1 /* 2 * Copyright (C) 2018 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_BUFFER_HUB_EVENT_FD_H_ 18 #define ANDROID_BUFFER_HUB_EVENT_FD_H_ 19 20 #include <android-base/unique_fd.h> 21 #include <utils/Errors.h> 22 23 namespace android { 24 25 class BufferHubEventFd { 26 public: 27 /** 28 * Constructs a valid event fd. 29 */ 30 BufferHubEventFd(); 31 32 /** 33 * Constructs from a valid event fd. Caller is responsible for the validity of the fd. Takes 34 * ownership. 35 */ 36 BufferHubEventFd(int fd); 37 38 /** 39 * Returns whether this BufferHubEventFd holds a valid event_fd. 40 */ isValid()41 bool isValid() const { return get() >= 0; } 42 43 /** 44 * Returns the fd number of the BufferHubEventFd object. Note that there is no ownership 45 * transfer. 46 */ get()47 int get() const { return mFd.get(); } 48 49 /** 50 * Signals the eventfd. 51 */ 52 status_t signal() const; 53 54 /** 55 * Clears the signal from this eventfd if it is signaled. 56 */ 57 status_t clear() const; 58 59 private: 60 base::unique_fd mFd; 61 }; 62 63 } // namespace android 64 65 #endif // ANDROID_BUFFER_HUB_EVENT_FD_H_ 66