mercurial/txnutil.py

hgweb: add diffs to the json changeset template

While it's possible to get the diff for each file individually via an
obscure url that I'm not even sure is documented, (e.g.
diff/{rev}/{filename}?style=json ), it is more convenient to provide
the full diff from the changeset view. This is already normally
computed for other non-JSON templates, so it seems like an oversight
to omit it for the JSON one.

The output format is a bit unwieldy but it's consistent with the
existing format output by the aforementioned obscure url.

# 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(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)