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VTable

vortex_layout::vtable

Trait VTable 

Source 
pub trait VTable:
    'static
    + Sized
    + Send
    + Sync
    + Debug {
    type Layout: 'static + Send + Sync + Clone + Debug + Deref<Target = dyn Layout> + IntoLayout;
    type Encoding: 'static + Send + Sync + Deref<Target = dyn LayoutEncoding>;
    type Metadata: SerializeMetadata + DeserializeMetadata + Debug;

    // Required methods
    fn id(encoding: &Self::Encoding) -> LayoutId;
    fn encoding(layout: &Self::Layout) -> LayoutEncodingRef;
    fn row_count(layout: &Self::Layout) -> u64;
    fn dtype(layout: &Self::Layout) -> &DType;
    fn metadata(layout: &Self::Layout) -> Self::Metadata;
    fn segment_ids(layout: &Self::Layout) -> Vec<SegmentId>;
    fn nchildren(layout: &Self::Layout) -> usize;
    fn child(layout: &Self::Layout, idx: usize) -> VortexResult<LayoutRef>;
    fn child_type(layout: &Self::Layout, idx: usize) -> LayoutChildType;
    fn new_reader(
        layout: &Self::Layout,
        name: Arc<str>,
        segment_source: Arc<dyn SegmentSource>,
        session: &VortexSession,
        ctx: &LayoutReaderContext,
    ) -> VortexResult<LayoutReaderRef>;
    fn build(
        encoding: &Self::Encoding,
        dtype: &DType,
        row_count: u64,
        metadata: &<Self::Metadata as DeserializeMetadata>::Output,
        segment_ids: Vec<SegmentId>,
        children: &dyn LayoutChildren,
        build_ctx: &LayoutBuildContext<'_>,
    ) -> VortexResult<Self::Layout>;

    // Provided method
    fn with_children(
        _layout: &mut Self::Layout,
        _children: Vec<LayoutRef>,
    ) -> VortexResult<()> { ... }
}
Expand description

Typed implementation contract for a layout encoding.

A layout vtable connects a concrete layout node type, its registered encoding object, and the metadata representation used for serialization. The object-safe Layout and LayoutEncoding APIs delegate to this trait through adapters.

Required Associated Types§

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type Layout: 'static + Send + Sync + Clone + Debug + Deref<Target = dyn Layout> + IntoLayout

Concrete layout node type for this encoding.

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type Encoding: 'static + Send + Sync + Deref<Target = dyn LayoutEncoding>

Concrete encoding object registered in the session.

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type Metadata: SerializeMetadata + DeserializeMetadata + Debug

Serialized layout metadata type.

Required Methods§

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fn id(encoding: &Self::Encoding) -> LayoutId

Returns the ID of the layout encoding.

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fn encoding(layout: &Self::Layout) -> LayoutEncodingRef

Returns the encoding for the layout.

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fn row_count(layout: &Self::Layout) -> u64

Returns the row count for the layout.

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fn dtype(layout: &Self::Layout) -> &DType

Returns the dtype for the layout reader.

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fn metadata(layout: &Self::Layout) -> Self::Metadata

Returns the metadata for the layout.

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fn segment_ids(layout: &Self::Layout) -> Vec<SegmentId>

Returns the segment IDs for the layout.

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fn nchildren(layout: &Self::Layout) -> usize

Returns the number of children for the layout.

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fn child(layout: &Self::Layout, idx: usize) -> VortexResult<LayoutRef>

Return the child at the given index.

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fn child_type(layout: &Self::Layout, idx: usize) -> LayoutChildType

Return the type of the child at the given index.

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fn new_reader( layout: &Self::Layout, name: Arc<str>, segment_source: Arc<dyn SegmentSource>, session: &VortexSession, ctx: &LayoutReaderContext, ) -> VortexResult<LayoutReaderRef>

Create a new reader for the layout.

Layouts with children MUST propagate ctx to descendants by passing it through Layout::new_reader (or LazyReaderChildren::new) when constructing child readers. If ctx is dropped at any link in the chain, ancestor-published values won’t reach affected descendants — a silent runtime regression for any descendant that looked up an ancestor-published value via ctx.get::<T>(). There is no compile-time check that catches this; reviewer discipline + the integration tests in vortex-layout are the only safety net.

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fn build( encoding: &Self::Encoding, dtype: &DType, row_count: u64, metadata: &<Self::Metadata as DeserializeMetadata>::Output, segment_ids: Vec<SegmentId>, children: &dyn LayoutChildren, build_ctx: &LayoutBuildContext<'_>, ) -> VortexResult<Self::Layout>

Construct a new Layout from deserialized parts.

Implementations should validate child count, child types, row counts, segment references, and dtype consistency for their encoding. The generic adapter checks the returned layout’s top-level dtype and row count, but encoding-specific invariants belong here.

Provided Methods§

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fn with_children( _layout: &mut Self::Layout, _children: Vec<LayoutRef>, ) -> VortexResult<()>

Replaces the children of the layout with the given layout references.

The count and types of children must match the layout’s requirements. This method is used for transforming layout trees by replacing child layouts.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§