Add a flag to make the connection automatically emit the source object.

Mainly used to improve the connection dialog.

Author: Rindbee

core/object/object.cpp

@@ -1177,6 +1177,7 @@ Error Object::emit_signalp(const StringName &p_name, const Variant **p_args, int
 	OBJ_DEBUG_LOCK
 
 	Error err = OK;
+	Variant appended_self;
 
 	for (uint32_t i = 0; i < slot_count; ++i) {
 		const Callable &callable = slot_callables[i];
@@ -1190,6 +1191,18 @@ Error Object::emit_signalp(const StringName &p_name, const Variant **p_args, int
 		const Variant **args = p_args;
 		int argc = p_argcount;
 
+		if (flags & CONNECT_APPEND_SOURCE_OBJECT) {
+			argc += 1;
+			args = (const Variant **)alloca(sizeof(Variant *) * argc);
+			for (int j = 0; j < p_argcount; j++) {
+				args[j] = (const Variant *)p_args[j];
+			}
+			if (unlikely(appended_self.get_type() == Variant::NIL)) {
+				appended_self = this;
+			}
+			args[p_argcount] = &appended_self;
+		}
+
 		if (flags & CONNECT_DEFERRED) {
 			MessageQueue::get_singleton()->push_callablep(callable, args, argc, true);
 		} else {
@@ -1806,6 +1819,7 @@ void Object::_bind_methods() {
 	BIND_ENUM_CONSTANT(CONNECT_PERSIST);
 	BIND_ENUM_CONSTANT(CONNECT_ONE_SHOT);
 	BIND_ENUM_CONSTANT(CONNECT_REFERENCE_COUNTED);
+	BIND_ENUM_CONSTANT(CONNECT_APPEND_SOURCE_OBJECT);
 }
 
 void Object::set_deferred(const StringName &p_property, const Variant &p_value) {