Separate VT100 writer

Author: c-bata

console_interface.go

@@ -6,6 +6,7 @@ type WinSize struct {
 	Col uint16
 }
 
+// DisplayAttribute represents display  attributes like Blinking, Bold, Italic and so on.
 type DisplayAttribute int
 
 const (
@@ -163,5 +164,8 @@ type ConsoleWriter interface {
 	/* Font */
 
 	// SetColor sets text and background colors. and specify whether text is bold.
+	// Deprecated. This interface is not cool, please use SetDisplayAttributes.
 	SetColor(fg, bg Color, bold bool)
+	// SetDisplayAttributes set display attributes (Set colors, blink, bold, italic and so on).
+	SetDisplayAttributes(fg, bg Color, attrs ...DisplayAttribute)
 }

output_posix.go

@@ -3,40 +3,14 @@
 package prompt
 
 import (
-	"bytes"
-	"strconv"
 	"syscall"
 )
 
 // PosixWriter is a ConsoleWriter implementation for POSIX environment.
 // To control terminal emulator, this outputs VT100 escape sequences.
 type PosixWriter struct {
-	fd     int
-	buffer []byte
-}
-
-// WriteRaw to write raw byte array
-func (w *PosixWriter) WriteRaw(data []byte) {
-	w.buffer = append(w.buffer, data...)
-	return
-}
-
-// Write to write safety byte array by removing control sequences.
-func (w *PosixWriter) Write(data []byte) {
-	w.WriteRaw(bytes.Replace(data, []byte{0x1b}, []byte{'?'}, -1))
-	return
-}
-
-// WriteRawStr to write raw string
-func (w *PosixWriter) WriteRawStr(data string) {
-	w.WriteRaw([]byte(data))
-	return
-}
-
-// WriteStr to write safety string by removing control sequences.
-func (w *PosixWriter) WriteStr(data string) {
-	w.Write([]byte(data))
-	return
+	VT100Writer
+	fd int
 }
 
 // Flush to flush buffer
@@ -49,309 +23,11 @@ func (w *PosixWriter) Flush() error {
 	return nil
 }
 
-/* Erase */
-
-// EraseScreen erases the screen with the background colour and moves the cursor to home.
-func (w *PosixWriter) EraseScreen() {
-	w.WriteRaw([]byte{0x1b, '[', '2', 'J'})
-	return
-}
-
-// EraseUp erases the screen from the current line up to the top of the screen.
-func (w *PosixWriter) EraseUp() {
-	w.WriteRaw([]byte{0x1b, '[', '2', 'J'})
-	return
-}
-
-// EraseDown erases the screen from the current line down to the bottom of the screen.
-func (w *PosixWriter) EraseDown() {
-	w.WriteRaw([]byte{0x1b, '[', 'J'})
-	return
-}
-
-// EraseStartOfLine erases from the current cursor position to the start of the current line.
-func (w *PosixWriter) EraseStartOfLine() {
-	w.WriteRaw([]byte{0x1b, '[', '1', 'K'})
-	return
-}
-
-// EraseEndOfLine erases from the current cursor position to the end of the current line.
-func (w *PosixWriter) EraseEndOfLine() {
-	w.WriteRaw([]byte{0x1b, '[', 'K'})
-	return
-}
-
-// EraseLine erases the entire current line.
-func (w *PosixWriter) EraseLine() {
-	w.WriteRaw([]byte{0x1b, '[', '2', 'K'})
-	return
-}
-
-/* Cursor */
-
-// ShowCursor stops blinking cursor and show.
-func (w *PosixWriter) ShowCursor() {
-	w.WriteRaw([]byte{0x1b, '[', '?', '1', '2', 'l', 0x1b, '[', '?', '2', '5', 'h'})
-}
-
-// HideCursor hides cursor.
-func (w *PosixWriter) HideCursor() {
-	w.WriteRaw([]byte{0x1b, '[', '?', '2', '5', 'l'})
-	return
-}
-
-// CursorGoTo sets the cursor position where subsequent text will begin.
-func (w *PosixWriter) CursorGoTo(row, col int) {
-	if row == 0 && col == 0 {
-		// If no row/column parameters are provided (ie. <ESC>[H), the cursor will move to the home position.
-		w.WriteRaw([]byte{0x1b, '[', 'H'})
-		return
-	}
-	r := strconv.Itoa(row)
-	c := strconv.Itoa(col)
-	w.WriteRaw([]byte{0x1b, '['})
-	w.WriteRaw([]byte(r))
-	w.WriteRaw([]byte{';'})
-	w.WriteRaw([]byte(c))
-	w.WriteRaw([]byte{'H'})
-	return
-}
-
-// CursorUp moves the cursor up by 'n' rows; the default count is 1.
-func (w *PosixWriter) CursorUp(n int) {
-	if n == 0 {
-		return
-	} else if n < 0 {
-		w.CursorDown(-n)
-		return
-	}
-	s := strconv.Itoa(n)
-	w.WriteRaw([]byte{0x1b, '['})
-	w.WriteRaw([]byte(s))
-	w.WriteRaw([]byte{'A'})
-	return
-}
-
-// CursorDown moves the cursor down by 'n' rows; the default count is 1.
-func (w *PosixWriter) CursorDown(n int) {
-	if n == 0 {
-		return
-	} else if n < 0 {
-		w.CursorUp(-n)
-		return
-	}
-	s := strconv.Itoa(n)
-	w.WriteRaw([]byte{0x1b, '['})
-	w.WriteRaw([]byte(s))
-	w.WriteRaw([]byte{'B'})
-	return
-}
-
-// CursorForward moves the cursor forward by 'n' columns; the default count is 1.
-func (w *PosixWriter) CursorForward(n int) {
-	if n == 0 {
-		return
-	} else if n < 0 {
-		w.CursorBackward(-n)
-		return
-	}
-	s := strconv.Itoa(n)
-	w.WriteRaw([]byte{0x1b, '['})
-	w.WriteRaw([]byte(s))
-	w.WriteRaw([]byte{'C'})
-	return
-}
-
-// CursorBackward moves the cursor backward by 'n' columns; the default count is 1.
-func (w *PosixWriter) CursorBackward(n int) {
-	if n == 0 {
-		return
-	} else if n < 0 {
-		w.CursorForward(-n)
-		return
-	}
-	s := strconv.Itoa(n)
-	w.WriteRaw([]byte{0x1b, '['})
-	w.WriteRaw([]byte(s))
-	w.WriteRaw([]byte{'D'})
-	return
-}
-
-// AskForCPR asks for a cursor position report (CPR).
-func (w *PosixWriter) AskForCPR() {
-	// CPR: Cursor Position Request.
-	w.WriteRaw([]byte{0x1b, '[', '6', 'n'})
-	w.Flush()
-	return
-}
-
-// SaveCursor saves current cursor position.
-func (w *PosixWriter) SaveCursor() {
-	w.WriteRaw([]byte{0x1b, '[', 's'})
-	return
-}
-
-// UnSaveCursor restores cursor position after a Save Cursor.
-func (w *PosixWriter) UnSaveCursor() {
-	w.WriteRaw([]byte{0x1b, '[', 'u'})
-	return
-}
-
-/* Scrolling */
-
-// ScrollDown scrolls display down one line.
-func (w *PosixWriter) ScrollDown() {
-	w.WriteRaw([]byte{0x1b, 'D'})
-	return
-}
-
-// ScrollUp scroll display up one line.
-func (w *PosixWriter) ScrollUp() {
-	w.WriteRaw([]byte{0x1b, 'M'})
-	return
-}
-
-/* Title */
-
-// SetTitle sets a title of terminal window.
-func (w *PosixWriter) SetTitle(title string) {
-	titleBytes := []byte(title)
-	patterns := []struct {
-		from []byte
-		to   []byte
-	}{
-		{
-			from: []byte{0x13},
-			to:   []byte{},
-		},
-		{
-			from: []byte{0x07},
-			to:   []byte{},
-		},
-	}
-	for i := range patterns {
-		titleBytes = bytes.Replace(titleBytes, patterns[i].from, patterns[i].to, -1)
-	}
-
-	w.WriteRaw([]byte{0x1b, ']', '2', ';'})
-	w.WriteRaw(titleBytes)
-	w.WriteRaw([]byte{0x07})
-	return
-}
-
-// ClearTitle clears a title of terminal window.
-func (w *PosixWriter) ClearTitle() {
-	w.WriteRaw([]byte{0x1b, ']', '2', ';', 0x07})
-	return
-}
-
-/* Font */
-
-// SetColor sets text and background colors. and specify whether text is bold.
-// Deprecated. This interface is not cool, please use SetDisplayAttributes.
-func (w *PosixWriter) SetColor(fg, bg Color, bold bool) {
-	if bold {
-		w.SetDisplayAttributes(fg, bg, DisplayBold)
-	} else {
-		w.SetDisplayAttributes(fg, bg, DisplayDefaultFont)
-	}
-	return
-}
-
-// SetDisplayAttributes set display attributes (Set colors, blink, bold, italic and so on).
-func (w *PosixWriter) SetDisplayAttributes(fg, bg Color, attrs ...DisplayAttribute) {
-	w.WriteRaw([]byte{0x1b, '['}) // control sequence introducer
-	defer w.WriteRaw([]byte{'m'}) // final character
-
-	var separator byte = ';'
-	for i := range attrs {
-		p, ok := displayAttributeParameters[attrs[i]]
-		if !ok {
-			continue
-		}
-		w.WriteRaw(p)
-		w.WriteRaw([]byte{separator})
-	}
-
-	f, ok := foregroundANSIColors[fg]
-	if !ok {
-		f = foregroundANSIColors[DefaultColor]
-	}
-	w.WriteRaw(f)
-	w.WriteRaw([]byte{separator})
-	b, ok := backgroundANSIColors[bg]
-	if !ok {
-		b = backgroundANSIColors[DefaultColor]
-	}
-	w.WriteRaw(b)
-	return
-}
-
-var displayAttributeParameters = map[DisplayAttribute][]byte{
-	DisplayReset:        {'0'},
-	DisplayBold:         {'1'},
-	DisplayLowIntensity: {'2'},
-	DisplayItalic:       {'3'},
-	DisplayUnderline:    {'4'},
-	DisplayBlink:        {'5'},
-	DisplayRapidBlink:   {'6'},
-	DisplayReverse:      {'7'},
-	DisplayInvisible:    {'8'},
-	DisplayCrossedOut:   {'9'},
-	DisplayDefaultFont:  {'1', '0'},
-}
-
-var foregroundANSIColors = map[Color][]byte{
-	DefaultColor: {'3', '9'},
-
-	// Low intensity.
-	Black:     {'3', '0'},
-	DarkRed:   {'3', '1'},
-	DarkGreen: {'3', '2'},
-	Brown:     {'3', '3'},
-	DarkBlue:  {'3', '4'},
-	Purple:    {'3', '5'},
-	Cyan:      {'3', '6'},
-	LightGray: {'3', '7'},
-
-	// High intensity.
-	DarkGray:  {'9', '0'},
-	Red:       {'9', '1'},
-	Green:     {'9', '2'},
-	Yellow:    {'9', '3'},
-	Blue:      {'9', '4'},
-	Fuchsia:   {'9', '5'},
-	Turquoise: {'9', '6'},
-	White:     {'9', '7'},
-}
-
-var backgroundANSIColors = map[Color][]byte{
-	DefaultColor: {'4', '9'},
-
-	// Low intensity.
-	Black:     {'4', '0'},
-	DarkRed:   {'4', '1'},
-	DarkGreen: {'4', '2'},
-	Brown:     {'4', '3'},
-	DarkBlue:  {'4', '4'},
-	Purple:    {'4', '5'},
-	Cyan:      {'4', '6'},
-	LightGray: {'4', '7'},
-
-	// High intensity
-	DarkGray:  {'1', '0', '0'},
-	Red:       {'1', '0', '1'},
-	Green:     {'1', '0', '2'},
-	Yellow:    {'1', '0', '3'},
-	Blue:      {'1', '0', '4'},
-	Fuchsia:   {'1', '0', '5'},
-	Turquoise: {'1', '0', '6'},
-	White:     {'1', '0', '7'},
-}
-
 var _ ConsoleWriter = &PosixWriter{}
 
 // NewStandardOutputWriter returns ConsoleWriter object to write to stdout.
+// This generates VT100 escape sequences because almost terminal emulators
+// in POSIX OS built on top of a VT100 specification.
 func NewStandardOutputWriter() *PosixWriter {
 	return &PosixWriter{
 		fd: syscall.Stdout,