| // 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. |
| |
| // +build !purego |
| |
| package cmp |
| |
| import ( |
| "reflect" |
| "unsafe" |
| ) |
| |
| const supportExporters = true |
| |
| // 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 |
| } |