add update KBucket table

kademlia.go

@@ -75,13 +75,15 @@ func (n *Node) Update(o ListedNode) {
 	k := n.KBucket(o.ID)
 	kb := n.KBuckets[k]
 	if len(kb) >= KBucketSize {
-		// TODO ping the kb[0], and if no response, delete it, and add the current o (ID)
+		// if n.KBuckets[k] is alrady full, perform ping of the first element
+		n.Ping(k, o)
 		return
 	}
 	// check that is not already in the list
-	exist, _ := existsInListedNodes(n.KBuckets[k], o)
+	exist, pos := existsInListedNodes(n.KBuckets[k], o)
 	if exist {
-		// update position to the bottom
+		// update position of o to the bottom
+		n.KBuckets[k] = moveToBottom(n.KBuckets[k], pos)
 		return
 	}
 	// not exists, add it to the kBucket
@@ -89,6 +91,13 @@ func (n *Node) Update(o ListedNode) {
 	return
 }
 
+func (n *Node) Ping(k int, o ListedNode) {
+	// TODO when rpc layer is done
+	// ping the n.KBuckets[k][0] (using goroutine)
+	// if no response (timeout), delete it and add 'o'
+	// n.KBuckets[k][0] = o
+}
+
 func existsInListedNodes(lns []ListedNode, ln ListedNode) (bool, int) {
 	for i, v := range lns {
 		if v.ID.Equal(ln.ID) {
@@ -97,3 +106,10 @@ func existsInListedNodes(lns []ListedNode, ln ListedNode) (bool, int) {
 	}
 	return false, 0
 }
+
+func moveToBottom(kb []ListedNode, k int) []ListedNode {
+	e := kb[k]
+	kb = append(kb[:k], kb[k+1:]...)
+	kb = append(kb[:], e)
+	return kb
+}

kademlia_test.go

@@ -7,7 +7,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-var debug = true
+var debug = false
 
 func TestCountZeros(t *testing.T) {
 	zeroes := []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
@@ -51,10 +51,7 @@ func TestNodeKBucket(t *testing.T) {
 	assert.Equal(t, 159, d)
 }
 
-func TestUpdate(t *testing.T) {
-	nodeA, err := LoadNode("0fd85ddddf15aeec2d5d8b01b013dbca030a18d7")
-	assert.Nil(t, err)
-
+func prepareTestListedNodes() []ListedNode {
 	lnIDs := []string{
 		"c48d8b53dbefb609ed4e94d386dd5b22efcb2c5b",
 		"420bfebd44fc62615253224328f40f29c9b225fa",
@@ -76,13 +73,35 @@ func TestUpdate(t *testing.T) {
 		"0750931c40a52a2facd220a02851f7d34f95e1fa",
 		"ebfba615ac50bcd0f5c2420741d032e885abf576",
 	}
+	var lns []ListedNode
 	for i := 0; i < len(lnIDs); i++ {
 		idI, err := IDFromString(lnIDs[i])
-		assert.Nil(t, err)
+		if err != nil {
+			panic(err)
+		}
 		lnI := ListedNode{
 			ID:   idI,
 			Addr: "",
 		}
+		lns = append(lns, lnI)
+	}
+	return lns
+}
+
+func TestMoveToBottom(t *testing.T) {
+	lns := prepareTestListedNodes()
+	movedElem := lns[3]
+	assert.NotEqual(t, movedElem, lns[len(lns)-1])
+	lns = moveToBottom(lns, 3)
+	assert.Equal(t, movedElem, lns[len(lns)-1])
+}
+
+func TestUpdate(t *testing.T) {
+	nodeA, err := LoadNode("0fd85ddddf15aeec2d5d8b01b013dbca030a18d7")
+	assert.Nil(t, err)
+
+	lns := prepareTestListedNodes()
+	for _, lnI := range lns {
 		nodeA.Update(lnI)
 	}