feature: Deno.ttySize()

[sinclairzx81]

This PR implements the Deno.ttySize() API for obtaining the current terminal dimensions columns/rows. This update takes a dependency on the crossterm crate which should facilitate cross platform queries for current terminal dimensions.

PR is submitted for review and feedback with reference to issue #3456

[claassistantio]

All committers have signed the CLA.

[ry]

Nice work! I'm glad to see you were able to figure out how to add ops.

I'm not keen to take on new dependencies but crossterm looks good and will certainly be useful in the future. I'm going to now try to remove our termcolor = "1.0.5" and ansi_term = "0.11.0" and atty = "0.2.13".

Generally we prefer unit tests to integration tests because they run faster. I've edited your PR to do that. I've also marked it as unstable, since it's new.

[bartlomieju]

I wonder if enable_raw_mode will work with Tokio's stdio just like that 🤔 that would save us a lot of headache

[ry]

Actually I'm having second thoughts about crossterm because we have a lot of TTY crates and I would either like to reduce them to a single dependency or not add more. It doesn't seem like crossterm would allow reducing deps.

Here is a list of our current TTY crates:

• https://crates.io/crates/rustyline We use this for the REPL. But it seems like crossterm doesn't have very good readline support - Problems with input()::read_line() on version 5.1 crossterm-rs/crossterm#55 ... If we could replace rustyline with crossterm I would be all for it.
• https://crates.io/crates/atty a small utility that allows us to call the isatty syscall (and works on windows).. Doesn't seem crossterm provides this either.
• https://crates.io/crates/ansi_term https://crates.io/crates/termcolor stupidly we have two color crates. These could certainly be combined and it seems like crossterm does know how to do colors - so this is fine.

So I wonder if there is a smaller crate which can provide the functionality? Or can we just rip out the implementation from crossterm? We can certainly issue the ioctl ourselves without much difficulty https://stackoverflow.com/questions/1022957/getting-terminal-width-in-c

[sinclairzx81]

@ry Hi, thanks, yes, sorry, missed the unit test code in there, thanks for moving that.

Happy to keep an eye on this and help out on any enhancements down the road. I am guessing this is all fairly preliminary at this point, so happy to follow along with all design considerations on the tty api as things progress.

Many thanks

[ry]

Wow I totally forgot that we've already got term width/height in our code:

deno/cli/shell.rs

Line 398 in c824eb5

if libc::ioctl(libc::STDERR_FILENO, libc::TIOCGWINSZ, &mut winsize) < 0 {

I'm not sure what to do yet, but I'm more convinced that we need to clean up the TTY crate situation rather than adding a new dep.

[ry]

Needs more investigation

[ry]

Thanks for the patch @sinclairzx81 but I'm going to close without merge. I don't want to add this crossterm dep. This ttySize op is definitely desirable, but I think we can achieve it (at least on unix) with a single line as I gave above.

[apatrida]

@ry it seems like you'll need something like CrossTerm (or similar code) for node tty support #5392. Resize event can be had via signals already, but we are missing columns, rows that this patch was focusing on, and clearLine, clearScreenDown, cursorTo, moveCursor, getColorDepth, hasColors (covered by noColor?), ... Some are just ANSI sequences, but not all.

[Yamboy1]

Any update on this? My current deno readline-esque implementation for my shell is broken when you hit the edge of the terminal, not sure if I can go any further without checking the size of the terminal as well as resize events

https://github.com/Yamboy1/denosh