1#!/usr/bin/env python3
2
3# Copyright 2021 gRPC authors.
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9#     http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16
17import sys
18
19
20# utility: print a big comment block into a set of files
21def put_banner(files, banner):
22    for f in files:
23        print('/*', file=f)
24        for line in banner:
25            print(' * %s' % line, file=f)
26        print(' */', file=f)
27        print('', file=f)
28
29
30with open('src/core/lib/promise/detail/switch.h', 'w') as H:
31    # copy-paste copyright notice from this file
32    with open(sys.argv[0]) as my_source:
33        copyright = []
34        for line in my_source:
35            if line[0] != '#':
36                break
37        for line in my_source:
38            if line[0] == '#':
39                copyright.append(line)
40                break
41        for line in my_source:
42            if line[0] != '#':
43                break
44            copyright.append(line)
45        put_banner([H], [line[2:].rstrip() for line in copyright])
46
47    put_banner([H], ["Automatically generated by %s" % sys.argv[0]])
48
49    print("#ifndef GRPC_CORE_LIB_PROMISE_DETAIL_SWITCH_H", file=H)
50    print("#define GRPC_CORE_LIB_PROMISE_DETAIL_SWITCH_H", file=H)
51    print('', file=H)
52    print('#include <grpc/support/port_platform.h>', file=H)
53    print('', file=H)
54    print("#include <stdlib.h>", file=H)
55    print('', file=H)
56    print("namespace grpc_core {", file=H)
57
58    for n in range(1, 33):
59        print('', file=H)
60        print("template <typename R, %s> R Switch(char idx, %s) {" % (
61            ", ".join("typename F%d" % i for i in range(0, n)),
62            ", ".join("F%d f%d" % (i, i) for i in range(0, n)),
63        ),
64              file=H)
65        print("  switch (idx) {", file=H)
66        for i in range(0, n):
67            print("   case %d: return f%d();" % (i, i), file=H)
68        print("  }", file=H)
69        print("  abort();", file=H)
70        print("}", file=H)
71
72    print('', file=H)
73    print("}", file=H)
74    print('', file=H)
75    print("#endif // GRPC_CORE_LIB_PROMISE_DETAIL_SWITCH_H", file=H)
76