widget/windows/nsNativeDragTarget.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5 #ifndef _nsNativeDragTarget_h_
   6 #define _nsNativeDragTarget_h_
   7
   8 #include "nsCOMPtr.h"
   9 #include <ole2.h>
  10 #include <shlobj.h>
  11
  12 #ifndef IDropTargetHelper
  13 #  include <shobjidl.h>  // Vista drag image interfaces
  14 #  undef LogSeverity     // SetupAPI.h #defines this as DWORD
  15 #endif
  16
  17 #include "mozilla/Attributes.h"
  18 #include "mozilla/EventForwards.h"
  19
  20 class nsIDragService;
  21 class nsIWidget;
  22
  23 /*
  24  * nsNativeDragTarget implements the IDropTarget interface and gets most of its
  25  * behavior from the associated adapter (m_dragDrop).
  26  */
  27
  28 class nsNativeDragTarget final : public IDropTarget {
  29  public:
  30   explicit nsNativeDragTarget(nsIWidget* aWidget);
  31   ~nsNativeDragTarget();
  32
  33   // IUnknown members - see iunknown.h for documentation
  34   STDMETHODIMP QueryInterface(REFIID, void**);
  35   STDMETHODIMP_(ULONG) AddRef();
  36   STDMETHODIMP_(ULONG) Release();
  37
  38   // IDataTarget members
  39
  40   // Set pEffect based on whether this object can support a drop based on
  41   // the data available from pSource, the key and mouse states specified
  42   // in grfKeyState, and the coordinates specified by point. This is
  43   // called by OLE when a drag enters this object's window (as registered
  44   // by Initialize).
  45   STDMETHODIMP DragEnter(LPDATAOBJECT pSource, DWORD grfKeyState, POINTL point,
  46                          DWORD* pEffect);
  47
  48   // Similar to DragEnter except it is called frequently while the drag
  49   // is over this object's window.
  50   MOZ_CAN_RUN_SCRIPT_BOUNDARY STDMETHODIMP DragOver(DWORD grfKeyState,
  51                                                     POINTL point,
  52                                                     DWORD* pEffect);
  53
  54   // Release the drag-drop source and put internal state back to the point
  55   // before the call to DragEnter. This is called when the drag leaves
  56   // without a drop occurring.
  57   MOZ_CAN_RUN_SCRIPT_BOUNDARY STDMETHODIMP DragLeave();
  58
  59   // If point is within our region of interest and pSource's data supports
  60   // one of our formats, get the data and set pEffect according to
  61   // grfKeyState (DROPEFFECT_MOVE if the control key was not pressed,
  62   // DROPEFFECT_COPY if the control key was pressed). Otherwise return
  63   // E_FAIL.
  64   MOZ_CAN_RUN_SCRIPT_BOUNDARY STDMETHODIMP Drop(LPDATAOBJECT pSource,
  65                                                 DWORD grfKeyState, POINTL point,
  66                                                 DWORD* pEffect);
  67   /**
  68    * Cancel the current drag session, if any.
  69    */
  70   MOZ_CAN_RUN_SCRIPT_BOUNDARY void DragCancel();
  71
  72   static void DragImageChanged() { gDragImageChanged = true; }
  73
  74  protected:
  75   void GetGeckoDragAction(DWORD grfKeyState, LPDWORD pdwEffect,
  76                           uint32_t* aGeckoAction);
  77   void ProcessDrag(mozilla::EventMessage aEventMessage, DWORD grfKeyState,
  78                    POINTL pt, DWORD* pdwEffect);
  79   void DispatchDragDropEvent(mozilla::EventMessage aEventMessage,
  80                              const POINTL& aPT);
  81   void AddLinkSupportIfCanBeGenerated(LPDATAOBJECT aIDataSource);
  82
  83   // Native Stuff
  84   ULONG m_cRef;  // reference count
  85   HWND mHWnd;
  86   DWORD mEffectsAllowed;
  87   DWORD mEffectsPreferred;
  88   bool mTookOwnRef;
  89
  90   // Gecko Stuff
  91   nsIWidget* mWidget;
  92   nsCOMPtr<nsIDragService> mDragService;
  93   // Drag target helper
  94   IDropTargetHelper* GetDropTargetHelper();
  95
  96  private:
  97   // Drag target helper
  98   IDropTargetHelper* mDropTargetHelper;
  99
 100   static bool gDragImageChanged;
 101 };
 102
 103 #endif  // _nsNativeDragTarget_h_