[feature/extension-manager] Make search backends loadable from extensions

Search backends are now required to be autoloadable. The database updater to
3.1 tries to guess the class name as phpbb_search_<oldname> which works for
the default backends we ship.

PHPBB3-10323

phpBB/includes/search/base.php

@@ -24,12 +24,12 @@ define('SEARCH_RESULT_IN_CACHE', 1);
 define('SEARCH_RESULT_INCOMPLETE', 2);
 
 /**
-* search_backend
+* phpbb_search_base
 * optional base class for search plugins providing simple caching based on ACM
 * and functions to retrieve ignore_words and synonyms
 * @package search
 */
-class search_backend
+class phpbb_search_base
 {
 	var $ignore_words = array();
 	var $match_synonym = array();

phpBB/includes/search/fulltext_mysql.php

@@ -16,17 +16,12 @@ if (!defined('IN_PHPBB'))
 	exit;
 }
 
-/**
-* @ignore
-*/
-include_once($phpbb_root_path . 'includes/search/search.' . $phpEx);
-
 /**
 * fulltext_mysql
 * Fulltext search for MySQL
 * @package search
 */
-class fulltext_mysql extends search_backend
+class phpbb_search_fulltext_mysql extends phpbb_search_base
 {
 	var $stats = array();
 	var $word_length = array();
@@ -36,7 +31,7 @@ class fulltext_mysql extends search_backend
 	var $pcre_properties = false;
 	var $mbstring_regex = false;
 
-	function fulltext_mysql(&$error)
+	public function __construct(&$error)
 	{
 		global $config;
 
@@ -57,6 +52,11 @@ class fulltext_mysql extends search_backend
 		$error = false;
 	}
 
+	function get_name()
+	{
+		return 'MySQL Fulltext';
+	}
+
 	/**
 	* Checks for correct MySQL version and stores min/max word length in the config
 	*/

phpBB/includes/search/fulltext_native.php

@@ -16,17 +16,12 @@ if (!defined('IN_PHPBB'))
 	exit;
 }
 
-/**
-* @ignore
-*/
-include_once($phpbb_root_path . 'includes/search/search.' . $phpEx);
-
 /**
 * fulltext_native
 * phpBB's own db driven fulltext search, version 2
 * @package search
 */
-class fulltext_native extends search_backend
+class phpbb_search_fulltext_native extends phpbb_search_base
 {
 	var $stats = array();
 	var $word_length = array();
@@ -41,10 +36,8 @@ class fulltext_native extends search_backend
 	* Initialises the fulltext_native search backend with min/max word length and makes sure the UTF-8 normalizer is loaded.
 	*
 	* @param	boolean|string	&$error	is passed by reference and should either be set to false on success or an error message on failure.
-	*
-	* @access	public
 	*/
-	function fulltext_native(&$error)
+	public function __construct(&$error)
 	{
 		global $phpbb_root_path, $phpEx, $config;
 
@@ -58,10 +51,14 @@ class fulltext_native extends search_backend
 			include($phpbb_root_path . 'includes/utf/utf_normalizer.' . $phpEx);
 		}
 
-
 		$error = false;
 	}
 
+	function get_name()
+	{
+		return 'phpBB Native Fulltext';
+	}
+
 	/**
 	* This function fills $this->search_query with the cleaned user search query.
 	*