query_optimizer/expressions/AttributeReference.cpp

/**
 * 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 "query_optimizer/expressions/AttributeReference.hpp"

#include <cstddef>
#include <functional>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#include "expressions/scalar/Scalar.hpp"
#include "expressions/scalar/ScalarAttribute.hpp"
#include "query_optimizer/expressions/ExprId.hpp"
#include "query_optimizer/expressions/Expression.hpp"
#include "query_optimizer/expressions/PatternMatcher.hpp"

#include "glog/logging.h"

namespace quickstep {
namespace optimizer {
namespace expressions {

ExpressionPtr AttributeReference::copyWithNewChildren(
    const std::vector<ExpressionPtr> &new_children) const {
  DCHECK_EQ(new_children.size(), children().size());
  return AttributeReference::Create(id(),
                                    attribute_name(),
                                    attribute_alias(),
                                    relation_name(),
                                    getValueType(),
                                    scope());
}

std::vector<AttributeReferencePtr> AttributeReference::getReferencedAttributes()
    const {
  return { Create(id(), attribute_name(), attribute_alias(), relation_name(), getValueType(), scope()) };
}

::quickstep::Scalar *AttributeReference::concretize(
    const std::unordered_map<ExprId, const CatalogAttribute*> &substitution_map,
    const std::unordered_set<ExprId> &left_expr_ids,
    const std::unordered_set<ExprId> &right_expr_ids) const {
  const ExprId expr_id = id();
  const std::unordered_map<ExprId, const CatalogAttribute*>::const_iterator found_it =
      substitution_map.find(expr_id);
  DCHECK(found_it != substitution_map.end()) << toString();

  ::quickstep::Scalar::JoinSide join_side = ::quickstep::Scalar::kNone;
  if (left_expr_ids.find(expr_id) != left_expr_ids.end()) {
    join_side = ::quickstep::Scalar::kLeftSide;
  } else if (right_expr_ids.find(expr_id) != right_expr_ids.end()) {
    join_side = ::quickstep::Scalar::kRightSide;
  }

  return new ::quickstep::ScalarAttribute(*found_it->second, join_side);
}

std::size_t AttributeReference::computeHash() const {
  return std::hash<std::size_t>()(static_cast<std::size_t>(id()));
}

bool AttributeReference::equals(const ScalarPtr &other) const {
  AttributeReferencePtr attr;
  if (SomeAttributeReference::MatchesWithConditionalCast(other, &attr)) {
    if (id() != attr->id()) {
      return false;
    }
    DCHECK(type_.equals(attr->type_));
    return true;
  }
  return false;
}

void AttributeReference::getFieldStringItems(
    std::vector<std::string> *inline_field_names,
    std::vector<std::string> *inline_field_values,
    std::vector<std::string> *non_container_child_field_names,
    std::vector<OptimizerTreeBaseNodePtr> *non_container_child_fields,
    std::vector<std::string> *container_child_field_names,
    std::vector<std::vector<OptimizerTreeBaseNodePtr>> *container_child_fields) const {
  NamedExpression::getFieldStringItems(
      inline_field_names,
      inline_field_values,
      non_container_child_field_names,
      non_container_child_fields,
      container_child_field_names,
      container_child_fields);

  if (scope_ == AttributeReferenceScope::kOuter) {
    inline_field_names->push_back("is_outer_reference");
    inline_field_values->push_back("true");
  }
}

}  // namespace expressions
}  // namespace optimizer
}  // namespace quickstep