internal/poll: remove qty and flags fields from Windows' poll.operation

There is no need to keep the qty and flags fields in the poll.operation
struct.

This skims down the size of os.File by 16 bytes and makes poll.operation
harder to misuse.

Change-Id: I8943d88f29ed3c7eefbb83114b0d31052abbe646
Reviewed-on: https://go-review.googlesource.com/c/go/+/685436
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Mark Freeman <mark@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

diff --git a/src/internal/poll/fd_windows.go b/src/internal/poll/fd_windows.go
index 38fecb0e12db0fcec67cba3b2b06e15b04581efc..1ede48103bc7c6d7307a8d3a3ebbbf1fafab0231 100644 (file)
--- a/src/internal/poll/fd_windows.go
+++ b/src/internal/poll/fd_windows.go
@@ -77,14 +77,12 @@ 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
-       flags uint32
-       qty   uint32
-       bufs  []syscall.WSABuf
+       buf  syscall.WSABuf
+       msg  windows.WSAMsg
+       sa   syscall.Sockaddr
+       rsa  *syscall.RawSockaddrAny
+       rsan int32
+       bufs []syscall.WSABuf
 }
 
 func (o *operation) setEvent() {
@@ -210,7 +208,7 @@ func (fd *FD) cancelIO(o *operation) {
 // It supports both synchronous and asynchronous IO.
 // o.qty and o.flags are set to zero before calling submit
 // to avoid reusing the values from a previous call.
-func (fd *FD) execIO(o *operation, submit func(o *operation) error) (int, error) {
+func (fd *FD) execIO(o *operation, submit func(o *operation) (uint32, error)) (int, error) {
        // Notify runtime netpoll about starting IO.
        err := fd.pd.prepare(int(o.mode), fd.isFile)
        if err != nil {
@@ -223,9 +221,7 @@ func (fd *FD) execIO(o *operation, submit func(o *operation) error) (int, error)
                // event to wait for the IO to complete.
                o.setEvent()
        }
-       o.qty = 0
-       o.flags = 0
-       err = submit(o)
+       qty, err := submit(o)
        var waitErr error
        // Blocking operations shouldn't return ERROR_IO_PENDING.
        // Continue without waiting if that happens.
@@ -240,9 +236,10 @@ func (fd *FD) execIO(o *operation, submit func(o *operation) error) (int, error)
                        // before the cancellation request runs.
                }
                if fd.isFile {
-                       err = windows.GetOverlappedResult(fd.Sysfd, &o.o, &o.qty, false)
+                       err = windows.GetOverlappedResult(fd.Sysfd, &o.o, &qty, false)
                } else {
-                       err = windows.WSAGetOverlappedResult(fd.Sysfd, &o.o, &o.qty, false, &o.flags)
+                       var flags uint32
+                       err = windows.WSAGetOverlappedResult(fd.Sysfd, &o.o, &qty, false, &flags)
                }
        }
        switch err {
@@ -266,7 +263,7 @@ func (fd *FD) execIO(o *operation, submit func(o *operation) error) (int, error)
                        err = waitErr
                }
        }
-       return int(o.qty), err
+       return int(qty), err
 }
 
 // FD is a file descriptor. The net and os packages embed this type in
@@ -507,8 +504,9 @@ func (fd *FD) Read(buf []byte) (int, error) {
        case kindFile, kindPipe:
                o := &fd.rop
                o.InitBuf(buf)
-               n, err = fd.execIO(o, func(o *operation) error {
-                       return syscall.ReadFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &o.qty, fd.overlapped(o))
+               n, err = fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                       err = syscall.ReadFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &qty, fd.overlapped(o))
+                       return qty, err
                })
                fd.addOffset(n)
                switch err {
@@ -523,8 +521,10 @@ func (fd *FD) Read(buf []byte) (int, error) {
        case kindNet:
                o := &fd.rop
                o.InitBuf(buf)
-               n, err = fd.execIO(o, func(o *operation) error {
-                       return syscall.WSARecv(fd.Sysfd, &o.buf, 1, &o.qty, &o.flags, &o.o, nil)
+               n, err = fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                       var flags uint32
+                       err = syscall.WSARecv(fd.Sysfd, &o.buf, 1, &qty, &flags, &o.o, nil)
+                       return qty, err
                })
                if race.Enabled {
                        race.Acquire(unsafe.Pointer(&ioSync))
@@ -638,8 +638,9 @@ func (fd *FD) Pread(b []byte, off int64) (int, error) {
        o := &fd.rop
        o.InitBuf(b)
        fd.setOffset(off)
-       n, err := fd.execIO(o, func(o *operation) error {
-               return syscall.ReadFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &o.qty, &o.o)
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+               err = syscall.ReadFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &qty, &o.o)
+               return qty, err
        })
        if err == syscall.ERROR_HANDLE_EOF {
                err = io.EOF
@@ -664,12 +665,14 @@ func (fd *FD) ReadFrom(buf []byte) (int, syscall.Sockaddr, error) {
        defer fd.readUnlock()
        o := &fd.rop
        o.InitBuf(buf)
-       n, err := fd.execIO(o, func(o *operation) error {
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
                if o.rsa == nil {
                        o.rsa = new(syscall.RawSockaddrAny)
                }
                o.rsan = int32(unsafe.Sizeof(*o.rsa))
-               return syscall.WSARecvFrom(fd.Sysfd, &o.buf, 1, &o.qty, &o.flags, o.rsa, &o.rsan, &o.o, nil)
+               var flags uint32
+               err = syscall.WSARecvFrom(fd.Sysfd, &o.buf, 1, &qty, &flags, o.rsa, &o.rsan, &o.o, nil)
+               return qty, err
        })
        err = fd.eofError(n, err)
        if err != nil {
@@ -693,12 +696,14 @@ func (fd *FD) ReadFromInet4(buf []byte, sa4 *syscall.SockaddrInet4) (int, error)
        defer fd.readUnlock()
        o := &fd.rop
        o.InitBuf(buf)
-       n, err := fd.execIO(o, func(o *operation) error {
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
                if o.rsa == nil {
                        o.rsa = new(syscall.RawSockaddrAny)
                }
                o.rsan = int32(unsafe.Sizeof(*o.rsa))
-               return syscall.WSARecvFrom(fd.Sysfd, &o.buf, 1, &o.qty, &o.flags, o.rsa, &o.rsan, &o.o, nil)
+               var flags uint32
+               err = syscall.WSARecvFrom(fd.Sysfd, &o.buf, 1, &qty, &flags, o.rsa, &o.rsan, &o.o, nil)
+               return qty, err
        })
        err = fd.eofError(n, err)
        if err != nil {
@@ -722,12 +727,14 @@ func (fd *FD) ReadFromInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error)
        defer fd.readUnlock()
        o := &fd.rop
        o.InitBuf(buf)
-       n, err := fd.execIO(o, func(o *operation) error {
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
                if o.rsa == nil {
                        o.rsa = new(syscall.RawSockaddrAny)
                }
                o.rsan = int32(unsafe.Sizeof(*o.rsa))
-               return syscall.WSARecvFrom(fd.Sysfd, &o.buf, 1, &o.qty, &o.flags, o.rsa, &o.rsan, &o.o, nil)
+               var flags uint32
+               err = syscall.WSARecvFrom(fd.Sysfd, &o.buf, 1, &qty, &flags, o.rsa, &o.rsan, &o.o, nil)
+               return qty, err
        })
        err = fd.eofError(n, err)
        if err != nil {
@@ -763,8 +770,9 @@ func (fd *FD) Write(buf []byte) (int, error) {
                case kindPipe, kindFile:
                        o := &fd.wop
                        o.InitBuf(b)
-                       n, err = fd.execIO(o, func(o *operation) error {
-                               return syscall.WriteFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &o.qty, fd.overlapped(o))
+                       n, err = fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                               err = syscall.WriteFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &qty, fd.overlapped(o))
+                               return qty, err
                        })
                        fd.addOffset(n)
                case kindNet:
@@ -773,8 +781,9 @@ func (fd *FD) Write(buf []byte) (int, error) {
                        }
                        o := &fd.wop
                        o.InitBuf(b)
-                       n, err = fd.execIO(o, func(o *operation) error {
-                               return syscall.WSASend(fd.Sysfd, &o.buf, 1, &o.qty, 0, &o.o, nil)
+                       n, err = fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                               err = syscall.WSASend(fd.Sysfd, &o.buf, 1, &qty, 0, &o.o, nil)
+                               return qty, err
                        })
                }
                ntotal += n
@@ -862,8 +871,9 @@ func (fd *FD) Pwrite(buf []byte, off int64) (int, error) {
                o := &fd.wop
                o.InitBuf(b)
                fd.setOffset(off + int64(ntotal))
-               n, err := fd.execIO(o, func(o *operation) error {
-                       return syscall.WriteFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &o.qty, &o.o)
+               n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                       err = syscall.WriteFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &qty, &o.o)
+                       return qty, err
                })
                if n > 0 {
                        ntotal += n
@@ -891,8 +901,9 @@ func (fd *FD) Writev(buf *[][]byte) (int64, error) {
        }
        o := &fd.wop
        o.InitBufs(buf)
-       n, err := fd.execIO(o, func(o *operation) error {
-               return syscall.WSASend(fd.Sysfd, &o.bufs[0], uint32(len(o.bufs)), &o.qty, 0, &o.o, nil)
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+               err = syscall.WSASend(fd.Sysfd, &o.bufs[0], uint32(len(o.bufs)), &qty, 0, &o.o, nil)
+               return qty, err
        })
        o.ClearBufs()
        TestHookDidWritev(n)
@@ -912,8 +923,9 @@ func (fd *FD) WriteTo(buf []byte, sa syscall.Sockaddr) (int, error) {
                o := &fd.wop
                o.InitBuf(buf)
                o.sa = sa
-               n, err := fd.execIO(o, func(o *operation) error {
-                       return syscall.WSASendto(fd.Sysfd, &o.buf, 1, &o.qty, 0, o.sa, &o.o, nil)
+               n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                       err = syscall.WSASendto(fd.Sysfd, &o.buf, 1, &qty, 0, o.sa, &o.o, nil)
+                       return qty, err
                })
                return n, err
        }
@@ -927,8 +939,9 @@ func (fd *FD) WriteTo(buf []byte, sa syscall.Sockaddr) (int, error) {
                o := &fd.wop
                o.InitBuf(b)
                o.sa = sa
-               n, err := fd.execIO(o, func(o *operation) error {
-                       return syscall.WSASendto(fd.Sysfd, &o.buf, 1, &o.qty, 0, o.sa, &o.o, nil)
+               n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                       err = syscall.WSASendto(fd.Sysfd, &o.buf, 1, &qty, 0, o.sa, &o.o, nil)
+                       return qty, err
                })
                ntotal += int(n)
                if err != nil {
@@ -950,8 +963,9 @@ func (fd *FD) WriteToInet4(buf []byte, sa4 *syscall.SockaddrInet4) (int, error)
                // handle zero-byte payload
                o := &fd.wop
                o.InitBuf(buf)
-               n, err := fd.execIO(o, func(o *operation) error {
-                       return windows.WSASendtoInet4(fd.Sysfd, &o.buf, 1, &o.qty, 0, sa4, &o.o, nil)
+               n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                       err = windows.WSASendtoInet4(fd.Sysfd, &o.buf, 1, &qty, 0, sa4, &o.o, nil)
+                       return qty, err
                })
                return n, err
        }
@@ -964,8 +978,9 @@ func (fd *FD) WriteToInet4(buf []byte, sa4 *syscall.SockaddrInet4) (int, error)
                }
                o := &fd.wop
                o.InitBuf(b)
-               n, err := fd.execIO(o, func(o *operation) error {
-                       return windows.WSASendtoInet4(fd.Sysfd, &o.buf, 1, &o.qty, 0, sa4, &o.o, nil)
+               n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                       err = windows.WSASendtoInet4(fd.Sysfd, &o.buf, 1, &qty, 0, sa4, &o.o, nil)
+                       return qty, err
                })
                ntotal += int(n)
                if err != nil {
@@ -987,8 +1002,9 @@ func (fd *FD) WriteToInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error)
                // handle zero-byte payload
                o := &fd.wop
                o.InitBuf(buf)
-               n, err := fd.execIO(o, func(o *operation) error {
-                       return windows.WSASendtoInet6(fd.Sysfd, &o.buf, 1, &o.qty, 0, sa6, &o.o, nil)
+               n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                       err = windows.WSASendtoInet6(fd.Sysfd, &o.buf, 1, &qty, 0, sa6, &o.o, nil)
+                       return qty, err
                })
                return n, err
        }
@@ -1001,8 +1017,9 @@ func (fd *FD) WriteToInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error)
                }
                o := &fd.wop
                o.InitBuf(b)
-               n, err := fd.execIO(o, func(o *operation) error {
-                       return windows.WSASendtoInet6(fd.Sysfd, &o.buf, 1, &o.qty, 0, sa6, &o.o, nil)
+               n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                       err = windows.WSASendtoInet6(fd.Sysfd, &o.buf, 1, &qty, 0, sa6, &o.o, nil)
+                       return qty, err
                })
                ntotal += int(n)
                if err != nil {
@@ -1019,8 +1036,8 @@ func (fd *FD) WriteToInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error)
 func (fd *FD) ConnectEx(ra syscall.Sockaddr) error {
        o := &fd.wop
        o.sa = ra
-       _, err := fd.execIO(o, func(o *operation) error {
-               return ConnectExFunc(fd.Sysfd, o.sa, nil, 0, nil, &o.o)
+       _, err := fd.execIO(o, func(o *operation) (uint32, error) {
+               return 0, ConnectExFunc(fd.Sysfd, o.sa, nil, 0, nil, &o.o)
        })
        return err
 }
@@ -1028,8 +1045,9 @@ 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.rsan = int32(unsafe.Sizeof(rawsa[0]))
-       _, err := fd.execIO(o, func(o *operation) error {
-               return AcceptFunc(fd.Sysfd, s, (*byte)(unsafe.Pointer(&rawsa[0])), 0, uint32(o.rsan), uint32(o.rsan), &o.qty, &o.o)
+       _, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+               err = AcceptFunc(fd.Sysfd, s, (*byte)(unsafe.Pointer(&rawsa[0])), 0, uint32(o.rsan), uint32(o.rsan), &qty, &o.o)
+               return qty, err
        })
        if err != nil {
                CloseFunc(s)
@@ -1171,11 +1189,13 @@ func (fd *FD) RawRead(f func(uintptr) bool) error {
                // socket is readable. h/t https://stackoverflow.com/a/42019668/332798
                o := &fd.rop
                o.InitBuf(nil)
-               _, err := fd.execIO(o, func(o *operation) error {
+               _, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+                       var flags uint32
                        if !fd.IsStream {
-                               o.flags |= windows.MSG_PEEK
+                               flags |= windows.MSG_PEEK
                        }
-                       return syscall.WSARecv(fd.Sysfd, &o.buf, 1, &o.qty, &o.flags, &o.o, nil)
+                       err = syscall.WSARecv(fd.Sysfd, &o.buf, 1, &qty, &flags, &o.o, nil)
+                       return qty, err
                })
                if err == windows.WSAEMSGSIZE {
                        // expected with a 0-byte peek, ignore.
@@ -1270,8 +1290,9 @@ func (fd *FD) ReadMsg(p []byte, oob []byte, flags int) (int, int, int, syscall.S
        o.msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
        o.msg.Namelen = int32(unsafe.Sizeof(*o.rsa))
        o.msg.Flags = uint32(flags)
-       n, err := fd.execIO(o, func(o *operation) error {
-               return windows.WSARecvMsg(fd.Sysfd, &o.msg, &o.qty, &o.o, nil)
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+               err = windows.WSARecvMsg(fd.Sysfd, &o.msg, &qty, &o.o, nil)
+               return qty, err
        })
        err = fd.eofError(n, err)
        var sa syscall.Sockaddr
@@ -1300,8 +1321,9 @@ func (fd *FD) ReadMsgInet4(p []byte, oob []byte, flags int, sa4 *syscall.Sockadd
        o.msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
        o.msg.Namelen = int32(unsafe.Sizeof(*o.rsa))
        o.msg.Flags = uint32(flags)
-       n, err := fd.execIO(o, func(o *operation) error {
-               return windows.WSARecvMsg(fd.Sysfd, &o.msg, &o.qty, &o.o, nil)
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+               err = windows.WSARecvMsg(fd.Sysfd, &o.msg, &qty, &o.o, nil)
+               return qty, err
        })
        err = fd.eofError(n, err)
        if err == nil {
@@ -1329,8 +1351,9 @@ func (fd *FD) ReadMsgInet6(p []byte, oob []byte, flags int, sa6 *syscall.Sockadd
        o.msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
        o.msg.Namelen = int32(unsafe.Sizeof(*o.rsa))
        o.msg.Flags = uint32(flags)
-       n, err := fd.execIO(o, func(o *operation) error {
-               return windows.WSARecvMsg(fd.Sysfd, &o.msg, &o.qty, &o.o, nil)
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+               err = windows.WSARecvMsg(fd.Sysfd, &o.msg, &qty, &o.o, nil)
+               return qty, err
        })
        err = fd.eofError(n, err)
        if err == nil {
@@ -1363,8 +1386,9 @@ func (fd *FD) WriteMsg(p []byte, oob []byte, sa syscall.Sockaddr) (int, int, err
                o.msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
                o.msg.Namelen = len
        }
-       n, err := fd.execIO(o, func(o *operation) error {
-               return windows.WSASendMsg(fd.Sysfd, &o.msg, 0, &o.qty, &o.o, nil)
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+               err = windows.WSASendMsg(fd.Sysfd, &o.msg, 0, nil, &o.o, nil)
+               return qty, err
        })
        return n, int(o.msg.Control.Len), err
 }
@@ -1388,8 +1412,9 @@ func (fd *FD) WriteMsgInet4(p []byte, oob []byte, sa *syscall.SockaddrInet4) (in
        len := sockaddrInet4ToRaw(o.rsa, sa)
        o.msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
        o.msg.Namelen = len
-       n, err := fd.execIO(o, func(o *operation) error {
-               return windows.WSASendMsg(fd.Sysfd, &o.msg, 0, &o.qty, &o.o, nil)
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+               err = windows.WSASendMsg(fd.Sysfd, &o.msg, 0, nil, &o.o, nil)
+               return qty, err
        })
        return n, int(o.msg.Control.Len), err
 }
@@ -1413,8 +1438,9 @@ func (fd *FD) WriteMsgInet6(p []byte, oob []byte, sa *syscall.SockaddrInet6) (in
        len := sockaddrInet6ToRaw(o.rsa, sa)
        o.msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
        o.msg.Namelen = len
-       n, err := fd.execIO(o, func(o *operation) error {
-               return windows.WSASendMsg(fd.Sysfd, &o.msg, 0, &o.qty, &o.o, nil)
+       n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
+               err = windows.WSASendMsg(fd.Sysfd, &o.msg, 0, nil, &o.o, nil)
+               return qty, err
        })
        return n, int(o.msg.Control.Len), err
 }

diff --git a/src/internal/poll/sendfile_windows.go b/src/internal/poll/sendfile_windows.go
index 67e7b2e76707851e94f4d293c15ba7900dae56ec..a052f4a1f82400c5d67e79b5cfe123283fd0229f 100644 (file)
--- a/src/internal/poll/sendfile_windows.go
+++ b/src/internal/poll/sendfile_windows.go
@@ -73,9 +73,12 @@ func SendFile(fd *FD, src uintptr, size int64) (written int64, err error, handle
                o.o.Offset = uint32(off)
                o.o.OffsetHigh = uint32(off >> 32)
 
-               n, err := fd.execIO(o, func(o *operation) error {
-                       o.qty = uint32(chunkSize)
-                       return syscall.TransmitFile(fd.Sysfd, hsrc, o.qty, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
+               n, err := fd.execIO(o, func(o *operation) (uint32, error) {
+                       err := syscall.TransmitFile(fd.Sysfd, hsrc, uint32(chunkSize), 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
+                       if err != nil {
+                               return 0, err
+                       }
+                       return uint32(chunkSize), nil
                })
                if err != nil {
                        return written, err, written > 0