79 lines
1.0 KiB
Go
79 lines
1.0 KiB
Go
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package sync
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import (
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"sync"
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)
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/*
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ChannelRWMutexV1
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使用四把锁
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*/
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type ChannelRWMutexV1 struct {
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mu sync.Mutex // 互斥锁
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rm sync.Mutex // 读等待锁
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wm sync.Mutex // 写等待锁
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cmu sync.Mutex // 计数锁
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rn int // 读等待
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wn int // 写等待
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}
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func NewRWMutexV1() RWLocker {
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return &ChannelRWMutexV1{}
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}
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func (rw *ChannelRWMutexV1) RLock() {
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rw.cmu.Lock()
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if rw.wn > 0 {
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rw.cmu.Unlock()
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rw.wm.Lock()
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rw.wm.Unlock()
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} else {
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defer rw.cmu.Unlock()
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}
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rw.rn++
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if rw.rn == 1 {
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rw.wm.Lock()
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}
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}
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func (rw *ChannelRWMutexV1) RUnlock() {
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rw.cmu.Lock()
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defer rw.cmu.Unlock()
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rw.rn--
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if rw.rn == 0 {
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rw.wm.Unlock()
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}
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}
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func (rw *ChannelRWMutexV1) Lock() {
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rw.cmu.Lock()
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if rw.rn > 0 {
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rw.cmu.Unlock()
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rw.wm.Lock()
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rw.wm.Unlock()
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} else {
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defer rw.cmu.Unlock()
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}
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rw.wn++
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if rw.wn == 1 {
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rw.rm.Lock()
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}
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rw.mu.Lock()
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}
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func (rw *ChannelRWMutexV1) Unlock() {
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rw.cmu.Lock()
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defer rw.cmu.Unlock()
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rw.wn--
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if rw.wn == 0 {
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rw.rm.Unlock()
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}
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rw.mu.Unlock()
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}
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