genbindings: centralize AllowSignal/AllowMethod exceptions, block metacast signal

cmd/genbindings/clang2il.go

@@ -442,22 +442,18 @@ nextMethod:
 				return CppClass{}, err
 			}
 
-			for _, p := range mm.Parameters {
-				if strings.HasSuffix(p.ParameterType, "Private") {
-					log.Printf("Skipping method %q taking Private type", mm.MethodName)
+			mm.IsSignal = isSignal && !mm.IsStatic && AllowSignal(mm)
+
+			// Once all processing is complete, pass to exceptions for final decision
+
+			if err := AllowMethod(mm); err != nil {
+				if errors.Is(err, ErrTooComplex) {
+					log.Printf("Skipping method %q with complex type", mm.MethodName)
 					continue nextMethod
 				}
-			}
-			if strings.HasSuffix(mm.ReturnType.ParameterType, "Private") {
-				log.Printf("Skipping method %q returning Private type", mm.MethodName)
-				continue nextMethod
-			}
 
-			mm.IsSignal = isSignal && !mm.IsStatic && mm.MethodName != `metaObject`
-
-			if mm.IsReceiverMethod() {
-				log.Printf("Skipping method %q using non-projectable receiver pattern parameters", mm.MethodName)
-				continue nextMethod
+				// Real error
+				return CppClass{}, err
 			}
 
 			ret.Methods = append(ret.Methods, mm)

cmd/genbindings/exceptions.go

@@ -103,6 +103,35 @@ func AllowClass(className string) bool {
 	return true
 }
 
+func AllowSignal(mm CppMethod) bool {
+	switch mm.MethodName {
+	case `metaObject`, `qt_metacast`:
+		return false
+	default:
+		return true
+	}
+}
+
+func AllowMethod(mm CppMethod) error {
+
+	for _, p := range mm.Parameters {
+		if strings.HasSuffix(p.ParameterType, "Private") {
+			return ErrTooComplex // Skip private type
+		}
+	}
+	if strings.HasSuffix(mm.ReturnType.ParameterType, "Private") {
+		return ErrTooComplex // Skip private type
+	}
+
+	if mm.IsReceiverMethod() {
+		// Non-projectable receiver pattern parameters
+		return ErrTooComplex
+	}
+
+	return nil // OK, allow
+
+}
+
 func CheckComplexity(p CppParameter, isReturnType bool) error {
 
 	if p.QMapOf() {