Cache the XOR DHT Id for a peerID (#67)

* cache the XOR DHT ID for a peerId

bucket.go

@@ -9,12 +9,15 @@ import (
 	"github.com/libp2p/go-libp2p-core/peer"
 )
 
-// PeerInfo holds all related information for a peer in the K-Bucket.
-type PeerInfo struct {
+// peerInfo holds all related information for a peer in the K-Bucket.
+type peerInfo struct {
 	Id peer.ID
 	// lastSuccessfulOutboundQuery is the time instant when we last made a successful
 	// outbound query to this peer
 	lastSuccessfulOutboundQuery time.Time
+
+	// Id of the peer in the DHT XOR keyspace
+	dhtId ID
 }
 
 // bucket holds a list of peers.
@@ -34,10 +37,10 @@ func newBucket() *bucket {
 
 // returns all peers in the bucket
 // it is safe for the caller to modify the returned objects as it is a defensive copy
-func (b *bucket) peers() []PeerInfo {
-	var ps []PeerInfo
+func (b *bucket) peers() []peerInfo {
+	var ps []peerInfo
 	for e := b.list.Front(); e != nil; e = e.Next() {
-		p := e.Value.(*PeerInfo)
+		p := e.Value.(*peerInfo)
 		ps = append(ps, *p)
 	}
 	return ps
@@ -47,7 +50,7 @@ func (b *bucket) peers() []PeerInfo {
 func (b *bucket) peerIds() []peer.ID {
 	ps := make([]peer.ID, 0, b.list.Len())
 	for e := b.list.Front(); e != nil; e = e.Next() {
-		p := e.Value.(*PeerInfo)
+		p := e.Value.(*peerInfo)
 		ps = append(ps, p.Id)
 	}
 	return ps
@@ -55,10 +58,10 @@ func (b *bucket) peerIds() []peer.ID {
 
 // returns the peer with the given Id if it exists
 // returns nil if the peerId does not exist
-func (b *bucket) getPeer(p peer.ID) *PeerInfo {
+func (b *bucket) getPeer(p peer.ID) *peerInfo {
 	for e := b.list.Front(); e != nil; e = e.Next() {
-		if e.Value.(*PeerInfo).Id == p {
-			return e.Value.(*PeerInfo)
+		if e.Value.(*peerInfo).Id == p {
+			return e.Value.(*peerInfo)
 		}
 	}
 	return nil
@@ -68,7 +71,7 @@ func (b *bucket) getPeer(p peer.ID) *PeerInfo {
 // returns true if successful, false otherwise.
 func (b *bucket) remove(id peer.ID) bool {
 	for e := b.list.Front(); e != nil; e = e.Next() {
-		if e.Value.(*PeerInfo).Id == id {
+		if e.Value.(*peerInfo).Id == id {
 			b.list.Remove(e)
 			return true
 		}
@@ -79,13 +82,13 @@ func (b *bucket) remove(id peer.ID) bool {
 func (b *bucket) moveToFront(id peer.ID) {
 
 	for e := b.list.Front(); e != nil; e = e.Next() {
-		if e.Value.(*PeerInfo).Id == id {
+		if e.Value.(*peerInfo).Id == id {
 			b.list.MoveToFront(e)
 		}
 	}
 }
 
-func (b *bucket) pushFront(p *PeerInfo) {
+func (b *bucket) pushFront(p *peerInfo) {
 	b.list.PushFront(p)
 }
 
@@ -102,8 +105,8 @@ func (b *bucket) split(cpl int, target ID) *bucket {
 	newbuck.list = out
 	e := b.list.Front()
 	for e != nil {
-		peerID := ConvertPeerID(e.Value.(*PeerInfo).Id)
-		peerCPL := CommonPrefixLen(peerID, target)
+		pDhtId := e.Value.(*peerInfo).dhtId
+		peerCPL := CommonPrefixLen(pDhtId, target)
 		if peerCPL > cpl {
 			cur := e
 			out.PushBack(e.Value)

sorting.go

@@ -28,17 +28,17 @@ func (pds *peerDistanceSorter) Less(a, b int) bool {
 }
 
 // Append the peer.ID to the sorter's slice. It may no longer be sorted.
-func (pds *peerDistanceSorter) appendPeer(p peer.ID) {
+func (pds *peerDistanceSorter) appendPeer(p peer.ID, pDhtId ID) {
 	pds.peers = append(pds.peers, peerDistance{
 		p:        p,
-		distance: xor(pds.target, ConvertPeerID(p)),
+		distance: xor(pds.target, pDhtId),
 	})
 }
 
 // Append the peer.ID values in the list to the sorter's slice. It may no longer be sorted.
 func (pds *peerDistanceSorter) appendPeersFromList(l *list.List) {
 	for e := l.Front(); e != nil; e = e.Next() {
-		pds.appendPeer(e.Value.(*PeerInfo).Id)
+		pds.appendPeer(e.Value.(*peerInfo).Id, e.Value.(*peerInfo).dhtId)
 	}
 }
 
@@ -53,7 +53,7 @@ func SortClosestPeers(peers []peer.ID, target ID) []peer.ID {
 		target: target,
 	}
 	for _, p := range peers {
-		sorter.appendPeer(p)
+		sorter.appendPeer(p, ConvertPeerID(p))
 	}
 	sorter.sort()
 	out := make([]peer.ID, 0, sorter.Len())

table.go

@@ -129,7 +129,7 @@ func (rt *RoutingTable) addPeer(p peer.ID, queryPeer bool) (bool, error) {
 
 	// We have enough space in the bucket (whether spawned or grouped).
 	if bucket.len() < rt.bucketsize {
-		bucket.pushFront(&PeerInfo{p, lastSuccessfulOutboundQuery})
+		bucket.pushFront(&peerInfo{p, lastSuccessfulOutboundQuery, ConvertPeerID(p)})
 		rt.PeerAdded(p)
 		return true, nil
 	}
@@ -143,7 +143,7 @@ func (rt *RoutingTable) addPeer(p peer.ID, queryPeer bool) (bool, error) {
 
 		// push the peer only if the bucket isn't overflowing after slitting
 		if bucket.len() < rt.bucketsize {
-			bucket.pushFront(&PeerInfo{p, lastSuccessfulOutboundQuery})
+			bucket.pushFront(&peerInfo{p, lastSuccessfulOutboundQuery, ConvertPeerID(p)})
 			rt.PeerAdded(p)
 			return true, nil
 		}
@@ -156,7 +156,7 @@ func (rt *RoutingTable) addPeer(p peer.ID, queryPeer bool) (bool, error) {
 		if float64(time.Since(pc.lastSuccessfulOutboundQuery)) > rt.maxLastSuccessfulOutboundThreshold {
 			// let's evict it and add the new peer
 			if bucket.remove(pc.Id) {
-				bucket.pushFront(&PeerInfo{p, lastSuccessfulOutboundQuery})
+				bucket.pushFront(&peerInfo{p, lastSuccessfulOutboundQuery, ConvertPeerID(p)})
 				rt.PeerAdded(p)
 				return true, nil
 			}
@@ -334,7 +334,7 @@ func (rt *RoutingTable) Print() {
 		fmt.Printf("\tbucket: %d\n", i)
 
 		for e := b.list.Front(); e != nil; e = e.Next() {
-			p := e.Value.(*PeerInfo).Id
+			p := e.Value.(*peerInfo).Id
 			fmt.Printf("\t\t- %s %s\n", p.Pretty(), rt.metrics.LatencyEWMA(p).String())
 		}
 	}

table_test.go

@@ -33,7 +33,7 @@ func TestBucket(t *testing.T) {
 	peers := make([]peer.ID, 100)
 	for i := 0; i < 100; i++ {
 		peers[i] = test.RandPeerIDFatal(t)
-		b.pushFront(&PeerInfo{peers[i], testTime1})
+		b.pushFront(&peerInfo{peers[i], testTime1, ConvertPeerID(peers[i])})
 	}
 
 	local := test.RandPeerIDFatal(t)
@@ -46,6 +46,7 @@ func TestBucket(t *testing.T) {
 	p := b.getPeer(peers[i])
 	require.NotNil(t, p)
 	require.Equal(t, peers[i], p.Id)
+	require.Equal(t, ConvertPeerID(peers[i]), p.dhtId)
 	require.EqualValues(t, testTime1, p.lastSuccessfulOutboundQuery)
 
 	// mark as missing
@@ -58,7 +59,7 @@ func TestBucket(t *testing.T) {
 	spl := b.split(0, ConvertPeerID(local))
 	llist := b.list
 	for e := llist.Front(); e != nil; e = e.Next() {
-		p := ConvertPeerID(e.Value.(*PeerInfo).Id)
+		p := ConvertPeerID(e.Value.(*peerInfo).Id)
 		cpl := CommonPrefixLen(p, localID)
 		if cpl > 0 {
 			t.Fatalf("split failed. found id with cpl > 0 in 0 bucket")
@@ -67,7 +68,7 @@ func TestBucket(t *testing.T) {
 
 	rlist := spl.list
 	for e := rlist.Front(); e != nil; e = e.Next() {
-		p := ConvertPeerID(e.Value.(*PeerInfo).Id)
+		p := ConvertPeerID(e.Value.(*peerInfo).Id)
 		cpl := CommonPrefixLen(p, localID)
 		if cpl == 0 {
 			t.Fatalf("split failed. found id with cpl == 0 in non 0 bucket")