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