fix: check is active when flush (#118)

connection_impl.go

@@ -205,7 +205,7 @@ func (c *connection) MallocLen() (length int) {
 // If empty, it will call syscall.Write to send data directly,
 // otherwise the buffer will be sent asynchronously by the epoll trigger.
 func (c *connection) Flush() error {
-	if !c.lock(flushing) {
+	if !c.IsActive() || !c.lock(flushing) {
 		return Exception(ErrConnClosed, "when flush")
 	}
 	defer c.unlock(flushing)
@@ -267,7 +267,7 @@ func (c *connection) Read(p []byte) (n int, err error) {
 
 // Write will Flush soon.
 func (c *connection) Write(p []byte) (n int, err error) {
-	if !c.lock(flushing) {
+	if !c.IsActive() || !c.lock(flushing) {
 		return 0, Exception(ErrConnClosed, "when write")
 	}
 	defer c.unlock(flushing)

netpoll_test.go

@@ -245,6 +245,37 @@ func TestCloseCallbackWhenOnConnect(t *testing.T) {
 	MustNil(t, err)
 }
 
+func TestCloseAndWrite(t *testing.T) {
+	var network, address = "tcp", ":18888"
+	var sendMsg = []byte("hello")
+	var loop = newTestEventLoop(network, address,
+		func(ctx context.Context, connection Connection) error {
+			_, err := connection.Reader().Next(len(sendMsg))
+			MustNil(t, err)
+
+			err = connection.Close()
+			MustNil(t, err)
+			return nil
+		},
+	)
+
+	var conn, err = DialConnection(network, address, time.Second)
+	MustNil(t, err)
+	_, err = conn.Writer().WriteBinary(sendMsg)
+	MustNil(t, err)
+	err = conn.Writer().Flush()
+	MustNil(t, err)
+
+	time.Sleep(time.Millisecond * 100) // wait for poller close connection
+	_, err = conn.Writer().WriteBinary(sendMsg)
+	MustNil(t, err)
+	err = conn.Writer().Flush()
+	MustTrue(t, errors.Is(err, ErrConnClosed))
+
+	err = loop.Shutdown(context.Background())
+	MustNil(t, err)
+}
+
 func newTestEventLoop(network, address string, onRequest OnRequest, opts ...Option) EventLoop {
 	var listener, _ = CreateListener(network, address)
 	var eventLoop, _ = NewEventLoop(onRequest, opts...)