singletonholder.inl

sip 开源代码 源于novell sip 开源代码 源于novell

/*
 *    Copyright (c) <2002-2004> <Jean-Philippe Barrette-LaPierre>
 *    
 *    Permission is hereby granted, free of charge, to any person obtaining
 *    a copy of this software and associated documentation files 
 *    (cURLpp), to deal in the Software without restriction, 
 *    including without limitation the rights to use, copy, modify, merge,
 *    publish, distribute, sublicense, and/or sell copies of the Software,
 *    and to permit persons to whom the Software is furnished to do so, 
 *    subject to the following conditions:
 *    
 *    The above copyright notice and this permission notice shall be included
 *    in all copies or substantial portions of the Software.
 *    
 *    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 *    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
 *    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 
 *    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
 *    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 *    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef SINGLETON_HOLDER_INL
#define SINGLETON_HOLDER_INL

template
<
class T,
template < class > class CreationPolicy,
template < class > class LifetimePolicy,
template < class > class ThreadingModel
>
T&
utilspp::SingletonHolder
<
T,
CreationPolicy,
LifetimePolicy,
ThreadingModel
>
::instance()
{
    if ( mInstance == NULL )
    {
        makeInstance();
    }

    return ( *mInstance );
}

template
<
class T,
template < class > class CreationPolicy,
template < class > class LifetimePolicy,
template < class > class ThreadingModel
>
void
utilspp::SingletonHolder
<
T,
CreationPolicy,
LifetimePolicy,
ThreadingModel
>::makeInstance()
{
    if ( mInstance == NULL )
    {
	typename ThreadingModel< T >::lock guard;
        (void)guard;

	if ( mInstance == NULL ) {
            if ( mDestroyed )
            {
                LifetimePolicy< T >::onDeadReference();
                mDestroyed = false;
            }
            
            mInstance = CreationPolicy< T >::create();
            LifetimePolicy< T >::scheduleDestruction( mInstance, &destroySingleton );
        }
    }
}

template
<
class T,
template < class > class CreationPolicy,
template < class > class LifetimePolicy,
template < class > class ThreadingModel
>
void
utilspp::SingletonHolder
<
T,
CreationPolicy,
LifetimePolicy,
ThreadingModel
>
::destroySingleton()
{
    assert( !mDestroyed );
    CreationPolicy< T >::destroy( mInstance );
    mInstance = NULL;
    mDestroyed = true;
}

template < class T,
template < class > class C,
template < class > class L,
template < class > class M
>
typename utilspp::SingletonHolder< T, C, L, M>::InstanceType
utilspp::SingletonHolder< T, C, L, M >::mInstance;

template
<
class T,
template < class > class C,
template < class > class L,
template < class > class M
>
bool utilspp::SingletonHolder< T, C, L, M >::mDestroyed;

#endif