web/wp-includes/taxonomy.php
changeset 194 32102edaa81b
parent 136 bde1974c263b
child 204 09a1c134465b
--- a/web/wp-includes/taxonomy.php	Thu Sep 16 15:45:36 2010 +0000
+++ b/web/wp-includes/taxonomy.php	Mon Nov 19 18:26:13 2012 +0100
@@ -12,16 +12,130 @@
 //
 
 /**
- * Creates the initial taxonomies when 'init' action is fired.
+ * Creates the initial taxonomies.
+ *
+ * This function fires twice: in wp-settings.php before plugins are loaded (for
+ * backwards compatibility reasons), and again on the 'init' action. We must avoid
+ * registering rewrite rules before the 'init' action.
  */
 function create_initial_taxonomies() {
-	register_taxonomy( 'category', 'post', array('hierarchical' => true, 'update_count_callback' => '_update_post_term_count', 'label' => __('Categories'), 'query_var' => false, 'rewrite' => false) ) ;
-	register_taxonomy( 'post_tag', 'post', array('hierarchical' => false, 'update_count_callback' => '_update_post_term_count', 'label' => __('Post Tags'), 'query_var' => false, 'rewrite' => false) ) ;
-	register_taxonomy( 'link_category', 'link', array('hierarchical' => false, 'label' => __('Categories'), 'query_var' => false, 'rewrite' => false) ) ;
+	global $wp_rewrite;
+
+	if ( ! did_action( 'init' ) ) {
+		$rewrite = array( 'category' => false, 'post_tag' => false, 'post_format' => false );
+	} else {
+		$post_format_base = apply_filters( 'post_format_rewrite_base', 'type' );
+		$rewrite = array(
+			'category' => array(
+				'hierarchical' => true,
+				'slug' => get_option('category_base') ? get_option('category_base') : 'category',
+				'with_front' => ! get_option('category_base') || $wp_rewrite->using_index_permalinks(),
+				'ep_mask' => EP_CATEGORIES,
+			),
+			'post_tag' => array(
+				'slug' => get_option('tag_base') ? get_option('tag_base') : 'tag',
+				'with_front' => ! get_option('tag_base') || $wp_rewrite->using_index_permalinks(),
+				'ep_mask' => EP_TAGS,
+			),
+			'post_format' => $post_format_base ? array( 'slug' => $post_format_base ) : false,
+		);
+	}
+
+	register_taxonomy( 'category', 'post', array(
+		'hierarchical' => true,
+		'query_var' => 'category_name',
+		'rewrite' => $rewrite['category'],
+		'public' => true,
+		'show_ui' => true,
+		'_builtin' => true,
+	) );
+
+	register_taxonomy( 'post_tag', 'post', array(
+	 	'hierarchical' => false,
+		'query_var' => 'tag',
+		'rewrite' => $rewrite['post_tag'],
+		'public' => true,
+		'show_ui' => true,
+		'_builtin' => true,
+	) );
+
+	register_taxonomy( 'nav_menu', 'nav_menu_item', array(
+		'public' => false,
+		'hierarchical' => false,
+		'labels' => array(
+			'name' => __( 'Navigation Menus' ),
+			'singular_name' => __( 'Navigation Menu' ),
+		),
+		'query_var' => false,
+		'rewrite' => false,
+		'show_ui' => false,
+		'_builtin' => true,
+		'show_in_nav_menus' => false,
+	) );
+
+	register_taxonomy( 'link_category', 'link', array(
+		'hierarchical' => false,
+		'labels' => array(
+			'name' => __( 'Link Categories' ),
+			'singular_name' => __( 'Link Category' ),
+			'search_items' => __( 'Search Link Categories' ),
+			'popular_items' => null,
+			'all_items' => __( 'All Link Categories' ),
+			'edit_item' => __( 'Edit Link Category' ),
+			'update_item' => __( 'Update Link Category' ),
+			'add_new_item' => __( 'Add New Link Category' ),
+			'new_item_name' => __( 'New Link Category Name' ),
+			'separate_items_with_commas' => null,
+			'add_or_remove_items' => null,
+			'choose_from_most_used' => null,
+		),
+		'query_var' => false,
+		'rewrite' => false,
+		'public' => false,
+		'show_ui' => false,
+		'_builtin' => true,
+	) );
+
+	register_taxonomy( 'post_format', 'post', array(
+		'public' => true,
+		'hierarchical' => false,
+		'labels' => array(
+			'name' => _x( 'Format', 'post format' ),
+			'singular_name' => _x( 'Format', 'post format' ),
+		),
+		'query_var' => true,
+		'rewrite' => $rewrite['post_format'],
+		'show_ui' => false,
+		'_builtin' => true,
+		'show_in_nav_menus' => current_theme_supports( 'post-formats' ),
+	) );
 }
 add_action( 'init', 'create_initial_taxonomies', 0 ); // highest priority
 
 /**
+ * Get a list of registered taxonomy objects.
+ *
+ * @package WordPress
+ * @subpackage Taxonomy
+ * @since 3.0.0
+ * @uses $wp_taxonomies
+ * @see register_taxonomy
+ *
+ * @param array $args An array of key => value arguments to match against the taxonomy objects.
+ * @param string $output The type of output to return, either taxonomy 'names' or 'objects'. 'names' is the default.
+ * @param string $operator The logical operation to perform. 'or' means only one element
+ *  from the array needs to match; 'and' means all elements must match. The default is 'and'.
+ * @return array A list of taxonomy names or objects
+ */
+function get_taxonomies( $args = array(), $output = 'names', $operator = 'and' ) {
+	global $wp_taxonomies;
+
+	$field = ('names' == $output) ? 'name' : false;
+
+	return wp_filter_object_list($wp_taxonomies, $args, $operator, $field);
+}
+
+/**
  * Return all of the taxonomy names that are of $object_type.
  *
  * It appears that this function can be used to find all of the names inside of
@@ -37,9 +151,10 @@
  * @uses $wp_taxonomies
  *
  * @param array|string|object $object Name of the type of taxonomy object, or an object (row from posts)
+ * @param string $output The type of output to return, either taxonomy 'names' or 'objects'. 'names' is the default.
  * @return array The names of all taxonomy of $object_type.
  */
-function get_object_taxonomies($object) {
+function get_object_taxonomies($object, $output = 'names') {
 	global $wp_taxonomies;
 
 	if ( is_object($object) ) {
@@ -51,9 +166,13 @@
 	$object = (array) $object;
 
 	$taxonomies = array();
-	foreach ( (array) $wp_taxonomies as $taxonomy ) {
-		if ( array_intersect($object, (array) $taxonomy->object_type) )
-			$taxonomies[] = $taxonomy->name;
+	foreach ( (array) $wp_taxonomies as $tax_name => $tax_obj ) {
+		if ( array_intersect($object, (array) $tax_obj->object_type) ) {
+			if ( 'names' == $output )
+				$taxonomies[] = $tax_name;
+			else
+				$taxonomies[ $tax_name ] = $tax_obj;
+		}
 	}
 
 	return $taxonomies;
@@ -70,7 +189,7 @@
  * @since 2.3.0
  *
  * @uses $wp_taxonomies
- * @uses is_taxonomy() Checks whether taxonomy exists
+ * @uses taxonomy_exists() Checks whether taxonomy exists
  *
  * @param string $taxonomy Name of taxonomy object to return
  * @return object|bool The Taxonomy Object or false if $taxonomy doesn't exist
@@ -78,7 +197,7 @@
 function get_taxonomy( $taxonomy ) {
 	global $wp_taxonomies;
 
-	if ( ! is_taxonomy($taxonomy) )
+	if ( ! taxonomy_exists( $taxonomy ) )
 		return false;
 
 	return $wp_taxonomies[$taxonomy];
@@ -87,19 +206,21 @@
 /**
  * Checks that the taxonomy name exists.
  *
+ * Formerly is_taxonomy(), introduced in 2.3.0.
+ *
  * @package WordPress
  * @subpackage Taxonomy
- * @since 2.3.0
+ * @since 3.0.0
  *
  * @uses $wp_taxonomies
  *
  * @param string $taxonomy Name of taxonomy object
- * @return bool Whether the taxonomy exists or not.
+ * @return bool Whether the taxonomy exists.
  */
-function is_taxonomy( $taxonomy ) {
+function taxonomy_exists( $taxonomy ) {
 	global $wp_taxonomies;
 
-	return isset($wp_taxonomies[$taxonomy]);
+	return isset( $wp_taxonomies[$taxonomy] );
 }
 
 /**
@@ -114,14 +235,14 @@
  * @subpackage Taxonomy
  * @since 2.3.0
  *
- * @uses is_taxonomy() Checks whether taxonomy exists
+ * @uses taxonomy_exists() Checks whether taxonomy exists
  * @uses get_taxonomy() Used to get the taxonomy object
  *
  * @param string $taxonomy Name of taxonomy object
  * @return bool Whether the taxonomy is hierarchical
  */
 function is_taxonomy_hierarchical($taxonomy) {
-	if ( ! is_taxonomy($taxonomy) )
+	if ( ! taxonomy_exists($taxonomy) )
 		return false;
 
 	$taxonomy = get_taxonomy($taxonomy);
@@ -136,16 +257,20 @@
  * parameter), along with strings for the taxonomy name and another string for
  * the object type.
  *
- * Nothing is returned, so expect error maybe or use is_taxonomy() to check
+ * Nothing is returned, so expect error maybe or use taxonomy_exists() to check
  * whether taxonomy exists.
  *
  * Optional $args contents:
  *
- * hierarachical - has some defined purpose at other parts of the API and is a
+ * label - Name of the taxonomy shown in the menu. Usually plural. If not set, labels['name'] will be used.
+ *
+ * hierarchical - has some defined purpose at other parts of the API and is a
  * boolean value.
  *
- * update_count_callback - works much like a hook, in that it will be called
- * when the count is updated.
+ * update_count_callback - works much like a hook, in that it will be called when the count is updated.
+ * 	Defaults to _update_post_term_count() for taxonomies attached to post types, which then confirms
+ * 	that the objects are published before counting them.
+ * 	Defaults to _update_generic_term_count() for taxonomies attached to other object types, such as links.
  *
  * rewrite - false to prevent rewrite, or array('slug'=>$slug) to customize
  * permastruct; default will use $taxonomy as slug.
@@ -153,11 +278,24 @@
  * query_var - false to prevent queries, or string to customize query var
  * (?$query_var=$term); default will use $taxonomy as query var.
  *
+ * public - If the taxonomy should be publicly queryable; //@TODO not implemented.
+ * defaults to true.
+ *
+ * show_ui - If the WordPress UI admin tags UI should apply to this taxonomy;
+ * defaults to public.
+ *
+ * show_in_nav_menus - true makes this taxonomy available for selection in navigation menus.
+ * Defaults to public.
+ *
+ * show_tagcloud - false to prevent the taxonomy being listed in the Tag Cloud Widget;
+ * defaults to show_ui which defaults to public.
+ *
+ * labels - An array of labels for this taxonomy. You can see accepted values in {@link get_taxonomy_labels()}. By default tag labels are used for non-hierarchical types and category labels for hierarchical ones.
+ *
  * @package WordPress
  * @subpackage Taxonomy
  * @since 2.3.0
  * @uses $wp_taxonomies Inserts new taxonomy object into the list
- * @uses $wp_rewrite Adds rewrite tags and permastructs
  * @uses $wp Adds query vars
  *
  * @param string $taxonomy Name of taxonomy object
@@ -165,12 +303,23 @@
  * @param array|string $args See above description for the two keys values.
  */
 function register_taxonomy( $taxonomy, $object_type, $args = array() ) {
-	global $wp_taxonomies, $wp_rewrite, $wp;
-
-	if (!is_array($wp_taxonomies))
+	global $wp_taxonomies, $wp;
+
+	if ( ! is_array($wp_taxonomies) )
 		$wp_taxonomies = array();
 
-	$defaults = array('hierarchical' => false, 'update_count_callback' => '', 'rewrite' => true, 'query_var' => true);
+	$defaults = array(	'hierarchical' => false,
+						'update_count_callback' => '',
+						'rewrite' => true,
+						'query_var' => $taxonomy,
+						'public' => true,
+						'show_ui' => null,
+						'show_tagcloud' => null,
+						'_builtin' => false,
+						'labels' => array(),
+						'capabilities' => array(),
+						'show_in_nav_menus' => null,
+					);
 	$args = wp_parse_args($args, $defaults);
 
 	if ( false !== $args['query_var'] && !empty($wp) ) {
@@ -180,18 +329,134 @@
 		$wp->add_query_var($args['query_var']);
 	}
 
-	if ( false !== $args['rewrite'] && !empty($wp_rewrite) ) {
-		if ( !is_array($args['rewrite']) )
-			$args['rewrite'] = array();
-		if ( !isset($args['rewrite']['slug']) )
-			$args['rewrite']['slug'] = sanitize_title_with_dashes($taxonomy);
-		$wp_rewrite->add_rewrite_tag("%$taxonomy%", '([^/]+)', $args['query_var'] ? "{$args['query_var']}=" : "taxonomy=$taxonomy&term=$term");
-		$wp_rewrite->add_permastruct($taxonomy, "{$args['rewrite']['slug']}/%$taxonomy%");
+	if ( false !== $args['rewrite'] && ( is_admin() || '' != get_option('permalink_structure') ) ) {
+		$args['rewrite'] = wp_parse_args($args['rewrite'], array(
+			'slug' => sanitize_title_with_dashes($taxonomy),
+			'with_front' => true,
+			'hierarchical' => false,
+			'ep_mask' => EP_NONE,
+		));
+
+		if ( $args['hierarchical'] && $args['rewrite']['hierarchical'] )
+			$tag = '(.+?)';
+		else
+			$tag = '([^/]+)';
+
+		add_rewrite_tag( "%$taxonomy%", $tag, $args['query_var'] ? "{$args['query_var']}=" : "taxonomy=$taxonomy&term=" );
+		add_permastruct( $taxonomy, "{$args['rewrite']['slug']}/%$taxonomy%", $args['rewrite'] );
 	}
 
+	if ( is_null($args['show_ui']) )
+		$args['show_ui'] = $args['public'];
+
+	// Whether to show this type in nav-menus.php. Defaults to the setting for public.
+	if ( null === $args['show_in_nav_menus'] )
+		$args['show_in_nav_menus'] = $args['public'];
+
+	if ( is_null($args['show_tagcloud']) )
+		$args['show_tagcloud'] = $args['show_ui'];
+
+	$default_caps = array(
+		'manage_terms' => 'manage_categories',
+		'edit_terms'   => 'manage_categories',
+		'delete_terms' => 'manage_categories',
+		'assign_terms' => 'edit_posts',
+	);
+	$args['cap'] = (object) array_merge( $default_caps, $args['capabilities'] );
+	unset( $args['capabilities'] );
+
 	$args['name'] = $taxonomy;
-	$args['object_type'] = $object_type;
+	$args['object_type'] =  array_unique( (array)$object_type );
+
+	$args['labels'] = get_taxonomy_labels( (object) $args );
+	$args['label'] = $args['labels']->name;
+
 	$wp_taxonomies[$taxonomy] = (object) $args;
+
+	// register callback handling for metabox
+ 	add_filter('wp_ajax_add-' . $taxonomy, '_wp_ajax_add_hierarchical_term');
+
+	do_action( 'registered_taxonomy', $taxonomy, $object_type, $args );
+}
+
+/**
+ * Builds an object with all taxonomy labels out of a taxonomy object
+ *
+ * Accepted keys of the label array in the taxonomy object:
+ * - name - general name for the taxonomy, usually plural. The same as and overridden by $tax->label. Default is Tags/Categories
+ * - singular_name - name for one object of this taxonomy. Default is Tag/Category
+ * - search_items - Default is Search Tags/Search Categories
+ * - popular_items - This string isn't used on hierarchical taxonomies. Default is Popular Tags
+ * - all_items - Default is All Tags/All Categories
+ * - parent_item - This string isn't used on non-hierarchical taxonomies. In hierarchical ones the default is Parent Category
+ * - parent_item_colon - The same as <code>parent_item</code>, but with colon <code>:</code> in the end
+ * - edit_item - Default is Edit Tag/Edit Category
+ * - view_item - Default is View Tag/View Category
+ * - update_item - Default is Update Tag/Update Category
+ * - add_new_item - Default is Add New Tag/Add New Category
+ * - new_item_name - Default is New Tag Name/New Category Name
+ * - separate_items_with_commas - This string isn't used on hierarchical taxonomies. Default is "Separate tags with commas", used in the meta box.
+ * - add_or_remove_items - This string isn't used on hierarchical taxonomies. Default is "Add or remove tags", used in the meta box when JavaScript is disabled.
+ * - choose_from_most_used - This string isn't used on hierarchical taxonomies. Default is "Choose from the most used tags", used in the meta box.
+ *
+ * Above, the first default value is for non-hierarchical taxonomies (like tags) and the second one is for hierarchical taxonomies (like categories).
+ *
+ * @since 3.0.0
+ * @param object $tax Taxonomy object
+ * @return object object with all the labels as member variables
+ */
+
+function get_taxonomy_labels( $tax ) {
+	if ( isset( $tax->helps ) && empty( $tax->labels['separate_items_with_commas'] ) )
+		$tax->labels['separate_items_with_commas'] = $tax->helps;
+
+	$nohier_vs_hier_defaults = array(
+		'name' => array( _x( 'Tags', 'taxonomy general name' ), _x( 'Categories', 'taxonomy general name' ) ),
+		'singular_name' => array( _x( 'Tag', 'taxonomy singular name' ), _x( 'Category', 'taxonomy singular name' ) ),
+		'search_items' => array( __( 'Search Tags' ), __( 'Search Categories' ) ),
+		'popular_items' => array( __( 'Popular Tags' ), null ),
+		'all_items' => array( __( 'All Tags' ), __( 'All Categories' ) ),
+		'parent_item' => array( null, __( 'Parent Category' ) ),
+		'parent_item_colon' => array( null, __( 'Parent Category:' ) ),
+		'edit_item' => array( __( 'Edit Tag' ), __( 'Edit Category' ) ),
+		'view_item' => array( __( 'View Tag' ), __( 'View Category' ) ),
+		'update_item' => array( __( 'Update Tag' ), __( 'Update Category' ) ),
+		'add_new_item' => array( __( 'Add New Tag' ), __( 'Add New Category' ) ),
+		'new_item_name' => array( __( 'New Tag Name' ), __( 'New Category Name' ) ),
+		'separate_items_with_commas' => array( __( 'Separate tags with commas' ), null ),
+		'add_or_remove_items' => array( __( 'Add or remove tags' ), null ),
+		'choose_from_most_used' => array( __( 'Choose from the most used tags' ), null ),
+	);
+	$nohier_vs_hier_defaults['menu_name'] = $nohier_vs_hier_defaults['name'];
+
+	return _get_custom_object_labels( $tax, $nohier_vs_hier_defaults );
+}
+
+/**
+ * Add an already registered taxonomy to an object type.
+ *
+ * @package WordPress
+ * @subpackage Taxonomy
+ * @since 3.0.0
+ * @uses $wp_taxonomies Modifies taxonomy object
+ *
+ * @param string $taxonomy Name of taxonomy object
+ * @param string $object_type Name of the object type
+ * @return bool True if successful, false if not
+ */
+function register_taxonomy_for_object_type( $taxonomy, $object_type) {
+	global $wp_taxonomies;
+
+	if ( !isset($wp_taxonomies[$taxonomy]) )
+		return false;
+
+	if ( ! get_post_type_object($object_type) )
+		return false;
+
+	if ( ! in_array( $object_type, $wp_taxonomies[$taxonomy]->object_type ) )
+		$wp_taxonomies[$taxonomy]->object_type[] = $object_type;
+
+	return true;
 }
 
 //
@@ -220,38 +485,38 @@
  * @uses $wpdb
  * @uses wp_parse_args() Creates an array from string $args.
  *
- * @param string|array $terms String of term or array of string values of terms that will be used
+ * @param int|array $term_ids Term id or array of term ids of terms that will be used
  * @param string|array $taxonomies String of taxonomy name or Array of string values of taxonomy names
  * @param array|string $args Change the order of the object_ids, either ASC or DESC
  * @return WP_Error|array If the taxonomy does not exist, then WP_Error will be returned. On success
  *	the array can be empty meaning that there are no $object_ids found or it will return the $object_ids found.
  */
-function get_objects_in_term( $terms, $taxonomies, $args = array() ) {
+function get_objects_in_term( $term_ids, $taxonomies, $args = array() ) {
 	global $wpdb;
 
-	if ( !is_array( $terms) )
-		$terms = array($terms);
-
-	if ( !is_array($taxonomies) )
-		$taxonomies = array($taxonomies);
+	if ( ! is_array( $term_ids ) )
+		$term_ids = array( $term_ids );
+
+	if ( ! is_array( $taxonomies ) )
+		$taxonomies = array( $taxonomies );
 
 	foreach ( (array) $taxonomies as $taxonomy ) {
-		if ( ! is_taxonomy($taxonomy) )
-			return new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+		if ( ! taxonomy_exists( $taxonomy ) )
+			return new WP_Error( 'invalid_taxonomy', __( 'Invalid taxonomy' ) );
 	}
 
-	$defaults = array('order' => 'ASC');
+	$defaults = array( 'order' => 'ASC' );
 	$args = wp_parse_args( $args, $defaults );
-	extract($args, EXTR_SKIP);
-
-	$order = ( 'desc' == strtolower($order) ) ? 'DESC' : 'ASC';
-
-	$terms = array_map('intval', $terms);
-
-	$taxonomies = "'" . implode("', '", $taxonomies) . "'";
-	$terms = "'" . implode("', '", $terms) . "'";
-
-	$object_ids = $wpdb->get_col("SELECT tr.object_id FROM $wpdb->term_relationships AS tr INNER JOIN $wpdb->term_taxonomy AS tt ON tr.term_taxonomy_id = tt.term_taxonomy_id WHERE tt.taxonomy IN ($taxonomies) AND tt.term_id IN ($terms) ORDER BY tr.object_id $order");
+	extract( $args, EXTR_SKIP );
+
+	$order = ( 'desc' == strtolower( $order ) ) ? 'DESC' : 'ASC';
+
+	$term_ids = array_map('intval', $term_ids );
+
+	$taxonomies = "'" . implode( "', '", $taxonomies ) . "'";
+	$term_ids = "'" . implode( "', '", $term_ids ) . "'";
+
+	$object_ids = $wpdb->get_col("SELECT tr.object_id FROM $wpdb->term_relationships AS tr INNER JOIN $wpdb->term_taxonomy AS tt ON tr.term_taxonomy_id = tt.term_taxonomy_id WHERE tt.taxonomy IN ($taxonomies) AND tt.term_id IN ($term_ids) ORDER BY tr.object_id $order");
 
 	if ( ! $object_ids )
 		return array();
@@ -260,6 +525,287 @@
 }
 
 /**
+ * Given a taxonomy query, generates SQL to be appended to a main query.
+ *
+ * @since 3.1.0
+ *
+ * @see WP_Tax_Query
+ *
+ * @param array $tax_query A compact tax query
+ * @param string $primary_table
+ * @param string $primary_id_column
+ * @return array
+ */
+function get_tax_sql( $tax_query, $primary_table, $primary_id_column ) {
+	$tax_query_obj = new WP_Tax_Query( $tax_query );
+	return $tax_query_obj->get_sql( $primary_table, $primary_id_column );
+}
+
+/**
+ * Container class for a multiple taxonomy query.
+ *
+ * @since 3.1.0
+ */
+class WP_Tax_Query {
+
+	/**
+	 * List of taxonomy queries. A single taxonomy query is an associative array:
+	 * - 'taxonomy' string The taxonomy being queried
+	 * - 'terms' string|array The list of terms
+	 * - 'field' string (optional) Which term field is being used.
+	 *		Possible values: 'term_id', 'slug' or 'name'
+	 *		Default: 'term_id'
+	 * - 'operator' string (optional)
+	 *		Possible values: 'AND', 'IN' or 'NOT IN'.
+	 *		Default: 'IN'
+	 * - 'include_children' bool (optional) Whether to include child terms.
+	 *		Default: true
+	 *
+	 * @since 3.1.0
+	 * @access public
+	 * @var array
+	 */
+	public $queries = array();
+
+	/**
+	 * The relation between the queries. Can be one of 'AND' or 'OR'.
+	 *
+	 * @since 3.1.0
+	 * @access public
+	 * @var string
+	 */
+	public $relation;
+
+	/**
+	 * Standard response when the query should not return any rows.
+	 *
+	 * @since 3.2.0
+	 * @access private
+	 * @var string
+	 */
+	private static $no_results = array( 'join' => '', 'where' => ' AND 0 = 1' );
+
+	/**
+	 * Constructor.
+	 *
+	 * Parses a compact tax query and sets defaults.
+	 *
+	 * @since 3.1.0
+	 * @access public
+	 *
+	 * @param array $tax_query A compact tax query:
+	 *  array(
+	 *    'relation' => 'OR',
+	 *    array(
+	 *      'taxonomy' => 'tax1',
+	 *      'terms' => array( 'term1', 'term2' ),
+	 *      'field' => 'slug',
+	 *    ),
+	 *    array(
+	 *      'taxonomy' => 'tax2',
+	 *      'terms' => array( 'term-a', 'term-b' ),
+	 *      'field' => 'slug',
+	 *    ),
+	 *  )
+	 */
+	public function __construct( $tax_query ) {
+		if ( isset( $tax_query['relation'] ) && strtoupper( $tax_query['relation'] ) == 'OR' ) {
+			$this->relation = 'OR';
+		} else {
+			$this->relation = 'AND';
+		}
+
+		$defaults = array(
+			'taxonomy' => '',
+			'terms' => array(),
+			'include_children' => true,
+			'field' => 'term_id',
+			'operator' => 'IN',
+		);
+
+		foreach ( $tax_query as $query ) {
+			if ( ! is_array( $query ) )
+				continue;
+
+			$query = array_merge( $defaults, $query );
+
+			$query['terms'] = (array) $query['terms'];
+
+			$this->queries[] = $query;
+		}
+	}
+
+	/**
+	 * Generates SQL clauses to be appended to a main query.
+	 *
+	 * @since 3.1.0
+	 * @access public
+	 *
+	 * @param string $primary_table
+	 * @param string $primary_id_column
+	 * @return array
+	 */
+	public function get_sql( $primary_table, $primary_id_column ) {
+		global $wpdb;
+
+		$join = '';
+		$where = array();
+		$i = 0;
+
+		foreach ( $this->queries as $query ) {
+			$this->clean_query( $query );
+
+			if ( is_wp_error( $query ) ) {
+				return self::$no_results;
+			}
+
+			extract( $query );
+
+			if ( 'IN' == $operator ) {
+
+				if ( empty( $terms ) ) {
+					if ( 'OR' == $this->relation )
+						continue;
+					else
+						return self::$no_results;
+				}
+
+				$terms = implode( ',', $terms );
+
+				$alias = $i ? 'tt' . $i : $wpdb->term_relationships;
+
+				$join .= " INNER JOIN $wpdb->term_relationships";
+				$join .= $i ? " AS $alias" : '';
+				$join .= " ON ($primary_table.$primary_id_column = $alias.object_id)";
+
+				$where[] = "$alias.term_taxonomy_id $operator ($terms)";
+			} elseif ( 'NOT IN' == $operator ) {
+
+				if ( empty( $terms ) )
+					continue;
+
+				$terms = implode( ',', $terms );
+
+				$where[] = "$primary_table.$primary_id_column NOT IN (
+					SELECT object_id
+					FROM $wpdb->term_relationships
+					WHERE term_taxonomy_id IN ($terms)
+				)";
+			} elseif ( 'AND' == $operator ) {
+
+				if ( empty( $terms ) )
+					continue;
+
+				$num_terms = count( $terms );
+
+				$terms = implode( ',', $terms );
+
+				$where[] = "(
+					SELECT COUNT(1)
+					FROM $wpdb->term_relationships
+					WHERE term_taxonomy_id IN ($terms)
+					AND object_id = $primary_table.$primary_id_column
+				) = $num_terms";
+			}
+
+			$i++;
+		}
+
+		if ( !empty( $where ) )
+			$where = ' AND ( ' . implode( " $this->relation ", $where ) . ' )';
+		else
+			$where = '';
+
+		return compact( 'join', 'where' );
+	}
+
+	/**
+	 * Validates a single query.
+	 *
+	 * @since 3.2.0
+	 * @access private
+	 *
+	 * @param array &$query The single query
+	 */
+	private function clean_query( &$query ) {
+		if ( ! taxonomy_exists( $query['taxonomy'] ) ) {
+			$query = new WP_Error( 'Invalid taxonomy' );
+			return;
+		}
+
+		$query['terms'] = array_unique( (array) $query['terms'] );
+
+		if ( is_taxonomy_hierarchical( $query['taxonomy'] ) && $query['include_children'] ) {
+			$this->transform_query( $query, 'term_id' );
+
+			if ( is_wp_error( $query ) )
+				return;
+
+			$children = array();
+			foreach ( $query['terms'] as $term ) {
+				$children = array_merge( $children, get_term_children( $term, $query['taxonomy'] ) );
+				$children[] = $term;
+			}
+			$query['terms'] = $children;
+		}
+
+		$this->transform_query( $query, 'term_taxonomy_id' );
+	}
+
+	/**
+	 * Transforms a single query, from one field to another.
+	 *
+	 * @since 3.2.0
+	 * @access private
+	 *
+	 * @param array &$query The single query
+	 * @param string $resulting_field The resulting field
+	 */
+	private function transform_query( &$query, $resulting_field ) {
+		global $wpdb;
+
+		if ( empty( $query['terms'] ) )
+			return;
+
+		if ( $query['field'] == $resulting_field )
+			return;
+
+		$resulting_field = esc_sql( $resulting_field );
+
+		switch ( $query['field'] ) {
+			case 'slug':
+			case 'name':
+				$terms = "'" . implode( "','", array_map( 'sanitize_title_for_query', $query['terms'] ) ) . "'";
+				$terms = $wpdb->get_col( "
+					SELECT $wpdb->term_taxonomy.$resulting_field
+					FROM $wpdb->term_taxonomy
+					INNER JOIN $wpdb->terms USING (term_id)
+					WHERE taxonomy = '{$query['taxonomy']}'
+					AND $wpdb->terms.{$query['field']} IN ($terms)
+				" );
+				break;
+
+			default:
+				$terms = implode( ',', array_map( 'intval', $query['terms'] ) );
+				$terms = $wpdb->get_col( "
+					SELECT $resulting_field
+					FROM $wpdb->term_taxonomy
+					WHERE taxonomy = '{$query['taxonomy']}'
+					AND term_id IN ($terms)
+				" );
+		}
+
+		if ( 'AND' == $query['operator'] && count( $terms ) < count( $query['terms'] ) ) {
+			$query = new WP_Error( 'Inexistent terms' );
+			return;
+		}
+
+		$query['terms'] = $terms;
+		$query['field'] = $resulting_field;
+	}
+}
+
+/**
  * Get all Term data from database by Term ID.
  *
  * The usage of the get_term function is to apply filters to a term object. It
@@ -308,8 +854,8 @@
 		return $error;
 	}
 
-	if ( ! is_taxonomy($taxonomy) ) {
-		$error = new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+	if ( ! taxonomy_exists($taxonomy) ) {
+		$error = new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 		return $error;
 	}
 
@@ -319,9 +865,10 @@
 	} else {
 		if ( is_object($term) )
 			$term = $term->term_id;
-		$term = (int) $term;
+		if ( !$term = (int) $term )
+			return $null;
 		if ( ! $_term = wp_cache_get($term, $taxonomy) ) {
-			$_term = $wpdb->get_row( $wpdb->prepare( "SELECT t.*, tt.* FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy = %s AND t.term_id = %s LIMIT 1", $taxonomy, $term) );
+			$_term = $wpdb->get_row( $wpdb->prepare( "SELECT t.*, tt.* FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy = %s AND t.term_id = %d LIMIT 1", $taxonomy, $term) );
 			if ( ! $_term )
 				return $null;
 			wp_cache_add($term, $_term, $taxonomy);
@@ -375,7 +922,7 @@
 function get_term_by($field, $value, $taxonomy, $output = OBJECT, $filter = 'raw') {
 	global $wpdb;
 
-	if ( ! is_taxonomy($taxonomy) )
+	if ( ! taxonomy_exists($taxonomy) )
 		return false;
 
 	if ( 'slug' == $field ) {
@@ -388,8 +935,10 @@
 		$value = stripslashes($value);
 		$field = 't.name';
 	} else {
-		$field = 't.term_id';
-		$value = (int) $value;
+		$term = get_term( (int) $value, $taxonomy, $output, $filter);
+		if ( is_wp_error( $term ) )
+			$term = false;
+		return $term;
 	}
 
 	$term = $wpdb->get_row( $wpdb->prepare( "SELECT t.*, tt.* FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy = %s AND $field = %s LIMIT 1", $taxonomy, $value) );
@@ -398,6 +947,8 @@
 
 	wp_cache_add($term->term_id, $term, $taxonomy);
 
+	$term = apply_filters('get_term', $term, $taxonomy);
+	$term = apply_filters("get_$taxonomy", $term, $taxonomy);
 	$term = sanitize_term($term, $taxonomy, $filter);
 
 	if ( $output == OBJECT ) {
@@ -427,13 +978,13 @@
  * @uses _get_term_hierarchy()
  * @uses get_term_children() Used to get the children of both $taxonomy and the parent $term
  *
- * @param string $term ID of Term to get children
+ * @param string $term_id ID of Term to get children
  * @param string $taxonomy Taxonomy Name
  * @return array|WP_Error List of Term Objects. WP_Error returned if $taxonomy does not exist
  */
 function get_term_children( $term_id, $taxonomy ) {
-	if ( ! is_taxonomy($taxonomy) )
-		return new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+	if ( ! taxonomy_exists($taxonomy) )
+		return new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 
 	$term_id = intval( $term_id );
 
@@ -530,7 +1081,7 @@
  *
  * The 'get_terms_orderby' filter passes the ORDER BY clause for the query
  * along with the $args array.
-
+ *
  * The 'get_terms_fields' filter passes the fields for the SELECT query
  * along with the $args array.
  *
@@ -545,18 +1096,19 @@
  * hide_empty - Default is true. Will not return empty terms, which means
  * terms whose count is 0 according to the given taxonomy.
  *
- * exclude - Default is an empty string.  A comma- or space-delimited string
- * of term ids to exclude from the return array.  If 'include' is non-empty,
+ * exclude - Default is an empty array. An array, comma- or space-delimited string
+ * of term ids to exclude from the return array. If 'include' is non-empty,
  * 'exclude' is ignored.
  *
- * exclude_tree - A comma- or space-delimited string of term ids to exclude
- * from the return array, along with all of their descendant terms according to
- * the primary taxonomy.  If 'include' is non-empty, 'exclude_tree' is ignored.
+ * exclude_tree - Default is an empty array. An array, comma- or space-delimited
+ * string of term ids to exclude from the return array, along with all of their
+ * descendant terms according to the primary taxonomy. If 'include' is non-empty,
+ * 'exclude_tree' is ignored.
  *
- * include - Default is an empty string.  A comma- or space-delimited string
+ * include - Default is an empty array. An array, comma- or space-delimited string
  * of term ids to include in the return array.
  *
- * number - The maximum number of terms to return.  Default is empty.
+ * number - The maximum number of terms to return. Default is to return them all.
  *
  * offset - The number by which to offset the terms query.
  *
@@ -570,7 +1122,7 @@
  * (even if 'hide_empty' is set to true).
  *
  * search - Returned terms' names will contain the value of 'search',
- * case-insensitive.  Default is an empty string.
+ * case-insensitive. Default is an empty string.
  *
  * name__like - Returned terms' names will begin with the value of 'name__like',
  * case-insensitive. Default is empty string.
@@ -581,19 +1133,24 @@
  * The 'get' argument, if set to 'all' instead of its default empty string,
  * returns terms regardless of ancestry or whether the terms are empty.
  *
- * The 'child_of' argument, when used, should be set to the integer of a term ID.  Its default
- * is 0.  If set to a non-zero value, all returned terms will be descendants
- * of that term according to the given taxonomy.  Hence 'child_of' is set to 0
+ * The 'child_of' argument, when used, should be set to the integer of a term ID. Its default
+ * is 0. If set to a non-zero value, all returned terms will be descendants
+ * of that term according to the given taxonomy. Hence 'child_of' is set to 0
  * if more than one taxonomy is passed in $taxonomies, because multiple taxonomies
  * make term ancestry ambiguous.
  *
- * The 'parent' argument, when used, should be set to the integer of a term ID.  Its default is
+ * The 'parent' argument, when used, should be set to the integer of a term ID. Its default is
  * the empty string '', which has a different meaning from the integer 0.
  * If set to an integer value, all returned terms will have as an immediate
  * ancestor the term whose ID is specified by that integer according to the given taxonomy.
  * The 'parent' argument is different from 'child_of' in that a term X is considered a 'parent'
  * of term Y only if term X is the father of term Y, not its grandfather or great-grandfather, etc.
  *
+ * The 'cache_domain' argument enables a unique cache key to be produced when this query is stored
+ * in object cache. For instance, if you are using one of this function's filters to modify the
+ * query (such as 'terms_clauses'), setting 'cache_domain' to a unique value will not overwrite
+ * the cache for similar queries. Default value is 'core'.
+ *
  * @package WordPress
  * @subpackage Taxonomy
  * @since 2.3.0
@@ -601,7 +1158,7 @@
  * @uses $wpdb
  * @uses wp_parse_args() Merges the defaults with those defined by $args and allows for strings.
  *
- * @param string|array Taxonomy name or list of Taxonomy names
+ * @param string|array $taxonomies Taxonomy name or list of Taxonomy names
  * @param string|array $args The values of what to search for when returning terms
  * @return array|WP_Error List of Term Objects and their children. Will return WP_Error, if any of $taxonomies do not exist.
  */
@@ -615,20 +1172,18 @@
 		$taxonomies = array($taxonomies);
 	}
 
-	foreach ( (array) $taxonomies as $taxonomy ) {
-		if ( ! is_taxonomy($taxonomy) ) {
-			$error = & new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+	foreach ( $taxonomies as $taxonomy ) {
+		if ( ! taxonomy_exists($taxonomy) ) {
+			$error = new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 			return $error;
 		}
 	}
 
-	$in_taxonomies = "'" . implode("', '", $taxonomies) . "'";
-
 	$defaults = array('orderby' => 'name', 'order' => 'ASC',
-		'hide_empty' => true, 'exclude' => '', 'exclude_tree' => '', 'include' => '',
+		'hide_empty' => true, 'exclude' => array(), 'exclude_tree' => array(), 'include' => array(),
 		'number' => '', 'fields' => 'all', 'slug' => '', 'parent' => '',
 		'hierarchical' => true, 'child_of' => 0, 'get' => '', 'name__like' => '',
-		'pad_counts' => false, 'offset' => '', 'search' => '');
+		'pad_counts' => false, 'offset' => '', 'search' => '', 'cache_domain' => 'core' );
 	$args = wp_parse_args( $args, $defaults );
 	$args['number'] = absint( $args['number'] );
 	$args['offset'] = absint( $args['offset'] );
@@ -645,6 +1200,9 @@
 		$args['hierarchical'] = false;
 		$args['pad_counts'] = false;
 	}
+
+	$args = apply_filters( 'get_terms_args', $args, $taxonomies );
+
 	extract($args, EXTR_SKIP);
 
 	if ( $child_of ) {
@@ -683,24 +1241,35 @@
 		$orderby = 't.slug';
 	else if ( 'term_group' == $_orderby )
 		$orderby = 't.term_group';
+	else if ( 'none' == $_orderby )
+		$orderby = '';
 	elseif ( empty($_orderby) || 'id' == $_orderby )
 		$orderby = 't.term_id';
+	else
+		$orderby = 't.name';
 
 	$orderby = apply_filters( 'get_terms_orderby', $orderby, $args );
 
-	$where = '';
+	if ( !empty($orderby) )
+		$orderby = "ORDER BY $orderby";
+	else
+		$order = '';
+
+	$order = strtoupper( $order );
+	if ( '' !== $order && !in_array( $order, array( 'ASC', 'DESC' ) ) )
+		$order = 'ASC';
+
+	$where = "tt.taxonomy IN ('" . implode("', '", $taxonomies) . "')";
 	$inclusions = '';
 	if ( !empty($include) ) {
 		$exclude = '';
 		$exclude_tree = '';
-		$interms = preg_split('/[\s,]+/',$include);
-		if ( count($interms) ) {
-			foreach ( (array) $interms as $interm ) {
-				if (empty($inclusions))
-					$inclusions = ' AND ( t.term_id = ' . intval($interm) . ' ';
-				else
-					$inclusions .= ' OR t.term_id = ' . intval($interm) . ' ';
-			}
+		$interms = wp_parse_id_list($include);
+		foreach ( $interms as $interm ) {
+			if ( empty($inclusions) )
+				$inclusions = ' AND ( t.term_id = ' . intval($interm) . ' ';
+			else
+				$inclusions .= ' OR t.term_id = ' . intval($interm) . ' ';
 		}
 	}
 
@@ -709,24 +1278,12 @@
 	$where .= $inclusions;
 
 	$exclusions = '';
-	if ( ! empty( $exclude_tree ) ) {
-		$excluded_trunks = preg_split('/[\s,]+/',$exclude_tree);
-		foreach( (array) $excluded_trunks as $extrunk ) {
-			$excluded_children = (array) get_terms($taxonomies[0], array('child_of' => intval($extrunk), 'fields' => 'ids'));
+	if ( !empty( $exclude_tree ) ) {
+		$excluded_trunks = wp_parse_id_list($exclude_tree);
+		foreach ( $excluded_trunks as $extrunk ) {
+			$excluded_children = (array) get_terms($taxonomies[0], array('child_of' => intval($extrunk), 'fields' => 'ids', 'hide_empty' => 0));
 			$excluded_children[] = $extrunk;
-			foreach( (array) $excluded_children as $exterm ) {
-				if ( empty($exclusions) )
-					$exclusions = ' AND ( t.term_id <> ' . intval($exterm) . ' ';
-				else
-					$exclusions .= ' AND t.term_id <> ' . intval($exterm) . ' ';
-
-			}
-		}
-	}
-	if ( !empty($exclude) ) {
-		$exterms = preg_split('/[\s,]+/',$exclude);
-		if ( count($exterms) ) {
-			foreach ( (array) $exterms as $exterm ) {
+			foreach( $excluded_children as $exterm ) {
 				if ( empty($exclusions) )
 					$exclusions = ' AND ( t.term_id <> ' . intval($exterm) . ' ';
 				else
@@ -735,6 +1292,16 @@
 		}
 	}
 
+	if ( !empty($exclude) ) {
+		$exterms = wp_parse_id_list($exclude);
+		foreach ( $exterms as $exterm ) {
+			if ( empty($exclusions) )
+				$exclusions = ' AND ( t.term_id <> ' . intval($exterm) . ' ';
+			else
+				$exclusions .= ' AND t.term_id <> ' . intval($exterm) . ' ';
+		}
+	}
+
 	if ( !empty($exclusions) )
 		$exclusions .= ')';
 	$exclusions = apply_filters('list_terms_exclusions', $exclusions, $args );
@@ -745,8 +1312,10 @@
 		$where .= " AND t.slug = '$slug'";
 	}
 
-	if ( !empty($name__like) )
-		$where .= " AND t.name LIKE '{$name__like}%'";
+	if ( !empty($name__like) ) {
+		$name__like = like_escape( $name__like );
+		$where .= $wpdb->prepare( " AND t.name LIKE %s", $name__like . '%' );
+	}
 
 	if ( '' !== $parent ) {
 		$parent = (int) $parent;
@@ -758,29 +1327,56 @@
 
 	// don't limit the query results when we have to descend the family tree
 	if ( ! empty($number) && ! $hierarchical && empty( $child_of ) && '' === $parent ) {
-		if( $offset )
-			$limit = 'LIMIT ' . $offset . ',' . $number;
+		if ( $offset )
+			$limits = 'LIMIT ' . $offset . ',' . $number;
 		else
-			$limit = 'LIMIT ' . $number;
-
-	} else
-		$limit = '';
+			$limits = 'LIMIT ' . $number;
+	} else {
+		$limits = '';
+	}
 
 	if ( !empty($search) ) {
 		$search = like_escape($search);
-		$where .= " AND (t.name LIKE '%$search%')";
+		$where .= $wpdb->prepare( " AND (t.name LIKE %s)", '%' . $search . '%');
 	}
 
 	$selects = array();
-	if ( 'all' == $fields )
-		$selects = array('t.*', 'tt.*');
-	else if ( 'ids' == $fields )
-		$selects = array('t.term_id', 'tt.parent', 'tt.count');
-	else if ( 'names' == $fields )
-		$selects = array('t.term_id', 'tt.parent', 'tt.count', 't.name');
-        $select_this = implode(', ', apply_filters( 'get_terms_fields', $selects, $args ));
-
-	$query = "SELECT $select_this FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy IN ($in_taxonomies) $where ORDER BY $orderby $order $limit";
+	switch ( $fields ) {
+		case 'all':
+			$selects = array('t.*', 'tt.*');
+			break;
+		case 'ids':
+		case 'id=>parent':
+			$selects = array('t.term_id', 'tt.parent', 'tt.count');
+			break;
+		case 'names':
+			$selects = array('t.term_id', 'tt.parent', 'tt.count', 't.name');
+			break;
+		case 'count':
+			$orderby = '';
+			$order = '';
+			$selects = array('COUNT(*)');
+	}
+
+	$_fields = $fields;
+
+	$fields = implode(', ', apply_filters( 'get_terms_fields', $selects, $args ));
+
+	$join = "INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id";
+
+	$pieces = array( 'fields', 'join', 'where', 'orderby', 'order', 'limits' );
+	$clauses = apply_filters( 'terms_clauses', compact( $pieces ), $taxonomies, $args );
+	foreach ( $pieces as $piece )
+		$$piece = isset( $clauses[ $piece ] ) ? $clauses[ $piece ] : '';
+
+	$query = "SELECT $fields FROM $wpdb->terms AS t $join WHERE $where $orderby $order $limits";
+
+	$fields = $_fields;
+
+	if ( 'count' == $fields ) {
+		$term_count = $wpdb->get_var($query);
+		return $term_count;
+	}
 
 	$terms = $wpdb->get_results($query);
 	if ( 'all' == $fields ) {
@@ -788,7 +1384,7 @@
 	}
 
 	if ( empty($terms) ) {
-		wp_cache_add( $cache_key, array(), 'terms' );
+		wp_cache_add( $cache_key, array(), 'terms', 86400 ); // one day
 		$terms = apply_filters('get_terms', array(), $taxonomies, $args);
 		return $terms;
 	}
@@ -808,7 +1404,7 @@
 		foreach ( $terms as $k => $term ) {
 			if ( ! $term->count ) {
 				$children = _get_term_children($term->term_id, $terms, $taxonomies[0]);
-				if( is_array($children) )
+				if ( is_array($children) )
 					foreach ( $children as $child )
 						if ( $child->count )
 							continue 2;
@@ -821,7 +1417,11 @@
 	reset ( $terms );
 
 	$_terms = array();
-	if ( 'ids' == $fields ) {
+	if ( 'id=>parent' == $fields ) {
+		while ( $term = array_shift($terms) )
+			$_terms[$term->term_id] = $term->parent;
+		$terms = $_terms;
+	} elseif ( 'ids' == $fields ) {
 		while ( $term = array_shift($terms) )
 			$_terms[] = $term->term_id;
 		$terms = $_terms;
@@ -835,7 +1435,7 @@
 		$terms = array_slice($terms, $offset, $number);
 	}
 
-	wp_cache_add( $cache_key, $terms, 'terms' );
+	wp_cache_add( $cache_key, $terms, 'terms', 86400 ); // one day
 
 	$terms = apply_filters('get_terms', $terms, $taxonomies, $args);
 	return $terms;
@@ -844,20 +1444,21 @@
 /**
  * Check if Term exists.
  *
- * Returns the index of a defined term, or 0 (false) if the term doesn't exist.
+ * Formerly is_term(), introduced in 2.3.0.
  *
  * @package WordPress
  * @subpackage Taxonomy
- * @since 2.3.0
+ * @since 3.0.0
  *
  * @uses $wpdb
  *
  * @param int|string $term The term to check
  * @param string $taxonomy The taxonomy name to use
  * @param int $parent ID of parent term under which to confine the exists search.
- * @return mixed Get the term id or Term Object, if exists.
+ * @return mixed Returns 0 if the term does not exist. Returns the term ID if no taxonomy is specified
+ * 	and the term ID exists. Returns an array of the term ID and the taxonomy if the pairing exists.
  */
-function is_term($term, $taxonomy = '', $parent = 0) {
+function term_exists($term, $taxonomy = '', $parent = 0) {
 	global $wpdb;
 
 	$select = "SELECT term_id FROM $wpdb->terms as t WHERE ";
@@ -907,9 +1508,35 @@
 }
 
 /**
+ * Check if a term is an ancestor of another term.
+ *
+ * You can use either an id or the term object for both parameters.
+ *
+ * @since 3.4.0
+ *
+ * @param int|object $term1 ID or object to check if this is the parent term.
+ * @param int|object $term2 The child term.
+ * @param string $taxonomy Taxonomy name that $term1 and $term2 belong to.
+ * @return bool Whether $term2 is child of $term1
+ */
+function term_is_ancestor_of( $term1, $term2, $taxonomy ) {
+	if ( ! isset( $term1->term_id ) )
+		$term1 = get_term( $term1, $taxonomy );
+	if ( ! isset( $term2->parent ) )
+		$term2 = get_term( $term2, $taxonomy );
+
+	if ( empty( $term1->term_id ) || empty( $term2->parent ) )
+		return false;
+	if ( $term2->parent == $term1->term_id )
+		return true;
+
+	return term_is_ancestor_of( $term1, get_term( $term2->parent, $taxonomy ), $taxonomy );
+}
+
+/**
  * Sanitize Term all fields.
  *
- * Relys on sanitize_term_field() to sanitize the term. The difference is that
+ * Relies on sanitize_term_field() to sanitize the term. The difference is that
  * this function will sanitize <strong>all</strong> fields. The context is based
  * on sanitize_term_field().
  *
@@ -994,26 +1621,26 @@
 		return $value;
 
 	if ( 'edit' == $context ) {
-		$value = apply_filters("edit_term_$field", $value, $term_id, $taxonomy);
-		$value = apply_filters("edit_${taxonomy}_$field", $value, $term_id);
+		$value = apply_filters("edit_term_{$field}", $value, $term_id, $taxonomy);
+		$value = apply_filters("edit_{$taxonomy}_{$field}", $value, $term_id);
 		if ( 'description' == $field )
-			$value = format_to_edit($value);
+			$value = esc_html($value); // textarea_escaped
 		else
 			$value = esc_attr($value);
 	} else if ( 'db' == $context ) {
-		$value = apply_filters("pre_term_$field", $value, $taxonomy);
-		$value = apply_filters("pre_${taxonomy}_$field", $value);
+		$value = apply_filters("pre_term_{$field}", $value, $taxonomy);
+		$value = apply_filters("pre_{$taxonomy}_{$field}", $value);
 		// Back compat filters
 		if ( 'slug' == $field )
 			$value = apply_filters('pre_category_nicename', $value);
 
 	} else if ( 'rss' == $context ) {
-		$value = apply_filters("term_${field}_rss", $value, $taxonomy);
-		$value = apply_filters("${taxonomy}_${field}_rss", $value);
+		$value = apply_filters("term_{$field}_rss", $value, $taxonomy);
+		$value = apply_filters("{$taxonomy}_{$field}_rss", $value);
 	} else {
 		// Use display filters by default.
-		$value = apply_filters("term_$field", $value, $term_id, $taxonomy, $context);
-		$value = apply_filters("${taxonomy}_$field", $value, $term_id, $context);
+		$value = apply_filters("term_{$field}", $value, $term_id, $taxonomy, $context);
+		$value = apply_filters("{$taxonomy}_{$field}", $value, $term_id, $context);
 	}
 
 	if ( 'attribute' == $context )
@@ -1027,40 +1654,40 @@
 /**
  * Count how many terms are in Taxonomy.
  *
- * Default $args is 'ignore_empty' which can be <code>'ignore_empty=true'</code>
- * or <code>array('ignore_empty' => true);</code>.
+ * Default $args is 'hide_empty' which can be 'hide_empty=true' or array('hide_empty' => true).
  *
  * @package WordPress
  * @subpackage Taxonomy
  * @since 2.3.0
  *
- * @uses $wpdb
+ * @uses get_terms()
  * @uses wp_parse_args() Turns strings into arrays and merges defaults into an array.
  *
  * @param string $taxonomy Taxonomy name
- * @param array|string $args Overwrite defaults
+ * @param array|string $args Overwrite defaults. See get_terms()
  * @return int How many terms are in $taxonomy
  */
 function wp_count_terms( $taxonomy, $args = array() ) {
-	global $wpdb;
-
-	$defaults = array('ignore_empty' => false);
+	$defaults = array('hide_empty' => false);
 	$args = wp_parse_args($args, $defaults);
-	extract($args, EXTR_SKIP);
-
-	$where = '';
-	if ( $ignore_empty )
-		$where = 'AND count > 0';
-
-	return $wpdb->get_var( $wpdb->prepare("SELECT COUNT(*) FROM $wpdb->term_taxonomy WHERE taxonomy = %s $where", $taxonomy) );
+
+	// backwards compatibility
+	if ( isset($args['ignore_empty']) ) {
+		$args['hide_empty'] = $args['ignore_empty'];
+		unset($args['ignore_empty']);
+	}
+
+	$args['fields'] = 'count';
+
+	return get_terms($taxonomy, $args);
 }
 
 /**
- * Will unlink the term from the taxonomy.
+ * Will unlink the object from the taxonomy or taxonomies.
  *
- * Will remove the term's relationship to the taxonomy, not the term or taxonomy
- * itself. The term and taxonomy will still exist. Will require the term's
- * object ID to perform the operation.
+ * Will remove all relationships between the object and any terms in
+ * a particular taxonomy or taxonomies. Does not remove the term or
+ * taxonomy itself.
  *
  * @package WordPress
  * @subpackage Taxonomy
@@ -1068,7 +1695,7 @@
  * @uses $wpdb
  *
  * @param int $object_id The term Object Id that refers to the term
- * @param string|array $taxonomy List of Taxonomy Names or single Taxonomy name.
+ * @param string|array $taxonomies List of Taxonomy Names or single Taxonomy name.
  */
 function wp_delete_object_term_relationships( $object_id, $taxonomies ) {
 	global $wpdb;
@@ -1079,7 +1706,7 @@
 		$taxonomies = array($taxonomies);
 
 	foreach ( (array) $taxonomies as $taxonomy ) {
-		$tt_ids = wp_get_object_terms($object_id, $taxonomy, 'fields=tt_ids');
+		$tt_ids = wp_get_object_terms($object_id, $taxonomy, array('fields' => 'tt_ids'));
 		$in_tt_ids = "'" . implode("', '", $tt_ids) . "'";
 		do_action( 'delete_term_relationships', $object_id, $tt_ids );
 		$wpdb->query( $wpdb->prepare("DELETE FROM $wpdb->term_relationships WHERE object_id = %d AND term_taxonomy_id IN ($in_tt_ids)", $object_id) );
@@ -1118,7 +1745,7 @@
 
 	$term = (int) $term;
 
-	if ( ! $ids = is_term($term, $taxonomy) )
+	if ( ! $ids = term_exists($term, $taxonomy) )
 		return false;
 	if ( is_wp_error( $ids ) )
 		return $ids;
@@ -1126,12 +1753,19 @@
 	$tt_id = $ids['term_taxonomy_id'];
 
 	$defaults = array();
+
+	if ( 'category' == $taxonomy ) {
+		$defaults['default'] = get_option( 'default_category' );
+		if ( $defaults['default'] == $term )
+			return 0; // Don't delete the default category
+	}
+
 	$args = wp_parse_args($args, $defaults);
 	extract($args, EXTR_SKIP);
 
-	if ( isset($default) ) {
+	if ( isset( $default ) ) {
 		$default = (int) $default;
-		if ( ! is_term($default, $taxonomy) )
+		if ( ! term_exists($default, $taxonomy) )
 			unset($default);
 	}
 
@@ -1163,13 +1797,18 @@
 		wp_set_object_terms($object, $terms, $taxonomy);
 	}
 
+	// Clean the relationship caches for all object types using this term
+	$tax_object = get_taxonomy( $taxonomy );
+	foreach ( $tax_object->object_type as $object_type )
+		clean_object_term_cache( $objects, $object_type );
+
 	do_action( 'delete_term_taxonomy', $tt_id );
-	$wpdb->query( $wpdb->prepare( "DELETE FROM $wpdb->term_taxonomy WHERE term_taxonomy_id = %d", $tt_id ) );
+	$wpdb->delete( $wpdb->term_taxonomy, array( 'term_taxonomy_id' => $tt_id ) );
 	do_action( 'deleted_term_taxonomy', $tt_id );
 
 	// Delete the term if no taxonomies use it.
 	if ( !$wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->term_taxonomy WHERE term_id = %d", $term) ) )
-		$wpdb->query( $wpdb->prepare( "DELETE FROM $wpdb->terms WHERE term_id = %d", $term) );
+		$wpdb->delete( $wpdb->terms, array( 'term_id' => $term ) );
 
 	clean_term_cache($term, $taxonomy);
 
@@ -1180,6 +1819,20 @@
 }
 
 /**
+ * Deletes one existing category.
+ *
+ * @since 2.0.0
+ * @uses wp_delete_term()
+ *
+ * @param int $cat_ID
+ * @return mixed Returns true if completes delete action; false if term doesn't exist;
+ * 	Zero on attempted deletion of default Category; WP_Error object is also a possibility.
+ */
+function wp_delete_category( $cat_ID ) {
+	return wp_delete_term( $cat_ID, 'category' );
+}
+
+/**
  * Retrieves the terms associated with the given object(s), in the supplied taxonomies.
  *
  * The following information has to do the $args parameter and for what can be
@@ -1197,7 +1850,7 @@
  * 'all_with_object_id'.
  *
  * The fields argument also decides what will be returned. If 'all' or
- * 'all_with_object_id' is choosen or the default kept intact, then all matching
+ * 'all_with_object_id' is chosen or the default kept intact, then all matching
  * terms objects will be returned. If either 'ids' or 'names' is used, then an
  * array of all matching term ids or term names will be returned respectively.
  *
@@ -1206,20 +1859,23 @@
  * @since 2.3.0
  * @uses $wpdb
  *
- * @param int|array $object_id The id of the object(s) to retrieve.
+ * @param int|array $object_ids The ID(s) of the object(s) to retrieve.
  * @param string|array $taxonomies The taxonomies to retrieve terms from.
  * @param array|string $args Change what is returned
- * @return array|WP_Error The requested term data or empty array if no terms found. WP_Error if $taxonomy does not exist.
+ * @return array|WP_Error The requested term data or empty array if no terms found. WP_Error if any of the $taxonomies don't exist.
  */
 function wp_get_object_terms($object_ids, $taxonomies, $args = array()) {
 	global $wpdb;
 
+	if ( empty( $object_ids ) || empty( $taxonomies ) )
+		return array();
+
 	if ( !is_array($taxonomies) )
 		$taxonomies = array($taxonomies);
 
 	foreach ( (array) $taxonomies as $taxonomy ) {
-		if ( ! is_taxonomy($taxonomy) )
-			return new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+		if ( ! taxonomy_exists($taxonomy) )
+			return new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 	}
 
 	if ( !is_array($object_ids) )
@@ -1270,6 +1926,10 @@
 	if ( !empty($orderby) )
 		$orderby = "ORDER BY $orderby";
 
+	$order = strtoupper( $order );
+	if ( '' !== $order && ! in_array( $order, array( 'ASC', 'DESC' ) ) )
+		$order = 'ASC';
+
 	$taxonomies = "'" . implode("', '", $taxonomies) . "'";
 	$object_ids = implode(', ', $object_ids);
 
@@ -1280,6 +1940,8 @@
 		$select_this = 't.term_id';
 	else if ( 'names' == $fields )
 		$select_this = 't.name';
+	else if ( 'slugs' == $fields )
+		$select_this = 't.slug';
 	else if ( 'all_with_object_id' == $fields )
 		$select_this = 't.*, tt.*, tr.object_id';
 
@@ -1288,7 +1950,7 @@
 	if ( 'all' == $fields || 'all_with_object_id' == $fields ) {
 		$terms = array_merge($terms, $wpdb->get_results($query));
 		update_term_cache($terms);
-	} else if ( 'ids' == $fields || 'names' == $fields ) {
+	} else if ( 'ids' == $fields || 'names' == $fields || 'slugs' == $fields ) {
 		$terms = array_merge($terms, $wpdb->get_col($query));
 	} else if ( 'tt_ids' == $fields ) {
 		$terms = $wpdb->get_col("SELECT tr.term_taxonomy_id FROM $wpdb->term_relationships AS tr INNER JOIN $wpdb->term_taxonomy AS tt ON tr.term_taxonomy_id = tt.term_taxonomy_id WHERE tr.object_id IN ($object_ids) AND tt.taxonomy IN ($taxonomies) $orderby $order");
@@ -1303,7 +1965,7 @@
 /**
  * Adds a new term to the database. Optionally marks it as an alias of an existing term.
  *
- * Error handling is assigned for the nonexistance of the $taxonomy and $term
+ * Error handling is assigned for the nonexistence of the $taxonomy and $term
  * parameters before inserting. If both the term id and taxonomy exist
  * previously, then an array will be returned that contains the term id and the
  * contents of what is returned. The keys of the array are 'term_id' and
@@ -1341,13 +2003,14 @@
  * @since 2.3.0
  * @uses $wpdb
  *
+ * @uses apply_filters() Calls 'pre_insert_term' hook with term and taxonomy as parameters.
  * @uses do_action() Calls 'create_term' hook with the term id and taxonomy id as parameters.
  * @uses do_action() Calls 'create_$taxonomy' hook with term id and taxonomy id as parameters.
  * @uses apply_filters() Calls 'term_id_filter' hook with term id and taxonomy id as parameters.
  * @uses do_action() Calls 'created_term' hook with the term id and taxonomy id as parameters.
  * @uses do_action() Calls 'created_$taxonomy' hook with term id and taxonomy id as parameters.
  *
- * @param int|string $term The term to add or update.
+ * @param string $term The term to add or update.
  * @param string $taxonomy The taxonomy to which to add the term
  * @param array|string $args Change the values of the inserted term
  * @return array|WP_Error The Term ID and Term Taxonomy ID
@@ -1355,9 +2018,13 @@
 function wp_insert_term( $term, $taxonomy, $args = array() ) {
 	global $wpdb;
 
-	if ( ! is_taxonomy($taxonomy) )
+	if ( ! taxonomy_exists($taxonomy) )
 		return new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 
+	$term = apply_filters( 'pre_insert_term', $term, $taxonomy );
+		if ( is_wp_error( $term ) )
+			return $term;
+
 	if ( is_int($term) && 0 == $term )
 		return new WP_Error('invalid_term_id', __('Invalid term ID'));
 
@@ -1393,19 +2060,39 @@
 		}
 	}
 
-	if ( ! $term_id = is_term($slug) ) {
-		if ( false === $wpdb->insert( $wpdb->terms, compact( 'name', 'slug', 'term_group' ) ) )
-			return new WP_Error('db_insert_error', __('Could not insert term into the database'), $wpdb->last_error);
-		$term_id = (int) $wpdb->insert_id;
-	} else if ( is_taxonomy_hierarchical($taxonomy) && !empty($parent) ) {
-		// If the taxonomy supports hierarchy and the term has a parent, make the slug unique
-		// by incorporating parent slugs.
+	if ( $term_id = term_exists($slug) ) {
+		$existing_term = $wpdb->get_row( $wpdb->prepare( "SELECT name FROM $wpdb->terms WHERE term_id = %d", $term_id), ARRAY_A );
+		// We've got an existing term in the same taxonomy, which matches the name of the new term:
+		if ( is_taxonomy_hierarchical($taxonomy) && $existing_term['name'] == $name && $exists = term_exists( (int) $term_id, $taxonomy ) ) {
+			// Hierarchical, and it matches an existing term, Do not allow same "name" in the same level.
+			$siblings = get_terms($taxonomy, array('fields' => 'names', 'get' => 'all', 'parent' => (int)$parent) );
+			if ( in_array($name, $siblings) ) {
+				return new WP_Error('term_exists', __('A term with the name provided already exists with this parent.'), $exists['term_id']);
+			} else {
+				$slug = wp_unique_term_slug($slug, (object) $args);
+				if ( false === $wpdb->insert( $wpdb->terms, compact( 'name', 'slug', 'term_group' ) ) )
+					return new WP_Error('db_insert_error', __('Could not insert term into the database'), $wpdb->last_error);
+				$term_id = (int) $wpdb->insert_id;
+			}
+		} elseif ( $existing_term['name'] != $name ) {
+			// We've got an existing term, with a different name, Create the new term.
+			$slug = wp_unique_term_slug($slug, (object) $args);
+			if ( false === $wpdb->insert( $wpdb->terms, compact( 'name', 'slug', 'term_group' ) ) )
+				return new WP_Error('db_insert_error', __('Could not insert term into the database'), $wpdb->last_error);
+			$term_id = (int) $wpdb->insert_id;
+		} elseif ( $exists = term_exists( (int) $term_id, $taxonomy ) )  {
+			// Same name, same slug.
+			return new WP_Error('term_exists', __('A term with the name provided already exists.'), $exists['term_id']);
+		}
+	} else {
+		// This term does not exist at all in the database, Create it.
 		$slug = wp_unique_term_slug($slug, (object) $args);
 		if ( false === $wpdb->insert( $wpdb->terms, compact( 'name', 'slug', 'term_group' ) ) )
 			return new WP_Error('db_insert_error', __('Could not insert term into the database'), $wpdb->last_error);
 		$term_id = (int) $wpdb->insert_id;
 	}
 
+	// Seems unreachable, However, Is used in the case that a term name is provided, which sanitizes to an empty string.
 	if ( empty($slug) ) {
 		$slug = sanitize_title($slug, $term_id);
 		do_action( 'edit_terms', $term_id );
@@ -1451,7 +2138,7 @@
  * @uses $wpdb
  *
  * @param int $object_id The object to relate to.
- * @param array|int|string $term The slug or id of the term, will replace all existing
+ * @param array|int|string $terms The slug or id of the term, will replace all existing
  * related terms in this taxonomy.
  * @param array|string $taxonomy The context in which to relate the term to the object.
  * @param bool $append If false will delete difference of terms.
@@ -1462,24 +2149,31 @@
 
 	$object_id = (int) $object_id;
 
-	if ( ! is_taxonomy($taxonomy) )
-		return new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+	if ( ! taxonomy_exists($taxonomy) )
+		return new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 
 	if ( !is_array($terms) )
 		$terms = array($terms);
 
 	if ( ! $append )
 		$old_tt_ids =  wp_get_object_terms($object_id, $taxonomy, array('fields' => 'tt_ids', 'orderby' => 'none'));
+	else
+		$old_tt_ids = array();
 
 	$tt_ids = array();
 	$term_ids = array();
+	$new_tt_ids = array();
 
 	foreach ( (array) $terms as $term) {
 		if ( !strlen(trim($term)) )
 			continue;
 
-		if ( !$term_info = is_term($term, $taxonomy) )
+		if ( !$term_info = term_exists($term, $taxonomy) ) {
+			// Skip if a non-existent term ID is passed.
+			if ( is_int($term) )
+				continue;
 			$term_info = wp_insert_term($term, $taxonomy);
+		}
 		if ( is_wp_error($term_info) )
 			return $term_info;
 		$term_ids[] = $term_info['term_id'];
@@ -1491,9 +2185,11 @@
 		do_action( 'add_term_relationship', $object_id, $tt_id );
 		$wpdb->insert( $wpdb->term_relationships, array( 'object_id' => $object_id, 'term_taxonomy_id' => $tt_id ) );
 		do_action( 'added_term_relationship', $object_id, $tt_id );
+		$new_tt_ids[] = $tt_id;
 	}
 
-	wp_update_term_count($tt_ids, $taxonomy);
+	if ( $new_tt_ids )
+		wp_update_term_count( $new_tt_ids, $taxonomy );
 
 	if ( ! $append ) {
 		$delete_terms = array_diff($old_tt_ids, $tt_ids);
@@ -1510,7 +2206,7 @@
 	if ( ! $append && isset($t->sort) && $t->sort ) {
 		$values = array();
 		$term_order = 0;
-		$final_tt_ids = wp_get_object_terms($object_id, $taxonomy, 'fields=tt_ids');
+		$final_tt_ids = wp_get_object_terms($object_id, $taxonomy, array('fields' => 'tt_ids'));
 		foreach ( $tt_ids as $tt_id )
 			if ( in_array($tt_id, $final_tt_ids) )
 				$values[] = $wpdb->prepare( "(%d, %d, %d)", $object_id, $tt_id, ++$term_order);
@@ -1530,10 +2226,10 @@
  * slug has to be globally unique for every taxonomy.
  *
  * The way this works is that if the taxonomy that the term belongs to is
- * heirarchical and has a parent, it will append that parent to the $slug.
+ * hierarchical and has a parent, it will append that parent to the $slug.
  *
  * If that still doesn't return an unique slug, then it try to append a number
- * until it finds a number that is truely unique.
+ * until it finds a number that is truly unique.
  *
  * The only purpose for $term is for appending a parent, if one exists.
  *
@@ -1549,6 +2245,9 @@
 function wp_unique_term_slug($slug, $term) {
 	global $wpdb;
 
+	if ( ! term_exists( $slug ) )
+		return $slug;
+
 	// If the taxonomy supports hierarchy and the term has a parent, make the slug unique
 	// by incorporating parent slugs.
 	if ( is_taxonomy_hierarchical($term->taxonomy) && !empty($term->parent) ) {
@@ -1557,7 +2256,10 @@
 			$parent_term = get_term($the_parent, $term->taxonomy);
 			if ( is_wp_error($parent_term) || empty($parent_term) )
 				break;
-				$slug .= '-' . $parent_term->slug;
+			$slug .= '-' . $parent_term->slug;
+			if ( ! term_exists( $slug ) )
+				return $slug;
+
 			if ( empty($parent_term->parent) )
 				break;
 			$the_parent = $parent_term->parent;
@@ -1621,7 +2323,7 @@
 function wp_update_term( $term_id, $taxonomy, $args = array() ) {
 	global $wpdb;
 
-	if ( ! is_taxonomy($taxonomy) )
+	if ( ! taxonomy_exists($taxonomy) )
 		return new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 
 	$term_id = (int) $term_id;
@@ -1670,12 +2372,15 @@
 		}
 	}
 
+	// Check $parent to see if it will cause a hierarchy loop
+	$parent = apply_filters( 'wp_update_term_parent', $parent, $term_id, $taxonomy, compact( array_keys( $args ) ), $args );
+
 	// Check for duplicate slug
 	$id = $wpdb->get_var( $wpdb->prepare( "SELECT term_id FROM $wpdb->terms WHERE slug = %s", $slug ) );
 	if ( $id && ($id != $term_id) ) {
 		// If an empty slug was passed or the parent changed, reset the slug to something unique.
 		// Otherwise, bail.
-		if ( $empty_slug || ( $parent != $term->parent) )
+		if ( $empty_slug || ( $parent != $term['parent']) )
 			$slug = wp_unique_term_slug($slug, (object) $args);
 		else
 			return new WP_Error('duplicate_term_slug', sprintf(__('The slug &#8220;%s&#8221; is already in use by another term'), $slug));
@@ -1689,9 +2394,9 @@
 	do_action( 'edited_terms', $term_id );
 
 	$tt_id = $wpdb->get_var( $wpdb->prepare( "SELECT tt.term_taxonomy_id FROM $wpdb->term_taxonomy AS tt INNER JOIN $wpdb->terms AS t ON tt.term_id = t.term_id WHERE tt.taxonomy = %s AND t.term_id = %d", $taxonomy, $term_id) );
-	do_action( 'edit_term_taxonomy', $tt_id );
+	do_action( 'edit_term_taxonomy', $tt_id, $taxonomy );
 	$wpdb->update( $wpdb->term_taxonomy, compact( 'term_id', 'taxonomy', 'description', 'parent' ), array( 'term_taxonomy_id' => $tt_id ) );
-	do_action( 'edited_term_taxonomy', $tt_id );
+	do_action( 'edited_term_taxonomy', $tt_id, $taxonomy );
 
 	do_action("edit_term", $term_id, $tt_id, $taxonomy);
 	do_action("edit_$taxonomy", $term_id, $tt_id);
@@ -1730,7 +2435,7 @@
 /**
  * Updates the amount of terms in taxonomy.
  *
- * If there is a taxonomy callback applyed, then it will be called for updating
+ * If there is a taxonomy callback applied, then it will be called for updating
  * the count.
  *
  * The default action is to count what the amount of terms have the relationship
@@ -1787,19 +2492,24 @@
 
 	$taxonomy = get_taxonomy($taxonomy);
 	if ( !empty($taxonomy->update_count_callback) ) {
-		call_user_func($taxonomy->update_count_callback, $terms);
+		call_user_func($taxonomy->update_count_callback, $terms, $taxonomy);
 	} else {
-		// Default count updater
-		foreach ( (array) $terms as $term) {
-			$count = $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->term_relationships WHERE term_taxonomy_id = %d", $term) );
-			do_action( 'edit_term_taxonomy', $term );
-			$wpdb->update( $wpdb->term_taxonomy, compact( 'count' ), array( 'term_taxonomy_id' => $term ) );
-			do_action( 'edited_term_taxonomy', $term );
+		$object_types = (array) $taxonomy->object_type;
+		foreach ( $object_types as &$object_type ) {
+			if ( 0 === strpos( $object_type, 'attachment:' ) )
+				list( $object_type ) = explode( ':', $object_type );
 		}
 
+		if ( $object_types == array_filter( $object_types, 'post_type_exists' ) ) {
+			// Only post types are attached to this taxonomy
+			_update_post_term_count( $terms, $taxonomy );
+		} else {
+			// Default count updater
+			_update_generic_term_count( $terms, $taxonomy );
+		}
 	}
 
-	clean_term_cache($terms);
+	clean_term_cache($terms, '', false);
 
 	return true;
 }
@@ -1808,7 +2518,6 @@
 // Cache
 //
 
-
 /**
  * Removes the taxonomy relationship to terms from the cache.
  *
@@ -1838,7 +2547,6 @@
 	do_action('clean_object_term_cache', $object_ids, $object_type);
 }
 
-
 /**
  * Will remove all of the term ids from the cache.
  *
@@ -1849,8 +2557,9 @@
  *
  * @param int|array $ids Single or list of Term IDs
  * @param string $taxonomy Can be empty and will assume tt_ids, else will use for context.
+ * @param bool $clean_taxonomy Whether to clean taxonomy wide caches (true), or just individual term object caches (false). Default is true.
  */
-function clean_term_cache($ids, $taxonomy = '') {
+function clean_term_cache($ids, $taxonomy = '', $clean_taxonomy = true) {
 	global $wpdb;
 	static $cleaned = array();
 
@@ -1860,35 +2569,44 @@
 	$taxonomies = array();
 	// If no taxonomy, assume tt_ids.
 	if ( empty($taxonomy) ) {
-		$tt_ids = implode(', ', $ids);
+		$tt_ids = array_map('intval', $ids);
+		$tt_ids = implode(', ', $tt_ids);
 		$terms = $wpdb->get_results("SELECT term_id, taxonomy FROM $wpdb->term_taxonomy WHERE term_taxonomy_id IN ($tt_ids)");
+		$ids = array();
 		foreach ( (array) $terms as $term ) {
 			$taxonomies[] = $term->taxonomy;
+			$ids[] = $term->term_id;
 			wp_cache_delete($term->term_id, $term->taxonomy);
 		}
 		$taxonomies = array_unique($taxonomies);
 	} else {
-		foreach ( $ids as $id ) {
-			wp_cache_delete($id, $taxonomy);
+		$taxonomies = array($taxonomy);
+		foreach ( $taxonomies as $taxonomy ) {
+			foreach ( $ids as $id ) {
+				wp_cache_delete($id, $taxonomy);
+			}
 		}
-		$taxonomies = array($taxonomy);
 	}
 
 	foreach ( $taxonomies as $taxonomy ) {
 		if ( isset($cleaned[$taxonomy]) )
 			continue;
 		$cleaned[$taxonomy] = true;
-		wp_cache_delete('all_ids', $taxonomy);
-		wp_cache_delete('get', $taxonomy);
-		delete_option("{$taxonomy}_children");
+
+		if ( $clean_taxonomy ) {
+			wp_cache_delete('all_ids', $taxonomy);
+			wp_cache_delete('get', $taxonomy);
+			delete_option("{$taxonomy}_children");
+			// Regenerate {$taxonomy}_children
+			_get_term_hierarchy($taxonomy);
+		}
+
+		do_action('clean_term_cache', $ids, $taxonomy);
 	}
 
 	wp_cache_set('last_changed', time(), 'terms');
-
-	do_action('clean_term_cache', $ids, $taxonomy);
 }
 
-
 /**
  * Retrieves the taxonomy relationship to the term object id.
  *
@@ -1907,7 +2625,6 @@
 	return $cache;
 }
 
-
 /**
  * Updates the cache for Term ID(s).
  *
@@ -1954,14 +2671,14 @@
 	if ( empty( $ids ) )
 		return false;
 
-	$terms = wp_get_object_terms($ids, $taxonomies, 'fields=all_with_object_id');
+	$terms = wp_get_object_terms($ids, $taxonomies, array('fields' => 'all_with_object_id'));
 
 	$object_terms = array();
 	foreach ( (array) $terms as $term )
 		$object_terms[$term->object_id][$term->taxonomy][$term->term_id] = $term;
 
 	foreach ( $ids as $id ) {
-		foreach ( $taxonomies  as $taxonomy ) {
+		foreach ( $taxonomies as $taxonomy ) {
 			if ( ! isset($object_terms[$id][$taxonomy]) ) {
 				if ( !isset($object_terms[$id]) )
 					$object_terms[$id] = array();
@@ -1972,12 +2689,11 @@
 
 	foreach ( $object_terms as $id => $value ) {
 		foreach ( $value as $taxonomy => $terms ) {
-			wp_cache_set($id, $terms, "{$taxonomy}_relationships");
+			wp_cache_add( $id, $terms, "{$taxonomy}_relationships" );
 		}
 	}
 }
 
-
 /**
  * Updates Terms to Taxonomy in cache.
  *
@@ -2002,7 +2718,6 @@
 // Private
 //
 
-
 /**
  * Retrieves children of taxonomy as Term IDs.
  *
@@ -2015,27 +2730,26 @@
  *	 option. That is the name of the taxonomy, immediately followed by '_children'.
  *
  * @param string $taxonomy Taxonomy Name
- * @return array Empty if $taxonomy isn't hierarachical or returns children as Term IDs.
+ * @return array Empty if $taxonomy isn't hierarchical or returns children as Term IDs.
  */
 function _get_term_hierarchy($taxonomy) {
 	if ( !is_taxonomy_hierarchical($taxonomy) )
 		return array();
 	$children = get_option("{$taxonomy}_children");
+
 	if ( is_array($children) )
 		return $children;
-
 	$children = array();
-	$terms = get_terms($taxonomy, 'get=all');
-	foreach ( $terms as $term ) {
-		if ( $term->parent > 0 )
-			$children[$term->parent][] = $term->term_id;
+	$terms = get_terms($taxonomy, array('get' => 'all', 'orderby' => 'id', 'fields' => 'id=>parent'));
+	foreach ( $terms as $term_id => $parent ) {
+		if ( $parent > 0 )
+			$children[$parent][] = $term_id;
 	}
 	update_option("{$taxonomy}_children", $children);
 
 	return $children;
 }
 
-
 /**
  * Get the subset of $terms that are descendants of $term_id.
  *
@@ -2092,7 +2806,6 @@
 	return $term_list;
 }
 
-
 /**
  * Add count of children to parent count.
  *
@@ -2129,7 +2842,9 @@
 	}
 
 	// Get the object and term ids and stick them in a lookup table
-	$results = $wpdb->get_results("SELECT object_id, term_taxonomy_id FROM $wpdb->term_relationships INNER JOIN $wpdb->posts ON object_id = ID WHERE term_taxonomy_id IN (".join(',', array_keys($term_ids)).") AND post_type = 'post' AND post_status = 'publish'");
+	$tax_obj = get_taxonomy($taxonomy);
+	$object_types = esc_sql($tax_obj->object_type);
+	$results = $wpdb->get_results("SELECT object_id, term_taxonomy_id FROM $wpdb->term_relationships INNER JOIN $wpdb->posts ON object_id = ID WHERE term_taxonomy_id IN (" . implode(',', array_keys($term_ids)) . ") AND post_type IN ('" . implode("', '", $object_types) . "') AND post_status = 'publish'");
 	foreach ( $results as $row ) {
 		$id = $term_ids[$row->term_taxonomy_id];
 		$term_items[$id][$row->object_id] = isset($term_items[$id][$row->object_id]) ? ++$term_items[$id][$row->object_id] : 1;
@@ -2138,8 +2853,8 @@
 	// Touch every ancestor's lookup row for each post in each term
 	foreach ( $term_ids as $term_id ) {
 		$child = $term_id;
-		while ( $parent = $terms_by_id[$child]->parent ) {
-			if ( !empty($term_items[$term_id]) )
+		while ( !empty( $terms_by_id[$child] ) && $parent = $terms_by_id[$child]->parent ) {
+			if ( !empty( $term_items[$term_id] ) )
 				foreach ( $term_items[$term_id] as $item_id => $touches ) {
 					$term_items[$parent][$item_id] = isset($term_items[$parent][$item_id]) ? ++$term_items[$parent][$item_id]: 1;
 				}
@@ -2158,7 +2873,7 @@
 //
 
 /**
- * Will update term count based on posts.
+ * Will update term count based on object types of the current taxonomy.
  *
  * Private function for the default callback for post_tag and category
  * taxonomies.
@@ -2170,29 +2885,81 @@
  * @uses $wpdb
  *
  * @param array $terms List of Term taxonomy IDs
+ * @param object $taxonomy Current taxonomy object of terms
  */
-function _update_post_term_count( $terms ) {
+function _update_post_term_count( $terms, $taxonomy ) {
+	global $wpdb;
+
+	$object_types = (array) $taxonomy->object_type;
+
+	foreach ( $object_types as &$object_type )
+		list( $object_type ) = explode( ':', $object_type );
+
+	$object_types = array_unique( $object_types );
+
+	if ( false !== ( $check_attachments = array_search( 'attachment', $object_types ) ) ) {
+		unset( $object_types[ $check_attachments ] );
+		$check_attachments = true;
+	}
+
+	if ( $object_types )
+		$object_types = esc_sql( array_filter( $object_types, 'post_type_exists' ) );
+
+	foreach ( (array) $terms as $term ) {
+		$count = 0;
+
+		// Attachments can be 'inherit' status, we need to base count off the parent's status if so
+		if ( $check_attachments )
+			$count += (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->term_relationships, $wpdb->posts p1 WHERE p1.ID = $wpdb->term_relationships.object_id AND ( post_status = 'publish' OR ( post_status = 'inherit' AND post_parent > 0 AND ( SELECT post_status FROM $wpdb->posts WHERE ID = p1.post_parent ) = 'publish' ) ) AND post_type = 'attachment' AND term_taxonomy_id = %d", $term ) );
+
+		if ( $object_types )
+			$count += (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->term_relationships, $wpdb->posts WHERE $wpdb->posts.ID = $wpdb->term_relationships.object_id AND post_status = 'publish' AND post_type IN ('" . implode("', '", $object_types ) . "') AND term_taxonomy_id = %d", $term ) );
+
+		do_action( 'edit_term_taxonomy', $term, $taxonomy );
+		$wpdb->update( $wpdb->term_taxonomy, compact( 'count' ), array( 'term_taxonomy_id' => $term ) );
+		do_action( 'edited_term_taxonomy', $term, $taxonomy );
+	}
+}
+
+/**
+ * Will update term count based on number of objects.
+ *
+ * Default callback for the link_category taxonomy.
+ *
+ * @package WordPress
+ * @subpackage Taxonomy
+ * @since 3.3.0
+ * @uses $wpdb
+ *
+ * @param array $terms List of Term taxonomy IDs
+ * @param object $taxonomy Current taxonomy object of terms
+ */
+function _update_generic_term_count( $terms, $taxonomy ) {
 	global $wpdb;
 
 	foreach ( (array) $terms as $term ) {
-		$count = $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->term_relationships, $wpdb->posts WHERE $wpdb->posts.ID = $wpdb->term_relationships.object_id AND post_status = 'publish' AND post_type = 'post' AND term_taxonomy_id = %d", $term ) );
-		do_action( 'edit_term_taxonomy', $term );
+		$count = $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->term_relationships WHERE term_taxonomy_id = %d", $term ) );
+
+		do_action( 'edit_term_taxonomy', $term, $taxonomy );
 		$wpdb->update( $wpdb->term_taxonomy, compact( 'count' ), array( 'term_taxonomy_id' => $term ) );
-		do_action( 'edited_term_taxonomy', $term );
+		do_action( 'edited_term_taxonomy', $term, $taxonomy );
 	}
 }
 
-
 /**
  * Generates a permalink for a taxonomy term archive.
  *
  * @since 2.5.0
  *
+ * @uses apply_filters() Calls 'term_link' with term link and term object, and taxonomy parameters.
+ * @uses apply_filters() For the post_tag Taxonomy, Calls 'tag_link' with tag link and tag ID as parameters.
+ * @uses apply_filters() For the category Taxonomy, Calls 'category_link' filter on category link and category ID.
+ *
  * @param object|int|string $term
- * @param string $taxonomy
- * @return string HTML link to taxonomy term archive
+ * @param string $taxonomy (optional if $term is object)
+ * @return string|WP_Error HTML link to taxonomy term archive on success, WP_Error if term does not exist.
  */
-function get_term_link( $term, $taxonomy ) {
+function get_term_link( $term, $taxonomy = '') {
 	global $wp_rewrite;
 
 	if ( !is_object($term) ) {
@@ -2202,30 +2969,50 @@
 			$term = &get_term_by('slug', $term, $taxonomy);
 		}
 	}
+
+	if ( !is_object($term) )
+		$term = new WP_Error('invalid_term', __('Empty Term'));
+
 	if ( is_wp_error( $term ) )
 		return $term;
 
-	// use legacy functions for core taxonomies until they are fully plugged in
-	if ( $taxonomy == 'category' )
-		return get_category_link((int) $term->term_id);
-	if ( $taxonomy == 'post_tag' )
-		return get_tag_link((int) $term->term_id);
+	$taxonomy = $term->taxonomy;
 
 	$termlink = $wp_rewrite->get_extra_permastruct($taxonomy);
 
 	$slug = $term->slug;
+	$t = get_taxonomy($taxonomy);
 
 	if ( empty($termlink) ) {
-		$file = trailingslashit( get_option('home') );
-		$t = get_taxonomy($taxonomy);
-		if ( $t->query_var )
-			$termlink = "$file?$t->query_var=$slug";
+		if ( 'category' == $taxonomy )
+			$termlink = '?cat=' . $term->term_id;
+		elseif ( $t->query_var )
+			$termlink = "?$t->query_var=$slug";
 		else
-			$termlink = "$file?taxonomy=$taxonomy&term=$slug";
+			$termlink = "?taxonomy=$taxonomy&term=$slug";
+		$termlink = home_url($termlink);
 	} else {
-		$termlink = str_replace("%$taxonomy%", $slug, $termlink);
-		$termlink = get_option('home') . user_trailingslashit($termlink, 'category');
+		if ( $t->rewrite['hierarchical'] ) {
+			$hierarchical_slugs = array();
+			$ancestors = get_ancestors($term->term_id, $taxonomy);
+			foreach ( (array)$ancestors as $ancestor ) {
+				$ancestor_term = get_term($ancestor, $taxonomy);
+				$hierarchical_slugs[] = $ancestor_term->slug;
+			}
+			$hierarchical_slugs = array_reverse($hierarchical_slugs);
+			$hierarchical_slugs[] = $slug;
+			$termlink = str_replace("%$taxonomy%", implode('/', $hierarchical_slugs), $termlink);
+		} else {
+			$termlink = str_replace("%$taxonomy%", $slug, $termlink);
+		}
+		$termlink = home_url( user_trailingslashit($termlink, 'category') );
 	}
+	// Back Compat filters.
+	if ( 'post_tag' == $taxonomy )
+		$termlink = apply_filters( 'tag_link', $termlink, $term->term_id );
+	elseif ( 'category' == $taxonomy )
+		$termlink = apply_filters( 'category_link', $termlink, $term->term_id );
+
 	return apply_filters('term_link', $termlink, $term, $taxonomy);
 }
 
@@ -2241,6 +3028,7 @@
  * 'before' : default is empty string. Display before taxonomies list.
  * 'sep' : default is empty string. Separate every taxonomy with value in this.
  * 'after' : default is empty string. Display this after the taxonomies list.
+ * 'template' : The template to use for displaying the taxonomy terms.
  *
  * @since 2.5.0
  * @uses get_the_taxonomies()
@@ -2253,12 +3041,13 @@
 		'before' => '',
 		'sep' => ' ',
 		'after' => '',
+		'template' => '%s: %l.'
 	);
 
 	$r = wp_parse_args( $args, $defaults );
 	extract( $r, EXTR_SKIP );
 
-	echo $before . join($sep, get_the_taxonomies($post)) . $after;
+	echo $before . join($sep, get_the_taxonomies($post, $r)) . $after;
 }
 
 /**
@@ -2270,21 +3059,25 @@
  * @since 2.5.0
  *
  * @param int $post Optional. Post ID or will use Global Post ID (in loop).
+ * @param array $args Override the defaults.
  * @return array
  */
-function get_the_taxonomies($post = 0) {
+function get_the_taxonomies($post = 0, $args = array() ) {
 	if ( is_int($post) )
 		$post =& get_post($post);
 	elseif ( !is_object($post) )
 		$post =& $GLOBALS['post'];
 
+	$args = wp_parse_args( $args, array(
+		'template' => '%s: %l.',
+	) );
+	extract( $args, EXTR_SKIP );
+
 	$taxonomies = array();
 
 	if ( !$post )
 		return $taxonomies;
 
-	$template = apply_filters('taxonomy_template', '%s: %l.');
-
 	foreach ( get_object_taxonomies($post) as $taxonomy ) {
 		$t = (array) get_taxonomy($taxonomy);
 		if ( empty($t['label']) )
@@ -2301,7 +3094,7 @@
 		$links = array();
 
 		foreach ( $terms as $term )
-			$links[] = "<a href='" . esc_attr(get_term_link($term, $taxonomy)) . "'>$term->name</a>";
+			$links[] = "<a href='" . esc_attr( get_term_link($term) ) . "'>$term->name</a>";
 
 		if ( $links )
 			$taxonomies[$taxonomy] = wp_sprintf($t['template'], $t['label'], $links, $terms);
@@ -2335,9 +3128,9 @@
  * @uses get_object_term_cache()
  * @uses wp_get_object_terms()
  *
- * @param int $object_id.  ID of the object (post ID, link ID, ...)
- * @param string $taxonomy.  Single taxonomy name
- * @param int|string|array $terms Optional.  Term term_id, name, slug or array of said
+ * @param int $object_id ID of the object (post ID, link ID, ...)
+ * @param string $taxonomy Single taxonomy name
+ * @param int|string|array $terms Optional. Term term_id, name, slug or array of said
  * @return bool|WP_Error. WP_Error on input error.
  */
 function is_object_in_term( $object_id, $taxonomy, $terms = null ) {
@@ -2374,4 +3167,118 @@
 	return false;
 }
 
-?>
+/**
+ * Determine if the given object type is associated with the given taxonomy.
+ *
+ * @since 3.0.0
+ * @uses get_object_taxonomies()
+ *
+ * @param string $object_type Object type string
+ * @param string $taxonomy Single taxonomy name
+ * @return bool True if object is associated with the taxonomy, otherwise false.
+ */
+function is_object_in_taxonomy($object_type, $taxonomy) {
+	$taxonomies = get_object_taxonomies($object_type);
+
+	if ( empty($taxonomies) )
+		return false;
+
+	if ( in_array($taxonomy, $taxonomies) )
+		return true;
+
+	return false;
+}
+
+/**
+ * Get an array of ancestor IDs for a given object.
+ *
+ * @param int $object_id The ID of the object
+ * @param string $object_type The type of object for which we'll be retrieving ancestors.
+ * @return array of ancestors from lowest to highest in the hierarchy.
+ */
+function get_ancestors($object_id = 0, $object_type = '') {
+	$object_id = (int) $object_id;
+
+	$ancestors = array();
+
+	if ( empty( $object_id ) ) {
+		return apply_filters('get_ancestors', $ancestors, $object_id, $object_type);
+	}
+
+	if ( is_taxonomy_hierarchical( $object_type ) ) {
+		$term = get_term($object_id, $object_type);
+		while ( ! is_wp_error($term) && ! empty( $term->parent ) && ! in_array( $term->parent, $ancestors ) ) {
+			$ancestors[] = (int) $term->parent;
+			$term = get_term($term->parent, $object_type);
+		}
+	} elseif ( null !== get_post_type_object( $object_type ) ) {
+		$object = get_post($object_id);
+		if ( ! is_wp_error( $object ) && isset( $object->ancestors ) && is_array( $object->ancestors ) )
+			$ancestors = $object->ancestors;
+		else {
+			while ( ! is_wp_error($object) && ! empty( $object->post_parent ) && ! in_array( $object->post_parent, $ancestors ) ) {
+				$ancestors[] = (int) $object->post_parent;
+				$object = get_post($object->post_parent);
+			}
+		}
+	}
+
+	return apply_filters('get_ancestors', $ancestors, $object_id, $object_type);
+}
+
+/**
+ * Returns the term's parent's term_ID
+ *
+ * @since 3.1.0
+ *
+ * @param int $term_id
+ * @param string $taxonomy
+ *
+ * @return int|bool false on error
+ */
+function wp_get_term_taxonomy_parent_id( $term_id, $taxonomy ) {
+	$term = get_term( $term_id, $taxonomy );
+	if ( !$term || is_wp_error( $term ) )
+		return false;
+	return (int) $term->parent;
+}
+
+/**
+ * Checks the given subset of the term hierarchy for hierarchy loops.
+ * Prevents loops from forming and breaks those that it finds.
+ *
+ * Attached to the wp_update_term_parent filter.
+ *
+ * @since 3.1.0
+ * @uses wp_find_hierarchy_loop()
+ *
+ * @param int $parent term_id of the parent for the term we're checking.
+ * @param int $term_id The term we're checking.
+ * @param string $taxonomy The taxonomy of the term we're checking.
+ *
+ * @return int The new parent for the term.
+ */
+function wp_check_term_hierarchy_for_loops( $parent, $term_id, $taxonomy ) {
+	// Nothing fancy here - bail
+	if ( !$parent )
+		return 0;
+
+	// Can't be its own parent
+	if ( $parent == $term_id )
+		return 0;
+
+	// Now look for larger loops
+
+	if ( !$loop = wp_find_hierarchy_loop( 'wp_get_term_taxonomy_parent_id', $term_id, $parent, array( $taxonomy ) ) )
+		return $parent; // No loop
+
+	// Setting $parent to the given value causes a loop
+	if ( isset( $loop[$term_id] ) )
+		return 0;
+
+	// There's a loop, but it doesn't contain $term_id. Break the loop.
+	foreach ( array_keys( $loop ) as $loop_member )
+		wp_update_term( $loop_member, $taxonomy, array( 'parent' => 0 ) );
+
+	return $parent;
+}