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peer_cache.go
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peer_cache.go
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package tinder
import (
"context"
"sync"
"time"
"github.com/libp2p/go-libp2p/core/peer"
ma "github.com/multiformats/go-multiaddr"
"berty.tech/weshnet/internal/notify"
)
type PeersUpdate map[peer.ID]time.Time
func (current PeersUpdate) HasUpdate(tu *topicUpdate) []peer.ID {
peers := []peer.ID{}
for p, update := range tu.peerUpdate {
if lastUpdate, ok := current[p]; !ok || update.After(lastUpdate) {
current[p] = update
peers = append(peers, p)
}
}
return peers
}
type topicUpdate struct {
peerUpdate map[peer.ID]time.Time
notify *notify.Notify
}
type peersCache struct {
topics map[string]*topicUpdate
muCache sync.RWMutex
peers map[peer.ID]peer.AddrInfo
muPeers sync.RWMutex
}
func newPeerCache() *peersCache {
return &peersCache{
topics: make(map[string]*topicUpdate),
peers: make(map[peer.ID]peer.AddrInfo),
}
}
func (c *peersCache) UpdatePeer(topic string, p peer.AddrInfo) (isNew bool) {
c.muPeers.Lock()
defer c.muPeers.Unlock()
tu := c.getTopicUpdate(topic)
// update peer update time
tu.notify.L.Lock()
defer tu.notify.L.Unlock()
_, exist := tu.peerUpdate[p.ID]
// do we already know this peer ?
if prev, ok := c.peers[p.ID]; ok {
if combined := mergeAddrInfos(prev, p); combined != nil {
c.peers[p.ID] = *combined
} else if exist {
// we already know this peer, and no change have been provided
return
}
} else {
c.peers[p.ID] = p
}
t := time.Now()
tu.peerUpdate[p.ID] = t
// notify topic that peers has been updated
tu.notify.Broadcast()
return true
}
func (c *peersCache) GetPeers(ids ...peer.ID) (peers []peer.AddrInfo) {
c.muPeers.RLock()
peers = make([]peer.AddrInfo, len(ids))
for i, id := range ids {
peers[i] = c.peers[id]
}
c.muPeers.RUnlock()
return
}
func (c *peersCache) GetPeersForTopics(topic string) (peers []peer.AddrInfo) {
c.muPeers.RLock()
defer c.muPeers.RUnlock()
tu := c.getTopicUpdate(topic)
tu.notify.L.Lock()
defer tu.notify.L.Unlock()
i := 0
peers = make([]peer.AddrInfo, len(tu.peerUpdate))
for peer := range tu.peerUpdate {
peers[i] = c.peers[peer]
i++
}
return
}
func (c *peersCache) WaitForPeerUpdate(ctx context.Context, topic string, current PeersUpdate) (updated []peer.ID, ok bool) {
tu := c.getTopicUpdate(topic)
tu.notify.L.Lock()
for ok = true; ok; {
// check if there are some diff between local state and the current state
if updated = current.HasUpdate(tu); !ok || len(updated) > 0 {
break // we got some update, leave the loop
}
// wait until there is an update on this group or context expire
// unlock notify locker
ok = tu.notify.Wait(ctx)
}
tu.notify.L.Unlock()
return
}
func (c *peersCache) RemoveFromCache(ctx context.Context, topic string, p peer.ID) (ok bool) {
c.muCache.Lock()
var tu *topicUpdate
if tu, ok = c.topics[topic]; ok {
if _, ok = tu.peerUpdate[p]; ok {
delete(tu.peerUpdate, p)
}
}
c.muCache.Unlock()
return
}
func (c *peersCache) getTopicUpdate(topic string) *topicUpdate {
c.muCache.Lock()
tu, ok := c.topics[topic]
if !ok {
tu = &topicUpdate{
peerUpdate: make(map[peer.ID]time.Time),
notify: notify.New(&sync.Mutex{}),
}
c.topics[topic] = tu
}
c.muCache.Unlock()
return tu
}
func mergeAddrInfos(prevAi, newAi peer.AddrInfo) *peer.AddrInfo {
combinedAddrs := uniqueAddrs(prevAi.Addrs, newAi.Addrs)
if len(combinedAddrs) > len(prevAi.Addrs) {
combinedAi := &peer.AddrInfo{ID: prevAi.ID, Addrs: combinedAddrs}
return combinedAi
}
return nil
}
// mergeAddrs merges input address lists, leave only unique addresses
func uniqueAddrs(addrss ...[]ma.Multiaddr) (uniqueAddrs []ma.Multiaddr) {
exists := make(map[string]bool)
for _, addrs := range addrss {
for _, addr := range addrs {
k := string(addr.Bytes())
if exists[k] {
continue
}
exists[k] = true
uniqueAddrs = append(uniqueAddrs, addr)
}
}
return uniqueAddrs
}