374ec482cd
don't republish thumbs that were published from previous channels
96 lines
1.8 KiB
Go
96 lines
1.8 KiB
Go
package ml
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import (
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"sync"
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)
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// MultipleLock is the main interface for multiLock based on key
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type MultipleLock interface {
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// Lock base on the key
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Lock(interface{})
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// RLock multiLock the rw for reading
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RLock(interface{})
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// Unlock the key
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Unlock(interface{})
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// RUnlock the the read multiLock
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RUnlock(interface{})
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}
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func NewMultipleLock() MultipleLock {
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return &multiLock{
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locks: make(map[interface{}]*itemLock),
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lkMux: sync.Mutex{},
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}
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}
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type itemLock struct {
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lk *sync.RWMutex
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cnt int64
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}
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// multiLock is an optimized locking system per locking key
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type multiLock struct {
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locks map[interface{}]*itemLock
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lkMux sync.Mutex // protects the locks
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}
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func (l *multiLock) Lock(itmID interface{}) {
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l.lkMux.Lock()
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itmLock, exists := l.locks[itmID]
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if !exists {
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itmLock = &itemLock{&sync.RWMutex{}, 0}
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l.locks[itmID] = itmLock
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}
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itmLock.cnt++
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l.lkMux.Unlock()
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itmLock.lk.Lock()
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}
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func (l *multiLock) RLock(itmID interface{}) {
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l.lkMux.Lock()
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itmLock, exists := l.locks[itmID]
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if !exists {
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itmLock = &itemLock{&sync.RWMutex{}, 0}
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l.locks[itmID] = itmLock
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}
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itmLock.cnt++
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l.lkMux.Unlock()
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itmLock.lk.RLock()
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}
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func (l *multiLock) Unlock(itmID interface{}) {
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l.lkMux.Lock()
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itmLock, exists := l.locks[itmID]
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if !exists {
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panic("sync Unlock of non existent lock!!")
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}
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itmLock.lk.Unlock()
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itmLock.cnt--
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if itmLock.cnt == 0 {
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delete(l.locks, itmID)
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}
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if itmLock.cnt < 0 {
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panic("sync Unlock of free Lock!!")
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}
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l.lkMux.Unlock()
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}
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func (l *multiLock) RUnlock(itmID interface{}) {
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l.lkMux.Lock()
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itmLock, exists := l.locks[itmID]
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if !exists {
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panic("sync Unlock of non existent lock!!")
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}
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itmLock.lk.RUnlock()
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itmLock.cnt--
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if itmLock.cnt == 0 {
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delete(l.locks, itmID)
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}
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if itmLock.cnt < 0 {
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panic("sync Unlock of free Lock!!")
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}
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l.lkMux.Unlock()
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}
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