132 lines
2.6 KiB
Go
132 lines
2.6 KiB
Go
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package locks
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import (
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"fmt"
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"sync"
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"time"
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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(key string)
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RLock(key string)
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Unlock(key string)
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RUnlock(key string)
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}
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func NewMultipleLock() MultipleLock {
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return &multiLock{
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locks: make(map[string]*itemLock),
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mu: 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[string]*itemLock
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mu sync.Mutex // synchronize reads/writes to locks map
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}
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func debugPrint(format string, a ...interface{}) {
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debugEnabled := false
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if debugEnabled {
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a = append(a, time.Now().Format("04:05.000000"))
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fmt.Printf(format+" at %s\n", a...)
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}
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}
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func (ml *multiLock) Lock(key string) {
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debugPrint("mutex requested %s", key)
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ml.mu.Lock()
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debugPrint("mutex acquired %s", key)
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itmLock, exists := ml.locks[key]
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if !exists {
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debugPrint("new lock created %s", key)
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itmLock = &itemLock{&sync.RWMutex{}, 0}
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ml.locks[key] = itmLock
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}
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itmLock.cnt++
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debugPrint("releasing mutex %s", key)
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ml.mu.Unlock()
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debugPrint("Lock requested %s", key)
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itmLock.lk.Lock()
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debugPrint("Lock acquired %s", key)
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}
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func (ml *multiLock) RLock(key string) {
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debugPrint("mutex requested %s", key)
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ml.mu.Lock()
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debugPrint("mutex acquired %s", key)
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itmLock, exists := ml.locks[key]
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if !exists {
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debugPrint("new lock created for %s", key)
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itmLock = &itemLock{&sync.RWMutex{}, 0}
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ml.locks[key] = itmLock
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}
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itmLock.cnt++
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debugPrint("releasing mutex %s", key)
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ml.mu.Unlock()
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debugPrint("RLock requested %s", key)
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itmLock.lk.RLock()
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debugPrint("RLock acquired %s", key)
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}
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func (ml *multiLock) Unlock(key string) {
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debugPrint("mutex requested %s", key)
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ml.mu.Lock()
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debugPrint("mutex acquired %s", key)
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itmLock, exists := ml.locks[key]
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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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debugPrint("Unlock %s", key)
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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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debugPrint("delete lock %s", key)
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delete(ml.locks, key)
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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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debugPrint("releasing mutex %s", key)
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ml.mu.Unlock()
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}
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func (ml *multiLock) RUnlock(key string) {
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debugPrint("mutex requested %s", key)
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ml.mu.Lock()
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debugPrint("mutex acquired %s", key)
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itmLock, exists := ml.locks[key]
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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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debugPrint("RUnlock %s", key)
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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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debugPrint("delete lock %s", key)
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delete(ml.locks, key)
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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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debugPrint("releasing mutex %s", key)
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ml.mu.Unlock()
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}
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