548 lines
19 KiB
PHP
548 lines
19 KiB
PHP
<?php
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/**
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* The plugin API is located in this file, which allows for creating actions
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* and filters and hooking functions, and methods. The functions or methods will
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* then be run when the action or filter is called.
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*
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* The API callback examples reference functions, but can be methods of classes.
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* To hook methods, you'll need to pass an array one of two ways.
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*
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* For static methods (you won't have access to the <tt>$this</tt> variable in the
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* method):
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* <code>array('class_name', 'method_name');</code>
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*
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* The second method will need the reference to the object to have access to the
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* method.
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* <code>array(&$this, 'method_name');</code>
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* <code>
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* $obj = new myObject();
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* array(&$obj, 'method_name');
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* </code>
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* Any of the syntaxes explained in the PHP documentation for the
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* {@link http://us2.php.net/manual/en/language.pseudo-types.php#language.types.callback 'callback' type} are valid.
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*
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* Also see the {@link http://codex.wordpress.org/Plugin_API Plugin API} for more information
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* and examples on how to use a lot of these functions.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 1.5
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*/
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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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* Filters are the hooks that WordPress launches to modify text of various types
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* before adding it to the database or sending it to the browser screen. Plugins
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* can specify that one or more of its PHP functions is executed to
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* modify specific types of text at these times, using the Filter API.
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*
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* To use the API, the following code should be used to bind a callback to the filter
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* <code>
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* function example_hook($example) { echo $example; }
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*
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* add_filter('example_filter', 'example_hook');
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* </code>
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*
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* In WordPress 1.5.1+, hooked functions can take extra arguments that are set when
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* the matching do_action() or apply_filters() call is run. The <tt>$accepted_args
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* allow for calling functions only when the number of args match. Hooked functions
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* can take extra arguments that are set when the matching <tt>do_action()</tt> or
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* <tt>apply_filters()</tt> call is run. For example, the action <tt>comment_id_not_found</tt>
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* will pass any functions that hook onto it the ID of the requested comment.
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*
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* <strong>Note:</strong> the function will return true no matter if the function was hooked
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* fails or not. There are no checks for whether the function exists beforehand and no checks
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* to whether the <tt>$function_to_add is even a string. It is up to you to take care and
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* this is done for optimization purposes, so everything is as quick as possible.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 1.5
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* @global array $wp_filter Stores all of the filters added in the form of
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* wp_filter['tag']['array of priorities']['array of functions serialized']['array of ['array (functions, accepted_args)]']
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* @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.
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*
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* @param string $tag The name of the filter to hook the <tt>$function_to_add</tt> to.
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* @param callback $function_to_add The name of the function to be called when the filter is applied.
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* @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.
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* @param int $accepted_args optional. The number of arguments the function accept (default 1).
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* @return boolean true
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*/
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function add_filter($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
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global $wp_filter, $merged_filters;
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$idx = _wp_filter_build_unique_id($tag, $function_to_add, $priority, 'filter');
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$wp_filter[$tag][$priority][$idx] = array('function' => $function_to_add, 'accepted_args' => $accepted_args);
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unset( $merged_filters[ $tag ] );
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return true;
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}
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/**
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* Call the functions added to a filter hook.
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*
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* The callback functions attached to filter hook <tt>$tag</tt> are invoked by
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* calling this function. This function can be used to create a new filter hook
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* by simply calling this function with the name of the new hook specified using
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* the <tt>$tag</a> parameter.
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*
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* The function allows for additional arguments to be added and passed to hooks.
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* <code>
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* function example_hook($string, $arg1, $arg2)
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* {
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* //Do stuff
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* }
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* $value = apply_filters('example_filter', 'filter me', 'arg1', 'arg2');
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* </code>
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 1.5
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* @global array $wp_filter Stores all of the filters
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* @global array $merge_filters Merges the filter hooks using this function.
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*
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* @param string $tag The name of the filter hook.
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* @param string $value The value on which the filters hooked to <tt>$tag</tt> are applied on.
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* @param mixed $var,... Additional variables passed to the functions hooked to <tt>$tag</tt>.
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* @return string The text in <tt>$string</tt> after all hooked functions are applied to it.
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*/
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function apply_filters($tag, $value) {
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global $wp_filter, $merged_filters, $wp_current_filter;
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@$wp_current_filter[] = $tag;
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// Do 'all' actions first
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if ( isset($wp_filter['all']) ) {
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reset( $wp_filter['all'] );
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do {
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foreach ( (array) current($wp_filter['all']) as $the_ )
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if ( !is_null($the_['function']) )
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$value = call_user_func_array($the_['function'], $value);
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} while ( next($wp_filter['all']) !== false );
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}
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if ( !isset($wp_filter[$tag]) ) {
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array_pop($wp_current_filter);
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return $value;
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}
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// Sort
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if ( !isset( $merged_filters[ $tag ] ) ) {
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reset($wp_filter[$tag]);
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uksort($wp_filter[$tag], "strnatcasecmp");
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$merged_filters[ $tag ] = true;
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}
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reset( $wp_filter[ $tag ] );
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$args = func_get_args();
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do {
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foreach( (array) current($wp_filter[$tag]) as $the_ )
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if ( !is_null($the_['function']) ){
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$args[1] = $value;
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$value = call_user_func_array($the_['function'], array_slice($args, 1, (int) $the_['accepted_args']));
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}
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} while ( next($wp_filter[$tag]) !== false );
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array_pop( $wp_current_filter );
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return $value;
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}
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/**
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* Removes a function from a specified filter hook.
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*
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* This function removes a function attached to a specified filter hook. This
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* method can be used to remove default functions attached to a specific filter
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* hook and possibly replace them with a substitute.
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*
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* To remove a hook, the <tt>$function_to_remove</tt> and <tt>$priority</tt> arguments
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* must match when the hook was added. This goes for both filters and actions. No warning
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* will be given on removal failure.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 1.5
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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 callback $function_to_remove The name of the function which should be removed.
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* @param int $priority optional. The priority of the function (default: 10).
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* @param int $accepted_args optional. The number of arguments the function accpets (default: 1).
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* @return boolean Whether the function existed before it was removed.
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*/
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function remove_filter($tag, $function_to_remove, $priority = 10, $accepted_args = 1) {
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$function_to_remove = _wp_filter_build_unique_id($tag, $function_to_remove, $priority, 'filter');
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$r = isset($GLOBALS['wp_filter'][$tag][$priority][$function_to_remove]);
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if ( true === $r) {
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unset($GLOBALS['wp_filter'][$tag][$priority][$function_to_remove]);
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unset($GLOBALS['merged_filters'][$tag]);
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}
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return $r;
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}
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/**
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* Return the name of the current filter or action.
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*/
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function current_filter() {
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global $wp_current_filter;
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return end( $wp_current_filter );
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}
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/**
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* Hooks a function on to a specific action.
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*
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* Actions are the hooks that the WordPress core launches at specific points
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* during execution, or when specific events occur. Plugins can specify that
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* one or more of its PHP functions are executed at these points, using the
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* Action API.
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*
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* @uses add_filter() Adds an action. Parameter list and functionality are the same.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 1.5
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*
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* @param string $tag The name of the action to which the <tt>$function_to-add</tt> is hooked.
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* @param callback $function_to_add The name of the function you wish to be called.
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* @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.
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* @param int $accepted_args optional. The number of arguments the function accept (default 1).
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*/
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function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
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global $wp_action, $merged_actions;
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$idx = _wp_filter_build_unique_id($tag, $function_to_add, $priority, 'action');
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$wp_action[$tag][$priority][$idx] = array('function' => $function_to_add, 'accepted_args' => $accepted_args);
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unset( $merged_actions[ $tag ] );
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return true;
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}
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/**
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* Execute functions hooked on a specific action hook.
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*
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* This function invokes all functions attached to action hook <tt>$tag</tt>.
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* It is possible to create new action hooks by simply calling this function,
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* specifying the name of the new hook using the <tt>$tag</tt> parameter.
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*
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* You can pass extra arguments to the hooks, much like you can with apply_filters().
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*
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* @see apply_filters() This function works similar with the exception that nothing is
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* returned and only the functions or methods are called.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 1.5
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* @global array $wp_filter Stores all of the filters
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* @global array $wp_actions Increments the amount of times action was triggered.
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*
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* @param string $tag The name of the action to be executed.
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* @param mixed $arg,... Optional additional arguments which are passed on to the functions hooked to the action.
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* @return null Will return null if $tag does not exist in $wp_filter array
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*/
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function do_action($tag, $arg = '') {
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global $wp_action, $wp_actions, $wp_current_filter;
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if ( is_array($wp_actions) )
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$wp_actions[] = $tag;
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else
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$wp_actions = array($tag);
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$args = array();
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if ( is_array($arg) && 1 == count($arg) && is_object($arg[0]) ) // array(&$this)
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$args[] =& $arg[0];
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else
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$args[] = $arg;
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for ( $a = 2; $a < func_num_args(); $a++ )
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$args[] = func_get_arg($a);
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@$wp_current_filter[] = $tag;
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// Do 'all' actions first
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if ( isset($wp_action['all']) ) {
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do {
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foreach( (array) current($wp_action['all']) as $the_ )
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if ( !is_null($the_['function']) )
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call_user_func_array($the_['function'], $args[0]);
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} while ( next($wp_action['all']) !== false );
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}
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if ( !isset($wp_action[$tag]) ) {
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array_pop($wp_current_filter);
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return;
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}
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// Sort
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if ( !isset( $merged_actions[ $tag ] ) ) {
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reset($wp_action[$tag]);
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uksort($wp_action[$tag], "strnatcasecmp");
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$merged_actions[ $tag ] = true;
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}
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reset( $wp_action[ $tag ] );
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do {
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foreach ( (array) current($wp_action[$tag]) as $the_ )
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if ( !is_null($the_['function']) )
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call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
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} while ( next($wp_action[$tag]) !== false );
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array_pop($wp_current_filter);
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}
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/**
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* Return the number times an action is fired.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 2.1
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* @global array $wp_actions Increments the amount of times action was triggered.
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*
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* @param string $tag The name of the action hook.
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* @return int The number of times action hook <tt>$tag</tt> is fired
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*/
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function did_action($tag) {
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global $wp_actions;
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if ( empty($wp_actions) )
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return 0;
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return count(array_keys($wp_actions, $tag));
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}
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/**
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* Execute functions hooked on a specific action hook, specifying arguments in an array.
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*
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* @see do_action() This function is identical, but the arguments passed to
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* the functions hooked to <tt>$tag</tt> are supplied using an array.
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*
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* @uses merge_filters()
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 2.1
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* @global array $wp_filter Stores all of the filters
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* @global array $wp_actions Increments the amount of times action was triggered.
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*
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* @param string $tag The name of the action to be executed.
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* @param array $args The arguments supplied to the functions hooked to <tt>$tag</tt>
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* @return null Will return null if $tag does not exist in $wp_filter array
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*/
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function do_action_ref_array($tag, $args) {
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global $wp_action, $wp_actions;
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if ( !is_array($wp_actions) )
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$wp_actions = array($tag);
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else
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$wp_actions[] = $tag;
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// Do 'all' actions first
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if ( isset($wp_action['all']) ) {
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do {
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foreach( (array) current($wp_action['all']) as $the_ )
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if ( !is_null($the_['function']) )
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call_user_func_array($the_['function'], $args[0]);
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} while ( next($wp_action['all']) !== false );
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}
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if ( !isset($wp_action[$tag]) )
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return;
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// Sort
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if ( !isset( $merged_actions[ $tag ] ) ) {
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reset($wp_action[$tag]);
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uksort($wp_action[$tag], "strnatcasecmp");
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$merged_actions[ $tag ] = true;
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}
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reset( $wp_action[ $tag ] );
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do {
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foreach( (array) current($wp_action[$tag]) as $the_ )
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if ( !is_null($the_['function']) )
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call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
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} while ( next($wp_action[$tag]) !== false );
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}
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/**
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* Removes a function from a specified action hook.
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*
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* This function removes a function attached to a specified action hook. This
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* method can be used to remove default functions attached to a specific filter
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* hook and possibly replace them with a substitute.
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*
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* @uses remove_filter() Uses remove_filter to remove actions added.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 1.5
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*
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* @param string $tag The action hook to which the function to be removed is hooked.
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* @param callback $function_to_remove The name of the function which should be removed.
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* @param int $priority optional The priority of the function (default: 10).
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* @param int $accepted_args optional. The number of arguments the function accpets (default: 1).
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* @return boolean Whether the function is removed.
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*/
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function remove_action($tag, $function_to_remove, $priority = 10, $accepted_args = 1) {
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$function_to_remove = _wp_filter_build_unique_id($tag, $function_to_remove, $priority, 'action');
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$r = isset($GLOBALS['wp_action'][$tag][$priority][$function_to_remove]);
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if ( true === $r) {
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unset($GLOBALS['wp_action'][$tag][$priority][$function_to_remove]);
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unset($GLOBALS['merged_actions'][$tag]);
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}
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return $r;
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}
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//
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// Functions for handling plugins.
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//
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/**
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* Gets the basename of a plugin.
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*
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* This method extract the name of a plugin from its filename.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 1.5
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*
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* @access private
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*
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* @param string $file The filename of plugin.
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* @return string The name of a plugin.
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*/
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function plugin_basename($file) {
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$file = str_replace('\\','/',$file); // sanitize for Win32 installs
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$file = preg_replace('|/+|','/', $file); // remove any duplicate slash
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$file = preg_replace('|^.*/wp-content/plugins/|','',$file); // get relative path from plugins dir
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return $file;
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}
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/**
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* Hook a function on a plugin activation action hook.
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*
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* When a plugin is activated, the action 'activate_PLUGINNAME' hook is
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* activated. In the name of this hook, PLUGINNAME is replaced with the name of
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* the plugin, including the optional subdirectory. For example, when the plugin
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* is located in <tt>wp-content/plugin/sampleplugin/sample.php</tt>, then the
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* name of this hook will become 'activate_sampleplugin/sample.php'
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* When the plugin consists of only one file and is (as by default) located at
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* <tt>wp-content/plugin/sample.php</tt> the name of this hook will be
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* 'activate_sample.php'.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 1.5
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*
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* @access private
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*
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* @param string $file The filename of the plugin including the path.
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* @param string $function the function hooked to the 'activate_PLUGIN' action.
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*/
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function register_activation_hook($file, $function) {
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$file = plugin_basename($file);
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add_action('activate_' . $file, $function);
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}
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/**
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* Hook a function on a plugin deactivation action hook.
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*
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* When a plugin is deactivated, the action 'deactivate_PLUGINNAME' hook is
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* deactivated. In the name of this hook, PLUGINNAME is replaced with the name of
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* the plugin, including the optional subdirectory. For example, when the plugin
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* is located in <tt>wp-content/plugin/sampleplugin/sample.php</tt>, then the
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* name of this hook will become 'activate_sampleplugin/sample.php'.
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* When the plugin consists of only one file and is (as by default) located at
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* <tt>wp-content/plugin/sample.php</tt> the name of this hook will be
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* 'activate_sample.php'.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 2.0
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*
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* @access private
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*
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* @param string $file The filename of the plugin including the path.
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* @param string $function the function hooked to the 'activate_PLUGIN' action.
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*/
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function register_deactivation_hook($file, $function) {
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$file = plugin_basename($file);
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add_action('deactivate_' . $file, $function);
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}
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/**
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* Build Unique ID for storage and retrieval
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*
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* The old way to serialize the callback caused issues and this function is the
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* solution. It works by checking for objects and creating an a new property in
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* the class to keep track of the object and new objects of the same class that
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* need to be added.
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*
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* It also allows for the removal of actions and filters for objects after they
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* change class properties. It is possible to include the property $wp_filter_id
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* in your class and set it to "null" or a number to bypass the workaround. However
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* this will prevent you from adding new classes and any new classes will overwrite
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* the previous hook by the same class.
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*
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* Functions and static method callbacks are just returned as strings and shouldn't
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* have any speed penalty.
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*
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* @package WordPress
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* @subpackage Plugin
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* @since 2.2.3
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*
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* @link http://trac.wordpress.org/ticket/3875
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*
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* @access private
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*
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* @global array $wp_filter Storage for all of the filters and actions
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* @param string $tag Used in counting how many hooks were applied
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* @param string|array $function Used for creating unique id
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* @param int $priority Used in counting how many hooks were applied
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* @param string $type filter or action
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* @return string Unique ID for usage as array key
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*/
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function _wp_filter_build_unique_id($tag, $function, $priority, $type)
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{
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global $wp_filter, $wp_action;
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// If function then just skip all of the tests and not overwrite the following.
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if ( is_string($function) )
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return $function;
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// Object Class Calling
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else if (is_object($function[0]) ) {
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$obj_idx = get_class($function[0]).$function[1];
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if ( !isset($function[0]->wp_filter_id) ) {
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if ( 'filter' == $type )
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$count = count((array)$wp_filter[$tag][$priority]);
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else
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$count = count((array)$wp_action[$tag][$priority]);
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$function[0]->wp_filter_id = $count;
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$obj_idx .= $count;
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unset($count);
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} else
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$obj_idx .= $function[0]->wp_filter_id;
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return $obj_idx;
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}
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// Static Calling
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else if ( is_string($function[0]) )
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return $function[0].$function[1];
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}
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?>
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