SparkApplicationMaster commented on code in PR #17456: URL: https://github.com/apache/datafusion/pull/17456#discussion_r2328808131
########## datafusion/spark/src/function/map/map_from_arrays.rs: ########## @@ -0,0 +1,207 @@ +// 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. + +use std::any::Any; +use std::borrow::Cow; +use std::collections::HashSet; +use std::sync::Arc; + +use arrow::array::{Array, ArrayRef, AsArray, BooleanBuilder, MapArray, StructArray}; +use arrow::buffer::OffsetBuffer; +use arrow::compute::filter; +use arrow::datatypes::{DataType, Field, Fields}; +use datafusion_common::utils::take_function_args; +use datafusion_common::{exec_err, internal_err, Result, ScalarValue}; +use datafusion_expr::{ColumnarValue, ScalarUDFImpl, Signature, Volatility}; +use datafusion_functions::utils::make_scalar_function; + +#[derive(Debug, PartialEq, Eq, Hash)] +pub struct MapFromArrays { + signature: Signature, +} + +impl Default for MapFromArrays { + fn default() -> Self { + Self::new() + } +} + +impl MapFromArrays { + pub fn new() -> Self { + Self { + signature: Signature::any(2, Volatility::Immutable), + } + } +} + +impl ScalarUDFImpl for MapFromArrays { + fn as_any(&self) -> &dyn Any { + self + } + + fn name(&self) -> &str { + "map_from_arrays" + } + + fn signature(&self) -> &Signature { + &self.signature + } + + fn return_type(&self, arg_types: &[DataType]) -> Result<DataType> { + let [key_type, value_type] = take_function_args("map_from_arrays", arg_types)?; + Ok(return_type_from_key_value_types( + get_element_type(key_type)?, + get_element_type(value_type)?, + )) + } + + fn invoke_with_args( + &self, + args: datafusion_expr::ScalarFunctionArgs, + ) -> Result<ColumnarValue> { + make_scalar_function(map_from_arrays_inner, vec![])(&args.args) + } +} + +fn get_list_field(data_type: &DataType) -> Result<&Arc<Field>> { + match data_type { + DataType::List(element) + | DataType::LargeList(element) + | DataType::FixedSizeList(element, _) => Ok(element), + _ => exec_err!( + "map_from_arrays expects 2 listarrays for keys and values as arguments, got {data_type:?}" + ), + } +} + +fn get_element_type(data_type: &DataType) -> Result<&DataType> { + get_list_field(data_type).map(|field| field.data_type()) +} + +pub fn return_type_from_key_value_types( + key_type: &DataType, + value_type: &DataType, +) -> DataType { + DataType::Map( + Arc::new(Field::new( + "entries", + DataType::Struct(Fields::from(vec![ + // the key must not be nullable + Field::new("key", key_type.clone(), false), + Field::new("value", value_type.clone(), true), + ])), + false, // the entry is not nullable + )), + false, // the keys are not sorted + ) +} + +fn get_list_values(array: &ArrayRef) -> Result<&ArrayRef> { + match array.data_type() { + DataType::List(_) => Ok(array.as_list::<i32>().values()), + DataType::LargeList(_) => Ok(array.as_list::<i64>().values()), + DataType::FixedSizeList(..) => Ok(array.as_fixed_size_list().values()), + wrong_type => internal_err!( + "get_list_values expects List/LargeList/FixedSizeList as argument, got {wrong_type:?}" + ), + } +} + +fn map_from_arrays_inner(args: &[ArrayRef]) -> Result<ArrayRef> { + let [keys, values] = take_function_args("map_from_arrays", args)?; + + let flat_keys = get_list_values(keys)?; + let flat_values = get_list_values(values)?; + + let offsets: Cow<[i32]> = match keys.data_type() { + DataType::List(_) => Ok(Cow::Borrowed(keys.as_list::<i32>().offsets().as_ref())), + DataType::LargeList(_) => Ok(Cow::Owned( + keys.as_list::<i64>() + .offsets() + .iter() + .map(|i| *i as i32) + .collect::<Vec<_>>(), + )), + DataType::FixedSizeList(_, size) => Ok(Cow::Owned( + (0..=keys.len() as i32).map(|i| size * i).collect() + )), + wrong_type => internal_err!( + "map_from_arrays expects List/LargeList/FixedSizeList as first argument, got {wrong_type:?}" + ), + }?; + + map_from_keys_values_offsets(flat_keys, flat_values, &offsets) +} + +pub fn map_from_keys_values_offsets( + keys: &ArrayRef, + values: &ArrayRef, + offsets: &[i32], +) -> Result<ArrayRef> { + let (keys, values, offsets) = map_deduplicate_keys(keys, values, offsets)?; + + let fields = Fields::from(vec![ + Field::new("key", keys.data_type().clone(), false), + Field::new("value", values.data_type().clone(), true), + ]); + let entries = StructArray::try_new(fields.clone(), vec![keys, values], None)?; + let field = Arc::new(Field::new("entries", DataType::Struct(fields), false)); + Ok(Arc::new(MapArray::try_new( + field, offsets, entries, None, false, + )?)) +} + +pub fn map_deduplicate_keys( + keys: &ArrayRef, + values: &ArrayRef, + offsets: &[i32], +) -> Result<(ArrayRef, ArrayRef, OffsetBuffer<i32>)> { + let num_rows = offsets.len() - 1; + let mut new_offsets = Vec::with_capacity(num_rows + 1); + new_offsets.push(0); + let mut last_offset = 0; + + let mut needed_rows_builder = BooleanBuilder::new(); + for row_num in 0..num_rows { + let cur_offset = offsets[row_num] as usize; + let next_offset = offsets[row_num + 1] as usize; Review Comment: sorry, this causes compile error, I suppose it cannot be guaranteed that size of this slice equals 2: ```rust let [cur_offset, next_offset] = offsets[row_num..=row_num + 1]; ``` ``` refutable pattern in local binding `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant for more information, visit https://doc.rust-lang.org/book/ch19-02-refutability.html the matched value is of type `[i32]`rustcClick for full compiler diagnostic map_from_arrays.rs(180, 71): you might want to use `let else` to handle the variants that aren't matched: ` else { todo!() }` ``` -- This is an automated message from the Apache Git Service. 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