1# reflog.py -- Parsing and writing reflog files
2# Copyright (C) 2015 Jelmer Vernooij and others.
3#
4# Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU
5# General Public License as public by the Free Software Foundation; version 2.0
6# or (at your option) any later version. You can redistribute it and/or
7# modify it under the terms of either of these two licenses.
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14#
15# You should have received a copy of the licenses; if not, see
16# <http://www.gnu.org/licenses/> for a copy of the GNU General Public License
17# and <http://www.apache.org/licenses/LICENSE-2.0> for a copy of the Apache
18# License, Version 2.0.
19#
20
21"""Utilities for reading and generating reflogs.
22"""
23
24import collections
25
26from dulwich.objects import (
27    format_timezone,
28    parse_timezone,
29    ZERO_SHA,
30    )
31
32Entry = collections.namedtuple(
33    'Entry', ['old_sha', 'new_sha', 'committer', 'timestamp', 'timezone',
34              'message'])
35
36
37def format_reflog_line(old_sha, new_sha, committer, timestamp, timezone,
38                       message):
39    """Generate a single reflog line.
40
41    :param old_sha: Old Commit SHA
42    :param new_sha: New Commit SHA
43    :param committer: Committer name and e-mail
44    :param timestamp: Timestamp
45    :param timezone: Timezone
46    :param message: Message
47    """
48    if old_sha is None:
49        old_sha = ZERO_SHA
50    return (old_sha + b' ' + new_sha + b' ' + committer + b' ' +
51            str(int(timestamp)).encode('ascii') + b' ' +
52            format_timezone(timezone) + b'\t' + message)
53
54
55def parse_reflog_line(line):
56    """Parse a reflog line.
57
58    :param line: Line to parse
59    :return: Tuple of (old_sha, new_sha, committer, timestamp, timezone,
60        message)
61    """
62    (begin, message) = line.split(b'\t', 1)
63    (old_sha, new_sha, rest) = begin.split(b' ', 2)
64    (committer, timestamp_str, timezone_str) = rest.rsplit(b' ', 2)
65    return Entry(old_sha, new_sha, committer, int(timestamp_str),
66                 parse_timezone(timezone_str)[0], message)
67
68
69def read_reflog(f):
70    """Read reflog.
71
72    :param f: File-like object
73    :returns: Iterator over Entry objects
74    """
75    for l in f:
76        yield parse_reflog_line(l)
77