voidwalker/util/ml/multiplelock.go
Niko Storni 374ec482cd make timeout configurable
don't republish thumbs that were published from previous channels
2020-06-04 21:29:02 +02:00

96 lines
1.8 KiB
Go

package ml
import (
"sync"
)
// MultipleLock is the main interface for multiLock based on key
type MultipleLock interface {
// Lock base on the key
Lock(interface{})
// RLock multiLock the rw for reading
RLock(interface{})
// Unlock the key
Unlock(interface{})
// RUnlock the the read multiLock
RUnlock(interface{})
}
func NewMultipleLock() MultipleLock {
return &multiLock{
locks: make(map[interface{}]*itemLock),
lkMux: sync.Mutex{},
}
}
type itemLock struct {
lk *sync.RWMutex
cnt int64
}
// multiLock is an optimized locking system per locking key
type multiLock struct {
locks map[interface{}]*itemLock
lkMux sync.Mutex // protects the locks
}
func (l *multiLock) Lock(itmID interface{}) {
l.lkMux.Lock()
itmLock, exists := l.locks[itmID]
if !exists {
itmLock = &itemLock{&sync.RWMutex{}, 0}
l.locks[itmID] = itmLock
}
itmLock.cnt++
l.lkMux.Unlock()
itmLock.lk.Lock()
}
func (l *multiLock) RLock(itmID interface{}) {
l.lkMux.Lock()
itmLock, exists := l.locks[itmID]
if !exists {
itmLock = &itemLock{&sync.RWMutex{}, 0}
l.locks[itmID] = itmLock
}
itmLock.cnt++
l.lkMux.Unlock()
itmLock.lk.RLock()
}
func (l *multiLock) Unlock(itmID interface{}) {
l.lkMux.Lock()
itmLock, exists := l.locks[itmID]
if !exists {
panic("sync Unlock of non existent lock!!")
}
itmLock.lk.Unlock()
itmLock.cnt--
if itmLock.cnt == 0 {
delete(l.locks, itmID)
}
if itmLock.cnt < 0 {
panic("sync Unlock of free Lock!!")
}
l.lkMux.Unlock()
}
func (l *multiLock) RUnlock(itmID interface{}) {
l.lkMux.Lock()
itmLock, exists := l.locks[itmID]
if !exists {
panic("sync Unlock of non existent lock!!")
}
itmLock.lk.RUnlock()
itmLock.cnt--
if itmLock.cnt == 0 {
delete(l.locks, itmID)
}
if itmLock.cnt < 0 {
panic("sync Unlock of free Lock!!")
}
l.lkMux.Unlock()
}