SceneItemRegistry Class Reference

Owns the id↔item bookkeeping for a Scene: the id-to-item map and the monotonically increasing last-assigned id. More...

#include <SceneItemRegistry.h>

Public Member Functions
bool	contains (int id) const
	Returns true if an item is registered under id.
void	forget (ItemWithId *item)
void	forgetItemId (int id)
ItemWithId *	itemById (int id) const
	Returns the item registered under id, or nullptr.
int	lastId () const
	Returns the highest id assigned so far.
int	nextId ()
	Returns a fresh, previously unused id.
void	registerItem (ItemWithId *item)
	Registers item under its current id.
void	setLastId (int newLastId)
	Raises the last-assigned id to newLastId (never lowers it).
void	unregisterItem (ItemWithId *item)
	Removes item's mapping from the registry.
void	updateItemId (ItemWithId *item, int newId)
	Pre-assigns newId to item before it is added (undo/redo restore path).
	~SceneItemRegistry ()

Detailed Description

Owns the id↔item bookkeeping for a Scene: the id-to-item map and the monotonically increasing last-assigned id.

Extracted from Scene. Pure data structure with no back-reference to the scene; Scene forwards its itemById/nextId/register/… API here. Keeping the invariant (one id ↔ one live item) local makes the registry independently testable.

Definition at line 23 of file SceneItemRegistry.h.

Constructor & Destructor Documentation

~SceneItemRegistry()

SceneItemRegistry::~SceneItemRegistry

(

)

Nulls the registry back-pointer on every item still mapped, so a later cascade-delete (e.g. Qt's ~QGraphicsScene teardown of remaining items, which runs after this registry – a Scene member – has already been destroyed) can't call back into a dangling SceneItemRegistry via ItemWithId's destructor.

Definition at line 89 of file SceneItemRegistry.cpp.

Member Function Documentation

contains()

bool SceneItemRegistry::contains ( int id ) const

nodiscard

Returns true if an item is registered under id.

Definition at line 17 of file SceneItemRegistry.cpp.

forget()

void SceneItemRegistry::forget

(

ItemWithId *

item

)

Removes item's mapping if it is still the one on file, identity-checked so a reused id that a new item has since claimed is never evicted. Called from ItemWithId's own destructor – this is the structural fix for the WIREDPANDA-HC stale-registry-entry bug family, working on ANY destruction path, not just the ones that happen to route through unregisterItem()/forgetItemId() explicitly.

Definition at line 77 of file SceneItemRegistry.cpp.

References ItemWithId::id().

forgetItemId()

void SceneItemRegistry::forgetItemId

(

int

id

)

Removes the mapping for id, clearing the mapped item's registry back-pointer if one is still found. Safe unconditionally: the RAII self-unregistration in ItemWithId's destructor guarantees this registry never holds an entry pointing at an already-destroyed item, so whatever is found here (if anything) is live.

Definition at line 45 of file SceneItemRegistry.cpp.

itemById()

ItemWithId * SceneItemRegistry::itemById ( int id ) const

nodiscard

Returns the item registered under id, or nullptr.

Definition at line 12 of file SceneItemRegistry.cpp.

lastId()

int SceneItemRegistry::lastId

(

)

const

Returns the highest id assigned so far.

Definition at line 22 of file SceneItemRegistry.cpp.

nextId()

int SceneItemRegistry::nextId

(

)

Returns a fresh, previously unused id.

Definition at line 32 of file SceneItemRegistry.cpp.

registerItem()

void SceneItemRegistry::registerItem

(

ItemWithId *

item

)

Registers item under its current id.

Definition at line 53 of file SceneItemRegistry.cpp.

References ItemWithId::id().

setLastId()

void SceneItemRegistry::setLastId

(

int

newLastId

)

Raises the last-assigned id to newLastId (never lowers it).

Definition at line 27 of file SceneItemRegistry.cpp.

Referenced by updateItemId().

unregisterItem()

void SceneItemRegistry::unregisterItem

(

ItemWithId *

item

)

Removes item's mapping from the registry.

Definition at line 66 of file SceneItemRegistry.cpp.

References ItemWithId::id().

updateItemId()

void SceneItemRegistry::updateItemId	(	ItemWithId *	item,
		int	newId )

Pre-assigns newId to item before it is added (undo/redo restore path).

Definition at line 37 of file SceneItemRegistry.cpp.

References ItemWithId::setId(), and setLastId().

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

• SceneItemRegistry.h
• SceneItemRegistry.cpp