68 lines
1.1 KiB
Go
68 lines
1.1 KiB
Go
package keyedmutex
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import (
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"container/list"
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"sync"
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)
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type KeyedMutex[K comparable] struct {
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mu *sync.Mutex
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waitList map[K]*list.List
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}
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func New[K comparable]() KeyedMutex[K] {
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return KeyedMutex[K]{
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mu: new(sync.Mutex),
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waitList: map[K]*list.List{},
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}
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}
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func (m KeyedMutex[K]) Lock(key K) {
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if ch := m.lock(key); ch != nil {
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<-ch
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}
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}
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func (m KeyedMutex[K]) lock(key K) chan struct{} {
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m.mu.Lock()
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defer m.mu.Unlock()
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if waitList, ok := m.waitList[key]; ok {
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ch := make(chan struct{})
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waitList.PushBack(ch)
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return ch
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}
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m.waitList[key] = list.New()
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return nil
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}
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func (m KeyedMutex[K]) TryLock(key K) bool {
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m.mu.Lock()
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defer m.mu.Unlock()
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if _, ok := m.waitList[key]; ok {
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return false
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}
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m.waitList[key] = list.New()
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return true
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}
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func (m KeyedMutex[K]) Unlock(key K) {
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m.mu.Lock()
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defer m.mu.Unlock()
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waitList, ok := m.waitList[key]
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if !ok {
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panic("unlock of unlocked mutex")
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}
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if waitList.Len() == 0 {
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delete(m.waitList, key)
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} else {
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ch := waitList.Remove(waitList.Front()).(chan struct{})
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ch <- struct{}{}
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}
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}
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