view mercurial/txnutil.py @ 42144:013de80bf90e

recover: add a --[no-]verify flag

For trivial cases, the cost of the verify run after `hg recover` is getting in
the way. In addition for very large repositories, the cost is simply too high
to be paid, making `hg recover` an unusable commands.

We introduce a --verify flag, set by default. If is automatically associated
with a --no-verify flag that one can use to skip the verify step.

We might consider changing the default behavior in the future. However this is
out of scope for this series.

# 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)