HidlTransportUtils.h revision a7b2bb72eb9ed9345307c80ecc3386338ecddb9f 
1/*
2 * Copyright (C) 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
17#ifndef ANDROID_HIDL_TRANSPORT_UTILS_H
18#define ANDROID_HIDL_TRANSPORT_UTILS_H
19
20#include <android/hidl/base/1.0/IBase.h>
21
22namespace android {
23namespace hardware {
24namespace details {
25
26/*
27 * Verifies the interface chain of 'interface' contains 'castTo'
28 * @param emitError if emitError is false, return Return<bool>{false} on error; if emitError
29 * is true, the Return<bool> object contains the actual error.
30 */
31inline Return<bool> canCastInterface(::android::hidl::base::V1_0::IBase* interface,
32        const char* castTo, bool emitError = false) {
33    if (interface == nullptr) {
34        return false;
35    }
36
37    bool canCast = false;
38    auto chainRet = interface->interfaceChain([&](const hidl_vec<hidl_string> &types) {
39        for (size_t i = 0; i < types.size(); i++) {
40            if (types[i] == castTo) {
41                canCast = true;
42                break;
43            }
44        }
45    });
46
47    if (!chainRet.isOk()) {
48        // call fails, propagate the error if emitError
49        return emitError
50                ? details::StatusOf<void, bool>(chainRet)
51                : Return<bool>(false);
52    }
53
54    return canCast;
55}
56
57inline std::string getDescriptor(::android::hidl::base::V1_0::IBase* interface) {
58    std::string myDescriptor{};
59    auto ret = interface->interfaceDescriptor([&](const hidl_string &types) {
60        myDescriptor = types.c_str();
61    });
62    ret.isOk(); // ignored, return empty string if not isOk()
63    return myDescriptor;
64}
65
66}   // namespace details
67}   // namespace hardware
68}   // namespace android
69
70#endif //ANDROID_HIDL_TRANSPORT_UTILS_H
71