1#
2# diffoscope: in-depth comparison of files, archives, and directories
3#
4# Copyright © 2015 Jérémy Bobbio <lunar@debian.org>
5# Copyright © 2015-2020 Chris Lamb <lamby@debian.org>
6#
7# diffoscope is free software: you can redistribute it and/or modify
8# it under the terms of the GNU General Public License as published by
9# the Free Software Foundation, either version 3 of the License, or
10# (at your option) any later version.
11#
12# diffoscope is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15# GNU General Public License for more details.
16#
17# You should have received a copy of the GNU General Public License
18# along with diffoscope.  If not, see <https://www.gnu.org/licenses/>.
19
20import os
21import stat
22import logging
23
24from diffoscope.tempfiles import get_named_temporary_file
25from diffoscope.difference import Difference
26
27from .binary import FilesystemFile
28from .utils.file import File
29
30logger = logging.getLogger(__name__)
31
32
33class Device(File):
34    DESCRIPTION = "character/block devices"
35
36    @classmethod
37    def recognizes(cls, file):
38        return file.is_device()
39
40    def get_device(self):
41        assert isinstance(self, FilesystemFile)
42        st = os.lstat(self.name)
43        return st.st_mode, os.major(st.st_rdev), os.minor(st.st_rdev)
44
45    def has_same_content_as(self, other):
46        try:
47            return self.get_device() == other.get_device()
48        except (AttributeError, OSError):
49            # 'other' is not a device, or something.
50            logger.debug("has_same_content: Not a device: %s", other)
51            return False
52
53    def create_placeholder(self):
54        with get_named_temporary_file(mode="w+", delete=False) as f:
55            f.write(format_device(*self.get_device()))
56            f.flush()
57            return f.name
58
59    @property
60    def path(self):
61        if not hasattr(self, "_placeholder"):
62            self._placeholder = self.create_placeholder()
63        return self._placeholder
64
65    def cleanup(self):
66        if hasattr(self, "_placeholder"):
67            os.remove(self._placeholder)
68            del self._placeholder
69        super().cleanup()
70
71    def compare(self, other, source=None):
72        with open(self.path) as my_content, open(other.path) as other_content:
73            return Difference.from_text_readers(
74                my_content,
75                other_content,
76                self.name,
77                other.name,
78                source=source,
79                comment="device",
80            )
81
82
83def format_device(mode, major, minor):
84    if stat.S_ISCHR(mode):
85        kind = "character"
86    elif stat.S_ISBLK(mode):
87        kind = "block"
88    else:
89        kind = "weird"
90    return f"device:{kind}\nmajor: {major}\nminor: {minor}\n"
91