ENHANCEMENT: Added ClassInfo::is_subclass_of() for better performance

git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@83789 467b73ca-7a2a-4603-9d3b-597d59a354a9
silverstripe · Aug 5, 2009 · a72f7b2 · a72f7b2
1 parent a39ec17
commit a72f7b2
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Showing 2 changed files with 11 additions and 2 deletions.
diff --git a/core/ClassInfo.php b/core/ClassInfo.php
@@ -170,6 +170,15 @@ static function classImplements($className, $interfaceName) {
 	    global $_ALL_CLASSES;
 		return isset($_ALL_CLASSES['implementors'][$interfaceName][$className]);
 	}
+
+	/**
+	 * Returns true if $subclass is a subclass of $parentClass.
+	 * Identical to the PHP built-in function, but faster.
+	 */
+	static function is_subclass_of($subclass, $parentClass) {
+		global $_ALL_CLASSES;
+		return isset($_ALL_CLASSES['parents'][$subclass][$parentClass]);
+	}
 
 	/**
 	 * Get all classes contained in a file.

diff --git a/core/Object.php b/core/Object.php
@@ -391,7 +391,7 @@ public static function add_extension($class, $extension) {
 			user_error(sprintf('Object::add_extension() - Can\'t find extension class for "%s"', $extensionClass), E_USER_ERROR);
 		}
 
-		if(!is_subclass_of($extensionClass, 'Extension')) {
+		if(!ClassInfo::is_subclass_of($extensionClass, 'Extension')) {
 			user_error(sprintf('Object::add_extension() - Extension "%s" is not a subclass of Extension', $extensionClass), E_USER_ERROR);
 		}
 
@@ -407,7 +407,7 @@ public static function add_extension($class, $extension) {
 		self::add_static_var($class, 'extensions', array($extension));
 
 		// load statics now for DataObject classes
-		if(is_subclass_of($class, 'DataObject')) {
+		if(ClassInfo::is_subclass_of($class, 'DataObject')) {
 			DataObjectDecorator::load_extra_statics($class, $extensionClass);
 		}
 	}