From 2ec9568b10cff8bd82b78e34e9005552134135d6 Mon Sep 17 00:00:00 2001
From: Zhuowei Wang <wangzhuowei@bytedance.com>
Date: Wed, 11 Sep 2024 15:30:27 +0800
Subject: [PATCH] feat: support new connection by fd

---
 net_dialer.go      | 16 ++++++++++++++++
 net_dialer_test.go | 15 +++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/net_dialer.go b/net_dialer.go
index 85f1b7c6..74edd91c 100644
--- a/net_dialer.go
+++ b/net_dialer.go
@@ -28,6 +28,22 @@ func DialConnection(network, address string, timeout time.Duration) (connection
 	return defaultDialer.DialConnection(network, address, timeout)
 }
 
+// NewFDConnection create a Connection initialed by any fd
+// It's useful for write unit test for functions have args with the type of netpoll.Connection
+// The typical usage like:
+//
+//	rfd, wfd := netpoll.GetSysFdPairs()
+//	rconn, _ = netpoll.NewFDConnection(rfd)
+//	wconn, _ = netpoll.NewFDConnection(wfd)
+func NewFDConnection(fd int) (Connection, error) {
+	conn := new(connection)
+	err := conn.init(&netFD{fd: fd}, nil)
+	if err != nil {
+		return nil, err
+	}
+	return conn, nil
+}
+
 // NewDialer only support TCP and unix socket now.
 func NewDialer() Dialer {
 	return &dialer{}
diff --git a/net_dialer_test.go b/net_dialer_test.go
index 64fa50cf..88a16af8 100644
--- a/net_dialer_test.go
+++ b/net_dialer_test.go
@@ -214,6 +214,21 @@ func TestDialerThenClose(t *testing.T) {
 	wg.Wait()
 }
 
+func TestNewFDConnection(t *testing.T) {
+	r, w := GetSysFdPairs()
+	rconn, err := NewFDConnection(r)
+	MustNil(t, err)
+	wconn, err := NewFDConnection(w)
+	MustNil(t, err)
+	_, err = rconn.Writer().WriteString("hello")
+	MustNil(t, err)
+	err = rconn.Writer().Flush()
+	MustNil(t, err)
+	buf, err := wconn.Reader().Next(5)
+	MustNil(t, err)
+	Equal(t, string(buf), "hello")
+}
+
 func mockDialerEventLoop(idx int) EventLoop {
 	el, _ := NewEventLoop(func(ctx context.Context, conn Connection) (err error) {
 		defer func() {