mirror of
https://github.com/ceph/ceph-csi.git
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78 lines
1.5 KiB
Go
78 lines
1.5 KiB
Go
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/*
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Copyright 2019 ceph-csi authors.
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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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)
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/*
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IDLock is a per identifier lock with a use counter that retains a number of users of the lock.
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IDLocker is a map of IDLocks holding the IDLocks based on a passed in identifier.
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Typical usage (post creating an IDLocker) is to Lock/Unlock based on identifiers as per the API.
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*/
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type (
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IDLock struct {
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mtx sync.Mutex
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useCount int
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}
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IDLocker struct {
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lMutex sync.Mutex
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lMap map[string]*IDLock
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}
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)
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func NewIDLocker() *IDLocker {
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return &IDLocker{
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lMap: make(map[string]*IDLock),
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}
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}
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func (lkr *IDLocker) Lock(identifier string) *IDLock {
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var (
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lk *IDLock
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ok bool
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)
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newlk := new(IDLock)
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lkr.lMutex.Lock()
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if lk, ok = lkr.lMap[identifier]; !ok {
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lk = newlk
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lkr.lMap[identifier] = lk
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}
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lk.useCount++
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lkr.lMutex.Unlock()
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lk.mtx.Lock()
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return lk
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}
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func (lkr *IDLocker) Unlock(lk *IDLock, identifier string) {
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lk.mtx.Unlock()
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lkr.lMutex.Lock()
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lk.useCount--
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if lk.useCount == 0 {
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delete(lkr.lMap, identifier)
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}
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lkr.lMutex.Unlock()
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}
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