linelog: add a Python implementation of the linelog datastructure...
linelog: add a Python implementation of the linelog datastructure
This datastructure was originally developed by Jun Wu at Facebook,
inspired by SCCS weaves. It's useful as a cache for blame information,
but also is the magic that makes `hg absorb` easy to implement. In
service of importing the code to Mercurial, I wanted to actually
/understand/ it, and once I did I decided to take a run at
implementing it.
The help/internals/linelog.txt document is the README from Jun Wu's
implementaiton. It all applies to our linelog implementation.
Differential Revision:
https://phab.mercurial-scm.org/D3990
