Home | History | Annotate | Download | only in lshal 
      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 <condition_variable>
     18 #include <chrono>
     19 #include <functional>
     20 #include <mutex>
     21 #include <thread>
     22 
     23 #include <hidl/Status.h>
     24 
     25 namespace android {
     26 namespace lshal {
     27 
     28 static constexpr std::chrono::milliseconds IPC_CALL_WAIT{500};
     29 
     30 class BackgroundTaskState {
     31 public:
     32     BackgroundTaskState(std::function<void(void)> &&func)
     33             : mFunc(std::forward<decltype(func)>(func)) {}
     34     void notify() {
     35         std::unique_lock<std::mutex> lock(mMutex);
     36         mFinished = true;
     37         lock.unlock();
     38         mCondVar.notify_all();
     39     }
     40     template<class C, class D>
     41     bool wait(std::chrono::time_point<C, D> end) {
     42         std::unique_lock<std::mutex> lock(mMutex);
     43         mCondVar.wait_until(lock, end, [this](){ return this->mFinished; });
     44         return mFinished;
     45     }
     46     void operator()() {
     47         mFunc();
     48     }
     49 private:
     50     std::mutex mMutex;
     51     std::condition_variable mCondVar;
     52     bool mFinished = false;
     53     std::function<void(void)> mFunc;
     54 };
     55 
     56 void *callAndNotify(void *data) {
     57     BackgroundTaskState &state = *static_cast<BackgroundTaskState *>(data);
     58     state();
     59     state.notify();
     60     return NULL;
     61 }
     62 
     63 template<class R, class P>
     64 bool timeout(std::chrono::duration<R, P> delay, std::function<void(void)> &&func) {
     65     auto now = std::chrono::system_clock::now();
     66     BackgroundTaskState state{std::forward<decltype(func)>(func)};
     67     pthread_t thread;
     68     if (pthread_create(&thread, NULL, callAndNotify, &state)) {
     69         std::cerr << "FATAL: could not create background thread." << std::endl;
     70         return false;
     71     }
     72     bool success = state.wait(now + delay);
     73     if (!success) {
     74         pthread_kill(thread, SIGINT);
     75     }
     76     pthread_join(thread, NULL);
     77     return success;
     78 }
     79 
     80 template<class R, class P, class Function, class I, class... Args>
     81 typename std::result_of<Function(I *, Args...)>::type
     82 timeoutIPC(std::chrono::duration<R, P> wait, const sp<I> &interfaceObject, Function &&func,
     83            Args &&... args) {
     84     using ::android::hardware::Status;
     85     typename std::result_of<Function(I *, Args...)>::type ret{Status::ok()};
     86     auto boundFunc = std::bind(std::forward<Function>(func),
     87             interfaceObject.get(), std::forward<Args>(args)...);
     88     bool success = timeout(wait, [&ret, &boundFunc] {
     89         ret = std::move(boundFunc());
     90     });
     91     if (!success) {
     92         return Status::fromStatusT(TIMED_OUT);
     93     }
     94     return ret;
     95 }
     96 
     97 template<class Function, class I, class... Args>
     98 typename std::result_of<Function(I *, Args...)>::type
     99 timeoutIPC(const sp<I> &interfaceObject, Function &&func, Args &&... args) {
    100     return timeoutIPC(IPC_CALL_WAIT, interfaceObject, func, args...);
    101 }
    102 
    103 
    104 }  // namespace lshal
    105 }  // namespace android
    106