mercurial/txnutil.py

hidden: change _domainancestors() to _revealancestors()

This change makes the function actually reveal the ancestors by
removing them from the hidden set. This prepares for further
simplification.

Note that the function will now only reveal contiguous chains of
hidden revisions, but that's fine because we always pass it an
immediate child of any revision that should be revealed (or the
revision itself).

This doesn't seem to have much impact on "perfvolatilesets".

Before:
! obsolete
! wall 0.004672 comb 0.010000 user 0.010000 sys 0.000000 (best of 590)
! visible
! wall 0.008936 comb 0.010000 user 0.010000 sys 0.000000 (best of 322)

After:
! obsolete
! wall 0.004903 comb 0.000000 user 0.000000 sys 0.000000 (best of 535)
! visible
! wall 0.008913 comb 0.010000 user 0.010000 sys 0.000000 (best of 300)

# txnutil.py - transaction related utilities
#
#  Copyright FUJIWARA Katsunori <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import errno

from . import (
    encoding,
)

def mayhavepending(root):
    '''return whether 'root' may have pending changes, which are
    visible to this process.
    '''
    return root == encoding.environ.get('HG_PENDING')

def trypending(root, vfs, filename, **kwargs):
    '''Open  file to be read according to HG_PENDING environment variable

    This opens '.pending' of specified 'filename' only when HG_PENDING
    is equal to 'root'.

    This returns '(fp, is_pending_opened)' tuple.
    '''
    if mayhavepending(root):
        try:
            return (vfs('%s.pending' % filename, **kwargs), True)
        except IOError as inst:
            if inst.errno != errno.ENOENT:
                raise
    return (vfs(filename, **kwargs), False)