2016-01-29 20:53:56 +01:00
|
|
|
package copystructure
|
|
|
|
|
|
|
|
import (
|
|
|
|
"reflect"
|
2016-08-25 22:53:41 +02:00
|
|
|
"sync"
|
2016-01-29 20:53:56 +01:00
|
|
|
|
|
|
|
"github.com/mitchellh/reflectwalk"
|
|
|
|
)
|
|
|
|
|
|
|
|
// Copy returns a deep copy of v.
|
|
|
|
func Copy(v interface{}) (interface{}, error) {
|
2016-08-25 22:53:41 +02:00
|
|
|
return Config{}.Copy(v)
|
2016-01-29 20:53:56 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
// CopierFunc is a function that knows how to deep copy a specific type.
|
|
|
|
// Register these globally with the Copiers variable.
|
|
|
|
type CopierFunc func(interface{}) (interface{}, error)
|
|
|
|
|
|
|
|
// Copiers is a map of types that behave specially when they are copied.
|
|
|
|
// If a type is found in this map while deep copying, this function
|
|
|
|
// will be called to copy it instead of attempting to copy all fields.
|
|
|
|
//
|
|
|
|
// The key should be the type, obtained using: reflect.TypeOf(value with type).
|
|
|
|
//
|
|
|
|
// It is unsafe to write to this map after Copies have started. If you
|
|
|
|
// are writing to this map while also copying, wrap all modifications to
|
|
|
|
// this map as well as to Copy in a mutex.
|
|
|
|
var Copiers map[reflect.Type]CopierFunc = make(map[reflect.Type]CopierFunc)
|
|
|
|
|
2016-08-25 22:53:41 +02:00
|
|
|
type Config struct {
|
|
|
|
// Lock any types that are a sync.Locker and are not a mutex while copying.
|
|
|
|
// If there is an RLocker method, use that to get the sync.Locker.
|
|
|
|
Lock bool
|
|
|
|
|
|
|
|
// Copiers is a map of types associated with a CopierFunc. Use the global
|
|
|
|
// Copiers map if this is nil.
|
|
|
|
Copiers map[reflect.Type]CopierFunc
|
|
|
|
}
|
|
|
|
|
|
|
|
func (c Config) Copy(v interface{}) (interface{}, error) {
|
|
|
|
w := new(walker)
|
|
|
|
if c.Lock {
|
|
|
|
w.useLocks = true
|
|
|
|
}
|
|
|
|
|
|
|
|
if c.Copiers == nil {
|
|
|
|
c.Copiers = Copiers
|
|
|
|
}
|
|
|
|
|
|
|
|
err := reflectwalk.Walk(v, w)
|
|
|
|
if err != nil {
|
|
|
|
return nil, err
|
|
|
|
}
|
|
|
|
|
|
|
|
// Get the result. If the result is nil, then we want to turn it
|
|
|
|
// into a typed nil if we can.
|
|
|
|
result := w.Result
|
|
|
|
if result == nil {
|
|
|
|
val := reflect.ValueOf(v)
|
|
|
|
result = reflect.Indirect(reflect.New(val.Type())).Interface()
|
|
|
|
}
|
|
|
|
|
|
|
|
return result, nil
|
|
|
|
}
|
|
|
|
|
2016-01-29 20:53:56 +01:00
|
|
|
type walker struct {
|
|
|
|
Result interface{}
|
|
|
|
|
|
|
|
depth int
|
|
|
|
ignoreDepth int
|
|
|
|
vals []reflect.Value
|
|
|
|
cs []reflect.Value
|
|
|
|
ps []bool
|
2016-08-25 22:53:41 +02:00
|
|
|
|
|
|
|
// any locks we've taken, indexed by depth
|
|
|
|
locks []sync.Locker
|
|
|
|
// take locks while walking the structure
|
|
|
|
useLocks bool
|
2016-01-29 20:53:56 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) Enter(l reflectwalk.Location) error {
|
|
|
|
w.depth++
|
2016-08-25 22:53:41 +02:00
|
|
|
|
|
|
|
// ensure we have enough elements to index via w.depth
|
|
|
|
for w.depth >= len(w.locks) {
|
|
|
|
w.locks = append(w.locks, nil)
|
|
|
|
}
|
|
|
|
|
2016-01-29 20:53:56 +01:00
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) Exit(l reflectwalk.Location) error {
|
2016-08-25 22:53:41 +02:00
|
|
|
locker := w.locks[w.depth]
|
|
|
|
w.locks[w.depth] = nil
|
|
|
|
if locker != nil {
|
|
|
|
defer locker.Unlock()
|
|
|
|
}
|
|
|
|
|
2016-01-29 20:53:56 +01:00
|
|
|
w.depth--
|
|
|
|
if w.ignoreDepth > w.depth {
|
|
|
|
w.ignoreDepth = 0
|
|
|
|
}
|
|
|
|
|
|
|
|
if w.ignoring() {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
switch l {
|
|
|
|
case reflectwalk.Map:
|
|
|
|
fallthrough
|
|
|
|
case reflectwalk.Slice:
|
|
|
|
// Pop map off our container
|
|
|
|
w.cs = w.cs[:len(w.cs)-1]
|
|
|
|
case reflectwalk.MapValue:
|
|
|
|
// Pop off the key and value
|
|
|
|
mv := w.valPop()
|
|
|
|
mk := w.valPop()
|
|
|
|
m := w.cs[len(w.cs)-1]
|
2016-08-25 22:53:41 +02:00
|
|
|
|
|
|
|
// If mv is the zero value, SetMapIndex deletes the key form the map,
|
|
|
|
// or in this case never adds it. We need to create a properly typed
|
|
|
|
// zero value so that this key can be set.
|
|
|
|
if !mv.IsValid() {
|
|
|
|
mv = reflect.Zero(m.Type().Elem())
|
|
|
|
}
|
2016-01-29 20:53:56 +01:00
|
|
|
m.SetMapIndex(mk, mv)
|
|
|
|
case reflectwalk.SliceElem:
|
|
|
|
// Pop off the value and the index and set it on the slice
|
|
|
|
v := w.valPop()
|
2016-08-25 22:53:41 +02:00
|
|
|
if v.IsValid() {
|
|
|
|
i := w.valPop().Interface().(int)
|
|
|
|
s := w.cs[len(w.cs)-1]
|
|
|
|
se := s.Index(i)
|
|
|
|
if se.CanSet() {
|
|
|
|
se.Set(v)
|
|
|
|
}
|
|
|
|
}
|
2016-01-29 20:53:56 +01:00
|
|
|
case reflectwalk.Struct:
|
|
|
|
w.replacePointerMaybe()
|
|
|
|
|
|
|
|
// Remove the struct from the container stack
|
|
|
|
w.cs = w.cs[:len(w.cs)-1]
|
|
|
|
case reflectwalk.StructField:
|
|
|
|
// Pop off the value and the field
|
|
|
|
v := w.valPop()
|
|
|
|
f := w.valPop().Interface().(reflect.StructField)
|
|
|
|
if v.IsValid() {
|
|
|
|
s := w.cs[len(w.cs)-1]
|
|
|
|
sf := reflect.Indirect(s).FieldByName(f.Name)
|
2016-08-04 17:23:59 +02:00
|
|
|
if sf.CanSet() {
|
|
|
|
sf.Set(v)
|
|
|
|
}
|
2016-01-29 20:53:56 +01:00
|
|
|
}
|
|
|
|
case reflectwalk.WalkLoc:
|
|
|
|
// Clear out the slices for GC
|
|
|
|
w.cs = nil
|
|
|
|
w.vals = nil
|
|
|
|
}
|
|
|
|
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) Map(m reflect.Value) error {
|
|
|
|
if w.ignoring() {
|
|
|
|
return nil
|
|
|
|
}
|
2016-08-25 22:53:41 +02:00
|
|
|
w.lock(m)
|
2016-01-29 20:53:56 +01:00
|
|
|
|
|
|
|
// Create the map. If the map itself is nil, then just make a nil map
|
|
|
|
var newMap reflect.Value
|
|
|
|
if m.IsNil() {
|
2016-08-04 17:23:59 +02:00
|
|
|
newMap = reflect.Indirect(reflect.New(m.Type()))
|
2016-01-29 20:53:56 +01:00
|
|
|
} else {
|
2016-08-04 17:23:59 +02:00
|
|
|
newMap = reflect.MakeMap(m.Type())
|
2016-01-29 20:53:56 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
w.cs = append(w.cs, newMap)
|
|
|
|
w.valPush(newMap)
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) MapElem(m, k, v reflect.Value) error {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) PointerEnter(v bool) error {
|
|
|
|
if w.ignoring() {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
w.ps = append(w.ps, v)
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) PointerExit(bool) error {
|
|
|
|
if w.ignoring() {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
w.ps = w.ps[:len(w.ps)-1]
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) Primitive(v reflect.Value) error {
|
|
|
|
if w.ignoring() {
|
|
|
|
return nil
|
|
|
|
}
|
2016-08-25 22:53:41 +02:00
|
|
|
w.lock(v)
|
2016-01-29 20:53:56 +01:00
|
|
|
|
|
|
|
// IsValid verifies the v is non-zero and CanInterface verifies
|
|
|
|
// that we're allowed to read this value (unexported fields).
|
|
|
|
var newV reflect.Value
|
|
|
|
if v.IsValid() && v.CanInterface() {
|
|
|
|
newV = reflect.New(v.Type())
|
|
|
|
reflect.Indirect(newV).Set(v)
|
|
|
|
}
|
|
|
|
|
|
|
|
w.valPush(newV)
|
|
|
|
w.replacePointerMaybe()
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) Slice(s reflect.Value) error {
|
|
|
|
if w.ignoring() {
|
|
|
|
return nil
|
|
|
|
}
|
2016-08-25 22:53:41 +02:00
|
|
|
w.lock(s)
|
2016-01-29 20:53:56 +01:00
|
|
|
|
|
|
|
var newS reflect.Value
|
|
|
|
if s.IsNil() {
|
|
|
|
newS = reflect.Indirect(reflect.New(s.Type()))
|
|
|
|
} else {
|
|
|
|
newS = reflect.MakeSlice(s.Type(), s.Len(), s.Cap())
|
|
|
|
}
|
|
|
|
|
|
|
|
w.cs = append(w.cs, newS)
|
|
|
|
w.valPush(newS)
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) SliceElem(i int, elem reflect.Value) error {
|
|
|
|
if w.ignoring() {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
// We don't write the slice here because elem might still be
|
|
|
|
// arbitrarily complex. Just record the index and continue on.
|
|
|
|
w.valPush(reflect.ValueOf(i))
|
|
|
|
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) Struct(s reflect.Value) error {
|
|
|
|
if w.ignoring() {
|
|
|
|
return nil
|
|
|
|
}
|
2016-08-25 22:53:41 +02:00
|
|
|
w.lock(s)
|
2016-01-29 20:53:56 +01:00
|
|
|
|
|
|
|
var v reflect.Value
|
|
|
|
if c, ok := Copiers[s.Type()]; ok {
|
|
|
|
// We have a Copier for this struct, so we use that copier to
|
|
|
|
// get the copy, and we ignore anything deeper than this.
|
|
|
|
w.ignoreDepth = w.depth
|
|
|
|
|
|
|
|
dup, err := c(s.Interface())
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
|
|
|
|
v = reflect.ValueOf(dup)
|
|
|
|
} else {
|
|
|
|
// No copier, we copy ourselves and allow reflectwalk to guide
|
|
|
|
// us deeper into the structure for copying.
|
|
|
|
v = reflect.New(s.Type())
|
|
|
|
}
|
|
|
|
|
|
|
|
// Push the value onto the value stack for setting the struct field,
|
|
|
|
// and add the struct itself to the containers stack in case we walk
|
|
|
|
// deeper so that its own fields can be modified.
|
|
|
|
w.valPush(v)
|
|
|
|
w.cs = append(w.cs, v)
|
|
|
|
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) StructField(f reflect.StructField, v reflect.Value) error {
|
|
|
|
if w.ignoring() {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
// Push the field onto the stack, we'll handle it when we exit
|
|
|
|
// the struct field in Exit...
|
|
|
|
w.valPush(reflect.ValueOf(f))
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) ignoring() bool {
|
|
|
|
return w.ignoreDepth > 0 && w.depth >= w.ignoreDepth
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) pointerPeek() bool {
|
|
|
|
return w.ps[len(w.ps)-1]
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) valPop() reflect.Value {
|
|
|
|
result := w.vals[len(w.vals)-1]
|
|
|
|
w.vals = w.vals[:len(w.vals)-1]
|
|
|
|
|
|
|
|
// If we're out of values, that means we popped everything off. In
|
|
|
|
// this case, we reset the result so the next pushed value becomes
|
|
|
|
// the result.
|
|
|
|
if len(w.vals) == 0 {
|
|
|
|
w.Result = nil
|
|
|
|
}
|
|
|
|
|
|
|
|
return result
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) valPush(v reflect.Value) {
|
|
|
|
w.vals = append(w.vals, v)
|
|
|
|
|
|
|
|
// If we haven't set the result yet, then this is the result since
|
|
|
|
// it is the first (outermost) value we're seeing.
|
|
|
|
if w.Result == nil && v.IsValid() {
|
|
|
|
w.Result = v.Interface()
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *walker) replacePointerMaybe() {
|
|
|
|
// Determine the last pointer value. If it is NOT a pointer, then
|
|
|
|
// we need to push that onto the stack.
|
|
|
|
if !w.pointerPeek() {
|
|
|
|
w.valPush(reflect.Indirect(w.valPop()))
|
|
|
|
}
|
|
|
|
}
|
2016-08-25 22:53:41 +02:00
|
|
|
|
|
|
|
// if this value is a Locker, lock it and add it to the locks slice
|
|
|
|
func (w *walker) lock(v reflect.Value) {
|
|
|
|
if !w.useLocks {
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
if !v.IsValid() || !v.CanInterface() {
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
type rlocker interface {
|
|
|
|
RLocker() sync.Locker
|
|
|
|
}
|
|
|
|
|
|
|
|
var locker sync.Locker
|
|
|
|
|
|
|
|
// first check if we can get a locker from the value
|
|
|
|
switch l := v.Interface().(type) {
|
|
|
|
case rlocker:
|
|
|
|
// don't lock a mutex directly
|
|
|
|
if _, ok := l.(*sync.RWMutex); !ok {
|
|
|
|
locker = l.RLocker()
|
|
|
|
}
|
|
|
|
case sync.Locker:
|
|
|
|
locker = l
|
|
|
|
}
|
|
|
|
|
|
|
|
// the value itself isn't a locker, so check the method on a pointer too
|
|
|
|
if locker == nil && v.CanAddr() {
|
|
|
|
switch l := v.Addr().Interface().(type) {
|
|
|
|
case rlocker:
|
|
|
|
// don't lock a mutex directly
|
|
|
|
if _, ok := l.(*sync.RWMutex); !ok {
|
|
|
|
locker = l.RLocker()
|
|
|
|
}
|
|
|
|
case sync.Locker:
|
|
|
|
locker = l
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// still no callable locker
|
|
|
|
if locker == nil {
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
// don't lock a mutex directly
|
|
|
|
switch locker.(type) {
|
|
|
|
case *sync.Mutex, *sync.RWMutex:
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
locker.Lock()
|
|
|
|
w.locks[w.depth] = locker
|
|
|
|
}
|