[feature/auto-loading] Added autoloader to common and ensured compatability

The autoloader is registered in install without caching, since caching is set
up during installation. This provides the same functionality, performance is
not a concern during installation anyway.

In common.php the autoloader is instantiated after the cache is initialised and
is started with the standard cache backend used for other cached values.

A few places in the code using class_exists had to be updated to explicitly
avoid autoloading, since they are used to check whether a file needs to be
included which does not (yet) follow the naming scheme the autoloader follows.

PHPBB3-9682

phpBB/common.php

@@ -188,6 +188,7 @@ if (!empty($load_extensions) && function_exists('dl'))
 }
 
 // Include files
+require($phpbb_root_path . 'includes/class_loader.' . $phpEx);
 require($phpbb_root_path . 'includes/acm/acm_' . $acm_type . '.' . $phpEx);
 require($phpbb_root_path . 'includes/cache.' . $phpEx);
 require($phpbb_root_path . 'includes/template.' . $phpEx);
@@ -211,6 +212,9 @@ $template	= new template();
 $cache		= new cache();
 $db			= new $sql_db();
 
+$class_loader = new phpbb_class_loader($phpbb_root_path, '.' . $phpEx, $cache);
+$class_loader->register();
+
 // Connect to DB
 $db->sql_connect($dbhost, $dbuser, $dbpasswd, $dbname, $dbport, false, defined('PHPBB_DB_NEW_LINK') ? PHPBB_DB_NEW_LINK : false);
 

phpBB/includes/auth/auth_db.php

@@ -69,7 +69,7 @@ function login_db(&$username, &$password)
 	if ($show_captcha)
 	{
 		// Visual Confirmation handling
-		if (!class_exists('phpbb_captcha_factory'))
+		if (!class_exists('phpbb_captcha_factory', false))
 		{
 			global $phpbb_root_path, $phpEx;
 			include ($phpbb_root_path . 'includes/captcha/captcha_factory.' . $phpEx);

phpBB/includes/captcha/plugins/phpbb_captcha_gd_plugin.php

@@ -19,7 +19,7 @@ if (!defined('IN_PHPBB'))
 /**
 * Placeholder for autoload
 */
-if (!class_exists('phpbb_default_captcha'))
+if (!class_exists('phpbb_default_captcha', false))
 {
 	include($phpbb_root_path . 'includes/captcha/plugins/captcha_abstract.' . $phpEx);
 }

phpBB/includes/captcha/plugins/phpbb_captcha_gd_wave_plugin.php

@@ -19,7 +19,7 @@ if (!defined('IN_PHPBB'))
 /**
 * Placeholder for autoload
 */
-if (!class_exists('phpbb_default_captcha'))
+if (!class_exists('phpbb_default_captcha', false))
 {
 	include($phpbb_root_path . 'includes/captcha/plugins/captcha_abstract.' . $phpEx);
 }

phpBB/includes/captcha/plugins/phpbb_captcha_nogd_plugin.php

@@ -19,7 +19,7 @@ if (!defined('IN_PHPBB'))
 /**
 * Placeholder for autoload
 */
-if (!class_exists('phpbb_default_captcha'))
+if (!class_exists('phpbb_default_captcha', false))
 {
 	include($phpbb_root_path . 'includes/captcha/plugins/captcha_abstract.' . $phpEx);
 }

phpBB/includes/captcha/plugins/phpbb_captcha_qa_plugin.php

@@ -113,7 +113,7 @@ class phpbb_captcha_qa
 	{
 		global $db, $phpbb_root_path, $phpEx;
 
-		if (!class_exists('phpbb_db_tools'))
+		if (!class_exists('phpbb_db_tools', false))
 		{
 			include("$phpbb_root_path/includes/db/db_tools.$phpEx");
 		}

phpBB/includes/captcha/plugins/phpbb_recaptcha_plugin.php

@@ -16,7 +16,7 @@ if (!defined('IN_PHPBB'))
 	exit;
 }
 
-if (!class_exists('phpbb_default_captcha'))
+if (!class_exists('phpbb_default_captcha', false))
 {
 	// we need the classic captcha code for tracking solutions and attempts
 	include($phpbb_root_path . 'includes/captcha/plugins/captcha_abstract.' . $phpEx);

phpBB/includes/functions.php

@@ -2840,7 +2840,7 @@ function login_box($redirect = '', $l_explain = '', $l_success = '', $admin = fa
 {
 	global $db, $user, $template, $auth, $phpEx, $phpbb_root_path, $config;
 
-	if (!class_exists('phpbb_captcha_factory'))
+	if (!class_exists('phpbb_captcha_factory', false))
 	{
 		include($phpbb_root_path . 'includes/captcha/captcha_factory.' . $phpEx);
 	}

phpBB/includes/session.php

@@ -983,7 +983,7 @@ class session
 			}
 
 			// only called from CRON; should be a safe workaround until the infrastructure gets going
-			if (!class_exists('phpbb_captcha_factory'))
+			if (!class_exists('phpbb_captcha_factory', false))
 			{
 				include($phpbb_root_path . "includes/captcha/captcha_factory." . $phpEx);
 			}

phpBB/install/index.php

@@ -152,6 +152,7 @@ else
 @ini_set('memory_limit', $mem_limit);
 
 // Include essential scripts
+require($phpbb_root_path . 'includes/class_loader.' . $phpEx);
 require($phpbb_root_path . 'includes/functions.' . $phpEx);
 
 if (file_exists($phpbb_root_path . 'includes/functions_content.' . $phpEx))
@@ -168,6 +169,9 @@ include($phpbb_root_path . 'includes/functions_admin.' . $phpEx);
 include($phpbb_root_path . 'includes/utf/utf_tools.' . $phpEx);
 require($phpbb_root_path . 'includes/functions_install.' . $phpEx);
 
+$class_loader = new phpbb_class_loader($phpbb_root_path, '.' . $phpEx);
+$class_loader->register();
+
 // Try and load an appropriate language if required
 $language = basename(request_var('language', ''));