1#!/usr/bin/env python3
2#
3# Copyright (c) 2015-2017 The Khronos Group Inc.
4# Copyright (c) 2015-2017 Valve Corporation
5# Copyright (c) 2015-2017 LunarG, Inc.
6# Copyright (c) 2015-2017 Google Inc.
7#
8# Licensed under the Apache License, Version 2.0 (the "License");
9# you may not use this file except in compliance with the License.
10# You may obtain a copy of the License at
11#
12#     http://www.apache.org/licenses/LICENSE-2.0
13#
14# Unless required by applicable law or agreed to in writing, software
15# distributed under the License is distributed on an "AS IS" BASIS,
16# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17# See the License for the specific language governing permissions and
18# limitations under the License.
19#
20# Author: Cort Stratton <cort@google.com>
21# Author: Jean-Francois Roy <jfroy@google.com>
22
23import argparse
24import hashlib
25import subprocess
26
27def generate(symbol_name, commit_id, output_header_file):
28    # Write commit ID to output header file
29    with open(output_header_file, "w") as header_file:
30         # File Comment
31        file_comment = '// *** THIS FILE IS GENERATED - DO NOT EDIT ***\n'
32        file_comment += '// See external_revision_generator.py for modifications\n'
33        header_file.write(file_comment)
34        # Copyright Notice
35        copyright = ''
36        copyright += '\n'
37        copyright += '/***************************************************************************\n'
38        copyright += ' *\n'
39        copyright += ' * Copyright (c) 2015-2017 The Khronos Group Inc.\n'
40        copyright += ' * Copyright (c) 2015-2017 Valve Corporation\n'
41        copyright += ' * Copyright (c) 2015-2017 LunarG, Inc.\n'
42        copyright += ' * Copyright (c) 2015-2017 Google Inc.\n'
43        copyright += ' *\n'
44        copyright += ' * Licensed under the Apache License, Version 2.0 (the "License");\n'
45        copyright += ' * you may not use this file except in compliance with the License.\n'
46        copyright += ' * You may obtain a copy of the License at\n'
47        copyright += ' *\n'
48        copyright += ' *     http://www.apache.org/licenses/LICENSE-2.0\n'
49        copyright += ' *\n'
50        copyright += ' * Unless required by applicable law or agreed to in writing, software\n'
51        copyright += ' * distributed under the License is distributed on an "AS IS" BASIS,\n'
52        copyright += ' * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n'
53        copyright += ' * See the License for the specific language governing permissions and\n'
54        copyright += ' * limitations under the License.\n'
55        copyright += ' *\n'
56        copyright += ' * Author: Chris Forbes <chrisforbes@google.com>\n'
57        copyright += ' * Author: Cort Stratton <cort@google.com>\n'
58        copyright += ' *\n'
59        copyright += ' ****************************************************************************/\n'
60        header_file.write(copyright)
61        # Contents
62        contents = '#pragma once\n\n'
63        contents += '#define %s "%s"\n' % (symbol_name, commit_id)
64        header_file.write(contents)
65
66def get_commit_id_from_git(git_binary, source_dir):
67    return subprocess.check_output([git_binary, "rev-parse", "HEAD"], cwd=source_dir).decode('utf-8').strip()
68
69def is_sha1(str):
70    try: str_as_int = int(str, 16)
71    except ValueError: return False
72    return len(str) == 40
73
74def get_commit_id_from_file(rev_file):
75    with open(rev_file, 'r') as rev_stream:
76        rev_contents = rev_stream.read()
77        rev_contents_stripped = rev_contents.strip()
78        if is_sha1(rev_contents_stripped):
79            return rev_contents_stripped;
80        # otherwise, SHA1 the entire (unstripped) file contents
81        sha1 = hashlib.sha1();
82        sha1.update(rev_contents.encode('utf-8'))
83        return sha1.hexdigest()
84
85def main():
86    parser = argparse.ArgumentParser()
87    parser.add_argument("-s", "--symbol_name", metavar="SYMBOL_NAME", required=True, help="C symbol name")
88    parser.add_argument("-o", "--output_header_file", metavar="OUTPUT_HEADER_FILE", required=True, help="output header file path")
89    rev_method_group = parser.add_mutually_exclusive_group(required=True)
90    rev_method_group.add_argument("--git_dir", metavar="SOURCE_DIR", help="git working copy directory")
91    rev_method_group.add_argument("--rev_file", metavar="REVISION_FILE", help="source revision file path (must contain a SHA1 hash")
92    args = parser.parse_args()
93
94    # We can either parse the latest Git commit ID out of the specified repository (preferred where possible),
95    # or computing the SHA1 hash of the contents of a file passed on the command line and (where necessary --
96    # e.g. when building the layers outside of a Git environment).
97    if args.git_dir is not None:
98        # Extract commit ID from the specified source directory
99        try:
100            commit_id = get_commit_id_from_git('git', args.git_dir)
101        except WindowsError:
102            # Call git.bat on Windows for compatiblity.
103            commit_id = get_commit_id_from_git('git.bat', args.git_dir)
104    elif args.rev_file is not None:
105        # Read the commit ID from a file.
106        commit_id = get_commit_id_from_file(args.rev_file)
107
108    if not is_sha1(commit_id):
109        raise ValueError("commit ID for " + args.symbol_name + " must be a SHA1 hash.")
110
111    generate(args.symbol_name, commit_id, args.output_header_file)
112
113if __name__ == '__main__':
114    main()
115