LockGuard.h

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef KERNEL_LOCKGUARD_H
#define KERNEL_LOCKGUARD_H

#include "pedigree/kernel/compiler.h"

class Spinlock;
class Mutex;
class Semaphore;

template <class T>
class EXPORTED_PUBLIC LockGuard
{
  public:
    LockGuard(T &Lock, bool Condition = true)
        : m_Lock(Lock), m_bCondition(Condition)
    {
        if (m_bCondition)
            m_Lock.acquire();
    }
    ~LockGuard()
    {
        if (m_bCondition)
            m_Lock.release();
    }

  private:
    LockGuard() = delete;
    NOT_COPYABLE_OR_ASSIGNABLE(LockGuard);

    T &m_Lock;
    bool m_bCondition;
};

template <class T>
class EXPORTED_PUBLIC RecursingLockGuard
{
  public:
    RecursingLockGuard(T &Lock, bool Condition = true)
        : m_Lock(Lock), m_bCondition(Condition)
    {
        // T::allow_recursion must exist to be able to use RecursingLockGuard.
        if (m_bCondition)
            m_Lock.acquire(T::allow_recursion);
    }
    ~RecursingLockGuard()
    {
        if (m_bCondition)
            m_Lock.release();
    }

  private:
    RecursingLockGuard() = delete;
    NOT_COPYABLE_OR_ASSIGNABLE(RecursingLockGuard);

    T &m_Lock;
    bool m_bCondition;
};

extern template class LockGuard<Spinlock>;
extern template class RecursingLockGuard<Spinlock>;
#ifdef THREADS
extern template class LockGuard<Mutex>;
extern template class LockGuard<Semaphore>;
#endif

#endif