friendlymatthew commented on code in PR #7905: URL: https://github.com/apache/arrow-rs/pull/7905#discussion_r2201092686
########## parquet-variant-compute/src/variant_array.rs: ########## @@ -0,0 +1,227 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! [`VariantArray`] implementation + +use arrow::array::{Array, ArrayData, ArrayRef, AsArray, StructArray}; +use arrow::buffer::NullBuffer; +use arrow_schema::{ArrowError, DataType}; +use parquet_variant::Variant; +use std::any::Any; +use std::sync::Arc; + +/// An array of Parquet [`Variant`] values +/// +/// A [`VariantArray`] wraps an Arrow [`StructArray`] that stores the underlying +/// `metadata` and `value` fields, and adds convenience methods to access +/// the `Variant`s +/// +/// See [`VariantArrayBuilder`] for constructing a `VariantArray`. +/// +/// [`VariantArrayBuilder`]: crate::VariantArrayBuilder +/// +/// # Specification +/// 1. This code follows the conventions for storing variants in Arrow Struct Array +/// defined by [Extension Type for Parquet Variant arrow] and this [document]. +/// At the time of this writing, this is not yet a standardized Arrow extension type. +/// +/// [Extension Type for Parquet Variant arrow]: https://github.com/apache/arrow/issues/46908 +/// [document]: https://docs.google.com/document/d/1pw0AWoMQY3SjD7R4LgbPvMjG_xSCtXp3rZHkVp9jpZ4/edit?usp=sharing +#[derive(Debug)] +pub struct VariantArray { + /// StructArray or up to three fields: + /// 1. A required field named metadata which is binary, large_binary, or binary_view + /// 2. An optional field named value that is binary, large_binary, or binary_view + /// 3. An optional field named typed_value which can be any primitive type or be a list, large_list, list_view or struct + /// + /// If typed_value is a nested type, its elements must be required and must + /// be a struct containing only one of the following: + /// + /// 1. A single required field, of type binary, large_binary, or binary_view named value + /// + /// 2. An optional field named value of type binary, large_binary, or + /// binary_view AND an optional field named typed_value which follows these + /// same rules + /// + /// NOTE: It is also permissible for the metadata field to be + /// Dictionary-Encoded, preferably (but not required) with an index type of + /// int8. + inner: StructArray, +} + +impl VariantArray { + /// Creates a new `VariantArray` from a [`StructArray`]. + /// + /// # Arguments + /// - `inner` - The underlying [`StructArray`] that contains the variant data. + /// + /// # Returns + /// - A new instance of `VariantArray`. + /// + /// # Errors: + /// If the `StructArray` does not contain the required fields + pub fn try_new(inner: ArrayRef) -> Result<Self, ArrowError> { + let Some(inner) = inner.as_struct_opt() else { + return Err(ArrowError::InvalidArgumentError( + "Invalid VariantArray: requires StructArray as input".to_string(), + )); + }; + // Ensure the StructArray has the expected fields + if !inner.fields().iter().any(|f| f.name() == "metadata") { + return Err(ArrowError::InvalidArgumentError( + "Invalid VariantArray: StructArray must contain a 'metadata' field".to_string(), + )); + } + if !inner.fields().iter().any(|f| f.name() == "value") { + return Err(ArrowError::InvalidArgumentError( + "Invalid VariantArray: StructArray must contain a 'value' field".to_string(), + )); + } Review Comment: More of a note to myself for the shredding work, but I don't think we should necessarily error when the `value` column is not found. ########## parquet-variant-compute/src/variant_array.rs: ########## @@ -0,0 +1,227 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! [`VariantArray`] implementation + +use arrow::array::{Array, ArrayData, ArrayRef, AsArray, StructArray}; +use arrow::buffer::NullBuffer; +use arrow_schema::{ArrowError, DataType}; +use parquet_variant::Variant; +use std::any::Any; +use std::sync::Arc; + +/// An array of Parquet [`Variant`] values +/// +/// A [`VariantArray`] wraps an Arrow [`StructArray`] that stores the underlying +/// `metadata` and `value` fields, and adds convenience methods to access +/// the `Variant`s +/// +/// See [`VariantArrayBuilder`] for constructing a `VariantArray`. +/// +/// [`VariantArrayBuilder`]: crate::VariantArrayBuilder +/// +/// # Specification +/// 1. This code follows the conventions for storing variants in Arrow Struct Array +/// defined by [Extension Type for Parquet Variant arrow] and this [document]. +/// At the time of this writing, this is not yet a standardized Arrow extension type. +/// +/// [Extension Type for Parquet Variant arrow]: https://github.com/apache/arrow/issues/46908 +/// [document]: https://docs.google.com/document/d/1pw0AWoMQY3SjD7R4LgbPvMjG_xSCtXp3rZHkVp9jpZ4/edit?usp=sharing +#[derive(Debug)] +pub struct VariantArray { + /// StructArray or up to three fields: + /// 1. A required field named metadata which is binary, large_binary, or binary_view + /// 2. An optional field named value that is binary, large_binary, or binary_view + /// 3. An optional field named typed_value which can be any primitive type or be a list, large_list, list_view or struct + /// + /// If typed_value is a nested type, its elements must be required and must + /// be a struct containing only one of the following: + /// + /// 1. A single required field, of type binary, large_binary, or binary_view named value + /// + /// 2. An optional field named value of type binary, large_binary, or + /// binary_view AND an optional field named typed_value which follows these + /// same rules + /// + /// NOTE: It is also permissible for the metadata field to be + /// Dictionary-Encoded, preferably (but not required) with an index type of + /// int8. + inner: StructArray, +} + +impl VariantArray { + /// Creates a new `VariantArray` from a [`StructArray`]. + /// + /// # Arguments + /// - `inner` - The underlying [`StructArray`] that contains the variant data. + /// + /// # Returns + /// - A new instance of `VariantArray`. + /// + /// # Errors: + /// If the `StructArray` does not contain the required fields + pub fn try_new(inner: ArrayRef) -> Result<Self, ArrowError> { + let Some(inner) = inner.as_struct_opt() else { + return Err(ArrowError::InvalidArgumentError( + "Invalid VariantArray: requires StructArray as input".to_string(), + )); + }; + // Ensure the StructArray has the expected fields + if !inner.fields().iter().any(|f| f.name() == "metadata") { + return Err(ArrowError::InvalidArgumentError( + "Invalid VariantArray: StructArray must contain a 'metadata' field".to_string(), + )); + } + if !inner.fields().iter().any(|f| f.name() == "value") { + return Err(ArrowError::InvalidArgumentError( + "Invalid VariantArray: StructArray must contain a 'value' field".to_string(), + )); + } Review Comment: More of a note to myself for the shredding work, but I don't think we should necessarily error when the `value` column is not found? -- This is an automated message from the Apache Git Service. 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