Golang atomic.CompareAndSwapInt64函數代碼示例

func (node *Node) addChar(c *byte, w *wrk) *Node {
	*w.i = int64(*c - 'a')
	if *w.i < 0 || *w.i > 25 {
		return node
	}
	if w.tmp = (atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&(node.ptrs[*w.i]))))); w.tmp == nil {
		atomic.CompareAndSwapPointer((*unsafe.Pointer)(unsafe.Pointer((&node.ptrs[*w.i]))), w.tmp, unsafe.Pointer(newNode()))
		w.mn, w.mx = atomic.LoadInt64(&(node.minIdx)), atomic.LoadInt64(&(node.maxIdx))
		for {
			switch {
			case w.mn > *w.i:
				if !atomic.CompareAndSwapInt64(&(node.minIdx), w.mn, *w.i) {
					w.mn = atomic.LoadInt64(&(node.minIdx))
				} else {
					w.mn = *w.i
				}
			case w.mx < *w.i:
				if !atomic.CompareAndSwapInt64(&(node.maxIdx), w.mx, *w.i) {
					w.mx = atomic.LoadInt64(&(node.maxIdx))
				} else {
					w.mx = *w.i
				}
			default:
				return node.ptrs[*w.i]
			}
		}
	}
	return node.ptrs[*w.i]
}

// request a token; returns true if token obtained, false otherwise
func (tbq *TBucketQ) GetTok() bool {
	// attempt to obtain token from bucket
	for {
		if toks := atomic.LoadInt64(&tbq.tokens); toks > 0 {
			if atomic.CompareAndSwapInt64(&tbq.tokens, toks, toks-1) {
				return true
			}
			continue
		}
		break
	}
	// no tokens in the bucket, attempt to get on the queue
	var done bool
	for !done {
		if qcnt := atomic.LoadInt64(&tbq.qcnt); qcnt < tbq.maxq {
			done = atomic.CompareAndSwapInt64(&tbq.qcnt, qcnt, qcnt+1)
		} else {
			// queue is full, return false
			return false
		}
	}
	// on queue, wait until token received
	<-tbq.qch
	return true
}

// Decrement decrements the value of c by 1.
func (c *Counter) Decrement() {
	old := atomic.LoadInt64(&c.v)
	swapped := atomic.CompareAndSwapInt64(&c.v, old, old-1)
	for !swapped {
		old = atomic.LoadInt64(&c.v)
		swapped = atomic.CompareAndSwapInt64(&c.v, old, old-1)
	}
}

// InsertRows inserts rows into the partition.
func (p *MemoryPartition) InsertRows(rows []partition.Row) error {
	if p.readOnly {
		return errors.New("partition/memory: read only")
	}

	if p.wal != nil {
		_, err := p.wal.Append(wal.WALEntry{
			Operation: wal.OperationInsert,
			Rows:      rows,
		})

		if err != nil {
			return err
		}
	}

	var (
		minTS int64
		maxTS int64
	)

	for i, row := range rows {
		if i == 0 {
			minTS = row.Timestamp
			maxTS = row.Timestamp
		}

		if row.Timestamp < minTS {
			minTS = row.Timestamp
		}

		if row.Timestamp > maxTS {
			maxTS = row.Timestamp
		}

		source := p.getOrCreateSource(row.Source)
		metric := source.getOrCreateMetric(row.Metric)
		metric.insertPoints([]partition.Point{row.Point})
	}

	for min := atomic.LoadInt64(&p.minTS); min > minTS; min = atomic.LoadInt64(&p.minTS) {
		if atomic.CompareAndSwapInt64(&p.minTS, min, minTS) {
			break
		}
	}

	for max := atomic.LoadInt64(&p.maxTS); max < maxTS; max = atomic.LoadInt64(&p.maxTS) {
		if atomic.CompareAndSwapInt64(&p.maxTS, max, maxTS) {
			break
		}
	}

	return nil
}

// grant tokens to requests waiting in the queue or add a token to the bucket
// each time the ticker goes off
func (tbq *TBucketQ) tick() {
	for {
		select {
		case <-tbq.cch:
			// close event received, stop timer and return
			tbq.ticker.Stop()
			return
		case <-tbq.prch:
			// pause event received, listen for stop or resume events
			select {
			case <-tbq.cch:
				// close event received, stop timer and return
				tbq.ticker.Stop()
				return
			case <-tbq.prch:
				// resume event received
			}
		case <-tbq.ticker.C:
			// add token to queue channel if there are any requests waiting
			burst := tbq.burst
			if atomic.LoadInt64(&tbq.qcnt) > 0 {
				for i := int64(0); i < tbq.burst; i++ {
					if qcnt := atomic.LoadInt64(&tbq.qcnt); qcnt > 0 {
						tbq.qch <- struct{}{}
						atomic.AddInt64(&tbq.qcnt, -1)
						burst -= 1
					} else {
						continue
					}
				}
			}
			if burst == 0 {
				continue
			}
			// no requests remaining in queue, attempt to add
			// token(s) to the bucket
			var done bool
			for !done {
				// add token(s) to the bucket if not already full
				if toks := atomic.LoadInt64(&tbq.tokens); toks < tbq.bsize {
					if toks+burst >= tbq.bsize {
						done = atomic.CompareAndSwapInt64(&tbq.tokens, toks, tbq.bsize)
					} else {
						done = atomic.CompareAndSwapInt64(&tbq.tokens, toks, toks+burst)
					}
				} else {
					// bucket is full, throw token(s) away
					done = true
				}
			}
		}
	}
}

// Take attempts to take n tokens out of the bucket.
// If tokens == 0, nothing will be taken.
// If n <= tokens, n tokens will be taken.
// If n > tokens, all tokens will be taken.
//
// This method is thread-safe.
func (b *Bucket) Take(n int64) (taken int64) {
	for {
		if tokens := atomic.LoadInt64(&b.tokens); tokens == 0 {
			return 0
		} else if n <= tokens {
			if !atomic.CompareAndSwapInt64(&b.tokens, tokens, tokens-n) {
				continue
			}
			return n
		} else if atomic.CompareAndSwapInt64(&b.tokens, tokens, 0) { // Spill
			return tokens
		}
	}
}

// Put attempts to add n tokens to the bucket.
// If tokens == capacity, nothing will be added.
// If n <= capacity - tokens, n tokens will be added.
// If n > capacity - tokens, capacity - tokens will be added.
//
// This method is thread-safe.
func (b *Bucket) Put(n int64) (added int64) {
	for {
		if tokens := atomic.LoadInt64(&b.tokens); tokens == b.capacity {
			return 0
		} else if left := b.capacity - tokens; n <= left {
			if !atomic.CompareAndSwapInt64(&b.tokens, tokens, tokens+n) {
				continue
			}
			return n
		} else if atomic.CompareAndSwapInt64(&b.tokens, tokens, b.capacity) {
			return left
		}
	}
}

// Run worker. Waits for tasks on channel. When receives one tries to reserve it. If succesfull
// executes the work function and signal readiness after function returned. If not able to
// reserve forgets the task completely.
func (w *Worker) Run() {
	var t *Task
	var yield chan int = make(chan int)
	for true {
		t = <-w.queue
		if t == nil {
			// stop on nil task
			break
		}
		w.ntotal += 1
		if atomic.CompareAndSwapInt64(&t.workerId, 0, w.id) {
			go func() {
				t.work(yield)
				sendOK(t.ready)
			}()
			// wait for current task to yield
			<-yield
			w.nexec += 1

			if t.next != nil {
				tn := t.next
				// schedule next task in task chain
				go func() {
					w.sched.Schedule(tn)
				}()
				t.next = nil
			}
		}

	}
	sendOK(w.sched.done)
}

//增加一個異步任務
func (m *longTimeTaskOperate) addAsync() {
	m.Add(1)
	defer func() {
		if err := recover(); err != nil {
			Tlog.Warn("異步任務["+m.taskname+"]異常退出", err)
			Tlog.Warn(string(debug.Stack()))
			atomic.AddInt64(&m.curAsyncPoolNum, -1)
		}

		//Tlog.Debug("異步任務["+m.taskname+"]退出:剩餘", m.curAsyncPoolNum)
		m.Done()
	}()
	//Tlog.Debug( "異步任務["+m.taskname+"]增加:當前數量", m.curAsyncPoolNum)
	for {
		select {

		case task := <-m.asyncchan:

			m.execTask(task)
			runtime.Gosched()
		case <-time.After(m.asyncPoolIdelTime):

			if m.curAsyncPoolNum > m.minAsyncPoolNum {
				var poolnum = m.curAsyncPoolNum
				if !atomic.CompareAndSwapInt64(&m.curAsyncPoolNum, poolnum, poolnum-1) {
					continue
				}
				//Tlog.Debug("異步任務[" + m.taskname + "]空閑退出")
				return
			}
		}
	}
}

func (p *TSimpleServer) Stop() error {
	if atomic.CompareAndSwapInt64(&p.stopped, 0, 1) {
		p.quit <- struct{}{}
		p.serverTransport.Interrupt()
	}
	return nil
}

// Accepted checks if query at this moment should be accepted or rejected.
// If accepted, the EMA rate limiter updates its current EMA
func (e *emaRateLimiter) Accepted() bool {
	now := time.Now().UnixNano()
	instWaiting := now - atomic.LoadInt64(&e.timeOfLastRequest)
	for {
		avgWaitingNs := atomic.LoadInt64(&e.avgWaitingNs)
		newavgWaitingNs := int64((1.-wq)*float64(avgWaitingNs) + wq*float64(instWaiting))
		// glog.V(3).Infof("avgWaitingNs %d newavgWaitingNs %d", avgWaitingNs, newavgWaitingNs)
		if newavgWaitingNs < e.targetWaitingNs {
			atomic.AddInt64(&e.requestThrottledCount, 1)
			return false
		}
		// if(pendingRequests.size()>maxPendingQueueLength) {
		// pendingTooLongDiscarded.incrementAndGet();
		// return false;
		// }
		atomic.StoreInt64(&e.timeOfLastRequest, now)
		newavgWaitingNs2 := newavgWaitingNs
		if !atomic.CompareAndSwapInt64(&e.avgWaitingNs, avgWaitingNs, newavgWaitingNs) {
			continue
		}
		if newavgWaitingNs2 < e.minWaitingNs {
			e.minWaitingNs = newavgWaitingNs2
		}
		atomic.AddInt64(&e.requestAcceptedCount, 1)
		break

	}
	return true
}

func Close() {
	rw.Lock()
	defer rw.Unlock()

	atomic.CompareAndSwapInt64(&flag, 0, 1)
	close(c)
}

func AtomicCompareAndSwapImpl(args *Data, env *SymbolTableFrame) (result *Data, err error) {
	atomicObj := Car(args)
	if !ObjectP(atomicObj) || ObjectType(atomicObj) != "Atomic" {
		err = ProcessError(fmt.Sprintf("atomic-compare-and-swap! expects an Atomic object but received %s.", ObjectType(atomicObj)), env)
		return
	}

	pointer := (*int64)(ObjectValue(atomicObj))

	oldObj := Cadr(args)

	if !IntegerP(oldObj) {
		err = ProcessError(fmt.Sprintf("atomic-compare-and-swap! expects an Integer as its second argument but received %s.", TypeName(TypeOf(oldObj))), env)
		return
	}

	newObj := Caddr(args)

	if !IntegerP(newObj) {
		err = ProcessError(fmt.Sprintf("atomic-compare-and-swap! expects an Integer as its third argument but received %s.", TypeName(TypeOf(newObj))), env)
		return
	}

	old := IntegerValue(oldObj)
	new := IntegerValue(newObj)

	swapped := atomic.CompareAndSwapInt64(pointer, old, new)

	return BooleanWithValue(swapped), nil
}

func (c *Client) internalConnLost(err error) {

	var clost = c.lost
	if clost == _LOSTING {
		WARN.Println(CLI, c.options.ClientID+":internalConnLost  closing quit 1")
		return
	}
	if !atomic.CompareAndSwapInt64(&c.lost, clost, _LOSTING) {
		WARN.Println(CLI, c.options.ClientID+":internalConnLost  closing quit 2")
		return
	}
	select {
	case <-c.stop:
		//someone else has already closed the channel, must be error
	default:
		close(c.stop)
	}
	c.conn.Close()
	WARN.Println(CLI, c.options.ClientID+":internalConnLost  close wait")
	c.workers.Wait()
	WARN.Println(CLI, c.options.ClientID+":internalConnLost  wait end closed:", c.options.AutoReconnect)
	if c.IsConnected() {
		if c.options.OnConnectionLost != nil {
			go c.options.OnConnectionLost(c, err)
		}
		if c.options.AutoReconnect {
			DEBUG.Println(CLI, c.options.ClientID+":auto reconnect")
			go c.reconnect()
		} else {
			c.setConnected(false)
		}
	}
}

// Tries to decrease the semaphore's value by n. Panics if n is negative. If it is smaller than n, waits until it grows
// large enough. If the cancel channel becomes readable before that happens, the request is cancelled. Returns true
// if the semaphore was decreased, false if the operation was cancelled.
func (s *Semaphore) AcquireCancellable(n int, cancel <-chan struct{}) bool {
	if n < 0 {
		panic("Semaphore.Acquire called with negative decrement")
	}
	v := atomic.LoadInt64(&s.value)
	for v >= int64(n) {
		if atomic.CompareAndSwapInt64(&s.value, v, v-int64(n)) {
			return true
		}
		v = atomic.LoadInt64(&s.value)
	}

	select {
	case <-cancel:
		return false
	case <-s.acquireMu:
	}
	defer func() {
		s.acquireMu <- struct{}{}
	}()

	v = atomic.AddInt64(&s.value, int64(-n))
	for v < 0 {
		select {
		case <-cancel:
			atomic.AddInt64(&s.value, int64(n))
			return false
		case <-s.wake:
			v = atomic.LoadInt64(&s.value)
		}
	}
	return true
}