text: /**************************************************************
   * 
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   * 
   *   http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   * 
   *************************************************************/
  
  
  
  #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;
  }
  