SuKi2cn commented on code in PR #335: URL: https://github.com/apache/iceberg-cpp/pull/335#discussion_r2557004364
########## src/iceberg/expression/aggregate.cc: ########## @@ -0,0 +1,256 @@ +/* + * 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. + */ + +#include "iceberg/expression/aggregate.h" + +#include <format> +#include <optional> +#include <vector> + +#include "iceberg/exception.h" +#include "iceberg/expression/binder.h" +#include "iceberg/row/struct_like.h" +#include "iceberg/type.h" +#include "iceberg/util/checked_cast.h" +#include "iceberg/util/macros.h" + +namespace iceberg { + +namespace { + +Result<std::shared_ptr<PrimitiveType>> GetPrimitiveType(const BoundTerm& term) { + auto primitive = std::dynamic_pointer_cast<PrimitiveType>(term.type()); + if (primitive == nullptr) { + return InvalidExpression("Aggregate requires primitive type, got {}", + term.type()->ToString()); + } + return primitive; +} + +} // namespace + +// -------------------- Bound aggregates -------------------- + +BoundCountAggregate::BoundCountAggregate(Expression::Operation op, Mode mode, + std::shared_ptr<BoundTerm> term) + : BoundAggregate(op, std::move(term)), mode_(mode) {} + +std::string BoundCountAggregate::ToString() const { + if (mode_ == Mode::kStar) { + return "count(*)"; + } + ICEBERG_DCHECK(term() != nullptr, "Bound count aggregate should have term"); + switch (mode_) { + case Mode::kNull: + return std::format("count_null({})", term()->reference()->name()); + case Mode::kNonNull: + return std::format("count({})", term()->reference()->name()); + case Mode::kStar: + break; + } + std::unreachable(); +} + +Result<Literal> BoundCountAggregate::Evaluate(const StructLike& data) const { + switch (mode_) { + case Mode::kStar: + return Literal::Long(1); + case Mode::kNonNull: { + ICEBERG_ASSIGN_OR_RAISE(auto literal, term()->Evaluate(data)); + return Literal::Long(literal.IsNull() ? 0 : 1); + } + case Mode::kNull: { + ICEBERG_ASSIGN_OR_RAISE(auto literal, term()->Evaluate(data)); + return Literal::Long(literal.IsNull() ? 1 : 0); + } + } + std::unreachable(); +} + +BoundValueAggregate::BoundValueAggregate(Expression::Operation op, + std::shared_ptr<BoundTerm> term) + : BoundAggregate(op, std::move(term)) {} + +std::string BoundValueAggregate::ToString() const { + ICEBERG_DCHECK(term() != nullptr, "Bound value aggregate should have term"); + auto prefix = op() == Expression::Operation::kMax ? "max" : "min"; + return std::format("{}({})", prefix, term()->reference()->name()); +} + +Result<Literal> BoundValueAggregate::Evaluate(const StructLike& data) const { + ICEBERG_ASSIGN_OR_RAISE(auto literal, term()->Evaluate(data)); + return literal; +} + +// -------------------- Unbound binding -------------------- + +template <typename B> +Result<std::shared_ptr<Expression>> UnboundAggregateImpl<B>::Bind( + const Schema& schema, bool case_sensitive) const { + std::shared_ptr<B> bound_term; + if (this->term()) { + ICEBERG_ASSIGN_OR_THROW(bound_term, this->term()->Bind(schema, case_sensitive)); + } + + switch (count_mode_) { + case CountMode::kStar: + case CountMode::kNull: + case CountMode::kNonNull: { + auto op = this->op() == Expression::Operation::kCountStar + ? Expression::Operation::kCountStar + : Expression::Operation::kCount; + auto mode = + count_mode_ == CountMode::kNull + ? BoundCountAggregate::Mode::kNull + : (count_mode_ == CountMode::kStar ? BoundCountAggregate::Mode::kStar + : BoundCountAggregate::Mode::kNonNull); + auto aggregate = + std::make_shared<BoundCountAggregate>(op, mode, std::move(bound_term)); + return aggregate; + } + case CountMode::kNone: { + if (this->op() != Expression::Operation::kMax && + this->op() != Expression::Operation::kMin) { + return NotSupported("Unsupported aggregate operation"); + } + if (!bound_term) { + return InvalidExpression("Aggregate requires a term"); + } + auto aggregate = + std::make_shared<BoundValueAggregate>(this->op(), std::move(bound_term)); + return aggregate; + } + } + std::unreachable(); +} + +template class UnboundAggregateImpl<BoundReference>; + +// -------------------- AggregateEvaluator -------------------- + +namespace { + +class AggregateEvaluatorImpl : public AggregateEvaluator { Review Comment: Thanks, that’s a good point. -- This is an automated message from the Apache Git Service. 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