/* * Copyright (C) 2007 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef _LIBS_UTILS_RWLOCK_H #define _LIBS_UTILS_RWLOCK_H #include <stdint.h> #include <sys/types.h> #if !defined(_WIN32) # include <pthread.h> #endif #include <utils/Errors.h> #include <utils/ThreadDefs.h> // --------------------------------------------------------------------------- namespace android { // --------------------------------------------------------------------------- #if !defined(_WIN32) /* * Simple mutex class. The implementation is system-dependent. * * The mutex must be unlocked by the thread that locked it. They are not * recursive, i.e. the same thread can't lock it multiple times. */ class RWLock { public: enum { PRIVATE = 0, SHARED = 1 }; RWLock(); explicit RWLock(const char* name); explicit RWLock(int type, const char* name = nullptr); ~RWLock(); status_t readLock(); status_t tryReadLock(); status_t writeLock(); status_t tryWriteLock(); void unlock(); class AutoRLock { public: inline explicit AutoRLock(RWLock& rwlock) : mLock(rwlock) { mLock.readLock(); } inline ~AutoRLock() { mLock.unlock(); } private: RWLock& mLock; }; class AutoWLock { public: inline explicit AutoWLock(RWLock& rwlock) : mLock(rwlock) { mLock.writeLock(); } inline ~AutoWLock() { mLock.unlock(); } private: RWLock& mLock; }; private: // A RWLock cannot be copied RWLock(const RWLock&); RWLock& operator = (const RWLock&); pthread_rwlock_t mRWLock; }; inline RWLock::RWLock() { pthread_rwlock_init(&mRWLock, nullptr); } inline RWLock::RWLock(__attribute__((unused)) const char* name) { pthread_rwlock_init(&mRWLock, nullptr); } inline RWLock::RWLock(int type, __attribute__((unused)) const char* name) { if (type == SHARED) { pthread_rwlockattr_t attr; pthread_rwlockattr_init(&attr); pthread_rwlockattr_setpshared(&attr, PTHREAD_PROCESS_SHARED); pthread_rwlock_init(&mRWLock, &attr); pthread_rwlockattr_destroy(&attr); } else { pthread_rwlock_init(&mRWLock, nullptr); } } inline RWLock::~RWLock() { pthread_rwlock_destroy(&mRWLock); } inline status_t RWLock::readLock() { return -pthread_rwlock_rdlock(&mRWLock); } inline status_t RWLock::tryReadLock() { return -pthread_rwlock_tryrdlock(&mRWLock); } inline status_t RWLock::writeLock() { return -pthread_rwlock_wrlock(&mRWLock); } inline status_t RWLock::tryWriteLock() { return -pthread_rwlock_trywrlock(&mRWLock); } inline void RWLock::unlock() { pthread_rwlock_unlock(&mRWLock); } #endif // !defined(_WIN32) // --------------------------------------------------------------------------- } // namespace android // --------------------------------------------------------------------------- #endif // _LIBS_UTILS_RWLOCK_H