// 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 term
import (
"bytes"
"io"
"runtime"
"strconv"
"sync"
"unicode/utf8"
)
// 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 (in
// bytes, as an index into |line|). If it returns ok=false, the key
// press is processed normally. Otherwise it returns a replacement line
// and the new cursor position.
AutoCompleteCallback func(line string, pos int, key rune) (newLine string, newPos int, ok bool)
// 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 []rune
// line is the current line being entered.
line []rune
// pos is the logical position of the cursor in line
pos int
// echo is true if local echo is enabled
echo bool
// pasteActive is true iff there is a bracketed paste operation in
// progress.
pasteActive 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
// history contains previously entered commands so that they can be
// accessed with the up and down keys.
history stRingBuffer
// historyIndex stores the currently accessed history entry, where zero
// means the immediately previous entry.
historyIndex int
// When navigating up and down the history it's possible to return to
// the incomplete, initial line. That value is stored in
// historyPending.
historyPending string
}
// 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: []rune(prompt),
termWidth: 80,
termHeight: 24,
echo: true,
historyIndex: -1,
}
}
const (
keyCtrlC = 3
keyCtrlD = 4
keyCtrlU = 21
keyEnter = '\r'
keyEscape = 27
keyBackspace = 127