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      1 /*
      2  * Copyright (C) 2013 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_HWUI_FUTURE_H
     18 #define ANDROID_HWUI_FUTURE_H
     19 
     20 #include <utils/RefBase.h>
     21 
     22 #include "Barrier.h"
     23 
     24 namespace android {
     25 namespace uirenderer {
     26 
     27 template <typename T>
     28 class Future : public LightRefBase<Future<T> > {
     29 public:
     30     explicit Future(Condition::WakeUpType type = Condition::WAKE_UP_ONE)
     31             : mBarrier(type), mResult() {}
     32     ~Future() {}
     33 
     34     /**
     35      * Returns the result of this future, blocking if
     36      * the result is not available yet.
     37      */
     38     T get() const {
     39         mBarrier.wait();
     40         return mResult;
     41     }
     42 
     43     /**
     44      * This method must be called only once.
     45      */
     46     void produce(T result) {
     47         mResult = result;
     48         mBarrier.open();
     49     }
     50 
     51 private:
     52     Barrier mBarrier;
     53     T mResult;
     54 };
     55 
     56 };  // namespace uirenderer
     57 };  // namespace android
     58 
     59 #endif  // ANDROID_HWUI_FUTURE_H
     60