////////////////////////////////////////////////////////////////////////////////
/// @brief list of cursors present in database
///
/// @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_CURSORS_H
#define ARANGODB_ARANGO_CURSORS_H 1

#include "Basics/Common.h"
#include "Basics/Mutex.h"
#include "Utils/Cursor.h"
#include "VocBase/voc-types.h"

struct TRI_json_t;
struct TRI_vocbase_t;

namespace triagens {
  namespace arango {

    class CollectionExport;

// -----------------------------------------------------------------------------
// --SECTION--                                            class CursorRepository
// -----------------------------------------------------------------------------

    class CursorRepository {

// -----------------------------------------------------------------------------
// --SECTION--                                        constructors / destructors
// -----------------------------------------------------------------------------

      public:

////////////////////////////////////////////////////////////////////////////////
/// @brief create a cursors repository
////////////////////////////////////////////////////////////////////////////////

        explicit CursorRepository (TRI_vocbase_t*);

////////////////////////////////////////////////////////////////////////////////
/// @brief destroy a cursors repository
////////////////////////////////////////////////////////////////////////////////

        ~CursorRepository ();

// -----------------------------------------------------------------------------
// --SECTION--                                                    public methods
// -----------------------------------------------------------------------------

      public:

////////////////////////////////////////////////////////////////////////////////
/// @brief creates a cursor and stores it in the registry
/// the cursor will be returned with the usage flag set to true. it must be
/// returned later using release() 
/// the cursor will take ownership of both json and extra
////////////////////////////////////////////////////////////////////////////////

        JsonCursor* createFromJson (struct TRI_json_t*,
                                    size_t,
                                    struct TRI_json_t*,
                                    double, 
                                    bool,
                                    bool);

////////////////////////////////////////////////////////////////////////////////
/// @brief creates a cursor and stores it in the registry
////////////////////////////////////////////////////////////////////////////////

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

////////////////////////////////////////////////////////////////////////////////
/// @brief remove a cursor by id
////////////////////////////////////////////////////////////////////////////////

        bool remove (CursorId);

////////////////////////////////////////////////////////////////////////////////
/// @brief find an existing cursor by id
/// if found, the cursor will be returned with the usage flag set to true. 
/// it must be returned later using release() 
////////////////////////////////////////////////////////////////////////////////

        Cursor* find (CursorId,
                      bool&);

////////////////////////////////////////////////////////////////////////////////
/// @brief return a cursor
////////////////////////////////////////////////////////////////////////////////

        void release (Cursor*);

////////////////////////////////////////////////////////////////////////////////
/// @brief whether or not the repository contains a used cursor
////////////////////////////////////////////////////////////////////////////////

        bool containsUsedCursor ();

////////////////////////////////////////////////////////////////////////////////
/// @brief run a garbage collection on the cursors
////////////////////////////////////////////////////////////////////////////////

        bool garbageCollect (bool);

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

      private:

////////////////////////////////////////////////////////////////////////////////
/// @brief vocbase
////////////////////////////////////////////////////////////////////////////////

        TRI_vocbase_t* _vocbase;

////////////////////////////////////////////////////////////////////////////////
/// @brief mutex for the cursors repository
////////////////////////////////////////////////////////////////////////////////

        triagens::basics::Mutex _lock;

////////////////////////////////////////////////////////////////////////////////
/// @brief list of current cursors
////////////////////////////////////////////////////////////////////////////////

        std::unordered_map<CursorId, Cursor*> _cursors;

////////////////////////////////////////////////////////////////////////////////
/// @brief maximum number of cursors to garbage-collect in one go
////////////////////////////////////////////////////////////////////////////////

        static size_t const MaxCollectCount;
    };

  }
}

#endif

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

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