mirror of https://github.com/k3s-io/k3s
61 lines
1.6 KiB
Go
61 lines
1.6 KiB
Go
/*
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Copyright 2015 The Kubernetes Authors All rights reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package util
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import (
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"sync"
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"sync/atomic"
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)
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// TODO(ArtfulCoder)
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// sync/atomic/Value was added in golang 1.4
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// Once support is dropped for go 1.3, this type must be deprecated in favor of sync/atomic/Value.
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// The functions are named Load/Store to match sync/atomic/Value function names.
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type AtomicValue struct {
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value interface{}
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valueMutex sync.RWMutex
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}
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func (at *AtomicValue) Store(val interface{}) {
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at.valueMutex.Lock()
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defer at.valueMutex.Unlock()
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at.value = val
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}
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func (at *AtomicValue) Load() interface{} {
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at.valueMutex.RLock()
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defer at.valueMutex.RUnlock()
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return at.value
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}
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// HighWaterMark is a thread-safe object for tracking the maximum value seen
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// for some quantity.
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type HighWaterMark int64
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// Check returns true iff 'current' is the highest value ever seen.
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func (hwm *HighWaterMark) Check(current int64) bool {
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for {
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old := atomic.LoadInt64((*int64)(hwm))
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if current <= old {
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return false
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}
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if atomic.CompareAndSwapInt64((*int64)(hwm), old, current) {
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return true
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}
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}
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}
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