ut_mutexImpl.h

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/* -*- mode: C++; tab-width: 4; c-basic-offset: 4; -*- */

/* AbiSource Program Utilities
 * Copyright (C) 2002 Dom Lachowicz <cinamod@hotmail.com>
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 */

#ifndef UT_MUTEXIMPL_H
#define UT_MUTEXIMPL_H

#include <glib.h>
#include "ut_assert.h"

class UT_MutexImpl
{
public:

    UT_MutexImpl ()
        : mMutex ( 0 )
        {
#if GLIB_CHECK_VERSION(2,32,0)
            mMutex = &mStaticMutex;
            g_mutex_init(&mStaticMutex);
#else
            if (!g_thread_supported ())
                g_thread_init (NULL);
            mMutex = g_mutex_new () ;
            UT_ASSERT ( mMutex ) ;
#endif
        }

    ~UT_MutexImpl ()
        {
#if GLIB_CHECK_VERSION(2,32,0)
            g_mutex_clear(&mStaticMutex);
#else
            if ( mMutex )
                g_mutex_free ( mMutex ) ;
#endif
        }

  void lock ()
        {
            if ( mMutex && mLocker != g_thread_self())
                g_mutex_lock ( mMutex ) ;
            mLocker = g_thread_self();
            iLockCount++;
        }

  void unlock ()
        {
            UT_ASSERT(mLocker == g_thread_self());
            if (--iLockCount == 0 && mMutex)
                g_mutex_unlock ( mMutex ) ;
        }

private:

    // no impls
    UT_MutexImpl (const UT_MutexImpl & other);
    UT_MutexImpl & operator=(const UT_MutexImpl & other);

// TODO: when we require Glib 2.32 or up, we can remove all that
// junk and just keep the static mutex.
#if GLIB_CHECK_VERSION(2,32,0)
    GMutex mStaticMutex;
#endif
    GMutex *mMutex;

    // Damn it, recursive locking is not guaranteed.
    GThread *mLocker;
    int iLockCount;
};

#endif /* UT_MUTEXIMPL_H */