Ticket #21412: hookable-dropins.diff

Index: wp-includes/plugin.php
===================================================================
--- wp-includes/plugin.php      (revision 21358)
+++ wp-includes/plugin.php      (working copy)
@@ -19,530 +19,6 @@
  * @since 1.5
  */
 
-/**
- * Hooks a function or method to a specific filter action.
- *
- * Filters are the hooks that WordPress launches to modify text of various types
- * before adding it to the database or sending it to the browser screen. Plugins
- * can specify that one or more of its PHP functions is executed to
- * modify specific types of text at these times, using the Filter API.
- *
- * To use the API, the following code should be used to bind a callback to the
- * filter.
- *
- * <code>
- * function example_hook($example) { echo $example; }
- * add_filter('example_filter', 'example_hook');
- * </code>
- *
- * In WordPress 1.5.1+, hooked functions can take extra arguments that are set
- * when the matching do_action() or apply_filters() call is run. The
- * $accepted_args allow for calling functions only when the number of args
- * match. Hooked functions can take extra arguments that are set when the
- * matching do_action() or apply_filters() call is run. For example, the action
- * comment_id_not_found will pass any functions that hook onto it the ID of the
- * requested comment.
- *
- * <strong>Note:</strong> the function will return true no matter if the
- * function was hooked fails or not. There are no checks for whether the
- * function exists beforehand and no checks to whether the <tt>$function_to_add
- * is even a string. It is up to you to take care and this is done for
- * optimization purposes, so everything is as quick as possible.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 0.71
- * @global array $wp_filter Stores all of the filters added in the form of
- *     wp_filter['tag']['array of priorities']['array of functions serialized']['array of ['array (functions, accepted_args)']']
- * @global array $merged_filters Tracks the tags that need to be merged for later. If the hook is added, it doesn't need to run through that process.
- *
- * @param string $tag The name of the filter to hook the $function_to_add to.
- * @param callback $function_to_add The name of the function to be called when the filter is applied.
- * @param int $priority optional. Used to specify the order in which the functions associated with a particular action are executed (default: 10). Lower numbers correspond with earlier execution, and functions with the same priority are executed in the order in which they were added to the action.
- * @param int $accepted_args optional. The number of arguments the function accept (default 1).
- * @return boolean true
- */
-function add_filter($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
-       global $wp_filter, $merged_filters;
-
-       $idx = _wp_filter_build_unique_id($tag, $function_to_add, $priority);
-       $wp_filter[$tag][$priority][$idx] = array('function' => $function_to_add, 'accepted_args' => $accepted_args);
-       unset( $merged_filters[ $tag ] );
-       return true;
-}
-
-/**
- * Check if any filter has been registered for a hook.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 2.5
- * @global array $wp_filter Stores all of the filters
- *
- * @param string $tag The name of the filter hook.
- * @param callback $function_to_check optional.
- * @return mixed If $function_to_check 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.
- *     When using the $function_to_check argument, this function may return a non-boolean value that evaluates to false
- *     (e.g.) 0, so use the === operator for testing the return value.
- */
-function has_filter($tag, $function_to_check = false) {
-       global $wp_filter;
-
-       $has = !empty($wp_filter[$tag]);
-       if ( false === $function_to_check || false == $has )
-               return $has;
-
-       if ( !$idx = _wp_filter_build_unique_id($tag, $function_to_check, false) )
-               return false;
-
-       foreach ( (array) array_keys($wp_filter[$tag]) as $priority ) {
-               if ( isset($wp_filter[$tag][$priority][$idx]) )
-                       return $priority;
-       }
-
-       return false;
-}
-
-/**
- * Call the functions added to a filter hook.
- *
- * The callback functions attached to filter hook $tag are invoked by calling
- * this function. This function can be used to create a new filter hook by
- * simply calling this function with the name of the new hook specified using
- * the $tag parameter.
- *
- * The function allows for additional arguments to be added and passed to hooks.
- * <code>
- * function example_hook($string, $arg1, $arg2)
- * {
- *             //Do stuff
- *             return $string;
- * }
- * $value = apply_filters('example_filter', 'filter me', 'arg1', 'arg2');
- * </code>
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 0.71
- * @global array $wp_filter Stores all of the filters
- * @global array $merged_filters Merges the filter hooks using this function.
- * @global array $wp_current_filter stores the list of current filters with the current one last
- *
- * @param string $tag The name of the filter hook.
- * @param mixed $value The value on which the filters hooked to <tt>$tag</tt> are applied on.
- * @param mixed $var,... Additional variables passed to the functions hooked to <tt>$tag</tt>.
- * @return mixed The filtered value after all hooked functions are applied to it.
- */
-function apply_filters($tag, $value) {
-       global $wp_filter, $merged_filters, $wp_current_filter;
-
-       $args = array();
-
-       // Do 'all' actions first
-       if ( isset($wp_filter['all']) ) {
-               $wp_current_filter[] = $tag;
-               $args = func_get_args();
-               _wp_call_all_hook($args);
-       }
-
-       if ( !isset($wp_filter[$tag]) ) {
-               if ( isset($wp_filter['all']) )
-                       array_pop($wp_current_filter);
-               return $value;
-       }
-
-       if ( !isset($wp_filter['all']) )
-               $wp_current_filter[] = $tag;
-
-       // Sort
-       if ( !isset( $merged_filters[ $tag ] ) ) {
-               ksort($wp_filter[$tag]);
-               $merged_filters[ $tag ] = true;
-       }
-
-       reset( $wp_filter[ $tag ] );
-
-       if ( empty($args) )
-               $args = func_get_args();
-
-       do {
-               foreach( (array) current($wp_filter[$tag]) as $the_ )
-                       if ( !is_null($the_['function']) ){
-                               $args[1] = $value;
-                               $value = call_user_func_array($the_['function'], array_slice($args, 1, (int) $the_['accepted_args']));
-                       }
-
-       } while ( next($wp_filter[$tag]) !== false );
-
-       array_pop( $wp_current_filter );
-
-       return $value;
-}
-
-/**
- * Execute functions hooked on a specific filter hook, specifying arguments in an array.
- *
- * @see apply_filters() This function is identical, but the arguments passed to the
- * functions hooked to <tt>$tag</tt> are supplied using an array.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 3.0.0
- * @global array $wp_filter Stores all of the filters
- * @global array $merged_filters Merges the filter hooks using this function.
- * @global array $wp_current_filter stores the list of current filters with the current one last
- *
- * @param string $tag The name of the filter hook.
- * @param array $args The arguments supplied to the functions hooked to <tt>$tag</tt>
- * @return mixed The filtered value after all hooked functions are applied to it.
- */
-function apply_filters_ref_array($tag, $args) {
-       global $wp_filter, $merged_filters, $wp_current_filter;
-
-       // Do 'all' actions first
-       if ( isset($wp_filter['all']) ) {
-               $wp_current_filter[] = $tag;
-               $all_args = func_get_args();
-               _wp_call_all_hook($all_args);
-       }
-
-       if ( !isset($wp_filter[$tag]) ) {
-               if ( isset($wp_filter['all']) )
-                       array_pop($wp_current_filter);
-               return $args[0];
-       }
-
-       if ( !isset($wp_filter['all']) )
-               $wp_current_filter[] = $tag;
-
-       // Sort
-       if ( !isset( $merged_filters[ $tag ] ) ) {
-               ksort($wp_filter[$tag]);
-               $merged_filters[ $tag ] = true;
-       }
-
-       reset( $wp_filter[ $tag ] );
-
-       do {
-               foreach( (array) current($wp_filter[$tag]) as $the_ )
-                       if ( !is_null($the_['function']) )
-                               $args[0] = call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
-
-       } while ( next($wp_filter[$tag]) !== false );
-
-       array_pop( $wp_current_filter );
-
-       return $args[0];
-}
-
-/**
- * Removes a function from a specified filter hook.
- *
- * This function removes a function attached to a specified filter hook. This
- * method can be used to remove default functions attached to a specific filter
- * hook and possibly replace them with a substitute.
- *
- * To remove a hook, the $function_to_remove and $priority arguments must match
- * when the hook was added. This goes for both filters and actions. No warning
- * will be given on removal failure.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 1.2
- *
- * @param string $tag The filter hook to which the function to be removed is hooked.
- * @param callback $function_to_remove The name of the function which should be removed.
- * @param int $priority optional. The priority of the function (default: 10).
- * @param int $accepted_args optional. The number of arguments the function accepts (default: 1).
- * @return boolean Whether the function existed before it was removed.
- */
-function remove_filter( $tag, $function_to_remove, $priority = 10 ) {
-       $function_to_remove = _wp_filter_build_unique_id($tag, $function_to_remove, $priority);
-
-       $r = isset($GLOBALS['wp_filter'][$tag][$priority][$function_to_remove]);
-
-       if ( true === $r) {
-               unset($GLOBALS['wp_filter'][$tag][$priority][$function_to_remove]);
-               if ( empty($GLOBALS['wp_filter'][$tag][$priority]) )
-                       unset($GLOBALS['wp_filter'][$tag][$priority]);
-               unset($GLOBALS['merged_filters'][$tag]);
-       }
-
-       return $r;
-}
-
-/**
- * Remove all of the hooks from a filter.
- *
- * @since 2.7
- *
- * @param string $tag The filter to remove hooks from.
- * @param int $priority The priority number to remove.
- * @return bool True when finished.
- */
-function remove_all_filters($tag, $priority = false) {
-       global $wp_filter, $merged_filters;
-
-       if( isset($wp_filter[$tag]) ) {
-               if( false !== $priority && isset($wp_filter[$tag][$priority]) )
-                       unset($wp_filter[$tag][$priority]);
-               else
-                       unset($wp_filter[$tag]);
-       }
-
-       if( isset($merged_filters[$tag]) )
-               unset($merged_filters[$tag]);
-
-       return true;
-}
-
-/**
- * Retrieve the name of the current filter or action.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 2.5
- *
- * @return string Hook name of the current filter or action.
- */
-function current_filter() {
-       global $wp_current_filter;
-       return end( $wp_current_filter );
-}
-
-/**
- * Hooks a function on to a specific action.
- *
- * Actions are the hooks that the WordPress core launches at specific points
- * during execution, or when specific events occur. Plugins can specify that
- * one or more of its PHP functions are executed at these points, using the
- * Action API.
- *
- * @uses add_filter() Adds an action. Parameter list and functionality are the same.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 1.2
- *
- * @param string $tag The name of the action to which the $function_to_add is hooked.
- * @param callback $function_to_add The name of the function you wish to be called.
- * @param int $priority optional. Used to specify the order in which the functions associated with a particular action are executed (default: 10). Lower numbers correspond with earlier execution, and functions with the same priority are executed in the order in which they were added to the action.
- * @param int $accepted_args optional. The number of arguments the function accept (default 1).
- */
-function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
-       return add_filter($tag, $function_to_add, $priority, $accepted_args);
-}
-
-/**
- * Execute functions hooked on a specific action hook.
- *
- * This function invokes all functions attached to action hook $tag. It is
- * possible to create new action hooks by simply calling this function,
- * specifying the name of the new hook using the <tt>$tag</tt> parameter.
- *
- * You can pass extra arguments to the hooks, much like you can with
- * apply_filters().
- *
- * @see apply_filters() This function works similar with the exception that
- * nothing is returned and only the functions or methods are called.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 1.2
- * @global array $wp_filter Stores all of the filters
- * @global array $wp_actions Increments the amount of times action was triggered.
- *
- * @param string $tag The name of the action to be executed.
- * @param mixed $arg,... Optional additional arguments which are passed on to the functions hooked to the action.
- * @return null Will return null if $tag does not exist in $wp_filter array
- */
-function do_action($tag, $arg = '') {
-       global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
-
-       if ( ! isset($wp_actions) )
-               $wp_actions = array();
-
-       if ( ! isset($wp_actions[$tag]) )
-               $wp_actions[$tag] = 1;
-       else
-               ++$wp_actions[$tag];
-
-       // Do 'all' actions first
-       if ( isset($wp_filter['all']) ) {
-               $wp_current_filter[] = $tag;
-               $all_args = func_get_args();
-               _wp_call_all_hook($all_args);
-       }
-
-       if ( !isset($wp_filter[$tag]) ) {
-               if ( isset($wp_filter['all']) )
-                       array_pop($wp_current_filter);
-               return;
-       }
-
-       if ( !isset($wp_filter['all']) )
-               $wp_current_filter[] = $tag;
-
-       $args = array();
-       if ( is_array($arg) && 1 == count($arg) && isset($arg[0]) && is_object($arg[0]) ) // array(&$this)
-               $args[] =& $arg[0];
-       else
-               $args[] = $arg;
-       for ( $a = 2; $a < func_num_args(); $a++ )
-               $args[] = func_get_arg($a);
-
-       // Sort
-       if ( !isset( $merged_filters[ $tag ] ) ) {
-               ksort($wp_filter[$tag]);
-               $merged_filters[ $tag ] = true;
-       }
-
-       reset( $wp_filter[ $tag ] );
-
-       do {
-               foreach ( (array) current($wp_filter[$tag]) as $the_ )
-                       if ( !is_null($the_['function']) )
-                               call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
-
-       } while ( next($wp_filter[$tag]) !== false );
-
-       array_pop($wp_current_filter);
-}
-
-/**
- * Retrieve the number of times an action is fired.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 2.1
- * @global array $wp_actions Increments the amount of times action was triggered.
- *
- * @param string $tag The name of the action hook.
- * @return int The number of times action hook <tt>$tag</tt> is fired
- */
-function did_action($tag) {
-       global $wp_actions;
-
-       if ( ! isset( $wp_actions ) || ! isset( $wp_actions[$tag] ) )
-               return 0;
-
-       return $wp_actions[$tag];
-}
-
-/**
- * Execute functions hooked on a specific action hook, specifying arguments in an array.
- *
- * @see do_action() This function is identical, but the arguments passed to the
- * functions hooked to <tt>$tag</tt> are supplied using an array.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 2.1
- * @global array $wp_filter Stores all of the filters
- * @global array $wp_actions Increments the amount of times action was triggered.
- *
- * @param string $tag The name of the action to be executed.
- * @param array $args The arguments supplied to the functions hooked to <tt>$tag</tt>
- * @return null Will return null if $tag does not exist in $wp_filter array
- */
-function do_action_ref_array($tag, $args) {
-       global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
-
-       if ( ! isset($wp_actions) )
-               $wp_actions = array();
-
-       if ( ! isset($wp_actions[$tag]) )
-               $wp_actions[$tag] = 1;
-       else
-               ++$wp_actions[$tag];
-
-       // Do 'all' actions first
-       if ( isset($wp_filter['all']) ) {
-               $wp_current_filter[] = $tag;
-               $all_args = func_get_args();
-               _wp_call_all_hook($all_args);
-       }
-
-       if ( !isset($wp_filter[$tag]) ) {
-               if ( isset($wp_filter['all']) )
-                       array_pop($wp_current_filter);
-               return;
-       }
-
-       if ( !isset($wp_filter['all']) )
-               $wp_current_filter[] = $tag;
-
-       // Sort
-       if ( !isset( $merged_filters[ $tag ] ) ) {
-               ksort($wp_filter[$tag]);
-               $merged_filters[ $tag ] = true;
-       }
-
-       reset( $wp_filter[ $tag ] );
-
-       do {
-               foreach( (array) current($wp_filter[$tag]) as $the_ )
-                       if ( !is_null($the_['function']) )
-                               call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
-
-       } while ( next($wp_filter[$tag]) !== false );
-
-       array_pop($wp_current_filter);
-}
-
-/**
- * Check if any action has been registered for a hook.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 2.5
- * @see has_filter() has_action() is an alias of has_filter().
- *
- * @param string $tag The name of the action hook.
- * @param callback $function_to_check optional.
- * @return mixed If $function_to_check 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.
- *     When using the $function_to_check argument, this function may return a non-boolean value that evaluates to false
- *     (e.g.) 0, so use the === operator for testing the return value.
- */
-function has_action($tag, $function_to_check = false) {
-       return has_filter($tag, $function_to_check);
-}
-
-/**
- * Removes a function from a specified action hook.
- *
- * This function removes a function attached to a specified action hook. This
- * method can be used to remove default functions attached to a specific filter
- * hook and possibly replace them with a substitute.
- *
- * @package WordPress
- * @subpackage Plugin
- * @since 1.2
- *
- * @param string $tag The action hook to which the function to be removed is hooked.
- * @param callback $function_to_remove The name of the function which should be removed.
- * @param int $priority optional The priority of the function (default: 10).
- * @return boolean Whether the function is removed.
- */
-function remove_action( $tag, $function_to_remove, $priority = 10 ) {
-       return remove_filter( $tag, $function_to_remove, $priority );
-}
-
-/**
- * Remove all of the hooks from an action.
- *
- * @since 2.7
- *
- * @param string $tag The action to remove hooks from.
- * @param int $priority The priority number to remove them from.
- * @return bool True when finished.
- */
-function remove_all_actions($tag, $priority = false) {
-       return remove_all_filters($tag, $priority);
-}
-
 //
 // Functions for handling plugins.
 //
@@ -720,70 +196,3 @@
 
        } while ( next($wp_filter['all']) !== false );
 }
-
-/**
- * Build Unique ID for storage and retrieval.
- *
- * The old way to serialize the callback caused issues and this function is the
- * solution. It works by checking for objects and creating an a new property in
- * the class to keep track of the object and new objects of the same class that
- * need to be added.
- *
- * It also allows for the removal of actions and filters for objects after they
- * change class properties. It is possible to include the property $wp_filter_id
- * in your class and set it to "null" or a number to bypass the workaround.
- * However this will prevent you from adding new classes and any new classes
- * will overwrite the previous hook by the same class.
- *
- * Functions and static method callbacks are just returned as strings and
- * shouldn't have any speed penalty.
- *
- * @package WordPress
- * @subpackage Plugin
- * @access private
- * @since 2.2.3
- * @link http://trac.wordpress.org/ticket/3875
- *
- * @global array $wp_filter Storage for all of the filters and actions
- * @param string $tag Used in counting how many hooks were applied
- * @param callback $function Used for creating unique id
- * @param int|bool $priority Used in counting how many hooks were applied. If === false and $function is an object reference, we return the unique id only if it already has one, false otherwise.
- * @return string|bool Unique ID for usage as array key or false if $priority === false and $function is an object reference, and it does not already have a unique id.
- */
-function _wp_filter_build_unique_id($tag, $function, $priority) {
-       global $wp_filter;
-       static $filter_id_count = 0;
-
-       if ( is_string($function) )
-               return $function;
-
-       if ( is_object($function) ) {
-               // Closures are currently implemented as objects
-               $function = array( $function, '' );
-       } else {
-               $function = (array) $function;
-       }
-
-       if (is_object($function[0]) ) {
-               // Object Class Calling
-               if ( function_exists('spl_object_hash') ) {
-                       return spl_object_hash($function[0]) . $function[1];
-               } else {
-                       $obj_idx = get_class($function[0]).$function[1];
-                       if ( !isset($function[0]->wp_filter_id) ) {
-                               if ( false === $priority )
-                                       return false;
-                               $obj_idx .= isset($wp_filter[$tag][$priority]) ? count((array)$wp_filter[$tag][$priority]) : $filter_id_count;
-                               $function[0]->wp_filter_id = $filter_id_count;
-                               ++$filter_id_count;
-                       } else {
-                               $obj_idx .= $function[0]->wp_filter_id;
-                       }
-
-                       return $obj_idx;
-               }
-       } else if ( is_string($function[0]) ) {
-               // Static Calling
-               return $function[0].$function[1];
-       }
-}
Index: wp-settings.php
===================================================================
--- wp-settings.php     (revision 21358)
+++ wp-settings.php     (working copy)
@@ -21,6 +21,8 @@
 require( ABSPATH . WPINC . '/load.php' );
 require( ABSPATH . WPINC . '/default-constants.php' );
 require( ABSPATH . WPINC . '/version.php' );
+require( ABSPATH . WPINC . '/hooks.php' );
+require( ABSPATH . WPINC . '/dropins.php' );
 
 // Set initial default constants including WP_MEMORY_LIMIT, WP_MAX_MEMORY_LIMIT, WP_DEBUG, WP_CONTENT_DIR and WP_CACHE.
 wp_initial_constants( );
@@ -54,6 +56,12 @@
 // Check if we're in WP_DEBUG mode.
 wp_debug_mode();
 
+// Load any potential dropins found /wp-content/dropins/
+wp_load_dropins();
+
+// Run the hook-based page cache.
+do_action( 'page_cache' );
+
 // For an advanced caching plugin to use. Uses a static drop-in because you would only want one.
 if ( WP_CACHE )
        WP_DEBUG ? include( WP_CONTENT_DIR . '/advanced-cache.php' ) : @include( WP_CONTENT_DIR . '/advanced-cache.php' );