/******************************************************************************/
/* POINTERS *******************************************************************/
/******************************************************************************/

#include <lw/lib/Alloc.hh>
#include <lw/lib/Config.hh>
#include <lw/lib/Pointers.hh>
using namespace lw;


/*= T_WeakChain_ =============================================================*/

T_WeakChain_::T_WeakChain_( T_Reference_*& ref )
	: ref( &ref ) , prev( nullptr ) , next( nullptr )
{ }

void T_WeakChain_::unchain( )
{
	if ( prev != nullptr ) {
		prev->next = next;
		prev = nullptr;
	} else if ( (*ref) != nullptr ) {
		assert( this == (*ref)->weaks_ );
		(*ref)->weaks_ = next;
	}
	if ( next != nullptr ) {
		next->prev = prev;
		next = nullptr;
	}
}

void T_WeakChain_::init( )
{
	if ( (*ref) == nullptr ) {
		return;
	}
	next = (*ref)->weaks_;
	if ( next != nullptr ) {
		next->prev = this;
	}
	(*ref)->weaks_ = this;
}


/*= T_Reference_ =============================================================*/

namespace {

static T_ThreadedPoolAllocator<
		sizeof( T_Reference_ ) , alignof( T_Reference_ ) ,
		LW_CFG_SHAREDPTR_REFPOOL_SIZE ,
		LW_CFG_SHAREDPTR_REFPOOL_MAXFREE
	> ReferenceAllocator_;

}

void* T_Reference_::operator new(
		const size_t count ) noexcept
{
	return ReferenceAllocator_.allocate( count );
}

void T_Reference_::operator delete(
		void* const object ) noexcept
{
	return ReferenceAllocator_.free( object );
}

/*----------------------------------------------------------------------------*/

T_Reference_::T_Reference_(
		void* const ptr ,
		F_Destr_ destructor )
	: pointer_( ptr ) , destr_( std::move( destructor ) ) ,
		count_( 1 ) , weaks_( nullptr )
{
	assert( pointer_ != nullptr );
}

T_Reference_::~T_Reference_( )
{
	assert( count_ == 0 );
	T_WeakChain_* wr = weaks_;
	while ( wr != nullptr ) {
		T_WeakChain_* const next = wr->next;
		wr->unchain( );
		*( wr->ref ) = nullptr;
		wr = next;
	}
	destr_( pointer_ );
}

void* T_Reference_::extract( )
{
	if ( count_ > 1 ) {
		throw X_TooManyReferences( );
	}
	void* p( pointer_ );
	count_ = 0;
	pointer_ = nullptr;
	delete this;
	return p;
}