revlog: avoid opening and closing the file for each cloned revision
The previous code was flushing files after each new revision, slowing things
down.
For exemple, with this change, the evolve repository can run
`hg debugupgraderepo --run --optimize re-delta-parent` in about 3.4s instead of
4.5 seconds.
# stack.py - Mercurial functions for stack definition
#
# Copyright Olivia Mackall <olivia@selenic.com> and other
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
def getstack(repo, rev=None):
"""return a sorted smartrev of the stack containing either rev if it is
not None or the current working directory parent.
The stack will always contain all drafts changesets which are ancestors to
the revision and are not merges.
"""
if rev is None:
rev = b'.'
revspec = b'only(%s) and not public() and not ::merge()'
revisions = repo.revs(revspec, rev)
revisions.sort()
return revisions