<?php

/**

 * Meta API

 *

 * Functions for retrieving and manipulating metadata

 *

 * @package WordPress

 * @subpackage Meta

 * @since 2.9.0

 */

function add_metadata($meta_type, $object_id, $meta_key, $meta_value, $unique = false) {

	if ( !$meta_type || !$meta_key )

		return false;

	if ( ! $table = _get_meta_table($meta_type) )

		return false;

	global $wpdb;

	$column = esc_sql($meta_type . '_id');

	// expected_slashed ($meta_key)

	$meta_key = stripslashes($meta_key);

	if ( $unique && $wpdb->get_var( $wpdb->prepare(

		"SELECT COUNT(*) FROM $table WHERE meta_key = %s AND $column = %d",

		$meta_key, $object_id ) ) )

		return false;

	$meta_value = maybe_serialize( stripslashes_deep($meta_value) );

	$wpdb->insert( $table, array(

		$column => $object_id,

		'meta_key' => $meta_key,

		'meta_value' => $meta_value

	) );

	wp_cache_delete($object_id, $meta_type . '_meta');

	do_action( "added_{$meta_type}_meta", $wpdb->insert_id, $object_id, $meta_key, $meta_value );

	return true;

}

function update_metadata($meta_type, $object_id, $meta_key, $meta_value, $prev_value = '') {

	if ( !$meta_type || !$meta_key )

		return false;

	if ( ! $table = _get_meta_table($meta_type) )

		return false;

	global $wpdb;

	$column = esc_sql($meta_type . '_id');

	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';

	// expected_slashed ($meta_key)

	$meta_key = stripslashes($meta_key);

	if ( ! $meta_id = $wpdb->get_var( $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s AND $column = %d", $meta_key, $object_id ) ) )

		return add_metadata($meta_type, $object_id, $meta_key, $meta_value);

	$meta_value = maybe_serialize( stripslashes_deep($meta_value) );

	$data  = compact( 'meta_value' );

	$where = array( $column => $object_id, 'meta_key' => $meta_key );

	if ( !empty( $prev_value ) ) {

		$prev_value = maybe_serialize($prev_value);

		$where['meta_value'] = $prev_value;

	}

	do_action( "update_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $meta_value );

	$wpdb->update( $table, $data, $where );

	wp_cache_delete($object_id, $meta_type . '_meta');

	do_action( "updated_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $meta_value );

	return true;

}

function delete_metadata($meta_type, $object_id, $meta_key, $meta_value = '', $delete_all = false) {

	if ( !$meta_type || !$meta_key || (!$delete_all && ! (int)$object_id) )

		return false;

	if ( ! $table = _get_meta_table($meta_type) )

		return false;

	global $wpdb;

	$type_column = esc_sql($meta_type . '_id');

	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';

	// expected_slashed ($meta_key)

	$meta_key = stripslashes($meta_key);

	$meta_value = maybe_serialize( stripslashes_deep($meta_value) );

	$query = $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s", $meta_key );

	if ( !$delete_all )

		$query .= $wpdb->prepare(" AND $type_column = %d", $object_id );

	if ( $meta_value )

		$query .= $wpdb->prepare(" AND meta_value = %s", $meta_value );

	$meta_ids = $wpdb->get_col( $query );

	if ( !count( $meta_ids ) )

		return false;

	$query = "DELETE FROM $table WHERE $id_column IN( " . implode( ',', $meta_ids ) . " )";

	$count = $wpdb->query($query);

	if ( !$count )

		return false;

	wp_cache_delete($object_id, $meta_type . '_meta');

	do_action( "deleted_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $meta_value );

	return true;

}

function get_metadata($meta_type, $object_id, $meta_key = '', $single = false) {

	if ( !$meta_type )

		return false;

	$meta_cache = wp_cache_get($object_id, $meta_type . '_meta');

	if ( !$meta_cache ) {

		update_meta_cache($meta_type, $object_id);

		$meta_cache = wp_cache_get($object_id, $meta_type . '_meta');

	}

	if ( ! $meta_key )

		return $meta_cache;

	if ( isset($meta_cache[$meta_key]) ) {

		if ( $single ) {

			return maybe_unserialize( $meta_cache[$meta_key][0] );

		} else {

			return array_map('maybe_unserialize', $meta_cache[$meta_key]);

		}

	}

	if ($single)

		return '';

	else

		return array();

}

function update_meta_cache($meta_type, $object_ids) {

	if ( empty( $meta_type ) || empty( $object_ids ) )

		return false;

	if ( ! $table = _get_meta_table($meta_type) )

		return false;

	$column = esc_sql($meta_type . '_id');

	global $wpdb;

	if ( !is_array($object_ids) ) {

		$object_ids = preg_replace('|[^0-9,]|', '', $object_ids);

		$object_ids = explode(',', $object_ids);

	}

	$object_ids = array_map('intval', $object_ids);

	$cache_key = $meta_type . '_meta';

	$ids = array();

	foreach ( $object_ids as $id ) {

		if ( false === wp_cache_get($id, $cache_key) )

			$ids[] = $id;

	}

	if ( empty( $ids ) )

		return false;

	// Get meta info

	$id_list = join(',', $ids);

	$cache = array();

	$meta_list = $wpdb->get_results( $wpdb->prepare("SELECT $column, meta_key, meta_value FROM $table WHERE $column IN ($id_list)",

		$meta_type), ARRAY_A );

	if ( !empty($meta_list) ) {

		foreach ( $meta_list as $metarow) {

			$mpid = intval($metarow[$column]);

			$mkey = $metarow['meta_key'];

			$mval = $metarow['meta_value'];

			// Force subkeys to be array type:

			if ( !isset($cache[$mpid]) || !is_array($cache[$mpid]) )

				$cache[$mpid] = array();

			if ( !isset($cache[$mpid][$mkey]) || !is_array($cache[$mpid][$mkey]) )

				$cache[$mpid][$mkey] = array();

			// Add a value to the current pid/key:

			$cache[$mpid][$mkey][] = $mval;

		}

	}

	foreach ( $ids as $id ) {

		if ( ! isset($cache[$id]) )

			$cache[$id] = array();

	}

	foreach ( array_keys($cache) as $object)

		wp_cache_set($object, $cache[$object], $cache_key);

	return $cache;

}

function _get_meta_table($type) {

	global $wpdb;

	$table_name = $type . 'meta';

	if ( empty($wpdb->$table_name) )

		return false;

	return $wpdb->$table_name;

}

?>