Cathode Progress Report - February 2024

[alexrp]

This is part of a series of progress reports that are posted with a monthly-ish cadence when there's notable progress made on the project.

v0.12.42 Release

v0.12.42 saw some major improvements to terminal drivers and child process APIs.

The biggest change here is the introduction of a new Vezel.Cathode.Native library written in C (#43). This library now contains all platform-specific interop code (sans #141) for terminal drivers. This makes it easier for us to port Cathode to new platforms in the future and cuts down on some code duplication we had for Unix platforms. But most importantly, it comes with these user-facing improvements:

• We now restore terminal configuration properly on shutdown without the use of Vezel.Cathode.Hosting. As a result, that package has been discontinued.
  • Note that this is still a best-effort feature. We don't currently attempt to restore the terminal configuration in case of native crashes (e.g. SIGSEGV or SIGILL), and there's literally no chance for us to do so for SIGKILL.
• We now support cancellation for raw reads on Windows (see Support cooked input cancellation on Windows #63).
  • Cancellation for cooked reads is still not fully functional due to Need a reasonable way to either cancel ReadConsole or poll for text input microsoft/terminal#12143.
• We now support cancellation for writes on Unix, in addition to our existing support for read cancellation.

Note that Vezel.Cathode.Native is not yet available on musl-based systems such as Alpine Linux. See #142 for details. This means that if you're using Cathode on such a system, you will want to hold off on upgrading for now.

A number of improvements were made to the child process APIs:

• We added some extra Run() and RunIn() convenience methods on ChildProcess.
• We redesigned exception handling so that ChildProcessException is thrown if something goes wrong with starting or killing a process, while the new ChildProcessErrorException (deriving from ChildProcessException) is thrown for a non-zero exit code if ChildProcessBuilder.ThrowOnError is set.
• We changed ChildProcess.Kill() to handle SystemException instead of the more specific InvalidOperationException (ChildProcess.Kill() can let internal exceptions through #139).
  • In some esoteric cases, if an underlying DuplicateHandle call failed, a variety of exceptions (deriving from SystemException) could be thrown. None of these are interesting to the caller.
• We changed ChildProcessReader to not unnecessarily bubble up IOExceptions when the child process closes the pipe (ChildProcessReader can bubble up internal exceptions to ChildProcess.Completion #138).
• We fixed ChildProcessReader to handle cancellation of the child process correctly.
  • Previously, it could get stuck in its read loop when cancellation was requested.

Finally, we added Black Box, Contour, Guake, Tilix, tmux, Xfce Terminal, and Yakuake to the list of supported terminal emulators (#134).

Future Plans

There are no changes to our plans for v1.0 and v2.0 since #136.