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 USE_DRAG_AND_DROP
  34
  35 #include  <wx/log.h>
  36 #include  <wx/msw/ole/oleutils.h>
  37 #include  <wx/msw/ole/dataobj.h>
  38 #include  <wx/msw/ole/dropsrc.h>
  39
  40 #ifndef __WIN32__
  41   #include <ole2.h>
  42   #include <olestd.h>
  43 #endif
  44
  45 // ----------------------------------------------------------------------------
  46 // wxIDropSource implementation of IDropSource interface
  47 // ----------------------------------------------------------------------------
  48
  49 class wxIDropSource : public IDropSource
  50 {
  51 public:
  52   wxIDropSource(wxDropSource *pDropSource);
  53
  54   DECLARE_IUNKNOWN_METHODS;
  55
  56   // IDropSource
  57   STDMETHODIMP QueryContinueDrag(BOOL fEscapePressed, DWORD grfKeyState);
  58   STDMETHODIMP GiveFeedback(DWORD dwEffect);
  59
  60 private:
  61   DWORD         m_grfInitKeyState;  // button which started the d&d operation
  62   wxDropSource *m_pDropSource;      // pointer to C++ class we belong to
  63 };
  64
  65 // ============================================================================
  66 // Implementation
  67 // ============================================================================
  68
  69 // ----------------------------------------------------------------------------
  70 // wxIDropSource implementation
  71 // ----------------------------------------------------------------------------
  72 BEGIN_IID_TABLE(wxIDropSource)
  73   ADD_IID(Unknown)
  74   ADD_IID(DropSource)
  75 END_IID_TABLE;
  76
  77 IMPLEMENT_IUNKNOWN_METHODS(wxIDropSource)
  78
  79 wxIDropSource::wxIDropSource(wxDropSource *pDropSource)
  80 {
  81   wxASSERT( pDropSource != NULL );
  82
  83   m_pDropSource = pDropSource;
  84   m_grfInitKeyState = 0;
  85   m_cRef = 0;
  86 }
  87
  88 // Name    : wxIDropSource::QueryContinueDrag
  89 // Purpose : decide if drag operation must be continued or not
  90 // Returns : HRESULT: S_OK              if we should continue
  91 //                    DRAGDROP_S_DROP   to drop right now
  92 //                    DRAGDROP_S_CANCEL to cancel everything
  93 // Params  : [in] BOOL  fEscapePressed  <Esc> pressed since last call?
  94 //           [in] DWORD grfKeyState     mask containing state of kbd keys
  95 // Notes   : as there is no reasonably simple portable way to implement this
  96 //           function, we currently don't give the possibility to override the
  97 //           default behaviour implemented here
  98 STDMETHODIMP wxIDropSource::QueryContinueDrag(BOOL fEscapePressed,
  99                                               DWORD grfKeyState)
 100 {
 101   if ( fEscapePressed )
 102     return DRAGDROP_S_CANCEL;
 103
 104   // initialize ourself with the drag begin button
 105   if ( m_grfInitKeyState == 0 ) {
 106     m_grfInitKeyState = grfKeyState & (MK_LBUTTON | MK_RBUTTON | MK_MBUTTON);
 107   }
 108
 109   if ( !(grfKeyState & m_grfInitKeyState) ) {
 110     // button which started d&d released, go!
 111     return DRAGDROP_S_DROP;
 112   }
 113
 114   return S_OK;
 115 }
 116
 117 // Name    : wxIDropSource::GiveFeedback
 118 // Purpose : give UI feedback according to current state of operation
 119 // Returns : STDMETHODIMP
 120 // Params  : [in] DWORD dwEffect - what would happen if we dropped now
 121 // Notes   : default implementation is ok in more than 99% of cases
 122 STDMETHODIMP wxIDropSource::GiveFeedback(DWORD dwEffect)
 123 {
 124   wxDropSource::DragResult effect;
 125   if ( dwEffect & DROPEFFECT_COPY )
 126     effect = wxDropSource::Copy;
 127   else if ( dwEffect & DROPEFFECT_MOVE )
 128     effect = wxDropSource::Move;
 129   else
 130     effect = wxDropSource::None;
 131
 132   if ( m_pDropSource->GiveFeedback(effect,
 133                                    (dwEffect & DROPEFFECT_SCROLL) != 0 ) )
 134     return S_OK;
 135
 136   return DRAGDROP_S_USEDEFAULTCURSORS;
 137 }
 138
 139 // ----------------------------------------------------------------------------
 140 // wxDropSource implementation
 141 // ----------------------------------------------------------------------------
 142
 143 // ctors
 144
 145 // common part of all ctors
 146 void wxDropSource::Init()
 147 {
 148   m_pIDropSource = new wxIDropSource(this);
 149   m_pIDropSource->AddRef();
 150 }
 151
 152 wxDropSource::wxDropSource()
 153 {
 154   Init();
 155   m_pData = NULL;
 156 }
 157
 158 wxDropSource::wxDropSource(wxDataObject& data)
 159 {
 160   Init();
 161   SetData(data);
 162 }
 163
 164 void wxDropSource::SetData(wxDataObject& data)
 165 {
 166   m_pData = &data;
 167 }
 168
 169 wxDropSource::~wxDropSource()
 170 {
 171   m_pIDropSource->Release();
 172 }
 173
 174 // Name    : DoDragDrop
 175 // Purpose : start drag and drop operation
 176 // Returns : DragResult - the code of performed operation
 177 // Params  : [in] bool bAllowMove: if false, only copy is allowed
 178 // Notes   : you must call SetData() before if you had used def ctor
 179 wxDropSource::DragResult wxDropSource::DoDragDrop(bool bAllowMove)
 180 {
 181   wxCHECK_MSG( m_pData != NULL, None, "No data in wxDropSource!" );
 182
 183   DWORD dwEffect;
 184   HRESULT hr = ::DoDragDrop(m_pData->GetInterface(),
 185                             m_pIDropSource,
 186                             bAllowMove ? DROPEFFECT_COPY | DROPEFFECT_MOVE
 187                                        : DROPEFFECT_COPY,
 188                             &dwEffect);
 189
 190   if ( hr == DRAGDROP_S_CANCEL ) {
 191     return Cancel;
 192   }
 193   else if ( hr == DRAGDROP_S_DROP ) {
 194     if ( dwEffect & DROPEFFECT_COPY ) {
 195       return Copy;
 196     }
 197     else if ( dwEffect & DROPEFFECT_MOVE ) {
 198       // consistency check: normally, we shouldn't get "move" at all
 199       // here if !bAllowMove, but in practice it does happen quite often
 200       if ( bAllowMove )
 201         return Move;
 202       else
 203         return Copy;
 204     }
 205     else {
 206       // not copy or move
 207       return None;
 208     }
 209   }
 210   else {
 211     if ( FAILED(hr) ) {
 212       wxLogApiError("DoDragDrop", hr);
 213       wxLogError("Drag & drop operation failed.");
 214     }
 215     else {
 216       wxLogDebug("Unexpected success return code %08lx from DoDragDrop.", hr);
 217     }
 218
 219     return Error;
 220   }
 221 }
 222
 223 // Name    : wxDropSource::GiveFeedback
 224 // Purpose : visually inform the user about d&d operation state
 225 // Returns : bool: true if we do all ourselves or false for default feedback
 226 // Params  : [in] DragResult effect - what would happen if we dropped now
 227 //           [in] bool bScrolling   - true if target is scrolling
 228 // Notes   : here we just leave this stuff for default implementation
 229 bool wxDropSource::GiveFeedback(DragResult effect, bool bScrolling)
 230 {
 231   return false;
 232 }
 233
 234 #endif  //USE_DRAG_AND_DROP