src/msw/ole/dropsrc.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        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 license
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 #ifdef __GNUG__
  21   #pragma implementation "dropsrc.h"
  22 #endif
  23
  24 // For compilers that support precompilation, includes "wx.h".
  25 #include "wx/wxprec.h"
  26
  27 #if defined(__BORLANDC__)
  28   #pragma hdrstop
  29 #endif
  30
  31 #include "wx/setup.h"
  32
  33 #if wxUSE_DRAG_AND_DROP
  34
  35 #include "wx/log.h"
  36 #include "wx/dataobj.h"
  37 #include "wx/msw/ole/dropsrc.h"
  38
  39 #include <windows.h>
  40
  41 #ifndef __WIN32__
  42   #include <ole2.h>
  43   #include <olestd.h>
  44 #endif
  45
  46 #include <oleauto.h>
  47
  48 #include "wx/msw/ole/oleutils.h"
  49
  50 // ----------------------------------------------------------------------------
  51 // wxIDropSource implementation of IDropSource interface
  52 // ----------------------------------------------------------------------------
  53
  54 class wxIDropSource : public IDropSource
  55 {
  56 public:
  57   wxIDropSource(wxDropSource *pDropSource);
  58
  59   DECLARE_IUNKNOWN_METHODS;
  60
  61   // IDropSource
  62   STDMETHODIMP QueryContinueDrag(BOOL fEscapePressed, DWORD grfKeyState);
  63   STDMETHODIMP GiveFeedback(DWORD dwEffect);
  64
  65 private:
  66   DWORD         m_grfInitKeyState;  // button which started the d&d operation
  67   wxDropSource *m_pDropSource;      // pointer to C++ class we belong to
  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   m_cRef = 0;
  91 }
  92
  93 // Name    : wxIDropSource::QueryContinueDrag
  94 // Purpose : decide if drag operation must be continued or not
  95 // Returns : HRESULT: S_OK              if we should continue
  96 //                    DRAGDROP_S_DROP   to drop right now
  97 //                    DRAGDROP_S_CANCEL to cancel everything
  98 // Params  : [in] BOOL  fEscapePressed  <Esc> pressed since last call?
  99 //           [in] DWORD grfKeyState     mask containing state of kbd keys
 100 // Notes   : as there is no reasonably simple portable way to implement this
 101 //           function, we currently don't give the possibility to override the
 102 //           default behaviour implemented here
 103 STDMETHODIMP wxIDropSource::QueryContinueDrag(BOOL fEscapePressed,
 104                                               DWORD grfKeyState)
 105 {
 106   if ( fEscapePressed )
 107     return DRAGDROP_S_CANCEL;
 108
 109   // initialize ourself with the drag begin button
 110   if ( m_grfInitKeyState == 0 ) {
 111     m_grfInitKeyState = grfKeyState & (MK_LBUTTON | MK_RBUTTON | MK_MBUTTON);
 112   }
 113
 114   if ( !(grfKeyState & m_grfInitKeyState) ) {
 115     // button which started d&d released, go!
 116     return DRAGDROP_S_DROP;
 117   }
 118
 119   return S_OK;
 120 }
 121
 122 // Name    : wxIDropSource::GiveFeedback
 123 // Purpose : give UI feedback according to current state of operation
 124 // Returns : STDMETHODIMP
 125 // Params  : [in] DWORD dwEffect - what would happen if we dropped now
 126 // Notes   : default implementation is ok in more than 99% of cases
 127 STDMETHODIMP wxIDropSource::GiveFeedback(DWORD dwEffect)
 128 {
 129   wxDragResult effect;
 130   if ( dwEffect & DROPEFFECT_COPY )
 131     effect = wxDragCopy;
 132   else if ( dwEffect & DROPEFFECT_MOVE )
 133     effect = wxDragMove;
 134   else
 135     effect = wxDragNone;
 136
 137   if ( m_pDropSource->GiveFeedback(effect,
 138                                    (dwEffect & DROPEFFECT_SCROLL) != 0 ) )
 139     return S_OK;
 140
 141   return DRAGDROP_S_USEDEFAULTCURSORS;
 142 }
 143
 144 // ----------------------------------------------------------------------------
 145 // wxDropSource implementation
 146 // ----------------------------------------------------------------------------
 147
 148 // ctors
 149
 150 // common part of all ctors
 151 void wxDropSource::Init()
 152 {
 153   m_pIDropSource = new wxIDropSource(this);
 154   m_pIDropSource->AddRef();
 155 }
 156
 157 wxDropSource::wxDropSource(wxWindow* WXUNUSED(win))
 158 {
 159   Init();
 160   m_pData = NULL;
 161 }
 162
 163 wxDropSource::wxDropSource(wxDataObject& data, wxWindow* WXUNUSED(win))
 164 {
 165   Init();
 166   SetData(data);
 167 }
 168
 169 void wxDropSource::SetData(wxDataObject& data)
 170 {
 171   m_pData = &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] bool bAllowMove: if false, only copy is allowed
 183 // Notes   : you must call SetData() before if you had used def ctor
 184 wxDragResult wxDropSource::DoDragDrop(bool bAllowMove)
 185 {
 186   wxCHECK_MSG( m_pData != NULL, wxDragNone, _T("No data in wxDropSource!") );
 187
 188   DWORD dwEffect;
 189   HRESULT hr = ::DoDragDrop(m_pData->GetInterface(),
 190                             m_pIDropSource,
 191                             bAllowMove ? DROPEFFECT_COPY | DROPEFFECT_MOVE
 192                                        : DROPEFFECT_COPY,
 193                             &dwEffect);
 194
 195   if ( hr == DRAGDROP_S_CANCEL ) {
 196     return wxDragCancel;
 197   }
 198   else if ( hr == DRAGDROP_S_DROP ) {
 199     if ( dwEffect & DROPEFFECT_COPY ) {
 200       return wxDragCopy;
 201     }
 202     else if ( dwEffect & DROPEFFECT_MOVE ) {
 203       // consistency check: normally, we shouldn't get "move" at all
 204       // here if !bAllowMove, but in practice it does happen quite often
 205       if ( bAllowMove )
 206         return wxDragMove;
 207       else
 208         return wxDragCopy;
 209     }
 210     else {
 211       // not copy or move
 212       return wxDragNone;
 213     }
 214   }
 215   else {
 216     if ( FAILED(hr) ) {
 217       wxLogApiError("DoDragDrop", hr);
 218       wxLogError(_T("Drag & drop operation failed."));
 219     }
 220     else {
 221       wxLogDebug(_T("Unexpected success return code %08lx from DoDragDrop."), 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 //           [in] bool bScrolling   - true if target is scrolling
 233 // Notes   : here we just leave this stuff for default implementation
 234 bool wxDropSource::GiveFeedback(wxDragResult effect, bool bScrolling)
 235 {
 236   return FALSE;
 237 }
 238
 239 #endif  //USE_DRAG_AND_DROP