// **********************************************************************
//
// Copyright (c) 2000
// Object Oriented Concepts, Inc.
// Billerica, MA, USA
//
// All Rights Reserved
//
// **********************************************************************

#ifndef JTC_MUTEX_H
#define JTC_MUTEX_H

//
// This class can be used to establish a critical section. Call the
// lock method to lock the mutex, and the unlock Method to unlock the
// mutex. If the mutex is currently locked the thread will be
// suspended until the mutex becomes unlocked.
//
class JTCMutex
{
    //
    // Hide copy constructor and assignment operator.
    //
    JTCMutex(const JTCMutex&);
    void operator=(const JTCMutex&);

#if defined(HAVE_POSIX_THREADS) || defined(HAVE_DCE_THREADS)
    pthread_mutex_t lock_; // Pthread mutex.
#endif

#if defined(HAVE_WIN32_THREADS)
    CRITICAL_SECTION crit_; // WIN32 critical section.
#endif

    friend class JTCEvent;

public:

    JTCMutex()
    {
#if defined(HAVE_POSIX_THREADS)
        JTC_SYSCALL_2(pthread_mutex_init, &lock_, 0, != 0)
#endif
#if defined(HAVE_DCE_THREADS)
        JTC_SYSCALL_2(pthread_mutex_init, &lock_, pthread_mutexattr_default,
		      != 0)
#endif
#if defined(HAVE_WIN32_THREADS)
        InitializeCriticalSection(&crit_);
#endif
    }
    ~JTCMutex()
    {
#if defined(HAVE_POSIX_THREADS) || defined(HAVE_DCE_THREADS)
        pthread_mutex_destroy(&lock_);
#endif
#if defined(HAVE_WIN32_THREADS)
        DeleteCriticalSection(&crit_);
#endif
    }

    //
    // Lock the mutex.
    //
    void lock() const
    {
#if defined(HAVE_WIN32_THREADS)
#endif

#if defined(HAVE_POSIX_THREADS) || defined(HAVE_DCE_THREADS)
#if defined(__GNUC__) && defined(__OPTIMIZE__)
	//
	// The optimizer for GCC 2.95.1 is broken. The following
	// three lines of code "fix" the problem.
	//
	volatile int i = 1;
	if (i == 0) 
	    ++i;
#endif
        pthread_mutex_t* lock = &((JTCMutex*)this) -> lock_;
        JTC_SYSCALL_1(pthread_mutex_lock, lock, != 0)
#endif
#if defined(HAVE_WIN32_THREADS)
	CRITICAL_SECTION* crit = &((JTCMutex*)this) -> crit_;
        EnterCriticalSection(crit);
#endif
    }


    //
    // Unlock the mutex.
    //
    void unlock() const
    {
#if defined(HAVE_POSIX_THREADS) || defined(HAVE_DCE_THREADS)
        pthread_mutex_t* lock = &((JTCMutex*)this) -> lock_;
        JTC_SYSCALL_1(pthread_mutex_unlock, lock, != 0)
#endif
#if defined(HAVE_WIN32_THREADS)
	CRITICAL_SECTION* crit = &((JTCMutex*)this) -> crit_;
        LeaveCriticalSection(crit);
#endif

    }
};

//
// Unlike the JTCMutex class this mutex can be locked recursively.
// That is it can be locked by a thread that already has the mutex
// locked.
//
class JTCRecursiveMutex
{
    //
    // Hide copy constructor and assignment operator.
    //
    JTCRecursiveMutex(const JTCRecursiveMutex&);
    void operator=(const JTCRecursiveMutex&);

    //
    // Internal non-const operations since mutable isn't supported
    // on some compilers.
    //
    void lockI(int count);
    void unlockI();

    //
    // Lock the mutex count times.
    //
    void lock(int count) const;

#if defined(HAVE_POSIX_THREADS) || defined(HAVE_DCE_THREADS)
    pthread_mutex_t crit_; // Pthreads mutex.
#endif
#if defined(HAVE_WIN32_THREADS)
    CRITICAL_SECTION crit_; // WIN32 critical section.
#endif
    JTCMutex internal_; // Internal mutex.
 
    int count_; // Number of times the mutex has been aquired.
    JTCThreadId owner_; // Current owner of the mutex.

    friend class JTCCondHelper;
    friend class JTCCond;

public:

    JTCRecursiveMutex();
    ~JTCRecursiveMutex();

    //
    // Lock the mutex.
    //
    void lock() const;
    
    //
    // Unlock the mutex.
    //
    void unlock() const;

    //
    // Get the thread id of the owning thread.
    //
    JTCThreadId _JTC_getId() const;
};

#endif