/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*************************************************************************
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 * 
 * Copyright 2000, 2010 Oracle and/or its affiliates.
 *
 * OpenOffice.org - a multi-platform office productivity suite
 *
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 *
 * OpenOffice.org is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 3
 * only, as published by the Free Software Foundation.
 *
 * OpenOffice.org 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 Lesser General Public License version 3 for more details
 * (a copy is included in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU Lesser General Public License
 * version 3 along with OpenOffice.org.  If not, see
 * <http://www.openoffice.org/license.html>
 * for a copy of the LGPLv3 License.
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 ************************************************************************/

#include <sys/fmutex.h>

#include "system.h"

#include <osl/mutex.h>
#include <osl/diagnose.h>

/*
    Implementation notes:
    The void* hidden by oslMutex points to an OS/2 mutex semaphore.
*/
typedef struct _oslMutexImpl {
    HMTX				m_Mutex;
    int 				m_Locks;
    ULONG				m_Owner;
    ULONG				m_Requests;
} oslMutexImpl;

// static mutex to control access to private members of oslMutexImpl
static HMTX MutexLock = 0;

/*****************************************************************************/
/* osl_createMutex */
/*****************************************************************************/
oslMutex SAL_CALL osl_createMutex()
{
    oslMutexImpl *pMutexImpl;
    HMTX hMutex;
    APIRET rc;

    pMutexImpl= (oslMutexImpl*)calloc(sizeof(oslMutexImpl), 1);
    OSL_ASSERT(pMutexImpl); /* alloc successful? */
    
    /* create semaphore */
    rc = DosCreateMutexSem( NULL, &pMutexImpl->m_Mutex, 0, FALSE );
    if( rc != 0 )
    {
        free(pMutexImpl);
        return NULL;
    }

    // create static mutex for private members
    if (MutexLock == 0)
        DosCreateMutexSem( NULL, &MutexLock, 0, FALSE );

    return (oslMutex)pMutexImpl;
}

/*****************************************************************************/
/* osl_destroyMutex */
/*****************************************************************************/
void SAL_CALL osl_destroyMutex(oslMutex Mutex)
{
    oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
    if (pMutexImpl)
    {
        DosCloseMutexSem( pMutexImpl->m_Mutex);
        free(pMutexImpl);
    }
}

/*****************************************************************************/
/* osl_acquireMutex */
/*****************************************************************************/
sal_Bool SAL_CALL osl_acquireMutex(oslMutex Mutex)
{
    oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
    APIRET rc = 0;
    OSL_ASSERT(Mutex);

    DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );
    pMutexImpl->m_Requests++;
    DosReleaseMutexSem( MutexLock);

    rc = DosRequestMutexSem( pMutexImpl->m_Mutex, SEM_INDEFINITE_WAIT );

    DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );
    pMutexImpl->m_Requests--;
    if (pMutexImpl->m_Locks++ == 0)
        pMutexImpl->m_Owner = _gettid();
    DosReleaseMutexSem( MutexLock);

    return( rc == 0 );
}

/*****************************************************************************/
/* osl_tryToAcquireMutex */
/*****************************************************************************/
sal_Bool SAL_CALL osl_tryToAcquireMutex(oslMutex Mutex)
{
    sal_Bool 	 ret = sal_False;
    oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
    OSL_ASSERT(Mutex);

    DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );

    if ( ((pMutexImpl->m_Requests == 0) && (pMutexImpl->m_Locks == 0)) ||
         (pMutexImpl->m_Owner == _gettid()) )
        ret = osl_acquireMutex(Mutex);

    DosReleaseMutexSem( MutexLock);
    
    return ret;
}

/*****************************************************************************/
/* osl_releaseMutex */
/*****************************************************************************/
sal_Bool SAL_CALL osl_releaseMutex(oslMutex Mutex)
{
    oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
    APIRET rc;
    OSL_ASSERT(Mutex);

    DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );

    if (--(pMutexImpl->m_Locks) == 0)
        pMutexImpl->m_Owner = 0;

    DosReleaseMutexSem( MutexLock);

    rc = DosReleaseMutexSem( pMutexImpl->m_Mutex);

    return sal_True;
}



/*****************************************************************************/
/* osl_getGlobalMutex */
/*****************************************************************************/

oslMutex g_Mutex = NULL;

oslMutex * SAL_CALL osl_getGlobalMutex(void) 
{
    if (g_Mutex == NULL)
        g_Mutex = osl_createMutex();
    return &g_Mutex;
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
