<?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 */ #[AllowDynamicProperties] final class WP_Hook implements Iterator, ArrayAccess { /** * Hook callbacks. * * @since 4.7.0 * @var array */ public $callbacks = array(); /** * Priorities list. * * @since 6.4.0 * @var array */ protected $priorities = 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 ) { if ( null === $priority ) { $priority = 0; } $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' => (int) $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 ); } $this->priorities = array_keys( $this->callbacks ); 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 = $this->priorities; // 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|string|array $callback The callback to be removed from running when the filter is applied. * This method can be called unconditionally to speculatively remove * a callback that may or may not exist. * @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 ) { if ( null === $priority ) { $priority = 0; } $function_key = _wp_filter_build_unique_id( $hook_name, $callback, $priority ); $exists = isset( $function_key, $this->callbacks[ $priority ][ $function_key ] ); if ( $exists ) { unset( $this->callbacks[ $priority ][ $function_key ] ); if ( ! $this->callbacks[ $priority ] ) { unset( $this->callbacks[ $priority ] ); $this->priorities = array_keys( $this->callbacks ); 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 * @since 6.9.0 Added the `$priority` parameter. * * @param string $hook_name Optional. The name of the filter hook. Default empty. * @param callable|string|array|false $callback Optional. The callback to check for. * This method can be called unconditionally to speculatively check * a callback that may or may not exist. Default false. * @param int|false $priority Optional. The specific priority at which to check for the callback. * Default false. * @return bool|int If `$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. * If `$callback` and `$priority` are both provided, a boolean is returned * for whether the specific function is registered at that priority. */ public function has_filter( $hook_name = '', $callback = false, $priority = false ) { if ( false === $callback ) { return $this->has_filters(); } $function_key = _wp_filter_build_unique_id( $hook_name, $callback, false ); if ( ! $function_key ) { return false; } if ( is_int( $priority ) ) { return isset( $this->callbacks[ $priority ][ $function_key ] ); } foreach ( $this->callbacks as $callback_priority => $callbacks ) { if ( isset( $callbacks[ $function_key ] ) ) { return $callback_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(); $this->priorities = array(); } elseif ( isset( $this->callbacks[ $priority ] ) ) { unset( $this->callbacks[ $priority ] ); $this->priorities = array_keys( $this->callbacks ); } 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 ] = $this->priorities; $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, $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 ] = $this->priorities; 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 ( $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. */ #[ReturnTypeWillChange] 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. */ #[ReturnTypeWillChange] public function offsetGet( $offset ) { return $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. */ #[ReturnTypeWillChange] public function offsetSet( $offset, $value ) { if ( is_null( $offset ) ) { $this->callbacks[] = $value; } else { $this->callbacks[ $offset ] = $value; } $this->priorities = array_keys( $this->callbacks ); } /** * 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. */ #[ReturnTypeWillChange] public function offsetUnset( $offset ) { unset( $this->callbacks[ $offset ] ); $this->priorities = array_keys( $this->callbacks ); } /** * 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. */ #[ReturnTypeWillChange] 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. */ #[ReturnTypeWillChange] 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 */ #[ReturnTypeWillChange] 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. */ #[ReturnTypeWillChange] 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 */ #[ReturnTypeWillChange] public function rewind() { reset( $this->callbacks ); } }