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# Copyright (C) 2004, 2005 by Canonical Ltd
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# Copyright (C) 2005, 2006, 2008, 2009, 2010 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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from warnings import warn
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from osutils import rename
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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from __future__ import absolute_import
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from bzrlib.lazy_import import lazy_import
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lazy_import(globals(), """
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# not forksafe - but we dont fork.
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class AtomicFile(object):
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"""A file that does an atomic-rename to move into place.
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Open this as for a regular file, then use commit() to move into
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place or abort() to cancel.
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An encoding can be specified; otherwise the default is ascii.
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def __init__(self, filename, mode='wb', encoding=None):
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if mode != 'wb' and mode != 'wt':
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__slots__ = ['tmpfilename', 'realfilename', '_fd']
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def __init__(self, filename, mode='wb', new_mode=None):
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_hostname = osutils.get_host_name()
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self.tmpfilename = '%s.%d.%s.%s.tmp' % (filename, _pid, _hostname,
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osutils.rand_chars(10))
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self.realfilename = filename
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flags = os.O_EXCL | os.O_CREAT | os.O_WRONLY | osutils.O_NOINHERIT
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flags |= osutils.O_BINARY
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raise ValueError("invalid AtomicFile mode %r" % mode)
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self.tmpfilename = '%s.%d.%s.tmp' % (filename, os.getpid(),
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self.realfilename = filename
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self.f = codecs.open(self.tmpfilename, mode, encoding)
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if new_mode is not None:
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self.f = open(self.tmpfilename, mode)
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self.write = self.f.write
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# Use a low level fd operation to avoid chmodding later.
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# This may not succeed, but it should help most of the time
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self._fd = os.open(self.tmpfilename, flags, local_mode)
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if new_mode is not None:
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# Because of umask issues, we may need to chmod anyway
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# the common case is that we won't, though.
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st = os.fstat(self._fd)
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if stat.S_IMODE(st.st_mode) != new_mode:
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osutils.chmod_if_possible(self.tmpfilename, new_mode)
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def __repr__(self):
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return '%s(%r)' % (self.__class__.__name__,
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def write(self, data):
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"""Write some data to the file. Like file.write()"""
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os.write(self._fd, data)
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def _close_tmpfile(self, func_name):
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"""Close the local temp file in preparation for commit or abort"""
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raise errors.AtomicFileAlreadyClosed(path=self.realfilename,
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"""Close the file and move to final name."""
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raise Exception('%r is already closed' % self)
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rename(self.tmpfilename, self.realfilename)
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self._close_tmpfile('commit')
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osutils.rename(self.tmpfilename, self.realfilename)
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"""Discard temporary file without committing changes."""
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raise Exception('%r is already closed' % self)
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self._close_tmpfile('abort')
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os.remove(self.tmpfilename)
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"""Discard the file unless already committed."""
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if self._fd is not None:
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if hasattr(self, 'closed') and not self.closed:
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warn("%r leaked" % self)