copies: introduce a basic Rust function for `combine_changeset_copies`...
copies: introduce a basic Rust function for `combine_changeset_copies`
This new function mirror the python code. This first implementation does a lot
of data copies and is therefore quite slow. However my goal here is to create a
simple "frame" from where to start adding optimization.
This patch focus on the `hg-core` part of this work. Coming patches will do the
necessary `hg-cpython` work to be able to use this from Python.
Differential Revision:
https://phab.mercurial-scm.org/D9297
