mirror of https://github.com/docker/cli.git
32 lines
1.2 KiB
Go
32 lines
1.2 KiB
Go
// Copyright 2017, The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package cmp
|
|
|
|
import (
|
|
"reflect"
|
|
"unsafe"
|
|
)
|
|
|
|
// retrieveUnexportedField uses unsafe to forcibly retrieve any field from
|
|
// a struct such that the value has read-write permissions.
|
|
//
|
|
// The parent struct, v, must be addressable, while f must be a StructField
|
|
// describing the field to retrieve. If addr is false,
|
|
// then the returned value will be shallowed copied to be non-addressable.
|
|
func retrieveUnexportedField(v reflect.Value, f reflect.StructField, addr bool) reflect.Value {
|
|
ve := reflect.NewAt(f.Type, unsafe.Pointer(uintptr(unsafe.Pointer(v.UnsafeAddr()))+f.Offset)).Elem()
|
|
if !addr {
|
|
// A field is addressable if and only if the struct is addressable.
|
|
// If the original parent value was not addressable, shallow copy the
|
|
// value to make it non-addressable to avoid leaking an implementation
|
|
// detail of how forcibly exporting a field works.
|
|
if ve.Kind() == reflect.Interface && ve.IsNil() {
|
|
return reflect.Zero(f.Type)
|
|
}
|
|
return reflect.ValueOf(ve.Interface()).Convert(f.Type)
|
|
}
|
|
return ve
|
|
}
|