2019-04-29 21:25:05 +00:00
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// Copyright 2019 The gVisor Authors.
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2018-10-03 20:50:58 +00:00
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//
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2019-02-01 01:47:24 +00:00
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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2018-10-03 20:50:58 +00:00
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// Package template doesn't exist. This file must be instantiated using the
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// go_template_instance rule in tools/go_generics/defs.bzl.
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package template
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import (
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"sync/atomic"
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"unsafe"
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)
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// Value is a required type parameter.
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type Value struct{}
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// An AtomicPtr is a pointer to a value of type Value that can be atomically
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// loaded and stored. The zero value of an AtomicPtr represents nil.
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//
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// Note that copying AtomicPtr by value performs a non-atomic read of the
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// stored pointer, which is unsafe if Store() can be called concurrently; in
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// this case, do `dst.Store(src.Load())` instead.
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2019-06-25 16:51:36 +00:00
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//
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// +stateify savable
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2018-10-03 20:50:58 +00:00
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type AtomicPtr struct {
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2019-06-25 16:51:36 +00:00
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ptr unsafe.Pointer `state:".(*Value)"`
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}
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func (p *AtomicPtr) savePtr() *Value {
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return p.Load()
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}
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func (p *AtomicPtr) loadPtr(v *Value) {
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p.Store(v)
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2018-10-03 20:50:58 +00:00
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}
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// Load returns the value set by the most recent Store. It returns nil if there
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// has been no previous call to Store.
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func (p *AtomicPtr) Load() *Value {
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return (*Value)(atomic.LoadPointer(&p.ptr))
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}
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// Store sets the value returned by Load to x.
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func (p *AtomicPtr) Store(x *Value) {
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atomic.StorePointer(&p.ptr, (unsafe.Pointer)(x))
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}
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