ripple::SharedWeakUnion< T > Class Template Reference

A combination of a strong and a weak intrusive pointer stored in the space of a single pointer. More...

#include <IntrusivePointer.h>

Collaboration diagram for ripple::SharedWeakUnion< T >:

Public Member Functions
	SharedWeakUnion ()=default
	SharedWeakUnion (SharedWeakUnion const &rhs)
template<class TT > requires std::convertible_to<TT*, T*>
	SharedWeakUnion (SharedIntrusive< TT > const &rhs)
	SharedWeakUnion (SharedWeakUnion &&rhs)
template<class TT > requires std::convertible_to<TT*, T*>
	SharedWeakUnion (SharedIntrusive< TT > &&rhs)
SharedWeakUnion &	operator= (SharedWeakUnion const &rhs)
template<class TT > requires std::convertible_to<TT*, T*>
SharedWeakUnion &	operator= (SharedIntrusive< TT > const &rhs)
template<class TT > requires std::convertible_to<TT*, T*>
SharedWeakUnion &	operator= (SharedIntrusive< TT > &&rhs)
	~SharedWeakUnion ()
SharedIntrusive< T >	getStrong () const
	Return a strong pointer if this is already a strong pointer (i.e.
	operator bool () const noexcept
	Return true if this is a strong pointer and the strong pointer is seated.
void	reset ()
	Set the pointer to null, decrement the appropriate ref count, and run the appropriate release action.
T *	get () const
	If this is a strong pointer, return the raw pointer.
std::size_t	use_count () const
	If this is a strong pointer, return the strong count.
bool	expired () const
	Return true if there is a non-zero strong count.
SharedIntrusive< T >	lock () const
	If this is a strong pointer, return the strong pointer.
bool	isStrong () const
	Return true is this represents a strong pointer.
bool	isWeak () const
	Return true is this represents a weak pointer.
bool	convertToStrong ()
	If this is a weak pointer, attempt to convert it to a strong pointer.
bool	convertToWeak ()
	If this is a strong pointer, attempt to convert it to a weak pointer.

Private Types
enum class	RefStrength { strong , weak }

Private Member Functions
T *	unsafeGetRawPtr () const
	Return the raw pointer held by this object.
void	unsafeSetRawPtr (T *p, RefStrength rs)
	Set the raw pointer and tag bit directly.
void	unsafeSetRawPtr (std::nullptr_t)
	Set the raw pointer and tag bit to all zeros (strong null pointer).
void	unsafeReleaseNoStore ()
	Decrement the appropriate ref count, and run the appropriate release action.

Private Attributes
std::uintptr_t	tp_ {0}

Static Private Attributes
static constexpr std::uintptr_t	tagMask = 1
static constexpr std::uintptr_t	ptrMask = ~tagMask

Detailed Description

template<class T>
class ripple::SharedWeakUnion< T >

A combination of a strong and a weak intrusive pointer stored in the space of a single pointer.

This class is similar to a std::variant<SharedIntrusive,WeakIntrusive> with some optimizations. In particular, it uses a low-order bit to determine if the raw pointer represents a strong pointer or a weak pointer. It can also be quickly switched between its strong pointer and weak pointer representations. This class is useful for storing intrusive pointers in tagged caches.

Definition at line 321 of file IntrusivePointer.h.

Member Enumeration Documentation

RefStrength

template<class T >

enum class ripple::SharedWeakUnion::RefStrength

strongprivate

Enumerator
strong
weak

Definition at line 440 of file IntrusivePointer.h.

Constructor & Destructor Documentation

SharedWeakUnion() [1/5]

template<class T >

ripple::SharedWeakUnion< T >::SharedWeakUnion ( )

default

SharedWeakUnion() [2/5]

template<class T >

ripple::SharedWeakUnion< T >::SharedWeakUnion

(

SharedWeakUnion< T > const &

rhs

)

SharedWeakUnion() [3/5]

template<class T >

template<class TT >
requires std::convertible_to<TT*, T*>

ripple::SharedWeakUnion< T >::SharedWeakUnion

(

SharedIntrusive< TT > const &

rhs

)

SharedWeakUnion() [4/5]

template<class T >

ripple::SharedWeakUnion< T >::SharedWeakUnion

(

SharedWeakUnion< T > &&

rhs

)

SharedWeakUnion() [5/5]

template<class T >

template<class TT >
requires std::convertible_to<TT*, T*>

ripple::SharedWeakUnion< T >::SharedWeakUnion

(

SharedIntrusive< TT > &&

rhs

)

~SharedWeakUnion()

template<class T >

ripple::SharedWeakUnion< T >::~SharedWeakUnion

(

)

Member Function Documentation

operator=() [1/3]

template<class T >

SharedWeakUnion & ripple::SharedWeakUnion< T >::operator=

(

SharedWeakUnion< T > const &

rhs

)

operator=() [2/3]

template<class T >

template<class TT >
requires std::convertible_to<TT*, T*>

SharedWeakUnion & ripple::SharedWeakUnion< T >::operator=

(

SharedIntrusive< TT > const &

rhs

)

operator=() [3/3]

template<class T >

template<class TT >
requires std::convertible_to<TT*, T*>

SharedWeakUnion & ripple::SharedWeakUnion< T >::operator=

(

SharedIntrusive< TT > &&

rhs

)

getStrong()

template<class T >

SharedIntrusive< T > ripple::SharedWeakUnion< T >::getStrong

(

)

const

Return a strong pointer if this is already a strong pointer (i.e.

don't lock the weak pointer. Use the lock method if that's what's needed)

operator bool()

template<class T >

ripple::SharedWeakUnion< T >::operator bool ( ) const

explicitnoexcept

Return true if this is a strong pointer and the strong pointer is seated.

reset()

template<class T >

void ripple::SharedWeakUnion< T >::reset

(

)

Set the pointer to null, decrement the appropriate ref count, and run the appropriate release action.

get()

template<class T >

T * ripple::SharedWeakUnion< T >::get

(

)

const

If this is a strong pointer, return the raw pointer.

Otherwise return null.

use_count()

template<class T >

std::size_t ripple::SharedWeakUnion< T >::use_count

(

)

const

If this is a strong pointer, return the strong count.

Otherwise return 0

expired()

template<class T >

bool ripple::SharedWeakUnion< T >::expired

(

)

const

Return true if there is a non-zero strong count.

lock()

template<class T >

SharedIntrusive< T > ripple::SharedWeakUnion< T >::lock

(

)

const

If this is a strong pointer, return the strong pointer.

Otherwise attempt to lock the weak pointer.

isStrong()

template<class T >

bool ripple::SharedWeakUnion< T >::isStrong

(

)

const

Return true is this represents a strong pointer.

isWeak()

template<class T >

bool ripple::SharedWeakUnion< T >::isWeak

(

)

const

Return true is this represents a weak pointer.

convertToStrong()

template<class T >

bool ripple::SharedWeakUnion< T >::convertToStrong

(

)

If this is a weak pointer, attempt to convert it to a strong pointer.

Returns

true if successfully converted to a strong pointer (or was already a strong pointer). Otherwise false.

convertToWeak()

template<class T >

bool ripple::SharedWeakUnion< T >::convertToWeak

(

)

If this is a strong pointer, attempt to convert it to a weak pointer.

Returns

false if the pointer is null. Otherwise return true.

unsafeGetRawPtr()

template<class T >

T * ripple::SharedWeakUnion< T >::unsafeGetRawPtr ( ) const

private

Return the raw pointer held by this object.

unsafeSetRawPtr() [1/2]

template<class T >

void ripple::SharedWeakUnion< T >::unsafeSetRawPtr ( T *  p, RefStrength  rs  )

private

Set the raw pointer and tag bit directly.

unsafeSetRawPtr() [2/2]

template<class T >

void ripple::SharedWeakUnion< T >::unsafeSetRawPtr ( std::nullptr_t  )

private

Set the raw pointer and tag bit to all zeros (strong null pointer).

unsafeReleaseNoStore()

template<class T >

void ripple::SharedWeakUnion< T >::unsafeReleaseNoStore ( )

private

Decrement the appropriate ref count, and run the appropriate release action.

Note: this does not set the raw pointer to null.

Member Data Documentation

tp_

template<class T >

std::uintptr_t ripple::SharedWeakUnion< T >::tp_ {0}

private

Definition at line 430 of file IntrusivePointer.h.

tagMask

template<class T >

constexpr std::uintptr_t ripple::SharedWeakUnion< T >::tagMask = 1

staticconstexprprivate

Definition at line 431 of file IntrusivePointer.h.

ptrMask

template<class T >

constexpr std::uintptr_t ripple::SharedWeakUnion< T >::ptrMask = ~tagMask

staticconstexprprivate

Definition at line 432 of file IntrusivePointer.h.