1/*
2 * Copyright (C) 2017 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
17#ifndef ANDROID_HARDWARE_AUDIO_COMMON_TEST_UTILITY_RETURN_IN_H
18#define ANDROID_HARDWARE_AUDIO_COMMON_TEST_UTILITY_RETURN_IN_H
19
20#include <tuple>
21
22namespace android {
23namespace hardware {
24namespace audio {
25namespace common {
26namespace test {
27namespace utility {
28
29namespace detail {
30// Helper class to generate the HIDL synchronous callback
31template <class... ResultStore>
32class ReturnIn {
33   public:
34    // Provide to the constructor the variables where the output parameters must be copied
35    // TODO: take pointers to match google output parameter style ?
36    ReturnIn(ResultStore&... ts) : results(ts...) {}
37    // Synchronous callback
38    template <class... Results>
39    void operator()(Results&&... results) {
40        set(std::forward<Results>(results)...);
41    }
42
43   private:
44    // Recursively set all output parameters
45    template <class Head, class... Tail>
46    void set(Head&& head, Tail&&... tail) {
47        std::get<sizeof...(ResultStore) - sizeof...(Tail) - 1>(results) = std::forward<Head>(head);
48        set(std::forward<Tail>(tail)...);
49    }
50    // Trivial case
51    void set() {}
52
53    // All variables to set are stored here
54    std::tuple<ResultStore&...> results;
55};
56}  // namespace detail
57
58// Generate the HIDL synchronous callback with a copy policy
59// Input: the variables (lvalue references) where to copy the return values
60// Output: the callback to provide to a HIDL call with a synchronous callback
61// The output parameters *will be copied* do not use this function if you have
62// a zero copy policy
63template <class... ResultStore>
64detail::ReturnIn<ResultStore...> returnIn(ResultStore&... ts) {
65    return {ts...};
66}
67
68}  // namespace utility
69}  // namespace test
70}  // namespace common
71}  // namespace audio
72}  // namespace hardware
73}  // namespace android
74
75#endif  // ANDROID_HARDWARE_AUDIO_COMMON_TEST_UTILITY_RETURN_IN_H
76