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VTable

Trait VTable 

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pub trait VTable:
    'static
    + Clone
    + Sized
    + Send
    + Sync
    + Debug {
    type ArrayData: 'static + Send + Sync + Clone + Debug + Display + ArrayHash + ArrayEq;
    type OperationsVTable: OperationsVTable<Self>;
    type ValidityVTable: ValidityVTable<Self>;

Show 16 methods // Required methods fn id(&self) -> ArrayId; fn validate( &self, data: &Self::ArrayData, dtype: &DType, len: usize, slots: &[Option<ArrayRef>], ) -> VortexResult<()>; fn nbuffers(array: ArrayView<'_, Self>) -> usize; fn buffer(array: ArrayView<'_, Self>, idx: usize) -> BufferHandle; fn buffer_name(array: ArrayView<'_, Self>, idx: usize) -> Option<String>; fn serialize( array: ArrayView<'_, Self>, session: &VortexSession, ) -> VortexResult<Option<Vec<u8>>>; fn deserialize( &self, dtype: &DType, len: usize, metadata: &[u8], buffers: &[BufferHandle], children: &dyn ArrayChildren, session: &VortexSession, ) -> VortexResult<ArrayParts<Self>>; fn slot_name(array: ArrayView<'_, Self>, idx: usize) -> String; fn execute( array: Array<Self>, ctx: &mut ExecutionCtx, ) -> VortexResult<ExecutionResult>; // Provided methods fn nchildren(array: ArrayView<'_, Self>) -> usize { ... } fn child(array: ArrayView<'_, Self>, idx: usize) -> ArrayRef { ... } fn child_name(array: ArrayView<'_, Self>, idx: usize) -> String { ... } fn append_to_builder( array: ArrayView<'_, Self>, builder: &mut dyn ArrayBuilder, ctx: &mut ExecutionCtx, ) -> VortexResult<()> { ... } fn execute_parent( array: ArrayView<'_, Self>, parent: &ArrayRef, child_idx: usize, ctx: &mut ExecutionCtx, ) -> VortexResult<Option<ArrayRef>> { ... } fn reduce(array: ArrayView<'_, Self>) -> VortexResult<Option<ArrayRef>> { ... } fn reduce_parent( array: ArrayView<'_, Self>, parent: &ArrayRef, child_idx: usize, ) -> VortexResult<Option<ArrayRef>> { ... }
}
Expand description

The array VTable encapsulates logic for an Array type within Vortex.

The logic is split across several “VTable” traits to enable easier code organization than simply lumping everything into a single trait.

From this VTable trait, we derive implementations for the sealed DynArray trait and the public ArrayPlugin registry trait.

The functions defined in these vtable traits will typically document their pre- and post-conditions. The pre-conditions are validated inside the DynArray and ArrayRef implementations so do not need to be checked in the vtable implementations (for example, index out of bounds). Post-conditions are validated after invocation of the vtable function and will panic if violated.

Required Associated Types§

Required Methods§

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fn id(&self) -> ArrayId

Returns the ID of the array.

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fn validate( &self, data: &Self::ArrayData, dtype: &DType, len: usize, slots: &[Option<ArrayRef>], ) -> VortexResult<()>

Validates that externally supplied logical metadata matches the array data.

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fn nbuffers(array: ArrayView<'_, Self>) -> usize

Returns the number of buffers in the array.

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fn buffer(array: ArrayView<'_, Self>, idx: usize) -> BufferHandle

Returns the buffer at the given index.

§Panics

Panics if idx >= nbuffers(array).

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fn buffer_name(array: ArrayView<'_, Self>, idx: usize) -> Option<String>

Returns the name of the buffer at the given index, or None if unnamed.

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fn serialize( array: ArrayView<'_, Self>, session: &VortexSession, ) -> VortexResult<Option<Vec<u8>>>

Serialize metadata into a byte buffer for IPC or file storage. Return None if the array cannot be serialized.

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fn deserialize( &self, dtype: &DType, len: usize, metadata: &[u8], buffers: &[BufferHandle], children: &dyn ArrayChildren, session: &VortexSession, ) -> VortexResult<ArrayParts<Self>>

Deserialize an array from serialized components.

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fn slot_name(array: ArrayView<'_, Self>, idx: usize) -> String

Returns the name of the slot at the given index.

§Panics

Panics if idx >= slots(array).len().

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fn execute( array: Array<Self>, ctx: &mut ExecutionCtx, ) -> VortexResult<ExecutionResult>

Execute this array by returning an ExecutionResult.

Execution is iterative, not recursive. Instead of recursively executing children, implementations should return ExecutionResult::execute_slot to request that the scheduler execute a slot first, or ExecutionResult::done when the encoding can produce a result directly.

For good examples of this pattern, see:

  • Dict::execute — demonstrates requiring children via require_child! and producing a result once they are canonical.
  • BitPacked::execute (in vortex-fastlanes) — demonstrates requiring patches and validity via require_patches!/require_validity!.

Array execution is designed such that repeated execution of an array will eventually converge to a canonical representation. Implementations of this function should therefore ensure they make progress towards that goal.

The returned array (in Done) must be logically equivalent to the input array. In other words, the recursively canonicalized forms of both arrays must be equal.

Debug builds will panic if the returned array is of the wrong type, wrong length, or incorrectly contains null values.

Provided Methods§

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fn nchildren(array: ArrayView<'_, Self>) -> usize

Returns the number of children in the array.

The default counts non-None slots.

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fn child(array: ArrayView<'_, Self>, idx: usize) -> ArrayRef

Returns the child at the given index.

The default returns the idx-th non-None slot.

§Panics

Panics if idx >= nchildren(array).

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fn child_name(array: ArrayView<'_, Self>, idx: usize) -> String

Returns the name of the child at the given index.

The default returns the slot name of the idx-th non-None slot.

§Panics

Panics if idx >= nchildren(array).

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fn append_to_builder( array: ArrayView<'_, Self>, builder: &mut dyn ArrayBuilder, ctx: &mut ExecutionCtx, ) -> VortexResult<()>

Writes the array into a canonical builder.

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fn execute_parent( array: ArrayView<'_, Self>, parent: &ArrayRef, child_idx: usize, ctx: &mut ExecutionCtx, ) -> VortexResult<Option<ArrayRef>>

Attempt to execute the parent of this array.

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fn reduce(array: ArrayView<'_, Self>) -> VortexResult<Option<ArrayRef>>

Attempt to reduce the array to a simpler representation.

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fn reduce_parent( array: ArrayView<'_, Self>, parent: &ArrayRef, child_idx: usize, ) -> VortexResult<Option<ArrayRef>>

Attempt to perform a reduction of the parent of this array.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

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impl VTable for Bool

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impl VTable for Chunked

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impl VTable for Constant

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impl VTable for Decimal

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impl VTable for Dict

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impl VTable for Extension

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impl VTable for Filter

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impl VTable for FixedSizeList

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impl VTable for List

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impl VTable for ListView

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impl VTable for Masked

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impl VTable for Null

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impl VTable for Patched

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impl VTable for Primitive

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impl VTable for ScalarFnVTable

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impl VTable for Shared

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impl VTable for Slice

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impl VTable for Struct

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impl VTable for VarBin

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impl VTable for VarBinView

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impl VTable for Variant