fix #52

Fix data race on (*Connection).batchNegotiated

ircevent/irc.go

@@ -134,7 +134,7 @@ func (irc *Connection) readLoop() {
 			return
 		}
 
-		if irc.batchNegotiated && time.Since(lastExpireCheck) > irc.Timeout {
+		if irc.batchNegotiated() && time.Since(lastExpireCheck) > irc.Timeout {
 			irc.expireBatches(false)
 			lastExpireCheck = time.Now()
 		}
@@ -376,7 +376,7 @@ func (irc *Connection) Send(command string, params ...string) error {
 // If the server fails to respond correctly, the callback will be invoked with `nil`
 // as the argument.
 func (irc *Connection) SendWithLabel(callback func(*Batch), tags map[string]string, command string, params ...string) error {
-	if !irc.labelNegotiated {
+	if !irc.labelNegotiated() {
 		return CapabilityNotNegotiated
 	}
 
@@ -691,14 +691,7 @@ func (irc *Connection) negotiateCaps() error {
 
 	var acknowledgedCaps []string
 	defer func() {
-		irc.stateMutex.Lock()
-		defer irc.stateMutex.Unlock()
-		for _, c := range acknowledgedCaps {
-			irc.capsAcked[c] = irc.capsAdvertised[c]
-		}
-		_, irc.batchNegotiated = irc.capsAcked["batch"]
-		_, labelNegotiated := irc.capsAcked["labeled-response"]
-		irc.labelNegotiated = irc.batchNegotiated && labelNegotiated
+		irc.processAckedCaps(acknowledgedCaps)
 	}()
 
 	irc.Send("CAP", "LS", "302")

ircevent/irc_callback.go

@@ -325,7 +325,7 @@ func (irc *Connection) runCallbacks(msg ircmsg.Message) {
 	}
 
 	// handle batch start or end
-	if irc.batchNegotiated {
+	if irc.batchNegotiated() {
 		if msg.Command == "BATCH" {
 			irc.handleBatchCommand(msg)
 			return
@@ -336,7 +336,7 @@ func (irc *Connection) runCallbacks(msg ircmsg.Message) {
 	}
 
 	// handle labeled single command, or labeled ACK
-	if irc.labelNegotiated {
+	if irc.labelNegotiated() {
 		if hasLabel, labelStr := msg.GetTag("label"); hasLabel {
 			var labelCallback LabelCallback
 			if label := deserializeLabel(labelStr); label != 0 {

ircevent/irc_struct.go

@@ -10,6 +10,7 @@ import (
 	"net"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/goshuirc/irc-go/ircmsg"
@@ -86,11 +87,10 @@ type Connection struct {
 	// Connect() builds these with sufficient capacity to receive all expected
 	// responses during negotiation. Sends to them are nonblocking, so anything
 	// sent outside of negotiation will not cause the relevant callbacks to block.
-	welcomeChan     chan empty      // signals that we got 001 and we are now connected
-	saslChan        chan saslResult // transmits the final outcome of SASL negotiation
-	capsChan        chan capResult  // transmits the final status of each CAP negotiated
-	batchNegotiated bool
-	labelNegotiated bool
+	welcomeChan chan empty      // signals that we got 001 and we are now connected
+	saslChan    chan saslResult // transmits the final outcome of SASL negotiation
+	capsChan    chan capResult  // transmits the final status of each CAP negotiated
+	capFlags    uint32
 
 	// callback state
 	eventsMutex sync.Mutex
@@ -140,6 +140,56 @@ type Batch struct {
 	Items []*Batch
 }
 
+const (
+	capFlagBatch uint32 = 1 << iota
+	capFlagMessageTags
+	capFlagLabeledResponse
+	capFlagMultiline
+)
+
+func (irc *Connection) processAckedCaps(acknowledgedCaps []string) {
+	irc.stateMutex.Lock()
+	defer irc.stateMutex.Unlock()
+	var hasBatch, hasLabel, hasTags, hasMultiline bool
+	for _, c := range acknowledgedCaps {
+		irc.capsAcked[c] = irc.capsAdvertised[c]
+		switch c {
+		case "batch":
+			hasBatch = true
+		case "labeled-response":
+			hasLabel = true
+		case "message-tags":
+			hasTags = true
+		case "draft/multiline", "multiline":
+			hasMultiline = true
+		}
+	}
+
+	var capFlags uint32
+	if hasBatch {
+		capFlags |= capFlagBatch
+	}
+	if hasBatch && hasLabel {
+		capFlags |= capFlagLabeledResponse
+	}
+	if hasTags {
+		capFlags |= capFlagMessageTags
+	}
+	if hasTags && hasBatch && hasMultiline {
+		capFlags |= capFlagMultiline
+	}
+
+	atomic.StoreUint32(&irc.capFlags, capFlags)
+}
+
+func (irc *Connection) batchNegotiated() bool {
+	return atomic.LoadUint32(&irc.capFlags)&capFlagBatch != 0
+}
+
+func (irc *Connection) labelNegotiated() bool {
+	return atomic.LoadUint32(&irc.capFlags)&capFlagLabeledResponse != 0
+}
+
 func ExtractNick(source string) string {
 	nick, _, _ := SplitNUH(source)
 	return nick