rename AckHandlerNew to AckHandler

ref #55

ackhandler/received_packet_history.go

@@ -0,0 +1,106 @@
+package ackhandler
+
+import (
+	"sync"
+
+	"github.com/lucas-clemente/quic-go/frames"
+	"github.com/lucas-clemente/quic-go/protocol"
+	"github.com/lucas-clemente/quic-go/utils"
+)
+
+type receivedPacketHistory struct {
+	ranges *utils.PacketIntervalList
+
+	mutex sync.RWMutex
+}
+
+// newReceivedPacketHistory creates a new received packet history
+func newReceivedPacketHistory() *receivedPacketHistory {
+	return &receivedPacketHistory{
+		ranges: utils.NewPacketIntervalList(),
+	}
+}
+
+// ReceivedPacket registers a packet with PacketNumber p and updates the ranges
+func (h *receivedPacketHistory) ReceivedPacket(p protocol.PacketNumber) {
+	h.mutex.Lock()
+	defer h.mutex.Unlock()
+
+	if h.ranges.Len() == 0 {
+		h.ranges.PushBack(utils.PacketInterval{Start: p, End: p})
+		return
+	}
+
+	for el := h.ranges.Back(); el != nil; el = el.Prev() {
+		// p already included in an existing range. Nothing to do here
+		if p >= el.Value.Start && p <= el.Value.End {
+			return
+		}
+
+		var rangeExtended bool
+		if el.Value.End == p-1 { // extend a range at the end
+			rangeExtended = true
+			el.Value.End = p
+		} else if el.Value.Start == p+1 { // extend a range at the beginning
+			rangeExtended = true
+			el.Value.Start = p
+		}
+
+		// if a range was extended (either at the beginning or at the end, maybe it is possible to merge two ranges into one)
+		if rangeExtended {
+			prev := el.Prev()
+			if prev != nil && prev.Value.End+1 == el.Value.Start { // merge two ranges
+				prev.Value.End = el.Value.End
+				h.ranges.Remove(el)
+				return
+			}
+			return // if the two ranges were not merge, we're done here
+		}
+
+		// create a new range at the end
+		if p > el.Value.End {
+			h.ranges.InsertAfter(utils.PacketInterval{Start: p, End: p}, el)
+			return
+		}
+	}
+
+	// create a new range at the beginning
+	h.ranges.InsertBefore(utils.PacketInterval{Start: p, End: p}, h.ranges.Front())
+}
+
+func (h *receivedPacketHistory) DeleteBelow(leastUnacked protocol.PacketNumber) {
+	h.mutex.Lock()
+	defer h.mutex.Unlock()
+
+	nextEl := h.ranges.Front()
+	for el := h.ranges.Front(); nextEl != nil; el = nextEl {
+		nextEl = el.Next()
+
+		if leastUnacked > el.Value.Start && leastUnacked <= el.Value.End {
+			el.Value.Start = leastUnacked
+		}
+		if el.Value.End < leastUnacked { // delete a whole range
+			h.ranges.Remove(el)
+		} else {
+			return
+		}
+	}
+}
+
+// GetAckRanges gets a slice of all AckRanges that can be used in an AckFrame
+func (h *receivedPacketHistory) GetAckRanges() []frames.AckRange {
+	h.mutex.RLock()
+	defer h.mutex.RUnlock()
+
+	if h.ranges.Len() == 0 {
+		return nil
+	}
+
+	var ackRanges []frames.AckRange
+
+	for el := h.ranges.Back(); el != nil; el = el.Prev() {
+		ackRanges = append(ackRanges, frames.AckRange{FirstPacketNumber: el.Value.Start, LastPacketNumber: el.Value.End})
+	}
+
+	return ackRanges
+}