[[ Script ]] Add ability to query a handler value bound to an instance

runrevmark · runrevmark · commit ac5d9200adf7 · 2016-09-14T19:30:40.000+01:00
This patch adds a QueryHandlerOfInstance API which allows creation
of a handler-ref which will invoke a specified handler within a given
instance.
diff --git a/libscript/include/libscript/script.h b/libscript/include/libscript/script.h
@@ -251,6 +251,9 @@ bool MCScriptCallHandlerOfInstance(MCScriptInstanceRef instance, MCNameRef handl
 // Call a handler of an instance if found, it doesn't throw an error if not.
 bool MCScriptCallHandlerOfInstanceIfFound(MCScriptInstanceRef instance, MCNameRef handler, MCValueRef *arguments, uindex_t argument_count, MCValueRef& r_value);
 
+// Create a handler-ref for the given handler in the instance.
+bool MCScriptCopyHandlerOfInstance(MCScriptInstanceRef instance, MCNameRef handler, /* copy */ MCHandlerRef& r_handler);
+
 ////////////////////////////////////////////////////////////////////////////////
 
 enum MCScriptBytecodeParameterType
diff --git a/libscript/src/script-instance.cpp b/libscript/src/script-instance.cpp
@@ -786,8 +786,7 @@ bool MCScriptCallHandlerOfInstance(MCScriptInstanceRef self, MCNameRef p_handler
 bool MCScriptCallHandlerOfInstanceIfFound(MCScriptInstanceRef self, MCNameRef p_handler, MCValueRef *p_arguments, uindex_t p_argument_count, MCValueRef& r_value)
 {
     __MCScriptValidateObjectAndKind__(self, kMCScriptObjectKindInstance);
-    
-    // Lookup the definition (throws if not found).
+	
     MCScriptHandlerDefinition *t_definition;
     if (!MCScriptLookupHandlerDefinitionInModule(self -> module, p_handler, t_definition))
     {
@@ -798,6 +797,20 @@ bool MCScriptCallHandlerOfInstanceIfFound(MCScriptInstanceRef self, MCNameRef p_
     return MCScriptCallHandlerOfInstanceDirect(self, t_definition, p_arguments, p_argument_count, r_value);
 }
 
+bool MCScriptCopyHandlerOfInstance(MCScriptInstanceRef self, MCNameRef p_name, MCHandlerRef& r_handler)
+{
+    __MCScriptValidateObjectAndKind__(self, kMCScriptObjectKindInstance);
+	
+    // Lookup the definition (throws if not found).
+    MCScriptHandlerDefinition *t_definition;
+    if (!MCScriptLookupHandlerDefinitionInModule(self -> module, p_name, t_definition))
+	{
+        return MCScriptThrowHandlerNotFoundError(self -> module, p_name);
+	}
+	
+	return MCScriptEvaluateHandlerOfInstanceInternal(self, t_definition, r_handler);
+}	
+
 ////////////////////////////////////////////////////////////////////////////////
 
 struct MCScriptFrameContext
