40 lines
684 B
Go
40 lines
684 B
Go
package levelmu
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import (
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"sync"
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)
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type LevelMutex struct {
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mus []sync.Mutex
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// Protected by the very last mutex.
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lastLevel int
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}
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func (lm *LevelMutex) Init(levels int) {
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if lm.mus != nil {
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panic("level mutex already initialized")
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}
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lm.mus = make([]sync.Mutex, levels)
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}
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func (lm *LevelMutex) Lock() {
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lm.LevelLock(0)
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}
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func (lm *LevelMutex) Unlock() {
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stopLevel := lm.lastLevel
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for i := len(lm.mus) - 1; i >= stopLevel; i-- {
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lm.mus[i].Unlock()
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}
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}
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func (lm *LevelMutex) LevelLock(level int) {
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if level >= len(lm.mus) {
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panic("lock level exceeds configured level count")
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}
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for l := level; l < len(lm.mus); l++ {
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lm.mus[l].Lock()
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}
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lm.lastLevel = level
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}
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