package tcp import ( "net" "sync" "time" "github.com/v2ray/v2ray-core/common/signal" ) type AwaitingConnection struct { conn net.Conn expire time.Time } func (this *AwaitingConnection) Expired() bool { return this.expire.Before(time.Now()) } type ConnectionCache struct { sync.Mutex cache map[string][]*AwaitingConnection cleanupOnce signal.Once } func NewConnectionCache() *ConnectionCache { return &ConnectionCache{ cache: make(map[string][]*AwaitingConnection), } } func (this *ConnectionCache) Cleanup() { defer this.cleanupOnce.Reset() for len(this.cache) > 0 { time.Sleep(time.Second * 4) this.Lock() for key, value := range this.cache { size := len(value) changed := false for i := 0; i < size; { if value[i].Expired() { value[i].conn.Close() value[i] = value[size-1] size-- changed = true } else { i++ } } if changed { for i := size; i < len(value); i++ { value[i] = nil } value = value[:size] this.cache[key] = value } } this.Unlock() } } func (this *ConnectionCache) Recycle(dest string, conn net.Conn) { this.Lock() defer this.Unlock() aconn := &AwaitingConnection{ conn: conn, expire: time.Now().Add(time.Second * 4), } var list []*AwaitingConnection if v, found := this.cache[dest]; found { v = append(v, aconn) list = v } else { list = []*AwaitingConnection{aconn} } this.cache[dest] = list go this.cleanupOnce.Do(this.Cleanup) } func FindFirstValid(list []*AwaitingConnection) int { for idx, conn := range list { if !conn.Expired() { return idx } go conn.conn.Close() } return -1 } func (this *ConnectionCache) Get(dest string) net.Conn { this.Lock() defer this.Unlock() list, found := this.cache[dest] if !found { return nil } firstValid := FindFirstValid(list) if firstValid == -1 { delete(this.cache, dest) return nil } res := list[firstValid].conn list = list[firstValid+1:] this.cache[dest] = list return res }