Implement casemapping

TL;DR: supports for casemapping, now logs are saved in
casemapped/canonical/tolower form
(eg. in the #channel directory instead of #Channel... or something)

== What is casemapping? ==

see <https://modern.ircdocs.horse/#casemapping-parameter>

== Casemapping and multi-upstream ==

Since each upstream does not necessarily use the same casemapping, and
since casemappings cannot coexist [0],

1. soju must also update the database accordingly to upstreams'
   casemapping, otherwise it will end up inconsistent,
2. soju must "normalize" entity names and expose only one casemapping
   that is a subset of all supported casemappings (here, ascii).

[0] On some upstreams, "emersion[m]" and "emersion{m}" refer to the same
user (upstreams that advertise rfc1459 for example), while on others
(upstreams that advertise ascii) they don't.

Once upstream's casemapping is known (default to rfc1459), entity names
in map keys are made into casemapped form, for upstreamConn,
upstreamChannel and network.

downstreamConn advertises "CASEMAPPING=ascii", and always casemap map
keys with ascii.

Some functions require the caller to casemap their argument (to avoid
needless calls to casemapping functions).

== Message forwarding and casemapping ==

downstream message handling (joins and parts basically):
When relaying entity names from downstreams to upstreams, soju uses the
upstream casemapping, in order to not get in the way of the user.  This
does not brings any issue, as long as soju replies with the ascii
casemapping in mind (solves point 1.).

marshalEntity/marshalUserPrefix:
When relaying entity names from upstreams with non-ascii casemappings,
soju *partially* casemap them: it only change the case of characters
which are not ascii letters.  ASCII case is thus kept intact, while
special symbols like []{} are the same every time soju sends them to
downstreams (solves point 2.).

== Casemapping changes ==

Casemapping changes are not fully supported by this patch and will
result in loss of history.  This is a limitation of the protocol and
should be solved by the RENAME spec.

bridge.go

@@ -54,7 +54,9 @@ func sendNames(dc *downstreamConn, ch *upstreamChannel) {
 	maxLength := maxMessageLength - len(emptyNameReply.String())
 
 	var buf strings.Builder
-	for nick, memberships := range ch.Members {
+	for _, entry := range ch.Members.innerMap {
+		nick := entry.originalKey
+		memberships := entry.value.(*memberships)
 		s := memberships.Format(dc) + dc.marshalEntity(ch.conn.network, nick)
 
 		n := buf.Len() + 1 + len(s)

downstream.go

@@ -116,6 +116,7 @@ type downstreamConn struct {
 	registered  bool
 	user        *user
 	nick        string
+	nickCM      string
 	rawUsername string
 	networkName string
 	clientName  string
@@ -192,13 +193,13 @@ func (dc *downstreamConn) upstream() *upstreamConn {
 func isOurNick(net *network, nick string) bool {
 	// TODO: this doesn't account for nick changes
 	if net.conn != nil {
-		return nick == net.conn.nick
+		return net.casemap(nick) == net.conn.nickCM
 	}
 	// We're not currently connected to the upstream connection, so we don't
 	// know whether this name is our nickname. Best-effort: use the network's
 	// configured nickname and hope it was the one being used when we were
 	// connected.
-	return nick == net.Nick
+	return net.casemap(nick) == net.casemap(net.Nick)
 }
 
 // marshalEntity converts an upstream entity name (ie. channel or nick) into a
@@ -210,6 +211,7 @@ func (dc *downstreamConn) marshalEntity(net *network, name string) string {
 	if isOurNick(net, name) {
 		return dc.nick
 	}
+	name = partialCasemap(net.casemap, name)
 	if dc.network != nil {
 		if dc.network != net {
 			panic("soju: tried to marshal an entity for another network")
@@ -223,6 +225,7 @@ func (dc *downstreamConn) marshalUserPrefix(net *network, prefix *irc.Prefix) *i
 	if isOurNick(net, prefix.Name) {
 		return dc.prefix()
 	}
+	prefix.Name = partialCasemap(net.casemap, prefix.Name)
 	if dc.network != nil {
 		if dc.network != net {
 			panic("soju: tried to marshal a user prefix for another network")
@@ -358,8 +361,8 @@ func (dc *downstreamConn) ackMsgID(id string) {
 		return
 	}
 
-	delivered, ok := network.delivered[entity]
+	delivered := network.delivered.Value(entity)
-	if !ok {
+	if delivered == nil {
 		return
 	}
 
@@ -445,13 +448,15 @@ func (dc *downstreamConn) handleMessageUnregistered(msg *irc.Message) error {
 				Params:  []string{dc.nick, nick, "contains illegal characters"},
 			}}
 		}
-		if nick == serviceNick {
+		nickCM := casemapASCII(nick)
+		if nickCM == serviceNickCM {
 			return ircError{&irc.Message{
 				Command: irc.ERR_NICKNAMEINUSE,
 				Params:  []string{dc.nick, nick, "Nickname reserved for bouncer service"},
 			}}
 		}
 		dc.nick = nick
+		dc.nickCM = nickCM
 	case "USER":
 		if err := parseMessageParams(msg, &dc.rawUsername, nil, nil, &dc.realname); err != nil {
 			return err
@@ -766,6 +771,7 @@ func (dc *downstreamConn) updateNick() {
 			Params:  []string{uc.nick},
 		})
 		dc.nick = uc.nick
+		dc.nickCM = casemapASCII(dc.nick)
 	}
 }
 
@@ -911,6 +917,7 @@ func (dc *downstreamConn) welcome() error {
 
 	isupport := []string{
 		fmt.Sprintf("CHATHISTORY=%v", dc.srv.HistoryLimit),
+		"CASEMAPPING=ascii",
 	}
 
 	if uc := dc.upstream(); uc != nil {
@@ -960,11 +967,13 @@ func (dc *downstreamConn) welcome() error {
 	dc.updateSupportedCaps()
 
 	dc.forEachUpstream(func(uc *upstreamConn) {
-		for _, ch := range uc.channels {
+		for _, entry := range uc.channels.innerMap {
+			ch := entry.value.(*upstreamChannel)
 			if !ch.complete {
 				continue
 			}
-			if record, ok := uc.network.channels[ch.Name]; ok && record.Detached {
+			record := uc.network.channels.Value(ch.Name)
+			if record != nil && record.Detached {
 				continue
 			}
 
@@ -987,8 +996,10 @@ func (dc *downstreamConn) welcome() error {
 		}
 
 		// Fast-forward history to last message
-		for target, delivered := range net.delivered {
+		for target, entry := range net.delivered.innerMap {
-			if ch, ok := net.channels[target]; ok && ch.Detached {
+			delivered := entry.value.(map[string]string)
+			ch := net.channels.Value(target)
+			if ch != nil && ch.Detached {
 				continue
 			}
 
@@ -1019,7 +1030,8 @@ func (dc *downstreamConn) messageSupportsHistory(msg *irc.Message) bool {
 }
 
 func (dc *downstreamConn) sendNetworkBacklog(net *network) {
-	for target := range net.delivered {
+	for _, entry := range net.delivered.innerMap {
+		target := entry.originalKey
 		dc.sendTargetBacklog(net, target)
 	}
 }
@@ -1028,11 +1040,11 @@ func (dc *downstreamConn) sendTargetBacklog(net *network, target string) {
 	if dc.caps["draft/chathistory"] || dc.user.msgStore == nil {
 		return
 	}
-	if ch, ok := net.channels[target]; ok && ch.Detached {
+	if ch := net.channels.Value(target); ch != nil && ch.Detached {
 		return
 	}
-	delivered, ok := net.delivered[target]
+	delivered := net.delivered.Value(target)
-	if !ok {
+	if delivered == nil {
 		return
 	}
 	lastDelivered, ok := delivered[dc.clientName]
@@ -1158,7 +1170,7 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 				Params:  []string{dc.nick, rawNick, "contains illegal characters"},
 			}}
 		}
-		if nick == serviceNick {
+		if casemapASCII(nick) == serviceNickCM {
 			return ircError{&irc.Message{
 				Command: irc.ERR_NICKNAMEINUSE,
 				Params:  []string{dc.nick, rawNick, "Nickname reserved for bouncer service"},
@@ -1194,6 +1206,7 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 				Params:  []string{nick},
 			})
 			dc.nick = nick
+			dc.nickCM = casemapASCII(dc.nick)
 		}
 	case "JOIN":
 		var namesStr string
@@ -1226,9 +1239,8 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 				Params:  params,
 			})
 
-			var ch *Channel
+			ch := uc.network.channels.Value(upstreamName)
-			var ok bool
+			if ch != nil {
-			if ch, ok = uc.network.channels[upstreamName]; ok {
 				// Don't clear the channel key if there's one set
 				// TODO: add a way to unset the channel key
 				if key != "" {
@@ -1240,7 +1252,7 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 					Name: upstreamName,
 					Key:  key,
 				}
-				uc.network.channels[upstreamName] = ch
+				uc.network.channels.SetValue(upstreamName, ch)
 			}
 			if err := dc.srv.db.StoreChannel(uc.network.ID, ch); err != nil {
 				dc.logger.Printf("failed to create or update channel %q: %v", upstreamName, err)
@@ -1264,16 +1276,15 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 			}
 
 			if strings.EqualFold(reason, "detach") {
-				var ch *Channel
+				ch := uc.network.channels.Value(upstreamName)
-				var ok bool
+				if ch != nil {
-				if ch, ok = uc.network.channels[upstreamName]; ok {
 					uc.network.detach(ch)
 				} else {
 					ch = &Channel{
 						Name:     name,
 						Detached: true,
 					}
-					uc.network.channels[upstreamName] = ch
+					uc.network.channels.SetValue(upstreamName, ch)
 				}
 				if err := dc.srv.db.StoreChannel(uc.network.ID, ch); err != nil {
 					dc.logger.Printf("failed to create or update channel %q: %v", upstreamName, err)
@@ -1360,7 +1371,7 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 			modeStr = msg.Params[1]
 		}
 
-		if name == dc.nick {
+		if casemapASCII(name) == dc.nickCM {
 			if modeStr != "" {
 				dc.forEachUpstream(func(uc *upstreamConn) {
 					uc.SendMessageLabeled(dc.id, &irc.Message{
@@ -1398,8 +1409,8 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 				Params:  params,
 			})
 		} else {
-			ch, ok := uc.channels[upstreamName]
+			ch := uc.channels.Value(upstreamName)
-			if !ok {
+			if ch == nil {
 				return ircError{&irc.Message{
 					Command: irc.ERR_NOSUCHCHANNEL,
 					Params:  []string{dc.nick, name, "No such channel"},
@@ -1435,7 +1446,7 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 			return err
 		}
 
-		uc, upstreamChannel, err := dc.unmarshalEntity(channel)
+		uc, upstreamName, err := dc.unmarshalEntity(channel)
 		if err != nil {
 			return err
 		}
@@ -1444,14 +1455,14 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 			topic := msg.Params[1]
 			uc.SendMessageLabeled(dc.id, &irc.Message{
 				Command: "TOPIC",
-				Params:  []string{upstreamChannel, topic},
+				Params:  []string{upstreamName, topic},
 			})
 		} else { // getting topic
-			ch, ok := uc.channels[upstreamChannel]
+			ch := uc.channels.Value(upstreamName)
-			if !ok {
+			if ch == nil {
 				return ircError{&irc.Message{
 					Command: irc.ERR_NOSUCHCHANNEL,
-					Params:  []string{dc.nick, upstreamChannel, "No such channel"},
+					Params:  []string{dc.nick, upstreamName, "No such channel"},
 				}}
 			}
 			sendTopic(dc, ch)
@@ -1513,19 +1524,19 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 
 		channels := strings.Split(msg.Params[0], ",")
 		for _, channel := range channels {
-			uc, upstreamChannel, err := dc.unmarshalEntity(channel)
+			uc, upstreamName, err := dc.unmarshalEntity(channel)
 			if err != nil {
 				return err
 			}
 
-			ch, ok := uc.channels[upstreamChannel]
+			ch := uc.channels.Value(upstreamName)
-			if ok {
+			if ch != nil {
 				sendNames(dc, ch)
 			} else {
 				// NAMES on a channel we have not joined, ask upstream
 				uc.SendMessageLabeled(dc.id, &irc.Message{
 					Command: "NAMES",
-					Params:  []string{upstreamChannel},
+					Params:  []string{upstreamName},
 				})
 			}
 		}
@@ -1542,8 +1553,9 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 
 		// TODO: support WHO masks
 		entity := msg.Params[0]
+		entityCM := casemapASCII(entity)
 
-		if entity == dc.nick {
+		if entityCM == dc.nickCM {
 			// TODO: support AWAY (H/G) in self WHO reply
 			dc.SendMessage(&irc.Message{
 				Prefix:  dc.srv.prefix(),
@@ -1557,7 +1569,7 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 			})
 			return nil
 		}
-		if entity == serviceNick {
+		if entityCM == serviceNickCM {
 			dc.SendMessage(&irc.Message{
 				Prefix:  dc.srv.prefix(),
 				Command: irc.RPL_WHOREPLY,
@@ -1608,7 +1620,7 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 			mask = mask[:i]
 		}
 
-		if mask == dc.nick {
+		if casemapASCII(mask) == dc.nickCM {
 			dc.SendMessage(&irc.Message{
 				Prefix:  dc.srv.prefix(),
 				Command: irc.RPL_WHOISUSER,

irc.go

@@ -121,12 +121,13 @@ outer:
 					return nil, fmt.Errorf("malformed modestring %q: missing mode argument for %c%c", modeStr, plusMinus, mode)
 				}
 				member := arguments[nextArgument]
-				if _, ok := ch.Members[member]; ok {
+				m := ch.Members.Value(member)
+				if m != nil {
 					if plusMinus == '+' {
-						ch.Members[member].Add(ch.conn.availableMemberships, membership)
+						m.Add(ch.conn.availableMemberships, membership)
 					} else {
 						// TODO: for upstreams without multi-prefix, query the user modes again
-						ch.Members[member].Remove(membership)
+						m.Remove(membership)
 					}
 				}
 				needMarshaling[nextArgument] = struct{}{}
@@ -418,3 +419,193 @@ func parseCTCPMessage(msg *irc.Message) (cmd string, params string, ok bool) {
 
 	return cmd, params, true
 }
+
+type casemapping func(string) string
+
+func casemapNone(name string) string {
+	return name
+}
+
+// CasemapASCII of name is the canonical representation of name according to the
+// ascii casemapping.
+func casemapASCII(name string) string {
+	var sb strings.Builder
+	sb.Grow(len(name))
+	for _, r := range name {
+		if 'A' <= r && r <= 'Z' {
+			r += 'a' - 'A'
+		}
+		sb.WriteRune(r)
+	}
+	return sb.String()
+}
+
+// casemapRFC1459 of name is the canonical representation of name according to the
+// rfc1459 casemapping.
+func casemapRFC1459(name string) string {
+	var sb strings.Builder
+	sb.Grow(len(name))
+	for _, r := range name {
+		if 'A' <= r && r <= 'Z' {
+			r += 'a' - 'A'
+		} else if r == '{' {
+			r = '['
+		} else if r == '}' {
+			r = ']'
+		} else if r == '\\' {
+			r = '|'
+		} else if r == '~' {
+			r = '^'
+		}
+		sb.WriteRune(r)
+	}
+	return sb.String()
+}
+
+// casemapRFC1459Strict of name is the canonical representation of name
+// according to the rfc1459-strict casemapping.
+func casemapRFC1459Strict(name string) string {
+	var sb strings.Builder
+	sb.Grow(len(name))
+	for _, r := range name {
+		if 'A' <= r && r <= 'Z' {
+			r += 'a' - 'A'
+		} else if r == '{' {
+			r = '['
+		} else if r == '}' {
+			r = ']'
+		} else if r == '\\' {
+			r = '|'
+		}
+		sb.WriteRune(r)
+	}
+	return sb.String()
+}
+
+func parseCasemappingToken(tokenValue string) (casemap casemapping, ok bool) {
+	switch tokenValue {
+	case "ascii":
+		casemap = casemapASCII
+	case "rfc1459":
+		casemap = casemapRFC1459
+	case "rfc1459-strict":
+		casemap = casemapRFC1459Strict
+	default:
+		return nil, false
+	}
+	return casemap, true
+}
+
+func partialCasemap(higher casemapping, name string) string {
+	nameFullyCM := higher(name)
+	var sb strings.Builder
+	sb.Grow(len(name))
+	for i, r := range nameFullyCM {
+		if 'a' <= r && r <= 'z' {
+			r = rune(name[i])
+		}
+		sb.WriteRune(r)
+	}
+	return sb.String()
+}
+
+type casemapMap struct {
+	innerMap map[string]casemapEntry
+	casemap  casemapping
+}
+
+type casemapEntry struct {
+	originalKey string
+	value       interface{}
+}
+
+func newCasemapMap(size int) casemapMap {
+	return casemapMap{
+		innerMap: make(map[string]casemapEntry, size),
+		casemap:  casemapNone,
+	}
+}
+
+func (cm *casemapMap) OriginalKey(name string) (key string, ok bool) {
+	entry, ok := cm.innerMap[cm.casemap(name)]
+	if !ok {
+		return "", false
+	}
+	return entry.originalKey, true
+}
+
+func (cm *casemapMap) Has(name string) bool {
+	_, ok := cm.innerMap[cm.casemap(name)]
+	return ok
+}
+
+func (cm *casemapMap) Len() int {
+	return len(cm.innerMap)
+}
+
+func (cm *casemapMap) SetValue(name string, value interface{}) {
+	nameCM := cm.casemap(name)
+	entry, ok := cm.innerMap[nameCM]
+	if !ok {
+		cm.innerMap[nameCM] = casemapEntry{
+			originalKey: name,
+			value:       value,
+		}
+		return
+	}
+	entry.value = value
+	cm.innerMap[nameCM] = entry
+}
+
+func (cm *casemapMap) Delete(name string) {
+	delete(cm.innerMap, cm.casemap(name))
+}
+
+func (cm *casemapMap) SetCasemapping(newCasemap casemapping) {
+	cm.casemap = newCasemap
+	newInnerMap := make(map[string]casemapEntry, len(cm.innerMap))
+	for _, entry := range cm.innerMap {
+		newInnerMap[cm.casemap(entry.originalKey)] = entry
+	}
+	cm.innerMap = newInnerMap
+}
+
+type upstreamChannelCasemapMap struct{ casemapMap }
+
+func (cm *upstreamChannelCasemapMap) Value(name string) *upstreamChannel {
+	entry, ok := cm.innerMap[cm.casemap(name)]
+	if !ok {
+		return nil
+	}
+	return entry.value.(*upstreamChannel)
+}
+
+type channelCasemapMap struct{ casemapMap }
+
+func (cm *channelCasemapMap) Value(name string) *Channel {
+	entry, ok := cm.innerMap[cm.casemap(name)]
+	if !ok {
+		return nil
+	}
+	return entry.value.(*Channel)
+}
+
+type membershipsCasemapMap struct{ casemapMap }
+
+func (cm *membershipsCasemapMap) Value(name string) *memberships {
+	entry, ok := cm.innerMap[cm.casemap(name)]
+	if !ok {
+		return nil
+	}
+	return entry.value.(*memberships)
+}
+
+type mapStringStringCasemapMap struct{ casemapMap }
+
+func (cm *mapStringStringCasemapMap) Value(name string) map[string]string {
+	entry, ok := cm.innerMap[cm.casemap(name)]
+	if !ok {
+		return nil
+	}
+	return entry.value.(map[string]string)
+}

service.go

@@ -27,6 +27,7 @@ import (
 )
 
 const serviceNick = "BouncerServ"
+const serviceNickCM = "bouncerserv"
 const serviceRealname = "soju bouncer service"
 
 var servicePrefix = &irc.Prefix{
@@ -408,7 +409,7 @@ func handleServiceNetworkStatus(dc *downstreamConn, params []string) error {
 			} else {
 				statuses = append(statuses, "connected")
 			}
-			details = fmt.Sprintf("%v channels", len(uc.channels))
+			details = fmt.Sprintf("%v channels", uc.channels.Len())
 		} else {
 			statuses = append(statuses, "disconnected")
 			if net.lastError != nil {
@@ -768,8 +769,8 @@ func handleServiceChannelUpdate(dc *downstreamConn, params []string) error {
 		return fmt.Errorf("unknown channel %q", name)
 	}
 
-	ch, ok := uc.network.channels[upstreamName]
+	ch := uc.network.channels.Value(upstreamName)
-	if !ok {
+	if ch == nil {
 		return fmt.Errorf("unknown channel %q", name)
 	}
 

upstream.go

@@ -48,7 +48,7 @@ type upstreamChannel struct {
 	Status       channelStatus
 	modes        channelModes
 	creationTime string
-	Members      map[string]*memberships
+	Members      membershipsCasemapMap
 	complete     bool
 	detachTimer  *time.Timer
 }
@@ -86,10 +86,11 @@ type upstreamConn struct {
 
 	registered    bool
 	nick          string
+	nickCM        string
 	username      string
 	realname      string
 	modes         userModes
-	channels      map[string]*upstreamChannel
+	channels      upstreamChannelCasemapMap
 	supportedCaps map[string]string
 	caps          map[string]bool
 	batches       map[string]batch
@@ -99,6 +100,8 @@ type upstreamConn struct {
 	saslClient  sasl.Client
 	saslStarted bool
 
+	casemapIsSet bool
+
 	// set of LIST commands in progress, per downstream
 	pendingLISTDownstreamSet map[uint64]struct{}
 }
@@ -186,7 +189,7 @@ func connectToUpstream(network *network) (*upstreamConn, error) {
 		conn:                     *newConn(network.user.srv, newNetIRCConn(netConn), &options),
 		network:                  network,
 		user:                     network.user,
-		channels:                 make(map[string]*upstreamChannel),
+		channels:                 upstreamChannelCasemapMap{newCasemapMap(0)},
 		supportedCaps:            make(map[string]string),
 		caps:                     make(map[string]bool),
 		batches:                  make(map[string]batch),
@@ -213,8 +216,8 @@ func (uc *upstreamConn) forEachDownstreamByID(id uint64, f func(*downstreamConn)
 }
 
 func (uc *upstreamConn) getChannel(name string) (*upstreamChannel, error) {
-	ch, ok := uc.channels[name]
+	ch := uc.channels.Value(name)
-	if !ok {
+	if ch == nil {
 		return nil, fmt.Errorf("unknown channel %q", name)
 	}
 	return ch, nil
@@ -224,6 +227,10 @@ func (uc *upstreamConn) isChannel(entity string) bool {
 	return strings.ContainsRune(uc.availableChannelTypes, rune(entity[0]))
 }
 
+func (uc *upstreamConn) isOurNick(nick string) bool {
+	return uc.nickCM == uc.network.casemap(nick)
+}
+
 func (uc *upstreamConn) getPendingLIST() *pendingLIST {
 	for _, pl := range uc.user.pendingLISTs {
 		if _, ok := pl.pendingCommands[uc.network.ID]; !ok {
@@ -413,11 +420,12 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			uc.produce("", msg, nil)
 		} else { // regular user message
 			target := entity
-			if target == uc.nick {
+			if uc.isOurNick(target) {
 				target = msg.Prefix.Name
 			}
 
-			if ch, ok := uc.network.channels[target]; ok {
+			ch := uc.network.channels.Value(target)
+			if ch != nil {
 				if ch.Detached {
 					uc.handleDetachedMessage(msg.Prefix.Name, text, ch)
 				}
@@ -590,9 +598,10 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 		uc.registered = true
 		uc.logger.Printf("connection registered")
 
-		if len(uc.network.channels) > 0 {
+		if uc.network.channels.Len() > 0 {
 			var channels, keys []string
-			for _, ch := range uc.network.channels {
+			for _, entry := range uc.network.channels.innerMap {
+				ch := entry.value.(*Channel)
 				channels = append(channels, ch.Name)
 				keys = append(keys, ch.Key)
 			}
@@ -634,6 +643,14 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 
 			var err error
 			switch parameter {
+			case "CASEMAPPING":
+				casemap, ok := parseCasemappingToken(value)
+				if !ok {
+					casemap = casemapRFC1459
+				}
+				uc.network.updateCasemapping(casemap)
+				uc.nickCM = uc.network.casemap(uc.nick)
+				uc.casemapIsSet = true
 			case "CHANMODES":
 				if !negate {
 					err = uc.handleChanModes(value)
@@ -671,6 +688,14 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 				dc.SendMessage(msg)
 			}
 		})
+	case irc.ERR_NOMOTD, irc.RPL_ENDOFMOTD:
+		if !uc.casemapIsSet {
+			// upstream did not send any CASEMAPPING token, thus
+			// we assume it implements the old RFCs with rfc1459.
+			uc.casemapIsSet = true
+			uc.network.updateCasemapping(casemapRFC1459)
+			uc.nickCM = uc.network.casemap(uc.nick)
+		}
 	case "BATCH":
 		var tag string
 		if err := parseMessageParams(msg, &tag); err != nil {
@@ -716,16 +741,19 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 		}
 
 		me := false
-		if msg.Prefix.Name == uc.nick {
+		if uc.isOurNick(msg.Prefix.Name) {
 			uc.logger.Printf("changed nick from %q to %q", uc.nick, newNick)
 			me = true
 			uc.nick = newNick
+			uc.nickCM = uc.network.casemap(uc.nick)
 		}
 
-		for _, ch := range uc.channels {
+		for _, entry := range uc.channels.innerMap {
-			if memberships, ok := ch.Members[msg.Prefix.Name]; ok {
+			ch := entry.value.(*upstreamChannel)
-				delete(ch.Members, msg.Prefix.Name)
+			memberships := ch.Members.Value(msg.Prefix.Name)
-				ch.Members[newNick] = memberships
+			if memberships != nil {
+				ch.Members.Delete(msg.Prefix.Name)
+				ch.Members.SetValue(newNick, memberships)
 				uc.appendLog(ch.Name, msg)
 			}
 		}
@@ -750,13 +778,15 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 		}
 
 		for _, ch := range strings.Split(channels, ",") {
-			if msg.Prefix.Name == uc.nick {
+			if uc.isOurNick(msg.Prefix.Name) {
 				uc.logger.Printf("joined channel %q", ch)
-				uc.channels[ch] = &upstreamChannel{
+				members := membershipsCasemapMap{newCasemapMap(0)}
+				members.casemap = uc.network.casemap
+				uc.channels.SetValue(ch, &upstreamChannel{
 					Name:    ch,
 					conn:    uc,
-					Members: make(map[string]*memberships),
+					Members: members,
-				}
+				})
 				uc.updateChannelAutoDetach(ch)
 
 				uc.SendMessage(&irc.Message{
@@ -768,7 +798,7 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 				if err != nil {
 					return err
 				}
-				ch.Members[msg.Prefix.Name] = &memberships{}
+				ch.Members.SetValue(msg.Prefix.Name, &memberships{})
 			}
 
 			chMsg := msg.Copy()
@@ -786,10 +816,11 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 		}
 
 		for _, ch := range strings.Split(channels, ",") {
-			if msg.Prefix.Name == uc.nick {
+			if uc.isOurNick(msg.Prefix.Name) {
 				uc.logger.Printf("parted channel %q", ch)
-				if uch, ok := uc.channels[ch]; ok {
+				uch := uc.channels.Value(ch)
-					delete(uc.channels, ch)
+				if uch != nil {
+					uc.channels.Delete(ch)
 					uch.updateAutoDetach(0)
 				}
 			} else {
@@ -797,7 +828,7 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 				if err != nil {
 					return err
 				}
-				delete(ch.Members, msg.Prefix.Name)
+				ch.Members.Delete(msg.Prefix.Name)
 			}
 
 			chMsg := msg.Copy()
@@ -814,15 +845,15 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			return err
 		}
 
-		if user == uc.nick {
+		if uc.isOurNick(user) {
 			uc.logger.Printf("kicked from channel %q by %s", channel, msg.Prefix.Name)
-			delete(uc.channels, channel)
+			uc.channels.Delete(channel)
 		} else {
 			ch, err := uc.getChannel(channel)
 			if err != nil {
 				return err
 			}
-			delete(ch.Members, user)
+			ch.Members.Delete(user)
 		}
 
 		uc.produce(channel, msg, nil)
@@ -831,13 +862,14 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			return fmt.Errorf("expected a prefix")
 		}
 
-		if msg.Prefix.Name == uc.nick {
+		if uc.isOurNick(msg.Prefix.Name) {
 			uc.logger.Printf("quit")
 		}
 
-		for _, ch := range uc.channels {
+		for _, entry := range uc.channels.innerMap {
-			if _, ok := ch.Members[msg.Prefix.Name]; ok {
+			ch := entry.value.(*upstreamChannel)
-				delete(ch.Members, msg.Prefix.Name)
+			if ch.Members.Has(msg.Prefix.Name) {
+				ch.Members.Delete(msg.Prefix.Name)
 
 				uc.appendLog(ch.Name, msg)
 			}
@@ -908,7 +940,8 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 
 			uc.appendLog(ch.Name, msg)
 
-			if ch, ok := uc.network.channels[name]; !ok || !ch.Detached {
+			c := uc.network.channels.Value(name)
+			if c == nil || !c.Detached {
 				uc.forEachDownstream(func(dc *downstreamConn) {
 					params := make([]string, len(msg.Params))
 					params[0] = dc.marshalEntity(uc.network, name)
@@ -964,7 +997,8 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			return err
 		}
 		if firstMode {
-			if c, ok := uc.network.channels[channel]; !ok || !c.Detached {
+			c := uc.network.channels.Value(channel)
+			if c == nil || !c.Detached {
 				modeStr, modeParams := ch.modes.Format()
 
 				uc.forEachDownstream(func(dc *downstreamConn) {
@@ -1061,8 +1095,8 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			return err
 		}
 
-		ch, ok := uc.channels[name]
+		ch := uc.channels.Value(name)
-		if !ok {
+		if ch == nil {
 			// NAMES on a channel we have not joined, forward to downstream
 			uc.forEachDownstreamByID(downstreamID, func(dc *downstreamConn) {
 				channel := dc.marshalEntity(uc.network, name)
@@ -1090,7 +1124,7 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 
 		for _, s := range splitSpace(members) {
 			memberships, nick := uc.parseMembershipPrefix(s)
-			ch.Members[nick] = memberships
+			ch.Members.SetValue(nick, memberships)
 		}
 	case irc.RPL_ENDOFNAMES:
 		var name string
@@ -1098,8 +1132,8 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			return err
 		}
 
-		ch, ok := uc.channels[name]
+		ch := uc.channels.Value(name)
-		if !ok {
+		if ch == nil {
 			// NAMES on a channel we have not joined, forward to downstream
 			uc.forEachDownstreamByID(downstreamID, func(dc *downstreamConn) {
 				channel := dc.marshalEntity(uc.network, name)
@@ -1118,7 +1152,8 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 		}
 		ch.complete = true
 
-		if c, ok := uc.network.channels[name]; !ok || !c.Detached {
+		c := uc.network.channels.Value(name)
+		if c == nil || !c.Detached {
 			uc.forEachDownstream(func(dc *downstreamConn) {
 				forwardChannel(dc, ch)
 			})
@@ -1272,7 +1307,7 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			return err
 		}
 
-		weAreInvited := nick == uc.nick
+		weAreInvited := uc.isOurNick(nick)
 
 		uc.forEachDownstream(func(dc *downstreamConn) {
 			if !weAreInvited && !dc.caps["invite-notify"] {
@@ -1395,7 +1430,7 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 		// Ignore
 	case irc.RPL_LUSERCLIENT, irc.RPL_LUSEROP, irc.RPL_LUSERUNKNOWN, irc.RPL_LUSERCHANNELS, irc.RPL_LUSERME:
 		// Ignore
-	case irc.RPL_MOTDSTART, irc.RPL_MOTD, irc.RPL_ENDOFMOTD:
+	case irc.RPL_MOTDSTART, irc.RPL_MOTD:
 		// Ignore
 	case irc.RPL_LISTSTART:
 		// Ignore
@@ -1601,6 +1636,7 @@ func splitSpace(s string) []string {
 
 func (uc *upstreamConn) register() {
 	uc.nick = uc.network.Nick
+	uc.nickCM = uc.network.casemap(uc.nick)
 	uc.username = uc.network.GetUsername()
 	uc.realname = uc.network.GetRealname()
 
@@ -1705,20 +1741,21 @@ func (uc *upstreamConn) appendLog(entity string, msg *irc.Message) (msgID string
 	}
 
 	detached := false
-	if ch, ok := uc.network.channels[entity]; ok {
+	if ch := uc.network.channels.Value(entity); ch != nil {
 		detached = ch.Detached
 	}
 
-	delivered, ok := uc.network.delivered[entity]
+	delivered := uc.network.delivered.Value(entity)
-	if !ok {
+	entityCM := uc.network.casemap(entity)
-		lastID, err := uc.user.msgStore.LastMsgID(uc.network, entity, time.Now())
+	if delivered == nil {
+		lastID, err := uc.user.msgStore.LastMsgID(uc.network, entityCM, time.Now())
 		if err != nil {
 			uc.logger.Printf("failed to log message: failed to get last message ID: %v", err)
 			return ""
 		}
 
 		delivered = make(map[string]string)
-		uc.network.delivered[entity] = delivered
+		uc.network.delivered.SetValue(entity, delivered)
 
 		for clientName, _ := range uc.network.offlineClients {
 			delivered[clientName] = lastID
@@ -1733,7 +1770,7 @@ func (uc *upstreamConn) appendLog(entity string, msg *irc.Message) (msgID string
 		}
 	}
 
-	msgID, err := uc.user.msgStore.Append(uc.network, entity, msg)
+	msgID, err := uc.user.msgStore.Append(uc.network, entityCM, msg)
 	if err != nil {
 		uc.logger.Printf("failed to log message: %v", err)
 		return ""
@@ -1754,7 +1791,8 @@ func (uc *upstreamConn) produce(target string, msg *irc.Message, origin *downstr
 	}
 
 	// Don't forward messages if it's a detached channel
-	if ch, ok := uc.network.channels[target]; ok && ch.Detached {
+	ch := uc.network.channels.Value(target)
+	if ch != nil && ch.Detached {
 		return
 	}
 
@@ -1789,9 +1827,13 @@ func (uc *upstreamConn) updateAway() {
 }
 
 func (uc *upstreamConn) updateChannelAutoDetach(name string) {
-	if uch, ok := uc.channels[name]; ok {
+	uch := uc.channels.Value(name)
-		if ch, ok := uc.network.channels[name]; ok && !ch.Detached {
+	if uch == nil {
+		return
+	}
+	ch := uc.network.channels.Value(name)
+	if ch == nil || ch.Detached {
+		return
+	}
 	uch.updateAutoDetach(ch.DetachAfter)
 }
-	}
-}

user.go

@@ -61,17 +61,18 @@ type network struct {
 	stopped chan struct{}
 
 	conn           *upstreamConn
-	channels       map[string]*Channel
+	channels       channelCasemapMap
-	delivered      map[string]map[string]string // entity -> client name -> msg ID
+	delivered      mapStringStringCasemapMap // entity -> client name -> msg ID
 	offlineClients map[string]struct{}       // indexed by client name
 	lastError      error
+	casemap        casemapping
 }
 
 func newNetwork(user *user, record *Network, channels []Channel) *network {
-	m := make(map[string]*Channel, len(channels))
+	m := channelCasemapMap{newCasemapMap(0)}
 	for _, ch := range channels {
 		ch := ch
-		m[ch.Name] = &ch
+		m.SetValue(ch.Name, &ch)
 	}
 
 	return &network{
@@ -79,8 +80,9 @@ func newNetwork(user *user, record *Network, channels []Channel) *network {
 		user:           user,
 		stopped:        make(chan struct{}),
 		channels:       m,
-		delivered:      make(map[string]map[string]string),
+		delivered:      mapStringStringCasemapMap{newCasemapMap(0)},
 		offlineClients: make(map[string]struct{}),
+		casemap:        casemapRFC1459,
 	}
 }
 
@@ -185,7 +187,8 @@ func (net *network) detach(ch *Channel) {
 	net.user.srv.Logger.Printf("network %q: detaching channel %q", net.GetName(), ch.Name)
 
 	if net.conn != nil {
-		if uch, ok := net.conn.channels[ch.Name]; ok {
+		uch := net.conn.channels.Value(ch.Name)
+		if uch != nil {
 			uch.updateAutoDetach(0)
 		}
 	}
@@ -210,7 +213,7 @@ func (net *network) attach(ch *Channel) {
 
 	var uch *upstreamChannel
 	if net.conn != nil {
-		uch = net.conn.channels[ch.Name]
+		uch = net.conn.channels.Value(ch.Name)
 
 		net.conn.updateChannelAutoDetach(ch.Name)
 	}
@@ -231,12 +234,13 @@ func (net *network) attach(ch *Channel) {
 }
 
 func (net *network) deleteChannel(name string) error {
-	ch, ok := net.channels[name]
+	ch := net.channels.Value(name)
-	if !ok {
+	if ch == nil {
 		return fmt.Errorf("unknown channel %q", name)
 	}
 	if net.conn != nil {
-		if uch, ok := net.conn.channels[ch.Name]; ok {
+		uch := net.conn.channels.Value(ch.Name)
+		if uch != nil {
 			uch.updateAutoDetach(0)
 		}
 	}
@@ -244,10 +248,23 @@ func (net *network) deleteChannel(name string) error {
 	if err := net.user.srv.db.DeleteChannel(ch.ID); err != nil {
 		return err
 	}
-	delete(net.channels, name)
+	net.channels.Delete(name)
 	return nil
 }
 
+func (net *network) updateCasemapping(newCasemap casemapping) {
+	net.casemap = newCasemap
+	net.channels.SetCasemapping(newCasemap)
+	net.delivered.SetCasemapping(newCasemap)
+	if net.conn != nil {
+		net.conn.channels.SetCasemapping(newCasemap)
+		for _, entry := range net.conn.channels.innerMap {
+			uch := entry.value.(*upstreamChannel)
+			uch.Members.SetCasemapping(newCasemap)
+		}
+	}
+}
+
 type user struct {
 	User
 	srv *Server
@@ -410,8 +427,8 @@ func (u *user) run() {
 			}
 		case eventChannelDetach:
 			uc, name := e.uc, e.name
-			c, ok := uc.network.channels[name]
+			c := uc.network.channels.Value(name)
-			if !ok || c.Detached {
+			if c == nil || c.Detached {
 				continue
 			}
 			uc.network.detach(c)
@@ -499,7 +516,8 @@ func (u *user) handleUpstreamDisconnected(uc *upstreamConn) {
 
 	uc.endPendingLISTs(true)
 
-	for _, uch := range uc.channels {
+	for _, entry := range uc.channels.innerMap {
+		uch := entry.value.(*upstreamChannel)
 		uch.updateAutoDetach(0)
 	}
 
@@ -570,8 +588,9 @@ func (u *user) updateNetwork(record *Network) (*network, error) {
 
 	// Most network changes require us to re-connect to the upstream server
 
-	channels := make([]Channel, 0, len(network.channels))
+	channels := make([]Channel, 0, network.channels.Len())
-	for _, ch := range network.channels {
+	for _, entry := range network.channels.innerMap {
+		ch := entry.value.(*Channel)
 		channels = append(channels, *ch)
 	}