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