1
# Copyright (C) 2004, 2005 by Canonical Ltd
1
# Copyright (C) 2004, 2005 Canonical Ltd
3
3
# This program is free software; you can redistribute it and/or modify
4
4
# it under the terms of the GNU General Public License as published by
5
5
# the Free Software Foundation; either version 2 of the License, or
6
6
# (at your option) any later version.
8
8
# This program is distributed in the hope that it will be useful,
9
9
# but WITHOUT ANY WARRANTY; without even the implied warranty of
10
10
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11
11
# GNU General Public License for more details.
13
13
# You should have received a copy of the GNU General Public License
14
14
# along with this program; if not, write to the Free Software
15
15
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19
from warnings import warn
20
from bzrlib.osutils import rename
21
from bzrlib.lazy_import import lazy_import
22
lazy_import(globals(), """
34
# not forksafe - but we dont fork.
23
39
class AtomicFile(object):
24
40
"""A file that does an atomic-rename to move into place.
28
44
Open this as for a regular file, then use commit() to move into
29
45
place or abort() to cancel.
31
An encoding can be specified; otherwise the default is ascii.
34
def __init__(self, filename, mode='wb', encoding=None, new_mode=None):
35
if mode != 'wb' and mode != 'wt':
48
__slots__ = ['tmpfilename', 'realfilename', '_fd']
50
def __init__(self, filename, mode='wb', new_mode=None):
56
_hostname = socket.gethostname()
58
self.tmpfilename = '%s.%d.%s.tmp' % (filename, _pid, _hostname)
60
self.realfilename = filename
62
flags = os.O_EXCL | os.O_CREAT | os.O_WRONLY
64
flags |= osutils.O_BINARY
36
66
raise ValueError("invalid AtomicFile mode %r" % mode)
39
self.tmpfilename = '%s.%d.%s.tmp' % (filename, os.getpid(),
41
self.realfilename = filename
68
if new_mode is not None:
45
self.f = codecs.open(self.tmpfilename, mode, encoding)
47
self.f = open(self.tmpfilename, mode)
49
self.write = self.f.write
51
self._new_mode = new_mode
73
# Use a low level fd operation to avoid chmodding later.
74
# This may not succeed, but it should help most of the time
75
self._fd = os.open(self.tmpfilename, flags, local_mode)
77
if new_mode is not None:
78
# Because of umask issues, we may need to chmod anyway
79
# the common case is that we won't, though.
80
st = os.fstat(self._fd)
81
if stat.S_IMODE(st.st_mode) != new_mode:
82
os.chmod(self.tmpfilename, new_mode)
84
def _get_closed(self):
85
symbol_versioning.warn('AtomicFile.closed deprecated in bzr 0.10',
86
DeprecationWarning, stacklevel=2)
87
return self._fd is None
89
closed = property(_get_closed)
54
91
def __repr__(self):
55
92
return '%s(%r)' % (self.__class__.__name__,
95
def write(self, data):
96
"""Write some data to the file. Like file.write()"""
97
os.write(self._fd, data)
99
def _close_tmpfile(self, func_name):
100
"""Close the local temp file in preparation for commit or abort"""
102
raise errors.AtomicFileAlreadyClosed(path=self.realfilename,
60
109
"""Close the file and move to final name."""
64
raise Exception('%r is already closed' % self)
71
if self._new_mode is None:
72
self._new_mode = os.lstat(self.realfilename).st_mode
74
if e.errno != errno.ENOENT:
77
os.chmod(self.tmpfilename, self._new_mode)
79
rename(self.tmpfilename, self.realfilename)
110
self._close_tmpfile('commit')
111
osutils.rename(self.tmpfilename, self.realfilename)
83
114
"""Discard temporary file without committing changes."""
87
raise Exception('%r is already closed' % self)
115
self._close_tmpfile('abort')
92
116
os.remove(self.tmpfilename)
96
119
"""Discard the file unless already committed."""
120
if self._fd is not None:
101
123
def __del__(self):
102
if hasattr(self, 'closed') and not self.closed:
103
warn("%r leaked" % self)
124
if self._fd is not None:
125
warnings.warn("%r leaked" % self)