MeVis/Foundation/Sources/ML/include/host/mlPageRequestCursor.h

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// **InsertLicense** code
//-------------------------------------------------------------------------
//-------------------------------------------------------------------------
#ifndef __mlPageRequestCursor_H
#define __mlPageRequestCursor_H

// ML-includes
#ifndef __mlInitSystemML_H
#include "mlInitSystemML.h"
#endif

#include <set>

ML_START_NAMESPACE

class TileRequest;
class PageRequest;
class PageRequestQueueInterface;

#define ML_PAGEREQUEST_TILES_NOT_CREATED -1
#define ML_TILEREQUEST_PAGES_NOT_CREATED -1

//-------------------------------------------------------------------------------------------
//-------------------------------------------------------------------------------------------
class ML_UNIX_ONLY_EXPORT(MLEXPORT) PageRequestCursor
{
public:
  PageRequestCursor(PageRequest* request);
  PageRequestCursor(TileRequest* request);
  PageRequestCursor();

  void init(TileRequest* request);

  enum CursorState {
    HasMoreWork, 
    HasFinished, 
    IsBlocked    
  };

  CursorState nextStep(PageRequestQueueInterface& queue);

  bool propagateCancellationDownIfRequestNotNeededAnymore();

  void collectPageRequestsWithErrors(std::set<PageRequest*>& result);

  bool isNeeded();

  void clear();

private:
  void moveUpToNextDown();

  PageRequest* _pageRequest;
  TileRequest* _tileRequest;

  int          _currentDepth;
};

ML_END_NAMESPACE

#endif //of __mlPageRequestCursor_H