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36 lines
614 B
Go
36 lines
614 B
Go
// Copyright 2009 The Go Authors. All rights reserved.
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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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package utils
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import (
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"sync"
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"sync/atomic"
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)
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// Once is a fork of sync.Once to expose a Done() method.
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type Once struct {
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done uint32
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m sync.Mutex
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}
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func (o *Once) Do(f func()) {
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if atomic.LoadUint32(&o.done) == 0 {
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o.doSlow(f)
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}
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}
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func (o *Once) doSlow(f func()) {
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o.m.Lock()
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defer o.m.Unlock()
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if o.done == 0 {
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defer atomic.StoreUint32(&o.done, 1)
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f()
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}
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}
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func (o *Once) Done() bool {
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return atomic.LoadUint32(&o.done) == 1
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}
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