copy interface

Author: cheggaaa

deepcopy.go

@@ -11,6 +11,11 @@ import (
 	"time"
 )
 
+// Interface for delegating copy process to type
+type Interface interface {
+	DeepCopy() interface{}
+}
+
 // Iface is an alias to Copy; this exists for backwards compatibility reasons.
 func Iface(iface interface{}) interface{} {
 	return Copy(iface)
@@ -40,6 +45,14 @@ func Copy(src interface{}) interface{} {
 // copyRecursive does the actual copying of the interface. It currently has
 // limited support for what it can handle. Add as needed.
 func copyRecursive(original, cpy reflect.Value) {
+	// check for implement deepcopy.Interface
+	if original.CanInterface() {
+		if copier, ok := original.Interface().(Interface); ok {
+			cpy.Set(reflect.ValueOf(copier.DeepCopy()))
+			return
+		}
+	}
+
 	// handle according to original's Kind
 	switch original.Kind() {
 	case reflect.Ptr:

deepcopy_test.go

@@ -1082,3 +1082,29 @@ func TestIssue9(t *testing.T) {
 		}
 	}
 }
+
+type I struct {
+	A string
+}
+
+func (i *I) DeepCopy() interface{} {
+	return &I{A: "custom copy"}
+}
+
+type NestI struct {
+	I *I
+}
+
+func TestInterface(t *testing.T) {
+	i := &I{A: "A"}
+	copied := Copy(i).(*I)
+	if copied.A != "custom copy" {
+		t.Errorf("expected value %v, but it's %v", "custom copy", copied.A)
+	}
+	// check for nesting values
+	ni := &NestI{I: &I{A: "A"}}
+	copiedNest := Copy(ni).(*NestI)
+	if copiedNest.I.A != "custom copy" {
+		t.Errorf("expected value %v, but it's %v", "custom copy", copiedNest.I.A)
+	}
+}