80 строки
1.8 KiB
Go
80 строки
1.8 KiB
Go
package common
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import (
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"sync"
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"github.com/Azure/azure-container-networking/log"
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)
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// NamedLock holds a mutex and a map of locks. Mutex is used to
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// get exclusive lock on the map while initializing the lock in the
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// map.
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type NamedLock struct {
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mutex sync.Mutex
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lockMap map[string]*refCountedLock
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}
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// refCountedLock holds the lock and ref count for it
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type refCountedLock struct {
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mutex sync.RWMutex
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refCount int
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}
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// InitNamedLock initializes the named lock struct
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func InitNamedLock() *NamedLock {
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return &NamedLock{
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mutex: sync.Mutex{},
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lockMap: make(map[string]*refCountedLock),
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}
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}
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// LockAcquire acquires the lock with specified name
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func (namedLock *NamedLock) LockAcquire(lockName string) {
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namedLock.mutex.Lock()
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_, ok := namedLock.lockMap[lockName]
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if !ok {
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namedLock.lockMap[lockName] = &refCountedLock{refCount: 0}
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}
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namedLock.lockMap[lockName].AddRef()
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namedLock.mutex.Unlock()
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namedLock.lockMap[lockName].Lock()
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}
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// LockRelease releases the lock with specified name
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func (namedLock *NamedLock) LockRelease(lockName string) {
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namedLock.mutex.Lock()
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defer namedLock.mutex.Unlock()
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lock, ok := namedLock.lockMap[lockName]
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if ok {
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lock.Unlock()
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lock.RemoveRef()
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if lock.refCount == 0 {
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delete(namedLock.lockMap, lockName)
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}
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} else {
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log.Printf("[Azure CNS] Attempt to unlock: %s without acquiring the lock", lockName)
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}
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}
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// AddRef increments the ref count on the lock
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func (refCountedLock *refCountedLock) AddRef() {
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refCountedLock.refCount++
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}
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// RemoveRef decrements the ref count on the lock
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func (refCountedLock *refCountedLock) RemoveRef() {
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refCountedLock.refCount--
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}
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// Lock locks the named lock
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func (refCountedLock *refCountedLock) Lock() {
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refCountedLock.mutex.Lock()
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}
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// Unlock unlocks the named lock
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func (refCountedLock *refCountedLock) Unlock() {
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refCountedLock.mutex.Unlock()
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}
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