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1# -*- coding:utf-8 -*-
2# Copyright 2016 The Android Open Source Project
3#
4# Licensed under the Apache License, Version 2.0 (the "License");
5# you may not use this file except in compliance with the License.
6# You may obtain a copy of the License at
7#
8#      http://www.apache.org/licenses/LICENSE-2.0
9#
10# Unless required by applicable law or agreed to in writing, software
11# distributed under the License is distributed on an "AS IS" BASIS,
12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15
16"""Git helper functions."""
17
18from __future__ import print_function
19
20import os
21import re
22import sys
23
24_path = os.path.realpath(__file__ + '/../..')
25if sys.path[0] != _path:
26    sys.path.insert(0, _path)
27del _path
28
29import rh.utils
30
31
32def get_upstream_remote():
33    """Returns the current upstream remote name."""
34    # First get the current branch name.
35    cmd = ['git', 'rev-parse', '--abbrev-ref', 'HEAD']
36    result = rh.utils.run_command(cmd, capture_output=True)
37    branch = result.output.strip()
38
39    # Then get the remote associated with this branch.
40    cmd = ['git', 'config', 'branch.%s.remote' % branch]
41    result = rh.utils.run_command(cmd, capture_output=True)
42    return result.output.strip()
43
44
45def get_upstream_branch():
46    """Returns the upstream tracking branch of the current branch.
47
48    Raises:
49      Error if there is no tracking branch
50    """
51    cmd = ['git', 'symbolic-ref', 'HEAD']
52    result = rh.utils.run_command(cmd, capture_output=True)
53    current_branch = result.output.strip().replace('refs/heads/', '')
54    if not current_branch:
55        raise ValueError('Need to be on a tracking branch')
56
57    cfg_option = 'branch.' + current_branch + '.%s'
58    cmd = ['git', 'config', cfg_option % 'merge']
59    result = rh.utils.run_command(cmd, capture_output=True)
60    full_upstream = result.output.strip()
61    # If remote is not fully qualified, add an implicit namespace.
62    if '/' not in full_upstream:
63        full_upstream = 'refs/heads/%s' % full_upstream
64    cmd = ['git', 'config', cfg_option % 'remote']
65    result = rh.utils.run_command(cmd, capture_output=True)
66    remote = result.output.strip()
67    if not remote or not full_upstream:
68        raise ValueError('Need to be on a tracking branch')
69
70    return full_upstream.replace('heads', 'remotes/' + remote)
71
72
73def get_commit_for_ref(ref):
74    """Returns the latest commit for this ref."""
75    cmd = ['git', 'rev-parse', ref]
76    result = rh.utils.run_command(cmd, capture_output=True)
77    return result.output.strip()
78
79
80def get_remote_revision(ref, remote):
81    """Returns the remote revision for this ref."""
82    prefix = 'refs/remotes/%s/' % remote
83    if ref.startswith(prefix):
84        return ref[len(prefix):]
85    return ref
86
87
88def get_patch(commit):
89    """Returns the patch for this commit."""
90    cmd = ['git', 'format-patch', '--stdout', '-1', commit]
91    return rh.utils.run_command(cmd, capture_output=True).output
92
93
94def _try_utf8_decode(data):
95    """Attempts to decode a string as UTF-8.
96
97    Returns:
98      The decoded Unicode object, or the original string if parsing fails.
99    """
100    try:
101        return unicode(data, 'utf-8', 'strict')
102    except UnicodeDecodeError:
103        return data
104
105
106def get_file_content(commit, path):
107    """Returns the content of a file at a specific commit.
108
109    We can't rely on the file as it exists in the filesystem as people might be
110    uploading a series of changes which modifies the file multiple times.
111
112    Note: The "content" of a symlink is just the target.  So if you're expecting
113    a full file, you should check that first.  One way to detect is that the
114    content will not have any newlines.
115    """
116    cmd = ['git', 'show', '%s:%s' % (commit, path)]
117    return rh.utils.run_command(cmd, capture_output=True).output
118
119
120# RawDiffEntry represents a line of raw formatted git diff output.
121RawDiffEntry = rh.utils.collection(
122    'RawDiffEntry',
123    src_mode=0, dst_mode=0, src_sha=None, dst_sha=None,
124    status=None, score=None, src_file=None, dst_file=None, file=None)
125
126
127# This regular expression pulls apart a line of raw formatted git diff output.
128DIFF_RE = re.compile(
129    r':(?P<src_mode>[0-7]*) (?P<dst_mode>[0-7]*) '
130    r'(?P<src_sha>[0-9a-f]*)(\.)* (?P<dst_sha>[0-9a-f]*)(\.)* '
131    r'(?P<status>[ACDMRTUX])(?P<score>[0-9]+)?\t'
132    r'(?P<src_file>[^\t]+)\t?(?P<dst_file>[^\t]+)?')
133
134
135def raw_diff(path, target):
136    """Return the parsed raw format diff of target
137
138    Args:
139      path: Path to the git repository to diff in.
140      target: The target to diff.
141
142    Returns:
143      A list of RawDiffEntry's.
144    """
145    entries = []
146
147    cmd = ['git', 'diff', '-M', '--raw', target]
148    diff = rh.utils.run_command(cmd, cwd=path, capture_output=True).output
149    diff_lines = diff.strip().splitlines()
150    for line in diff_lines:
151        match = DIFF_RE.match(line)
152        if not match:
153            raise ValueError('Failed to parse diff output: %s' % line)
154        diff = RawDiffEntry(**match.groupdict())
155        diff.src_mode = int(diff.src_mode)
156        diff.dst_mode = int(diff.dst_mode)
157        diff.file = diff.dst_file if diff.dst_file else diff.src_file
158        entries.append(diff)
159
160    return entries
161
162
163def get_affected_files(commit):
164    """Returns list of file paths that were modified/added.
165
166    Returns:
167      A list of modified/added (and perhaps deleted) files
168    """
169    return raw_diff(os.getcwd(), '%s^!' % commit)
170
171
172def get_commits(ignore_merged_commits=False):
173    """Returns a list of commits for this review."""
174    cmd = ['git', 'log', '%s..' % get_upstream_branch(), '--format=%H']
175    if ignore_merged_commits:
176        cmd.append('--first-parent')
177    return rh.utils.run_command(cmd, capture_output=True).output.split()
178
179
180def get_commit_desc(commit):
181    """Returns the full commit message of a commit."""
182    cmd = ['git', 'log', '--format=%B', commit + '^!']
183    return rh.utils.run_command(cmd, capture_output=True).output
184
185
186def find_repo_root(path=None):
187    """Locate the top level of this repo checkout starting at |path|."""
188    if path is None:
189        path = os.getcwd()
190    orig_path = path
191
192    path = os.path.abspath(path)
193    while not os.path.exists(os.path.join(path, '.repo')):
194        path = os.path.dirname(path)
195        if path == '/':
196            raise ValueError('Could not locate .repo in %s' % orig_path)
197
198    return path
199