rust-dirstate: add rust implementation of `parse_dirstate` and `pack_dirstate`...
rust-dirstate: add rust implementation of `parse_dirstate` and `pack_dirstate`
Working towards the goal of having a complete Rust implementation of
`hg status`, these two utils are a first step of many to be taken
to improve performance and code maintainability.
Two dependencies have been added: `memchr` and `byteorder`.
Both of them have been written by reputable community members and are
very mature crates.
The Rust code will often need to use their byte-oriented functions.
A few unit tests have been added and may help future development and debugging.
In a future patch that uses `parse_dirstate` to stat the working tree in
parallel - which neither the Python nor the C implementations do - actual
performance improvements will be seen for larger repositories.
Differential Revision:
https://phab.mercurial-scm.org/D6348
