try re-enable readv reader on windows

common/buf/readv_reader.go

@@ -142,7 +142,7 @@ func init() {
 	value := platform.NewEnvFlag("v2ray.buf.readv").GetValue(func() string { return defaultFlagValue })
 	switch value {
 	case defaultFlagValue, "auto":
-		if (runtime.GOARCH == "386" || runtime.GOARCH == "amd64" || runtime.GOARCH == "s390x") && (runtime.GOOS == "linux" || runtime.GOOS == "darwin") {
+		if (runtime.GOARCH == "386" || runtime.GOARCH == "amd64" || runtime.GOARCH == "s390x") && (runtime.GOOS == "linux" || runtime.GOOS == "darwin" || runtime.GOOS == "windows") {
 			useReadv = true
 		}
 	case "enable":

common/buf/readv_test.go

@@ -0,0 +1,64 @@
+package buf_test
+
+import (
+	"crypto/rand"
+	"net"
+	"testing"
+
+	"v2ray.com/core/common"
+	. "v2ray.com/core/common/buf"
+	"v2ray.com/core/common/compare"
+	"v2ray.com/core/testing/servers/tcp"
+)
+
+func TestReadvReader(t *testing.T) {
+	tcpServer := &tcp.Server{
+		MsgProcessor: func(b []byte) []byte {
+			return b
+		},
+	}
+	dest, err := tcpServer.Start()
+	common.Must(err)
+	defer tcpServer.Close() // nolint: errcheck
+
+	conn, err := net.Dial("tcp", dest.NetAddr())
+	common.Must(err)
+	defer conn.Close() // nolint: errcheck
+
+	const size = 8192
+	data := make([]byte, 8192)
+	common.Must2(rand.Read(data))
+
+	go func() {
+		writer := NewWriter(conn)
+		var mb MultiBuffer
+		common.Must2(mb.Write(data))
+
+		if err := writer.WriteMultiBuffer(mb); err != nil {
+			t.Fatal("failed to write data: ", err)
+		}
+	}()
+
+	rawConn, err := conn.(*net.TCPConn).SyscallConn()
+	common.Must(err)
+
+	reader := NewReadVReader(conn, rawConn)
+	var rmb MultiBuffer
+	for {
+		mb, err := reader.ReadMultiBuffer()
+		if err != nil {
+			t.Fatal("unexpected error: ", err)
+		}
+		rmb.AppendMulti(mb)
+		if rmb.Len() == size {
+			break
+		}
+	}
+
+	rdata := make([]byte, size)
+	common.Must2(rmb.Read(rdata))
+
+	if err := compare.BytesEqualWithDetail(data, rdata); err != nil {
+		t.Fatal(err)
+	}
+}

common/buf/readv_windows.go

@@ -5,10 +5,7 @@ package buf
 import "syscall"
 
 type windowsReader struct {
-	o     syscall.Overlapped
+	bufs []syscall.WSABuf
-	bufs  []syscall.WSABuf
-	flags uint32
-	qty   uint32
 }
 
 func (r *windowsReader) Init(bs []*Buffer) {
@@ -29,7 +26,9 @@ func (r *windowsReader) Clear() {
 
 func (r *windowsReader) Read(fd uintptr) int32 {
 	var nBytes uint32
-	err := syscall.WSARecv(syscall.Handle(fd), &r.bufs[0], uint32(len(r.bufs)), &nBytes, &r.flags, &r.o, nil)
+	var flags uint32
+	var o syscall.Overlapped
+	err := syscall.WSARecv(syscall.Handle(fd), &r.bufs[0], uint32(len(r.bufs)), &nBytes, &flags, &o, nil)
 	if err != nil {
 		return -1
 	}