277 lines
12 KiB
PHP
277 lines
12 KiB
PHP
<?php
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/**
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* Hooks a function 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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* See the [Plugin API] for a list of filter hooks.
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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 $accepted_args optional. The number of arguments the function accept (default 1). In WordPress 1.5.1+, hooked functions can take extra arguments that are set when the matching do_action() or apply_filters() call is run.
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* @return boolean true if the <tt>$function_to_add</tt> is added succesfully to filter <tt>$tag</tt>. How many arguments your function takes. In WordPress 1.5.1+, hooked functions can take extra arguments that are set when the matching <tt>do_action()</tt> or <tt>apply_filters()</tt> call is run. For example, the action <tt>comment_id_not_found</tt> will pass any functions that hook onto it the ID of the requested comment.
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*/
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function add_filter($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
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global $wp_filter, $merged_filters;
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// So the format is wp_filter['tag']['array of priorities']['array of functions serialized']['array of ['array (functions, accepted_args)]']
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$wp_filter[$tag][$priority][serialize($function_to_add)] = 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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* @uses merge_filters Merges the filter hooks using this function.
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* @param string $tag The name of the filter hook.
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* @param string $string The text on which the filters hooked to <tt>$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, $string) {
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global $wp_filter, $merged_filters;
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if ( !isset( $merged_filters[ $tag ] ) )
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merge_filters($tag);
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if ( !isset($wp_filter[$tag]) )
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return $string;
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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] = $string;
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$string = 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]) );
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return $string;
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}
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/**
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* Merge the filter functions of a specific filter hook with generic filter functions.
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*
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* It is possible to defined generic filter functions using the filter hook
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* <em>all</e>. These functions are called for every filter tag. This function
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* merges the functions attached to the <em>all</em> hook with the functions
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* of a specific hoook defined by <tt>$tag</tt>.
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* @param string $tag The filter hook of which the functions should be merged.
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*/
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function merge_filters($tag) {
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global $wp_filter, $merged_filters;
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if ( is_array($wp_filter['all']) )
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$wp_filter[$tag] = array_merge($wp_filter['all'], (array) $wp_filter[$tag]);
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if ( isset($wp_filter[$tag]) ){
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reset($wp_filter[$tag]);
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uksort($wp_filter[$tag], "strnatcasecmp");
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}
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$merged_filters[ $tag ] = true;
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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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* @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 $accepted_args optional. The number of arguments the function accpets (default: 1).
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* @return boolean Whether the function is removed.
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*/
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function remove_filter($tag, $function_to_remove, $priority = 10, $accepted_args = 1) {
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global $wp_filter, $merged_filters;
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unset($GLOBALS['wp_filter'][$tag][$priority][serialize($function_to_remove)]);
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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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* 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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* @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. 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.
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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 $accepted_args optional. The number of arguments the function accept (default 1). In WordPress 1.5.1+, hooked functions can take extra arguments that are set when the matching do_action() or apply_filters() call is run.
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* @return boolean Always true.
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*/
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function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
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add_filter($tag, $function_to_add, $priority, $accepted_args);
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}
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/**
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* Execute functions hooked on a specific action hook.
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*
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* This function invokes all functions attached to action hook <tt>$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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* @uses merge_filters
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* @param string $tag The name of the action to be executed.
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* @param mixed $arg,... Optional additional arguments which are passed on to the functions hooked to the action.
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*/
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function do_action($tag, $arg = '') {
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global $wp_filter, $wp_actions;
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$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($a);
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merge_filters($tag);
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if ( !isset($wp_filter[$tag]) )
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return;
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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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call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
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} while ( next($wp_filter[$tag]) );
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if ( is_array($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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}
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/**
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* Return the number of functions hooked to a specific action hook.
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* @param string $tag The name of the action hook.
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* @return int The number of functions hooked to action hook <tt>$tag</tt>
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*/
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function did_action($tag) {
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global $wp_actions;
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return count(array_keys($wp_actions, $tag));
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}
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/**
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* Execute functions hooked on a specific action hook, specifying arguments in a array.
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*
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* This function is identical to {@link do_action}, but the argumetns passe to
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* the functions hooked to <tt>$tag</tt> are supplied using an array.
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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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*/
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function do_action_ref_array($tag, $args) {
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global $wp_filter, $wp_actions;
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if ( !is_array($wp_actions) )
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$wp_actions = array($tag);
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else
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$wp_actions[] = $tag;
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merge_filters($tag);
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if ( !isset($wp_filter[$tag]) )
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return;
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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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call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
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} while ( next($wp_filter[$tag]) );
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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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* @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, $accepted_args = 1) {
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remove_filter($tag, $function_to_remove, $priority, $accepted_args);
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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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* @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 = preg_replace('|\\\\+|', '\\\\', $file);
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$file = preg_replace('/^.*wp-content[\\\\\/]plugins[\\\\\/]/', '', $file);
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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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* @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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* @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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