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