Trait Layout

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pub trait Layout:
    'static
    + Send
    + Sync
    + Debug
    + Sealed {
    // Required methods
    fn as_any(&self) -> &dyn Any;
    fn as_any_arc(self: Arc<Self>) -> Arc<dyn Any + Send + Sync> ⓘ;
    fn to_layout(&self) -> LayoutRef;
    fn encoding(&self) -> LayoutEncodingRef;
    fn row_count(&self) -> u64;
    fn dtype(&self) -> &DType;
    fn nchildren(&self) -> usize;
    fn child(&self, idx: usize) -> VortexResult<LayoutRef>;
    fn child_type(&self, idx: usize) -> LayoutChildType;
    fn metadata(&self) -> Vec<u8> ⓘ;
    fn segment_ids(&self) -> Vec<SegmentId>;
    fn new_reader(
        &self,
        name: Arc<str>,
        segment_source: Arc<dyn SegmentSource>,
        session: &VortexSession,
        ctx: &LayoutReaderContext,
    ) -> VortexResult<LayoutReaderRef>;
}

Expand description

Erased layout tree node.

A layout is immutable metadata describing how row data is organized into child layouts and physical byte segments. It is self-describing only when paired with the session registries used to deserialize its encoding ids and the segment source used to read bytes.

Required Methods§

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fn as_any(&self) -> &dyn Any

Returns this layout as Any for downcasting through the dyn Layout helpers.

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fn as_any_arc(self: Arc<Self>) -> Arc<dyn Any + Send + Sync> ⓘ

Converts an owned layout reference into erased Any for Arc downcasting.

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fn to_layout(&self) -> LayoutRef

Clone this layout as an erased LayoutRef.

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fn encoding(&self) -> LayoutEncodingRef

Returns the crate::LayoutEncoding for this layout.

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fn row_count(&self) -> u64

The number of rows in this layout.

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fn dtype(&self) -> &DType

The logical dtype of this layout when evaluated at the root scope.

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fn nchildren(&self) -> usize

The number of children in this layout.

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fn child(&self, idx: usize) -> VortexResult<LayoutRef>

Get the child at the given index.

Child ordering and meaning are encoding-specific and described by child_type.

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fn child_type(&self, idx: usize) -> LayoutChildType

Get the relative row offset of the child at the given index, returning None for any auxiliary children, e.g. dictionary values, zone maps, etc.

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fn metadata(&self) -> Vec<u8> ⓘ

Serialize this layout’s encoding metadata.

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fn segment_ids(&self) -> Vec<SegmentId>

Get the segment IDs directly referenced by this layout node.

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

Construct a new reader for this layout.

name — human-readable label for this reader, propagated to child readers (typically by appending a path component) and surfaced in tracing/debug output.
segment_source — source of segment bytes for this and any descendant readers constructed from the returned reader; recursive callers should pass the same source through.
session — the VortexSession hosting the encoding/scalar/layout registries and execution context the reader needs at evaluation time.
ctx — id-keyed dependency registry threaded through reader construction (see LayoutReaderContext). Top-level callers (file open, tests) typically pass &LayoutReaderContext::new(); recursive callers inside layout implementations must propagate the ctx they were handed so ancestor-published values reach descendants.