WordPress/wp-includes/category.php

<?php
/**
 * WordPress Category API
 *
 * @package WordPress
 */

/**
 * Retrieves all category IDs.
 *
 * @since 2.0.0
 * @link http://codex.wordpress.org/Function_Reference/get_all_category_ids
 *
 * @return object List of all of the category IDs.
 */
function get_all_category_ids() {
	if ( ! $cat_ids = wp_cache_get('all_category_ids', 'category') ) {
		$cat_ids = get_terms('category', 'fields=ids&get=all');
		wp_cache_add('all_category_ids', $cat_ids, 'category');
	}

	return $cat_ids;
}

/**
 * Retrieve list of category objects.
 *
 * If you change the type to 'link' in the arguments, then the link categories
 * will be returned instead. Also all categories will be updated to be backwards
 * compatible with pre-2.3 plugins and themes.
 *
 * @since 2.1.0
 * @see get_terms() Type of arguments that can be changed.
 * @link http://codex.wordpress.org/Function_Reference/get_categories
 *
 * @param string|array $args Optional. Change the defaults retrieving categories.
 * @return array List of categories.
 */
function &get_categories($args = '') {
	$defaults = array('type' => 'category');
	$args = wp_parse_args($args, $defaults);

	$taxonomy = 'category';
	if ( 'link' == $args['type'] )
		$taxonomy = 'link_category';
	$categories = get_terms($taxonomy, $args);

	foreach ( array_keys($categories) as $k )
		_make_cat_compat($categories[$k]);

	return $categories;
}

/**
 * Retrieves category data given a category ID or category object.
 *
 * If you pass the $category parameter an object, which is assumed to be the
 * category row object retrieved the database. It will cache the category data.
 *
 * If you pass $category an integer of the category ID, then that category will
 * be retrieved from the database, if it isn't already cached, and pass it back.
 *
 * If you look at get_term(), then both types will be passed through several
 * filters and finally sanitized based on the $filter parameter value.
 *
 * The category will converted to maintain backwards compatibility.
 *
 * @since 2.1.0
 * @uses get_term() Used to get the category data from the taxonomy.
 *
 * @param int|object $category Category ID or Category row object
 * @param string $output Optional. Constant OBJECT, ARRAY_A, or ARRAY_N
 * @param string $filter Optional. Default is raw or no WordPress defined filter will applied.
 * @return mixed Category data in type defined by $output parameter.
 */
function &get_category($category, $output = OBJECT, $filter = 'raw') {
	$category = get_term($category, 'category', $output, $filter);
	if ( is_wp_error( $category ) )
		return $category;

	_make_cat_compat($category);

	return $category;
}

/**
 * Retrieve category based on URL containing the category slug.
 *
 * Breaks the $category_path parameter up to get the category slug.
 *
 * Tries to find the child path and will return it. If it doesn't find a
 * match, then it will return the first category matching slug, if $full_match,
 * is set to false. If it does not, then it will return null.
 *
 * It is also possible that it will return a WP_Error object on failure. Check
 * for it when using this function.
 *
 * @since 2.1.0
 *
 * @param string $category_path URL containing category slugs.
 * @param bool $full_match Optional. Whether should match full path or not.
 * @param string $output Optional. Constant OBJECT, ARRAY_A, or ARRAY_N
 * @return null|object|array Null on failure. Type is based on $output value.
 */
function get_category_by_path($category_path, $full_match = true, $output = OBJECT) {
	$category_path = rawurlencode(urldecode($category_path));
	$category_path = str_replace('%2F', '/', $category_path);
	$category_path = str_replace('%20', ' ', $category_path);
	$category_paths = '/' . trim($category_path, '/');
	$leaf_path  = sanitize_title(basename($category_paths));
	$category_paths = explode('/', $category_paths);
	$full_path = '';
	foreach ( (array) $category_paths as $pathdir )
		$full_path .= ( $pathdir != '' ? '/' : '' ) . sanitize_title($pathdir);

	$categories = get_terms('category', "get=all&slug=$leaf_path");

	if ( empty($categories) )
		return null;

	foreach ($categories as $category) {
		$path = '/' . $leaf_path;
		$curcategory = $category;
		while ( ($curcategory->parent != 0) && ($curcategory->parent != $curcategory->term_id) ) {
			$curcategory = get_term($curcategory->parent, 'category');
			if ( is_wp_error( $curcategory ) )
				return $curcategory;
			$path = '/' . $curcategory->slug . $path;
		}

		if ( $path == $full_path )
			return get_category($category->term_id, $output);
	}

	// If full matching is not required, return the first cat that matches the leaf.
	if ( ! $full_match )
		return get_category($categories[0]->term_id, $output);

	return null;
}

/**
 * Retrieve category object by category slug.
 *
 * @since 2.3.0
 *
 * @param string $slug The category slug.
 * @return object Category data object
 */
function get_category_by_slug( $slug  ) {
	$category = get_term_by('slug', $slug, 'category');
	if ( $category )
		_make_cat_compat($category);

	return $category;
}


/**
 * Retrieve the ID of a category from its name.
 *
 * @since 1.0.0
 *
 * @param string $cat_name Optional. Default is 'General' and can be any category name.
 * @return int 0, if failure and ID of category on success.
 */
function get_cat_ID($cat_name='General') {
	$cat = get_term_by('name', $cat_name, 'category');
	if ($cat)
		return $cat->term_id;
	return 0;
}


/**
 * Retrieve the category name by the category ID.
 *
 * @since 0.71
 * @deprecated Use get_cat_name()
 * @see get_cat_name() get_catname() is deprecated in favor of get_cat_name().
 *
 * @param int $cat_ID Category ID
 * @return string category name
 */
function get_catname($cat_ID) {
	return get_cat_name($cat_ID);
}


/**
 * Retrieve the name of a category from its ID.
 *
 * @since 1.0.0
 *
 * @param int $cat_id Category ID
 * @return string Category name
 */
function get_cat_name($cat_id) {
	$cat_id = (int) $cat_id;
	$category = &get_category($cat_id);
	return $category->name;
}


/**
 * Check if a category is an ancestor of another category.
 *
 * You can use either an id or the category object for both parameters. If you
 * use an integer the category will be retrieved.
 *
 * @since 2.1.0
 *
 * @param int|object $cat1 ID or object to check if this is the parent category.
 * @param int|object $cat2 The child category.
 * @return bool Whether $cat2 is child of $cat1
 */
function cat_is_ancestor_of($cat1, $cat2) {
	if ( is_int($cat1) )
		$cat1 = & get_category($cat1);
	if ( is_int($cat2) )
		$cat2 = & get_category($cat2);

	if ( !$cat1->term_id || !$cat2->parent )
		return false;

	if ( $cat2->parent == $cat1->term_id )
		return true;

	return cat_is_ancestor_of($cat1, get_category($cat2->parent));
}


/**
 * Sanitizes category data based on context.
 *
 * @since 2.3.0
 * @uses sanitize_term() See this function for what context are supported.
 *
 * @param object|array $category Category data
 * @param string $context Optional. Default is 'display'.
 * @return object|array Same type as $category with sanitized data for safe use.
 */
function sanitize_category($category, $context = 'display') {
	return sanitize_term($category, 'category', $context);
}


/**
 * Sanitizes data in single category key field.
 *
 * @since 2.3.0
 * @uses sanitize_term_field() See function for more details.
 *
 * @param string $field Category key to sanitize
 * @param mixed $value Category value to sanitize
 * @param int $cat_id Category ID
 * @param string $context What filter to use, 'raw', 'display', etc.
 * @return mixed Same type as $value after $value has been sanitized.
 */
function sanitize_category_field($field, $value, $cat_id, $context) {
	return sanitize_term_field($field, $value, $cat_id, 'category', $context);
}

/* Tags */


/**
 * Retrieves all post tags.
 *
 * @since 2.3.0
 * @see get_terms() For list of arguments to pass.
 * @uses apply_filters() Calls 'get_tags' hook on array of tags and with $args.
 *
 * @param string|array $args Tag arguments to use when retrieving tags.
 * @return array List of tags.
 */
function &get_tags($args = '') {
	$tags = get_terms('post_tag', $args);

	if ( empty($tags) )
		return array();

	$tags = apply_filters('get_tags', $tags, $args);
	return $tags;
}


/**
 * Retrieve post tag by tag ID or tag object.
 *
 * If you pass the $tag parameter an object, which is assumed to be the tag row
 * object retrieved the database. It will cache the tag data.
 *
 * If you pass $tag an integer of the tag ID, then that tag will
 * be retrieved from the database, if it isn't already cached, and pass it back.
 *
 * If you look at get_term(), then both types will be passed through several
 * filters and finally sanitized based on the $filter parameter value.
 *
 * @since 2.3.0
 *
 * @param int|object $tag
 * @param string $output Optional. Constant OBJECT, ARRAY_A, or ARRAY_N
 * @param string $filter Optional. Default is raw or no WordPress defined filter will applied.
 * @return object|array Return type based on $output value.
 */
function &get_tag($tag, $output = OBJECT, $filter = 'raw') {
	return get_term($tag, 'post_tag', $output, $filter);
}


/* Cache */


/**
 * Update the categories cache.
 *
 * This function does not appear to be used anymore or does not appear to be
 * needed. It might be a legacy function left over from when there was a need
 * for updating the category cache.
 *
 * @since 1.5.0
 *
 * @return bool Always return True
 */
function update_category_cache() {
	return true;
}


/**
 * Remove the category cache data based on ID.
 *
 * @since 2.1.0
 * @uses clean_term_cache() Clears the cache for the category based on ID
 *
 * @param int $id Category ID
 */
function clean_category_cache($id) {
	clean_term_cache($id, 'category');
}


/**
 * Update category structure to old pre 2.3 from new taxonomy structure.
 *
 * This function was added for the taxonomy support to update the new category
 * structure with the old category one. This will maintain compatibility with
 * plugins and themes which depend on the old key or property names.
 *
 * The parameter should only be passed a variable and not create the array or
 * object inline to the parameter. The reason for this is that parameter is
 * passed by reference and PHP will fail unless it has the variable.
 *
 * There is no return value, because everything is updated on the variable you
 * pass to it. This is one of the features with using pass by reference in PHP.
 *
 * @since 2.3.0
 * @access private
 *
 * @param array|object $category Category Row object or array
 */
function _make_cat_compat( &$category) {
	if ( is_object($category) ) {
		$category->cat_ID = &$category->term_id;
		$category->category_count = &$category->count;
		$category->category_description = &$category->description;
		$category->cat_name = &$category->name;
		$category->category_nicename = &$category->slug;
		$category->category_parent = &$category->parent;
	} else if ( is_array($category) && isset($category['term_id']) ) {
		$category['cat_ID'] = &$category['term_id'];
		$category['category_count'] = &$category['count'];
		$category['category_description'] = &$category['description'];
		$category['cat_name'] = &$category['name'];
		$category['category_nicename'] = &$category['slug'];
		$category['category_parent'] = &$category['parent'];
	}
}


?>