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Mini Shell
Mini Shell
'use strict';
const {
ArrayPrototypeSlice,
ArrayPrototypeSort,
RegExpPrototypeExec,
StringFromCharCode,
StringPrototypeCharCodeAt,
StringPrototypeCodePointAt,
StringPrototypeSlice,
StringPrototypeToLowerCase,
Symbol,
} = primordials;
const kUTF16SurrogateThreshold = 0x10000; // 2 ** 16
const kEscape = '\x1b';
const kSubstringSearch = Symbol('kSubstringSearch');
function CSI(strings, ...args) {
let ret = `${kEscape}[`;
for (let n = 0; n < strings.length; n++) {
ret += strings[n];
if (n < args.length)
ret += args[n];
}
return ret;
}
CSI.kEscape = kEscape;
CSI.kClearToLineBeginning = CSI`1K`;
CSI.kClearToLineEnd = CSI`0K`;
CSI.kClearLine = CSI`2K`;
CSI.kClearScreenDown = CSI`0J`;
// TODO(BridgeAR): Treat combined characters as single character, i.e,
// 'a\u0301' and '\u0301a' (both have the same visual output).
// Check Canonical_Combining_Class in
// http://userguide.icu-project.org/strings/properties
function charLengthLeft(str, i) {
if (i <= 0)
return 0;
if ((i > 1 &&
StringPrototypeCodePointAt(str, i - 2) >= kUTF16SurrogateThreshold) ||
StringPrototypeCodePointAt(str, i - 1) >= kUTF16SurrogateThreshold) {
return 2;
}
return 1;
}
function charLengthAt(str, i) {
if (str.length <= i) {
// Pretend to move to the right. This is necessary to autocomplete while
// moving to the right.
return 1;
}
return StringPrototypeCodePointAt(str, i) >= kUTF16SurrogateThreshold ? 2 : 1;
}
/*
Some patterns seen in terminal key escape codes, derived from combos seen
at http://www.midnight-commander.org/browser/lib/tty/key.c
ESC letter
ESC [ letter
ESC [ modifier letter
ESC [ 1 ; modifier letter
ESC [ num char
ESC [ num ; modifier char
ESC O letter
ESC O modifier letter
ESC O 1 ; modifier letter
ESC N letter
ESC [ [ num ; modifier char
ESC [ [ 1 ; modifier letter
ESC ESC [ num char
ESC ESC O letter
- char is usually ~ but $ and ^ also happen with rxvt
- modifier is 1 +
(shift * 1) +
(left_alt * 2) +
(ctrl * 4) +
(right_alt * 8)
- two leading ESCs apparently mean the same as one leading ESC
*/
function* emitKeys(stream) {
while (true) {
let ch = yield;
let s = ch;
let escaped = false;
const key = {
sequence: null,
name: undefined,
ctrl: false,
meta: false,
shift: false,
};
if (ch === kEscape) {
escaped = true;
s += (ch = yield);
if (ch === kEscape) {
s += (ch = yield);
}
}
if (escaped && (ch === 'O' || ch === '[')) {
// ANSI escape sequence
let code = ch;
let modifier = 0;
if (ch === 'O') {
// ESC O letter
// ESC O modifier letter
s += (ch = yield);
if (ch >= '0' && ch <= '9') {
modifier = (ch >> 0) - 1;
s += (ch = yield);
}
code += ch;
} else if (ch === '[') {
// ESC [ letter
// ESC [ modifier letter
// ESC [ [ modifier letter
// ESC [ [ num char
s += (ch = yield);
if (ch === '[') {
// \x1b[[A
// ^--- escape codes might have a second bracket
code += ch;
s += (ch = yield);
}
/*
* Here and later we try to buffer just enough data to get
* a complete ascii sequence.
*
* We have basically two classes of ascii characters to process:
*
*
* 1. `\x1b[24;5~` should be parsed as { code: '[24~', modifier: 5 }
*
* This particular example is featuring Ctrl+F12 in xterm.
*
* - `;5` part is optional, e.g. it could be `\x1b[24~`
* - first part can contain one or two digits
* - there is also special case when there can be 3 digits
* but without modifier. They are the case of paste bracket mode
*
* So the generic regexp is like /^(?:\d\d?(;\d)?[~^$]|\d{3}~)$/
*
*
* 2. `\x1b[1;5H` should be parsed as { code: '[H', modifier: 5 }
*
* This particular example is featuring Ctrl+Home in xterm.
*
* - `1;5` part is optional, e.g. it could be `\x1b[H`
* - `1;` part is optional, e.g. it could be `\x1b[5H`
*
* So the generic regexp is like /^((\d;)?\d)?[A-Za-z]$/
*
*/
const cmdStart = s.length - 1;
// Skip one or two leading digits
if (ch >= '0' && ch <= '9') {
s += (ch = yield);
if (ch >= '0' && ch <= '9') {
s += (ch = yield);
if (ch >= '0' && ch <= '9') {
s += (ch = yield);
}
}
}
// skip modifier
if (ch === ';') {
s += (ch = yield);
if (ch >= '0' && ch <= '9') {
s += yield;
}
}
/*
* We buffered enough data, now trying to extract code
* and modifier from it
*/
const cmd = StringPrototypeSlice(s, cmdStart);
let match;
if ((match = RegExpPrototypeExec(/^(?:(\d\d?)(?:;(\d))?([~^$])|(\d{3}~))$/, cmd))) {
if (match[4]) {
code += match[4];
} else {
code += match[1] + match[3];
modifier = (match[2] || 1) - 1;
}
} else if (
(match = RegExpPrototypeExec(/^((\d;)?(\d))?([A-Za-z])$/, cmd))
) {
code += match[4];
modifier = (match[3] || 1) - 1;
} else {
code += cmd;
}
}
// Parse the key modifier
key.ctrl = !!(modifier & 4);
key.meta = !!(modifier & 10);
key.shift = !!(modifier & 1);
key.code = code;
// Parse the key itself
switch (code) {
/* xterm/gnome ESC [ letter (with modifier) */
case '[P': key.name = 'f1'; break;
case '[Q': key.name = 'f2'; break;
case '[R': key.name = 'f3'; break;
case '[S': key.name = 'f4'; break;
/* xterm/gnome ESC O letter (without modifier) */
case 'OP': key.name = 'f1'; break;
case 'OQ': key.name = 'f2'; break;
case 'OR': key.name = 'f3'; break;
case 'OS': key.name = 'f4'; break;
/* xterm/rxvt ESC [ number ~ */
case '[11~': key.name = 'f1'; break;
case '[12~': key.name = 'f2'; break;
case '[13~': key.name = 'f3'; break;
case '[14~': key.name = 'f4'; break;
/* paste bracket mode */
case '[200~': key.name = 'paste-start'; break;
case '[201~': key.name = 'paste-end'; break;
/* from Cygwin and used in libuv */
case '[[A': key.name = 'f1'; break;
case '[[B': key.name = 'f2'; break;
case '[[C': key.name = 'f3'; break;
case '[[D': key.name = 'f4'; break;
case '[[E': key.name = 'f5'; break;
/* common */
case '[15~': key.name = 'f5'; break;
case '[17~': key.name = 'f6'; break;
case '[18~': key.name = 'f7'; break;
case '[19~': key.name = 'f8'; break;
case '[20~': key.name = 'f9'; break;
case '[21~': key.name = 'f10'; break;
case '[23~': key.name = 'f11'; break;
case '[24~': key.name = 'f12'; break;
/* xterm ESC [ letter */
case '[A': key.name = 'up'; break;
case '[B': key.name = 'down'; break;
case '[C': key.name = 'right'; break;
case '[D': key.name = 'left'; break;
case '[E': key.name = 'clear'; break;
case '[F': key.name = 'end'; break;
case '[H': key.name = 'home'; break;
/* xterm/gnome ESC O letter */
case 'OA': key.name = 'up'; break;
case 'OB': key.name = 'down'; break;
case 'OC': key.name = 'right'; break;
case 'OD': key.name = 'left'; break;
case 'OE': key.name = 'clear'; break;
case 'OF': key.name = 'end'; break;
case 'OH': key.name = 'home'; break;
/* xterm/rxvt ESC [ number ~ */
case '[1~': key.name = 'home'; break;
case '[2~': key.name = 'insert'; break;
case '[3~': key.name = 'delete'; break;
case '[4~': key.name = 'end'; break;
case '[5~': key.name = 'pageup'; break;
case '[6~': key.name = 'pagedown'; break;
/* putty */
case '[[5~': key.name = 'pageup'; break;
case '[[6~': key.name = 'pagedown'; break;
/* rxvt */
case '[7~': key.name = 'home'; break;
case '[8~': key.name = 'end'; break;
/* rxvt keys with modifiers */
case '[a': key.name = 'up'; key.shift = true; break;
case '[b': key.name = 'down'; key.shift = true; break;
case '[c': key.name = 'right'; key.shift = true; break;
case '[d': key.name = 'left'; key.shift = true; break;
case '[e': key.name = 'clear'; key.shift = true; break;
case '[2$': key.name = 'insert'; key.shift = true; break;
case '[3$': key.name = 'delete'; key.shift = true; break;
case '[5$': key.name = 'pageup'; key.shift = true; break;
case '[6$': key.name = 'pagedown'; key.shift = true; break;
case '[7$': key.name = 'home'; key.shift = true; break;
case '[8$': key.name = 'end'; key.shift = true; break;
case 'Oa': key.name = 'up'; key.ctrl = true; break;
case 'Ob': key.name = 'down'; key.ctrl = true; break;
case 'Oc': key.name = 'right'; key.ctrl = true; break;
case 'Od': key.name = 'left'; key.ctrl = true; break;
case 'Oe': key.name = 'clear'; key.ctrl = true; break;
case '[2^': key.name = 'insert'; key.ctrl = true; break;
case '[3^': key.name = 'delete'; key.ctrl = true; break;
case '[5^': key.name = 'pageup'; key.ctrl = true; break;
case '[6^': key.name = 'pagedown'; key.ctrl = true; break;
case '[7^': key.name = 'home'; key.ctrl = true; break;
case '[8^': key.name = 'end'; key.ctrl = true; break;
/* misc. */
case '[Z': key.name = 'tab'; key.shift = true; break;
default: key.name = 'undefined'; break;
}
} else if (ch === '\r') {
// carriage return
key.name = 'return';
key.meta = escaped;
} else if (ch === '\n') {
// Enter, should have been called linefeed
key.name = 'enter';
key.meta = escaped;
} else if (ch === '\t') {
// tab
key.name = 'tab';
key.meta = escaped;
} else if (ch === '\b' || ch === '\x7f') {
// backspace or ctrl+h
key.name = 'backspace';
key.meta = escaped;
} else if (ch === kEscape) {
// escape key
key.name = 'escape';
key.meta = escaped;
} else if (ch === ' ') {
key.name = 'space';
key.meta = escaped;
} else if (!escaped && ch <= '\x1a') {
// ctrl+letter
key.name = StringFromCharCode(
StringPrototypeCharCodeAt(ch) + StringPrototypeCharCodeAt('a') - 1,
);
key.ctrl = true;
} else if (RegExpPrototypeExec(/^[0-9A-Za-z]$/, ch) !== null) {
// Letter, number, shift+letter
key.name = StringPrototypeToLowerCase(ch);
key.shift = RegExpPrototypeExec(/^[A-Z]$/, ch) !== null;
key.meta = escaped;
} else if (escaped) {
// Escape sequence timeout
key.name = ch.length ? undefined : 'escape';
key.meta = true;
}
key.sequence = s;
if (s.length !== 0 && (key.name !== undefined || escaped)) {
/* Named character or sequence */
stream.emit('keypress', escaped ? undefined : s, key);
} else if (charLengthAt(s, 0) === s.length) {
/* Single unnamed character, e.g. "." */
stream.emit('keypress', s, key);
}
/* Unrecognized or broken escape sequence, don't emit anything */
}
}
// This runs in O(n log n).
function commonPrefix(strings) {
if (strings.length === 0) {
return '';
}
if (strings.length === 1) {
return strings[0];
}
const sorted = ArrayPrototypeSort(ArrayPrototypeSlice(strings));
const min = sorted[0];
const max = sorted[sorted.length - 1];
for (let i = 0; i < min.length; i++) {
if (min[i] !== max[i]) {
return StringPrototypeSlice(min, 0, i);
}
}
return min;
}
module.exports = {
charLengthAt,
charLengthLeft,
commonPrefix,
emitKeys,
kSubstringSearch,
CSI,
};
Zerion Mini Shell 1.0