.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @param false|int $new_priority     Optional. The priority of the new filter being added. Default false,
 	 *                                    for no priority being added.
 	 * @param bool      $priority_existed Optional. Flag for whether the priority already existed before the new
 	 *                                    filter was added. Default false.
 	 */
 	private function resort_active_iterations( $new_priority = false, $priority_existed = false ) {
 		$new_priorities = array_keys( $this->callbacks );
 
 		// If there are no remaining hooks, clear out all running iterations.
 		if ( ! $new_priorities ) {
 			foreach ( $this->iterations as $index => $iteration ) {
 				$this->iterations[ $index ] = $new_priorities;
 			}
 
 			return;
 		}
 
 		$min = min( $new_priorities );
 
 		foreach ( $this->iterations as $index => &$iteration ) {
 			$current = current( $iteration );
 
 			// If we're already at the end of this iteration, just leave the array pointer where it is.
 			if ( false === $current ) {
 				continue;
 			}
 
 			$iteration = $new_priorities;
 
 			if ( $current < $min ) {
 				array_unshift( $iteration, $current );
 				continue;
 			}
 
 			while ( current( $iteration ) < $current ) {
 				if ( false === next( $iteration ) ) {
 					break;
 				}
 			}
 
 			// If we have a new priority that didn't exist, but ::apply_filters() or ::do_action() thinks it's the current priority...
 			if ( $new_priority === $this->current_priority[ $index ] && ! $priority_existed ) {
 				/*
 				 * ...and the new priority is the same as what $this->iterations thinks is the previous
 				 * priority, we need to move back to it.
 				 */
 
 				if ( false === current( $iteration ) ) {
 					// If we've already moved off the end of the array, go back to the last element.
 					$prev = end( $iteration );
 				} else {
 					// Otherwise, just go back to the previous element.
 					$prev = prev( $iteration );
 				}
 
 				if ( false === $prev ) {
 					// Start of the array. Reset, and go about our day.
 					reset( $iteration );
 				} elseif ( $new_priority !== $prev ) {
 					// Previous wasn't the same. Move forward again.
 					next( $iteration );
 				}
 			}
 		}
 
 		unset( $iteration );
 	}
 
 	/**
 	 * Removes a callback function from a filter hook.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @param string   $hook_name The filter hook to which the function to be removed is hooked.
 	 * @param callable $callback  The callback to be removed from running when the filter is applied.
 	 * @param int      $priority  The exact priority used when adding the original filter callback.
 	 * @return bool Whether the callback existed before it was removed.
 	 */
 	public function remove_filter( $hook_name, $callback, $priority ) {
 		$function_key = _wp_filter_build_unique_id( $hook_name, $callback, $priority );
 
 		$exists = isset( $this->callbacks[ $priority ][ $function_key ] );
 
 		if ( $exists ) {
 			unset( $this->callbacks[ $priority ][ $function_key ] );
 
 			if ( ! $this->callbacks[ $priority ] ) {
 				unset( $this->callbacks[ $priority ] );
 
 				if ( $this->nesting_level > 0 ) {
 					$this->resort_active_iterations();
 				}
 			}
 		}
 
 		return $exists;
 	}
 
 	/**
 	 * Checks if a specific callback has been registered for this hook.
 	 *
 	 * When using the `$callback` argument, this function may return a non-boolean value
 	 * that evaluates to false (e.g. 0), so use the `===` operator for testing the return value.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @param string         $hook_name Optional. The name of the filter hook. Default empty.
 	 * @param callable|false $callback  Optional. The callback to check for. Default false.
 	 * @return bool|int If `$callback` is omitted, returns boolean for whether the hook has
 	 *                  anything registered. When checking a specific function, the priority
 	 *                  of that hook is returned, or false if the function is not attached.
 	 */
 	public function has_filter( $hook_name = '', $callback = false ) {
 		if ( false === $callback ) {
 			return $this->has_filters();
 		}
 
 		$function_key = _wp_filter_build_unique_id( $hook_name, $callback, false );
 
 		if ( ! $function_key ) {
 			return false;
 		}
 
 		foreach ( $this->callbacks as $priority => $callbacks ) {
 			if ( isset( $callbacks[ $function_key ] ) ) {
 				return $priority;
 			}
 		}
 
 		return false;
 	}
 
 	/**
 	 * Checks if any callbacks have been registered for this hook.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @return bool True if callbacks have been registered for the current hook, otherwise false.
 	 */
 	public function has_filters() {
 		foreach ( $this->callbacks as $callbacks ) {
 			if ( $callbacks ) {
 				return true;
 			}
 		}
 
 		return false;
 	}
 
 	/**
 	 * Removes all callbacks from the current filter.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @param int|false $priority Optional. The priority number to remove. Default false.
 	 */
 	public function remove_all_filters( $priority = false ) {
 		if ( ! $this->callbacks ) {
 			return;
 		}
 
 		if ( false === $priority ) {
 			$this->callbacks = array();
 		} elseif ( isset( $this->callbacks[ $priority ] ) ) {
 			unset( $this->callbacks[ $priority ] );
 		}
 
 		if ( $this->nesting_level > 0 ) {
 			$this->resort_active_iterations();
 		}
 	}
 
 	/**
 	 * Calls the callback functions that have been added to a filter hook.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @param mixed $value The value to filter.
 	 * @param array $args  Additional parameters to pass to the callback functions.
 	 *                     This array is expected to include $value at index 0.
 	 * @return mixed The filtered value after all hooked functions are applied to it.
 	 */
 	public function apply_filters( $value, $args ) {
 		if ( ! $this->callbacks ) {
 			return $value;
 		}
 
 		$nesting_level = $this->nesting_level++;
 
 		$this->iterations[ $nesting_level ] = array_keys( $this->callbacks );
 		$num_args                           = count( $args );
 
 		do {
 			$this->current_priority[ $nesting_level ] = current( $this->iterations[ $nesting_level ] );
 			$priority                                 = $this->current_priority[ $nesting_level ];
 
 			foreach ( $this->callbacks[ $priority ] as $the_ ) {
 				if ( ! $this->doing_action ) {
 					$args[0] = $value;
 				}
 
 				// Avoid the array_slice() if possible.
 				if ( 0 == $the_['accepted_args'] ) {
 					$value = call_user_func( $the_['function'] );
 				} elseif ( $the_['accepted_args'] >= $num_args ) {
 					$value = call_user_func_array( $the_['function'], $args );
 				} else {
 					$value = call_user_func_array( $the_['function'], array_slice( $args, 0, (int) $the_['accepted_args'] ) );
 				}
 			}
 		} while ( false !== next( $this->iterations[ $nesting_level ] ) );
 
 		unset( $this->iterations[ $nesting_level ] );
 		unset( $this->current_priority[ $nesting_level ] );
 
 		$this->nesting_level--;
 
 		return $value;
 	}
 
 	/**
 	 * Calls the callback functions that have been added to an action hook.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @param array $args Parameters to pass to the callback functions.
 	 */
 	public function do_action( $args ) {
 		$this->doing_action = true;
 		$this->apply_filters( '', $args );
 
 		// If there are recursive calls to the current action, we haven't finished it until we get to the last one.
 		if ( ! $this->nesting_level ) {
 			$this->doing_action = false;
 		}
 	}
 
 	/**
 	 * Processes the functions hooked into the 'all' hook.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @param array $args Arguments to pass to the hook callbacks. Passed by reference.
 	 */
 	public function do_all_hook( &$args ) {
 		$nesting_level                      = $this->nesting_level++;
 		$this->iterations[ $nesting_level ] = array_keys( $this->callbacks );
 
 		do {
 			$priority = current( $this->iterations[ $nesting_level ] );
 
 			foreach ( $this->callbacks[ $priority ] as $the_ ) {
 				call_user_func_array( $the_['function'], $args );
 			}
 		} while ( false !== next( $this->iterations[ $nesting_level ] ) );
 
 		unset( $this->iterations[ $nesting_level ] );
 		$this->nesting_level--;
 	}
 
 	/**
 	 * Return the current priority level of the currently running iteration of the hook.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @return int|false If the hook is running, return the current priority level.
 	 *                   If it isn't running, return false.
 	 */
 	public function current_priority() {
 		if ( false === current( $this->iterations ) ) {
 			return false;
 		}
 
 		return current( current( $this->iterations ) );
 	}
 
 	/**
 	 * Normalizes filters set up before WordPress has initialized to WP_Hook objects.
 	 *
 	 * The `$filters` parameter should be an array keyed by hook name, with values
 	 * containing either:
 	 *
 	 *  - A `WP_Hook` instance
 	 *  - An array of callbacks keyed by their priorities
 	 *
 	 * Examples:
 	 *
 	 *     $filters = array(
 	 *         'wp_fatal_error_handler_enabled' => array(
 	 *             10 => array(
 	 *                 array(
 	 *                     'accepted_args' => 0,
 	 *                     'function'      => function() {
 	 *                         return false;
 	 *                     },
 	 *                 ),
 	 *             ),
 	 *         ),
 	 *     );
 	 *
 	 * @since 4.7.0
 	 *
 	 * @param array $filters Filters to normalize. See documentation above for details.
 	 * @return WP_Hook[] Array of normalized filters.
 	 */
 	public static function build_preinitialized_hooks( $filters ) {
 		/** @var WP_Hook[] $normalized */
 		$normalized = array();
 
 		foreach ( $filters as $hook_name => $callback_groups ) {
 			if ( is_object( $callback_groups ) && $callback_groups instanceof WP_Hook ) {
 				$normalized[ $hook_name ] = $callback_groups;
 				continue;
 			}
 
 			$hook = new WP_Hook();
 
 			// Loop through callback groups.
 			foreach ( $callback_groups as $priority => $callbacks ) {
 
 				// Loop through callbacks.
 				foreach ( $callbacks as $cb ) {
 					$hook->add_filter( $hook_name, $cb['function'], $priority, $cb['accepted_args'] );
 				}
 			}
 
 			$normalized[ $hook_name ] = $hook;
 		}
 
 		return $normalized;
 	}
 
 	/**
 	 * Determines whether an offset value exists.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @link https://www.php.net/manual/en/arrayaccess.offsetexists.php
 	 *
 	 * @param mixed $offset An offset to check for.
 	 * @return bool True if the offset exists, false otherwise.
 	 */
 	public function offsetExists( $offset ) {
 		return isset( $this->callbacks[ $offset ] );
 	}
 
 	/**
 	 * Retrieves a value at a specified offset.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @link https://www.php.net/manual/en/arrayaccess.offsetget.php
 	 *
 	 * @param mixed $offset The offset to retrieve.
 	 * @return mixed If set, the value at the specified offset, null otherwise.
 	 */
 	public function offsetGet( $offset ) {
 		return isset( $this->callbacks[ $offset ] ) ? $this->callbacks[ $offset ] : null;
 	}
 
 	/**
 	 * Sets a value at a specified offset.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @link https://www.php.net/manual/en/arrayaccess.offsetset.php
 	 *
 	 * @param mixed $offset The offset to assign the value to.
 	 * @param mixed $value The value to set.
 	 */
 	public function offsetSet( $offset, $value ) {
 		if ( is_null( $offset ) ) {
 			$this->callbacks[] = $value;
 		} else {
 			$this->callbacks[ $offset ] = $value;
 		}
 	}
 
 	/**
 	 * Unsets a specified offset.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @link https://www.php.net/manual/en/arrayaccess.offsetunset.php
 	 *
 	 * @param mixed $offset The offset to unset.
 	 */
 	public function offsetUnset( $offset ) {
 		unset( $this->callbacks[ $offset ] );
 	}
 
 	/**
 	 * Returns the current element.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @link https://www.php.net/manual/en/iterator.current.php
 	 *
 	 * @return array Of callbacks at current priority.
 	 */
 	public function current() {
 		return current( $this->callbacks );
 	}
 
 	/**
 	 * Moves forward to the next element.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @link https://www.php.net/manual/en/iterator.next.php
 	 *
 	 * @return array Of callbacks at next priority.
 	 */
 	public function next() {
 		return next( $this->callbacks );
 	}
 
 	/**
 	 * Returns the key of the current element.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @link https://www.php.net/manual/en/iterator.key.php
 	 *
 	 * @return mixed Returns current priority on success, or NULL on failure
 	 */
 	public function key() {
 		return key( $this->callbacks );
 	}
 
 	/**
 	 * Checks if current position is valid.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @link https://www.php.net/manual/en/iterator.valid.php
 	 *
 	 * @return bool Whether the current position is valid.
 	 */
 	public function valid() {
 		return key( $this->callbacks ) !== null;
 	}
 
 	/**
 	 * Rewinds the Iterator to the first element.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @link https://www.php.net/manual/en/iterator.rewind.php
 	 */
 	public function rewind() {
 		reset( $this->callbacks );
 	}
 
 }