restic/internal/ui/termstatus/terminal_windows.go

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2018-04-22 09:57:11 +00:00
// +build windows
package termstatus
import (
"io"
"syscall"
"unsafe"
)
// clearLines clears the current line and n lines above it.
func clearLines(wr io.Writer, fd uintptr) clearLinesFunc {
// easy case, the terminal is cmd or psh, without redirection
if isWindowsTerminal(fd) {
return windowsClearLines
}
// check if the output file type is a pipe (0x0003)
if getFileType(fd) != fileTypePipe {
// return empty func, update state is not possible on this terminal
return func(io.Writer, uintptr, int) {}
}
// assume we're running in mintty/cygwin
return posixClearLines
}
var kernel32 = syscall.NewLazyDLL("kernel32.dll")
var (
procGetConsoleScreenBufferInfo = kernel32.NewProc("GetConsoleScreenBufferInfo")
procSetConsoleCursorPosition = kernel32.NewProc("SetConsoleCursorPosition")
procFillConsoleOutputCharacter = kernel32.NewProc("FillConsoleOutputCharacterW")
procFillConsoleOutputAttribute = kernel32.NewProc("FillConsoleOutputAttribute")
procGetConsoleMode = kernel32.NewProc("GetConsoleMode")
procGetFileType = kernel32.NewProc("GetFileType")
)
type (
short int16
word uint16
dword uint32
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
}
)
// windowsClearLines clears the current line and n lines above it.
func windowsClearLines(wr io.Writer, fd uintptr, n int) {
var info consoleScreenBufferInfo
procGetConsoleScreenBufferInfo.Call(fd, uintptr(unsafe.Pointer(&info)))
for i := 0; i <= n; i++ {
// clear the line
cursor := coord{
x: info.window.left,
y: info.cursorPosition.y - short(i),
}
var count, w dword
count = dword(info.size.x)
procFillConsoleOutputAttribute.Call(fd, uintptr(info.attributes), uintptr(count), *(*uintptr)(unsafe.Pointer(&cursor)), uintptr(unsafe.Pointer(&w)))
procFillConsoleOutputCharacter.Call(fd, uintptr(' '), uintptr(count), *(*uintptr)(unsafe.Pointer(&cursor)), uintptr(unsafe.Pointer(&w)))
}
// move cursor up by n lines and to the first column
info.cursorPosition.y -= short(n)
info.cursorPosition.x = 0
procSetConsoleCursorPosition.Call(fd, uintptr(*(*int32)(unsafe.Pointer(&info.cursorPosition))))
}
// getTermSize returns the dimensions of the given terminal.
// the code is taken from "golang.org/x/crypto/ssh/terminal"
func getTermSize(fd uintptr) (width, height int, err error) {
var info consoleScreenBufferInfo
_, _, e := syscall.Syscall(procGetConsoleScreenBufferInfo.Addr(), 2, fd, uintptr(unsafe.Pointer(&info)), 0)
if e != 0 {
return 0, 0, error(e)
}
return int(info.size.x), int(info.size.y), nil
}
// isWindowsTerminal return true if the file descriptor is a windows terminal (cmd, psh).
func isWindowsTerminal(fd uintptr) bool {
var st uint32
r, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, fd, uintptr(unsafe.Pointer(&st)), 0)
return r != 0 && e == 0
}
const fileTypePipe = 0x0003
// getFileType returns the file type for the given fd.
// https://msdn.microsoft.com/de-de/library/windows/desktop/aa364960(v=vs.85).aspx
func getFileType(fd uintptr) int {
r, _, e := syscall.Syscall(procGetFileType.Addr(), 1, fd, 0, 0)
if e != 0 {
return 0
}
return int(r)
}
// canUpdateStatus returns true if status lines can be printed, the process
// output is not redirected to a file or pipe.
func canUpdateStatus(fd uintptr) bool {
// easy case, the terminal is cmd or psh, without redirection
if isWindowsTerminal(fd) {
return true
}
// check if the output file type is a pipe (0x0003)
if getFileType(fd) != fileTypePipe {
return false
}
// assume we're running in mintty/cygwin
return true
}