comphead commented on code in PR #23852: URL: https://github.com/apache/datafusion/pull/23852#discussion_r3642213674
########## datafusion/spark/src/function/datetime/date_from_unix_date.rs: ########## @@ -0,0 +1,181 @@ +// 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::sync::Arc; + +use arrow::array::{Array, Date32Array, Int32Array}; +use arrow::datatypes::DataType; +use datafusion_common::utils::take_function_args; +use datafusion_common::{Result, ScalarValue, exec_err, internal_datafusion_err}; +use datafusion_expr::simplify::{ExprSimplifyResult, SimplifyContext}; +use datafusion_expr::{ + ColumnarValue, Expr, ExprSchemable, ScalarFunctionArgs, ScalarUDFImpl, Signature, + Volatility, +}; + +/// Spark-compatible `date_from_unix_date` function. +/// Creates a date from the number of days since epoch (1970-01-01). +/// <https://spark.apache.org/docs/latest/api/sql/index.html#date_from_unix_date> +#[derive(Debug, PartialEq, Eq, Hash)] +pub struct SparkDateFromUnixDate { + signature: Signature, +} + +impl Default for SparkDateFromUnixDate { + fn default() -> Self { + Self::new() + } +} + +impl SparkDateFromUnixDate { + pub fn new() -> Self { + Self { + signature: Signature::exact(vec![DataType::Int32], Volatility::Immutable), + } + } +} + +impl ScalarUDFImpl for SparkDateFromUnixDate { + fn name(&self) -> &str { + "date_from_unix_date" + } + + fn signature(&self) -> &Signature { + &self.signature + } + + fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> { + Ok(DataType::Date32) + } + + fn invoke_with_args(&self, args: ScalarFunctionArgs) -> Result<ColumnarValue> { + let [days] = take_function_args(self.name(), args.args)?; + match days { + ColumnarValue::Array(array) => { + let days = + array.as_any().downcast_ref::<Int32Array>().ok_or_else(|| { + internal_datafusion_err!( + "date_from_unix_date expected an Int32 array" + ) + })?; + // Date32 and Int32 both count days since the Unix epoch + // (1970-01-01), so the i32 values transfer directly. + let dates = + Date32Array::new(days.values().clone(), days.nulls().cloned()); + Ok(ColumnarValue::Array(Arc::new(dates))) + } + ColumnarValue::Scalar(ScalarValue::Int32(days)) => { + Ok(ColumnarValue::Scalar(ScalarValue::Date32(days))) + } + ColumnarValue::Scalar(other) => { + exec_err!("date_from_unix_date expected an Int32 argument, got {other:?}") + } + } + } + + fn simplify( + &self, + args: Vec<Expr>, + info: &SimplifyContext, + ) -> Result<ExprSimplifyResult> { + let [days] = take_function_args(self.name(), args)?; + Ok(ExprSimplifyResult::Simplified( + days.cast_to(&DataType::Date32, info.schema())?, + )) + } +} + +#[cfg(test)] +mod tests { Review Comment: the tests might be not needed as it should have already been covere by slt, however nice test would be to test `simplify` output and `invoke_with_args_output` are the same -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
