refactor: rename PeerCache to Peers

It was never much of a cache, and that aspect of it is certainly not
its defining characteristic.

docs/architecture.txt

@@ -96,19 +96,18 @@ Router:
     directly connected neighbours via TCP. This network update message
     contains the relevant changes to the network topology due to the
     connection change. When such a message is received by a TCP
-    receiver threads, they invoke the peers cache to apply the update
-    to the local model of the network topology. This may fail for a
-    number of reasons (for example the update may contain reference to
-    peers that we have no prior knowledge of. In this case, we ignore
-    the update and send back to the peer from whom we received the
-    update a request for the complete network topology), or it may
-    apply and elicit some changes to our model. If it does elicit some
-    changes then we send out an updated update message to all our
-    peers. In this way the changes are passed quickly from peer to
-    peer based on the established connections and stop being sent once
-    a received update causes no changes to the peer's topology
-    model. Changes are additive and care is taken to ensure that no
-    loops can occur.
+    receiver threads, they apply the update to the local model of the
+    network topology. This may fail for a number of reasons (for
+    example the update may contain reference to peers that we have no
+    prior knowledge of. In this case, we ignore the update and send
+    back to the peer from whom we received the update a request for
+    the complete network topology), or it may apply and elicit some
+    changes to our model. If it does elicit some changes then we send
+    out an updated update message to all our peers. In this way the
+    changes are passed quickly from peer to peer based on the
+    established connections and stop being sent once a received update
+    causes no changes to the peer's topology model. Changes are
+    additive and care is taken to ensure that no loops can occur.
 
 
 Routing

router/peers.go

@@ -8,55 +8,55 @@ import (
 	"sync"
 )
 
-type PeerCache struct {
+type Peers struct {
 	sync.RWMutex
 	table map[PeerName]*Peer
 	onGC  func(*Peer)
 }
 
-func NewPeerCache(onGC func(*Peer)) *PeerCache {
-	return &PeerCache{table: make(map[PeerName]*Peer), onGC: onGC}
+func NewPeers(onGC func(*Peer)) *Peers {
+	return &Peers{table: make(map[PeerName]*Peer), onGC: onGC}
 }
 
-func (cache *PeerCache) FetchWithDefault(peer *Peer) *Peer {
-	cache.RLock()
-	res, found := cache.fetchAlias(peer)
-	cache.RUnlock()
+func (peers *Peers) FetchWithDefault(peer *Peer) *Peer {
+	peers.RLock()
+	res, found := peers.fetchAlias(peer)
+	peers.RUnlock()
 	if found {
 		return res
 	}
-	cache.Lock()
-	defer cache.Unlock()
-	res, found = cache.fetchAlias(peer)
+	peers.Lock()
+	defer peers.Unlock()
+	res, found = peers.fetchAlias(peer)
 	if found {
 		return res
 	}
-	cache.table[peer.Name] = peer
+	peers.table[peer.Name] = peer
 	peer.IncrementLocalRefCount()
 	return peer
 }
 
-func (cache *PeerCache) Fetch(name PeerName) (*Peer, bool) {
-	cache.RLock()
-	defer cache.RUnlock()
-	peer, found := cache.table[name]
+func (peers *Peers) Fetch(name PeerName) (*Peer, bool) {
+	peers.RLock()
+	defer peers.RUnlock()
+	peer, found := peers.table[name]
 	return peer, found // GRRR, why can't I inline this!?
 }
 
-func (cache *PeerCache) ForEach(fun func(PeerName, *Peer)) {
-	cache.RLock()
-	defer cache.RUnlock()
-	for name, peer := range cache.table {
+func (peers *Peers) ForEach(fun func(PeerName, *Peer)) {
+	peers.RLock()
+	defer peers.RUnlock()
+	for name, peer := range peers.table {
 		fun(name, peer)
 	}
 }
 
-func (cache *PeerCache) ApplyUpdate(update []byte, router *Router) ([]byte, error) {
-	cache.Lock()
+func (peers *Peers) ApplyUpdate(update []byte, router *Router) ([]byte, error) {
+	peers.Lock()
 
-	newPeers, decodedUpdate, decodedConns, err := cache.decodeUpdate(update, router)
+	newPeers, decodedUpdate, decodedConns, err := peers.decodeUpdate(update, router)
 	if err != nil {
-		cache.Unlock()
+		peers.Unlock()
 		return nil, err
 	}
 
@@ -64,18 +64,18 @@ func (cache *PeerCache) ApplyUpdate(update []byte, router *Router) ([]byte, erro
 	// have no knowledge of. We can now apply the update. Start by
 	// adding in any new peers into the cache.
 	for name, newPeer := range newPeers {
-		cache.table[name] = newPeer
+		peers.table[name] = newPeer
 	}
 
 	// Now apply the updates
-	newUpdate := cache.applyUpdate(decodedUpdate, decodedConns, router)
+	newUpdate := peers.applyUpdate(decodedUpdate, decodedConns, router)
 
-	for _, peerRemoved := range cache.garbageCollect(router.Ourself) {
+	for _, peerRemoved := range peers.garbageCollect(router.Ourself) {
 		delete(newUpdate, peerRemoved.Name)
 	}
 
-	// Don't need to hold cache lock any longer
-	cache.Unlock()
+	// Don't need to hold peers lock any longer
+	peers.Unlock()
 
 	if len(newUpdate) > 0 {
 		router.ConnectionMaker.Refresh()
@@ -84,10 +84,10 @@ func (cache *PeerCache) ApplyUpdate(update []byte, router *Router) ([]byte, erro
 	return encodePeersMap(newUpdate), nil
 }
 
-func (cache *PeerCache) EncodeAllPeers() []byte {
-	cache.RLock()
-	defer cache.RUnlock()
-	return encodePeersMap(cache.table)
+func (peers *Peers) EncodeAllPeers() []byte {
+	peers.RLock()
+	defer peers.RUnlock()
+	return encodePeersMap(peers.table)
 }
 
 func EncodePeers(peers ...*Peer) []byte {
@@ -99,15 +99,15 @@ func EncodePeers(peers ...*Peer) []byte {
 	return buf.Bytes()
 }
 
-func (cache *PeerCache) GarbageCollect(router *Router) []*Peer {
-	cache.Lock()
-	defer cache.Unlock()
-	return cache.garbageCollect(router.Ourself)
+func (peers *Peers) GarbageCollect(router *Router) []*Peer {
+	peers.Lock()
+	defer peers.Unlock()
+	return peers.garbageCollect(router.Ourself)
 }
 
-func (cache *PeerCache) String() string {
+func (peers *Peers) String() string {
 	var buf bytes.Buffer
-	cache.ForEach(func(name PeerName, peer *Peer) {
+	peers.ForEach(func(name PeerName, peer *Peer) {
 		buf.WriteString(fmt.Sprint(peer, "\n"))
 		peer.ForEachConnection(func(remoteName PeerName, conn Connection) {
 			buf.WriteString(fmt.Sprintf("   -> %v [%v]\n", remoteName, conn.RemoteTCPAddr()))
@@ -116,8 +116,8 @@ func (cache *PeerCache) String() string {
 	return buf.String()
 }
 
-func (cache *PeerCache) fetchAlias(peer *Peer) (*Peer, bool) {
-	if existingPeer, found := cache.table[peer.Name]; found {
+func (peers *Peers) fetchAlias(peer *Peer) (*Peer, bool) {
+	if existingPeer, found := peers.table[peer.Name]; found {
 		if existingPeer.UID == peer.UID {
 			existingPeer.IncrementLocalRefCount()
 			return existingPeer, true
@@ -128,13 +128,13 @@ func (cache *PeerCache) fetchAlias(peer *Peer) (*Peer, bool) {
 	return nil, false
 }
 
-func (cache *PeerCache) garbageCollect(ourself *Peer) []*Peer {
+func (peers *Peers) garbageCollect(ourself *Peer) []*Peer {
 	removed := []*Peer{}
-	for name, peer := range cache.table {
+	for name, peer := range peers.table {
 		found, _ := ourself.Routes(peer, false)
 		if !found && !peer.IsLocallyReferenced() {
-			cache.onGC(peer)
-			delete(cache.table, name)
+			peers.onGC(peer)
+			delete(peers.table, name)
 			ourself.Router.Macs.Delete(peer)
 			removed = append(removed, peer)
 		}
@@ -151,7 +151,7 @@ func encodePeersMap(peers map[PeerName]*Peer) []byte {
 	return buf.Bytes()
 }
 
-func (cache *PeerCache) decodeUpdate(update []byte, router *Router) (newPeers map[PeerName]*Peer, decodedUpdate []*Peer, decodedConns [][]byte, err error) {
+func (peers *Peers) decodeUpdate(update []byte, router *Router) (newPeers map[PeerName]*Peer, decodedUpdate []*Peer, decodedConns [][]byte, err error) {
 	newPeers = make(map[PeerName]*Peer)
 	decodedUpdate = []*Peer{}
 	decodedConns = [][]byte{}
@@ -172,7 +172,7 @@ func (cache *PeerCache) decodeUpdate(update []byte, router *Router) (newPeers ma
 		newPeer := NewPeer(name, uid, version, router)
 		decodedUpdate = append(decodedUpdate, newPeer)
 		decodedConns = append(decodedConns, connsBuf)
-		existingPeer, found := cache.table[name]
+		existingPeer, found := peers.table[name]
 		if !found {
 			newPeers[name] = newPeer
 		} else if existingPeer.UID != newPeer.UID {
@@ -188,7 +188,7 @@ func (cache *PeerCache) decodeUpdate(update []byte, router *Router) (newPeers ma
 			if _, found := newPeers[remoteName]; found {
 				return
 			}
-			if _, found := cache.table[remoteName]; found {
+			if _, found := peers.table[remoteName]; found {
 				return
 			}
 			// Update refers to a peer which we have no knowledge
@@ -203,13 +203,13 @@ func (cache *PeerCache) decodeUpdate(update []byte, router *Router) (newPeers ma
 	return
 }
 
-func (cache *PeerCache) applyUpdate(decodedUpdate []*Peer, decodedConns [][]byte, router *Router) map[PeerName]*Peer {
+func (peers *Peers) applyUpdate(decodedUpdate []*Peer, decodedConns [][]byte, router *Router) map[PeerName]*Peer {
 	newUpdate := make(map[PeerName]*Peer)
 	for idx, newPeer := range decodedUpdate {
 		connsBuf := decodedConns[idx]
 		name := newPeer.Name
-		// guaranteed to find peer in the cache.table
-		peer := cache.table[name]
+		// guaranteed to find peer in the peers.table
+		peer := peers.table[name]
 		if peer != newPeer {
 			if peer.Version() > newPeer.Version() {
 				// we know more about this one than the update. If
@@ -237,8 +237,8 @@ func (cache *PeerCache) applyUpdate(decodedUpdate []*Peer, decodedConns [][]byte
 		// No - we know that peer is not ourself, so the only prospect
 		// for an update would be someone else calling
 		// router.Peers.ApplyUpdate. But ApplyUpdate takes the Lock on
-		// the peers cache, so there can be no race here.
-		conns := readConnsMap(peer, connsBuf, cache.table)
+		// the router.Peers, so there can be no race here.
+		conns := readConnsMap(peer, connsBuf, peers.table)
 		peer.SetVersionAndConnections(newPeer.Version(), conns)
 		newUpdate[name] = peer
 	}

router/router.go

@@ -27,7 +27,7 @@ func NewRouter(iface *net.Interface, name PeerName, password []byte, connLimit i
 	router := &Router{
 		Iface:     iface,
 		Macs:      NewMacCache(macMaxAge, onMacExpiry),
-		Peers:     NewPeerCache(onPeerGC),
+		Peers:     NewPeers(onPeerGC),
 		ConnLimit: connLimit,
 		BufSz:     bufSz,
 		LogFrame:  logFrame}

router/types.go

@@ -15,7 +15,7 @@ type Router struct {
 	Ourself            *Peer
 	Iface              *net.Interface
 	Macs               *MacCache
-	Peers              *PeerCache
+	Peers              *Peers
 	UDPListener        *net.UDPConn
 	Routes             *Routes
 	ConnectionMaker    *ConnectionMaker