internal/poll: remove handle field from Windows' poll.operation

The handle field can be accessed directly wherever needed, there is
no need to store it in the operation struct.

This skims down the size of os.File by 16 bytes.

Change-Id: I87c94cb773437891127b6c36dc7f8883622ffed3
Reviewed-on: https://go-review.googlesource.com/c/go/+/685435
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>
Auto-Submit: Michael Knyszek <[email protected]>
Reviewed-by: Damien Neil <[email protected]>

Author: qmuntal

src/internal/poll/fd_windows.go

@@ -77,15 +77,14 @@ type operation struct {
 	mode       int32
 
 	// fields used only by net package
-	buf    syscall.WSABuf
-	msg    windows.WSAMsg
-	sa     syscall.Sockaddr
-	rsa    *syscall.RawSockaddrAny
-	rsan   int32
-	handle syscall.Handle
-	flags  uint32
-	qty    uint32
-	bufs   []syscall.WSABuf
+	buf   syscall.WSABuf
+	msg   windows.WSAMsg
+	sa    syscall.Sockaddr
+	rsa   *syscall.RawSockaddrAny
+	rsan  int32
+	flags uint32
+	qty   uint32
+	bufs  []syscall.WSABuf
 }
 
 func (o *operation) setEvent() {
@@ -1028,10 +1027,9 @@ func (fd *FD) ConnectEx(ra syscall.Sockaddr) error {
 
 func (fd *FD) acceptOne(s syscall.Handle, rawsa []syscall.RawSockaddrAny, o *operation) (string, error) {
 	// Submit accept request.
-	o.handle = s
 	o.rsan = int32(unsafe.Sizeof(rawsa[0]))
 	_, err := fd.execIO(o, func(o *operation) error {
-		return AcceptFunc(fd.Sysfd, o.handle, (*byte)(unsafe.Pointer(&rawsa[0])), 0, uint32(o.rsan), uint32(o.rsan), &o.qty, &o.o)
+		return AcceptFunc(fd.Sysfd, s, (*byte)(unsafe.Pointer(&rawsa[0])), 0, uint32(o.rsan), uint32(o.rsan), &o.qty, &o.o)
 	})
 	if err != nil {
 		CloseFunc(s)

src/internal/poll/sendfile_windows.go

@@ -63,7 +63,6 @@ func SendFile(fd *FD, src uintptr, size int64) (written int64, err error, handle
 	const maxChunkSizePerCall = int64(0x7fffffff - 1)
 
 	o := &fd.wop
-	o.handle = hsrc
 	for size > 0 {
 		chunkSize := maxChunkSizePerCall
 		if chunkSize > size {
@@ -76,7 +75,7 @@ func SendFile(fd *FD, src uintptr, size int64) (written int64, err error, handle
 
 		n, err := fd.execIO(o, func(o *operation) error {
 			o.qty = uint32(chunkSize)
-			return syscall.TransmitFile(fd.Sysfd, o.handle, o.qty, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
+			return syscall.TransmitFile(fd.Sysfd, hsrc, o.qty, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
 		})
 		if err != nil {
 			return written, err, written > 0