3524 class dirstateguard(object):

  3525 dirstateguard = dirstateguardmod.dirstateguard

  3525     '''Restore dirstate at unexpected failure.

  3526 

  3527     At the construction, this class does:

  3528 

  3529     - write current ``repo.dirstate`` out, and

  3530     - save ``.hg/dirstate`` into the backup file

  3531 

  3532     This restores ``.hg/dirstate`` from backup file, if ``release()``

  3533     is invoked before ``close()``.

  3534 

  3535     This just removes the backup file at ``close()`` before ``release()``.

  3536     '''

  3537 

  3538     def __init__(self, repo, name):

  3539         self._repo = repo

  3540         self._active = False

  3541         self._closed = False

  3542         self._suffix = '.backup.%s.%d' % (name, id(self))

  3543         repo.dirstate.savebackup(repo.currenttransaction(), self._suffix)

  3544         self._active = True

  3545 

  3546     def __del__(self):

  3547         if self._active: # still active

  3548             # this may occur, even if this class is used correctly:

  3549             # for example, releasing other resources like transaction

  3550             # may raise exception before ``dirstateguard.release`` in

  3551             # ``release(tr, ....)``.

  3552             self._abort()

  3553 

  3554     def close(self):

  3555         if not self._active: # already inactivated

  3556             msg = (_("can't close already inactivated backup: dirstate%s")

  3557                    % self._suffix)

  3558             raise error.Abort(msg)

  3559 

  3560         self._repo.dirstate.clearbackup(self._repo.currenttransaction(),

  3561                                          self._suffix)

  3562         self._active = False

  3563         self._closed = True

  3564 

  3565     def _abort(self):

  3566         self._repo.dirstate.restorebackup(self._repo.currenttransaction(),

  3567                                            self._suffix)

  3568         self._active = False

  3569 

  3570     def release(self):

  3571         if not self._closed:

  3572             if not self._active: # already inactivated

  3573                 msg = (_("can't release already inactivated backup:"

  3574                          " dirstate%s")

  3575                        % self._suffix)

  3576                 raise error.Abort(msg)

  3577             self._abort()