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