Lock.hxx

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/*
 * Copyright (c) 2004 MUSIC TECHNOLOGY GROUP (MTG)
 *                         UNIVERSITAT POMPEU FABRA
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#ifndef __LOCK__
#define __LOCK__

#include "ErrSystem.hxx"
#include "xtime.hxx"

namespace CLAM
{
        class Condition;
        
        namespace Hidden
        {
                
                using CLAM::xtime;
                                
                template <typename MutexType>
                class LockOps 
                {
                private:
                        LockOps() { }
                        
                public:
                        typedef typename MutexType::ConditionVar LockState;
                        
                        static void Lock(MutexType& m)
                        {
                                m.DoLock();
                        }
                        static bool TryLock(MutexType& m)
                        {
                                return m.DoTryLock();
                        }
                        static bool TimedLock(MutexType& m, const xtime& xt)
                        {
                                return m.DoTimedLock(xt);
                        }
                        static void Unlock(MutexType& m)
                        {
                                m.DoUnlock();
                        }
                        static void Lock(MutexType& m, LockState& state)
                        {
                                m.DoLock(state);
                        }
                        static void Unlock(MutexType& m, LockState& state)
                        {
                                m.DoUnlock(state);
                        }
                };
                
                template <typename MutexType>
                class ScopedLock
                {
                public:
                        typedef MutexType mutex_type;
                        
                        explicit ScopedLock(MutexType& mx, bool initially_locked=true)
                                : mMutex(mx), mLocked(false)
                        {
                                if (initially_locked) 
                                        Lock();
                        }
                        ~ScopedLock()
                        {
                                if (mLocked) 
                                        Unlock();
                        }
                        
                        void Lock()
                        {
                                if (mLocked) 
                                        throw LockError( "Trying to Lock already locked Mutex" );
                                
                                Hidden::LockOps<mutex_type>::Lock(mMutex);
                                mLocked = true;
                        }
                        
                        void Unlock()
                        {
                                if (!mLocked) 
                                        throw LockError("Trying to Unlock already a not yet locked Mutex");
                        
                                LockOps<mutex_type>::Unlock(mMutex);

                                mLocked = false;
                        }

                        bool Locked() const 
                        { 
                                return mLocked; 
                        }

                        operator const void*() const 
                        { 
                                return mLocked ? this : 0; 
                        }

                private:
                        friend class CLAM::Condition;

                        MutexType& mMutex;
                        bool mLocked;
                };

                template <typename TryMutexType>
                class ScopedTryLock 
                {
                public:
                        typedef TryMutexType mutex_type;

                        explicit ScopedTryLock(TryMutexType& mx)
                                : mMutex(mx), mLocked(false)
                        {
                                TryLock();
                        }

                        ScopedTryLock(TryMutexType& mx, bool initially_locked)
                                : mMutex(mx), mLocked(false)
                        {
                                if (initially_locked) 
                                        Lock();
                        }
                
                        ~ScopedTryLock()
                        {
                                if (mLocked) 
                                        Unlock();
                        }

                        void Lock()
                        {
                                if (mLocked) 
                                        throw LockError("Trying to Lock already locked Mutex");
                        
                                LockOps<TryMutexType>::Lock(mMutex);

                                mLocked = true;
                        }

                        bool TryLock()
                        {
                                if (mLocked) 
                                        throw LockError("Trying to Lock already locked Mutex");

                                return (mLocked = LockOps<TryMutexType>::TryLock(mMutex));
                        }
                
                        void Unlock()
                        {
                                if (!mLocked) 
                                        throw LockError("Trying to Unlock already a not yet locked Mutex");
                        
                                LockOps<TryMutexType>::Unlock(mMutex);

                                mLocked = false;
                        }

                        bool Locked() const 
                        { 
                                return mLocked; 
                        }
                
                        operator const void*() const 
                        { 
                                return mLocked ? this : 0; 
                        }

                private:
                
                        friend class CLAM::Condition;

                        TryMutexType& mMutex;
                        bool mLocked;
                };

                template <typename TimedMutexType>
                class ScopedTimedLock 
                {
                public:
                        typedef TimedMutexType mutex_type;

                        ScopedTimedLock(TimedMutexType& mx, const xtime& xt )
                                : mMutex(mx), mLocked(false)
                        {
                        
                                TimedLock(xt);
                        }
                
                        ScopedTimedLock(TimedMutexType& mx, bool initially_locked)
                                : mMutex(mx), mLocked(false)
                        {
                                if (initially_locked) 
                                        Lock();
                        }
                
                        ~ScopedTimedLock()
                        {
                                if (mLocked) 
                                        Unlock();
                        }

                        void Lock()
                        {
                                if (mLocked) 
                                        throw LockError("Trying to Lock already locked Mutex");
                        
                                LockOps<TimedMutexType>::Lock(mMutex);

                                mLocked = true;
                        }

                        bool TimedLock(const xtime& xt)
                        {
                                if (mLocked) 
                                        throw LockError("Trying to Lock already locked Mutex");

                                return (mLocked = LockOps<TimedMutexType>::TimedLock(mMutex, xt));
                        }
                        void Unlock()
                        {
                                if (!mLocked) 
                                        throw LockError("Trying to Unlock already a not yet locked Mutex");

                                LockOps<TimedMutexType>::Unlock(mMutex);
                        
                                mLocked = false;
                        }

                        bool Locked() const 
                        { 
                                return mLocked; 
                        }
                
                        operator const void*() const 
                        { 
                                return mLocked ? this : 0; 
                        }

                private:

                        friend class CLAM::Condition;

                        TimedMutexType& mMutex;
                        bool mLocked;
                };
        
        } // End of namespace Hidden

} // end of namespace CLAM

#endif // Lock.hxx