mercurial/txnutil.py
author Pierre-Yves David <pierre-yves.david@ens-lyon.org>
Tue, 21 Feb 2017 20:04:55 +0100
changeset 31123 df0a0734304a
parent 31050 206532700213
child 43076 2372284d9457
permissions -rw-r--r--
color: update main documentation Now that the feature no longer lives in the extension, we document it in the help of the core config. This include the new 'ui.color' option introduced in the previous changesets. As a result the color extensions can now be deprecated. This is a documentation patch only; color is still disabled by default.

# 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)