view mercurial/dirstateguard.py @ 33438:8056481caa81

codemod: simplify nested withs

This is the result of running:

  python codemod_nestedwith.py **/*.py

where codemod_nestedwith.py looks like this:

#!/usr/bin/env python
# codemod_nestedwith.py - codemod tool to rewrite nested with
#
# Copyright 2017 Facebook, Inc.
#
# 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, print_function

import sys

import redbaron

def readpath(path):
    with open(path) as f:
        return f.read()

def writepath(path, content):
    with open(path, 'w') as f:
        f.write(content)

def main(argv):
    if not argv:
        print('Usage: codemod_nestedwith.py FILES')

    for i, path in enumerate(argv):
        print('(%d/%d) scanning %s' % (i + 1, len(argv), path))
        changed = False
        red = redbaron.RedBaron(readpath(path))
        processed = set()
        for node in red.find_all('with'):
            if node in processed or node.type != 'with':
                continue
            top = node
            child = top[0]
            while True:
                if len(top) > 1 or child.type != 'with':
                    break
                # estimate line length after merging two "with"s
                new = '%swith %s:' % (top.indentation, top.contexts.dumps())
                new += ', %s' % child.contexts.dumps()
                # only do the rewrite if the end result is within 80 chars
                if len(new) > 80:
                    break
                processed.add(child)
                top.contexts.extend(child.contexts)
                top.value = child.value
                top.value.decrease_indentation(4)
                child = child[0]
                changed = True
        if changed:
            print('updating %s' % path)
            writepath(path, red.dumps())

if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))


Differential Revision: https://phab.mercurial-scm.org/D77

# dirstateguard.py - class to allow restoring dirstate after failure
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
#
# 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

from .i18n import _

from . import (
    error,
)

class dirstateguard(object):
    '''Restore dirstate at unexpected failure.

    At the construction, this class does:

    - write current ``repo.dirstate`` out, and
    - save ``.hg/dirstate`` into the backup file

    This restores ``.hg/dirstate`` from backup file, if ``release()``
    is invoked before ``close()``.

    This just removes the backup file at ``close()`` before ``release()``.
    '''

    def __init__(self, repo, name):
        self._repo = repo
        self._active = False
        self._closed = False
        self._suffix = '.backup.%s.%d' % (name, id(self))
        repo.dirstate.savebackup(repo.currenttransaction(), self._suffix)
        self._active = True

    def __del__(self):
        if self._active: # still active
            # this may occur, even if this class is used correctly:
            # for example, releasing other resources like transaction
            # may raise exception before ``dirstateguard.release`` in
            # ``release(tr, ....)``.
            self._abort()

    def close(self):
        if not self._active: # already inactivated
            msg = (_("can't close already inactivated backup: dirstate%s")
                   % self._suffix)
            raise error.Abort(msg)

        self._repo.dirstate.clearbackup(self._repo.currenttransaction(),
                                         self._suffix)
        self._active = False
        self._closed = True

    def _abort(self):
        self._repo.dirstate.restorebackup(self._repo.currenttransaction(),
                                           self._suffix)
        self._active = False

    def release(self):
        if not self._closed:
            if not self._active: # already inactivated
                msg = (_("can't release already inactivated backup:"
                         " dirstate%s")
                       % self._suffix)
                raise error.Abort(msg)
            self._abort()