hg-core: make parse_dirstate return references rather than update hashmaps
Returing a vec is faster than updating a hashmap when the hashmap is not needed
like in `hg files` which just list tracked files.
Returning references avoid copying data when not needed improving performence
for large repositories.
Differential Revision: https://phab.mercurial-scm.org/D8861
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install::
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing::
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See https://mercurial-scm.org/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.