tty → readline ansi/vt100 migration

[TooTallNate]

This is the result of a discussion @piscisaureus, @isaacs and I were having. The overall goal here is to make readline more interoperable with other node Streams like say a net.Socket instance, in "enabled" mode.

There's a lot going on here, I'll try to break it down:

• move tty.setRawMode() to tty.ReadStream's prototype
• remove tty.getWindowSize() and tty.setWindowSize(), redundant/incomplete
• add a tty.ReadStream#isRaw flag (so process.stdin.isRaw). gets set when setRawMode() is called.
• remove use of tty module in readline module.
• move the "keypress" logic from tty → readline
• move WriteStream#cursorTo from tty → readline
• move WriteStream#moveTo from tty → readline
• move WriteStream#clearLine from tty → readline
• move the "SIGWINCH" handling code from readline → tty, make process.stdout emit a "resize" event
• add process.stdout.rows and process.stdout.columns; deprecate process.stdout.getWindowSize()

[TooTallNate]

So this pull + #2919 makes this code work with this "full-featured" client:

var repl = require('repl')
var net = require('net')

net.createServer(function (socket) {

  // hack #1
  socket.isTTY = true

  var r = repl.start('socket repl> ', socket)
  r.on('exit', function () {
    console.error('repl exit event, closing socket')
    socket.end()
  })
}).listen(1337)

Which leaves one final ugly wart: isTTY. readline should not be checking this property.

I personally think we should change readline.Interface and repl.REPLServer to both accept an Options object. That way you would could explicitly specify "enabled: true" (maybe a better name "immediate"?), and "colors: true" and this wouldn't be so hacky.

So maybe, in the end, we could write code like this:

var repl = require('repl')
var net = require('net')

net.createServer(function (socket) {
  repl.start({
      prompt: 'repl> '
    , socket: socket
    , enabled: true
    , useGlobal: false
  }).on('exit', function () {
    socket.end()
  })
}).listen(1337)

But these changes belong in another pull request I think...

[ghost]

Awesome, this is all the things I did for my mintty hack and more to allow it to spit out ansi to a Socket. This raises the issue with window size though.

[TooTallNate]

So I ended up just adding explicit support for the enabled option of the readline interface, thus removing the final ugly wart: isTTY from readline. So now that code is clean as far as responsibilities are concerned.

So basically, this code actually works!!!

var repl = require('repl')
var net = require('net')

net.createServer(function (socket) {
  repl.start({
      socket: socket
    , enabled: true
  }).on('exit', function () {
    socket.end()
  })
}).listen(1337)

[TooTallNate]

/cc @piscisaureus @isaacs @bnoordhuis @mranney

[rlidwka]

Awesome, this is all the things I did for my mintty hack and more to allow it to spit out ansi to a Socket. This raises the issue with window size though.

Yeah, i did smth simular for my telnet server.

+1 for resize event, will be useful.

@TooTallNate but SIGWINCH is for stdout only (not for all writable streams), right? It means that it probably should be written like that:

  if (self === process.stdout) process.on('SIGWINCH', function() {
    var winSize = self._handle.getWindowSize();
    self.columns = winSize[0];
    self.rows = winSize[1];
    self.emit('resize', winSize);
 });

I dont know if it works though. I had an issue recently when resizing main window affected telnet windows.

[rlidwka]

Some tests have failed with this. Is that critical?

=== release test-debugger-repl ===                                         
Path: simple/test-debugger-repl
 != /break in .*:11/
Command: out/Release/node /home/alex/node-work-2/node/test/simple/test-debugger-repl.js

=== release test-debugger-repl-utf8 ===                                    
Path: simple/test-debugger-repl-utf8
 != /break in .*:11/
Command: out/Release/node /home/alex/node-work-2/node/test/simple/test-debugger-repl-utf8.js

[bnoordhuis]

Some tests have failed with this. Is that critical?

No. Those tests have been failing consistently for weeks now, maybe longer. :-/