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 DWORD GetDropEffect(DWORD flags, wxDragResult defaultAction, DWORD pdwEffect);
  84
  85     wxDECLARE_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 //           [in] wxDragResult defaultAction  the default action of the drop target
 105 //           [in] DWORD pdwEffect             the supported actions of the drop
 106 //                                            source passed to IDropTarget methods
 107 // Notes   : We do "move" normally and "copy" if <Ctrl> is pressed,
 108 //           which is the standard behaviour (currently there is no
 109 //           way to redefine it)
 110 DWORD wxIDropTarget::GetDropEffect(DWORD flags,
 111                                    wxDragResult defaultAction,
 112                                    DWORD pdwEffect)
 113 {
 114     DWORD effectiveAction;
 115     if ( defaultAction == wxDragCopy )
 116         effectiveAction = flags & MK_SHIFT ? DROPEFFECT_MOVE : DROPEFFECT_COPY;
 117     else
 118         effectiveAction = flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
 119
 120     if ( !(effectiveAction & pdwEffect) )
 121     {
 122         // the action is not supported by drag source, fall back to something
 123         // that it does support
 124         if ( pdwEffect & DROPEFFECT_MOVE )
 125             effectiveAction = DROPEFFECT_MOVE;
 126         else if ( pdwEffect & DROPEFFECT_COPY )
 127             effectiveAction = DROPEFFECT_COPY;
 128         else if ( pdwEffect & DROPEFFECT_LINK )
 129             effectiveAction = DROPEFFECT_LINK;
 130         else
 131             effectiveAction = DROPEFFECT_NONE;
 132     }
 133
 134     return effectiveAction;
 135 }
 136
 137 wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
 138 {
 139   m_pTarget      = pTarget;
 140   m_pIDataObject = NULL;
 141 }
 142
 143 wxIDropTarget::~wxIDropTarget()
 144 {
 145 }
 146
 147 BEGIN_IID_TABLE(wxIDropTarget)
 148   ADD_IID(Unknown)
 149   ADD_IID(DropTarget)
 150 END_IID_TABLE;
 151
 152 IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
 153
 154 // Name    : wxIDropTarget::DragEnter
 155 // Purpose : Called when the mouse enters the window (dragging something)
 156 // Returns : S_OK
 157 // Params  : [in]    IDataObject *pIDataSource : source data
 158 //           [in]    DWORD        grfKeyState  : kbd & mouse state
 159 //           [in]    POINTL       pt           : mouse coordinates
 160 //           [in/out]DWORD       *pdwEffect    : effect flag
 161 //                                               In:  Supported effects
 162 //                                               Out: Resulting effect
 163 // Notes   :
 164 STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 165                                       DWORD        grfKeyState,
 166                                       POINTL       pt,
 167                                       DWORD       *pdwEffect)
 168 {
 169     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
 170
 171     wxASSERT_MSG( m_pIDataObject == NULL,
 172                   wxT("drop target must have data object") );
 173
 174     // show the list of formats supported by the source data object for the
 175     // debugging purposes, this is quite useful sometimes - please don't remove
 176 #if 0
 177     IEnumFORMATETC *penumFmt;
 178     if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
 179     {
 180         FORMATETC fmt;
 181         while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
 182         {
 183             wxLogDebug(wxT("Drop source supports format %s"),
 184                        wxDataObject::GetFormatName(fmt.cfFormat));
 185         }
 186
 187         penumFmt->Release();
 188     }
 189     else
 190     {
 191         wxLogLastError(wxT("IDataObject::EnumFormatEtc"));
 192     }
 193 #endif // 0
 194
 195     if ( !m_pTarget->MSWIsAcceptedData(pIDataSource) ) {
 196         // we don't accept this kind of data
 197         *pdwEffect = DROPEFFECT_NONE;
 198
 199         return S_OK;
 200     }
 201
 202     // for use in OnEnter and OnDrag calls
 203     m_pTarget->MSWSetDataSource(pIDataSource);
 204
 205     // get hold of the data object
 206     m_pIDataObject = pIDataSource;
 207     m_pIDataObject->AddRef();
 208
 209     // we need client coordinates to pass to wxWin functions
 210     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 211     {
 212         wxLogLastError(wxT("ScreenToClient"));
 213     }
 214
 215     // give some visual feedback
 216     *pdwEffect = ConvertDragResultToEffect(
 217         m_pTarget->OnEnter(pt.x, pt.y, ConvertDragEffectToResult(
 218             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect))
 219                     )
 220                  );
 221
 222     return S_OK;
 223 }
 224
 225 // Name    : wxIDropTarget::DragOver
 226 // Purpose : Indicates that the mouse was moved inside the window represented
 227 //           by this drop target.
 228 // Returns : S_OK
 229 // Params  : [in]    DWORD   grfKeyState     kbd & mouse state
 230 //           [in]    POINTL  pt              mouse coordinates
 231 //           [in/out]LPDWORD pdwEffect       current effect flag
 232 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 233 //           very efficient.
 234 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 235                                      POINTL  pt,
 236                                      LPDWORD pdwEffect)
 237 {
 238     // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 239
 240     wxDragResult result;
 241     if ( m_pIDataObject ) {
 242         result = ConvertDragEffectToResult(
 243             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect));
 244     }
 245     else {
 246         // can't accept data anyhow normally
 247         result = wxDragNone;
 248     }
 249
 250     if ( result != wxDragNone ) {
 251         // we need client coordinates to pass to wxWin functions
 252         if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 253         {
 254             wxLogLastError(wxT("ScreenToClient"));
 255         }
 256
 257         *pdwEffect = ConvertDragResultToEffect(
 258                         m_pTarget->OnDragOver(pt.x, pt.y, result)
 259                      );
 260     }
 261     else {
 262         *pdwEffect = DROPEFFECT_NONE;
 263     }
 264
 265     return S_OK;
 266 }
 267
 268 // Name    : wxIDropTarget::DragLeave
 269 // Purpose : Informs the drop target that the operation has left its window.
 270 // Returns : S_OK
 271 // Notes   : good place to do any clean-up
 272 STDMETHODIMP wxIDropTarget::DragLeave()
 273 {
 274   wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));
 275
 276   // remove the UI feedback
 277   m_pTarget->OnLeave();
 278
 279   // release the held object
 280   RELEASE_AND_NULL(m_pIDataObject);
 281
 282   return S_OK;
 283 }
 284
 285 // Name    : wxIDropTarget::Drop
 286 // Purpose : Instructs the drop target to paste data that was just now
 287 //           dropped on it.
 288 // Returns : S_OK
 289 // Params  : [in]    IDataObject *pIDataSource     the data to paste
 290 //           [in]    DWORD        grfKeyState      kbd & mouse state
 291 //           [in]    POINTL       pt               where the drop occurred?
 292 //           [in/out]DWORD       *pdwEffect        operation effect
 293 // Notes   :
 294 STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 295                                  DWORD        grfKeyState,
 296                                  POINTL       pt,
 297                                  DWORD       *pdwEffect)
 298 {
 299     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
 300
 301     // TODO I don't know why there is this parameter, but so far I assume
 302     //      that it's the same we've already got in DragEnter
 303     wxASSERT( m_pIDataObject == pIDataSource );
 304
 305     // we need client coordinates to pass to wxWin functions
 306     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 307     {
 308         wxLogLastError(wxT("ScreenToClient"));
 309     }
 310
 311     // first ask the drop target if it wants data
 312     if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
 313         // it does, so give it the data source
 314         m_pTarget->MSWSetDataSource(pIDataSource);
 315
 316         // and now it has the data
 317         wxDragResult rc = ConvertDragEffectToResult(
 318             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect));
 319         rc = m_pTarget->OnData(pt.x, pt.y, rc);
 320         if ( wxIsDragResultOk(rc) ) {
 321             // operation succeeded
 322             *pdwEffect = ConvertDragResultToEffect(rc);
 323         }
 324         else {
 325             *pdwEffect = DROPEFFECT_NONE;
 326         }
 327     }
 328     else {
 329         // OnDrop() returned false, no need to copy data
 330         *pdwEffect = DROPEFFECT_NONE;
 331     }
 332
 333     // release the held object
 334     RELEASE_AND_NULL(m_pIDataObject);
 335
 336     return S_OK;
 337 }
 338
 339 // ============================================================================
 340 // wxDropTarget implementation
 341 // ============================================================================
 342
 343 // ----------------------------------------------------------------------------
 344 // ctor/dtor
 345 // ----------------------------------------------------------------------------
 346
 347 wxDropTarget::wxDropTarget(wxDataObject *dataObj)
 348             : wxDropTargetBase(dataObj)
 349 {
 350     // create an IDropTarget implementation which will notify us about d&d
 351     // operations.
 352     m_pIDropTarget = new wxIDropTarget(this);
 353     m_pIDropTarget->AddRef();
 354 }
 355
 356 wxDropTarget::~wxDropTarget()
 357 {
 358     ReleaseInterface(m_pIDropTarget);
 359 }
 360
 361 // ----------------------------------------------------------------------------
 362 // [un]register drop handler
 363 // ----------------------------------------------------------------------------
 364
 365 bool wxDropTarget::Register(WXHWND hwnd)
 366 {
 367     // FIXME
 368     // RegisterDragDrop not available on Windows CE >= 400?
 369     // Or maybe we can dynamically load them from ceshell.dll
 370     // or similar.
 371 #if defined(__WXWINCE__) && _WIN32_WCE >= 400
 372     wxUnusedVar(hwnd);
 373     return false;
 374 #else
 375     HRESULT hr;
 376
 377     // May exist in later WinCE versions
 378 #ifndef __WXWINCE__
 379     hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 380     if ( FAILED(hr) ) {
 381         wxLogApiError(wxT("CoLockObjectExternal"), hr);
 382         return false;
 383     }
 384 #endif
 385
 386     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 387     if ( FAILED(hr) ) {
 388     // May exist in later WinCE versions
 389 #ifndef __WXWINCE__
 390         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 391 #endif
 392         wxLogApiError(wxT("RegisterDragDrop"), hr);
 393         return false;
 394     }
 395
 396     // we will need the window handle for coords transformation later
 397     m_pIDropTarget->SetHwnd((HWND)hwnd);
 398
 399     return true;
 400 #endif
 401 }
 402
 403 void wxDropTarget::Revoke(WXHWND hwnd)
 404 {
 405 #if defined(__WXWINCE__) && _WIN32_WCE >= 400
 406     // Not available, see note above
 407     wxUnusedVar(hwnd);
 408 #else
 409     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 410
 411     if ( FAILED(hr) ) {
 412         wxLogApiError(wxT("RevokeDragDrop"), hr);
 413     }
 414
 415     // May exist in later WinCE versions
 416 #ifndef __WXWINCE__
 417     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 418 #endif
 419
 420     m_pIDropTarget->SetHwnd(0);
 421 #endif
 422 }
 423
 424 // ----------------------------------------------------------------------------
 425 // base class pure virtuals
 426 // ----------------------------------------------------------------------------
 427
 428 // OnDrop() is called only if we previously returned true from
 429 // IsAcceptedData(), so no need to check anything here
 430 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 431 {
 432     return true;
 433 }
 434
 435 // copy the data from the data source to the target data object
 436 bool wxDropTarget::GetData()
 437 {
 438     wxDataFormat format = MSWGetSupportedFormat(m_pIDataSource);
 439     if ( format == wxDF_INVALID ) {
 440         // this is strange because IsAcceptedData() succeeded previously!
 441         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 442
 443         return false;
 444     }
 445
 446     STGMEDIUM stm;
 447     FORMATETC fmtMemory;
 448     fmtMemory.cfFormat  = format;
 449     fmtMemory.ptd       = NULL;
 450     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 451     fmtMemory.lindex    = -1;
 452     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 453
 454     bool rc = false;
 455
 456     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 457     if ( SUCCEEDED(hr) ) {
 458         IDataObject *dataObject = m_dataObject->GetInterface();
 459
 460         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 461         if ( SUCCEEDED(hr) ) {
 462             rc = true;
 463         }
 464         else {
 465             wxLogApiError(wxT("IDataObject::SetData()"), hr);
 466         }
 467     }
 468     else {
 469         wxLogApiError(wxT("IDataObject::GetData()"), hr);
 470     }
 471
 472     return rc;
 473 }
 474
 475 // ----------------------------------------------------------------------------
 476 // callbacks used by wxIDropTarget
 477 // ----------------------------------------------------------------------------
 478
 479 // we need a data source, so wxIDropTarget gives it to us using this function
 480 void wxDropTarget::MSWSetDataSource(IDataObject *pIDataSource)
 481 {
 482     m_pIDataSource = pIDataSource;
 483 }
 484
 485 // determine if we accept data of this type
 486 bool wxDropTarget::MSWIsAcceptedData(IDataObject *pIDataSource) const
 487 {
 488     return MSWGetSupportedFormat(pIDataSource) != wxDF_INVALID;
 489 }
 490
 491 // ----------------------------------------------------------------------------
 492 // helper functions
 493 // ----------------------------------------------------------------------------
 494
 495 wxDataFormat wxDropTarget::GetMatchingPair()
 496 {
 497     return MSWGetSupportedFormat( m_pIDataSource );
 498 }
 499
 500 wxDataFormat wxDropTarget::MSWGetSupportedFormat(IDataObject *pIDataSource) const
 501 {
 502     // this strucutre describes a data of any type (first field will be
 503     // changing) being passed through global memory block.
 504     static FORMATETC s_fmtMemory = {
 505         0,
 506         NULL,
 507         DVASPECT_CONTENT,
 508         -1,
 509         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 510     };
 511
 512     // get the list of supported formats
 513     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 514     wxDataFormat format;
 515     wxDataFormat *formats;
 516     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 517
 518     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 519
 520     // cycle through all supported formats
 521     size_t n;
 522     for ( n = 0; n < nFormats; n++ ) {
 523         s_fmtMemory.cfFormat = formats[n];
 524
 525         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 526         //     for file drag and drop (format == CF_HDROP)
 527         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 528             format = formats[n];
 529
 530             break;
 531         }
 532     }
 533
 534     if ( formats != &format ) {
 535         // free memory if we allocated it
 536         delete [] formats;
 537     }
 538
 539     return n < nFormats ? format : wxFormatInvalid;
 540 }
 541
 542 // ----------------------------------------------------------------------------
 543 // private functions
 544 // ----------------------------------------------------------------------------
 545
 546 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 547 {
 548     switch ( dwEffect ) {
 549         case DROPEFFECT_COPY:
 550             return wxDragCopy;
 551
 552         case DROPEFFECT_LINK:
 553             return wxDragLink;
 554
 555         case DROPEFFECT_MOVE:
 556             return wxDragMove;
 557
 558         default:
 559             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 560             // fall through
 561
 562         case DROPEFFECT_NONE:
 563             return wxDragNone;
 564     }
 565 }
 566
 567 static DWORD ConvertDragResultToEffect(wxDragResult result)
 568 {
 569     switch ( result ) {
 570         case wxDragCopy:
 571             return DROPEFFECT_COPY;
 572
 573         case wxDragLink:
 574             return DROPEFFECT_LINK;
 575
 576         case wxDragMove:
 577             return DROPEFFECT_MOVE;
 578
 579         default:
 580             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 581             // fall through
 582
 583         case wxDragNone:
 584             return DROPEFFECT_NONE;
 585     }
 586 }
 587
 588 #endif // wxUSE_OLE && wxUSE_DRAG_AND_DROP