nodemap: only use persistent nodemap for non-inlined revlog Revlog are inlined while they are small (to avoid having too many file to deal with). The persistent nodemap will only provides a significant boost for large enough revlog index. So it does not make sens to add an extra file to store nodemap for small revlog. We could consider inclining the nodemap data inside the revlog itself, but the benefit is unclear so let it be an adventure for another time. Differential Revision: https://phab.mercurial-scm.org/D7837

nodemap: add a function to read the data from disk This changeset is small and mostly an excuse to introduce an API function reading the data from disk. Differential Revision: https://phab.mercurial-scm.org/D7836

nodemap: write nodemap data on disk Let us start writing data on disk (so that we can read it from there later). This series of changeset is going to focus first on having data on disk and updating it. Right now the data is written right next to the revlog data, in the store. We might move it to cache (with proper cache validation mechanism) later, but for now revlog have a storevfs instance and it is simpler to us it. The right location for this data is not the focus of this series. Differential Revision: https://phab.mercurial-scm.org/D7835

nodemap: have some python code writing a nodemap in persistent binary form This python code aims to be as "simple" as possible. It is a reference implementation of the data we are going to write on disk (and possibly, later a way for pure python install to make sure the on disk data are up to date). It is not optimized for performance and rebuild the full data structure from the index every time. This is a stepping stone toward a persistent nodemap on disk. Differential Revision: https://phab.mercurial-scm.org/D7834

cleanup: re-run black on the codebase Looks like a few patches have landed without having been blackened. I strongly suspect I should write a patch for baymax that blackens things on the way in... # skip-blame automatic formatting Differential Revision: https://phab.mercurial-scm.org/D8104

rust-re2: add wrapper for calling Re2 from Rust This assumes that Re2 is installed following Google's guide. I am not sure how we want to integrate it in the project, but I think a follow-up patch would be more appropriate for such work. As it stands, *not* having Re2 installed results in a compilation error, which is a problem as it breaks install compatibility. Hence, this is gated behind a non-default `with-re2` compilation feature. Differential Revision: https://phab.mercurial-scm.org/D7910