repository: introduce constant for treemanifest requirement and use it
In future we will like to much cleaner logic around which requirement is for
working copy and which can go in store. To start with that, we first need to
de-clutter the requirement values spread around and replace them with constants.
Differential Revision: https://phab.mercurial-scm.org/D8916
# 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(b'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(b'%s.pending' % filename, **kwargs), True)
except IOError as inst:
if inst.errno != errno.ENOENT:
raise
return (vfs(filename, **kwargs), False)