Add termstatus

internal/ui/termstatus/terminal_windows.go

@@ -0,0 +1,131 @@
+// +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
+}