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_HIDL_HAL_DEATH_HANDLER_H
18 #define ANDROID_HARDWARE_HIDL_HAL_DEATH_HANDLER_H
19 
20 #include <functional>
21 #include <mutex>
22 #include <unordered_map>
23 
24 #include <hidl/HidlSupport.h>
25 #include <utils/Singleton.h>
26 
27 using android::hardware::hidl_death_recipient;
28 using android::hidl::base::V1_0::IBase;
29 
30 namespace android {
31 
32 class HalDeathHandler : public hidl_death_recipient, private Singleton<HalDeathHandler> {
33   public:
34     typedef std::function<void()> AtExitHandler;
35 
36     // Note that the exit handler gets called using a thread from
37     // RPC threadpool, thus it needs to be thread-safe.
38     void registerAtExitHandler(void* cookie, AtExitHandler handler);
39     void unregisterAtExitHandler(void* cookie);
40 
41     // hidl_death_recipient
42     virtual void serviceDied(uint64_t cookie, const wp<IBase>& who);
43 
44     // Used both for (un)registering handlers, and for passing to
45     // '(un)linkToDeath'.
46     static sp<HalDeathHandler> getInstance();
47 
48   private:
49     friend class Singleton<HalDeathHandler>;
50     typedef std::unordered_map<void*, AtExitHandler> Handlers;
51 
52     HalDeathHandler();
53     virtual ~HalDeathHandler();
54 
55     sp<HalDeathHandler> mSelf;  // Allows the singleton instance to live forever.
56     std::mutex mHandlersLock;
57     Handlers mHandlers;
58 };
59 
60 }  // namespace android
61 
62 #endif // ANDROID_HARDWARE_HIDL_HAL_DEATH_HANDLER_H
63