src/msw/ole/droptgt.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        ole/droptgt.cpp
   3 // Purpose:     wxDropTarget implementation
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:
   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 "droptgt.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_OLE && wxUSE_DRAG_AND_DROP
  34
  35 #include "wx/log.h"
  36
  37 #ifdef __WIN32__
  38     #if !defined(__GNUWIN32__) || wxUSE_NORLANDER_HEADERS
  39         #if wxCHECK_W32API_VERSION( 1, 0 )
  40             #include <windows.h>
  41         #endif
  42         #include <shlobj.h>            // for DROPFILES structure
  43     #endif
  44 #else
  45     #include <shellapi.h>
  46 #endif
  47
  48 #include "wx/dnd.h"
  49
  50 #ifndef __WIN32__
  51     #include <ole2.h>
  52     #include <olestd.h>
  53 #endif
  54
  55 #include "wx/msw/ole/oleutils.h"
  56
  57 // ----------------------------------------------------------------------------
  58 // IDropTarget interface: forward all interesting things to wxDropTarget
  59 // (the name is unfortunate, but wx_I_DropTarget is not at all the same thing
  60 //  as wxDropTarget which is 'public' class, while this one is private)
  61 // ----------------------------------------------------------------------------
  62
  63 class wxIDropTarget : public IDropTarget
  64 {
  65 public:
  66     wxIDropTarget(wxDropTarget *p);
  67     virtual ~wxIDropTarget();
  68
  69     // accessors for wxDropTarget
  70     void SetHwnd(HWND hwnd) { m_hwnd = hwnd; }
  71
  72     // IDropTarget methods
  73     STDMETHODIMP DragEnter(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  74     STDMETHODIMP DragOver(DWORD, POINTL, LPDWORD);
  75     STDMETHODIMP DragLeave();
  76     STDMETHODIMP Drop(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  77
  78     DECLARE_IUNKNOWN_METHODS;
  79
  80 protected:
  81     IDataObject  *m_pIDataObject; // !NULL between DragEnter and DragLeave/Drop
  82     wxDropTarget *m_pTarget;      // the real target (we're just a proxy)
  83
  84     HWND          m_hwnd;         // window we're associated with
  85
  86     // get default drop effect for given keyboard flags
  87     static inline DWORD GetDropEffect(DWORD flags);
  88 };
  89
  90 // ----------------------------------------------------------------------------
  91 // private functions
  92 // ----------------------------------------------------------------------------
  93
  94 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect);
  95 static DWORD ConvertDragResultToEffect(wxDragResult result);
  96
  97 // ============================================================================
  98 // wxIDropTarget implementation
  99 // ============================================================================
 100
 101 // Name    : static wxIDropTarget::GetDropEffect
 102 // Purpose : determine the drop operation from keyboard/mouse state.
 103 // Returns : DWORD combined from DROPEFFECT_xxx constants
 104 // Params  : [in] DWORD flags       kbd & mouse flags as passed to
 105 //                                  IDropTarget methods
 106 // Notes   : We do "move" normally and "copy" if <Ctrl> is pressed,
 107 //           which is the standard behaviour (currently there is no
 108 //           way to redefine it)
 109 DWORD wxIDropTarget::GetDropEffect(DWORD flags)
 110 {
 111   return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
 112 }
 113
 114 wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
 115 {
 116   m_cRef         = 0;
 117   m_pTarget      = pTarget;
 118   m_pIDataObject = NULL;
 119 }
 120
 121 wxIDropTarget::~wxIDropTarget()
 122 {
 123 }
 124
 125 BEGIN_IID_TABLE(wxIDropTarget)
 126   ADD_IID(Unknown)
 127   ADD_IID(DropTarget)
 128 END_IID_TABLE;
 129
 130 IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
 131
 132 // Name    : wxIDropTarget::DragEnter
 133 // Purpose : Called when the mouse enters the window (dragging something)
 134 // Returns : S_OK
 135 // Params  : [in] IDataObject *pIDataSource : source data
 136 //           [in] DWORD        grfKeyState  : kbd & mouse state
 137 //           [in] POINTL       pt           : mouse coordinates
 138 //           [out]DWORD       *pdwEffect    : effect flag
 139 // Notes   :
 140 STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 141                                       DWORD        grfKeyState,
 142                                       POINTL       pt,
 143                                       DWORD       *pdwEffect)
 144 {
 145     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
 146
 147     wxASSERT_MSG( m_pIDataObject == NULL,
 148                   _T("drop target must have data object") );
 149
 150     // show the list of formats supported by the source data object for the
 151     // debugging purposes, this is quite useful sometimes - please don't remove
 152 #if 0
 153     IEnumFORMATETC *penumFmt;
 154     if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
 155     {
 156         FORMATETC fmt;
 157         while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
 158         {
 159             wxLogDebug(_T("Drop source supports format %s"),
 160                        wxDataObject::GetFormatName(fmt.cfFormat));
 161         }
 162
 163         penumFmt->Release();
 164     }
 165     else
 166     {
 167         wxLogLastError(_T("IDataObject::EnumFormatEtc"));
 168     }
 169 #endif // 0
 170
 171     if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
 172         // we don't accept this kind of data
 173         *pdwEffect = DROPEFFECT_NONE;
 174
 175         return S_OK;
 176     }
 177
 178     // get hold of the data object
 179     m_pIDataObject = pIDataSource;
 180     m_pIDataObject->AddRef();
 181
 182     // we need client coordinates to pass to wxWin functions
 183     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 184     {
 185         wxLogLastError(wxT("ScreenToClient"));
 186     }
 187
 188     // give some visual feedback
 189     *pdwEffect = ConvertDragResultToEffect(
 190                     m_pTarget->OnEnter(pt.x, pt.y,
 191                         ConvertDragEffectToResult(GetDropEffect(grfKeyState))
 192                     )
 193                  );
 194
 195     return S_OK;
 196 }
 197
 198 // Name    : wxIDropTarget::DragOver
 199 // Purpose : Indicates that the mouse was moved inside the window represented
 200 //           by this drop target.
 201 // Returns : S_OK
 202 // Params  : [in] DWORD   grfKeyState     kbd & mouse state
 203 //           [in] POINTL  pt              mouse coordinates
 204 //           [out]LPDWORD pdwEffect       effect flag
 205 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 206 //           very efficient.
 207 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 208                                      POINTL  pt,
 209                                      LPDWORD pdwEffect)
 210 {
 211     // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 212
 213     wxDragResult result;
 214     if ( m_pIDataObject ) {
 215         result = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 216     }
 217     else {
 218         // can't accept data anyhow normally
 219         result = wxDragNone;
 220     }
 221
 222     // we need client coordinates to pass to wxWin functions
 223     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 224     {
 225         wxLogLastError(wxT("ScreenToClient"));
 226     }
 227
 228     *pdwEffect = ConvertDragResultToEffect(
 229                     m_pTarget->OnDragOver(pt.x, pt.y, result)
 230                  );
 231
 232     return S_OK;
 233 }
 234
 235 // Name    : wxIDropTarget::DragLeave
 236 // Purpose : Informs the drop target that the operation has left its window.
 237 // Returns : S_OK
 238 // Notes   : good place to do any clean-up
 239 STDMETHODIMP wxIDropTarget::DragLeave()
 240 {
 241   wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));
 242
 243   // remove the UI feedback
 244   m_pTarget->OnLeave();
 245
 246   // release the held object
 247   RELEASE_AND_NULL(m_pIDataObject);
 248
 249   return S_OK;
 250 }
 251
 252 // Name    : wxIDropTarget::Drop
 253 // Purpose : Instructs the drop target to paste data that was just now
 254 //           dropped on it.
 255 // Returns : S_OK
 256 // Params  : [in] IDataObject *pIDataSource     the data to paste
 257 //           [in] DWORD        grfKeyState      kbd & mouse state
 258 //           [in] POINTL       pt               where the drop occured?
 259 //           [ouy]DWORD       *pdwEffect        operation effect
 260 // Notes   :
 261 STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 262                                  DWORD        grfKeyState,
 263                                  POINTL       pt,
 264                                  DWORD       *pdwEffect)
 265 {
 266     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
 267
 268     // TODO I don't know why there is this parameter, but so far I assume
 269     //      that it's the same we've already got in DragEnter
 270     wxASSERT( m_pIDataObject == pIDataSource );
 271
 272     // by default, nothing happens
 273     *pdwEffect = DROPEFFECT_NONE;
 274
 275     // we need client coordinates to pass to wxWin functions
 276     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 277     {
 278         wxLogLastError(wxT("ScreenToClient"));
 279     }
 280
 281     // first ask the drop target if it wants data
 282     if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
 283         // it does, so give it the data source
 284         m_pTarget->SetDataSource(pIDataSource);
 285
 286         // and now it has the data
 287         wxDragResult rc = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 288         rc = m_pTarget->OnData(pt.x, pt.y, rc);
 289         if ( wxIsDragResultOk(rc) ) {
 290             // operation succeeded
 291             *pdwEffect = ConvertDragResultToEffect(rc);
 292         }
 293         //else: *pdwEffect is already DROPEFFECT_NONE
 294     }
 295     //else: OnDrop() returned FALSE, no need to copy data
 296
 297     // release the held object
 298     RELEASE_AND_NULL(m_pIDataObject);
 299
 300     return S_OK;
 301 }
 302
 303 // ============================================================================
 304 // wxDropTarget implementation
 305 // ============================================================================
 306
 307 // ----------------------------------------------------------------------------
 308 // ctor/dtor
 309 // ----------------------------------------------------------------------------
 310
 311 wxDropTarget::wxDropTarget(wxDataObject *dataObj)
 312             : wxDropTargetBase(dataObj)
 313 {
 314     // create an IDropTarget implementation which will notify us about d&d
 315     // operations.
 316     m_pIDropTarget = new wxIDropTarget(this);
 317     m_pIDropTarget->AddRef();
 318 }
 319
 320 wxDropTarget::~wxDropTarget()
 321 {
 322     ReleaseInterface(m_pIDropTarget);
 323 }
 324
 325 // ----------------------------------------------------------------------------
 326 // [un]register drop handler
 327 // ----------------------------------------------------------------------------
 328
 329 bool wxDropTarget::Register(WXHWND hwnd)
 330 {
 331     HRESULT hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 332     if ( FAILED(hr) ) {
 333         wxLogApiError(wxT("CoLockObjectExternal"), hr);
 334         return FALSE;
 335     }
 336
 337     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 338     if ( FAILED(hr) ) {
 339         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 340
 341         wxLogApiError(wxT("RegisterDragDrop"), hr);
 342         return FALSE;
 343     }
 344
 345     // we will need the window handle for coords transformation later
 346     m_pIDropTarget->SetHwnd((HWND)hwnd);
 347
 348     return TRUE;
 349 }
 350
 351 void wxDropTarget::Revoke(WXHWND hwnd)
 352 {
 353     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 354
 355     if ( FAILED(hr) ) {
 356         wxLogApiError(wxT("RevokeDragDrop"), hr);
 357     }
 358
 359     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 360
 361     m_pIDropTarget->SetHwnd(0);
 362 }
 363
 364 // ----------------------------------------------------------------------------
 365 // base class pure virtuals
 366 // ----------------------------------------------------------------------------
 367
 368 // OnDrop() is called only if we previously returned TRUE from
 369 // IsAcceptedData(), so no need to check anything here
 370 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 371 {
 372     return TRUE;
 373 }
 374
 375 // copy the data from the data source to the target data object
 376 bool wxDropTarget::GetData()
 377 {
 378     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 379     if ( format == wxDF_INVALID ) {
 380         // this is strange because IsAcceptedData() succeeded previously!
 381         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 382
 383         return FALSE;
 384     }
 385
 386     STGMEDIUM stm;
 387     FORMATETC fmtMemory;
 388     fmtMemory.cfFormat  = format;
 389     fmtMemory.ptd       = NULL;
 390     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 391     fmtMemory.lindex    = -1;
 392     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 393
 394     bool rc = FALSE;
 395
 396     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 397     if ( SUCCEEDED(hr) ) {
 398         IDataObject *dataObject = m_dataObject->GetInterface();
 399
 400         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 401         if ( SUCCEEDED(hr) ) {
 402             rc = TRUE;
 403         }
 404         else {
 405             wxLogApiError(wxT("IDataObject::SetData()"), hr);
 406         }
 407     }
 408     else {
 409         wxLogApiError(wxT("IDataObject::GetData()"), hr);
 410     }
 411
 412     return rc;
 413 }
 414
 415 // ----------------------------------------------------------------------------
 416 // callbacks used by wxIDropTarget
 417 // ----------------------------------------------------------------------------
 418
 419 // we need a data source, so wxIDropTarget gives it to us using this function
 420 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 421 {
 422     m_pIDataSource = pIDataSource;
 423 }
 424
 425 // determine if we accept data of this type
 426 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 427 {
 428     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 429 }
 430
 431 // ----------------------------------------------------------------------------
 432 // helper functions
 433 // ----------------------------------------------------------------------------
 434
 435 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 436 {
 437     // this strucutre describes a data of any type (first field will be
 438     // changing) being passed through global memory block.
 439     static FORMATETC s_fmtMemory = {
 440         0,
 441         NULL,
 442         DVASPECT_CONTENT,
 443         -1,
 444         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 445     };
 446
 447     // get the list of supported formats
 448     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 449     wxDataFormat format;
 450     wxDataFormat *formats;
 451     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 452
 453     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 454
 455     // cycle through all supported formats
 456     size_t n;
 457     for ( n = 0; n < nFormats; n++ ) {
 458         s_fmtMemory.cfFormat = formats[n];
 459
 460         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 461         //     for file drag and drop (format == CF_HDROP)
 462         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 463             format = formats[n];
 464
 465             break;
 466         }
 467     }
 468
 469     if ( formats != &format ) {
 470         // free memory if we allocated it
 471         delete [] formats;
 472     }
 473
 474     return n < nFormats ? format : wxFormatInvalid;
 475 }
 476
 477 // ----------------------------------------------------------------------------
 478 // private functions
 479 // ----------------------------------------------------------------------------
 480
 481 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 482 {
 483     switch ( dwEffect ) {
 484         case DROPEFFECT_COPY:
 485             return wxDragCopy;
 486
 487         case DROPEFFECT_MOVE:
 488             return wxDragMove;
 489
 490         default:
 491             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 492             // fall through
 493
 494         case DROPEFFECT_NONE:
 495             return wxDragNone;
 496     }
 497 }
 498
 499 static DWORD ConvertDragResultToEffect(wxDragResult result)
 500 {
 501     switch ( result ) {
 502         case wxDragCopy:
 503             return DROPEFFECT_COPY;
 504
 505         case wxDragMove:
 506             return DROPEFFECT_MOVE;
 507
 508         default:
 509             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 510             // fall through
 511
 512         case wxDragNone:
 513             return DROPEFFECT_NONE;
 514     }
 515 }
 516
 517 #endif
 518  // wxUSE_DRAG_AND_DROP