////////////////////////////////////////////////////////////////////////////////
/// @brief AQL CalculationBlock
///
/// @file 
///
/// DISCLAIMER
///
/// Copyright 2010-2014 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 triAGENS GmbH, Cologne, Germany
///
/// @author Max Neunhoeffer
/// @author Copyright 2014, triagens GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGODB_AQL_CALCULATION_BLOCK_H
#define ARANGODB_AQL_CALCULATION_BLOCK_H 1

#include "Aql/ExecutionBlock.h"
#include "Aql/ExecutionNode.h"
#include "Utils/AqlTransaction.h"

namespace triagens {
  namespace aql {

    class AqlItemBlock;

    class ExecutionEngine;

// -----------------------------------------------------------------------------
// --SECTION--                                                  CalculationBlock
// -----------------------------------------------------------------------------

    class CalculationBlock : public ExecutionBlock {

      public:

        CalculationBlock (ExecutionEngine*,
                          CalculationNode const*);

        ~CalculationBlock ();

        int initialize () override;

      private:

////////////////////////////////////////////////////////////////////////////////
/// @brief fill the target register in the item block with a reference to 
/// another variable
////////////////////////////////////////////////////////////////////////////////

        void fillBlockWithReference (AqlItemBlock*);

////////////////////////////////////////////////////////////////////////////////
/// @brief shared code for executing a simple or a V8 expression
////////////////////////////////////////////////////////////////////////////////

        void executeExpression (AqlItemBlock*);

////////////////////////////////////////////////////////////////////////////////
/// @brief doEvaluation, private helper to do the work
////////////////////////////////////////////////////////////////////////////////

        void doEvaluation (AqlItemBlock*);

      public:

////////////////////////////////////////////////////////////////////////////////
/// @brief getSome
////////////////////////////////////////////////////////////////////////////////

        AqlItemBlock* getSome (size_t atLeast,
                               size_t atMost) override final;

      private:

////////////////////////////////////////////////////////////////////////////////
/// @brief we hold a pointer to the expression in the plan
////////////////////////////////////////////////////////////////////////////////

        Expression* _expression;

////////////////////////////////////////////////////////////////////////////////
/// @brief info about input variables
////////////////////////////////////////////////////////////////////////////////

        std::vector<Variable const*> _inVars;

////////////////////////////////////////////////////////////////////////////////
/// @brief info about input registers
////////////////////////////////////////////////////////////////////////////////

        std::vector<RegisterId> _inRegs;

////////////////////////////////////////////////////////////////////////////////
/// @brief output register
////////////////////////////////////////////////////////////////////////////////

        RegisterId _outReg;

////////////////////////////////////////////////////////////////////////////////
/// @brief condition variable register
////////////////////////////////////////////////////////////////////////////////

        RegisterId _conditionReg;

////////////////////////////////////////////////////////////////////////////////
/// @brief whether or not the expression is a simple variable reference
////////////////////////////////////////////////////////////////////////////////

        bool _isReference;

    };

  }  // namespace triagens::aql
}  // namespace triagens

#endif

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