/******************************************************************************/
/* REFERENCE-COUNTING HELPERS *************************************************/
/******************************************************************************/

#ifndef _H_EBCL_REFCOUNT
#define _H_EBCL_REFCOUNT
#include <ebcl/Utilities.hh>
namespace ebcl {

// A base class and pointer type that can be used to implement classes which
// use in-instance reference counters.


/*= REFERENCE-COUNTED INSTANCES ==============================================*/

// Base class containing the reference counter. It may be an atomic, or it
// may be a simple integer.
template< bool UseAtomic = false >
class T_ReferenceCountedClass
{
    public:
	// Is it atomic ?
	static const bool UsingAtomic = UseAtomic;
	// Reference counter type
	using T_ReferenceCounter = std::conditional_t<
			UseAtomic , std::atomic< uint32_t > , uint32_t
		>;

	// Reference-counting pointers can access the counter
	template< typename > friend class T_RcPtr;

    private:
	T_ReferenceCounter referenceCounter_;

	// Add a reference to the counter
	void increaseReferences_( ) noexcept;

	// Remove a reference from the counter, returning true if the instance
	// is no longer referenced.
	bool decreaseReferences_( ) noexcept;

    protected:
	T_ReferenceCountedClass( ) noexcept;
};

// Shortcuts
using T_AtomicRcClass = T_ReferenceCountedClass< true >;
using T_SimpleRcClass = T_ReferenceCountedClass< false >;


/*= REFERENCE-COUNTING POINTERS ==============================================*/

// Pointers that use T_ReferenceCountedClass in order to track the reference
// counts of the instances it manages.
template< typename Type >
class T_RcPtr
{
	static_assert( MetaOr< std::is_base_of< T_AtomicRcClass , Type > ,
			std::is_base_of< T_SimpleRcClass , Type > >::value ,
		"type does not include a reference counter" );

    public:
	// Target type
	using T_Target = Type;
	// Pointer type
	using T_Self = T_RcPtr< Type >;
	// Base reference counting class
	using T_RcClass = std::conditional_t<
			std::is_base_of< T_AtomicRcClass , Type >::value ,
			T_AtomicRcClass , T_SimpleRcClass
		>;

    private:
	T_Target* target_;

    public:

	// ---------------------------------------------------------------------

	T_RcPtr( ) noexcept;
	~T_RcPtr( ) noexcept;

	void clear( ) noexcept;

	// ---------------------------------------------------------------------
	// Copy constructors

	T_RcPtr( T_Self const& other ) noexcept;
	template< typename Q , T_EnableForChild< Type , Q > = true >
		T_RcPtr( T_RcPtr< Q > const& source ) noexcept;
	template< typename Q , T_EnableForParent< Type , Q > = false >
		explicit T_RcPtr( T_RcPtr< Q > const& source );

	// ---------------------------------------------------------------------
	// Move constructors

	template< typename Q , T_EnableForChild< Type , Q > = true >
		T_RcPtr( T_RcPtr< Q >&& other ) noexcept;

	template< typename Q , T_EnableForParent< Type , Q > = false >
		explicit T_RcPtr( T_RcPtr< Q >&& other );
};



} // namespace
#endif // _H_EBCL_REFCOUNT
#include <ebcl/inline/RefCount.hh>