src/msw/ole/dropsrc.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/ole/dropsrc.cpp
   3 // Purpose:     implementation of wxIDropSource and wxDropSource
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:     10.05.98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
   9 // Licence:     wxWindows licence
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // For compilers that support precompilation, includes "wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #if defined(__BORLANDC__)
  24   #pragma hdrstop
  25 #endif
  26
  27 #if wxUSE_OLE && wxUSE_DRAG_AND_DROP
  28
  29 #ifndef WX_PRECOMP
  30     #include "wx/window.h"
  31     #include "wx/log.h"
  32 #endif
  33
  34 #include "wx/dnd.h"
  35
  36 #include "wx/msw/private.h"
  37
  38 // for some compilers, the entire ole2.h must be included, not only oleauto.h
  39 #if wxUSE_NORLANDER_HEADERS || defined(__WATCOMC__) || defined(__WXWINCE__)
  40     #include <ole2.h>
  41 #endif
  42
  43 #include <oleauto.h>
  44
  45 #include "wx/msw/ole/oleutils.h"
  46
  47 // ----------------------------------------------------------------------------
  48 // wxIDropSource implementation of IDropSource interface
  49 // ----------------------------------------------------------------------------
  50
  51 class wxIDropSource : public IDropSource
  52 {
  53 public:
  54   wxIDropSource(wxDropSource *pDropSource);
  55   virtual ~wxIDropSource() { }
  56
  57   // IDropSource
  58   STDMETHODIMP QueryContinueDrag(BOOL fEscapePressed, DWORD grfKeyState);
  59   STDMETHODIMP GiveFeedback(DWORD dwEffect);
  60
  61     DECLARE_IUNKNOWN_METHODS;
  62
  63 private:
  64   DWORD         m_grfInitKeyState;  // button which started the d&d operation
  65   wxDropSource *m_pDropSource;      // pointer to C++ class we belong to
  66
  67   wxDECLARE_NO_COPY_CLASS(wxIDropSource);
  68 };
  69
  70 // ============================================================================
  71 // Implementation
  72 // ============================================================================
  73
  74 // ----------------------------------------------------------------------------
  75 // wxIDropSource implementation
  76 // ----------------------------------------------------------------------------
  77 BEGIN_IID_TABLE(wxIDropSource)
  78   ADD_IID(Unknown)
  79   ADD_IID(DropSource)
  80 END_IID_TABLE;
  81
  82 IMPLEMENT_IUNKNOWN_METHODS(wxIDropSource)
  83
  84 wxIDropSource::wxIDropSource(wxDropSource *pDropSource)
  85 {
  86   wxASSERT( pDropSource != NULL );
  87
  88   m_pDropSource = pDropSource;
  89   m_grfInitKeyState = 0;
  90 }
  91
  92 // Name    : wxIDropSource::QueryContinueDrag
  93 // Purpose : decide if drag operation must be continued or not
  94 // Returns : HRESULT: S_OK              if we should continue
  95 //                    DRAGDROP_S_DROP   to drop right now
  96 //                    DRAGDROP_S_CANCEL to cancel everything
  97 // Params  : [in] BOOL  fEscapePressed  <Esc> pressed since last call?
  98 //           [in] DWORD grfKeyState     mask containing state of kbd keys
  99 // Notes   : as there is no reasonably simple portable way to implement this
 100 //           function, we currently don't give the possibility to override the
 101 //           default behaviour implemented here
 102 STDMETHODIMP wxIDropSource::QueryContinueDrag(BOOL fEscapePressed,
 103                                               DWORD grfKeyState)
 104 {
 105   if ( fEscapePressed )
 106     return DRAGDROP_S_CANCEL;
 107
 108   // initialize ourself with the drag begin button
 109   if ( m_grfInitKeyState == 0 ) {
 110     m_grfInitKeyState = grfKeyState & (MK_LBUTTON | MK_RBUTTON | MK_MBUTTON);
 111   }
 112
 113   if ( !(grfKeyState & m_grfInitKeyState) ) {
 114     // button which started d&d released, go!
 115     return DRAGDROP_S_DROP;
 116   }
 117
 118   return S_OK;
 119 }
 120
 121 // Name    : wxIDropSource::GiveFeedback
 122 // Purpose : give UI feedback according to current state of operation
 123 // Returns : STDMETHODIMP
 124 // Params  : [in] DWORD dwEffect - what would happen if we dropped now
 125 // Notes   : default implementation is ok in more than 99% of cases
 126 STDMETHODIMP wxIDropSource::GiveFeedback(DWORD dwEffect)
 127 {
 128   wxDragResult effect;
 129   if ( dwEffect & DROPEFFECT_COPY )
 130     effect = wxDragCopy;
 131   else if ( dwEffect & DROPEFFECT_MOVE )
 132     effect = wxDragMove;
 133   else
 134     effect = wxDragNone;
 135
 136   if ( m_pDropSource->GiveFeedback(effect) )
 137     return S_OK;
 138
 139   return DRAGDROP_S_USEDEFAULTCURSORS;
 140 }
 141
 142 // ----------------------------------------------------------------------------
 143 // wxDropSource implementation
 144 // ----------------------------------------------------------------------------
 145
 146 // ctors
 147
 148 // common part of all ctors
 149 void wxDropSource::Init()
 150 {
 151     m_pIDropSource = new wxIDropSource(this);
 152     m_pIDropSource->AddRef();
 153 }
 154
 155 wxDropSource::wxDropSource(wxWindow* WXUNUSED(win),
 156                            const wxCursor &cursorCopy,
 157                            const wxCursor &cursorMove,
 158                            const wxCursor &cursorStop)
 159             : wxDropSourceBase(cursorCopy, cursorMove, cursorStop)
 160 {
 161     Init();
 162 }
 163
 164 wxDropSource::wxDropSource(wxDataObject& data,
 165                            wxWindow* WXUNUSED(win),
 166                            const wxCursor &cursorCopy,
 167                            const wxCursor &cursorMove,
 168                            const wxCursor &cursorStop)
 169             : wxDropSourceBase(cursorCopy, cursorMove, cursorStop)
 170 {
 171     Init();
 172     SetData(data);
 173 }
 174
 175 wxDropSource::~wxDropSource()
 176 {
 177     m_pIDropSource->Release();
 178 }
 179
 180 // Name    : DoDragDrop
 181 // Purpose : start drag and drop operation
 182 // Returns : wxDragResult - the code of performed operation
 183 // Params  : [in] int flags: specifies if moving is allowe (or only copying)
 184 // Notes   : you must call SetData() before if you had used def ctor
 185 wxDragResult wxDropSource::DoDragDrop(int flags)
 186 {
 187   wxCHECK_MSG( m_data != NULL, wxDragNone, wxT("No data in wxDropSource!") );
 188
 189   DWORD dwEffect;
 190   HRESULT hr = ::DoDragDrop(m_data->GetInterface(),
 191                             m_pIDropSource,
 192                             (flags & wxDrag_AllowMove)
 193                                 ? DROPEFFECT_COPY | DROPEFFECT_MOVE
 194                                 : DROPEFFECT_COPY,
 195                             &dwEffect);
 196
 197   if ( hr == DRAGDROP_S_CANCEL ) {
 198     return wxDragCancel;
 199   }
 200   else if ( hr == DRAGDROP_S_DROP ) {
 201     if ( dwEffect & DROPEFFECT_COPY ) {
 202       return wxDragCopy;
 203     }
 204     else if ( dwEffect & DROPEFFECT_MOVE ) {
 205       // consistency check: normally, we shouldn't get "move" at all
 206       // here if we don't allow it, but in practice it does happen quite often
 207       return (flags & wxDrag_AllowMove) ? wxDragMove : wxDragCopy;
 208     }
 209     else {
 210       // not copy or move
 211       return wxDragNone;
 212     }
 213   }
 214   else {
 215     if ( FAILED(hr) ) {
 216       wxLogApiError(wxT("DoDragDrop"), hr);
 217       wxLogError(wxT("Drag & drop operation failed."));
 218     }
 219     else {
 220       wxLogDebug(wxT("Unexpected success return code %08lx from DoDragDrop."),
 221                  hr);
 222     }
 223
 224     return wxDragError;
 225   }
 226 }
 227
 228 // Name    : wxDropSource::GiveFeedback
 229 // Purpose : visually inform the user about d&d operation state
 230 // Returns : bool: true if we do all ourselves or false for default feedback
 231 // Params  : [in] DragResult effect - what would happen if we dropped now
 232 // Notes   : here we just leave this stuff for default implementation
 233 bool wxDropSource::GiveFeedback(wxDragResult effect)
 234 {
 235     const wxCursor& cursor = GetCursor(effect);
 236     if ( cursor.IsOk() )
 237     {
 238         ::SetCursor((HCURSOR)cursor.GetHCURSOR());
 239
 240         return true;
 241     }
 242     else
 243     {
 244         return false;
 245     }
 246 }
 247
 248 #endif  // wxUSE_OLE && wxUSE_DRAG_AND_DROP