1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
#!/usr/bin/python
# Copyright (C) 2018 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Generates wrapped include files to workaround -Wunused-parameter errors.
In Chrome repository, "-Wunused-parameter" is disabled, and several header
files in Chrome repository have actually unused-parameter.
One of the typical scenarios is; in Chrome, Observer class is often defined
as follows:
class Foo {
public:
class Observer {
public:
virtual void OnSomeEvent(EventArg arg) {}
virtual void OnAnotherEvent(EventArg arg) {}
...
};
...
};
Here, On...Event() methods do nothing by default, and subclasses will override
only necessary ones.
In this use case, argument names can also work as documentation, and overrides
can use these good interface-defined default names as a starting point for
their implementation.
On the other hand, in Android, -Wunused-parameter is enabled by default.
Thus, if such a project includes header files from libchrome, it could cause
a compile error (by the warning and "-Werror").
To avoid such a situation, libchrome exports include files wrapped by the
pragmas as follows.
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
${actual_include_file_content}
#pragma GCC diagnostic pop
so, the unused-parameter warning generated by the libchrome include headers
will be ignored.
Note that these GCC pragmas are also supported by clang for compatibility. cf)
https://clang.llvm.org/docs/UsersManual.html#controlling-diagnostics-via-pragmas
Usage: include_generator.py $(in) $(out)
"""
import sys
def _generate(input_path, output_path):
"""Generates a include file wrapped by pragmas.
Reads the file at |input_path| and output the content with wrapping by
#pragma to ignore unused-parameter warning into the file at |output_path|.
If the parent directories of |output_path| do not exist, creates them.
Args:
input_path: Path to the source file. Expected this is a chrome's header
file.
output_path: Path to the output file.
"""
with open(input_path, 'r') as f:
content = f.read()
with open(output_path, 'w') as f:
f.writelines([
'// Generated by %s\n' % sys.argv[0],
'#pragma GCC diagnostic push\n'
'#pragma GCC diagnostic ignored "-Wunused-parameter"\n',
content,
'#pragma GCC diagnostic pop\n'])
def main():
_generate(*sys.argv[1:])
if __name__ == '__main__':
main()
|
