toast::_detail::ControlBox Struct Reference

Reference-count control block embedded inside the Node allocation. More...

#include <control_box.hpp>

Collaboration diagram for toast::_detail::ControlBox:

Public Member Functions
	ControlBox (Node *n)
	Initializes ref_count to 1 and stores the node pointer; called by nodeAllocation().
	ControlBox (const ControlBox &)=delete
	ControlBox (ControlBox &&)=delete
auto	operator= (const ControlBox &) -> ControlBox &=delete
auto	operator= (ControlBox &&) -> ControlBox &=delete
	operator bool () const noexcept
	Returns true when the node pointer is non-null, i.e. the node has not been freed.
auto	operator<=> (const ControlBox &other) const noexcept -> std::strong_ordering
	Total order over ControlBox identity; compares by rid() so boxes sort consistently in maps.
auto	operator== (const ControlBox &other) const noexcept -> bool
auto	rid () const noexcept -> std::uintptr_t
	Stable numeric identity for this ControlBox.
void	increment ()
	relaxed acquire; acquiring a Box is always preceded by an acquire elsewhere
void	decrement ()
	acq_rel release; ensures the last releaser sees all prior writes before decrementing

Static Public Member Functions
static auto	get (const Node *node) -> ControlBox *
	Recovers the ControlBox from a raw node pointer; the ControlBox sits immediately before the Node in memory.
static auto	get (const Node &node) -> ControlBox *
	Recovers the ControlBox from a node reference; equivalent to get(&node).

Public Attributes
std::atomic< unsigned int >	ref_count
	starts at 1 (the node's self-reference); node is freed when it hits 0
Node *	node = nullptr
	null once the node is destroyed

Detailed Description

Reference-count control block embedded inside the Node allocation.

Lives immediately before the Node in a single contiguous heap block so that Box<Node> handles need no separate allocation. ControlBox is an implementation detail; user code should interact exclusively through Box<Node>.

Note

Copy and move are deleted: the ControlBox must never move in memory because all Box handles hold raw pointers to it

Member Function Documentation

rid()

auto toast::_detail::ControlBox::rid ( ) const -> std::uintptr_t

nodiscardnoexcept

Stable numeric identity for this ControlBox.

Returns

The ControlBox address cast to uintptr_t; stable for the lifetime of the node; used as a hash key in the dependency graph maps

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The documentation for this struct was generated from the following files:

• engine/src/toast/world/control_box.hpp
• engine/src/toast/world/control_box.cpp