1
0
Fork 0
arangodb/arangod/Aql/IndexBlock.h

143 lines
4.3 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
/// @author Michael Hackstein
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_AQL_INDEX_BLOCK_H
#define ARANGOD_AQL_INDEX_BLOCK_H 1
#include "Aql/ExecutionBlock.h"
#include "Aql/ExecutionNode.h"
#include "Aql/IndexNode.h"
#include "Utils/AqlTransaction.h"
struct TRI_doc_mptr_t;
namespace arangodb {
struct OperationCursor;
namespace velocypack {
class Slice;
}
namespace aql {
class AqlItemBlock;
struct AstNode;
struct Collection;
class ExecutionEngine;
class IndexBlock : public ExecutionBlock {
public:
IndexBlock(ExecutionEngine* engine, IndexNode const* ep);
~IndexBlock();
/// @brief initialize, here we fetch all docs from the database
int initialize() override;
/// @brief initializeCursor, here we release our docs from this collection
int initializeCursor(AqlItemBlock* items, size_t pos) override;
AqlItemBlock* getSome(size_t atLeast, size_t atMost) override final;
// skip between atLeast and atMost, returns the number actually skipped . . .
// will only return less than atLeast if there aren't atLeast many
// things to skip overall.
size_t skipSome(size_t atLeast, size_t atMost) override final;
private:
/// @brief adds a SORT to a dynamic IN condition
arangodb::aql::AstNode* makeUnique(arangodb::aql::AstNode*) const;
/// @brief create an iterator object
std::shared_ptr<arangodb::OperationCursor> createCursor();
/// @brief Forwards _cursor to the next available index
void startNextCursor();
/// @brief Initializes the indexes
bool initIndexes();
/// @brief whether or not one of the bounds expressions requires V8
bool hasV8Expression() const;
/// @brief execute the bounds expressions
void executeExpressions();
/// @brief continue fetching of documents
bool readIndex(size_t atMost);
/// @brief frees the memory for all non-constant expressions
void cleanupNonConstExpressions();
private:
/// @brief collection
Collection const* _collection;
/// @brief document result
std::shared_ptr<OperationResult> _result;
/// @brief document buffer
std::vector<arangodb::velocypack::Slice> _documents;
/// @brief current position in _allDocs
size_t _posInDocs;
/// @brief current position in _indexes
size_t _currentIndex;
/// @brief _indexes holds all Indexes used in this block
std::vector<Transaction::IndexHandle> _indexes;
/// @brief _nonConstExpressions, list of all non const expressions, mapped
/// by their _condition node path indexes
std::vector<NonConstExpression*> _nonConstExpressions;
/// @brief _inVars, a vector containing for each expression above
/// a vector of Variable*, used to execute the expression
std::vector<std::vector<Variable const*>> _inVars;
/// @brief _inRegs, a vector containing for each expression above
/// a vector of RegisterId, used to execute the expression
std::vector<std::vector<RegisterId>> _inRegs;
/// @brief _cursor: holds the index cursor found using
/// getIndexCursor (if any) so that it can be read in chunks and not
/// necessarily all at once.
std::shared_ptr<arangodb::OperationCursor> _cursor;
/// @brief _condition: holds the complete condition this Block can serve for
AstNode const* _condition;
/// @brief set of already returned documents. Used to make the result distinct
std::unordered_set<std::string> _alreadyReturned;
/// @brief whether or not at least one expression uses v8
bool _hasV8Expression;
};
} // namespace arangodb::aql
} // namespace arangodb
#endif