From efb3000717736c014d07b2c06b9ed79489ea39e9 Mon Sep 17 00:00:00 2001
From: Daniel Oaks <daniel@danieloaks.net>
Date: Wed, 11 Jan 2017 01:06:02 +1000
Subject: [PATCH] client_lookup_set: Use RWMutex

---
 irc/client_lookup_set.go | 26 +++++++++++++-------------
 irc/server.go            | 12 ++++++------
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/irc/client_lookup_set.go b/irc/client_lookup_set.go
index 57f01b58..1437624f 100644
--- a/irc/client_lookup_set.go
+++ b/irc/client_lookup_set.go
@@ -36,7 +36,7 @@ func ExpandUserHost(userhost string) (expanded string) {
 }
 
 type ClientLookupSet struct {
-	ByNickMutex sync.Mutex
+	ByNickMutex sync.RWMutex
 	ByNick      map[string]*Client
 }
 
@@ -47,8 +47,8 @@ func NewClientLookupSet() *ClientLookupSet {
 }
 
 func (clients *ClientLookupSet) Count() int {
-	clients.ByNickMutex.Lock()
-	defer clients.ByNickMutex.Unlock()
+	clients.ByNickMutex.RLock()
+	defer clients.ByNickMutex.RUnlock()
 	count := len(clients.ByNick)
 	return count
 }
@@ -59,8 +59,8 @@ func (clients *ClientLookupSet) Has(nick string) bool {
 	if err == nil {
 		return false
 	}
-	clients.ByNickMutex.Lock()
-	defer clients.ByNickMutex.Unlock()
+	clients.ByNickMutex.RLock()
+	defer clients.ByNickMutex.RUnlock()
 	_, exists := clients.ByNick[casefoldedName]
 	return exists
 }
@@ -78,8 +78,8 @@ func (clients *ClientLookupSet) getNoMutex(nick string) *Client {
 func (clients *ClientLookupSet) Get(nick string) *Client {
 	casefoldedName, err := CasefoldName(nick)
 	if err == nil {
-		clients.ByNickMutex.Lock()
-		defer clients.ByNickMutex.Unlock()
+		clients.ByNickMutex.RLock()
+		defer clients.ByNickMutex.RUnlock()
 		cli := clients.ByNick[casefoldedName]
 		return cli
 	}
@@ -149,8 +149,8 @@ func (clients *ClientLookupSet) Replace(oldNick, newNick string, client *Client)
 func (clients *ClientLookupSet) AllWithCaps(caps ...Capability) (set ClientSet) {
 	set = make(ClientSet)
 
-	clients.ByNickMutex.Lock()
-	defer clients.ByNickMutex.Unlock()
+	clients.ByNickMutex.RLock()
+	defer clients.ByNickMutex.RUnlock()
 	var client *Client
 	for _, client = range clients.ByNick {
 		// make sure they have all the required caps
@@ -175,8 +175,8 @@ func (clients *ClientLookupSet) FindAll(userhost string) (set ClientSet) {
 	}
 	matcher := ircmatch.MakeMatch(userhost)
 
-	clients.ByNickMutex.Lock()
-	defer clients.ByNickMutex.Unlock()
+	clients.ByNickMutex.RLock()
+	defer clients.ByNickMutex.RUnlock()
 	for _, client := range clients.ByNick {
 		if matcher.Match(client.nickMaskCasefolded) {
 			set.Add(client)
@@ -194,8 +194,8 @@ func (clients *ClientLookupSet) Find(userhost string) *Client {
 	matcher := ircmatch.MakeMatch(userhost)
 	var matchedClient *Client
 
-	clients.ByNickMutex.Lock()
-	defer clients.ByNickMutex.Unlock()
+	clients.ByNickMutex.RLock()
+	defer clients.ByNickMutex.RUnlock()
 	for _, client := range clients.ByNick {
 		if matcher.Match(client.nickMaskCasefolded) {
 			matchedClient = client
diff --git a/irc/server.go b/irc/server.go
index d9a04f09..d472a454 100644
--- a/irc/server.go
+++ b/irc/server.go
@@ -343,11 +343,11 @@ func loadChannelList(channel *Channel, list string, maskMode ChannelMode) {
 
 func (server *Server) Shutdown() {
 	//TODO(dan): Make sure we disallow new nicks
-	server.clients.ByNickMutex.Lock()
+	server.clients.ByNickMutex.RLock()
 	for _, client := range server.clients.ByNick {
 		client.Notice("Server is shutting down")
 	}
-	server.clients.ByNickMutex.Unlock()
+	server.clients.ByNickMutex.RUnlock()
 
 	if err := server.store.Close(); err != nil {
 		Log.error.Println("Server.Shutdown store.Close: error:", err)
@@ -1069,14 +1069,14 @@ func (server *Server) rehash() error {
 	server.connectionLimitsMutex.Lock()
 	server.connectionLimits = connectionLimits
 
-	server.clients.ByNickMutex.Lock()
+	server.clients.ByNickMutex.RLock()
 	for _, client := range server.clients.ByNick {
 		ipaddr := net.ParseIP(IPString(client.socket.conn.RemoteAddr()))
 		if ipaddr != nil {
 			server.connectionLimits.AddClient(ipaddr, true)
 		}
 	}
-	server.clients.ByNickMutex.Unlock()
+	server.clients.ByNickMutex.RUnlock()
 	server.connectionLimitsMutex.Unlock()
 
 	// setup new and removed caps
@@ -1143,14 +1143,14 @@ func (server *Server) rehash() error {
 	newISupportReplies := oldISupportList.GetDifference(server.isupport)
 
 	// push new info to all of our clients
-	server.clients.ByNickMutex.Lock()
+	server.clients.ByNickMutex.RLock()
 	for _, sClient := range server.clients.ByNick {
 		for _, tokenline := range newISupportReplies {
 			// ugly trickery ahead
 			sClient.Send(nil, server.name, RPL_ISUPPORT, append([]string{sClient.nick}, tokenline...)...)
 		}
 	}
-	server.clients.ByNickMutex.Unlock()
+	server.clients.ByNickMutex.RUnlock()
 
 	// destroy old listeners
 	tlsListeners := config.TLSListeners()