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arangodb/arangod/Aql/InAndOutRowExpressionContext.h

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////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2019-2019 ArangoDB 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 Michael Hackstein
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_AQL_IN_AND_OUT_ROW_EXPRESSION_CONTEXT_H
#define ARANGOD_AQL_IN_AND_OUT_ROW_EXPRESSION_CONTEXT_H 1
#include "QueryExpressionContext.h"
#include "Aql/AqlValue.h"
#include "Aql/InputAqlItemRow.h"
namespace arangodb {
namespace aql {
class Query;
/**
* @brief Context for expression evaluation that allows
* to read registers from Input and Output.
* This is useful for expressions that need
* to evaluate variables created by the active block.
* User needs to make sure that outputblock is written to!
*/
class InAndOutRowExpressionContext final : public QueryExpressionContext {
public:
InAndOutRowExpressionContext(Query* query, std::vector<Variable const*> const&& vars,
std::vector<RegisterId> const&& regs, size_t vertexVarIdx,
size_t edgeVarIdx, size_t pathVarIdx);
~InAndOutRowExpressionContext() override = default;
void setInputRow(InputAqlItemRow input);
void invalidateInputRow();
size_t numRegisters() const override;
AqlValue getVariableValue(Variable const* variable, bool doCopy,
bool& mustDestroy) const override;
bool needsVertexValue() const;
bool needsEdgeValue() const;
bool needsPathValue() const;
/// @brief inject the result value when asked for the Vertex data
/// This will not copy ownership of slice content. caller needs to make sure
/// that the buffer stays valid until evaluate is called
void setVertexValue(velocypack::Slice v);
/// @brief inject the result value when asked for the Edge data
/// This will not copy ownership of slice content. caller needs to make sure
/// that the buffer stays valid until evaluate is called
void setEdgeValue(velocypack::Slice e);
/// @brief inject the result value when asked for the Path data
/// This will not copy ownership of slice content. caller needs to make sure
/// that the buffer stays valid until evaluate is called
void setPathValue(velocypack::Slice p);
private:
InputAqlItemRow _input;
std::vector<Variable const*> const _vars;
std::vector<RegisterId> const _regs;
size_t const _vertexVarIdx;
size_t const _edgeVarIdx;
size_t const _pathVarIdx;
AqlValue _vertexValue;
AqlValue _edgeValue;
AqlValue _pathValue;
};
} // namespace aql
} // namespace arangodb
#endif