// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build windows
// Package terminal provides support functions for dealing with terminals, as
// commonly found on UNIX systems.
//
// Putting a terminal into raw mode is the most common requirement:
//
// oldState, err := terminal.MakeRaw(0)
// if err != nil {
// panic(err)
// }
// defer terminal.Restore(0, oldState)
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
}
)
type State struct {
mode uint32
}
// 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
}
// MakeRaw put the terminal connected to the given file descriptor into raw
// mode and returns the previous state of the terminal so that it can be
// 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)
}
raw := st &^ (enableEchoInput | enableProcessedInput | enableLineInput | enableProcessedOutput)
_, _, e = syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(raw), 0)
if e != 0 {
return nil, error(e)
}
return &State{st}, nil
}
// GetState returns the current state of a terminal which may be useful to
// 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)
}
return &State{st}, nil
}
// 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
}
// 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)
}
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)
}
// ReadPassword reads a line of input from a terminal without local echo. This
// is commonly used for inputting passwords and other sensitive data. The slice
// 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)
}
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)
}
defer func() {
syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(old), 0)
}()
return readPasswordLine(passwordReader(fd))
}