[QRM] Prevent recursive scan if destination contains circular dependency.

qrm/type_stack.go

@@ -0,0 +1,40 @@
+package qrm
+
+import "reflect"
+
+type typeStack []*reflect.Type
+
+func newTypeStack() *typeStack {
+	stack := make(typeStack, 0, 20)
+	return &stack
+}
+
+func (s *typeStack) isEmpty() bool {
+	return len(*s) == 0
+}
+
+func (s *typeStack) push(t *reflect.Type) {
+	*s = append(*s, t)
+}
+
+func (s *typeStack) pop() bool {
+	if s.isEmpty() {
+		return false
+	}
+	*s = (*s)[:len(*s)-1]
+	return true
+}
+
+func (s *typeStack) contains(t *reflect.Type) bool {
+	if s.isEmpty() {
+		return false
+	}
+
+	for _, typ := range *s {
+		if *typ == *t {
+			return true
+		}
+	}
+
+	return false
+}