view mercurial/txnutil.py @ 32320:0e29ce16ec38

diffstat: properly count lines starting in '--' or '++' (issue5479)

Lines that start in '--' or '++' were previously not counted
as deletions or additions in diffstat, resulting in incorrect
addition/deletion counts.  The bug was present if the start
of the line, combined with the diff character resulted
in '---' or '+++'.

diffstatdata will now track, for each file, if it has moved
pas the header section by looking for a line beginning with
'@@'.  Once that has happened, lines beginning with '-'
or '+' will be counted for deletions and additions.  Once a
line beginning with 'diff' is found, the process starts over.

# 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)