src/msw/ole/droptgt.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/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 // For compilers that support precompilation, includes "wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #if defined(__BORLANDC__)
  24     #pragma hdrstop
  25 #endif
  26
  27 #if wxUSE_OLE && wxUSE_DRAG_AND_DROP
  28
  29 #ifndef WX_PRECOMP
  30     #include "wx/msw/wrapwin.h"
  31     #include "wx/log.h"
  32 #endif
  33
  34 #include "wx/msw/private.h"
  35
  36 #ifdef __WXWINCE__
  37     #include <winreg.h>
  38     #include <ole2.h>
  39 #endif
  40
  41 #ifdef __WIN32__
  42     #if !defined(__GNUWIN32__) || wxUSE_NORLANDER_HEADERS
  43         #include <shlobj.h>            // for DROPFILES structure
  44     #endif
  45 #else
  46     #include <shellapi.h>
  47 #endif
  48
  49 #include "wx/dnd.h"
  50
  51 #include "wx/msw/ole/oleutils.h"
  52
  53 // ----------------------------------------------------------------------------
  54 // IDropTarget interface: forward all interesting things to wxDropTarget
  55 // (the name is unfortunate, but wx_I_DropTarget is not at all the same thing
  56 //  as wxDropTarget which is 'public' class, while this one is private)
  57 // ----------------------------------------------------------------------------
  58
  59 class wxIDropTarget : public IDropTarget
  60 {
  61 public:
  62     wxIDropTarget(wxDropTarget *p);
  63     virtual ~wxIDropTarget();
  64
  65     // accessors for wxDropTarget
  66     void SetHwnd(HWND hwnd) { m_hwnd = hwnd; }
  67
  68     // IDropTarget methods
  69     STDMETHODIMP DragEnter(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  70     STDMETHODIMP DragOver(DWORD, POINTL, LPDWORD);
  71     STDMETHODIMP DragLeave();
  72     STDMETHODIMP Drop(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  73
  74     DECLARE_IUNKNOWN_METHODS;
  75
  76 protected:
  77     IDataObject  *m_pIDataObject; // !NULL between DragEnter and DragLeave/Drop
  78     wxDropTarget *m_pTarget;      // the real target (we're just a proxy)
  79
  80     HWND          m_hwnd;         // window we're associated with
  81
  82     // get default drop effect for given keyboard flags
  83     static inline DWORD GetDropEffect(DWORD flags, wxDragResult defaultAction);
  84
  85     DECLARE_NO_COPY_CLASS(wxIDropTarget)
  86 };
  87
  88 // ----------------------------------------------------------------------------
  89 // private functions
  90 // ----------------------------------------------------------------------------
  91
  92 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect);
  93 static DWORD ConvertDragResultToEffect(wxDragResult result);
  94
  95 // ============================================================================
  96 // wxIDropTarget implementation
  97 // ============================================================================
  98
  99 // Name    : static wxIDropTarget::GetDropEffect
 100 // Purpose : determine the drop operation from keyboard/mouse state.
 101 // Returns : DWORD combined from DROPEFFECT_xxx constants
 102 // Params  : [in] DWORD flags       kbd & mouse flags as passed to
 103 //                                  IDropTarget methods
 104 // Notes   : We do "move" normally and "copy" if <Ctrl> is pressed,
 105 //           which is the standard behaviour (currently there is no
 106 //           way to redefine it)
 107 DWORD wxIDropTarget::GetDropEffect(DWORD flags, wxDragResult defaultAction)
 108 {
 109   if (defaultAction == wxDragCopy)
 110     return flags & MK_SHIFT ? DROPEFFECT_MOVE : DROPEFFECT_COPY;
 111   return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
 112 }
 113
 114 wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
 115 {
 116   m_pTarget      = pTarget;
 117   m_pIDataObject = NULL;
 118 }
 119
 120 wxIDropTarget::~wxIDropTarget()
 121 {
 122 }
 123
 124 BEGIN_IID_TABLE(wxIDropTarget)
 125   ADD_IID(Unknown)
 126   ADD_IID(DropTarget)
 127 END_IID_TABLE;
 128
 129 IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
 130
 131 // Name    : wxIDropTarget::DragEnter
 132 // Purpose : Called when the mouse enters the window (dragging something)
 133 // Returns : S_OK
 134 // Params  : [in] IDataObject *pIDataSource : source data
 135 //           [in] DWORD        grfKeyState  : kbd & mouse state
 136 //           [in] POINTL       pt           : mouse coordinates
 137 //           [out]DWORD       *pdwEffect    : effect flag
 138 // Notes   :
 139 STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 140                                       DWORD        grfKeyState,
 141                                       POINTL       pt,
 142                                       DWORD       *pdwEffect)
 143 {
 144     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
 145
 146     wxASSERT_MSG( m_pIDataObject == NULL,
 147                   _T("drop target must have data object") );
 148
 149     // show the list of formats supported by the source data object for the
 150     // debugging purposes, this is quite useful sometimes - please don't remove
 151 #if 0
 152     IEnumFORMATETC *penumFmt;
 153     if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
 154     {
 155         FORMATETC fmt;
 156         while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
 157         {
 158             wxLogDebug(_T("Drop source supports format %s"),
 159                        wxDataObject::GetFormatName(fmt.cfFormat));
 160         }
 161
 162         penumFmt->Release();
 163     }
 164     else
 165     {
 166         wxLogLastError(_T("IDataObject::EnumFormatEtc"));
 167     }
 168 #endif // 0
 169
 170     if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
 171         // we don't accept this kind of data
 172         *pdwEffect = DROPEFFECT_NONE;
 173
 174         return S_OK;
 175     }
 176
 177     // get hold of the data object
 178     m_pIDataObject = pIDataSource;
 179     m_pIDataObject->AddRef();
 180
 181     // we need client coordinates to pass to wxWin functions
 182     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 183     {
 184         wxLogLastError(wxT("ScreenToClient"));
 185     }
 186
 187     // give some visual feedback
 188     *pdwEffect = ConvertDragResultToEffect(
 189         m_pTarget->OnEnter(pt.x, pt.y, ConvertDragEffectToResult(
 190             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()))
 191                     )
 192                  );
 193
 194     return S_OK;
 195 }
 196
 197 // Name    : wxIDropTarget::DragOver
 198 // Purpose : Indicates that the mouse was moved inside the window represented
 199 //           by this drop target.
 200 // Returns : S_OK
 201 // Params  : [in] DWORD   grfKeyState     kbd & mouse state
 202 //           [in] POINTL  pt              mouse coordinates
 203 //           [out]LPDWORD pdwEffect       effect flag
 204 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 205 //           very efficient.
 206 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 207                                      POINTL  pt,
 208                                      LPDWORD pdwEffect)
 209 {
 210     // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 211
 212     wxDragResult result;
 213     if ( m_pIDataObject ) {
 214         result = ConvertDragEffectToResult(
 215             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()));
 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 occurred?
 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(
 288             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()));
 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     // FIXME
 333     // RegisterDragDrop not available on Windows CE >= 400?
 334     // Or maybe we can dynamically load them from ceshell.dll
 335     // or similar.
 336 #if defined(__WXWINCE__) && _WIN32_WCE >= 400
 337     wxUnusedVar(hwnd);
 338     return false;
 339 #else
 340     HRESULT hr;
 341
 342     // May exist in later WinCE versions
 343 #ifndef __WXWINCE__
 344     hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 345     if ( FAILED(hr) ) {
 346         wxLogApiError(wxT("CoLockObjectExternal"), hr);
 347         return false;
 348     }
 349 #endif
 350
 351     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 352     if ( FAILED(hr) ) {
 353     // May exist in later WinCE versions
 354 #ifndef __WXWINCE__
 355         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 356 #endif
 357         wxLogApiError(wxT("RegisterDragDrop"), hr);
 358         return false;
 359     }
 360
 361     // we will need the window handle for coords transformation later
 362     m_pIDropTarget->SetHwnd((HWND)hwnd);
 363
 364     return true;
 365 #endif
 366 }
 367
 368 void wxDropTarget::Revoke(WXHWND hwnd)
 369 {
 370 #if defined(__WXWINCE__) && _WIN32_WCE >= 400
 371     // Not available, see note above
 372     wxUnusedVar(hwnd);
 373 #else
 374     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 375
 376     if ( FAILED(hr) ) {
 377         wxLogApiError(wxT("RevokeDragDrop"), hr);
 378     }
 379
 380     // May exist in later WinCE versions
 381 #ifndef __WXWINCE__
 382     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 383 #endif
 384
 385     m_pIDropTarget->SetHwnd(0);
 386 #endif
 387 }
 388
 389 // ----------------------------------------------------------------------------
 390 // base class pure virtuals
 391 // ----------------------------------------------------------------------------
 392
 393 // OnDrop() is called only if we previously returned true from
 394 // IsAcceptedData(), so no need to check anything here
 395 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 396 {
 397     return true;
 398 }
 399
 400 // copy the data from the data source to the target data object
 401 bool wxDropTarget::GetData()
 402 {
 403     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 404     if ( format == wxDF_INVALID ) {
 405         // this is strange because IsAcceptedData() succeeded previously!
 406         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 407
 408         return false;
 409     }
 410
 411     STGMEDIUM stm;
 412     FORMATETC fmtMemory;
 413     fmtMemory.cfFormat  = format;
 414     fmtMemory.ptd       = NULL;
 415     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 416     fmtMemory.lindex    = -1;
 417     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 418
 419     bool rc = false;
 420
 421     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 422     if ( SUCCEEDED(hr) ) {
 423         IDataObject *dataObject = m_dataObject->GetInterface();
 424
 425         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 426         if ( SUCCEEDED(hr) ) {
 427             rc = true;
 428         }
 429         else {
 430             wxLogApiError(wxT("IDataObject::SetData()"), hr);
 431         }
 432     }
 433     else {
 434         wxLogApiError(wxT("IDataObject::GetData()"), hr);
 435     }
 436
 437     return rc;
 438 }
 439
 440 // ----------------------------------------------------------------------------
 441 // callbacks used by wxIDropTarget
 442 // ----------------------------------------------------------------------------
 443
 444 // we need a data source, so wxIDropTarget gives it to us using this function
 445 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 446 {
 447     m_pIDataSource = pIDataSource;
 448 }
 449
 450 // determine if we accept data of this type
 451 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 452 {
 453     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 454 }
 455
 456 // ----------------------------------------------------------------------------
 457 // helper functions
 458 // ----------------------------------------------------------------------------
 459
 460 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 461 {
 462     // this strucutre describes a data of any type (first field will be
 463     // changing) being passed through global memory block.
 464     static FORMATETC s_fmtMemory = {
 465         0,
 466         NULL,
 467         DVASPECT_CONTENT,
 468         -1,
 469         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 470     };
 471
 472     // get the list of supported formats
 473     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 474     wxDataFormat format;
 475     wxDataFormat *formats;
 476     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 477
 478     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 479
 480     // cycle through all supported formats
 481     size_t n;
 482     for ( n = 0; n < nFormats; n++ ) {
 483         s_fmtMemory.cfFormat = formats[n];
 484
 485         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 486         //     for file drag and drop (format == CF_HDROP)
 487         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 488             format = formats[n];
 489
 490             break;
 491         }
 492     }
 493
 494     if ( formats != &format ) {
 495         // free memory if we allocated it
 496         delete [] formats;
 497     }
 498
 499     return n < nFormats ? format : wxFormatInvalid;
 500 }
 501
 502 // ----------------------------------------------------------------------------
 503 // private functions
 504 // ----------------------------------------------------------------------------
 505
 506 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 507 {
 508     switch ( dwEffect ) {
 509         case DROPEFFECT_COPY:
 510             return wxDragCopy;
 511
 512         case DROPEFFECT_LINK:
 513             return wxDragLink;
 514
 515         case DROPEFFECT_MOVE:
 516             return wxDragMove;
 517
 518         default:
 519             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 520             // fall through
 521
 522         case DROPEFFECT_NONE:
 523             return wxDragNone;
 524     }
 525 }
 526
 527 static DWORD ConvertDragResultToEffect(wxDragResult result)
 528 {
 529     switch ( result ) {
 530         case wxDragCopy:
 531             return DROPEFFECT_COPY;
 532
 533         case wxDragLink:
 534             return DROPEFFECT_LINK;
 535
 536         case wxDragMove:
 537             return DROPEFFECT_MOVE;
 538
 539         default:
 540             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 541             // fall through
 542
 543         case wxDragNone:
 544             return DROPEFFECT_NONE;
 545     }
 546 }
 547
 548 #endif // wxUSE_OLE && wxUSE_DRAG_AND_DROP