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#ifndef nsDragHelperService_h__
#define nsDragHelperService_h__

#include "nsCOMPtr.h"
#include "nsIDragService.h"

#include <Carbon/Carbon.h>

#include "nsIDragHelperService.h"


//
// nsDragHelperService
//
// Implementation of nsIDragHelperService, a helper for managing
// drag and drop mechanics.
//

// {75993200-f3b2-11d5-a384-c7054d07d6fc}
#define NS_DRAGHELPERSERVICE_CID      \
{ 0x75993200, 0xf3b2, 0x11d5, { 0xa3, 0x84, 0xc7, 0x05, 0x4d, 0x07, 0xd6, 0xfc } }


class nsDragHelperService : public nsIDragHelperService
{
public:
  nsDragHelperService();
  virtual ~nsDragHelperService();

  NS_DECL_ISUPPORTS
  NS_DECL_NSIDRAGHELPERSERVICE

protected:

    // Send a drag event into Gecko
  PRBool DoDragAction(PRUint32      aMessage,
                      DragReference aDragRef,
                      nsIEventSink* aSink);

    // handles modifier keys (cmd, option, etc) and sets the appropriate 
    // action (move, copy, etc) based on the given modifiers.
  void SetDragActionBasedOnModifiers ( short inModifiers ) ;

    // Arranges to send NS_DRAGDROP_OVER events at regular intervals
  void SetDragOverTimer(nsIEventSink* aSink, DragRef aDragRef);
  static void DragOverTimerHandler(EventLoopTimerRef aTimer, void* aUserData);
  
    // holds our drag service across multiple calls to this callback. The reference to
    // the service is obtained when the mouse enters the window and is released when
    // the mouse leaves the window (or there is a drop). This prevents us from having
    // to re-establish the connection to the service manager 15 times a second when
    // handling the |kDragTrackingInWindow| message.
  nsCOMPtr<nsIDragService> mDragService;

    // Used to implement the NS_DRAGDROP_OVER timer
  EventLoopTimerRef      mDragOverTimer;
  nsCOMPtr<nsIEventSink> mDragOverSink;
  DragRef                mDragOverDragRef;
}; // nsDragHelperService


#endif // nsDragHelperService_h__