Re: [boost] [smart_ptr] shared_ptr template type

9 Jul 2009


      This was fun to experiment with. Here's another whack at your puzzle.
-Sid Sacek


#include <iostream>
#include <boost/shared_ptr.hpp>

using namespace std;
using boost::shared_ptr;

template< typename T > class monitor;

template< typename T > class locker
{
	shared_ptr< T > shared_obj_;
public:
	locker( shared_ptr< T > &shared_obj ) : shared_obj_( shared_obj
)
	{
		shared_obj_->lock();
	}
	~locker()
	{
		shared_obj_->unlock(); 
	}
	shared_ptr< T > operator->()
	{
		return shared_obj_;
	}
};

template< typename T > class monitor
{
	shared_ptr< T > shared_obj_;
public:
	monitor( T * t ) : shared_obj_( shared_ptr< T >( t ) )
	{ }

	locker< T > operator->()
	{
		return locker< T >( shared_obj_ );
	}
};

struct mutex
{
	void lock()   { cout << "object locked \n"; }
	void unlock() { cout << "object unlocked \n"; }
};

struct Q : mutex
{
	void ModifyObject() { cout << "Object modified \n"; }
};

int main( int argc, char * argv[] )
{
	monitor< Q > m( new Q );
	m->ModifyObject();
	return 0;
}