Standardized gobs of files.

git-svn-id: http://code.elgg.org/elgg/trunk@3548 36083f99-b078-4883-b0ff-0f9b5a30f544

1 files changed, 885 insertions, 822 deletions

diff --git a/engine/lib/metadata.php b/engine/lib/metadata.php
index c6e5db4cd..5ca39b586 100644
--- a/engine/lib/metadata.php
+++ b/engine/lib/metadata.php
@@ -1,912 +1,975 @@
 <?php
-	/**
-	 * Elgg metadata
-	 * Functions to manage object metadata.
-	 * 
-	 * @package Elgg
-	 * @subpackage Core
-
-	 * @author Curverider Ltd <info@elgg.com>
-
-	 * @link http://elgg.org/
-	 */
+/**
+ * Elgg metadata
+ * Functions to manage object metadata.
+ *
+ * @package Elgg
+ * @subpackage Core
+ * @author Curverider Ltd <info@elgg.com>
+ * @link http://elgg.org/
+ */
 
+/**
+ * ElggMetadata
+ * This class describes metadata that can be attached to ElggEntities.
+ *
+ * @author Curverider Ltd <info@elgg.com>
+ * @package Elgg
+ * @subpackage Core
+ */
+class ElggMetadata extends ElggExtender {
 	/**
-	 * ElggMetadata
-	 * This class describes metadata that can be attached to ElggEntities.
-	 * 
-	 * @author Curverider Ltd <info@elgg.com>
-	 * @package Elgg
-	 * @subpackage Core
+	 * Construct a new site object, optionally from a given id value or row.
+	 *
+	 * @param mixed $id
 	 */
-	class ElggMetadata extends ElggExtender
-	{
-			
-		/**
-		 * Construct a new site object, optionally from a given id value or row.
-		 *
-		 * @param mixed $id
-		 */
-		function __construct($id = null) 
-		{
-			$this->attributes = array();
-			
-			if (!empty($id)) {
-				
-				if ($id instanceof stdClass)
-					$metadata = $id; // Create from db row
-				else
-					$metadata = get_metadata($id);	
-				
-				if ($metadata) {
-					$objarray = (array) $metadata;
-					foreach($objarray as $key => $value) {
-						$this->attributes[$key] = $value;
-					}
-					$this->attributes['type'] = "metadata";
-				}
-			}
-		}
-		
-		/**
-		 * Class member get overloading
-		 *
-		 * @param string $name
-		 * @return mixed
-		 */
-		function __get($name) {
-			return $this->get($name);
-		}
-		
-		/**
-		 * Class member set overloading
-		 *
-		 * @param string $name
-		 * @param mixed $value
-		 * @return mixed
-		 */
-		function __set($name, $value) {
-			return $this->set($name, $value);
-		}
+	function __construct($id = null) {
+		$this->attributes = array();
 
-		/**
-		 * Determines whether or not the user can edit this piece of metadata
-		 *
-		 * @return true|false Depending on permissions
-		 */
-		function canEdit() {
-			
-			if ($entity = get_entity($this->get('entity_guid'))) {
-				return $entity->canEditMetadata($this);
+		if (!empty($id)) {
+			// Create from db row
+			if ($id instanceof stdClass) {
+				$metadata = $id;
+			} else {
+				$metadata = get_metadata($id);
 			}
-			return false;
-			
-		}
-		
-		/**
-		 * Save matadata object
-		 *
-		 * @return int the metadata object id
-		 */
-		function save()
-		{
-			if ($this->id > 0)
-				return update_metadata($this->id, $this->name, $this->value, $this->value_type, $this->owner_guid, $this->access_id);
-			else
-			{ 
-				$this->id = create_metadata($this->entity_guid, $this->name, $this->value, $this->value_type, $this->owner_guid, $this->access_id);
-				if (!$this->id) throw new IOException(sprintf(elgg_new('IOException:UnableToSaveNew'), get_class()));
-				return $this->id;
+
+			if ($metadata) {
+				$objarray = (array) $metadata;
+				foreach($objarray as $key => $value) {
+					$this->attributes[$key] = $value;
+				}
+				$this->attributes['type'] = "metadata";
 			}
-			
 		}
-		
-		/**
-		 * Delete a given metadata.
-		 */
-		function delete() 
-		{ 
-			return delete_metadata($this->id); 
-		}
-		
-		/**
-		 * Get a url for this item of metadata.
-		 *
-		 * @return string
-		 */
-		public function getURL() { return get_metadata_url($this->id); }
-	
-		// SYSTEM LOG INTERFACE ////////////////////////////////////////////////////////////
-
-		/**
-		 * For a given ID, return the object associated with it.
-		 * This is used by the river functionality primarily.
-		 * This is useful for checking access permissions etc on objects.
-		 */
-		public function getObjectFromID($id) { return get_metadata($id); }
 	}
 
 	/**
-	 * Convert a database row to a new ElggMetadata
+	 * Class member get overloading
 	 *
-	 * @param stdClass $row
-	 * @return stdClass or ElggMetadata
+	 * @param string $name
+	 * @return mixed
 	 */
-	function row_to_elggmetadata($row) 
-	{
-		if (!($row instanceof stdClass))
-			return $row;
-			
-		return new ElggMetadata($row);
+	function __get($name) {
+		return $this->get($name);
 	}
 
-			
 	/**
-	 * Get a specific item of metadata.
-	 * 
-	 * @param $id int The item of metadata being retrieved.
+	 * Class member set overloading
+	 *
+	 * @param string $name
+	 * @param mixed $value
+	 * @return mixed
 	 */
-	function get_metadata($id)
-	{
-		global $CONFIG;
-
-		$id = (int)$id;
-		$access = get_access_sql_suffix("e");
-		$md_access = get_access_sql_suffix("m");
-
-		return row_to_elggmetadata(get_data_row("SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}metadata m JOIN {$CONFIG->dbprefix}entities e on e.guid = m.entity_guid JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id where m.id=$id and $access and $md_access"));
+	function __set($name, $value) {
+		return $this->set($name, $value);
 	}
-	
+
 	/**
-	 * Removes metadata on an entity with a particular name, optionally with a given value.
+	 * Determines whether or not the user can edit this piece of metadata
 	 *
-	 * @param int $entity_guid The entity GUID
-	 * @param string $name The name of the metadata
-	 * @param string $value The optional value of the item (useful for removing a single item in a multiple set)
-	 * @return true|false Depending on success
+	 * @return true|false Depending on permissions
 	 */
-	function remove_metadata($entity_guid, $name, $value = "") {
-		
-		global $CONFIG;
-		$entity_guid = (int) $entity_guid;
-		$name = sanitise_string($name);
-		$value = sanitise_string($value);
-
-		$query = "SELECT * from {$CONFIG->dbprefix}metadata WHERE entity_guid = $entity_guid and name_id=" . add_metastring($name);
-		if ($value!="")
-			$query .= " and value_id=" . add_metastring($value);
-		
-		if ($existing = get_data($query)) {
-			foreach($existing as $ex)
-				delete_metadata($ex->id);
-			return true;
+	function canEdit() {
+		if ($entity = get_entity($this->get('entity_guid'))) {
+			return $entity->canEditMetadata($this);
 		}
 		return false;
-		
 	}
-	
+
 	/**
-	 * Create a new metadata object, or update an existing one.
+	 * Save matadata object
 	 *
-	 * @param int $entity_guid
-	 * @param string $name
-	 * @param string $value
-	 * @param string $value_type
-	 * @param int $owner_guid
-	 * @param int $access_id
-	 * @param bool $allow_multiple
+	 * @return int the metadata object id
 	 */
-	function create_metadata($entity_guid, $name, $value, $value_type, $owner_guid, $access_id = ACCESS_PRIVATE, $allow_multiple = false)
-	{
-		global $CONFIG;
-
-		$entity_guid = (int)$entity_guid;
-		//$name = sanitise_string(trim($name));
-		//$value = sanitise_string(trim($value));
-		$value_type = detect_extender_valuetype($value, sanitise_string(trim($value_type)));
-		$time = time();		
-		$owner_guid = (int)$owner_guid;
-		$allow_multiple = (boolean)$allow_multiple;
-		
-		if ($owner_guid==0) $owner_guid = get_loggedin_userid();
-		
-		$access_id = (int)$access_id;
-
-		$id = false;
-	
-		$existing = get_data_row("SELECT * from {$CONFIG->dbprefix}metadata WHERE entity_guid = $entity_guid and name_id=" . add_metastring($name) . " limit 1");
-		if (($existing) && (!$allow_multiple) && (isset($value))) 
-		{ 
-			$id = $existing->id;
-			$result = update_metadata($id, $name, $value, $value_type, $owner_guid, $access_id);
-			
-			if (!$result) return false;
-		}
-		else if (isset($value))
-		{
-			// Support boolean types
-			if (is_bool($value)) {
-				if ($value)
-					$value = 1;
-				else
-					$value = 0;
-			}
-			
-			// Add the metastrings
-			$value = add_metastring($value);
-			if (!$value) return false;
-			
-			$name = add_metastring($name);
-			if (!$name) return false;
-			
-			// If ok then add it
-			$id = insert_data("INSERT into {$CONFIG->dbprefix}metadata (entity_guid, name_id, value_id, value_type, owner_guid, time_created, access_id) VALUES ($entity_guid, '$name','$value','$value_type', $owner_guid, $time, $access_id)");
-			
-			if ($id!==false) {
-				$obj = get_metadata($id);
-				if (trigger_elgg_event('create', 'metadata', $obj)) {
-					return true;
-				} else {
-					delete_metadata($id);
-				}
+	function save() {
+		if ($this->id > 0) {
+			return update_metadata($this->id, $this->name, $this->value, $this->value_type, $this->owner_guid, $this->access_id);
+		} else {
+			$this->id = create_metadata($this->entity_guid, $this->name, $this->value, $this->value_type, $this->owner_guid, $this->access_id);
+			if (!$this->id) {
+				throw new IOException(sprintf(elgg_new('IOException:UnableToSaveNew'), get_class()));
 			}
-			
-		} else if ($existing) {
-// TODO: Check... are you sure you meant to do this Ben? :)			
-			$id = $existing->id;
-			delete_metadata($id);
-			
+			return $this->id;
 		}
-		
-		return $id;
 	}
-	
+
+	/**
+	 * Delete a given metadata.
+	 */
+	function delete() {
+		return delete_metadata($this->id);
+	}
+
 	/**
-	 * Update an item of metadata.
+	 * Get a url for this item of metadata.
 	 *
-	 * @param int $id
-	 * @param string $name
-	 * @param string $value
-	 * @param string $value_type
-	 * @param int $owner_guid
-	 * @param int $access_id
+	 * @return string
 	 */
-	function update_metadata($id, $name, $value, $value_type, $owner_guid, $access_id)
-	{
-		global $CONFIG;
+	public function getURL() {
+		return get_metadata_url($this->id);
+	}
 
-		$id = (int)$id;
+	// SYSTEM LOG INTERFACE ////////////////////////////////////////////////////////////
 
-		if (!$md = get_metadata($id)) return false;	
-		if (!$md->canEdit()) return false;
+	/**
+	 * For a given ID, return the object associated with it.
+	 * This is used by the river functionality primarily.
+	 * This is useful for checking access permissions etc on objects.
+	 */
+	public function getObjectFromID($id) {
+		return get_metadata($id);
+	}
+}
 
-		// If memcached then we invalidate the cache for this entry
-		static $metabyname_memcache;
-		if ((!$metabyname_memcache) && (is_memcache_available()))
-			$metabyname_memcache = new ElggMemcache('metabyname_memcache');
-		if ($metabyname_memcache) $metabyname_memcache->delete("{$md->entity_guid}:{$md->name_id}");
-		
-		//$name = sanitise_string(trim($name));
-		//$value = sanitise_string(trim($value));
-		$value_type = detect_extender_valuetype($value, sanitise_string(trim($value_type)));
-		
-		$owner_guid = (int)$owner_guid;
-		if ($owner_guid==0) $owner_guid = get_loggedin_userid();
-		
-		$access_id = (int)$access_id;
-		
-		$access = get_access_sql_suffix();
-		
-		// Support boolean types (as integers)
+/**
+ * Convert a database row to a new ElggMetadata
+ *
+ * @param stdClass $row
+ * @return stdClass or ElggMetadata
+ */
+function row_to_elggmetadata($row) {
+	if (!($row instanceof stdClass)) {
+		return $row;
+	}
+
+	return new ElggMetadata($row);
+}
+
+/**
+ * Get a specific item of metadata.
+ *
+ * @param $id int The item of metadata being retrieved.
+ */
+function get_metadata($id) {
+	global $CONFIG;
+
+	$id = (int)$id;
+	$access = get_access_sql_suffix("e");
+	$md_access = get_access_sql_suffix("m");
+
+	return row_to_elggmetadata(get_data_row("SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}metadata m JOIN {$CONFIG->dbprefix}entities e on e.guid = m.entity_guid JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id where m.id=$id and $access and $md_access"));
+}
+
+/**
+ * Removes metadata on an entity with a particular name, optionally with a given value.
+ *
+ * @param int $entity_guid The entity GUID
+ * @param string $name The name of the metadata
+ * @param string $value The optional value of the item (useful for removing a single item in a multiple set)
+ * @return true|false Depending on success
+ */
+function remove_metadata($entity_guid, $name, $value = "") {
+	global $CONFIG;
+	$entity_guid = (int) $entity_guid;
+	$name = sanitise_string($name);
+	$value = sanitise_string($value);
+
+	$query = "SELECT * from {$CONFIG->dbprefix}metadata WHERE entity_guid = $entity_guid and name_id=" . add_metastring($name);
+	if ($value!="") {
+		$query .= " and value_id=" . add_metastring($value);
+	}
+
+	if ($existing = get_data($query)) {
+		foreach($existing as $ex) {
+			delete_metadata($ex->id);
+		}
+		return true;
+	}
+
+	return false;
+}
+
+/**
+ * Create a new metadata object, or update an existing one.
+ *
+ * @param int $entity_guid
+ * @param string $name
+ * @param string $value
+ * @param string $value_type
+ * @param int $owner_guid
+ * @param int $access_id
+ * @param bool $allow_multiple
+ */
+function create_metadata($entity_guid, $name, $value, $value_type, $owner_guid, $access_id = ACCESS_PRIVATE, $allow_multiple = false) {
+	global $CONFIG;
+
+	$entity_guid = (int)$entity_guid;
+	//$name = sanitise_string(trim($name));
+	//$value = sanitise_string(trim($value));
+	$value_type = detect_extender_valuetype($value, sanitise_string(trim($value_type)));
+	$time = time();
+	$owner_guid = (int)$owner_guid;
+	$allow_multiple = (boolean)$allow_multiple;
+
+	if ($owner_guid==0) {
+		$owner_guid = get_loggedin_userid();
+	}
+
+	$access_id = (int)$access_id;
+
+	$id = false;
+
+	$existing = get_data_row("SELECT * from {$CONFIG->dbprefix}metadata WHERE entity_guid = $entity_guid and name_id=" . add_metastring($name) . " limit 1");
+	if (($existing) && (!$allow_multiple) && (isset($value))) {
+		$id = $existing->id;
+		$result = update_metadata($id, $name, $value, $value_type, $owner_guid, $access_id);
+
+		if (!$result) {
+			return false;
+		}
+	}
+	else if (isset($value)) {
+		// Support boolean types
 		if (is_bool($value)) {
-			if ($value)
+			if ($value) {
 				$value = 1;
-			else
+			} else {
 				$value = 0;
+			}
 		}
-		
-		// Add the metastring
+
+		// Add the metastrings
 		$value = add_metastring($value);
-		if (!$value) return false;
-		
+		if (!$value) {
+			return false;
+		}
+
 		$name = add_metastring($name);
-		if (!$name) return false;
+		if (!$name) {
+			return false;
+		}
+
+		// If ok then add it
+		$id = insert_data("INSERT into {$CONFIG->dbprefix}metadata (entity_guid, name_id, value_id, value_type, owner_guid, time_created, access_id) VALUES ($entity_guid, '$name','$value','$value_type', $owner_guid, $time, $access_id)");
 
-				// If ok then add it
-		$result = update_data("UPDATE {$CONFIG->dbprefix}metadata set value_id='$value', value_type='$value_type', access_id=$access_id, owner_guid=$owner_guid where id=$id and name_id='$name'");
-		if ($result!==false) {
+		if ($id!==false) {
 			$obj = get_metadata($id);
-			if (trigger_elgg_event('update', 'metadata', $obj)) {
+			if (trigger_elgg_event('create', 'metadata', $obj)) {
 				return true;
 			} else {
 				delete_metadata($id);
 			}
 		}
-			
-		return $result;
+
+	} else if ($existing) {
+		// TODO: Check... are you sure you meant to do this Ben? :)
+		$id = $existing->id;
+		delete_metadata($id);
 	}
-	
-	/**
-	 * This function creates metadata from an associative array of "key => value" pairs.
-	 * 
-	 * @param int $entity_guid
-	 * @param string $name_and_values
-	 * @param string $value_type
-	 * @param int $owner_guid
-	 * @param int $access_id
-	 * @param bool $allow_multiple
-	 */
-	function create_metadata_from_array($entity_guid, array $name_and_values, $value_type, $owner_guid, $access_id = ACCESS_PRIVATE, $allow_multiple = false)
-	{
-		foreach ($name_and_values as $k => $v)
-			if (!create_metadata($entity_guid, $k, $v, $value_type, $owner_guid, $access_id, $allow_multiple)) return false;
-		
-		return true;
+
+	return $id;
+}
+
+/**
+ * Update an item of metadata.
+ *
+ * @param int $id
+ * @param string $name
+ * @param string $value
+ * @param string $value_type
+ * @param int $owner_guid
+ * @param int $access_id
+ */
+function update_metadata($id, $name, $value, $value_type, $owner_guid, $access_id) {
+	global $CONFIG;
+
+	$id = (int)$id;
+
+	if (!$md = get_metadata($id)) {
+		return false;
 	}
-	
-	/**
-	 * Delete an item of metadata, where the current user has access.
-	 * 
-	 * @param $id int The item of metadata to delete.
-	 */
-	function delete_metadata($id)
-	{
-		global $CONFIG;
-
-		$id = (int)$id;
-		$metadata = get_metadata($id);
-		
-		if ($metadata) {
-			// Tidy up if memcache is enabled.
-			static $metabyname_memcache;
-			if ((!$metabyname_memcache) && (is_memcache_available()))
-				$metabyname_memcache = new ElggMemcache('metabyname_memcache');
-			if ($metabyname_memcache) $metabyname_memcache->delete("{$metadata->entity_guid}:{$metadata->name_id}");
-			
-			if (($metadata->canEdit()) && (trigger_elgg_event('delete', 'metadata', $metadata)))
-				return delete_data("DELETE from {$CONFIG->dbprefix}metadata where id=$id");
-		}
-		
+	if (!$md->canEdit()) {
 		return false;
 	}
-	
-	/**
-	 * Return the metadata values that match your query.
-	 * 
-	 * @param string $meta_name
-	 * @return mixed either a value, an array of ElggMetadata or false.
-	 */
-	function get_metadata_byname($entity_guid,  $meta_name)
-	{
-		global $CONFIG;
-	
-		$meta_name = get_metastring_id($meta_name);
-		
-		if (empty($meta_name)) return false;
-		
-		$entity_guid = (int)$entity_guid;
-		$access = get_access_sql_suffix("e");
-		$md_access = get_access_sql_suffix("m");
-		
-		// If memcache is available then cache this (cache only by name for now since this is the most common query)
-		$meta = null;
-		static $metabyname_memcache;
-		if ((!$metabyname_memcache) && (is_memcache_available()))
-			$metabyname_memcache = new ElggMemcache('metabyname_memcache');
-		if ($metabyname_memcache) $meta = $metabyname_memcache->load("{$entity_guid}:{$meta_name}");
-		if ($meta) return $meta;	
 
-		$result = get_data("SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}metadata m JOIN {$CONFIG->dbprefix}entities e ON e.guid = m.entity_guid JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id where m.entity_guid=$entity_guid and m.name_id='$meta_name' and $access and $md_access", "row_to_elggmetadata");
-		if (!$result) 
-			return false;
-			
-		// Cache if memcache available
-		if ($metabyname_memcache)
-		{ 
-			if (count($result) == 1) $r = $result[0]; else $r = $result;
-			$metabyname_memcache->setDefaultExpiry(3600); // This is a bit of a hack - we shorten the expiry on object metadata so that it'll be gone in an hour. This means that deletions and more importantly updates will filter through eventually.
-			$metabyname_memcache->save("{$entity_guid}:{$meta_name}", $r);
-			
-		}
-		if (count($result) == 1)
-			return $result[0];
-			
-		return $result;
+	// If memcached then we invalidate the cache for this entry
+	static $metabyname_memcache;
+	if ((!$metabyname_memcache) && (is_memcache_available())) {
+		$metabyname_memcache = new ElggMemcache('metabyname_memcache');
 	}
-	
-	/**
-	 * Return all the metadata for a given GUID.
-	 * 
-	 * @param int $entity_guid
-	 */
-	function get_metadata_for_entity($entity_guid)
-	{
-		global $CONFIG;
-	
-		$entity_guid = (int)$entity_guid;
-		$access = get_access_sql_suffix("e");
-		$md_access = get_access_sql_suffix("m");
-		
-		return get_data("SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}metadata m JOIN {$CONFIG->dbprefix}entities e ON e.guid = m.entity_guid JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id where m.entity_guid=$entity_guid and $access and $md_access", "row_to_elggmetadata");
+
+	if ($metabyname_memcache) {
+		$metabyname_memcache->delete("{$md->entity_guid}:{$md->name_id}");
 	}
 
-	/**
-	 * Get the metadata where the entities they are referring to match a given criteria.
-	 * 
-	 * @param mixed $meta_name 
-	 * @param mixed $meta_value
-	 * @param string $entity_type The type of entity to look for, eg 'site' or 'object'
-	 * @param string $entity_subtype The subtype of the entity.
-	 * @param int $limit 
-	 * @param int $offset
-	 * @param string $order_by Optional ordering.
-	 * @param int $site_guid The site to get entities for. Leave as 0 (default) for the current site; -1 for all sites.
-	 */
-	function find_metadata($meta_name = "", $meta_value = "", $entity_type = "", $entity_subtype = "", $limit = 10, $offset = 0, $order_by = "", $site_guid = 0)
-	{
-		global $CONFIG;
-		
-		$meta_n = get_metastring_id($meta_name);
-		$meta_v = get_metastring_id($meta_value);
-		
-		$entity_type = sanitise_string($entity_type);
-		$entity_subtype = get_subtype_id($entity_type, $entity_subtype);
-		$limit = (int)$limit;
-		$offset = (int)$offset;
-		if ($order_by == "") $order_by = "e.time_created desc";
-		$order_by = sanitise_string($order_by);
-		$site_guid = (int) $site_guid;
-		if ($site_guid == 0)
-			$site_guid = $CONFIG->site_guid;
-			
-			
-		$where = array();
-		
-		if ($entity_type!="")
-			$where[] = "e.type='$entity_type'";
-		if ($entity_subtype)
-			$where[] = "e.subtype=$entity_subtype";
-		if ($meta_name!="") {
-			if (!$meta_v) return false; // The value is set, but we didn't get a value... so something went wrong.
-			$where[] = "m.name_id='$meta_n'";
-		}
-		if ($meta_value!="") {
-			if (!$meta_v) return false; // The value is set, but we didn't get a value... so something went wrong.
-			$where[] = "m.value_id='$meta_v'";
-		}
-		if ($site_guid > 0)
-			$where[] = "e.site_guid = {$site_guid}";
-		
-		$query = "SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}entities e JOIN {$CONFIG->dbprefix}metadata m on e.guid = m.entity_guid JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id where";
-		foreach ($where as $w)
-			$query .= " $w and ";
-		$query .= get_access_sql_suffix("e"); // Add access controls
-		$query .= ' and ' . get_access_sql_suffix("m"); // Add access controls
-		$query .= " order by $order_by limit $offset, $limit"; // Add order and limit
+	//$name = sanitise_string(trim($name));
+	//$value = sanitise_string(trim($value));
+	$value_type = detect_extender_valuetype($value, sanitise_string(trim($value_type)));
 
-		return get_data($query, "row_to_elggmetadata");
+	$owner_guid = (int)$owner_guid;
+	if ($owner_guid==0) {
+		$owner_guid = get_loggedin_userid();
 	}
-	
-	/**
-	 * Return a list of entities based on the given search criteria.
-	 * 
-	 * @param mixed $meta_name 
-	 * @param mixed $meta_value
-	 * @param string $entity_type The type of entity to look for, eg 'site' or 'object'
-	 * @param string $entity_subtype The subtype of the entity.
-	 * @param int $limit 
-	 * @param int $offset
-	 * @param string $order_by Optional ordering.
-	 * @param int $site_guid The site to get entities for. Leave as 0 (default) for the current site; -1 for all sites.
-	 * @param true|false $count If set to true, returns the total number of entities rather than a list. (Default: false)
-	 * 
-	 * @return int|array A list of entities, or a count if $count is set to true
-	 */
-	function get_entities_from_metadata($meta_name, $meta_value = "", $entity_type = "", $entity_subtype = "", $owner_guid = 0, $limit = 10, $offset = 0, $order_by = "", $site_guid = 0, $count = false)
-	{
-		global $CONFIG;
-		
-		$meta_n = get_metastring_id($meta_name);
-		$meta_v = get_metastring_id($meta_value);
-			
-		$entity_type = sanitise_string($entity_type);
-		$entity_subtype = get_subtype_id($entity_type, $entity_subtype);
-		$limit = (int)$limit;
-		$offset = (int)$offset;
-		if ($order_by == "") 
-			$order_by = "e.time_created desc";
-		else
-			$order_by = "e.time_created, {$order_by}";
-		$order_by = sanitise_string($order_by);
-		$site_guid = (int) $site_guid;
-		if ((is_array($owner_guid) && (count($owner_guid)))) {
-			foreach($owner_guid as $key => $guid) {
-				$owner_guid[$key] = (int) $guid;
-			}
-		} else {
-			$owner_guid = (int) $owner_guid;
-		}
-		if ($site_guid == 0)
-			$site_guid = $CONFIG->site_guid;
-			
-		//$access = get_access_list();
-			
-		$where = array();
-		
-		if ($entity_type!=="")
-			$where[] = "e.type='$entity_type'";
-		if ($entity_subtype)
-			$where[] = "e.subtype=$entity_subtype";
-		if ($meta_name!=="")
-			$where[] = "m.name_id='$meta_n'";
-		if ($meta_value!=="")
-			$where[] = "m.value_id='$meta_v'";
-		if ($site_guid > 0)
-			$where[] = "e.site_guid = {$site_guid}";
-		if (is_array($owner_guid)) {
-			$where[] = "e.container_guid in (".implode(",",$owner_guid).")";
-		} else if ($owner_guid > 0)
-			$where[] = "e.container_guid = {$owner_guid}";
-		
-		if (!$count) {
-			$query = "SELECT distinct e.* "; 
-		} else {
-			$query = "SELECT count(distinct e.guid) as total ";
-		}
-			
-		$query .= "from {$CONFIG->dbprefix}entities e JOIN {$CONFIG->dbprefix}metadata m on e.guid = m.entity_guid where";
-		foreach ($where as $w)
-			$query .= " $w and ";
-		$query .= get_access_sql_suffix("e"); // Add access controls
-		$query .= ' and ' . get_access_sql_suffix("m"); // Add access controls
-		
-		if (!$count) {
-			$query .= " order by $order_by limit $offset, $limit"; // Add order and limit
-			return get_data($query, "entity_row_to_elggstar");
+
+	$access_id = (int)$access_id;
+
+	$access = get_access_sql_suffix();
+
+	// Support boolean types (as integers)
+	if (is_bool($value)) {
+		if ($value) {
+			$value = 1;
 		} else {
-			if ($row = get_data_row($query))
-				return $row->total;
+			$value = 0;
 		}
+	}
+
+	// Add the metastring
+	$value = add_metastring($value);
+	if (!$value) {
 		return false;
 	}
-	
-	/**
-	 * Return a list of entities suitable for display based on the given search criteria.
-	 * 
-	 * @see elgg_view_entity_list
-	 * 
-	 * @param mixed $meta_name Metadata name to search on
-	 * @param mixed $meta_value The value to match, optionally
-	 * @param string $entity_type The type of entity to look for, eg 'site' or 'object'
-	 * @param string $entity_subtype The subtype of the entity
-	 * @param int $limit Number of entities to display per page
-	 * @param true|false $fullview Whether or not to display the full view (default: true)
-	 * @param true|false $viewtypetoggle Whether or not to allow users to toggle to the gallery view. Default: true
-	 * @param true|false $pagination Display pagination? Default: true
-	 * 
-	 * @return string A list of entities suitable for display
-	 */
-	function list_entities_from_metadata($meta_name, $meta_value = "", $entity_type = "", $entity_subtype = "", $owner_guid = 0, $limit = 10, $fullview = true, $viewtypetoggle = true, $pagination = true) {
-		
-		$offset = (int) get_input('offset');
-		$limit = (int) $limit;
-		$count = get_entities_from_metadata($meta_name, $meta_value, $entity_type, $entity_subtype, $owner_guid, $limit, $offset, "", 0, true);
-		$entities = get_entities_from_metadata($meta_name, $meta_value, $entity_type, $entity_subtype, $owner_guid, $limit, $offset, "", 0, false);
-		
-		return elgg_view_entity_list($entities, $count, $offset, $limit, $fullview, $viewtypetoggle, $pagination);
-		
+
+	$name = add_metastring($name);
+	if (!$name) {
+		return false;
 	}
 
-	/**
-	 * Returns a list of entities based on the given search criteria.
-	 *
-	 * @param array $meta_array Array of 'name' => 'value' pairs
-	 * @param string $entity_type The type of entity to look for, eg 'site' or 'object'
-	 * @param string $entity_subtype The subtype of the entity.
-	 * @param int $limit 
-	 * @param int $offset
-	 * @param string $order_by Optional ordering.
-	 * @param int $site_guid The site to get entities for. Leave as 0 (default) for the current site; -1 for all sites.
-	 * @param true|false $count If set to true, returns the total number of entities rather than a list. (Default: false)
-	 * @param string $meta_array_operator Operator used for joining the metadata array together
-	 * @return int|array List of ElggEntities, or the total number if count is set to false
-	 */
-	function get_entities_from_metadata_multi($meta_array, $entity_type = "", $entity_subtype = "", $owner_guid = 0, $limit = 10, $offset = 0, $order_by = "", $site_guid = 0, $count = false, $meta_array_operator = 'and')
-	{
-		global $CONFIG;
-		
-		if (!is_array($meta_array) || sizeof($meta_array) == 0) {
+	// If ok then add it
+	$result = update_data("UPDATE {$CONFIG->dbprefix}metadata set value_id='$value', value_type='$value_type', access_id=$access_id, owner_guid=$owner_guid where id=$id and name_id='$name'");
+	if ($result!==false) {
+		$obj = get_metadata($id);
+		if (trigger_elgg_event('update', 'metadata', $obj)) {
+			return true;
+		} else {
+			delete_metadata($id);
+		}
+	}
+
+	return $result;
+}
+
+/**
+ * This function creates metadata from an associative array of "key => value" pairs.
+ *
+ * @param int $entity_guid
+ * @param string $name_and_values
+ * @param string $value_type
+ * @param int $owner_guid
+ * @param int $access_id
+ * @param bool $allow_multiple
+ */
+function create_metadata_from_array($entity_guid, array $name_and_values, $value_type, $owner_guid, $access_id = ACCESS_PRIVATE, $allow_multiple = false) {
+	foreach ($name_and_values as $k => $v) {
+		if (!create_metadata($entity_guid, $k, $v, $value_type, $owner_guid, $access_id, $allow_multiple)) {
 			return false;
 		}
-		
-		$where = array();
-		
-		$mindex = 1;
-		$join = "";
-		$metawhere = array();
-		$meta_array_operator = sanitise_string($meta_array_operator);
-		foreach($meta_array as $meta_name => $meta_value) {
-			$meta_n = get_metastring_id($meta_name);
-			$meta_v = get_metastring_id($meta_value);
-			$join .= " JOIN {$CONFIG->dbprefix}metadata m{$mindex} on e.guid = m{$mindex}.entity_guid "; 
-			/*if ($meta_name!=="")
-				$where[] = "m{$mindex}.name_id='$meta_n'";
-			if ($meta_value!=="")
-				$where[] = "m{$mindex}.value_id='$meta_v'";*/
-			$metawhere[] = "(m{$mindex}.name_id='$meta_n' AND m{$mindex}.value_id='$meta_v')";
-			$mindex++;
+	}
+	return true;
+}
+
+/**
+ * Delete an item of metadata, where the current user has access.
+ *
+ * @param $id int The item of metadata to delete.
+ */
+function delete_metadata($id) {
+	global $CONFIG;
+
+	$id = (int)$id;
+	$metadata = get_metadata($id);
+
+	if ($metadata) {
+		// Tidy up if memcache is enabled.
+		static $metabyname_memcache;
+		if ((!$metabyname_memcache) && (is_memcache_available())) {
+			$metabyname_memcache = new ElggMemcache('metabyname_memcache');
 		}
-		$where[] = "(".implode($meta_array_operator, $metawhere).")";
-			
-		$entity_type = sanitise_string($entity_type);
-		$entity_subtype = get_subtype_id($entity_type, $entity_subtype);
-		$limit = (int)$limit;
-		$offset = (int)$offset;
-		if ($order_by == "") $order_by = "e.time_created desc";
-		$order_by = sanitise_string($order_by);
-		if ((is_array($owner_guid) && (count($owner_guid)))) {
-			foreach($owner_guid as $key => $guid) {
-				$owner_guid[$key] = (int) $guid;
-			}
-		} else {
-			$owner_guid = (int) $owner_guid;
+
+		if ($metabyname_memcache) {
+			$metabyname_memcache->delete("{$metadata->entity_guid}:{$metadata->name_id}");
 		}
-		
-		$site_guid = (int) $site_guid;
-		if ($site_guid == 0)
-			$site_guid = $CONFIG->site_guid;
-			
-		//$access = get_access_list();
-		
-		if ($entity_type!="")
-			$where[] = "e.type = '{$entity_type}'";
-		if ($entity_subtype)
-			$where[] = "e.subtype = {$entity_subtype}";
-		if ($site_guid > 0)
-			$where[] = "e.site_guid = {$site_guid}";
-		if (is_array($owner_guid)) {
-			$where[] = "e.container_guid in (".implode(",",$owner_guid).")";
-		} else if ($owner_guid > 0)
-			$where[] = "e.container_guid = {$owner_guid}";
-		//if ($owner_guid > 0)
-		//	$where[] = "e.container_guid = {$owner_guid}";
-		
-		if ($count) {
-			$query = "SELECT count(distinct e.guid) as total ";
+
+		if (($metadata->canEdit()) && (trigger_elgg_event('delete', 'metadata', $metadata))) {
+			return delete_data("DELETE from {$CONFIG->dbprefix}metadata where id=$id");
+		}
+	}
+
+	return false;
+}
+
+/**
+ * Return the metadata values that match your query.
+ *
+ * @param string $meta_name
+ * @return mixed either a value, an array of ElggMetadata or false.
+ */
+function get_metadata_byname($entity_guid,  $meta_name) {
+	global $CONFIG;
+
+	$meta_name = get_metastring_id($meta_name);
+
+	if (empty($meta_name)) {
+		return false;
+	}
+
+	$entity_guid = (int)$entity_guid;
+	$access = get_access_sql_suffix("e");
+	$md_access = get_access_sql_suffix("m");
+
+	// If memcache is available then cache this (cache only by name for now since this is the most common query)
+	$meta = null;
+	static $metabyname_memcache;
+	if ((!$metabyname_memcache) && (is_memcache_available())) {
+		$metabyname_memcache = new ElggMemcache('metabyname_memcache');
+	}
+	if ($metabyname_memcache) {
+		$meta = $metabyname_memcache->load("{$entity_guid}:{$meta_name}");
+	}
+	if ($meta) {
+		return $meta;
+	}
+
+	$result = get_data("SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}metadata m JOIN {$CONFIG->dbprefix}entities e ON e.guid = m.entity_guid JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id where m.entity_guid=$entity_guid and m.name_id='$meta_name' and $access and $md_access", "row_to_elggmetadata");
+	if (!$result) {
+		return false;
+	}
+
+	// Cache if memcache available
+	if ($metabyname_memcache) {
+		if (count($result) == 1) {
+			$r = $result[0];
 		} else {
-			$query = "SELECT distinct e.* "; 
+			$r = $result;
 		}
-			
-		$query .= " from {$CONFIG->dbprefix}entities e {$join} where";
-		foreach ($where as $w)
-			$query .= " $w and ";
-		$query .= get_access_sql_suffix("e"); // Add access controls
-	
-		$mindex = 1;
-		foreach($meta_array as $meta_name => $meta_value) {
-			$query .= ' and ' . get_access_sql_suffix("m{$mindex}"); // Add access controls
-			$mindex++;
+		// This is a bit of a hack - we shorten the expiry on object
+		// metadata so that it'll be gone in an hour. This means that
+		// deletions and more importantly updates will filter through eventually.
+		$metabyname_memcache->setDefaultExpiry(3600);
+		$metabyname_memcache->save("{$entity_guid}:{$meta_name}", $r);
+	}
+	if (count($result) == 1) {
+		return $result[0];
+	}
+
+	return $result;
+}
+
+/**
+ * Return all the metadata for a given GUID.
+ *
+ * @param int $entity_guid
+ */
+function get_metadata_for_entity($entity_guid) {
+	global $CONFIG;
+
+	$entity_guid = (int)$entity_guid;
+	$access = get_access_sql_suffix("e");
+	$md_access = get_access_sql_suffix("m");
+
+	return get_data("SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}metadata m JOIN {$CONFIG->dbprefix}entities e ON e.guid = m.entity_guid JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id where m.entity_guid=$entity_guid and $access and $md_access", "row_to_elggmetadata");
+}
+
+/**
+ * Get the metadata where the entities they are referring to match a given criteria.
+ *
+ * @param mixed $meta_name
+ * @param mixed $meta_value
+ * @param string $entity_type The type of entity to look for, eg 'site' or 'object'
+ * @param string $entity_subtype The subtype of the entity.
+ * @param int $limit
+ * @param int $offset
+ * @param string $order_by Optional ordering.
+ * @param int $site_guid The site to get entities for. Leave as 0 (default) for the current site; -1 for all sites.
+ */
+function find_metadata($meta_name = "", $meta_value = "", $entity_type = "", $entity_subtype = "", $limit = 10, $offset = 0, $order_by = "", $site_guid = 0) {
+	global $CONFIG;
+
+	$meta_n = get_metastring_id($meta_name);
+	$meta_v = get_metastring_id($meta_value);
+
+	$entity_type = sanitise_string($entity_type);
+	$entity_subtype = get_subtype_id($entity_type, $entity_subtype);
+	$limit = (int)$limit;
+	$offset = (int)$offset;
+	if ($order_by == "") {
+		$order_by = "e.time_created desc";
+	}
+
+	$order_by = sanitise_string($order_by);
+	$site_guid = (int) $site_guid;
+	if ($site_guid == 0) {
+		$site_guid = $CONFIG->site_guid;
+	}
+
+	$where = array();
+
+	if ($entity_type!="") {
+		$where[] = "e.type='$entity_type'";
+	}
+
+	if ($entity_subtype) {
+		$where[] = "e.subtype=$entity_subtype";
+	}
+
+	if ($meta_name!="") {
+		if (!$meta_v) {
+			// The value is set, but we didn't get a value... so something went wrong.
+			return false;
 		}
-		
-		if (!$count) {
-			$query .= " order by $order_by limit $offset, $limit"; // Add order and limit
-			return get_data($query, "entity_row_to_elggstar");
-		} else {
-			if ($count = get_data_row($query)) {
-				return $count->total;
-			}
+		$where[] = "m.name_id='$meta_n'";
+	}
+	if ($meta_value!="") {
+		// The value is set, but we didn't get a value... so something went wrong.
+		if (!$meta_v) {
+			return false;
 		}
-		return false;
+		$where[] = "m.value_id='$meta_v'";
 	}
-	
-	/**
-	 * Returns a viewable list of entities based on the given search criteria.
-	 *
-	 * @see elgg_view_entity_list
-	 * 
-	 * @param array $meta_array Array of 'name' => 'value' pairs
-	 * @param string $entity_type The type of entity to look for, eg 'site' or 'object'
-	 * @param string $entity_subtype The subtype of the entity.
-	 * @param int $limit 
-	 * @param int $offset
-	 * @param string $order_by Optional ordering.
-	 * @param true|false $fullview Whether or not to display the full view (default: true)
-	 * @param true|false $viewtypetoggle Whether or not to allow users to toggle to the gallery view. Default: true
-	 * @param true|false $pagination Display pagination? Default: true
-	 * @return string List of ElggEntities suitable for display
-	 */
-	function list_entities_from_metadata_multi($meta_array, $entity_type = "", $entity_subtype = "", $owner_guid = 0, $limit = 10, $fullview = true, $viewtypetoggle = true, $pagination = true) {
-		
-		$offset = (int) get_input('offset');
-		$limit = (int) $limit;
-		$count = get_entities_from_metadata_multi($meta_array, $entity_type, $entity_subtype, $owner_guid, $limit, $offset, "", $site_guid, true);
-		$entities = get_entities_from_metadata_multi($meta_array, $entity_type, $entity_subtype, $owner_guid, $limit, $offset, "", $site_guid, false);
-	
-		return elgg_view_entity_list($entities, $count, $offset, $limit, $fullview, $viewtypetoggle, $pagination);
-		
-	}
-	
-	/**
-	 * Clear all the metadata for a given entity, assuming you have access to that metadata.
-	 * 
-	 * @param int $guid
-	 */
-	function clear_metadata($entity_guid)
-	{
-		global $CONFIG;
-		
-		$entity_guid = (int)$entity_guid;
-		if ($entity = get_entity($entity_guid)) {
-			if ($entity->canEdit())
-				return delete_data("DELETE from {$CONFIG->dbprefix}metadata where entity_guid={$entity_guid}");
+	if ($site_guid > 0) {
+		$where[] = "e.site_guid = {$site_guid}";
+	}
+
+	$query = "SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}entities e JOIN {$CONFIG->dbprefix}metadata m on e.guid = m.entity_guid JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id where";
+	foreach ($where as $w) {
+		$query .= " $w and ";
+	}
+	$query .= get_access_sql_suffix("e"); // Add access controls
+	$query .= ' and ' . get_access_sql_suffix("m"); // Add access controls
+	$query .= " order by $order_by limit $offset, $limit"; // Add order and limit
+
+	return get_data($query, "row_to_elggmetadata");
+}
+
+/**
+ * Return a list of entities based on the given search criteria.
+ *
+ * @param mixed $meta_name
+ * @param mixed $meta_value
+ * @param string $entity_type The type of entity to look for, eg 'site' or 'object'
+ * @param string $entity_subtype The subtype of the entity.
+ * @param int $limit
+ * @param int $offset
+ * @param string $order_by Optional ordering.
+ * @param int $site_guid The site to get entities for. Leave as 0 (default) for the current site; -1 for all sites.
+ * @param true|false $count If set to true, returns the total number of entities rather than a list. (Default: false)
+ *
+ * @return int|array A list of entities, or a count if $count is set to true
+ */
+function get_entities_from_metadata($meta_name, $meta_value = "", $entity_type = "", $entity_subtype = "", $owner_guid = 0, $limit = 10, $offset = 0, $order_by = "", $site_guid = 0, $count = false) {
+	global $CONFIG;
+
+	$meta_n = get_metastring_id($meta_name);
+	$meta_v = get_metastring_id($meta_value);
+
+	$entity_type = sanitise_string($entity_type);
+	$entity_subtype = get_subtype_id($entity_type, $entity_subtype);
+	$limit = (int)$limit;
+	$offset = (int)$offset;
+	if ($order_by == "") {
+		$order_by = "e.time_created desc";
+	} else {
+		$order_by = "e.time_created, {$order_by}";
+	}
+	$order_by = sanitise_string($order_by);
+	$site_guid = (int) $site_guid;
+	if ((is_array($owner_guid) && (count($owner_guid)))) {
+		foreach($owner_guid as $key => $guid) {
+			$owner_guid[$key] = (int) $guid;
 		}
+	} else {
+		$owner_guid = (int) $owner_guid;
+	}
+	if ($site_guid == 0) {
+		$site_guid = $CONFIG->site_guid;
+	}
+
+	//$access = get_access_list();
+
+	$where = array();
+
+	if ($entity_type!=="") {
+		$where[] = "e.type='$entity_type'";
+	}
+
+	if ($entity_subtype) {
+		$where[] = "e.subtype=$entity_subtype";
+	}
+	if ($meta_name!=="") {
+		$where[] = "m.name_id='$meta_n'";
+	}
+	if ($meta_value!=="") {
+		$where[] = "m.value_id='$meta_v'";
+	}
+	if ($site_guid > 0) {
+		$where[] = "e.site_guid = {$site_guid}";
+	}
+	if (is_array($owner_guid)) {
+		$where[] = "e.container_guid in (".implode(",",$owner_guid).")";
+	} else if ($owner_guid > 0) {
+		$where[] = "e.container_guid = {$owner_guid}";
+	}
+
+	if (!$count) {
+		$query = "SELECT distinct e.* ";
+	} else {
+		$query = "SELECT count(distinct e.guid) as total ";
+	}
+
+	$query .= "from {$CONFIG->dbprefix}entities e JOIN {$CONFIG->dbprefix}metadata m on e.guid = m.entity_guid where";
+	foreach ($where as $w) {
+		$query .= " $w and ";
+	}
+	$query .= get_access_sql_suffix("e"); // Add access controls
+	$query .= ' and ' . get_access_sql_suffix("m"); // Add access controls
+
+	if (!$count) {
+		$query .= " order by $order_by limit $offset, $limit"; // Add order and limit
+		return get_data($query, "entity_row_to_elggstar");
+	} else {
+		if ($row = get_data_row($query)) {
+			return $row->total;
+		}
+	}
+	return false;
+}
+
+/**
+ * Return a list of entities suitable for display based on the given search criteria.
+ *
+ * @see elgg_view_entity_list
+ *
+ * @param mixed $meta_name Metadata name to search on
+ * @param mixed $meta_value The value to match, optionally
+ * @param string $entity_type The type of entity to look for, eg 'site' or 'object'
+ * @param string $entity_subtype The subtype of the entity
+ * @param int $limit Number of entities to display per page
+ * @param true|false $fullview Whether or not to display the full view (default: true)
+ * @param true|false $viewtypetoggle Whether or not to allow users to toggle to the gallery view. Default: true
+ * @param true|false $pagination Display pagination? Default: true
+ *
+ * @return string A list of entities suitable for display
+ */
+function list_entities_from_metadata($meta_name, $meta_value = "", $entity_type = "", $entity_subtype = "", $owner_guid = 0, $limit = 10, $fullview = true, $viewtypetoggle = true, $pagination = true) {
+	$offset = (int) get_input('offset');
+	$limit = (int) $limit;
+	$count = get_entities_from_metadata($meta_name, $meta_value, $entity_type, $entity_subtype, $owner_guid, $limit, $offset, "", 0, true);
+	$entities = get_entities_from_metadata($meta_name, $meta_value, $entity_type, $entity_subtype, $owner_guid, $limit, $offset, "", 0, false);
+
+	return elgg_view_entity_list($entities, $count, $offset, $limit, $fullview, $viewtypetoggle, $pagination);
+}
+
+/**
+ * Returns a list of entities based on the given search criteria.
+ *
+ * @param array $meta_array Array of 'name' => 'value' pairs
+ * @param string $entity_type The type of entity to look for, eg 'site' or 'object'
+ * @param string $entity_subtype The subtype of the entity.
+ * @param int $limit
+ * @param int $offset
+ * @param string $order_by Optional ordering.
+ * @param int $site_guid The site to get entities for. Leave as 0 (default) for the current site; -1 for all sites.
+ * @param true|false $count If set to true, returns the total number of entities rather than a list. (Default: false)
+ * @param string $meta_array_operator Operator used for joining the metadata array together
+ * @return int|array List of ElggEntities, or the total number if count is set to false
+ */
+function get_entities_from_metadata_multi($meta_array, $entity_type = "", $entity_subtype = "", $owner_guid = 0, $limit = 10, $offset = 0, $order_by = "", $site_guid = 0, $count = false, $meta_array_operator = 'and') {
+	global $CONFIG;
+
+	if (!is_array($meta_array) || sizeof($meta_array) == 0) {
 		return false;
 	}
-	
-	/**
-	 * Clear all annotations belonging to a given owner_guid
-	 *
-	 * @param int $owner_guid The owner
-	 */
-	function clear_metadata_by_owner($owner_guid)
-	{
-		global $CONFIG;
-		
-		$owner_guid = (int)$owner_guid;
-		
-		$metas = get_data("SELECT id from {$CONFIG->dbprefix}metadata WHERE owner_guid=$owner_guid");
-		$deleted = 0;
-		
-		foreach ($metas as $id)
-		{
-			if (delete_metadata($id->id)) // Is this the best way?
-				$deleted++;
+
+	$where = array();
+
+	$mindex = 1;
+	$join = "";
+	$metawhere = array();
+	$meta_array_operator = sanitise_string($meta_array_operator);
+	foreach($meta_array as $meta_name => $meta_value) {
+		$meta_n = get_metastring_id($meta_name);
+		$meta_v = get_metastring_id($meta_value);
+		$join .= " JOIN {$CONFIG->dbprefix}metadata m{$mindex} on e.guid = m{$mindex}.entity_guid ";
+		/*if ($meta_name!=="")
+			$where[] = "m{$mindex}.name_id='$meta_n'";
+		if ($meta_value!=="")
+			$where[] = "m{$mindex}.value_id='$meta_v'";*/
+		$metawhere[] = "(m{$mindex}.name_id='$meta_n' AND m{$mindex}.value_id='$meta_v')";
+		$mindex++;
+	}
+	$where[] = "(".implode($meta_array_operator, $metawhere).")";
+
+	$entity_type = sanitise_string($entity_type);
+	$entity_subtype = get_subtype_id($entity_type, $entity_subtype);
+	$limit = (int)$limit;
+	$offset = (int)$offset;
+	if ($order_by == "") {
+		$order_by = "e.time_created desc";
+	}
+	$order_by = sanitise_string($order_by);
+	if ((is_array($owner_guid) && (count($owner_guid)))) {
+		foreach($owner_guid as $key => $guid) {
+			$owner_guid[$key] = (int) $guid;
 		}
-		
-		return $deleted;
+	} else {
+		$owner_guid = (int) $owner_guid;
 	}
-	
-	/**
-	 * Handler called by trigger_plugin_hook on the "export" event.
-	 */
-	function export_metadata_plugin_hook($hook, $entity_type, $returnvalue, $params)
-	{
-		// Sanity check values
-		if ((!is_array($params)) && (!isset($params['guid'])))
-			throw new InvalidParameterException(elgg_echo('InvalidParameterException:GUIDNotForExport'));
-			
-		if (!is_array($returnvalue))
-			throw new InvalidParameterException(elgg_echo('InvalidParameterException:NonArrayReturnValue'));
-		
-		$guid = (int)$params['guid'];
-		$name = $params['name'];	
-		
-		$result = get_metadata_for_entity($guid); 
-				
-		if ($result)
-		{
-			foreach ($result as $r)
-				$returnvalue[] = $r->export();
+
+	$site_guid = (int) $site_guid;
+	if ($site_guid == 0) {
+		$site_guid = $CONFIG->site_guid;
+	}
+
+	//$access = get_access_list();
+
+	if ($entity_type!="") {
+		$where[] = "e.type = '{$entity_type}'";
+	}
+
+	if ($entity_subtype) {
+		$where[] = "e.subtype = {$entity_subtype}";
+	}
+
+	if ($site_guid > 0) {
+		$where[] = "e.site_guid = {$site_guid}";
+	}
+
+	if (is_array($owner_guid)) {
+		$where[] = "e.container_guid in (".implode(",",$owner_guid).")";
+	} else if ($owner_guid > 0) {
+		$where[] = "e.container_guid = {$owner_guid}";
+	}
+
+	//if ($owner_guid > 0)
+	//	$where[] = "e.container_guid = {$owner_guid}";
+
+	if ($count) {
+		$query = "SELECT count(distinct e.guid) as total ";
+	} else {
+		$query = "SELECT distinct e.* ";
+	}
+
+	$query .= " from {$CONFIG->dbprefix}entities e {$join} where";
+	foreach ($where as $w) {
+		$query .= " $w and ";
+	}
+	$query .= get_access_sql_suffix("e"); // Add access controls
+
+	$mindex = 1;
+	foreach($meta_array as $meta_name => $meta_value) {
+		$query .= ' and ' . get_access_sql_suffix("m{$mindex}"); // Add access controls
+		$mindex++;
+	}
+
+	if (!$count) {
+		$query .= " order by $order_by limit $offset, $limit"; // Add order and limit
+		return get_data($query, "entity_row_to_elggstar");
+	} else {
+		if ($count = get_data_row($query)) {
+			return $count->total;
 		}
-		
-		return $returnvalue;
 	}
-	
-	/**
-	 * Takes in a comma-separated string and returns an array of tags which have been trimmed and set to lower case
-	 *
-	 * @param string $string Comma-separated tag string
-	 * @return array|false An array of strings, or false on failure
-	 */
-	function string_to_tag_array($string) {
-		
-		if (is_string($string)) {
-			$ar = explode(",",$string);
-			$ar = array_map('trim', $ar); // trim blank spaces
-			$ar = array_map('elgg_strtolower', $ar); // make lower case : [Marcus Povey 20090605 - Using mb wrapper function using UTF8 safe function where available]
-			$ar = array_filter($ar, 'is_not_null'); // Remove null values
-			return $ar;
+	return false;
+}
+
+/**
+ * Returns a viewable list of entities based on the given search criteria.
+ *
+ * @see elgg_view_entity_list
+ *
+ * @param array $meta_array Array of 'name' => 'value' pairs
+ * @param string $entity_type The type of entity to look for, eg 'site' or 'object'
+ * @param string $entity_subtype The subtype of the entity.
+ * @param int $limit
+ * @param int $offset
+ * @param string $order_by Optional ordering.
+ * @param true|false $fullview Whether or not to display the full view (default: true)
+ * @param true|false $viewtypetoggle Whether or not to allow users to toggle to the gallery view. Default: true
+ * @param true|false $pagination Display pagination? Default: true
+ * @return string List of ElggEntities suitable for display
+ */
+function list_entities_from_metadata_multi($meta_array, $entity_type = "", $entity_subtype = "", $owner_guid = 0, $limit = 10, $fullview = true, $viewtypetoggle = true, $pagination = true) {
+	$offset = (int) get_input('offset');
+	$limit = (int) $limit;
+	$count = get_entities_from_metadata_multi($meta_array, $entity_type, $entity_subtype, $owner_guid, $limit, $offset, "", $site_guid, true);
+	$entities = get_entities_from_metadata_multi($meta_array, $entity_type, $entity_subtype, $owner_guid, $limit, $offset, "", $site_guid, false);
+
+	return elgg_view_entity_list($entities, $count, $offset, $limit, $fullview, $viewtypetoggle, $pagination);
+}
+
+/**
+ * Clear all the metadata for a given entity, assuming you have access to that metadata.
+ *
+ * @param int $guid
+ */
+function clear_metadata($entity_guid) {
+	global $CONFIG;
+
+	$entity_guid = (int)$entity_guid;
+	if ($entity = get_entity($entity_guid)) {
+		if ($entity->canEdit()) {
+			return delete_data("DELETE from {$CONFIG->dbprefix}metadata where entity_guid={$entity_guid}");
 		}
-		return false;
-		
 	}
-	
-	/**
-	 * Takes a metadata array (which has all kinds of properties) and turns it into a simple array of strings 
-	 *
-	 * @param array $array Metadata array
-	 * @return array Array of strings
-	 */
-	function metadata_array_to_values($array) {
-		
-		$valuearray = array();
-		
-		if (is_array($array)) {
-			foreach($array as $element) {
-				$valuearray[] = $element->value;
-			}
+	return false;
+}
+
+/**
+ * Clear all annotations belonging to a given owner_guid
+ *
+ * @param int $owner_guid The owner
+ */
+function clear_metadata_by_owner($owner_guid) {
+	global $CONFIG;
+
+	$owner_guid = (int)$owner_guid;
+
+	$metas = get_data("SELECT id from {$CONFIG->dbprefix}metadata WHERE owner_guid=$owner_guid");
+	$deleted = 0;
+
+	foreach ($metas as $id) {
+		// Is this the best way?
+		if (delete_metadata($id->id)) {
+			$deleted++;
 		}
-		
-		return $valuearray;
-		
 	}
-	
-	/**
-	 * Get the URL for this item of metadata, by default this links to the export handler in the current view.
-	 *
-	 * @param int $id
-	 */
-	function get_metadata_url($id)
-	{
-		$id = (int)$id;
-		
-		if ($extender = get_metadata($id)) {
-			return get_extender_url($extender);	
-		} 
-		return false;
+
+	return $deleted;
+}
+
+/**
+ * Handler called by trigger_plugin_hook on the "export" event.
+ */
+function export_metadata_plugin_hook($hook, $entity_type, $returnvalue, $params) {
+	// Sanity check values
+	if ((!is_array($params)) && (!isset($params['guid']))) {
+		throw new InvalidParameterException(elgg_echo('InvalidParameterException:GUIDNotForExport'));
 	}
-	
-	/**
-	 * Mark entities with a particular type and subtype as having access permissions
-	 * that can be changed independently from their parent entity
-	 *
-	 * @param string $type The type - object, user, etc
-	 * @param string $subtype The subtype; all subtypes by default
-	 */
-	function register_metadata_as_independent($type, $subtype = '*') {
-		global $CONFIG;
-		if (!isset($CONFIG->independents)) $CONFIG->independents = array();
-		$CONFIG->independents[$type][$subtype] = true;
+
+	if (!is_array($returnvalue)) {
+		throw new InvalidParameterException(elgg_echo('InvalidParameterException:NonArrayReturnValue'));
 	}
-	
-	/**
-	 * Determines whether entities of a given type and subtype should not change
-	 * their metadata in line with their parent entity 
-	 *
-	 * @param string $type The type - object, user, etc
-	 * @param string $subtype The entity subtype
-	 * @return true|false
-	 */
-	function is_metadata_independent($type, $subtype) {
-		global $CONFIG;
-		if (empty($CONFIG->independents)) return false;
-		if (!empty($CONFIG->independents[$type][$subtype])
-			|| !empty($CONFIG->independents[$type]['*'])) return true;
+
+	$guid = (int)$params['guid'];
+	$name = $params['name'];
+
+	$result = get_metadata_for_entity($guid);
+
+	if ($result) {
+		foreach ($result as $r) {
+			$returnvalue[] = $r->export();
+		}
+	}
+
+	return $returnvalue;
+}
+
+/**
+ * Takes in a comma-separated string and returns an array of tags which have been trimmed and set to lower case
+ *
+ * @param string $string Comma-separated tag string
+ * @return array|false An array of strings, or false on failure
+ */
+function string_to_tag_array($string) {
+	if (is_string($string)) {
+		$ar = explode(",",$string);
+		$ar = array_map('trim', $ar); // trim blank spaces
+		$ar = array_map('elgg_strtolower', $ar); // make lower case : [Marcus Povey 20090605 - Using mb wrapper function using UTF8 safe function where available]
+		$ar = array_filter($ar, 'is_not_null'); // Remove null values
+		return $ar;
+	}
+	return false;
+
+}
+
+/**
+ * Takes a metadata array (which has all kinds of properties) and turns it into a simple array of strings
+ *
+ * @param array $array Metadata array
+ * @return array Array of strings
+ */
+function metadata_array_to_values($array) {
+	$valuearray = array();
+
+	if (is_array($array)) {
+		foreach($array as $element) {
+			$valuearray[] = $element->value;
+		}
+	}
+
+	return $valuearray;
+}
+
+/**
+ * Get the URL for this item of metadata, by default this links to the export handler in the current view.
+ *
+ * @param int $id
+ */
+function get_metadata_url($id) {
+	$id = (int)$id;
+
+	if ($extender = get_metadata($id)) {
+		return get_extender_url($extender);
+	}
+	return false;
+}
+
+/**
+ * Mark entities with a particular type and subtype as having access permissions
+ * that can be changed independently from their parent entity
+ *
+ * @param string $type The type - object, user, etc
+ * @param string $subtype The subtype; all subtypes by default
+ */
+function register_metadata_as_independent($type, $subtype = '*') {
+	global $CONFIG;
+	if (!isset($CONFIG->independents)) {
+		$CONFIG->independents = array();
+	}
+	$CONFIG->independents[$type][$subtype] = true;
+}
+
+/**
+ * Determines whether entities of a given type and subtype should not change
+ * their metadata in line with their parent entity
+ *
+ * @param string $type The type - object, user, etc
+ * @param string $subtype The entity subtype
+ * @return true|false
+ */
+function is_metadata_independent($type, $subtype) {
+	global $CONFIG;
+	if (empty($CONFIG->independents)) {
 		return false;
 	}
-	
-	/**
-	 * When an entity is updated, resets the access ID on all of its child metadata
-	 *
-	 * @param string $event The name of the event
-	 * @param string $object_type The type of object
-	 * @param ElggEntity $object The entity itself
-	 */
-	function metadata_update($event, $object_type, $object) {
-		if ($object instanceof ElggEntity) {
-			if (!is_metadata_independent($object->getType(), $object->getSubtype())) {
-				global $CONFIG;
-				$access_id = (int) $object->access_id;
-				$guid = (int) $object->getGUID();
-				update_data("update {$CONFIG->dbprefix}metadata set access_id = {$access_id} where entity_guid = {$guid}");
-			}
-		}	
-		return true;	
+	if (!empty($CONFIG->independents[$type][$subtype])
+		|| !empty($CONFIG->independents[$type]['*'])) {
+			return true;
+		}
+	return false;
+}
+
+/**
+ * When an entity is updated, resets the access ID on all of its child metadata
+ *
+ * @param string $event The name of the event
+ * @param string $object_type The type of object
+ * @param ElggEntity $object The entity itself
+ */
+function metadata_update($event, $object_type, $object) {
+	if ($object instanceof ElggEntity) {
+		if (!is_metadata_independent($object->getType(), $object->getSubtype())) {
+			global $CONFIG;
+			$access_id = (int) $object->access_id;
+			$guid = (int) $object->getGUID();
+			update_data("update {$CONFIG->dbprefix}metadata set access_id = {$access_id} where entity_guid = {$guid}");
+		}
 	}
-	
-	/**
-	 * Register a metadata url handler.
-	 *
-	 * @param string $function_name The function.
-	 * @param string $extender_name The name, default 'all'.
-	 */
-	function register_metadata_url_handler($function_name, $extender_name = "all") {
-		return register_extender_url_handler($function_name, 'metadata', $extender_name);
-	}
-		
-	/** Register the hook */
-	register_plugin_hook("export", "all", "export_metadata_plugin_hook", 2);
-	/** Call a function whenever an entity is updated **/
-	register_elgg_event_handler('update','all','metadata_update');
-	
-?>
+	return true;
+}
+
+/**
+ * Register a metadata url handler.
+ *
+ * @param string $function_name The function.
+ * @param string $extender_name The name, default 'all'.
+ */
+function register_metadata_url_handler($function_name, $extender_name = "all") {
+	return register_extender_url_handler($function_name, 'metadata', $extender_name);
+}
+
+/** Register the hook */
+register_plugin_hook("export", "all", "export_metadata_plugin_hook", 2);
+/** Call a function whenever an entity is updated **/
+register_elgg_event_handler('update','all','metadata_update');
\ No newline at end of file