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)
mBarrier(type)31             : mBarrier(type), mResult() {}
~Future()32     ~Future() {}
33 
34     /**
35      * Returns the result of this future, blocking if
36      * the result is not available yet.
37      */
get()38     T get() const {
39         mBarrier.wait();
40         return mResult;
41     }
42 
43     /**
44      * This method must be called only once.
45      */
produce(T result)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