<?php
+/**
+ * The plugin API is located in this file, which allows for creating actions
+ * and filters and hooking functions, and methods. The functions or methods will
+ * then be run when the action or filter is called.
+ *
+ * The API callback examples reference functions, but can be methods of classes.
+ * To hook methods, you'll need to pass an array one of two ways.
+ *
+ * Any of the syntaxes explained in the PHP documentation for the
+ * {@link http://us2.php.net/manual/en/language.pseudo-types.php#language.types.callback 'callback'}
+ * type are valid.
+ *
+ * Also see the {@link http://codex.wordpress.org/Plugin_API Plugin API} for more information
+ * and examples on how to use a lot of these functions.
+ *
+ * @package WordPress
+ * @subpackage Plugin
+ * @since 1.5
+ */
/**
- * Hooks a function to a specific filter action.
+ * add_filter() - 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.
- * See the [Plugin API] for a list of filter hooks.
+ *
+ * To use the API, the following code should be used to bind a callback to the filter
+ * <code>
+ * function example_hook($example) { echo $example; }
+ *
+ * add_filter('example_filter', 'example_hook');
+ * </code>
+ *
+ * In WordPress 1.5.1+, hooked functions can take extra arguments that are set when
+ * the matching do_action() or apply_filters() call is run. The <tt>$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 <tt>do_action()</tt> or
+ * <tt>apply_filters()</tt> call is run. For example, the action <tt>comment_id_not_found</tt>
+ * 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 $tag The name of the filter to hook the <tt>$function_to_add</tt> 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 $accepted_args optional. The number of arguments the function accept (default 1). In WordPress 1.5.1+, hooked functions can take extra arguments that are set when the matching do_action() or apply_filters() call is run.
- * @return boolean true if the <tt>$function_to_add</tt> is added succesfully to filter <tt>$tag</tt>. How many arguments your function takes. In WordPress 1.5.1+, hooked functions can take extra arguments that are set when the matching <tt>do_action()</tt> or <tt>apply_filters()</tt> call is run. For example, the action <tt>comment_id_not_found</tt> will pass any functions that hook onto it the ID of the requested comment.
+ * @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;
- // So the format is wp_filter['tag']['array of priorities']['array of functions serialized']['array of ['array (functions, accepted_args)]']
$idx = _wp_filter_build_unique_id($tag, $function_to_add, $priority);
- $wp_filter[$tag][$priority][$idx] = array('function' => $function_to_add, 'accepted_args' => $accepted_args);
- //$wp_filter[$tag][$priority][serialize($function_to_add)] = array('function' => $function_to_add, 'accepted_args' => $accepted_args);
+ $wp_filter[$tag][$priority][$idx] = array('function' => $function_to_add, 'accepted_args' => $accepted_args);
unset( $merged_filters[ $tag ] );
return true;
}
/**
- * Call the functions added to a filter hook.
+ * has_filter() - 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 $function_to_check optional. If specified, return the priority of that function on this hook or false if not attached.
+ * @return int|boolean Optionally returns the priority on that hook for the specified function.
+ */
+function has_filter($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, $function_to_check, false) )
+ return false;
+
+ foreach ( array_keys($wp_filter[$tag]) as $priority ) {
+ if ( isset($wp_filter[$tag][$priority][$idx]) )
+ return $priority;
+ }
+
+ return false;
+}
+
+/**
+ * apply_filters() - Call the functions added to a filter hook.
*
* The callback functions attached to filter hook <tt>$tag</tt> 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 <tt>$tag</a> parameter.
- * @uses merge_filters Merges the filter hooks using this function.
+ *
+ * The function allows for additional arguments to be added and passed to hooks.
+ * <code>
+ * function example_hook($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 $merge_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 string $string The text on which the filters hooked to <tt>$tag</tt> are applied on.
+ * @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 string The text in <tt>$string</tt> after all hooked functions are applied to it.
+ * @return mixed The filtered value after all hooked functions are applied to it.
*/
-function apply_filters($tag, $string) {
- global $wp_filter, $merged_filters;
+function apply_filters($tag, $value) {
+ global $wp_filter, $merged_filters, $wp_current_filter;
- if ( !isset( $merged_filters[ $tag ] ) )
- merge_filters($tag);
+ $args = array();
+ $wp_current_filter[] = $tag;
+
+ // Do 'all' actions first
+ if ( isset($wp_filter['all']) ) {
+ $args = func_get_args();
+ _wp_call_all_hook($args);
+ }
- if ( !isset($wp_filter[$tag]) )
- return $string;
+ if ( !isset($wp_filter[$tag]) ) {
+ array_pop($wp_current_filter);
+ return $value;
+ }
+
+ // Sort
+ if ( !isset( $merged_filters[ $tag ] ) ) {
+ ksort($wp_filter[$tag]);
+ $merged_filters[ $tag ] = true;
+ }
reset( $wp_filter[ $tag ] );
- $args = func_get_args();
+ if ( empty($args) )
+ $args = func_get_args();
- do{
+ do {
foreach( (array) current($wp_filter[$tag]) as $the_ )
if ( !is_null($the_['function']) ){
- $args[1] = $string;
- $string = call_user_func_array($the_['function'], array_slice($args, 1, (int) $the_['accepted_args']));
+ $args[1] = $value;
+ $value = call_user_func_array($the_['function'], array_slice($args, 1, (int) $the_['accepted_args']));
}
} while ( next($wp_filter[$tag]) !== false );
- return $string;
-}
-
-/**
- * Merge the filter functions of a specific filter hook with generic filter functions.
- *
- * It is possible to defined generic filter functions using the filter hook
- * <em>all</e>. These functions are called for every filter tag. This function
- * merges the functions attached to the <em>all</em> hook with the functions
- * of a specific hoook defined by <tt>$tag</tt>.
- * @param string $tag The filter hook of which the functions should be merged.
- */
-function merge_filters($tag) {
- global $wp_filter, $merged_filters;
-
- if ( isset($wp_filter['all']) && is_array($wp_filter['all']) )
- $wp_filter[$tag] = array_merge($wp_filter['all'], (array) $wp_filter[$tag]);
+ array_pop( $wp_current_filter );
- if ( isset($wp_filter[$tag]) ){
- reset($wp_filter[$tag]);
- uksort($wp_filter[$tag], "strnatcasecmp");
- }
- $merged_filters[ $tag ] = true;
+ return $value;
}
/**
- * Removes a function from a specified filter hook.
+ * remove_filter() - Removes a function from a specified filter hook.
*
* This function removes a function attached to a specified filter hook. This
* method can be used to remove default functions attached to a specific filter
* hook and possibly replace them with a substitute.
+ *
+ * To remove a hook, the <tt>$function_to_remove</tt> and <tt>$priority</tt> 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 $accepted_args optional. The number of arguments the function accpets (default: 1).
- * @return boolean Whether the function is removed.
+ * @return boolean Whether the function existed before it was removed.
*/
function remove_filter($tag, $function_to_remove, $priority = 10, $accepted_args = 1) {
$function_to_remove = _wp_filter_build_unique_id($tag, $function_to_remove, $priority);
$r = isset($GLOBALS['wp_filter'][$tag][$priority][$function_to_remove]);
- unset($GLOBALS['wp_filter'][$tag][$priority][$function_to_remove]);
- unset($GLOBALS['merged_filters'][$tag]);
+ 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;
}
+
/**
- * Hooks a function on to a specific action.
+ * current_filter() - Return 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 );
+}
+
+
+/**
+ * add_action() - 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 $tag The name of the action to which the <tt>$function_to-add</tt> is hooked.
- * @param callback $function_to_add The name of the function you wish to be called. Note: any of the syntaxes explained in the PHP documentation for the 'callback' type (http://us2.php.net/manual/en/language.pseudo-types.php#language.types.callback) are valid.
+ * @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). 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.
- * @return boolean Always true.
+ * @param int $accepted_args optional. The number of arguments the function accept (default 1).
*/
function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
- add_filter($tag, $function_to_add, $priority, $accepted_args);
+ return add_filter($tag, $function_to_add, $priority, $accepted_args);
}
+
/**
- * Execute functions hooked on a specific action hook.
+ * do_action() - Execute functions hooked on a specific action hook.
*
* This function invokes all functions attached to action hook <tt>$tag</tt>.
* 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.
- * @uses merge_filters
+ *
+ * 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;
+ global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
if ( is_array($wp_actions) )
$wp_actions[] = $tag;
else
$wp_actions = array($tag);
+ $wp_current_filter[] = $tag;
+
+ // Do 'all' actions first
+ if ( isset($wp_filter['all']) ) {
+ $all_args = func_get_args();
+ _wp_call_all_hook($all_args);
+ }
+
+ if ( !isset($wp_filter[$tag]) ) {
+ array_pop($wp_current_filter);
+ return;
+ }
+
$args = array();
if ( is_array($arg) && 1 == count($arg) && is_object($arg[0]) ) // array(&$this)
$args[] =& $arg[0];
for ( $a = 2; $a < func_num_args(); $a++ )
$args[] = func_get_arg($a);
- merge_filters($tag);
+ // Sort
+ if ( !isset( $merged_filters[ $tag ] ) ) {
+ ksort($wp_filter[$tag]);
+ $merged_filters[ $tag ] = true;
+ }
- if ( !isset($wp_filter[$tag]) )
- return;
+ reset( $wp_filter[ $tag ] );
- do{
- foreach( (array) current($wp_filter[$tag]) as $the_ )
+ do {
+ foreach ( (array) current($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);
}
/**
- * Return the number times an action is fired.
+ * did_action() - Return the number 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
*/
}
/**
- * Execute functions hooked on a specific action hook, specifying arguments in a array.
+ * do_action_ref_array() - Execute functions hooked on a specific action hook, specifying arguments in an array.
*
- * This function is identical to {@link do_action}, but the argumetns passe to
+ * @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;
+ global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
if ( !is_array($wp_actions) )
$wp_actions = array($tag);
else
$wp_actions[] = $tag;
- merge_filters($tag);
+ $wp_current_filter[] = $tag;
+
+ // Do 'all' actions first
+ if ( isset($wp_filter['all']) ) {
+ $all_args = func_get_args();
+ _wp_call_all_hook($all_args);
+ }
- if ( !isset($wp_filter[$tag]) )
+ if ( !isset($wp_filter[$tag]) ) {
+ array_pop($wp_current_filter);
return;
+ }
- do{
+ // 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);
+}
+
+/**
+ * has_action() - 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 $function_to_check optional. If specified, return the priority of that function on this hook or false if not attached.
+ * @return int|boolean Optionally returns the priority on that hook for the specified function.
+ */
+function has_action($tag, $function_to_check = false) {
+ return has_filter($tag, $function_to_check);
}
/**
- * Removes a function from a specified action hook.
+ * remove_action() - 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).
//
/**
- * Gets the basename of a plugin.
+ * plugin_basename() - Gets the basename of a plugin.
*
* This method extract the name of a plugin from its filename.
+ *
+ * @package WordPress
+ * @subpackage Plugin
+ * @since 1.5
+ *
+ * @access private
+ *
* @param string $file The filename of plugin.
* @return string The name of a plugin.
*/
function plugin_basename($file) {
$file = str_replace('\\','/',$file); // sanitize for Win32 installs
$file = preg_replace('|/+|','/', $file); // remove any duplicate slash
- $file = preg_replace('|^.*/wp-content/plugins/|','',$file); // get relative path from plugins dir
+ $file = preg_replace('|^.*/' . PLUGINDIR . '/|','',$file); // get relative path from plugins dir
return $file;
}
/**
- * Hook a function on a plugin activation action hook.
+ * register_activation_hook() - Hook a function on a plugin activation action hook.
*
* When a plugin is activated, the action 'activate_PLUGINNAME' hook is
* activated. In the name of this hook, PLUGINNAME is replaced with the name of
* the plugin, including the optional subdirectory. For example, when the plugin
* is located in <tt>wp-content/plugin/sampleplugin/sample.php</tt>, then the
- * name of this hook will become 'activate_sampleplugin/sample.php'.
+ * name of this hook will become 'activate_sampleplugin/sample.php'
* When the plugin consists of only one file and is (as by default) located at
* <tt>wp-content/plugin/sample.php</tt> the name of this hook will be
* 'activate_sample.php'.
+ *
+ * @package WordPress
+ * @subpackage Plugin
+ * @since 2.0
+ *
+ * @access private
+ *
* @param string $file The filename of the plugin including the path.
* @param string $function the function hooked to the 'activate_PLUGIN' action.
*/
}
/**
- * Hook a function on a plugin deactivation action hook.
+ * register_deactivation_hook() - Hook a function on a plugin deactivation action hook.
*
* When a plugin is deactivated, the action 'deactivate_PLUGINNAME' hook is
* deactivated. In the name of this hook, PLUGINNAME is replaced with the name of
* When the plugin consists of only one file and is (as by default) located at
* <tt>wp-content/plugin/sample.php</tt> the name of this hook will be
* 'activate_sample.php'.
+ *
+ * @package WordPress
+ * @subpackage Plugin
+ * @since 2.0
+ *
+ * @access private
+ *
* @param string $file The filename of the plugin including the path.
* @param string $function the function hooked to the 'activate_PLUGIN' action.
*/
add_action('deactivate_' . $file, $function);
}
-function _wp_filter_build_unique_id($tag, $function, $priority = 10)
-{
+/**
+ * _wp_call_all_hook() - Calls the 'all' hook, which will process the functions hooked into it.
+ *
+ * The 'all' hook passes all of the arguments or parameters that were used for the
+ * hook, which this function was called for.
+ *
+ * This function is used internally for apply_filters(), do_action(), and do_action_ref_array()
+ * and is not meant to be used from outside those functions. This function does not check for the
+ * existence of the all hook, so it will fail unless the all hook exists prior to this function call.
+ *
+ * @package WordPress
+ * @subpackage Plugin
+ * @since 2.5
+ * @access private
+ *
+ * @uses $wp_filter Used to process all of the functions in the 'all' hook
+ *
+ * @param array $args The collected parameters from the hook that was called.
+ * @param string $hook Optional. The hook name that was used to call the 'all' hook.
+ */
+function _wp_call_all_hook($args) {
+ global $wp_filter;
+
+ reset( $wp_filter['all'] );
+ do {
+ foreach( (array) current($wp_filter['all']) as $the_ )
+ if ( !is_null($the_['function']) )
+ call_user_func_array($the_['function'], $args);
+
+ } while ( next($wp_filter['all']) !== false );
+}
+
+/**
+ * _wp_filter_build_unique_id() - 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
+ * @since 2.2.3
+ *
+ * @link http://trac.wordpress.org/ticket/3875
+ *
+ * @access private
+ *
+ * @global array $wp_filter Storage for all of the filters and actions
+ * @param string $tag Used in counting how many hooks were applied
+ * @param string|array $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.
+ * @param string $type filter or action
+ * @return string Unique ID for usage as array key
+ */
+function _wp_filter_build_unique_id($tag, $function, $priority) {
global $wp_filter;
// If function then just skip all of the tests and not overwrite the following.
- // Static Calling
- if( is_string($function) )
+ if ( is_string($function) )
return $function;
// Object Class Calling
- else if(is_object($function[0]) )
- {
+ else if (is_object($function[0]) ) {
$obj_idx = get_class($function[0]).$function[1];
- if( is_null($function[0]->wp_filter_id) ) {
+ if ( !isset($function[0]->wp_filter_id) ) {
+ if ( false === $priority )
+ return false;
$count = count((array)$wp_filter[$tag][$priority]);
$function[0]->wp_filter_id = $count;
$obj_idx .= $count;
$obj_idx .= $function[0]->wp_filter_id;
return $obj_idx;
}
- else if( is_string($function[0]) )
+ // Static Calling
+ else if ( is_string($function[0]) )
return $function[0].$function[1];
}
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