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We have at least three types with a close() and a release() method where the close() method is supposed to be called on success and the release() method is supposed to be called last, whether successful or not. Two of them (transaction and dirstateguard) already have identical implementations of __enter__ and __exit__. Let's extract a base class for this, so we reuse the code and so the third type (transactionmanager) can also be used as a context manager. Differential Revision: https://phab.mercurial-scm.org/D392
70 lines
2.2 KiB
Python
70 lines
2.2 KiB
Python
# dirstateguard.py - class to allow restoring dirstate after failure
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#
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# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>
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#
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# This software may be used and distributed according to the terms of the
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# GNU General Public License version 2 or any later version.
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from __future__ import absolute_import
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from .i18n import _
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from . import (
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error,
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util,
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)
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class dirstateguard(util.transactional):
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'''Restore dirstate at unexpected failure.
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At the construction, this class does:
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- write current ``repo.dirstate`` out, and
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- save ``.hg/dirstate`` into the backup file
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This restores ``.hg/dirstate`` from backup file, if ``release()``
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is invoked before ``close()``.
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This just removes the backup file at ``close()`` before ``release()``.
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'''
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def __init__(self, repo, name):
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self._repo = repo
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self._active = False
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self._closed = False
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self._backupname = 'dirstate.backup.%s.%d' % (name, id(self))
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repo.dirstate.savebackup(repo.currenttransaction(), self._backupname)
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self._active = True
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def __del__(self):
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if self._active: # still active
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# this may occur, even if this class is used correctly:
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# for example, releasing other resources like transaction
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# may raise exception before ``dirstateguard.release`` in
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# ``release(tr, ....)``.
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self._abort()
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def close(self):
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if not self._active: # already inactivated
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msg = (_("can't close already inactivated backup: %s")
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% self._backupname)
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raise error.Abort(msg)
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self._repo.dirstate.clearbackup(self._repo.currenttransaction(),
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self._backupname)
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self._active = False
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self._closed = True
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def _abort(self):
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self._repo.dirstate.restorebackup(self._repo.currenttransaction(),
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self._backupname)
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self._active = False
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def release(self):
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if not self._closed:
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if not self._active: # already inactivated
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msg = (_("can't release already inactivated backup: %s")
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% self._backupname)
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raise error.Abort(msg)
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self._abort()
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