D2057: translate base85.c into rust code

[indygreg (Gregory Szorc)]

indygreg added a comment.


  To be honest, we're not yet sure what we'll decide for the Python -> Rust bridge. The problem is summarized in the `Rust <=> Python Interop` section on https://www.mercurial-scm.org/wiki/OxidationPlan.
  
  I suspect at some level we'll need a CPython extension for CPython for performance reasons (especially for high volume function calls). PyPy obviously uses CFFI. I think the ideal outcome is we can write Rust that exposes a C API and use CFFI natively on PyPy and something like `cbindgen` + `Milksnake` to auto-generate a CPython extension that acts as a wrapper around the C API exposed by Rust. I'm not sure if anyone has invented this exact wheel yet. If not, it's probably faster to use `rust-cpython`. Maybe several months from now we have enough Rust and maintaining `rust-cpython` is painful enough that we pursue the auto-generated CPython extension route.
  
  What I'm trying to say is you have a green field to explore! But at this juncture, perfect is the enemy of done. We'll be happy with any forward progress, even failed experiments.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D2057

To: Ivzhh, #hg-reviewers
Cc: krbullock, indygreg, durin42, kevincox, mercurial-devel