Struct ItemCache

pub struct ItemCache<T> { /* private fields */ }

A per-item cache.

Cache rendering information for a given item.

Use ItemCache::get_or_update_cache_entry to get or update the items, the cache is automatically invalided when the property gets dirty. ItemCache::component_destroyed must be called to clear the cache for that component.

Implementations

impl<T: Clone> ItemCache<T>

pub fn get_or_update_cache_entry( &self, item_rc: &ItemRc, update_fn: impl FnOnce() -> T, ) -> T

Returns the cached value associated to the item_rc if it is still valid. Otherwise call the update_fn to compute that value, and track property access so it is automatically invalided when property becomes dirty.

pub fn with_entry<U>( &self, item_rc: &ItemRc, callback: impl FnOnce(&T) -> Option<U>, ) -> Option<U>

Returns the cached value associated with the item_rc if it is in the cache and still valid.

pub fn clear_cache_if_scale_factor_changed(&self, window: &Window)

Clears the cache if the window’s scale factor has changed since the last call.

pub fn clear_all(&self)

free the whole cache

pub fn component_destroyed(&self, component: ItemTreeRef<'_>)

Function that must be called when a component is destroyed.

Usually can be called from [crate::window::WindowAdapterInternal::unregister_item_tree]

pub fn release(&self, item_rc: &ItemRc)

free the cache for a given item

pub fn is_empty(&self) -> bool

Returns true if there are no entries in the cache; false otherwise.

Trait Implementations

impl<T> Default for ItemCache<T>

fn default() -> Self

Returns the “default value” for a type.