118 lines
2.4 KiB
Go
118 lines
2.4 KiB
Go
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package dht
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import "errors"
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// Node table, with indexes on distance from root ID to bucket, and node addr.
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type table struct {
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rootID int160
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k int
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buckets [160]bucket
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addrs map[string]map[int160]struct{}
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}
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func (tbl *table) addrNodes(addr Addr) []*node {
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a := tbl.addrs[addr.String()]
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ret := make([]*node, 0, len(a))
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for id := range a {
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ret = append(ret, tbl.getNode(addr, id))
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}
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return ret
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}
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func (tbl *table) dropNode(n *node) {
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as := n.addr.String()
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if _, ok := tbl.addrs[as][n.id]; !ok {
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panic("missing id for addr")
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}
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delete(tbl.addrs[as], n.id)
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if len(tbl.addrs[as]) == 0 {
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delete(tbl.addrs, as)
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}
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b := tbl.bucketForID(n.id)
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if _, ok := b.nodes[n]; !ok {
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panic("expected node in bucket")
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}
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delete(b.nodes, n)
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}
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func (tbl *table) bucketForID(id int160) *bucket {
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return &tbl.buckets[tbl.bucketIndex(id)]
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}
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func (tbl *table) numNodes() (num int) {
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for _, b := range tbl.buckets {
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num += b.Len()
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}
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return
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}
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func (tbl *table) bucketIndex(id int160) int {
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if id == tbl.rootID {
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panic("nobody puts the root ID in a bucket")
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}
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var a int160
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a.Xor(&tbl.rootID, &id)
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index := 160 - a.BitLen()
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return index
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}
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func (tbl *table) forNodes(f func(*node) bool) bool {
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for _, b := range tbl.buckets {
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if !b.EachNode(f) {
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return false
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}
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}
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return true
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}
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func (tbl *table) getNode(addr Addr, id int160) *node {
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if id == tbl.rootID {
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return nil
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}
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return tbl.buckets[tbl.bucketIndex(id)].GetNode(addr, id)
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}
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func (tbl *table) closestNodes(k int, target int160, filter func(*node) bool) (ret []*node) {
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for bi := func() int {
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if target == tbl.rootID {
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return len(tbl.buckets) - 1
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} else {
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return tbl.bucketIndex(target)
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}
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}(); bi >= 0 && len(ret) < k; bi-- {
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for n := range tbl.buckets[bi].nodes {
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if filter(n) {
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ret = append(ret, n)
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}
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}
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}
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// TODO: Keep only the closest.
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if len(ret) > k {
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ret = ret[:k]
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}
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return
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}
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func (tbl *table) addNode(n *node) error {
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if n.id == tbl.rootID {
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return errors.New("is root id")
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}
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b := &tbl.buckets[tbl.bucketIndex(n.id)]
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if b.GetNode(n.addr, n.id) != nil {
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return errors.New("already present")
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}
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if b.Len() >= tbl.k {
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return errors.New("bucket is full")
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}
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b.AddNode(n, tbl.k)
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if tbl.addrs == nil {
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tbl.addrs = make(map[string]map[int160]struct{}, 160*tbl.k)
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}
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as := n.addr.String()
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if tbl.addrs[as] == nil {
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tbl.addrs[as] = make(map[int160]struct{}, 1)
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}
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tbl.addrs[as][n.id] = struct{}{}
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return nil
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}
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