mercurial/txnutil.py
author Boris Feld <boris.feld@octobus.net>
Wed, 29 Nov 2017 20:36:29 -0500
changeset 35208 1b758105b5c7
parent 31050 206532700213
child 43076 2372284d9457
permissions -rw-r--r--
lock: add a trylock method handling the timeout and messaging logic We are about to make the messages around lock more flexible. We move all the currently logic into a function in the lock module. We'll update the message scheme in the next changeset.

# 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)