+ * Splits a batch of shared taxonomy terms.
+ *
+ * @since 4.3.0
+ *
+ * @global wpdb $wpdb WordPress database abstraction object.
+ */
+function _wp_batch_split_terms() {
+ global $wpdb;
+
+ $lock_name = 'term_split.lock';
+
+ // Try to lock.
+ $lock_result = $wpdb->query( $wpdb->prepare( "INSERT IGNORE INTO `$wpdb->options` ( `option_name`, `option_value`, `autoload` ) VALUES (%s, %s, 'no') /* LOCK */", $lock_name, time() ) );
+
+ if ( ! $lock_result ) {
+ $lock_result = get_option( $lock_name );
+
+ // Bail if we were unable to create a lock, or if the existing lock is still valid.
+ if ( ! $lock_result || ( $lock_result > ( time() - HOUR_IN_SECONDS ) ) ) {
+ wp_schedule_single_event( time() + ( 5 * MINUTE_IN_SECONDS ), 'wp_split_shared_term_batch' );
+ return;
+ }
+ }
+
+ // Update the lock, as by this point we've definitely got a lock, just need to fire the actions.
+ update_option( $lock_name, time() );
+
+ // Get a list of shared terms (those with more than one associated row in term_taxonomy).
+ $shared_terms = $wpdb->get_results(
+ "SELECT tt.term_id, t.*, count(*) as term_tt_count FROM {$wpdb->term_taxonomy} tt
+ LEFT JOIN {$wpdb->terms} t ON t.term_id = tt.term_id
+ GROUP BY t.term_id
+ HAVING term_tt_count > 1
+ LIMIT 10"
+ );
+
+ // No more terms, we're done here.
+ if ( ! $shared_terms ) {
+ update_option( 'finished_splitting_shared_terms', true );
+ delete_option( $lock_name );
+ return;
+ }
+
+ // Shared terms found? We'll need to run this script again.
+ wp_schedule_single_event( time() + ( 2 * MINUTE_IN_SECONDS ), 'wp_split_shared_term_batch' );
+
+ // Rekey shared term array for faster lookups.
+ $_shared_terms = array();
+ foreach ( $shared_terms as $shared_term ) {
+ $term_id = intval( $shared_term->term_id );
+ $_shared_terms[ $term_id ] = $shared_term;
+ }
+ $shared_terms = $_shared_terms;
+
+ // Get term taxonomy data for all shared terms.
+ $shared_term_ids = implode( ',', array_keys( $shared_terms ) );
+ $shared_tts = $wpdb->get_results( "SELECT * FROM {$wpdb->term_taxonomy} WHERE `term_id` IN ({$shared_term_ids})" );
+
+ // Split term data recording is slow, so we do it just once, outside the loop.
+ $split_term_data = get_option( '_split_terms', array() );
+ $skipped_first_term = $taxonomies = array();
+ foreach ( $shared_tts as $shared_tt ) {
+ $term_id = intval( $shared_tt->term_id );
+
+ // Don't split the first tt belonging to a given term_id.
+ if ( ! isset( $skipped_first_term[ $term_id ] ) ) {
+ $skipped_first_term[ $term_id ] = 1;
+ continue;
+ }
+
+ if ( ! isset( $split_term_data[ $term_id ] ) ) {
+ $split_term_data[ $term_id ] = array();
+ }
+
+ // Keep track of taxonomies whose hierarchies need flushing.
+ if ( ! isset( $taxonomies[ $shared_tt->taxonomy ] ) ) {
+ $taxonomies[ $shared_tt->taxonomy ] = 1;
+ }
+
+ // Split the term.
+ $split_term_data[ $term_id ][ $shared_tt->taxonomy ] = _split_shared_term( $shared_terms[ $term_id ], $shared_tt, false );
+ }
+
+ // Rebuild the cached hierarchy for each affected taxonomy.
+ foreach ( array_keys( $taxonomies ) as $tax ) {
+ delete_option( "{$tax}_children" );
+ _get_term_hierarchy( $tax );
+ }
+
+ update_option( '_split_terms', $split_term_data );
+
+ delete_option( $lock_name );
+}
+
+/**
+ * In order to avoid the _wp_batch_split_terms() job being accidentally removed,
+ * check that it's still scheduled while we haven't finished splitting terms.
+ *
+ * @ignore
+ * @since 4.3.0
+ */
+function _wp_check_for_scheduled_split_terms() {
+ if ( ! get_option( 'finished_splitting_shared_terms' ) && ! wp_next_scheduled( 'wp_split_shared_term_batch' ) ) {
+ wp_schedule_single_event( time() + MINUTE_IN_SECONDS, 'wp_split_shared_term_batch' );
+ }
+}
+
+/**
+ * Check default categories when a term gets split to see if any of them need to be updated.
+ *
+ * @ignore
+ * @since 4.2.0
+ *
+ * @param int $term_id ID of the formerly shared term.
+ * @param int $new_term_id ID of the new term created for the $term_taxonomy_id.
+ * @param int $term_taxonomy_id ID for the term_taxonomy row affected by the split.
+ * @param string $taxonomy Taxonomy for the split term.
+ */
+function _wp_check_split_default_terms( $term_id, $new_term_id, $term_taxonomy_id, $taxonomy ) {
+ if ( 'category' != $taxonomy ) {
+ return;
+ }
+
+ foreach ( array( 'default_category', 'default_link_category', 'default_email_category' ) as $option ) {
+ if ( $term_id == get_option( $option, -1 ) ) {
+ update_option( $option, $new_term_id );
+ }
+ }
+}
+
+/**
+ * Check menu items when a term gets split to see if any of them need to be updated.
+ *
+ * @ignore
+ * @since 4.2.0
+ *
+ * @global wpdb $wpdb
+ *
+ * @param int $term_id ID of the formerly shared term.
+ * @param int $new_term_id ID of the new term created for the $term_taxonomy_id.
+ * @param int $term_taxonomy_id ID for the term_taxonomy row affected by the split.
+ * @param string $taxonomy Taxonomy for the split term.
+ */
+function _wp_check_split_terms_in_menus( $term_id, $new_term_id, $term_taxonomy_id, $taxonomy ) {
+ global $wpdb;
+ $post_ids = $wpdb->get_col( $wpdb->prepare(
+ "SELECT m1.post_id
+ FROM {$wpdb->postmeta} AS m1
+ INNER JOIN {$wpdb->postmeta} AS m2 ON ( m2.post_id = m1.post_id )
+ INNER JOIN {$wpdb->postmeta} AS m3 ON ( m3.post_id = m1.post_id )
+ WHERE ( m1.meta_key = '_menu_item_type' AND m1.meta_value = 'taxonomy' )
+ AND ( m2.meta_key = '_menu_item_object' AND m2.meta_value = '%s' )
+ AND ( m3.meta_key = '_menu_item_object_id' AND m3.meta_value = %d )",
+ $taxonomy,
+ $term_id
+ ) );
+
+ if ( $post_ids ) {
+ foreach ( $post_ids as $post_id ) {
+ update_post_meta( $post_id, '_menu_item_object_id', $new_term_id, $term_id );
+ }
+ }
+}
+
+/**
+ * If the term being split is a nav_menu, change associations.
+ *
+ * @ignore
+ * @since 4.3.0
+ *
+ * @global wpdb $wpdb
+ *
+ * @param int $term_id ID of the formerly shared term.
+ * @param int $new_term_id ID of the new term created for the $term_taxonomy_id.
+ * @param int $term_taxonomy_id ID for the term_taxonomy row affected by the split.
+ * @param string $taxonomy Taxonomy for the split term.
+ */
+function _wp_check_split_nav_menu_terms( $term_id, $new_term_id, $term_taxonomy_id, $taxonomy ) {
+ if ( 'nav_menu' !== $taxonomy ) {
+ return;
+ }
+
+ // Update menu locations.
+ $locations = get_nav_menu_locations();
+ foreach ( $locations as $location => $menu_id ) {
+ if ( $term_id == $menu_id ) {
+ $locations[ $location ] = $new_term_id;
+ }
+ }
+ set_theme_mod( 'nav_menu_locations', $locations );
+}
+
+/**
+ * Get data about terms that previously shared a single term_id, but have since been split.
+ *
+ * @since 4.2.0
+ *
+ * @param int $old_term_id Term ID. This is the old, pre-split term ID.
+ * @return array Array of new term IDs, keyed by taxonomy.
+ */
+function wp_get_split_terms( $old_term_id ) {
+ $split_terms = get_option( '_split_terms', array() );
+
+ $terms = array();
+ if ( isset( $split_terms[ $old_term_id ] ) ) {
+ $terms = $split_terms[ $old_term_id ];
+ }
+
+ return $terms;
+}
+
+/**
+ * Get the new term ID corresponding to a previously split term.
+ *
+ * @since 4.2.0
+ *
+ * @param int $old_term_id Term ID. This is the old, pre-split term ID.
+ * @param string $taxonomy Taxonomy that the term belongs to.
+ * @return int|false If a previously split term is found corresponding to the old term_id and taxonomy,
+ * the new term_id will be returned. If no previously split term is found matching
+ * the parameters, returns false.
+ */
+function wp_get_split_term( $old_term_id, $taxonomy ) {
+ $split_terms = wp_get_split_terms( $old_term_id );
+
+ $term_id = false;
+ if ( isset( $split_terms[ $taxonomy ] ) ) {
+ $term_id = (int) $split_terms[ $taxonomy ];
+ }
+
+ return $term_id;
+}
+
+/**
+ * Generate a permalink for a taxonomy term archive.