mercurial/txnutil.py
author Connor Sheehan <sheehan@mozilla.com>
Sat, 31 Mar 2018 10:21:39 -0400
changeset 37247 54b896f195d1
parent 31070 206532700213
child 43076 2372284d9457
permissions -rw-r--r--
stringutil: rename local email/names variables to their plural forms email and name variables are renamed to emails and names (respectively). This is because the email variable name shadows the email function within the stringutil module. Since we are renaming email, we also rename name for consistency. Differential Revision: https://phab.mercurial-scm.org/D3002

# txnutil.py - transaction related utilities
#
#  Copyright FUJIWARA Katsunori <foozy@lares.dti.ne.jp> 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)