marvinlanhenke commented on code in PR #363: URL: https://github.com/apache/iceberg-rust/pull/363#discussion_r1612174468
########## crates/iceberg/src/expr/visitors/expression_evaluator.rs: ########## @@ -0,0 +1,819 @@ +// 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 fnv::FnvHashSet; + +use crate::{ + expr::{BoundPredicate, BoundReference}, + spec::{DataFile, Datum, PrimitiveLiteral, Struct}, + Error, ErrorKind, Result, +}; + +use super::bound_predicate_visitor::{visit, BoundPredicateVisitor}; + +/// Evaluates a [`DataFile`]'s partition [`Struct`] to check +/// if the partition tuples match the given [`BoundPredicate`]. +/// +/// Use within [`TableScan`] to prune the list of [`DataFile`]s +/// that could potentially match the TableScan's filter. +#[derive(Debug)] +pub(crate) struct ExpressionEvaluator { + /// The provided partition filter. + partition_filter: BoundPredicate, +} + +impl ExpressionEvaluator { + /// Creates a new [`ExpressionEvaluator`]. + pub(crate) fn new(partition_filter: BoundPredicate) -> Self { + Self { partition_filter } + } + + /// Evaluate this [`ExpressionEvaluator`]'s partition filter against + /// the provided [`DataFile`]'s partition [`Struct`]. Used by [`TableScan`] + /// to see if this [`DataFile`] could possibly contain data that matches + /// the scan's filter. + pub(crate) fn eval(&self, data_file: &DataFile) -> Result<bool> { + let mut visitor = ExpressionEvaluatorVisitor::new(self, data_file.partition()); + + visit(&mut visitor, &self.partition_filter) + } +} + +/// Acts as a visitor for [`ExpressionEvaluator`] to apply +/// evaluation logic to different parts of a data structure, +/// specifically for data file partitions. +#[derive(Debug)] +struct ExpressionEvaluatorVisitor<'a> { + /// Reference to an [`ExpressionEvaluator`]. + expression_evaluator: &'a ExpressionEvaluator, + /// Reference to a [`DataFile`]'s partition [`Struct`]. + partition: &'a Struct, +} + +impl<'a> ExpressionEvaluatorVisitor<'a> { + /// Creates a new [`ExpressionEvaluatorVisitor`]. + fn new(expression_evaluator: &'a ExpressionEvaluator, partition: &'a Struct) -> Self { + Self { + expression_evaluator, + partition, + } + } + + /// Checks if the [`PrimitiveLiteral`] is null. + fn is_null(literal: &PrimitiveLiteral) -> bool { + if let PrimitiveLiteral::Boolean(false) = literal { Review Comment: > Otherwise how do you distinguish it from actual value of `PrimitiveLiteral::Boolean(false)`. And the `Accessor` should return `Option<Literal>`. Yeah, this makes sense to me. Regarding the `Accessor` will you open another issue or @sdd something you might want to take a look at? Since I'm not to familiar with the `Accessor` and to verify my understanding; in order to return Option<Literal> here we should check the `null_bitmap` of the `Struct` at the position and if the null_bitmap is true we can return `None` from the `Accessor`? -- 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: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
