Struct LayoutReaderContext 

pub struct LayoutReaderContext { /* private fields */ }

Per-reader-tree dependency context, threaded through crate::VTable::new_reader.

Holds an Id-keyed registry of Arc<dyn Any> values. Ancestors publish via Self::with; descendants retrieve via Self::get. This is a read-only channel from the descendant’s perspective — they can only consume what an ancestor chose to publish.

Self::with returns a derived context that copies the existing map and inserts or replaces one entry — original unchanged, so concurrent reader-tree constructions each derive their own context without races. Contexts are cheap to clone via internal Arc and can be captured by lazy children helpers.

Implementations

impl LayoutReaderContext

pub fn new() -> Self

Creates a new, empty context.

pub fn with<T: Any + Send + Sync>(&self, id: Id, value: Arc<T>) -> Self

Returns a new context that publishes value under id.

The original context is unchanged. If a value was already published under the same id, the new one replaces it in the returned context — so two ancestors using the same well-known static id give descendants “nearest ancestor wins”.

pub fn get<T: Any + Send + Sync>(&self, id: Id) -> Option<Arc<T>>

Returns the value published under id, downcast to T. Returns None if no ancestor published under that id, or if the published value is not a T.

Trait Implementations

impl Clone for LayoutReaderContext

fn clone(&self) -> LayoutReaderContext

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LayoutReaderContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for LayoutReaderContext

fn default() -> LayoutReaderContext

Returns the “default value” for a type.