libnmdc: use extra variable instead of reflect package

src/libnmdc/libnmdc.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"net"
 	"net/url"
-	"reflect"
 	"regexp"
 	"strings"
 	"time"
@@ -97,20 +96,10 @@ type HubConnection struct {
 
 	// Private state
 	conn         net.Conn // this is an interface
+	connValid    bool
 	sentOurHello bool
 }
 
-func isNil(a interface{}) bool {
-	// Workaround to catch the potential for storing nil in an interface.
-	// @ref http://stackoverflow.com/q/13476349
-	defer func() { recover() }()
-	return a == nil || reflect.ValueOf(a).IsNil()
-}
-
-func (this *HubConnection) isConnValid() bool {
-	return isNil(this.conn)
-}
-
 type HubEvent struct {
 	EventType   HubEventType
 	Nick        string
@@ -174,7 +163,7 @@ func (this *HubConnection) userJoined_Full(uinf *UserInfo) {
 // Note that protocol messages are transmitted on the caller thread, not from
 // any internal libnmdc thread.
 func (this *HubConnection) SayRaw(protocolCommand string) error {
-	if this.isConnValid() {
+	if this.connValid {
 		_, err := this.conn.Write([]byte(protocolCommand))
 		return err
 	} else {
@@ -354,12 +343,14 @@ func (this *HubConnection) worker() {
 
 			if err == nil {
 				this.OnEvent <- HubEvent{EventType: EVENT_CONNECTION_STATE_CHANGED, StateChange: CONNECTIONSTATE_CONNECTING}
-				this.conn = nil // WARNING: storing nil in an interface(!)
+				this.connValid = false
+			} else {
+				this.connValid = true
 			}
 		}
 
 		// Read from socket into our local buffer (blocking)
-		if this.isConnValid() {
+		if this.connValid {
 			readBuff := make([]byte, 4096)
 			nbytes, err = this.conn.Read(readBuff)
 			if nbytes > 0 {