add the terminal module which is copied from code.google.com/golang/ssh/terminal

terminal/terminal.go

@@ -0,0 +1,731 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package terminal
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"sync"
+)
+
+func max(i, j int) int {
+	if i > j {
+		return i
+	}
+	return j
+}
+
+func min(i, j int) int {
+	if i < j {
+		return i
+	}
+	return j
+}
+
+// historyIdxValue returns an index into a valid range of history
+func historyIdxValue(idx int, history [][]byte) int {
+	out := idx
+	out = min(len(history), out)
+	out = max(0, out)
+	return out
+}
+
+// EscapeCodes contains escape sequences that can be written to the terminal in
+// order to achieve different styles of text.
+type EscapeCodes struct {
+	// Foreground colors
+	Black, Red, Green, Yellow, Blue, Magenta, Cyan, White []byte
+
+	// Reset all attributes
+	Reset []byte
+}
+
+var vt100EscapeCodes = EscapeCodes{
+	Black:   []byte{KeyEscape, '[', '3', '0', 'm'},
+	Red:     []byte{KeyEscape, '[', '3', '1', 'm'},
+	Green:   []byte{KeyEscape, '[', '3', '2', 'm'},
+	Yellow:  []byte{KeyEscape, '[', '3', '3', 'm'},
+	Blue:    []byte{KeyEscape, '[', '3', '4', 'm'},
+	Magenta: []byte{KeyEscape, '[', '3', '5', 'm'},
+	Cyan:    []byte{KeyEscape, '[', '3', '6', 'm'},
+	White:   []byte{KeyEscape, '[', '3', '7', 'm'},
+
+	Reset: []byte{KeyEscape, '[', '0', 'm'},
+}
+
+// Terminal contains the state for running a VT100 terminal that is capable of
+// reading lines of input.
+type Terminal struct {
+	// AutoCompleteCallback, if non-null, is called for each keypress
+	// with the full input line and the current position of the cursor.
+	// If it returns a nil newLine, the key press is processed normally.
+	// Otherwise it returns a replacement line and the new cursor position.
+	AutoCompleteCallback func(line []byte, pos, key int) (newLine []byte, newPos int)
+
+	// Escape contains a pointer to the escape codes for this terminal.
+	// It's always a valid pointer, although the escape codes themselves
+	// may be empty if the terminal doesn't support them.
+	Escape *EscapeCodes
+
+	// lock protects the terminal and the state in this object from
+	// concurrent processing of a key press and a Write() call.
+	lock sync.Mutex
+
+	c      io.ReadWriter
+	prompt string
+
+	// line is the current line being entered.
+	line []byte
+	// history is a buffer of previously entered lines
+	history [][]byte
+	// index into the history buffer (for use in the handleKey(KeyUp) function)
+	historyIdx int
+	// pos is the logical position of the cursor in line
+	pos int
+	// echo is true if local echo is enabled
+	echo bool
+
+	// cursorX contains the current X value of the cursor where the left
+	// edge is 0. cursorY contains the row number where the first row of
+	// the current line is 0.
+	cursorX, cursorY int
+	// maxLine is the greatest value of cursorY so far.
+	maxLine int
+
+	termWidth, termHeight int
+
+	// outBuf contains the terminal data to be sent.
+	outBuf []byte
+	// remainder contains the remainder of any partial key sequences after
+	// a read. It aliases into inBuf.
+	remainder []byte
+	inBuf     [256]byte
+}
+
+// NewTerminal runs a VT100 terminal on the given ReadWriter. If the ReadWriter is
+// a local terminal, that terminal must first have been put into raw mode.
+// prompt is a string that is written at the start of each input line (i.e.
+// "> ").
+func NewTerminal(c io.ReadWriter, prompt string) *Terminal {
+	return &Terminal{
+		Escape:     &vt100EscapeCodes,
+		c:          c,
+		prompt:     prompt,
+		history:    make([][]byte, 0, 100),
+		historyIdx: -1,
+		termWidth:  80,
+		termHeight: 24,
+		echo:       true,
+	}
+}
+
+const (
+	KeyCtrlC     = 3
+	KeyCtrlD     = 4
+	KeyEnter     = '\r'
+	KeyEscape    = 27
+	KeyBackspace = 127
+	KeyUnknown   = 256 + iota
+	KeyLeft
+	KeyUp
+	KeyRight
+	KeyDown
+	KeyAltLeft
+	KeyAltRight
+)
+
+// bytesToKey tries to parse a key sequence from b. If successful, it returns
+// the key and the remainder of the input. Otherwise it returns -1.
+func bytesToKey(b []byte) (int, []byte) {
+	if len(b) == 0 {
+		return -1, nil
+	}
+
+	if b[0] != KeyEscape {
+		return int(b[0]), b[1:]
+	}
+
+	if len(b) >= 3 && b[0] == KeyEscape && b[1] == '[' {
+		switch b[2] {
+		case 'A':
+			return KeyUp, b[3:]
+		case 'B':
+			return KeyDown, b[3:]
+		case 'C':
+			return KeyRight, b[3:]
+		case 'D':
+			return KeyLeft, b[3:]
+		}
+	}
+
+	if len(b) >= 6 &&
+		b[0] == KeyEscape &&
+		b[1] == '[' &&
+		b[2] == '1' &&
+		b[3] == ';' &&
+		b[4] == '3' {
+		switch b[5] {
+		case 'C':
+			return KeyAltRight, b[6:]
+		case 'D':
+			return KeyAltLeft, b[6:]
+		}
+	}
+
+	// If we get here then we have a key that we don't recognise, or a
+	// partial sequence. It's not clear how one should find the end of a
+	// sequence without knowing them all, but it seems that [a-zA-Z] only
+	// appears at the end of a sequence.
+	for i, c := range b[0:] {
+		if c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' {
+			return KeyUnknown, b[i+1:]
+		}
+	}
+
+	return -1, b
+}
+
+// queue appends data to the end of t.outBuf
+func (t *Terminal) queue(data []byte) {
+	t.outBuf = append(t.outBuf, data...)
+}
+
+var eraseUnderCursor = []byte{' ', KeyEscape, '[', 'D'}
+var space = []byte{' '}
+
+func isPrintable(key int) bool {
+	return key >= 32 && key < 127
+}
+
+// moveCursorToPos appends data to t.outBuf which will move the cursor to the
+// given, logical position in the text.
+func (t *Terminal) moveCursorToPos(pos int) {
+	if !t.echo {
+		return
+	}
+
+	x := len(t.prompt) + pos
+	y := x / t.termWidth
+	x = x % t.termWidth
+
+	up := 0
+	if y < t.cursorY {
+		up = t.cursorY - y
+	}
+
+	down := 0
+	if y > t.cursorY {
+		down = y - t.cursorY
+	}
+
+	left := 0
+	if x < t.cursorX {
+		left = t.cursorX - x
+	}
+
+	right := 0
+	if x > t.cursorX {
+		right = x - t.cursorX
+	}
+
+	t.cursorX = x
+	t.cursorY = y
+	t.move(up, down, left, right)
+}
+
+func (t *Terminal) move(up, down, left, right int) {
+	movement := make([]byte, 3*(up+down+left+right))
+	m := movement
+	for i := 0; i < up; i++ {
+		m[0] = KeyEscape
+		m[1] = '['
+		m[2] = 'A'
+		m = m[3:]
+	}
+	for i := 0; i < down; i++ {
+		m[0] = KeyEscape
+		m[1] = '['
+		m[2] = 'B'
+		m = m[3:]
+	}
+	for i := 0; i < left; i++ {
+		m[0] = KeyEscape
+		m[1] = '['
+		m[2] = 'D'
+		m = m[3:]
+	}
+	for i := 0; i < right; i++ {
+		m[0] = KeyEscape
+		m[1] = '['
+		m[2] = 'C'
+		m = m[3:]
+	}
+
+	t.queue(movement)
+}
+
+func (t *Terminal) clearLineToRight() {
+	op := []byte{KeyEscape, '[', 'K'}
+	t.queue(op)
+}
+
+const maxLineLength = 4096
+
+// handleKey processes the given key and, optionally, returns a line of text
+// that the user has entered.
+func (t *Terminal) handleKey(key int) (line string, ok bool) {
+	switch key {
+	case KeyBackspace:
+		if t.pos == 0 {
+			return
+		}
+		t.pos--
+		t.moveCursorToPos(t.pos)
+
+		copy(t.line[t.pos:], t.line[1+t.pos:])
+		t.line = t.line[:len(t.line)-1]
+		if t.echo {
+			t.writeLine(t.line[t.pos:])
+		}
+		t.queue(eraseUnderCursor)
+		t.moveCursorToPos(t.pos)
+	case KeyAltLeft:
+		// move left by a word.
+		if t.pos == 0 {
+			return
+		}
+		t.pos--
+		for t.pos > 0 {
+			if t.line[t.pos] != ' ' {
+				break
+			}
+			t.pos--
+		}
+		for t.pos > 0 {
+			if t.line[t.pos] == ' ' {
+				t.pos++
+				break
+			}
+			t.pos--
+		}
+		t.moveCursorToPos(t.pos)
+	case KeyAltRight:
+		// move right by a word.
+		for t.pos < len(t.line) {
+			if t.line[t.pos] == ' ' {
+				break
+			}
+			t.pos++
+		}
+		for t.pos < len(t.line) {
+			if t.line[t.pos] != ' ' {
+				break
+			}
+			t.pos++
+		}
+		t.moveCursorToPos(t.pos)
+	case KeyLeft:
+		if t.pos == 0 {
+			return
+		}
+		t.pos--
+		t.moveCursorToPos(t.pos)
+	case KeyRight:
+		if t.pos == len(t.line) {
+			return
+		}
+		t.pos++
+		t.moveCursorToPos(t.pos)
+	case KeyUp:
+		if len(t.history) == 0 {
+			return
+		}
+		t.historyIdx--
+		t.historyIdx = historyIdxValue(t.historyIdx, t.history)
+
+		h := t.history[t.historyIdx]
+		newLine := make([]byte, len(h))
+		copy(newLine, h)
+		newPos := len(newLine)
+		if t.echo {
+			t.moveCursorToPos(0)
+			t.writeLine(newLine)
+			for i := len(newLine); i < len(t.line); i++ {
+				t.writeLine(space)
+			}
+			t.moveCursorToPos(newPos)
+		}
+		t.line = newLine
+		t.pos = newPos
+		return
+
+	case KeyDown:
+		if len(t.history) == 0 {
+			return
+		}
+		newPos := 0
+		newLine := []byte{}
+		t.historyIdx++
+		if t.historyIdx >= len(t.history) {
+			t.historyIdx = len(t.history)
+		} else {
+			t.historyIdx = historyIdxValue(t.historyIdx, t.history)
+			h := t.history[t.historyIdx]
+			newLine = make([]byte, len(h))
+			copy(newLine, h)
+			newPos = len(newLine)
+			//			fmt.Println("in")
+		}
+		if t.echo {
+			t.moveCursorToPos(0)
+			t.writeLine(newLine)
+			for i := len(newLine); i < len(t.line); i++ {
+				t.writeLine(space)
+			}
+			t.moveCursorToPos(newPos)
+		}
+		t.line = newLine
+		t.pos = newPos
+		return
+
+	case KeyEnter:
+		t.moveCursorToPos(len(t.line))
+		t.queue([]byte("\r\n"))
+		line = string(t.line)
+		ok = true
+		t.line = t.line[:0]
+		t.pos = 0
+		t.cursorX = 0
+		t.cursorY = 0
+		t.maxLine = 0
+		t.historyIdx = len(t.history) + 1
+	case KeyCtrlD:
+		// add 'exit' to the end of the line
+		ok = true
+		if len(t.line) == 0 {
+			if len(t.line) == maxLineLength {
+				return
+			}
+			if len(t.line) == cap(t.line) {
+				newLine := make([]byte, len(t.line), 2*(2+len(t.line)))
+				copy(newLine, t.line)
+				t.line = newLine
+			}
+			t.line = t.line[:len(t.line)+4]
+			copy(t.line[t.pos+4:], t.line[t.pos:])
+			t.line[t.pos] = byte('e')
+			if t.echo {
+				t.writeLine(t.line[t.pos:])
+			}
+			t.pos++
+			t.moveCursorToPos(t.pos)
+			t.line[t.pos] = byte('x')
+			if t.echo {
+				t.writeLine(t.line[t.pos:])
+			}
+			t.pos++
+			t.moveCursorToPos(t.pos)
+			t.line[t.pos] = byte('i')
+			if t.echo {
+				t.writeLine(t.line[t.pos:])
+			}
+			t.pos++
+			t.moveCursorToPos(t.pos)
+			t.line[t.pos] = byte('t')
+			if t.echo {
+				t.writeLine(t.line[t.pos:])
+			}
+			t.pos++
+			t.moveCursorToPos(t.pos)
+		}
+	case KeyCtrlC:
+		// add '^C' to the end of the line
+		if len(t.line) == maxLineLength {
+			return
+		}
+		newLine := make([]byte, len(t.line), 2*(2+len(t.line)))
+		copy(newLine, t.line)
+		t.line = newLine
+		t.line = t.line[:len(t.line)+3]
+		copy(t.line[t.pos+3:], t.line[t.pos:])
+		t.line[t.pos] = byte('^')
+		t.pos++
+		t.line[t.pos] = byte('C')
+		if t.echo {
+			t.writeLine(t.line[t.pos-1:])
+		}
+		t.pos ++
+		t.moveCursorToPos(t.pos)
+		t.queue([]byte("\r\n"))
+		t.line = make([]byte, 0, 0)
+		t.pos = 0
+		t.cursorX = 0
+		t.cursorY = 0
+
+	default:
+		if t.AutoCompleteCallback != nil {
+			t.lock.Unlock()
+			newLine, newPos := t.AutoCompleteCallback(t.line, t.pos, key)
+			t.lock.Lock()
+
+			if newLine != nil {
+				if t.echo {
+					t.moveCursorToPos(0)
+					t.writeLine(newLine)
+					for i := len(newLine); i < len(t.line); i++ {
+						t.writeLine(space)
+					}
+					t.moveCursorToPos(newPos)
+				}
+				t.line = newLine
+				t.pos = newPos
+				return
+			}
+		}
+		if !isPrintable(key) {
+			return
+		}
+		if len(t.line) == maxLineLength {
+			return
+		}
+		if len(t.line) == cap(t.line) {
+			newLine := make([]byte, len(t.line), 2*(1+len(t.line)))
+			copy(newLine, t.line)
+			t.line = newLine
+		}
+		t.line = t.line[:len(t.line)+1]
+		copy(t.line[t.pos+1:], t.line[t.pos:])
+		t.line[t.pos] = byte(key)
+		if t.echo {
+			t.writeLine(t.line[t.pos:])
+		}
+		t.pos++
+		t.moveCursorToPos(t.pos)
+	}
+	return
+}
+
+func (t *Terminal) writeLine(line []byte) {
+	for len(line) != 0 {
+		remainingOnLine := t.termWidth - t.cursorX
+		todo := len(line)
+		if todo > remainingOnLine {
+			todo = remainingOnLine
+		}
+		t.queue(line[:todo])
+		t.cursorX += todo
+		line = line[todo:]
+
+		if t.cursorX == t.termWidth {
+			t.cursorX = 0
+			t.cursorY++
+			if t.cursorY > t.maxLine {
+				t.maxLine = t.cursorY
+			}
+		}
+	}
+}
+
+func (t *Terminal) Write(buf []byte) (n int, err error) {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	if t.cursorX == 0 && t.cursorY == 0 {
+		// This is the easy case: there's nothing on the screen that we
+		// have to move out of the way.
+		return t.c.Write(buf)
+	}
+
+	// We have a prompt and possibly user input on the screen. We
+	// have to clear it first.
+	t.move(0 /* up */, 0 /* down */, t.cursorX /* left */, 0 /* right */)
+	t.cursorX = 0
+	t.clearLineToRight()
+
+	for t.cursorY > 0 {
+		t.move(1 /* up */, 0, 0, 0)
+		t.cursorY--
+		t.clearLineToRight()
+	}
+
+	if _, err = t.c.Write(t.outBuf); err != nil {
+		return
+	}
+	t.outBuf = t.outBuf[:0]
+
+	if n, err = t.c.Write(buf); err != nil {
+		return
+	}
+
+	t.queue([]byte(t.prompt))
+	chars := len(t.prompt)
+	if t.echo {
+		t.queue(t.line)
+		chars += len(t.line)
+	}
+	t.cursorX = chars % t.termWidth
+	t.cursorY = chars / t.termWidth
+	t.moveCursorToPos(t.pos)
+
+	if _, err = t.c.Write(t.outBuf); err != nil {
+		return
+	}
+	t.outBuf = t.outBuf[:0]
+	return
+}
+
+// ReadPassword temporarily changes the prompt and reads a password, without
+// echo, from the terminal.
+func (t *Terminal) ReadPassword(prompt string) (line string, err error) {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	oldPrompt := t.prompt
+	t.prompt = prompt
+	t.echo = false
+
+	line, err = t.readLine()
+
+	t.prompt = oldPrompt
+	t.echo = true
+
+	return
+}
+
+// ReadLine returns a line of input from the terminal.
+func (t *Terminal) ReadLine() (line string, err error) {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	return t.readLine()
+}
+
+func (t *Terminal) readLine() (line string, err error) {
+	// t.lock must be held at this point
+
+	if t.cursorX == 0 && t.cursorY == 0 {
+		t.writeLine([]byte(t.prompt))
+		t.c.Write(t.outBuf)
+		t.outBuf = t.outBuf[:0]
+	}
+
+	for {
+		rest := t.remainder
+		lineOk := false
+		for !lineOk {
+			var key int
+			key, rest = bytesToKey(rest)
+			if key < 0 {
+				break
+			}
+
+			line, lineOk = t.handleKey(key)
+			if key == KeyCtrlD && lineOk == true {
+				return "", io.EOF
+			}
+			if key == KeyCtrlC {
+				t.remainder = nil
+				return "^C", fmt.Errorf("control-c break")
+			}
+		}
+		if len(rest) > 0 {
+			n := copy(t.inBuf[:], rest)
+			t.remainder = t.inBuf[:n]
+		} else {
+			t.remainder = nil
+		}
+		t.c.Write(t.outBuf)
+		t.outBuf = t.outBuf[:0]
+		if lineOk {
+			if t.echo { //&& len(line) > 0 {
+				// don't put passwords into history...
+				b := []byte(line)
+				h := make([]byte, len(b))
+				copy(h, b)
+				t.history = append(t.history, h)
+			}
+			return
+		}
+
+		// t.remainder is a slice at the beginning of t.inBuf
+		// containing a partial key sequence
+		readBuf := t.inBuf[len(t.remainder):]
+		var n int
+
+		t.lock.Unlock()
+		n, err = t.c.Read(readBuf)
+		t.lock.Lock()
+
+		if err != nil {
+			return "", err
+		}
+
+		t.remainder = t.inBuf[:n+len(t.remainder)]
+	}
+	panic("unreachable")
+}
+
+// SetPrompt sets the prompt to be used when reading subsequent lines.
+func (t *Terminal) SetPrompt(prompt string) {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	t.prompt = prompt
+}
+
+func (t *Terminal) SetSize(width, height int) {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	t.termWidth, t.termHeight = width, height
+}
+
+func (t *Terminal) SetHistory(h []string) {
+	// t.history = make([][]byte, len(h))
+	// for i := range h {
+	// 	t.history[i] = []byte(h[i])
+	// }
+	// //	t.historyIdx = len(h)
+}
+
+func (t *Terminal) GetHistory() (h []string) {
+	// h = make([]string, len(t.history))
+	// for i := range t.history {
+	// 	h[i] = string(t.history[i])
+	// }
+	return
+}
+
+type shell struct {
+	r io.Reader
+	w io.Writer
+}
+
+func (sh *shell) Read(data []byte) (n int, err error) {
+	return sh.r.Read(data)
+}
+
+func (sh *shell) Write(data []byte) (n int, err error) {
+	return sh.w.Write(data)
+}
+
+var oldState *State
+
+func (t *Terminal) ReleaseFromStdInOut() { // doesn't really need a receiver, but maybe oldState can be part of term one day
+	fd := int(os.Stdin.Fd())
+	Restore(fd, oldState)
+}
+
+func NewWithStdInOut() (term *Terminal, err error) {
+	fd := int(os.Stdin.Fd())
+	oldState, err = MakeRaw(fd)
+	if err != nil {
+		panic(err)
+	}
+	sh := &shell{r: os.Stdin, w: os.Stdout}
+	term = NewTerminal(sh, "")
+	return
+}