termstatus: move cursor handling to terminal package

internal/terminal/terminal_posix.go

@@ -0,0 +1,36 @@
+package terminal
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+)
+
+const (
+	PosixControlMoveCursorHome = "\r"
+	PosixControlMoveCursorUp   = "\x1b[1A"
+	PosixControlClearLine      = "\x1b[2K"
+)
+
+// posixClearCurrentLine removes all characters from the current line and resets the
+// cursor position to the first column.
+func PosixClearCurrentLine(wr io.Writer, _ uintptr) {
+	// clear current line
+	_, err := wr.Write([]byte(PosixControlMoveCursorHome + PosixControlClearLine))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
+		return
+	}
+}
+
+// posixMoveCursorUp moves the cursor to the line n lines above the current one.
+func PosixMoveCursorUp(wr io.Writer, _ uintptr, n int) {
+	data := []byte(PosixControlMoveCursorHome)
+	data = append(data, bytes.Repeat([]byte(PosixControlMoveCursorUp), n)...)
+	_, err := wr.Write(data)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
+		return
+	}
+}

internal/terminal/terminal_unix.go

@@ -0,0 +1,36 @@
+//go:build !windows
+// +build !windows
+
+package terminal
+
+import (
+	"io"
+	"os"
+
+	"golang.org/x/term"
+)
+
+// clearCurrentLine removes all characters from the current line and resets the
+// cursor position to the first column.
+func ClearCurrentLine(_ uintptr) func(io.Writer, uintptr) {
+	return PosixClearCurrentLine
+}
+
+// moveCursorUp moves the cursor to the line n lines above the current one.
+func MoveCursorUp(_ uintptr) func(io.Writer, uintptr, int) {
+	return PosixMoveCursorUp
+}
+
+// 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 {
+	if !term.IsTerminal(int(fd)) {
+		return false
+	}
+	term := os.Getenv("TERM")
+	if term == "" {
+		return false
+	}
+	// TODO actually read termcap db and detect if terminal supports what we need
+	return term != "dumb"
+}

internal/terminal/terminal_windows.go

@@ -0,0 +1,128 @@
+//go:build windows
+// +build windows
+
+package terminal
+
+import (
+	"io"
+	"strings"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+	"golang.org/x/term"
+)
+
+// clearCurrentLine removes all characters from the current line and resets the
+// cursor position to the first column.
+func ClearCurrentLine(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(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(_ 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(_ 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 term.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
+}

internal/terminal/terminal_windows_test.go

@@ -0,0 +1,30 @@
+package terminal
+
+import (
+	"syscall"
+	"testing"
+
+	"golang.org/x/sys/windows"
+
+	rtest "github.com/restic/restic/internal/test"
+)
+
+func TestIsMinTTY(t *testing.T) {
+	for _, test := range []struct {
+		path   string
+		result bool
+	}{
+		{`\\.\pipe\msys-dd50a72ab4668b33-pty0-to-master`, true},
+		{`\\.\pipe\msys-dd50a72ab4668b33-13244-pipe-0x16`, false},
+	} {
+		filename, err := syscall.UTF16FromString(test.path)
+		rtest.OK(t, err)
+		handle, err := windows.CreateNamedPipe(&filename[0], windows.PIPE_ACCESS_DUPLEX,
+			windows.PIPE_TYPE_BYTE, 1, 1024, 1024, 0, nil)
+		rtest.OK(t, err)
+		defer windows.CloseHandle(handle)
+
+		rtest.Assert(t, CanUpdateStatus(uintptr(handle)) == test.result,
+			"expected CanUpdateStatus(%v) == %v", test.path, test.result)
+	}
+}