126 lines
3.4 KiB
Go
126 lines
3.4 KiB
Go
// deepcopy makes deep copies of things. A standard copy will copy the
|
|
// pointers: deep copy copies the values pointed to. Unexported field
|
|
// values are not copied.
|
|
//
|
|
// Copyright (c)2014-2016, Joel Scoble (github.com/mohae), all rights reserved.
|
|
// License: MIT, for more details check the included LICENSE file.
|
|
package deepcopy
|
|
|
|
import (
|
|
"reflect"
|
|
"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)
|
|
}
|
|
|
|
// Copy creates a deep copy of whatever is passed to it and returns the copy
|
|
// in an interface{}. The returned value will need to be asserted to the
|
|
// correct type.
|
|
func Copy(src interface{}) interface{} {
|
|
if src == nil {
|
|
return nil
|
|
}
|
|
|
|
// Make the interface a reflect.Value
|
|
original := reflect.ValueOf(src)
|
|
|
|
// Make a copy of the same type as the original.
|
|
cpy := reflect.New(original.Type()).Elem()
|
|
|
|
// Recursively copy the original.
|
|
copyRecursive(original, cpy)
|
|
|
|
// Return the copy as an interface.
|
|
return cpy.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:
|
|
// Get the actual value being pointed to.
|
|
originalValue := original.Elem()
|
|
|
|
// if it isn't valid, return.
|
|
if !originalValue.IsValid() {
|
|
return
|
|
}
|
|
cpy.Set(reflect.New(originalValue.Type()))
|
|
copyRecursive(originalValue, cpy.Elem())
|
|
|
|
case reflect.Interface:
|
|
// If this is a nil, don't do anything
|
|
if original.IsNil() {
|
|
return
|
|
}
|
|
// Get the value for the interface, not the pointer.
|
|
originalValue := original.Elem()
|
|
|
|
// Get the value by calling Elem().
|
|
copyValue := reflect.New(originalValue.Type()).Elem()
|
|
copyRecursive(originalValue, copyValue)
|
|
cpy.Set(copyValue)
|
|
|
|
case reflect.Struct:
|
|
t, ok := original.Interface().(time.Time)
|
|
if ok {
|
|
cpy.Set(reflect.ValueOf(t))
|
|
return
|
|
}
|
|
// Go through each field of the struct and copy it.
|
|
for i := 0; i < original.NumField(); i++ {
|
|
// The Type's StructField for a given field is checked to see if StructField.PkgPath
|
|
// is set to determine if the field is exported or not because CanSet() returns false
|
|
// for settable fields. I'm not sure why. -mohae
|
|
if original.Type().Field(i).PkgPath != "" {
|
|
continue
|
|
}
|
|
copyRecursive(original.Field(i), cpy.Field(i))
|
|
}
|
|
|
|
case reflect.Slice:
|
|
if original.IsNil() {
|
|
return
|
|
}
|
|
// Make a new slice and copy each element.
|
|
cpy.Set(reflect.MakeSlice(original.Type(), original.Len(), original.Cap()))
|
|
for i := 0; i < original.Len(); i++ {
|
|
copyRecursive(original.Index(i), cpy.Index(i))
|
|
}
|
|
|
|
case reflect.Map:
|
|
if original.IsNil() {
|
|
return
|
|
}
|
|
cpy.Set(reflect.MakeMap(original.Type()))
|
|
for _, key := range original.MapKeys() {
|
|
originalValue := original.MapIndex(key)
|
|
copyValue := reflect.New(originalValue.Type()).Elem()
|
|
copyRecursive(originalValue, copyValue)
|
|
copyKey := Copy(key.Interface())
|
|
cpy.SetMapIndex(reflect.ValueOf(copyKey), copyValue)
|
|
}
|
|
|
|
default:
|
|
cpy.Set(original)
|
|
}
|
|
}
|