ste/putListNeed.go

// Copyright © 2017 Microsoft <wastore@microsoft.com>
//
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//
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package ste

import "sync/atomic"

const (
	putListNotNeeded   = -1
	putListNeedUnknown = 0
	putListNeeded      = 1
)

// TODO: do we want to keep using atomic, just to be sure this is safe no matter how or where its used?
//    Or do we want to rely on the assumption, which is correct as at Jan 2018, that its only
//    used in the single-threaded chunk creation loop and in the epilogue. For now, we are erring on the side of safety.
func setPutListNeed(target *int32, value int32) {
	previous := atomic.SwapInt32(target, value)
	if previous != putListNeedUnknown && previous != value {
		panic("'put list' need cannot be set twice")
	}
}

func getPutListNeed(storage *int32) int32 {
	return atomic.LoadInt32(storage)
}