arangodb/arangod/Utils/Cursor.h

////////////////////////////////////////////////////////////////////////////////
/// @brief cursor
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2014 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 Copyright 2014, ArangoDB GmbH, Cologne, Germany
/// @author Copyright 2012-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGODB_ARANGO_CURSOR_H
#define ARANGODB_ARANGO_CURSOR_H 1

#include "Basics/Common.h"
#include "Basics/StringBuffer.h"
#include "VocBase/voc-types.h"

struct TRI_json_t;
struct TRI_vocbase_t;

namespace triagens {
  namespace arango {

    class CollectionExport;

// -----------------------------------------------------------------------------
// --SECTION--                                                      class Cursor
// -----------------------------------------------------------------------------

    typedef TRI_voc_tick_t CursorId;

    class Cursor {
      public:

        Cursor (Cursor const&) = delete;
        Cursor& operator= (Cursor const&) = delete;

        Cursor (CursorId,
                size_t,
                struct TRI_json_t*,
                double,
                bool);

        virtual ~Cursor ();

// -----------------------------------------------------------------------------
// --SECTION--                                                  public functions
// -----------------------------------------------------------------------------

      public:

        CursorId id () const {
          return _id;
        }

        size_t batchSize () const {
          return _batchSize;
        }

        struct TRI_json_t* extra () const {
          return _extra;
        }

        bool hasCount () const {
          return _hasCount;
        }

        double ttl () const {
          return _ttl;
        }
        
        double expires () const {
          return _expires;
        }

        bool isUsed () const {
          return _isUsed;
        }

        bool isDeleted () const {
          return _isDeleted;
        }

        void deleted () {
          _isDeleted = true;
        }

        void use () {
          TRI_ASSERT(! _isDeleted);
          TRI_ASSERT(! _isUsed);

          _isUsed = true;
          _expires = TRI_microtime() + _ttl;
        }

        void release () {
          TRI_ASSERT(_isUsed);
          _isUsed = false;
        }
        
        virtual bool hasNext () = 0;

        virtual struct TRI_json_t* next () = 0;
        
        virtual size_t count () const = 0;

        virtual void dump (triagens::basics::StringBuffer&) = 0;

// -----------------------------------------------------------------------------
// --SECTION--                                               protected variables
// -----------------------------------------------------------------------------

      protected:

        CursorId const        _id;
        size_t const          _batchSize;
        size_t                _position;
        struct TRI_json_t*    _extra;
        double                _ttl;
        double                _expires;
        bool const            _hasCount;
        bool                  _isDeleted;
        bool                  _isUsed;
    };

// -----------------------------------------------------------------------------
// --SECTION--                                                  class JsonCursor
// -----------------------------------------------------------------------------
    
    class JsonCursor : public Cursor {
      public:

        JsonCursor (TRI_vocbase_t*,
                    CursorId,
                    struct TRI_json_t*, 
                    size_t,
                    struct TRI_json_t*,
                    double,
                    bool,
                    bool);

        ~JsonCursor ();

// -----------------------------------------------------------------------------
// --SECTION--                                                  public functions
// -----------------------------------------------------------------------------

      public:

        bool hasNext () override final;

        struct TRI_json_t* next () override final;
        
        size_t count () const override final;

        void dump (triagens::basics::StringBuffer&) override final;

// -----------------------------------------------------------------------------
// --SECTION--                                                 private functions
// -----------------------------------------------------------------------------

      private:

        void freeJson ();

// -----------------------------------------------------------------------------
// --SECTION--                                                 private variables
// -----------------------------------------------------------------------------

      private:

        TRI_vocbase_t*        _vocbase;
        struct TRI_json_t*    _json;
        size_t const          _size;
        bool                  _cached;
    };

// -----------------------------------------------------------------------------
// --SECTION--                                                class ExportCursor
// -----------------------------------------------------------------------------
    
    class ExportCursor : public Cursor {
      public:

        ExportCursor (TRI_vocbase_t*,
                      CursorId,
                      triagens::arango::CollectionExport*,
                      size_t,
                      double,
                      bool);

        ~ExportCursor ();

// -----------------------------------------------------------------------------
// --SECTION--                                                  public functions
// -----------------------------------------------------------------------------

      public:

        bool hasNext () override final;

        struct TRI_json_t* next () override final;
        
        size_t count () const override final;

        void dump (triagens::basics::StringBuffer&) override final;

// -----------------------------------------------------------------------------
// --SECTION--                                                 private variables
// -----------------------------------------------------------------------------

      private:

        TRI_vocbase_t*                      _vocbase;
        triagens::arango::CollectionExport* _ex;
        size_t const                        _size;
    };

  }
}

#endif

// -----------------------------------------------------------------------------
// --SECTION--                                                       END-OF-FILE
// -----------------------------------------------------------------------------

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