view mercurial/dirstateguard.py @ 42897:d7304434390f

changegroup: move message about added changes to transaction summary

Before that, applying multiple changegroups in the same transaction issued the
message multiple time. This result in a confusing output:

    adding changesets
    adding manifests
    adding file changes
    added 32768 changesets with 60829 changes to 2668 files
    adding changesets
    adding manifests
    adding file changes
    added 8192 changesets with 16885 changes to 1553 files
    adding changesets
    adding manifests
    adding file changes
    added 1020 changesets with 1799 changes to 536 files
    adding changesets
    adding manifests
    ...

Instead, we now only issue the message once at the end of the transaction,
summing up all added changesets, changes and files. The line is identical, but
happens sightly later in the output.

There are other suboptimal behavior around issue multiple changegroup (eg:
progress bar). We'll cover them later.

This impact of lot of test as one would expect, but a two pass check show they
are just the order change we expected.

To deal with "under the hood" bundle application by internal code, we had to
take a slightly hacky move. We could clean that up with a more official way to
enter "under the hood" section, however I want to keep this series simple to get
it landed. This kind of change have a very high bit rot rate since it impact a
lot of test output.

# 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,
    narrowspec,
    util,
)

class dirstateguard(util.transactional):
    '''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._backupname = 'dirstate.backup.%s.%d' % (name, id(self))
        self._narrowspecbackupname = ('narrowspec.backup.%s.%d' %
                                      (name, id(self)))
        repo.dirstate.savebackup(repo.currenttransaction(), self._backupname)
        narrowspec.savewcbackup(repo, self._narrowspecbackupname)
        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: %s")
                   % self._backupname)
            raise error.Abort(msg)

        self._repo.dirstate.clearbackup(self._repo.currenttransaction(),
                                         self._backupname)
        narrowspec.clearwcbackup(self._repo, self._narrowspecbackupname)
        self._active = False
        self._closed = True

    def _abort(self):
        narrowspec.restorewcbackup(self._repo, self._narrowspecbackupname)
        self._repo.dirstate.restorebackup(self._repo.currenttransaction(),
                                           self._backupname)
        self._active = False

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