ssh/terminal: use console functions, types and consts from x/sys/windows

Use GetConsoleMode, SetConsoleMode and GetConsoleScreenBufferInfo and
the corresponding types and constants from golang.org/x/sys/windows
instead of locally defining them.

Change-Id: I69292a47114d071be261ffda6ca620a0b9820d00
Reviewed-on: https://go-review.googlesource.com/52990
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

ssh/terminal/util_windows.go

@@ -17,53 +17,7 @@
 package terminal
 
 import (
-	"syscall"
-	"unsafe"
-)
-
-const (
-	enableLineInput       = 2
-	enableEchoInput       = 4
-	enableProcessedInput  = 1
-	enableWindowInput     = 8
-	enableMouseInput      = 16
-	enableInsertMode      = 32
-	enableQuickEditMode   = 64
-	enableExtendedFlags   = 128
-	enableAutoPosition    = 256
-	enableProcessedOutput = 1
-	enableWrapAtEolOutput = 2
-)
-
-var kernel32 = syscall.NewLazyDLL("kernel32.dll")
-
-var (
-	procGetConsoleMode             = kernel32.NewProc("GetConsoleMode")
-	procSetConsoleMode             = kernel32.NewProc("SetConsoleMode")
-	procGetConsoleScreenBufferInfo = kernel32.NewProc("GetConsoleScreenBufferInfo")
-)
-
-type (
-	short int16
-	word  uint16
-
-	coord struct {
-		x short
-		y short
-	}
-	smallRect struct {
-		left   short
-		top    short
-		right  short
-		bottom short
-	}
-	consoleScreenBufferInfo struct {
-		size              coord
-		cursorPosition    coord
-		attributes        word
-		window            smallRect
-		maximumWindowSize coord
-	}
+	"golang.org/x/sys/windows"
 )
 
 type State struct {
@@ -73,8 +27,8 @@ type State struct {
 // IsTerminal returns true if the given file descriptor is a terminal.
 func IsTerminal(fd int) bool {
 	var st uint32
-	r, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
-	return r != 0 && e == 0
+	err := windows.GetConsoleMode(windows.Handle(fd), &st)
+	return err == nil
 }
 
 // MakeRaw put the terminal connected to the given file descriptor into raw
@@ -82,14 +36,12 @@ func IsTerminal(fd int) bool {
 // restored.
 func MakeRaw(fd int) (*State, error) {
 	var st uint32
-	_, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
-	if e != 0 {
-		return nil, error(e)
+	if err := windows.GetConsoleMode(windows.Handle(fd), &st); err != nil {
+		return nil, err
 	}
-	raw := st &^ (enableEchoInput | enableProcessedInput | enableLineInput | enableProcessedOutput)
-	_, _, e = syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(raw), 0)
-	if e != 0 {
-		return nil, error(e)
+	raw := st &^ (windows.ENABLE_ECHO_INPUT | windows.ENABLE_PROCESSED_INPUT | windows.ENABLE_LINE_INPUT | windows.ENABLE_PROCESSED_OUTPUT)
+	if err := windows.SetConsoleMode(windows.Handle(fd), raw); err != nil {
+		return nil, err
 	}
 	return &State{st}, nil
 }
@@ -98,9 +50,8 @@ func MakeRaw(fd int) (*State, error) {
 // restore the terminal after a signal.
 func GetState(fd int) (*State, error) {
 	var st uint32
-	_, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
-	if e != 0 {
-		return nil, error(e)
+	if err := windows.GetConsoleMode(windows.Handle(fd), &st); err != nil {
+		return nil, err
 	}
 	return &State{st}, nil
 }
@@ -108,25 +59,23 @@ func GetState(fd int) (*State, error) {
 // Restore restores the terminal connected to the given file descriptor to a
 // previous state.
 func Restore(fd int, state *State) error {
-	_, _, err := syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(state.mode), 0)
-	return err
+	return windows.SetConsoleMode(windows.Handle(fd), state.mode)
 }
 
 // GetSize returns the dimensions of the given terminal.
 func GetSize(fd int) (width, height int, err error) {
-	var info consoleScreenBufferInfo
-	_, _, e := syscall.Syscall(procGetConsoleScreenBufferInfo.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&info)), 0)
-	if e != 0 {
-		return 0, 0, error(e)
+	var info windows.ConsoleScreenBufferInfo
+	if err := windows.GetConsoleScreenBufferInfo(windows.Handle(fd), &info); err != nil {
+		return 0, 0, err
 	}
-	return int(info.size.x), int(info.size.y), nil
+	return int(info.Size.X), int(info.Size.Y), nil
 }
 
 // passwordReader is an io.Reader that reads from a specific Windows HANDLE.
 type passwordReader int
 
 func (r passwordReader) Read(buf []byte) (int, error) {
-	return syscall.Read(syscall.Handle(r), buf)
+	return windows.Read(windows.Handle(r), buf)
 }
 
 // ReadPassword reads a line of input from a terminal without local echo.  This
@@ -134,21 +83,19 @@ func (r passwordReader) Read(buf []byte) (int, error) {
 // returned does not include the \n.
 func ReadPassword(fd int) ([]byte, error) {
 	var st uint32
-	_, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
-	if e != 0 {
-		return nil, error(e)
+	if err := windows.GetConsoleMode(windows.Handle(fd), &st); err != nil {
+		return nil, err
 	}
 	old := st
 
-	st &^= (enableEchoInput)
-	st |= (enableProcessedInput | enableLineInput | enableProcessedOutput)
-	_, _, e = syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(st), 0)
-	if e != 0 {
-		return nil, error(e)
+	st &^= (windows.ENABLE_ECHO_INPUT)
+	st |= (windows.ENABLE_PROCESSED_INPUT | windows.ENABLE_LINE_INPUT | windows.ENABLE_PROCESSED_OUTPUT)
+	if err := windows.SetConsoleMode(windows.Handle(fd), st); err != nil {
+		return nil, err
 	}
 
 	defer func() {
-		syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(old), 0)
+		windows.SetConsoleMode(windows.Handle(fd), old)
 	}()
 
 	return readPasswordLine(passwordReader(fd))