mirror of https://gitee.com/bigwinds/arangodb
131 lines
4.6 KiB
C++
131 lines
4.6 KiB
C++
////////////////////////////////////////////////////////////////////////////////
|
|
/// DISCLAIMER
|
|
///
|
|
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
|
|
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
|
|
///
|
|
/// Licensed 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.
|
|
///
|
|
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
|
|
///
|
|
/// @author Jan Steemann
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#ifndef ARANGOD_AQL_SORT_CONDITION_H
|
|
#define ARANGOD_AQL_SORT_CONDITION_H 1
|
|
|
|
#include "Aql/Variable.h"
|
|
#include "Basics/AttributeNameParser.h"
|
|
#include "Basics/Common.h"
|
|
#include "Basics/HashSet.h"
|
|
|
|
namespace arangodb {
|
|
|
|
namespace aql {
|
|
struct AstNode;
|
|
class ExecutionPlan;
|
|
|
|
class SortCondition {
|
|
public:
|
|
SortCondition(SortCondition const&) = delete;
|
|
SortCondition& operator=(SortCondition const&) = delete;
|
|
|
|
/// @brief create an empty sort condition
|
|
SortCondition();
|
|
|
|
/// @brief create the sort condition
|
|
SortCondition(ExecutionPlan* plan,
|
|
std::vector<std::pair<Variable const*, bool>> const& variableDefinitions,
|
|
std::vector<std::vector<arangodb::basics::AttributeName>> const& constAttributes,
|
|
arangodb::HashSet<std::vector<arangodb::basics::AttributeName>> const& nonNullAttributes,
|
|
std::unordered_map<VariableId, AstNode const*> const& sorts);
|
|
|
|
/// @brief destroy the sort condition
|
|
~SortCondition();
|
|
|
|
public:
|
|
/// @brief whether or not the condition consists only of attribute accesses
|
|
inline bool isOnlyAttributeAccess() const { return _onlyAttributeAccess; }
|
|
|
|
/// @brief whether or not all conditions have the same sort order
|
|
inline bool isUnidirectional() const { return _unidirectional; }
|
|
|
|
/// @brief whether or not all sort directions are ascending
|
|
/// note that the return value of this function is only meaningful if the
|
|
/// sort is unidirectional
|
|
inline bool isAscending() const {
|
|
TRI_ASSERT(isUnidirectional());
|
|
return _ascending;
|
|
}
|
|
|
|
/// @brief whether or not all sort directions are descending
|
|
/// this is the reverse of isAscending()
|
|
inline bool isDescending() const { return !isAscending(); }
|
|
|
|
/// @brief whether or not there are fields
|
|
inline bool isEmpty() const { return _fields.empty(); }
|
|
|
|
/// @brief number of attributes in condition
|
|
inline size_t numAttributes() const { return _fields.size(); }
|
|
|
|
/// @brief returns the number of attributes in the sort condition covered
|
|
/// by the specified index fields
|
|
size_t coveredAttributes(Variable const*,
|
|
std::vector<std::vector<arangodb::basics::AttributeName>> const&) const;
|
|
|
|
/// @brief returns true if all attributes in the sort condition are proven
|
|
/// to be non-null
|
|
bool onlyUsesNonNullSortAttributes(
|
|
std::vector<std::vector<arangodb::basics::AttributeName>> const&) const;
|
|
|
|
/// @brief return the sort condition (as a tuple containing variable, AstNode
|
|
/// and sort order) at `position`.
|
|
/// `position` can be a value between 0 and the result of
|
|
/// SortCondition::numAttributes(). The bool attribute returned is whether
|
|
/// the sort order is ascending (true) or descending (false)
|
|
std::tuple<Variable const*, AstNode const*, bool> field(size_t position) const;
|
|
|
|
private:
|
|
struct SortField {
|
|
Variable const* variable;
|
|
std::vector<arangodb::basics::AttributeName> attributes;
|
|
AstNode const* node;
|
|
bool order;
|
|
};
|
|
|
|
ExecutionPlan* _plan;
|
|
|
|
/// @brief fields used in the sort conditions
|
|
std::vector<SortField> _fields;
|
|
|
|
/// @brief const attributes
|
|
std::vector<std::vector<arangodb::basics::AttributeName>> const _constAttributes;
|
|
|
|
/// @brief non-null attributes
|
|
arangodb::HashSet<std::vector<arangodb::basics::AttributeName>> const _nonNullAttributes;
|
|
|
|
/// @brief whether or not the sort is unidirectional
|
|
bool _unidirectional;
|
|
|
|
/// @brief whether the sort only consists of attribute accesses
|
|
bool _onlyAttributeAccess;
|
|
|
|
/// @brief whether or not all sorts are in ascending order.
|
|
/// this is only meaningful if the sort is unidirectional
|
|
bool _ascending;
|
|
};
|
|
} // namespace aql
|
|
} // namespace arangodb
|
|
|
|
#endif
|