39 lines
1.4 KiB
Go
39 lines
1.4 KiB
Go
// Copyright (c) 2014 Arista Networks, Inc.
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// Use of this source code is governed by the Apache License 2.0
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// that can be found in the COPYING file.
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// Package areflect provides utilities to help with reflection.
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package areflect
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import (
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"reflect"
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"unsafe"
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)
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// ForceExport returns a new reflect.Value that is identical to the one passed
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// in argument except that it's considered as an exported symbol even if in
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// reality it isn't.
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//
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// The `reflect' package intentionally makes it impossible to access the value
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// of an unexported attribute. The implementation of reflect.DeepEqual() cheats
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// as it bypasses this check. Unfortunately, we can't use the same cheat, which
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// prevents us from re-implementing DeepEqual properly or implementing some other
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// reflection-based tools. So this is our cheat on top of theirs. It makes
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// the given reflect.Value appear as if it was exported.
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//
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// This function requires go1.6 or newer.
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func ForceExport(v reflect.Value) reflect.Value {
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// constants from reflect/value.go
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const flagStickyRO uintptr = 1 << 5
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const flagEmbedRO uintptr = 1 << 6 // new in go1.6 (was flagIndir before)
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const flagRO uintptr = flagStickyRO | flagEmbedRO
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ptr := unsafe.Pointer(&v)
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rv := (*struct {
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typ unsafe.Pointer // a *reflect.rtype (reflect.Type)
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ptr unsafe.Pointer // The value wrapped by this reflect.Value
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flag uintptr
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})(ptr)
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rv.flag &= ^flagRO // Unset the flag so this value appears to be exported.
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return v
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}
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