249 lines
7.1 KiB
Go
249 lines
7.1 KiB
Go
/*
|
|
Copyright 2014 The Kubernetes Authors.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
package conversion
|
|
|
|
import (
|
|
"fmt"
|
|
"reflect"
|
|
)
|
|
|
|
// Cloner knows how to copy one type to another.
|
|
type Cloner struct {
|
|
// Map from the type to a function which can do the deep copy.
|
|
deepCopyFuncs map[reflect.Type]reflect.Value
|
|
generatedDeepCopyFuncs map[reflect.Type]func(in interface{}, out interface{}, c *Cloner) error
|
|
}
|
|
|
|
// NewCloner creates a new Cloner object.
|
|
func NewCloner() *Cloner {
|
|
c := &Cloner{
|
|
deepCopyFuncs: map[reflect.Type]reflect.Value{},
|
|
generatedDeepCopyFuncs: map[reflect.Type]func(in interface{}, out interface{}, c *Cloner) error{},
|
|
}
|
|
if err := c.RegisterDeepCopyFunc(byteSliceDeepCopy); err != nil {
|
|
// If one of the deep-copy functions is malformed, detect it immediately.
|
|
panic(err)
|
|
}
|
|
return c
|
|
}
|
|
|
|
// Prevent recursing into every byte...
|
|
func byteSliceDeepCopy(in *[]byte, out *[]byte, c *Cloner) error {
|
|
if *in != nil {
|
|
*out = make([]byte, len(*in))
|
|
copy(*out, *in)
|
|
} else {
|
|
*out = nil
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Verifies whether a deep-copy function has a correct signature.
|
|
func verifyDeepCopyFunctionSignature(ft reflect.Type) error {
|
|
if ft.Kind() != reflect.Func {
|
|
return fmt.Errorf("expected func, got: %v", ft)
|
|
}
|
|
if ft.NumIn() != 3 {
|
|
return fmt.Errorf("expected three 'in' params, got %v", ft)
|
|
}
|
|
if ft.NumOut() != 1 {
|
|
return fmt.Errorf("expected one 'out' param, got %v", ft)
|
|
}
|
|
if ft.In(0).Kind() != reflect.Ptr {
|
|
return fmt.Errorf("expected pointer arg for 'in' param 0, got: %v", ft)
|
|
}
|
|
if ft.In(1) != ft.In(0) {
|
|
return fmt.Errorf("expected 'in' param 0 the same as param 1, got: %v", ft)
|
|
}
|
|
var forClonerType Cloner
|
|
if expected := reflect.TypeOf(&forClonerType); ft.In(2) != expected {
|
|
return fmt.Errorf("expected '%v' arg for 'in' param 2, got: '%v'", expected, ft.In(2))
|
|
}
|
|
var forErrorType error
|
|
// This convolution is necessary, otherwise TypeOf picks up on the fact
|
|
// that forErrorType is nil
|
|
errorType := reflect.TypeOf(&forErrorType).Elem()
|
|
if ft.Out(0) != errorType {
|
|
return fmt.Errorf("expected error return, got: %v", ft)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// RegisterGeneratedDeepCopyFunc registers a copying func with the Cloner.
|
|
// deepCopyFunc must take three parameters: a type input, a pointer to a
|
|
// type output, and a pointer to Cloner. It should return an error.
|
|
//
|
|
// Example:
|
|
// c.RegisterGeneratedDeepCopyFunc(
|
|
// func(in Pod, out *Pod, c *Cloner) error {
|
|
// // deep copy logic...
|
|
// return nil
|
|
// })
|
|
func (c *Cloner) RegisterDeepCopyFunc(deepCopyFunc interface{}) error {
|
|
fv := reflect.ValueOf(deepCopyFunc)
|
|
ft := fv.Type()
|
|
if err := verifyDeepCopyFunctionSignature(ft); err != nil {
|
|
return err
|
|
}
|
|
c.deepCopyFuncs[ft.In(0)] = fv
|
|
return nil
|
|
}
|
|
|
|
// GeneratedDeepCopyFunc bundles an untyped generated deep-copy function of a type
|
|
// with a reflection type object used as a key to lookup the deep-copy function.
|
|
type GeneratedDeepCopyFunc struct {
|
|
Fn func(in interface{}, out interface{}, c *Cloner) error
|
|
InType reflect.Type
|
|
}
|
|
|
|
// Similar to RegisterDeepCopyFunc, but registers deep copy function that were
|
|
// automatically generated.
|
|
func (c *Cloner) RegisterGeneratedDeepCopyFunc(fn GeneratedDeepCopyFunc) error {
|
|
c.generatedDeepCopyFuncs[fn.InType] = fn.Fn
|
|
return nil
|
|
}
|
|
|
|
// DeepCopy will perform a deep copy of a given object.
|
|
func (c *Cloner) DeepCopy(in interface{}) (interface{}, error) {
|
|
// Can be invalid if we run DeepCopy(X) where X is a nil interface type.
|
|
// For example, we get an invalid value when someone tries to deep-copy
|
|
// a nil labels.Selector.
|
|
// This does not occur if X is nil and is a pointer to a concrete type.
|
|
if in == nil {
|
|
return nil, nil
|
|
}
|
|
inValue := reflect.ValueOf(in)
|
|
outValue, err := c.deepCopy(inValue)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return outValue.Interface(), nil
|
|
}
|
|
|
|
func (c *Cloner) deepCopy(src reflect.Value) (reflect.Value, error) {
|
|
inType := src.Type()
|
|
|
|
switch src.Kind() {
|
|
case reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
|
|
if src.IsNil() {
|
|
return src, nil
|
|
}
|
|
}
|
|
|
|
if fv, ok := c.deepCopyFuncs[inType]; ok {
|
|
return c.customDeepCopy(src, fv)
|
|
}
|
|
if fv, ok := c.generatedDeepCopyFuncs[inType]; ok {
|
|
var outValue reflect.Value
|
|
outValue = reflect.New(inType.Elem())
|
|
err := fv(src.Interface(), outValue.Interface(), c)
|
|
return outValue, err
|
|
}
|
|
return c.defaultDeepCopy(src)
|
|
}
|
|
|
|
func (c *Cloner) customDeepCopy(src, fv reflect.Value) (reflect.Value, error) {
|
|
outValue := reflect.New(src.Type().Elem())
|
|
args := []reflect.Value{src, outValue, reflect.ValueOf(c)}
|
|
result := fv.Call(args)[0].Interface()
|
|
// This convolution is necessary because nil interfaces won't convert
|
|
// to error.
|
|
if result == nil {
|
|
return outValue, nil
|
|
}
|
|
return outValue, result.(error)
|
|
}
|
|
|
|
func (c *Cloner) defaultDeepCopy(src reflect.Value) (reflect.Value, error) {
|
|
switch src.Kind() {
|
|
case reflect.Chan, reflect.Func, reflect.UnsafePointer, reflect.Uintptr:
|
|
return src, fmt.Errorf("cannot deep copy kind: %s", src.Kind())
|
|
case reflect.Array:
|
|
dst := reflect.New(src.Type())
|
|
for i := 0; i < src.Len(); i++ {
|
|
copyVal, err := c.deepCopy(src.Index(i))
|
|
if err != nil {
|
|
return src, err
|
|
}
|
|
dst.Elem().Index(i).Set(copyVal)
|
|
}
|
|
return dst.Elem(), nil
|
|
case reflect.Interface:
|
|
if src.IsNil() {
|
|
return src, nil
|
|
}
|
|
return c.deepCopy(src.Elem())
|
|
case reflect.Map:
|
|
if src.IsNil() {
|
|
return src, nil
|
|
}
|
|
dst := reflect.MakeMap(src.Type())
|
|
for _, k := range src.MapKeys() {
|
|
copyVal, err := c.deepCopy(src.MapIndex(k))
|
|
if err != nil {
|
|
return src, err
|
|
}
|
|
dst.SetMapIndex(k, copyVal)
|
|
}
|
|
return dst, nil
|
|
case reflect.Ptr:
|
|
if src.IsNil() {
|
|
return src, nil
|
|
}
|
|
dst := reflect.New(src.Type().Elem())
|
|
copyVal, err := c.deepCopy(src.Elem())
|
|
if err != nil {
|
|
return src, err
|
|
}
|
|
dst.Elem().Set(copyVal)
|
|
return dst, nil
|
|
case reflect.Slice:
|
|
if src.IsNil() {
|
|
return src, nil
|
|
}
|
|
dst := reflect.MakeSlice(src.Type(), 0, src.Len())
|
|
for i := 0; i < src.Len(); i++ {
|
|
copyVal, err := c.deepCopy(src.Index(i))
|
|
if err != nil {
|
|
return src, err
|
|
}
|
|
dst = reflect.Append(dst, copyVal)
|
|
}
|
|
return dst, nil
|
|
case reflect.Struct:
|
|
dst := reflect.New(src.Type())
|
|
for i := 0; i < src.NumField(); i++ {
|
|
if !dst.Elem().Field(i).CanSet() {
|
|
// Can't set private fields. At this point, the
|
|
// best we can do is a shallow copy. For
|
|
// example, time.Time is a value type with
|
|
// private members that can be shallow copied.
|
|
return src, nil
|
|
}
|
|
copyVal, err := c.deepCopy(src.Field(i))
|
|
if err != nil {
|
|
return src, err
|
|
}
|
|
dst.Elem().Field(i).Set(copyVal)
|
|
}
|
|
return dst.Elem(), nil
|
|
|
|
default:
|
|
// Value types like numbers, booleans, and strings.
|
|
return src, nil
|
|
}
|
|
}
|