fix(ext/node): windows cancel stdin read in line mode

[littledivy]

This patch fixes stdin read hanging on user input when switching tty mode on Windows

Fixes #21111

On Windows, when switching from line to raw mode:

• Cancel ongoing console read by writing a return keypress to its input buffer. This blocks the main thread until any ongoing read has been cancelled to prevent interference with the screen state.
• On the read thread, restore the cursor position to where it was before writing the enter, undoing its effect on the screen state.
• Restart reading and notify the main thread.

[satyarohith]

I don't have a Windows machine to test the change. I'll let David review the PR.

[bartlomieju]

Overall, looks good to me. Nice that there's a test. @dsherret can you try it out on your machine and see if it fixes the problem at hand?

[dsherret]

LGTM

[piscisaureus]

Probably the most terrible windows hack of all time.

I remember that in libuv we had to replace an already-terrible hack (calling ReadConsoleW against a duplicate of the CONIN$ handle; closing that handle would cancel the cooked read) that did the trick for Windows pre-Vista, but that stopped working when Windows 7 rolled around, leaving us with not other options.

Pretty appalling that more than a decade later there is still no solution on the horizon: microsoft/terminal#12143.

• On the read thread, restore the cursor position to where it was before writing the enter, undoing its effect on the screen state.

• Since in cooked mode the terminal will echo back any characters you write to it, you have to coordinate this action not just with reads but also with console writes.
• You have to consider what happens when the cursor position is at the very bottom of the buffer and the "enter", which will cause entire screen buffer to scroll while the cursor remains on the last line.

Final note: Best you can do is try it in practice and see that it works OK most of the time. It probably always will have edge cases where text ends up garbled. Only Microsoft could fix this (they won't though).

This patch fixes stdin read hanging on user input when switching tty mode on Windows

Fixes #21111

On Windows, when switching from line to raw mode:

• Cancel ongoing console read by writing a return keypress to its input buffer. This blocks the main thread until any ongoing read has been cancelled to prevent interference with the screen state.
• On the read thread, restore the cursor position to where it was before writing the enter, undoing its effect on the screen state.
• Restart reading and notify the main thread.

[littledivy]

Best you can do is try it in practice and see that it works OK most of the time.

Node v Deno comparision for some packages:

create-next-app

recording.mp4

crate-solid

solid.mp4

create-vite:

vite.mp4

Seems to work most of the time :)

[dsherret]

LGTM