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restic/internal/ui/termstatus/terminal_windows.go
Michael Eischer 80564a9bc9 Properly detect mintty output redirection
mintty on windows always uses pipes to connect stdout between processes
and for the terminal output. The previous implementation always assumed
that stdout connected to a pipe means that stdout is displayed on a
mintty terminal. However, this detection breaks when using pipes to
connect processes and for powershell which uses pipes when redirecting
to a file.

Now the pipe filename is queried and matched against the pattern used by
msys / cygwin when connected to the terminal. In all other cases assume
that a pipe is just a regular pipe.
2021-04-11 20:02:09 +02:00

127 lines
3.7 KiB
Go

// +build windows
package termstatus
import (
"io"
"strings"
"syscall"
"unsafe"
"golang.org/x/crypto/ssh/terminal"
"golang.org/x/sys/windows"
)
// clearCurrentLine removes all characters from the current line and resets the
// cursor position to the first column.
func clearCurrentLine(wr io.Writer, fd uintptr) func(io.Writer, uintptr) {
// easy case, the terminal is cmd or psh, without redirection
if isWindowsTerminal(fd) {
return windowsClearCurrentLine
}
// assume we're running in mintty/cygwin
return posixClearCurrentLine
}
// moveCursorUp moves the cursor to the line n lines above the current one.
func moveCursorUp(wr io.Writer, fd uintptr) func(io.Writer, uintptr, int) {
// easy case, the terminal is cmd or psh, without redirection
if isWindowsTerminal(fd) {
return windowsMoveCursorUp
}
// assume we're running in mintty/cygwin
return posixMoveCursorUp
}
var kernel32 = syscall.NewLazyDLL("kernel32.dll")
var (
procFillConsoleOutputCharacter = kernel32.NewProc("FillConsoleOutputCharacterW")
procFillConsoleOutputAttribute = kernel32.NewProc("FillConsoleOutputAttribute")
)
// windowsClearCurrentLine removes all characters from the current line and
// resets the cursor position to the first column.
func windowsClearCurrentLine(wr io.Writer, fd uintptr) {
var info windows.ConsoleScreenBufferInfo
windows.GetConsoleScreenBufferInfo(windows.Handle(fd), &info)
// clear the line
cursor := windows.Coord{
X: info.Window.Left,
Y: info.CursorPosition.Y,
}
var count, w uint32
count = uint32(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)))
}
// windowsMoveCursorUp moves the cursor to the line n lines above the current one.
func windowsMoveCursorUp(wr io.Writer, fd uintptr, n int) {
var info windows.ConsoleScreenBufferInfo
windows.GetConsoleScreenBufferInfo(windows.Handle(fd), &info)
// move cursor up by n lines and to the first column
windows.SetConsoleCursorPosition(windows.Handle(fd), windows.Coord{
X: 0,
Y: info.CursorPosition.Y - int16(n),
})
}
// isWindowsTerminal return true if the file descriptor is a windows terminal (cmd, psh).
func isWindowsTerminal(fd uintptr) bool {
return terminal.IsTerminal(int(fd))
}
func isPipe(fd uintptr) bool {
typ, err := windows.GetFileType(windows.Handle(fd))
return err == nil && typ == windows.FILE_TYPE_PIPE
}
func getFileNameByHandle(fd uintptr) (string, error) {
type FILE_NAME_INFO struct {
FileNameLength int32
FileName [windows.MAX_LONG_PATH]uint16
}
var fi FILE_NAME_INFO
err := windows.GetFileInformationByHandleEx(windows.Handle(fd), windows.FileNameInfo, (*byte)(unsafe.Pointer(&fi)), uint32(unsafe.Sizeof(fi)))
if err != nil {
return "", err
}
filename := syscall.UTF16ToString(fi.FileName[:])
return filename, nil
}
// 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
}
// pipes require special handling
if !isPipe(fd) {
return false
}
fn, err := getFileNameByHandle(fd)
if err != nil {
return false
}
// inspired by https://github.com/RyanGlScott/mintty/blob/master/src/System/Console/MinTTY/Win32.hsc
// terminal: \msys-dd50a72ab4668b33-pty0-to-master
// pipe to cat: \msys-dd50a72ab4668b33-13244-pipe-0x16
if (strings.HasPrefix(fn, "\\cygwin-") || strings.HasPrefix(fn, "\\msys-")) &&
strings.Contains(fn, "-pty") && strings.HasSuffix(fn, "-master") {
return true
}
return false
}