tvix/eval: EvalIO should allow reading a file in a more granular fashion

builtins.hashFile algo ./path/to/file returns a hex-encoded digest of the file.

We currrently can only use read_to_string, which reads the entire contents into memory.

We should extend this with an additional method that gives you an impl std::io::Read, so we don't have to read everything into memory.

We can provide a default implementation that does just use read_to_string() internally, and returns a Cursor over it, but implementations that can do better (like StdIO and TvixStoreIO) should probably do.

1. flokli changed the subject of this issue from "tvix/eval: EvalIO should have allow reading a file in a more granular fashion" to "tvix/eval: EvalIO should allow reading a file in a more granular fashion" at 2024-02-21T13·49+00

2. Took a pass at this in cl/11236. Ended up replacing read_to_string with open_file, then the callers can decide if they want to buffer into a string.

   cbrewster at 2024-03-23T00·09+00

3. I think this is sufficient for now. There's nothing inside nixlang requiring seeking.

   flokli at 2024-04-21T15·07+00

4. flokli closed this issue at 2024-04-21T15·07+00