1# Copyright (C) 2006 Canonical Ltd
2#
3# This program is free software; you can redistribute it and/or modify
4# it under the terms of the GNU General Public License as published by
5# the Free Software Foundation; either version 2 of the License, or
6# (at your option) any later version.
7#
8# This program is distributed in the hope that it will be useful,
9# but WITHOUT ANY WARRANTY; without even the implied warranty of
10# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11# GNU General Public License for more details.
12#
13# You should have received a copy of the GNU General Public License
14# along with this program; if not, write to the Free Software
15# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
16
17"""Fake transport with some restrictions of Windows VFAT filesystems.
18
19VFAT on Windows has several restrictions that are not present on unix
20filesystems, which are imposed by this transport.
21
22VFAT is strictly 8-bit using codepages to represent non-ascii characters.
23This implementation currently doesn't model the codepage but just insists
24on only ascii characters being written.
25
26Restrictions imposed by this transport:
27
28 * filenames are squashed to lowercase
29 * filenames containing non-ascii characters are not allowed
30 * filenames containing the characters "@<>" are not allowed
31   (there should be more?)
32
33Some other restrictions are not implemented yet, but possibly could be:
34
35 * open files can't be deleted or renamed
36 * directories containing open files can't be renamed
37 * special device names (NUL, LPT, ...) are not allowed
38
39"""
40
41import re
42
43from . import decorator
44
45
46# TODO: It might be nice if these hooks were available in a more general way
47# on all paths passed in to the Transport, so that we didn't have to hook
48# every single method.
49
50# TODO: Perhaps don't inherit from TransportDecorator so that methods
51# which are not implemented here fail by default?
52
53
54class FakeVFATTransportDecorator(decorator.TransportDecorator):
55    """A decorator that can convert any transport to be readonly.
56
57    This is requested via the 'vfat+' prefix to get_transport().
58
59    This is intended only for use in testing and doesn't implement every
60    method very well yet.
61
62    This transport is typically layered on a local or memory transport
63    which actually stored the files.
64    """
65
66    def _can_roundtrip_unix_modebits(self):
67        """See Transport._can_roundtrip_unix_modebits()."""
68        return False
69
70    @classmethod
71    def _get_url_prefix(self):
72        """Readonly transport decorators are invoked via 'vfat+'"""
73        return 'vfat+'
74
75    def _squash_name(self, name):
76        """Return vfat-squashed filename.
77
78        The name is returned as it will be stored on disk.  This raises an
79        error if there are invalid characters in the name.
80        """
81        if re.search(r'[?*:;<>]', name):
82            raise ValueError("illegal characters for VFAT filename: %r" % name)
83        return name.lower()
84
85    def get(self, relpath):
86        return self._decorated.get(self._squash_name(relpath))
87
88    def mkdir(self, relpath, mode=None):
89        return self._decorated.mkdir(self._squash_name(relpath), 0o755)
90
91    def has(self, relpath):
92        return self._decorated.has(self._squash_name(relpath))
93
94    def _readv(self, relpath, offsets):
95        return self._decorated.readv(self._squash_name(relpath), offsets)
96
97    def put_file(self, relpath, f, mode=None):
98        return self._decorated.put_file(self._squash_name(relpath), f, mode)
99
100
101def get_test_permutations():
102    """Return the permutations to be used in testing."""
103    from breezy.tests import test_server
104    return [(FakeVFATTransportDecorator, test_server.FakeVFATServer), ]
105