fix race

lib/gsql/client.go

@@ -23,8 +23,8 @@ type Client struct {
 	closed bool
 	mu     sync.Mutex
 
-	readQueue  chan struct{}
-	writeQueue chan struct{}
+	readC  *sync.Cond
+	writeC *sync.Cond
 }
 
 func (T *Client) Do(result ResultWriter, packets ...fed.Packet) {
@@ -36,14 +36,8 @@ func (T *Client) Do(result ResultWriter, packets ...fed.Packet) {
 		packets: packets,
 	})
 
-	if T.readQueue != nil {
-		for {
-			select {
-			case T.readQueue <- struct{}{}:
-			default:
-				return
-			}
-		}
+	if T.readC != nil {
+		T.readC.Broadcast()
 	}
 }
 
@@ -66,13 +60,8 @@ func (T *Client) ReadPacket(typed bool) (fed.Packet, error) {
 				T.read.PushBack(packet)
 			}
 			T.write = b.result
-		outer:
-			for {
-				select {
-				case T.writeQueue <- struct{}{}:
-				default:
-					break outer
-				}
+			if T.writeC != nil {
+				T.writeC.Broadcast()
 			}
 			continue
 		}
@@ -81,17 +70,10 @@ func (T *Client) ReadPacket(typed bool) (fed.Packet, error) {
 			return nil, io.EOF
 		}
 
-		func() {
-			if T.readQueue == nil {
-				T.readQueue = make(chan struct{})
-			}
-			q := T.readQueue
-
-			T.mu.Unlock()
-			defer T.mu.Lock()
-
-			<-q
-		}()
+		if T.readC == nil {
+			T.readC = sync.NewCond(&T.mu)
+		}
+		T.readC.Wait()
 	}
 
 	if (p.Type() == 0 && typed) || (p.Type() != 0 && !typed) {
@@ -110,17 +92,10 @@ func (T *Client) WritePacket(packet fed.Packet) error {
 			return io.EOF
 		}
 
-		func() {
-			if T.writeQueue == nil {
-				T.writeQueue = make(chan struct{})
-			}
-			q := T.writeQueue
-
-			T.mu.Unlock()
-			defer T.mu.Lock()
-
-			<-q
-		}()
+		if T.writeC == nil {
+			T.writeC = sync.NewCond(&T.mu)
+		}
+		T.writeC.Wait()
 	}
 
 	if err := T.write.WritePacket(packet); err != nil {
@@ -140,11 +115,11 @@ func (T *Client) Close() error {
 
 	T.closed = true
 
-	if T.writeQueue != nil {
-		close(T.writeQueue)
+	if T.writeC != nil {
+		T.writeC.Broadcast()
 	}
-	if T.readQueue != nil {
-		close(T.readQueue)
+	if T.readC != nil {
+		T.readC.Broadcast()
 	}
 	return nil
 }