view mercurial/utils/__init__.py @ 41615:328ca3b9e545

branchmap: encapsulate cache updating in the map itself

Rather than have a repository update the cache, move handling of cache updates
into the branchmap module, in the form of a custom mapping class.

This makes later performance improvements easier to handle too.

Differential Revision: https://phab.mercurial-scm.org/D5638