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phpdoc for plugin API. Props darkdragon. fixes #5225

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git-svn-id: http://svn.automattic.com/wordpress/trunk@6276 1a063a9b-81f0-0310-95a4-ce76da25c4cd
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ryan 2007-10-19 17:45:08 +00:00
parent 5fb4d6ab00
commit babd1e1a7f
1 changed files with 196 additions and 45 deletions
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239
wp-includes/plugin.php
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@ -1,27 +1,79 @@
<?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.
*
* For static methods (you won't have access to the <tt>$this</tt> variable in the
* method):
* <code>array('class_name', 'method_name');</code>
*
* The second method will need the reference to the object to have access to the
* method.
* <code>array(&$this, 'method_name');</code>
* <code>
* $obj = new myObject();
* array(&$obj, 'method_name');
* </code>
* 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.
* 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 1.5
* @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[ $tag ] );
return true;
}
@ -33,20 +85,35 @@ function add_filter($tag, $function_to_add, $priority = 10, $accepted_args = 1)
* calling this function. This function can be used to create a new filter hook
* by simply calling this function with the name of the new hook specified using
* the <tt>$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
* }
* $value = apply_filters('example_filter', 'filter me', 'arg1', 'arg2');
* </code>
*
* @package WordPress
* @subpackage Plugin
* @since 1.5
* @global array $wp_filter Stores all of the filters
* @global array $merge_filters Merges the filter hooks using this function.
*
* @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 string $value The value on which the filters hooked to <tt>$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>$string</tt> after all hooked functions are applied to it.
*/
function apply_filters($tag, $string) {
function apply_filters($tag, $value) {
global $wp_filter, $merged_filters;
if ( !isset( $merged_filters[ $tag ] ) )
merge_filters($tag);
if ( !isset($wp_filter[$tag]) )
return $string;
return $value;
reset( $wp_filter[ $tag ] );
@ -55,13 +122,13 @@ function apply_filters($tag, $string) {
do{
foreach( (array) current($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;
return $value;
}
/**
@ -70,7 +137,17 @@ function apply_filters($tag, $string) {
* It is possible to defined generic filter functions using the filter hook
* <em>all</e>. These functions are called for every filter tag. This function
* merges the functions attached to the <em>all</em> hook with the functions
* of a specific hoook defined by <tt>$tag</tt>.
* of a specific hook defined by <tt>$tag</tt>.
*
* Bugged if you hook into 'all' tag, then you <strong>will</strong> lose all priority
* information. {@link http://trac.wordpress.org/ticket/4715 Bug #4715} for more information.
*
* @package WordPress
* @subpackage Plugin
* @since 1.5
* @global array $wp_filter Stores all of the filters
* @global array $merge_filters Merges the filter hooks using this function.
*
* @param string $tag The filter hook of which the functions should be merged.
*/
function merge_filters($tag) {
@ -92,11 +169,20 @@ function merge_filters($tag) {
* This function removes a function attached to a specified filter hook. This
* method can be used to remove default functions attached to a specific filter
* hook and possibly replace them with a substitute.
*
* To remove a hook, the <tt>$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 1.5
*
* @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, $priority);
@ -117,11 +203,16 @@ function remove_filter($tag, $function_to_remove, $priority = 10, $accepted_args
* 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 1.5
*
* @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, $accepted_args);
@ -133,9 +224,21 @@ function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1)
* This function invokes all functions attached to action hook <tt>$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 1.5
* @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, $wp_actions;
@ -169,6 +272,12 @@ function do_action($tag, $arg = '') {
/**
* 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
*/
@ -182,12 +291,22 @@ function did_action($tag) {
}
/**
* Execute functions hooked on a specific action hook, specifying arguments in a array.
* Execute functions hooked on a specific action hook, specifying arguments in an array.
*
* This function is identical to {@link do_action}, but the argumetns passe to
* @see do_action() This function is identical, but the arguments passed to
* the functions hooked to <tt>$tag</tt> are supplied using an array.
*
* @uses merge_filters()
*
* @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, $wp_actions;
@ -217,6 +336,13 @@ function do_action_ref_array($tag, $args) {
* 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.
*
* @uses remove_filter() Uses remove_filter to remove actions added.
*
* @package WordPress
* @subpackage Plugin
* @since 1.5
*
* @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 $priority optional The priority of the function (default: 10).
@ -235,6 +361,13 @@ function remove_action($tag, $function_to_remove, $priority = 10, $accepted_args
* 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 $file The filename of plugin.
* @return string The name of a plugin.
*/
@ -252,10 +385,17 @@ function plugin_basename($file) {
* 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 1.5
*
* @access private
*
* @param string $file The filename of the plugin including the path.
* @param string $function the function hooked to the 'activate_PLUGIN' action.
*/
@ -275,6 +415,13 @@ function register_activation_hook($file, $function) {
* 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 $function the function hooked to the 'activate_PLUGIN' action.
*/
@ -284,27 +431,31 @@ function register_deactivation_hook($file, $function) {
}
/**
* 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
*
* _wp_filter_build_unique_id() - Build Unique ID for storage and retrieval
*
* This function is used to fix the issue where serialized, when used with
* classes that updated their properties, wouldn't be able to remove actions.
*
* How it works is that it first checks if the $function parameter is a string
* and passes it through, untouched. Functions won't need to be changed, since
* there can only be one declared.
*
* The second type that will be passed through untouched, is for static methods
* in classes. They don't need to be changed since they are much like functions
* in that you can only call one of them.
*
* The main purpose of this function is for classes, which can have more than
* one declared and you want to add more than one hook for each one that is
* declared, or want to change properties internal of the class that you declared
* the hook.
*
* @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 string|array $function Used for creating unique id
* @param int $priority Used in counting how many hooks were applied
@ -315,14 +466,13 @@ function _wp_filter_build_unique_id($tag, $function, $priority = 10)
global $wp_filter;
// If function then just skip all of the tests and not overwrite the following.
// Static Calling
if( is_string($function) )
return $function;
// Object Class Calling
else if(is_object($function[0]) )
{
$obj_idx = get_class($function[0]).$function[1];
if( is_null($function[0]->wp_filter_id) ) {
if( is_null($function[0]->wp_filter_id) ) { // This should be instead of is_null() change to !isset() to fix notice
$count = count((array)$wp_filter[$tag][$priority]);
$function[0]->wp_filter_id = $count;
$obj_idx .= $count;
@ -331,6 +481,7 @@ function _wp_filter_build_unique_id($tag, $function, $priority = 10)
$obj_idx .= $function[0]->wp_filter_id;
return $obj_idx;
}
// Static Calling
else if( is_string($function[0]) )
return $function[0].$function[1];
}