1 /* 2 * Copyright (C) 2010 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 ASYNCHRONOUS_CLOSE_MONITOR_H_included 18 #define ASYNCHRONOUS_CLOSE_MONITOR_H_included 19 20 #include "ScopedPthreadMutexLock.h" 21 #include <pthread.h> 22 23 /** 24 * AsynchronousCloseMonitor helps implement Java's asynchronous close semantics. 25 * 26 * AsynchronousCloseMonitor::init must be called before anything else. 27 * 28 * Every blocking I/O operation must be surrounded by an AsynchronousCloseMonitor 29 * instance. For example: 30 * 31 * { 32 * AsynchronousCloseMonitor monitor(fd); 33 * byteCount = ::read(fd, buf, sizeof(buf)); 34 * } 35 * 36 * To interrupt all threads currently blocked on file descriptor 'fd', call signalBlockedThreads: 37 * 38 * AsynchronousCloseMonitor::signalBlockedThreads(fd); 39 * 40 * To test to see if the interruption was due to the signalBlockedThreads call: 41 * 42 * monitor.wasSignaled(); 43 */ 44 class AsynchronousCloseMonitor { 45 public: 46 AsynchronousCloseMonitor(int fd); 47 ~AsynchronousCloseMonitor(); 48 bool wasSignaled() const; 49 50 static void init(); 51 52 static void signalBlockedThreads(int fd); 53 54 private: 55 AsynchronousCloseMonitor* mPrev; 56 AsynchronousCloseMonitor* mNext; 57 pthread_t mThread; 58 int mFd; 59 bool mSignaled; 60 61 // Disallow copy and assignment. 62 AsynchronousCloseMonitor(const AsynchronousCloseMonitor&); 63 void operator=(const AsynchronousCloseMonitor&); 64 }; 65 66 #endif // ASYNCHRONOUS_CLOSE_MONITOR_H_included 67
