Treat UnexpectedEof as Disconnect

[tecywiz121]

After the other end of a unix domain socket or a pipe disconnects, calls to read_exact will return an UnexpectedEof error.

I believe that this should be treated as an ErrorKind::Disconnect and not a generic ErrorKind::Failure.

[dwrensha]

Thanks!

In the context of the RPC system, I agree that ErrorKind::Disconnect seems appropriate for this sort of error. But what if the (truncated) message is being read from disk? ErrorKind::Disconnect seems inappropriate in that case.

Maybe what we should really be doing is looking into wrapping errors more faithfully, as e.g. the failure crate might allow us to do.

[tecywiz121]

What would ErrorKind::Disconnect mean when reading from disk? That the file was deleted?

I've been using snafu lately, and been enjoying it, but you can avoid pulling in an external crate if all you want to do is wrap the error type: just add a variant with the error type and implement std::error::Error.

[dwrensha]

I've added a try_read_message() function in 18c2e0c. The idea is that you can call this function in a loop and stop when it return None, which means EOF. Does that address your concern?

[tecywiz121]

I'm no longer working on the project using this crate, but @JoelScarfone will probably have an opinion.