view mercurial/txnutil.py @ 35495:07fdac1d5c66

repoview: add a new filtername for accessing hidden commits

This patch adds a new filter 'visible-hidden' for repository and will be used to
return a repo object with user passed revisions unhidden. Unlike the
directaccess extension in fb-hgext and previous series adding the functionality,
this time we introduce only one new filter as whether to warn user or not is
handled by scmutil.unhidehashlikerevs().

Differential Revision: https://phab.mercurial-scm.org/D1734

# 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)