////////////////////////////////////////////////////////////////////////////////
/// @brief AQL SubqueryBlock
///
/// @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_SUBQUERY_BLOCK_H
#define ARANGODB_AQL_SUBQUERY_BLOCK_H 1

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

namespace triagens {
  namespace aql {

    class AqlItemBlock;

    class ExecutionEngine;

// -----------------------------------------------------------------------------
// --SECTION--                                                     SubqueryBlock
// -----------------------------------------------------------------------------

    class SubqueryBlock : public ExecutionBlock {

      public:

        SubqueryBlock (ExecutionEngine*,
                       SubqueryNode const*,
                       ExecutionBlock*);

////////////////////////////////////////////////////////////////////////////////
/// @brief destructor
////////////////////////////////////////////////////////////////////////////////

        ~SubqueryBlock ();

////////////////////////////////////////////////////////////////////////////////
/// @brief initialize, tell dependency and the subquery
////////////////////////////////////////////////////////////////////////////////

        int initialize () override;

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

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

////////////////////////////////////////////////////////////////////////////////
/// @brief shutdown, tell dependency and the subquery
////////////////////////////////////////////////////////////////////////////////

        int shutdown (int errorCode) override final;

////////////////////////////////////////////////////////////////////////////////
/// @brief getter for the pointer to the subquery
////////////////////////////////////////////////////////////////////////////////

        ExecutionBlock* getSubquery() {
          return _subquery;
        }

      private:

////////////////////////////////////////////////////////////////////////////////
/// @brief execute the subquery and return its results
////////////////////////////////////////////////////////////////////////////////

        std::vector<AqlItemBlock*>* executeSubquery ();

////////////////////////////////////////////////////////////////////////////////
/// @brief destroy the results of a subquery
////////////////////////////////////////////////////////////////////////////////

        void destroySubqueryResults (std::vector<AqlItemBlock*>*);

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

        RegisterId _outReg;

////////////////////////////////////////////////////////////////////////////////
/// @brief we need to have an executionblock and where to write the result
////////////////////////////////////////////////////////////////////////////////

        ExecutionBlock* _subquery;
    };

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

#endif

// Local Variables:
// mode: outline-minor
// outline-regexp: "^\\(/// @brief\\|/// {@inheritDoc}\\|/// @addtogroup\\|// --SECTION--\\|/// @\\}\\)"
// End: