class WP_Hook {}

Source

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 ) {	$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 ) {	$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 ] );	$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 * * @param string $hook_name Optional. The name of the filter hook. Default empty. * @param callable|string|array|false $callback Optional. The callback to check for. * This method can be called unconditionally to speculatively check * a callback that may or may not exist. Default false. * @return bool|int If `$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();	$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 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. */	#[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 );	} } 

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