1 /* 2 * Copyright (C) 2020 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 MINIFENCE_H 18 #define MINIFENCE_H 19 20 #include <utils/RefBase.h> 21 22 namespace android { 23 24 /* MiniFence is a minimal re-implementation of Fence from libui. It exists to 25 * avoid linking the HWC2on1Adapter to libui and satisfy Treble requirements. 26 */ 27 class MiniFence : public LightRefBase<MiniFence> { 28 public: 29 static const sp<MiniFence> NO_FENCE; 30 31 // Construct a new MiniFence object with an invalid file descriptor. 32 MiniFence(); 33 34 // Construct a new MiniFence object to manage a given fence file descriptor. 35 // When the new MiniFence object is destructed the file descriptor will be 36 // closed. 37 explicit MiniFence(int fenceFd); 38 39 // Not copyable or movable. 40 MiniFence(const MiniFence& rhs) = delete; 41 MiniFence& operator=(const MiniFence& rhs) = delete; 42 MiniFence(MiniFence&& rhs) = delete; 43 MiniFence& operator=(MiniFence&& rhs) = delete; 44 45 // Return a duplicate of the fence file descriptor. The caller is 46 // responsible for closing the returned file descriptor. On error, -1 will 47 // be returned and errno will indicate the problem. 48 int dup() const; 49 50 private: 51 // Only allow instantiation using ref counting. 52 friend class LightRefBase<MiniFence>; 53 ~MiniFence(); 54 55 int mFenceFd; 56 57 }; 58 } 59 #endif //MINIFENCE_H 60