D476: util: add an mmapread method

[indygreg (Gregory Szorc)]

indygreg added inline comments.

INLINE COMMENTS

> simonfar wrote in util.py:413
> As per comment on https://phab.mercurial-scm.org/D477 - do we want this to be raw, or `buffer(mmap.mmap(...`?

Some consumers may want file like objects. Others may want buffers.

Whatever you do, I would rename the function to what it actually does. e.g. ``mmapfd`` or ``mmapbuffer``.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D476

To: mbthomas, #fbhgext, #hg-reviewers
Cc: indygreg, simonfar, mercurial-devel