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 #include <hidl/HidlTransportUtils.h>
18 
19 #include <android/hidl/base/1.0/IBase.h>
20 
21 namespace android {
22 namespace hardware {
23 namespace details {
24 
25 using ::android::hidl::base::V1_0::IBase;
26 
27 Return<bool> canCastInterface(IBase* interface, const char* castTo, bool emitError) {
28     if (interface == nullptr) {
29         return false;
30     }
31 
32     // b/68217907
33     // Every HIDL interface is a base interface.
34     if (std::string(IBase::descriptor) == castTo) {
35         return true;
36     }
37 
38     bool canCast = false;
39     auto chainRet = interface->interfaceChain([&](const hidl_vec<hidl_string> &types) {
40         for (size_t i = 0; i < types.size(); i++) {
41             if (types[i] == castTo) {
42                 canCast = true;
43                 break;
44             }
45         }
46     });
47 
48     if (!chainRet.isOk()) {
49         // call fails, propagate the error if emitError
50         return emitError
51                 ? details::StatusOf<void, bool>(chainRet)
52                 : Return<bool>(false);
53     }
54 
55     return canCast;
56 }
57 
58 std::string getDescriptor(IBase* interface) {
59     if (interface == nullptr) {
60         return "";
61     }
62 
63     std::string myDescriptor{};
64     auto ret = interface->interfaceDescriptor([&](const hidl_string &types) {
65         myDescriptor = types.c_str();
66     });
67     ret.isOk(); // ignored, return empty string if not isOk()
68     return myDescriptor;
69 }
70 
71 }  // namespace details
72 }  // namespace hardware
73 }  // namespace android
74