mod.rs

// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: Copyright the Vortex contributors

use std::hash::Hasher;

use kernel::PARENT_KERNELS;
use vortex_error::VortexExpect;
use vortex_error::VortexResult;
use vortex_error::vortex_bail;
use vortex_error::vortex_ensure;
use vortex_error::vortex_panic;
use vortex_session::VortexSession;
use vortex_session::registry::CachedId;

use crate::ArrayEq;
use crate::ArrayHash;
use crate::ArrayRef;
use crate::ExecutionCtx;
use crate::ExecutionResult;
use crate::Precision;
use crate::array::Array;
use crate::array::ArrayId;
use crate::array::ArrayView;
use crate::array::VTable;
use crate::array::ValidityVTableFromChild;
use crate::arrays::extension::ExtensionData;
use crate::arrays::extension::array::SLOT_NAMES;
use crate::arrays::extension::array::STORAGE_SLOT;
use crate::arrays::extension::compute::rules::PARENT_RULES;
use crate::arrays::extension::compute::rules::RULES;
use crate::buffer::BufferHandle;
use crate::dtype::DType;
use crate::serde::ArrayChildren;

mod kernel;
mod operations;
mod validity;

#[derive(Clone, Debug)]
pub struct Extension;

/// A [`Extension`]-encoded Vortex array.
pub type ExtensionArray = Array<Extension>;

impl ArrayHash for ExtensionData {
    fn array_hash<H: Hasher>(&self, _state: &mut H, _precision: Precision) {}
}

impl ArrayEq for ExtensionData {
    fn array_eq(&self, _other: &Self, _precision: Precision) -> bool {
        true
    }
}

impl VTable for Extension {
    type ArrayData = ExtensionData;

    type OperationsVTable = Self;
    type ValidityVTable = ValidityVTableFromChild;

    fn id(&self) -> ArrayId {
        static ID: CachedId = CachedId::new("vortex.ext");
        *ID
    }

    fn validate(
        &self,
        data: &ExtensionData,
        dtype: &DType,
        len: usize,
        slots: &[Option<ArrayRef>],
    ) -> VortexResult<()> {
        _ = data;
        let storage = slots[STORAGE_SLOT]
            .as_ref()
            .vortex_expect("ExtensionArray storage slot");
        vortex_ensure!(
            storage.len() == len,
            "ExtensionArray length {} does not match outer length {}",
            storage.len(),
            len
        );

        let actual_dtype = DType::Extension(data.ext_dtype.clone());
        vortex_ensure!(
            &actual_dtype == dtype,
            "ExtensionArray dtype {} does not match outer dtype {}",
            actual_dtype,
            dtype
        );

        Ok(())
    }

    fn nbuffers(_array: ArrayView<'_, Self>) -> usize {
        0
    }

    fn buffer(_array: ArrayView<'_, Self>, idx: usize) -> BufferHandle {
        vortex_panic!("ExtensionArray buffer index {idx} out of bounds")
    }

    fn buffer_name(_array: ArrayView<'_, Self>, _idx: usize) -> Option<String> {
        None
    }

    fn serialize(
        _array: ArrayView<'_, Self>,
        _session: &VortexSession,
    ) -> VortexResult<Option<Vec<u8>>> {
        Ok(Some(vec![]))
    }

    fn deserialize(
        &self,
        dtype: &DType,
        len: usize,
        metadata: &[u8],

        _buffers: &[BufferHandle],
        children: &dyn ArrayChildren,
        _session: &VortexSession,
    ) -> VortexResult<crate::array::ArrayParts<Self>> {
        if !metadata.is_empty() {
            vortex_bail!(
                "ExtensionArray expects empty metadata, got {} bytes",
                metadata.len()
            );
        }
        let DType::Extension(ext_dtype) = dtype else {
            vortex_bail!("Not an extension DType");
        };
        if children.len() != 1 {
            vortex_bail!("Expected 1 child, got {}", children.len());
        }
        let storage = children.get(0, ext_dtype.storage_dtype(), len)?;
        Ok(crate::array::ArrayParts::new(
            self.clone(),
            dtype.clone(),
            len,
            ExtensionData::new(ext_dtype.clone(), storage.dtype()),
        )
        .with_slots(vec![Some(storage)]))
    }

    fn slot_name(_array: ArrayView<'_, Self>, idx: usize) -> String {
        SLOT_NAMES[idx].to_string()
    }

    fn execute(array: Array<Self>, _ctx: &mut ExecutionCtx) -> VortexResult<ExecutionResult> {
        Ok(ExecutionResult::done(array))
    }

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

    fn reduce(array: ArrayView<'_, Self>) -> VortexResult<Option<ArrayRef>> {
        RULES.evaluate(array)
    }

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