From: d.frey_at_[hidden]
Date: 2008-04-26 15:59:11
Author: daniel_frey
Date: 2008-04-26 15:59:11 EDT (Sat, 26 Apr 2008)
New Revision: 44782
URL: http://svn.boost.org/trac/boost/changeset/44782
Log:
Refactored and optimized enable_shared_from_this
Text files modified:
trunk/boost/detail/shared_count.hpp | 5 +
trunk/boost/enable_shared_from_this.hpp | 103 ++++++++++++++++++---------------------
2 files changed, 52 insertions(+), 56 deletions(-)
Modified: trunk/boost/detail/shared_count.hpp
==============================================================================
--- trunk/boost/detail/shared_count.hpp (original)
+++ trunk/boost/detail/shared_count.hpp 2008-04-26 15:59:11 EDT (Sat, 26 Apr 2008)
@@ -373,6 +373,11 @@
return pi_ != 0? pi_->use_count(): 0;
}
+ bool empty() const // nothrow
+ {
+ return pi_ == 0;
+ }
+
friend inline bool operator==(weak_count const & a, weak_count const & b)
{
return a.pi_ == b.pi_;
Modified: trunk/boost/enable_shared_from_this.hpp
==============================================================================
--- trunk/boost/enable_shared_from_this.hpp (original)
+++ trunk/boost/enable_shared_from_this.hpp 2008-04-26 15:59:11 EDT (Sat, 26 Apr 2008)
@@ -13,7 +13,6 @@
// http://www.boost.org/libs/smart_ptr/enable_shared_from_this.html
//
-#include <boost/detail/shared_count.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/assert.hpp>
#include <boost/config.hpp>
@@ -21,35 +20,19 @@
namespace boost
{
-template<class T> class enable_shared_from_this
-{
- void init_internal_shared_once() const
- {
- if( !owned() && _internal_shared_count.empty() )
- {
- detail::shared_count( (void*)0, detail::sp_deleter_wrapper() ).swap(_internal_shared_count);
- _internal_weak_count = _internal_shared_count;
- }
- }
-
- bool owned() const
- {
- return _owned;
- }
-
- mutable detail::shared_count _internal_shared_count;
- mutable detail::weak_count _internal_weak_count;
- mutable bool _owned;
+template< class T > class enable_shared_from_this;
+template< class T, class Y > void sp_accept_owner( shared_ptr<Y> * ptr, enable_shared_from_this<T> const * pe );
+template< class T, class Y > void sp_accept_owner( shared_ptr<Y> * ptr, enable_shared_from_this<T> const * pe, void * /*pd*/ );
+template< class T > class enable_shared_from_this
+{
protected:
- enable_shared_from_this():
- _owned(false)
+ enable_shared_from_this()
{
}
- enable_shared_from_this(enable_shared_from_this const &):
- _owned(false)
+ enable_shared_from_this(enable_shared_from_this const &)
{
}
@@ -64,69 +47,77 @@
// make sure no dangling shared_ptr objects were created by the
// user calling shared_from_this() but never passing ownership of the object
// to a shared_ptr.
- BOOST_ASSERT(owned() || _internal_shared_count.use_count() <= 1);
+ BOOST_ASSERT( _shared_count.use_count() <= 1 );
}
public:
shared_ptr<T> shared_from_this()
{
- init_internal_shared_once();
- T * p = dynamic_cast<T *>(this);
- return shared_ptr<T>( detail::shared_count( _internal_weak_count ), p );
+ init_weak_once();
+ T * p = dynamic_cast<T *>( this );
+ return shared_ptr<T>( detail::shared_count( _weak_count ), p );
}
shared_ptr<T const> shared_from_this() const
{
- init_internal_shared_once();
- T const * p = dynamic_cast<T const *>(this);
- return shared_ptr<T const>( detail::shared_count( _internal_weak_count ), p );
+ init_weak_once();
+ T const * p = dynamic_cast<T const *>( this );
+ return shared_ptr<T const>( detail::shared_count( _weak_count ), p );
+ }
+
+private:
+
+ mutable detail::weak_count _weak_count;
+ mutable detail::shared_count _shared_count;
+
+ void init_weak_once() const
+ {
+ if( _weak_count.empty() )
+ {
+ detail::shared_count( (void*)0, detail::sp_deleter_wrapper() ).swap( _shared_count );
+ _weak_count = _shared_count;
+ }
}
template<typename U>
- void _internal_accept_owner(shared_ptr<U> &owner) const
+ void sp_accept_owner( shared_ptr<U> & owner ) const
{
- if( !_owned )
+ if( _weak_count.use_count() == 0 )
{
- if( _internal_shared_count.empty() )
- {
- _internal_weak_count = owner.get_shared_count();
- }else
- {
- BOOST_ASSERT(owner.unique()); // no weak_ptrs to owner should exist either, but there's no way to check that
- typedef detail::sp_deleter_wrapper D;
- D * pd = static_cast<D *>(_internal_shared_count.get_deleter(BOOST_SP_TYPEID(D)));
- BOOST_ASSERT( pd != 0 );
- pd->set_deleter(owner);
-
- shared_ptr<U>( _internal_shared_count, owner.get() ).swap( owner );
- detail::shared_count().swap(_internal_shared_count);
- }
- _owned = true;
+ _weak_count = owner.get_shared_count();
+ }else if( !_shared_count.empty() )
+ {
+ BOOST_ASSERT( owner.unique() ); // no weak_ptrs to owner should exist either, but there's no way to check that
+ typedef detail::sp_deleter_wrapper D;
+ D * pd = static_cast<D *>( _shared_count.get_deleter( BOOST_SP_TYPEID(D) ) );
+ BOOST_ASSERT( pd != 0 );
+ pd->set_deleter( owner );
+ owner.reset( _shared_count, owner.get() );
+ detail::shared_count().swap( _shared_count );
}
}
+
+ template< class U, class Y > friend void sp_accept_owner( shared_ptr<Y> * ptr, enable_shared_from_this<U> const * pe );
+ template< class U, class Y > friend void sp_accept_owner( shared_ptr<Y> * ptr, enable_shared_from_this<U> const * pe, void * /*pd*/ );
};
-template< class T, class Y > inline void sp_accept_owner( boost::shared_ptr<Y> * ptr, boost::enable_shared_from_this<T> const * pe )
+template< class T, class Y > inline void sp_accept_owner( shared_ptr<Y> * ptr, enable_shared_from_this<T> const * pe )
{
if( pe != 0 )
{
- pe->_internal_accept_owner( *ptr );
+ pe->sp_accept_owner( *ptr );
}
}
-template< class T, class Y > inline void sp_accept_owner( boost::shared_ptr<Y> * ptr, boost::enable_shared_from_this<T> const * pe, void * /*pd*/ )
+template< class T, class Y > inline void sp_accept_owner( shared_ptr<Y> * ptr, enable_shared_from_this<T> const * pe, void * /*pd*/ )
{
if( pe != 0 )
{
- pe->_internal_accept_owner( *ptr );
+ pe->sp_accept_owner( *ptr );
}
}
-template< class T, class Y > inline void sp_accept_owner( boost::shared_ptr<Y> * /*ptr*/, boost::enable_shared_from_this<T> const * /*pe*/, boost::detail::sp_deleter_wrapper * /*pd*/ )
-{
-}
-
} // namespace boost
#endif // #ifndef BOOST_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED