view mercurial/txnutil.py @ 34781:fe987d0b9e1e

registrar: add support for storing the type of command in func object

This patch adds support for storing the type of command which is going to run in
the func object. For this it does the following:

1) Add three possible values as attributes to the registrar.command class
2) Add a new argument to registrar.command._doregister function
3) Add a new attribute cmdtype to the func object

The type of command will be helpful in deciding what level of access on hidden
commits it can has.

Differential Revision: https://phab.mercurial-scm.org/D736

# 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)