* @since 1.5
*/
+// Initialize the filter globals.
+global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
+
+if ( ! isset( $wp_filter ) )
+ $wp_filter = array();
+
+if ( ! isset( $wp_actions ) )
+ $wp_actions = array();
+
+if ( ! isset( $merged_filters ) )
+ $merged_filters = array();
+
+if ( ! isset( $wp_current_filter ) )
+ $wp_current_filter = array();
+
/**
* 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.
+ * WordPress offers filter hooks to allow plugins to modify
+ * various types of internal data at runtime.
+ *
+ * A plugin can modify data by binding a callback to a filter hook. When the filter
+ * is later applied, each bound callback is run in order of priority, and given
+ * the opportunity to modify a value by returning a new value.
*
- * To use the API, the following code should be used to bind a callback to the
- * filter.
+ * The following example shows how a callback function is bound to a filter hook.
+ * Note that $example is passed to the callback, (maybe) modified, then returned:
*
* <code>
- * function example_hook($example) { echo $example; }
- * add_filter('example_filter', 'example_hook');
+ * function example_callback( $example ) {
+ * // Maybe modify $example in some way
+ * return $example;
+ * }
+ * add_filter( 'example_filter', 'example_callback' );
* </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.
+ * Since WordPress 1.5.1, bound callbacks can take as many arguments as are
+ * passed as parameters in the corresponding apply_filters() call. The $accepted_args
+ * parameter allows for calling functions only when the number of args match.
*
- * <strong>Note:</strong> the function will return true no matter if the
- * function was hooked fails or not. There are no checks for whether the
- * function exists beforehand and no checks to whether the <tt>$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.
+ * <strong>Note:</strong> the function will return true whether or not the callback
+ * is valid. It is up to you to take care. 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 $wp_filter A multidimensional array of all hooks and the callbacks hooked to them.
* @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).
+ * @since 0.71
+ *
+ * @param string $tag The name of the filter to hook the $function_to_add callback to.
+ * @param callback $function_to_add The callback to be run when the filter is applied.
+ * @param int $priority (optional) The order in which the functions associated with a particular action 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 action.
+ * Default 10.
+ * @param int $accepted_args (optional) The number of arguments the function accepts.
+ * Default 1.
* @return boolean true
*/
-function add_filter($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
+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);
* @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.
+ * @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 $wp_filter;
*
* The function allows for additional arguments to be added and passed to hooks.
* <code>
- * function example_hook($string, $arg1, $arg2)
- * {
- * //Do stuff
- * return $string;
+ * // Our filter callback function
+ * function example_callback( $string, $arg1, $arg2 ) {
+ * // (maybe) modify $string
+ * return $string;
* }
- * $value = apply_filters('example_filter', 'filter me', 'arg1', 'arg2');
+ * add_filter( 'example_filter', 'example_callback', 10, 3 );
+ *
+ * // Apply the filters by calling the 'example_callback' function we
+ * // "hooked" to 'example_filter' using the add_filter() function above.
+ * // - 'example_filter' is the filter hook $tag
+ * // - 'filter me' is the value being filtered
+ * // - $arg1 and $arg2 are the additional arguments passed to the callback.
+ * $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_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.
+ * @since 0.71
+ *
+ * @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>.
+ * @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) {
+function apply_filters( $tag, $value ) {
global $wp_filter, $merged_filters, $wp_current_filter;
$args = array();
* @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).
+ * @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, $accepted_args = 1) {
+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]);
return end( $wp_current_filter );
}
-
/**
* Hooks a function on to a specific action.
*
return add_filter($tag, $function_to_add, $priority, $accepted_args);
}
-
/**
* Execute functions hooked on a specific action hook.
*
function do_action($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
}
/**
- * Retrieve the number times an action is fired.
+ * Retrieve the number of times an action is fired.
*
* @package WordPress
* @subpackage Plugin
function did_action($tag) {
global $wp_actions;
- if ( ! isset( $wp_actions ) || ! isset( $wp_actions[$tag] ) )
+ if ( ! isset( $wp_actions[ $tag ] ) )
return 0;
return $wp_actions[$tag];
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
* @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.
+ * @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);
* @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).
- * @param int $accepted_args optional. The number of arguments the function accpets (default: 1).
* @return boolean Whether the function is removed.
*/
-function remove_action($tag, $function_to_remove, $priority = 10, $accepted_args = 1) {
- return remove_filter($tag, $function_to_remove, $priority, $accepted_args);
+function remove_action( $tag, $function_to_remove, $priority = 10 ) {
+ return remove_filter( $tag, $function_to_remove, $priority );
}
/**
* Set the activation hook for a plugin.
*
* 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 wp-content/plugin/sampleplugin/sample.php, then the 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
- * wp-content/plugin/sample.php the name of this hook will be
+ * called. 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 wp-content/plugins/sampleplugin/sample.php, then
+ * the 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
+ * wp-content/plugins/sample.php the name of this hook will be
* 'activate_sample.php'.
*
* @package WordPress
* Set the deactivation hook for a plugin.
*
* When a plugin is deactivated, the action 'deactivate_PLUGINNAME' hook is
- * deactivated. In the name of this hook, PLUGINNAME is replaced with the name
+ * called. 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 wp-content/plugin/sampleplugin/sample.php, then
- * the name of this hook will become 'activate_sampleplugin/sample.php'.
+ * plugin is located in wp-content/plugins/sampleplugin/sample.php, then
+ * the name of this hook will become 'deactivate_sampleplugin/sample.php'.
*
* When the plugin consists of only one file and is (as by default) located at
- * wp-content/plugin/sample.php the name of this hook will be
- * 'activate_sample.php'.
+ * wp-content/plugins/sample.php the name of this hook will be
+ * 'deactivate_sample.php'.
*
* @package WordPress
* @subpackage Plugin
* @since 2.0
*
* @param string $file The filename of the plugin including the path.
- * @param callback $function the function hooked to the 'activate_PLUGIN' action.
+ * @param callback $function the function hooked to the 'deactivate_PLUGIN' action.
*/
function register_deactivation_hook($file, $function) {
$file = plugin_basename($file);
* @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;
* @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 uniqe 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 $wp_filter;
}
} else if ( is_string($function[0]) ) {
// Static Calling
- return $function[0].$function[1];
+ return $function[0] . '::' . $function[1];
}
}
-
-?>
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