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 licence
  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     DECLARE_NO_COPY_CLASS(wxIDropTarget)
  90 };
  91
  92 // ----------------------------------------------------------------------------
  93 // private functions
  94 // ----------------------------------------------------------------------------
  95
  96 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect);
  97 static DWORD ConvertDragResultToEffect(wxDragResult result);
  98
  99 // ============================================================================
 100 // wxIDropTarget implementation
 101 // ============================================================================
 102
 103 // Name    : static wxIDropTarget::GetDropEffect
 104 // Purpose : determine the drop operation from keyboard/mouse state.
 105 // Returns : DWORD combined from DROPEFFECT_xxx constants
 106 // Params  : [in] DWORD flags       kbd & mouse flags as passed to
 107 //                                  IDropTarget methods
 108 // Notes   : We do "move" normally and "copy" if <Ctrl> is pressed,
 109 //           which is the standard behaviour (currently there is no
 110 //           way to redefine it)
 111 DWORD wxIDropTarget::GetDropEffect(DWORD flags)
 112 {
 113   return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
 114 }
 115
 116 wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
 117 {
 118   m_pTarget      = pTarget;
 119   m_pIDataObject = NULL;
 120 }
 121
 122 wxIDropTarget::~wxIDropTarget()
 123 {
 124 }
 125
 126 BEGIN_IID_TABLE(wxIDropTarget)
 127   ADD_IID(Unknown)
 128   ADD_IID(DropTarget)
 129 END_IID_TABLE;
 130
 131 IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
 132
 133 // Name    : wxIDropTarget::DragEnter
 134 // Purpose : Called when the mouse enters the window (dragging something)
 135 // Returns : S_OK
 136 // Params  : [in] IDataObject *pIDataSource : source data
 137 //           [in] DWORD        grfKeyState  : kbd & mouse state
 138 //           [in] POINTL       pt           : mouse coordinates
 139 //           [out]DWORD       *pdwEffect    : effect flag
 140 // Notes   :
 141 STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 142                                       DWORD        grfKeyState,
 143                                       POINTL       pt,
 144                                       DWORD       *pdwEffect)
 145 {
 146     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
 147
 148     wxASSERT_MSG( m_pIDataObject == NULL,
 149                   _T("drop target must have data object") );
 150
 151     // show the list of formats supported by the source data object for the
 152     // debugging purposes, this is quite useful sometimes - please don't remove
 153 #if 0
 154     IEnumFORMATETC *penumFmt;
 155     if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
 156     {
 157         FORMATETC fmt;
 158         while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
 159         {
 160             wxLogDebug(_T("Drop source supports format %s"),
 161                        wxDataObject::GetFormatName(fmt.cfFormat));
 162         }
 163
 164         penumFmt->Release();
 165     }
 166     else
 167     {
 168         wxLogLastError(_T("IDataObject::EnumFormatEtc"));
 169     }
 170 #endif // 0
 171
 172     if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
 173         // we don't accept this kind of data
 174         *pdwEffect = DROPEFFECT_NONE;
 175
 176         return S_OK;
 177     }
 178
 179     // get hold of the data object
 180     m_pIDataObject = pIDataSource;
 181     m_pIDataObject->AddRef();
 182
 183     // we need client coordinates to pass to wxWin functions
 184     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 185     {
 186         wxLogLastError(wxT("ScreenToClient"));
 187     }
 188
 189     // give some visual feedback
 190     *pdwEffect = ConvertDragResultToEffect(
 191                     m_pTarget->OnEnter(pt.x, pt.y,
 192                         ConvertDragEffectToResult(GetDropEffect(grfKeyState))
 193                     )
 194                  );
 195
 196     return S_OK;
 197 }
 198
 199 // Name    : wxIDropTarget::DragOver
 200 // Purpose : Indicates that the mouse was moved inside the window represented
 201 //           by this drop target.
 202 // Returns : S_OK
 203 // Params  : [in] DWORD   grfKeyState     kbd & mouse state
 204 //           [in] POINTL  pt              mouse coordinates
 205 //           [out]LPDWORD pdwEffect       effect flag
 206 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 207 //           very efficient.
 208 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 209                                      POINTL  pt,
 210                                      LPDWORD pdwEffect)
 211 {
 212     // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 213
 214     wxDragResult result;
 215     if ( m_pIDataObject ) {
 216         result = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 217     }
 218     else {
 219         // can't accept data anyhow normally
 220         result = wxDragNone;
 221     }
 222
 223     // we need client coordinates to pass to wxWin functions
 224     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 225     {
 226         wxLogLastError(wxT("ScreenToClient"));
 227     }
 228
 229     *pdwEffect = ConvertDragResultToEffect(
 230                     m_pTarget->OnDragOver(pt.x, pt.y, result)
 231                  );
 232
 233     return S_OK;
 234 }
 235
 236 // Name    : wxIDropTarget::DragLeave
 237 // Purpose : Informs the drop target that the operation has left its window.
 238 // Returns : S_OK
 239 // Notes   : good place to do any clean-up
 240 STDMETHODIMP wxIDropTarget::DragLeave()
 241 {
 242   wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));
 243
 244   // remove the UI feedback
 245   m_pTarget->OnLeave();
 246
 247   // release the held object
 248   RELEASE_AND_NULL(m_pIDataObject);
 249
 250   return S_OK;
 251 }
 252
 253 // Name    : wxIDropTarget::Drop
 254 // Purpose : Instructs the drop target to paste data that was just now
 255 //           dropped on it.
 256 // Returns : S_OK
 257 // Params  : [in] IDataObject *pIDataSource     the data to paste
 258 //           [in] DWORD        grfKeyState      kbd & mouse state
 259 //           [in] POINTL       pt               where the drop occured?
 260 //           [ouy]DWORD       *pdwEffect        operation effect
 261 // Notes   :
 262 STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 263                                  DWORD        grfKeyState,
 264                                  POINTL       pt,
 265                                  DWORD       *pdwEffect)
 266 {
 267     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
 268
 269     // TODO I don't know why there is this parameter, but so far I assume
 270     //      that it's the same we've already got in DragEnter
 271     wxASSERT( m_pIDataObject == pIDataSource );
 272
 273     // by default, nothing happens
 274     *pdwEffect = DROPEFFECT_NONE;
 275
 276     // we need client coordinates to pass to wxWin functions
 277     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 278     {
 279         wxLogLastError(wxT("ScreenToClient"));
 280     }
 281
 282     // first ask the drop target if it wants data
 283     if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
 284         // it does, so give it the data source
 285         m_pTarget->SetDataSource(pIDataSource);
 286
 287         // and now it has the data
 288         wxDragResult rc = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 289         rc = m_pTarget->OnData(pt.x, pt.y, rc);
 290         if ( wxIsDragResultOk(rc) ) {
 291             // operation succeeded
 292             *pdwEffect = ConvertDragResultToEffect(rc);
 293         }
 294         //else: *pdwEffect is already DROPEFFECT_NONE
 295     }
 296     //else: OnDrop() returned FALSE, no need to copy data
 297
 298     // release the held object
 299     RELEASE_AND_NULL(m_pIDataObject);
 300
 301     return S_OK;
 302 }
 303
 304 // ============================================================================
 305 // wxDropTarget implementation
 306 // ============================================================================
 307
 308 // ----------------------------------------------------------------------------
 309 // ctor/dtor
 310 // ----------------------------------------------------------------------------
 311
 312 wxDropTarget::wxDropTarget(wxDataObject *dataObj)
 313             : wxDropTargetBase(dataObj)
 314 {
 315     // create an IDropTarget implementation which will notify us about d&d
 316     // operations.
 317     m_pIDropTarget = new wxIDropTarget(this);
 318     m_pIDropTarget->AddRef();
 319 }
 320
 321 wxDropTarget::~wxDropTarget()
 322 {
 323     ReleaseInterface(m_pIDropTarget);
 324 }
 325
 326 // ----------------------------------------------------------------------------
 327 // [un]register drop handler
 328 // ----------------------------------------------------------------------------
 329
 330 bool wxDropTarget::Register(WXHWND hwnd)
 331 {
 332     HRESULT hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 333     if ( FAILED(hr) ) {
 334         wxLogApiError(wxT("CoLockObjectExternal"), hr);
 335         return FALSE;
 336     }
 337
 338     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 339     if ( FAILED(hr) ) {
 340         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 341
 342         wxLogApiError(wxT("RegisterDragDrop"), hr);
 343         return FALSE;
 344     }
 345
 346     // we will need the window handle for coords transformation later
 347     m_pIDropTarget->SetHwnd((HWND)hwnd);
 348
 349     return TRUE;
 350 }
 351
 352 void wxDropTarget::Revoke(WXHWND hwnd)
 353 {
 354     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 355
 356     if ( FAILED(hr) ) {
 357         wxLogApiError(wxT("RevokeDragDrop"), hr);
 358     }
 359
 360     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 361
 362     m_pIDropTarget->SetHwnd(0);
 363 }
 364
 365 // ----------------------------------------------------------------------------
 366 // base class pure virtuals
 367 // ----------------------------------------------------------------------------
 368
 369 // OnDrop() is called only if we previously returned TRUE from
 370 // IsAcceptedData(), so no need to check anything here
 371 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 372 {
 373     return TRUE;
 374 }
 375
 376 // copy the data from the data source to the target data object
 377 bool wxDropTarget::GetData()
 378 {
 379     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 380     if ( format == wxDF_INVALID ) {
 381         // this is strange because IsAcceptedData() succeeded previously!
 382         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 383
 384         return FALSE;
 385     }
 386
 387     STGMEDIUM stm;
 388     FORMATETC fmtMemory;
 389     fmtMemory.cfFormat  = format;
 390     fmtMemory.ptd       = NULL;
 391     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 392     fmtMemory.lindex    = -1;
 393     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 394
 395     bool rc = FALSE;
 396
 397     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 398     if ( SUCCEEDED(hr) ) {
 399         IDataObject *dataObject = m_dataObject->GetInterface();
 400
 401         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 402         if ( SUCCEEDED(hr) ) {
 403             rc = TRUE;
 404         }
 405         else {
 406             wxLogApiError(wxT("IDataObject::SetData()"), hr);
 407         }
 408     }
 409     else {
 410         wxLogApiError(wxT("IDataObject::GetData()"), hr);
 411     }
 412
 413     return rc;
 414 }
 415
 416 // ----------------------------------------------------------------------------
 417 // callbacks used by wxIDropTarget
 418 // ----------------------------------------------------------------------------
 419
 420 // we need a data source, so wxIDropTarget gives it to us using this function
 421 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 422 {
 423     m_pIDataSource = pIDataSource;
 424 }
 425
 426 // determine if we accept data of this type
 427 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 428 {
 429     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 430 }
 431
 432 // ----------------------------------------------------------------------------
 433 // helper functions
 434 // ----------------------------------------------------------------------------
 435
 436 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 437 {
 438     // this strucutre describes a data of any type (first field will be
 439     // changing) being passed through global memory block.
 440     static FORMATETC s_fmtMemory = {
 441         0,
 442         NULL,
 443         DVASPECT_CONTENT,
 444         -1,
 445         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 446     };
 447
 448     // get the list of supported formats
 449     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 450     wxDataFormat format;
 451     wxDataFormat *formats;
 452     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 453
 454     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 455
 456     // cycle through all supported formats
 457     size_t n;
 458     for ( n = 0; n < nFormats; n++ ) {
 459         s_fmtMemory.cfFormat = formats[n];
 460
 461         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 462         //     for file drag and drop (format == CF_HDROP)
 463         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 464             format = formats[n];
 465
 466             break;
 467         }
 468     }
 469
 470     if ( formats != &format ) {
 471         // free memory if we allocated it
 472         delete [] formats;
 473     }
 474
 475     return n < nFormats ? format : wxFormatInvalid;
 476 }
 477
 478 // ----------------------------------------------------------------------------
 479 // private functions
 480 // ----------------------------------------------------------------------------
 481
 482 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 483 {
 484     switch ( dwEffect ) {
 485         case DROPEFFECT_COPY:
 486             return wxDragCopy;
 487
 488         case DROPEFFECT_LINK:
 489             return wxDragLink;
 490
 491         case DROPEFFECT_MOVE:
 492             return wxDragMove;
 493
 494         default:
 495             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 496             // fall through
 497
 498         case DROPEFFECT_NONE:
 499             return wxDragNone;
 500     }
 501 }
 502
 503 static DWORD ConvertDragResultToEffect(wxDragResult result)
 504 {
 505     switch ( result ) {
 506         case wxDragCopy:
 507             return DROPEFFECT_COPY;
 508
 509         case wxDragLink:
 510             return DROPEFFECT_LINK;
 511
 512         case wxDragMove:
 513             return DROPEFFECT_MOVE;
 514
 515         default:
 516             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 517             // fall through
 518
 519         case wxDragNone:
 520             return DROPEFFECT_NONE;
 521     }
 522 }
 523
 524 #endif
 525  // wxUSE_DRAG_AND_DROP