camera/hal/intel/ipu6/src/iutils/RWLock.h

/*
 * Copyright (C) 2007 The Android Open Source Project
 * Copyright (C) 2015-2018 Intel Corporation
 *
 * 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.
 */

#pragma once

#include "Errors.h"

#if defined(HAVE_PTHREADS)
#include <pthread.h>
#endif

// ---------------------------------------------------------------------------
namespace icamera {
// ---------------------------------------------------------------------------

#if defined(HAVE_PTHREADS)

/*
 * 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:
                RWLock() {};
                ~RWLock();

    status_t    readLock();
    status_t    tryReadLock();
    status_t    writeLock();
    status_t    tryWriteLock();
    void        unlock();

    class AutoRLock {
    public:
        inline AutoRLock(RWLock& rwlock) : mLock(rwlock)  { mLock.readLock(); }
        inline ~AutoRLock() { mLock.unlock(); }
    private:
        RWLock& mLock;
    };

    class AutoWLock {
    public:
        inline 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 = PTHREAD_RWLOCK_INITIALIZER;
};

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 // HAVE_PTHREADS
typedef RWLock::AutoRLock AutoRMutex;
typedef RWLock::AutoWLock AutoWMutex;

// ---------------------------------------------------------------------------
} // namespace icamera
// ---------------------------------------------------------------------------