##// END OF EJS Templates
rust-nodemap: core implementation for shortest...
rust-nodemap: core implementation for shortest In this implementation, we just make `lookup()` return also the number of steps that have been needed to come to a conclusion from the nodetree data, and `validate_candidate()` takes care of the special cases related to `NULL_NODE`. This way of doing minimizes code duplication, but it means that the comparatively slower finding of first non zero nybble will run for all calls to `find()` where it is not needed. Still running on the file generated for the mozilla-central repository, it seems indeed that we now get more ofter 320 ns than 310. The odds that this could have a significant impact on real life Mercurial performance are still looking low. Let's wait for actual benchmark runs to see if an optimization is needed here. Differential Revision: https://phab.mercurial-scm.org/D7819
Georges Racinet -
r44872:5ac1eecc default
Show More
Name Size Modified Last Commit Author
/ rust
.cargo
chg
hg-core
hg-cpython
hg-direct-ffi
hgcli
Cargo.lock Loading ...
Cargo.toml Loading ...
README.rst Loading ...

Mercurial Rust Code

This directory contains various Rust code for the Mercurial project. Rust is not required to use (or build) Mercurial, but using it improves performance in some areas.

There are currently three independent rust projects: - chg. An implementation of chg, in rust instead of C. - hgcli. A experiment for starting hg in rust rather than in python,

by linking with the python runtime. Probably meant to be replaced by PyOxidizer at some point.
  • hg-core (and hg-cpython/hg-directffi): implementation of some functionality of mercurial in rust, e.g. ancestry computations in revision graphs or pull discovery. The top-level Cargo.toml file defines a workspace containing these crates.

Using hg-core

Local use (you need to clean previous build artifacts if you have built without rust previously):

$ HGWITHRUSTEXT=cpython make local # to use ./hg
$ HGWITHRUSTEXT=cpython make tests # to run all tests
$ (cd tests; HGWITHRUSTEXT=cpython ./run-tests.py) # only the .t
$ ./hg debuginstall | grep rust # to validate rust is in use
checking module policy (rust+c-allow)

Setting HGWITHRUSTEXT to other values like true is deprecated and enables only a fraction of the rust code.

Developing hg-core

Simply run:

$ cargo build --release

It is possible to build without --release, but it is not recommended if performance is of any interest: there can be an order of magnitude of degradation when removing --release.

For faster builds, you may want to skip code generation:

$ cargo check

You can run only the rust-specific tests (as opposed to tests of mercurial as a whole) with:

$ cargo test --all