bkietz commented on a change in pull request #8894: URL: https://github.com/apache/arrow/pull/8894#discussion_r545384788
########## File path: cpp/src/arrow/dataset/expression_internal.h ########## @@ -0,0 +1,465 @@ +// 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 "arrow/dataset/expression.h" + +#include <unordered_map> +#include <unordered_set> +#include <vector> + +#include "arrow/compute/api_vector.h" +#include "arrow/compute/registry.h" +#include "arrow/record_batch.h" +#include "arrow/table.h" +#include "arrow/util/logging.h" + +namespace arrow { + +using internal::checked_cast; + +namespace dataset { + +bool Identical(const Expression& l, const Expression& r) { return l.impl_ == r.impl_; } + +const Expression::Call* CallNotNull(const Expression& expr) { + auto call = expr.call(); + DCHECK_NE(call, nullptr); + return call; +} + +inline void GetAllFieldRefs(const Expression& expr, + std::unordered_set<FieldRef, FieldRef::Hash>* refs) { + if (auto lit = expr.literal()) return; + + if (auto ref = expr.field_ref()) { + refs->emplace(*ref); + return; + } + + for (const Expression& arg : CallNotNull(expr)->arguments) { + GetAllFieldRefs(arg, refs); + } +} + +inline std::vector<ValueDescr> GetDescriptors(const std::vector<Expression>& exprs) { + std::vector<ValueDescr> descrs(exprs.size()); + for (size_t i = 0; i < exprs.size(); ++i) { + DCHECK(exprs[i].IsBound()); + descrs[i] = exprs[i].descr(); + } + return descrs; +} + +inline std::vector<ValueDescr> GetDescriptors(const std::vector<Datum>& values) { + std::vector<ValueDescr> descrs(values.size()); + for (size_t i = 0; i < values.size(); ++i) { + descrs[i] = values[i].descr(); + } + return descrs; +} + +struct FieldPathGetDatumImpl { + template <typename T, typename = decltype(FieldPath{}.Get(std::declval<const T&>()))> + Result<Datum> operator()(const std::shared_ptr<T>& ptr) { + return path_.Get(*ptr).template As<Datum>(); + } + + template <typename T> + Result<Datum> operator()(const T&) { + return Status::NotImplemented("FieldPath::Get() into Datum ", datum_.ToString()); + } + + const Datum& datum_; + const FieldPath& path_; +}; + +inline Result<Datum> GetDatumField(const FieldRef& ref, const Datum& input) { + Datum field; + + FieldPath path; + if (auto type = input.type()) { + ARROW_ASSIGN_OR_RAISE(path, ref.FindOneOrNone(*input.type())); + } else if (input.kind() == Datum::RECORD_BATCH) { + ARROW_ASSIGN_OR_RAISE(path, ref.FindOneOrNone(*input.record_batch()->schema())); + } else if (input.kind() == Datum::TABLE) { + ARROW_ASSIGN_OR_RAISE(path, ref.FindOneOrNone(*input.table()->schema())); + } + + if (path) { + ARROW_ASSIGN_OR_RAISE(field, + util::visit(FieldPathGetDatumImpl{input, path}, input.value)); + } + + if (field == Datum{}) { + field = Datum(std::make_shared<NullScalar>()); + } + + return field; +} + +struct Comparison { + enum type { + NA = 0, + EQUAL = 1, + LESS = 2, + GREATER = 4, + NOT_EQUAL = LESS | GREATER, + LESS_EQUAL = LESS | EQUAL, + GREATER_EQUAL = GREATER | EQUAL, + }; + + static const type* Get(const std::string& function) { + static std::unordered_map<std::string, type> flipped_comparisons{ + {"equal", EQUAL}, {"not_equal", NOT_EQUAL}, + {"less", LESS}, {"less_equal", LESS_EQUAL}, + {"greater", GREATER}, {"greater_equal", GREATER_EQUAL}, + }; + + auto it = flipped_comparisons.find(function); + return it != flipped_comparisons.end() ? &it->second : nullptr; + } + + static const type* Get(const Expression& expr) { + if (auto call = expr.call()) { + return Comparison::Get(call->function_name); + } + return nullptr; + } + + // Execute a simple Comparison between scalars, casting the RHS if types disagree + static Result<type> Execute(Datum l, Datum r) { + if (!l.is_scalar() || !r.is_scalar()) { + return Status::Invalid("Cannot Execute Comparison on non-scalars"); + } + + if (!l.type()->Equals(r.type())) { + ARROW_ASSIGN_OR_RAISE(r, compute::Cast(r, l.type())); + } + + std::vector<Datum> arguments{std::move(l), std::move(r)}; + + ARROW_ASSIGN_OR_RAISE(auto equal, compute::CallFunction("equal", arguments)); + + if (!equal.scalar()->is_valid) return NA; + if (equal.scalar_as<BooleanScalar>().value) return EQUAL; + + ARROW_ASSIGN_OR_RAISE(auto less, compute::CallFunction("less", arguments)); + + if (!less.scalar()->is_valid) return NA; + return less.scalar_as<BooleanScalar>().value ? LESS : GREATER; + } + + static type GetFlipped(type op) { + switch (op) { + case NA: + return NA; + case EQUAL: + return EQUAL; + case LESS: + return GREATER; + case GREATER: + return LESS; + case NOT_EQUAL: + return NOT_EQUAL; + case LESS_EQUAL: + return GREATER_EQUAL; + case GREATER_EQUAL: + return LESS_EQUAL; + } + DCHECK(false); + return NA; + } + + static std::string GetName(type op) { + switch (op) { + case NA: + DCHECK(false) << "unreachable"; + break; + case EQUAL: + return "equal"; + case LESS: + return "less"; + case GREATER: + return "greater"; + case NOT_EQUAL: + return "not_equal"; + case LESS_EQUAL: + return "less_equal"; + case GREATER_EQUAL: + return "greater_equal"; + } + DCHECK(false); + return "na"; + } + + static std::string GetOp(type op) { + switch (op) { + case NA: + DCHECK(false) << "unreachable"; + break; + case EQUAL: + return "=="; + case LESS: + return "<"; + case GREATER: + return ">"; + case NOT_EQUAL: + return "!="; + case LESS_EQUAL: + return "<="; + case GREATER_EQUAL: + return ">="; + } + DCHECK(false); + return ""; + } +}; + +inline const compute::CastOptions* GetCastOptions(const Expression::Call& call) { + if (call.function_name != "cast") return nullptr; + return checked_cast<const compute::CastOptions*>(call.options.get()); +} + +inline bool IsSetLookup(const std::string& function) { + return function == "is_in" || function == "index_in"; +} + +inline bool IsSameTypesBinary(const std::string& function) { + if (Comparison::Get(function)) return true; + + static std::unordered_set<std::string> set{"add", "subtract", "multiply", "divide"}; + + return set.find(function) != set.end(); +} + +inline const compute::SetLookupOptions* GetSetLookupOptions( + const Expression::Call& call) { + if (!IsSetLookup(call.function_name)) return nullptr; + return checked_cast<const compute::SetLookupOptions*>(call.options.get()); +} + +inline const compute::StructOptions* GetStructOptions(const Expression::Call& call) { + if (call.function_name != "struct") return nullptr; + return checked_cast<const compute::StructOptions*>(call.options.get()); +} + +inline const compute::StrptimeOptions* GetStrptimeOptions(const Expression::Call& call) { + if (call.function_name != "strptime") return nullptr; + return checked_cast<const compute::StrptimeOptions*>(call.options.get()); +} + +inline const std::shared_ptr<DataType>& GetDictionaryValueType( + const std::shared_ptr<DataType>& type) { + if (type && type->id() == Type::DICTIONARY) { + return checked_cast<const DictionaryType&>(*type).value_type(); + } + static std::shared_ptr<DataType> null; + return null; +} + +inline Status EnsureNotDictionary(ValueDescr* descr) { + if (auto value_type = GetDictionaryValueType(descr->type)) { + descr->type = std::move(value_type); + } + return Status::OK(); +} + +inline Status EnsureNotDictionary(Datum* datum) { + if (datum->type()->id() == Type::DICTIONARY) { + const auto& type = checked_cast<const DictionaryType&>(*datum->type()).value_type(); + ARROW_ASSIGN_OR_RAISE(*datum, compute::Cast(*datum, type)); + } + return Status::OK(); +} + +inline Status EnsureNotDictionary(Expression::Call* call) { + if (auto options = GetSetLookupOptions(*call)) { + auto new_options = *options; + RETURN_NOT_OK(EnsureNotDictionary(&new_options.value_set)); + call->options.reset(new compute::SetLookupOptions(std::move(new_options))); + } + return Status::OK(); +} + +inline Result<std::shared_ptr<StructScalar>> FunctionOptionsToStructScalar( + const Expression::Call& call) { + if (call.options == nullptr) { + return nullptr; + } + + auto Finish = [](ScalarVector values, std::vector<std::string> names) { Review comment: Alright, I'll add a constructor ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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