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/log.h"
  31 #endif
  32
  33 #include "wx/msw/private.h"
  34
  35 #ifdef __WXWINCE__
  36     #include <winreg.h>
  37     #include <ole2.h>
  38 #endif
  39
  40 #ifdef __WIN32__
  41     #if !defined(__GNUWIN32__) || wxUSE_NORLANDER_HEADERS
  42         #if wxCHECK_W32API_VERSION( 1, 0 )
  43             #include "wx/msw/wrapwin.h"
  44         #endif
  45         #include <shlobj.h>            // for DROPFILES structure
  46     #endif
  47 #else
  48     #include <shellapi.h>
  49 #endif
  50
  51 #include "wx/dnd.h"
  52
  53 #include "wx/msw/ole/oleutils.h"
  54
  55 // ----------------------------------------------------------------------------
  56 // IDropTarget interface: forward all interesting things to wxDropTarget
  57 // (the name is unfortunate, but wx_I_DropTarget is not at all the same thing
  58 //  as wxDropTarget which is 'public' class, while this one is private)
  59 // ----------------------------------------------------------------------------
  60
  61 class wxIDropTarget : public IDropTarget
  62 {
  63 public:
  64     wxIDropTarget(wxDropTarget *p);
  65     virtual ~wxIDropTarget();
  66
  67     // accessors for wxDropTarget
  68     void SetHwnd(HWND hwnd) { m_hwnd = hwnd; }
  69
  70     // IDropTarget methods
  71     STDMETHODIMP DragEnter(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  72     STDMETHODIMP DragOver(DWORD, POINTL, LPDWORD);
  73     STDMETHODIMP DragLeave();
  74     STDMETHODIMP Drop(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  75
  76     DECLARE_IUNKNOWN_METHODS;
  77
  78 protected:
  79     IDataObject  *m_pIDataObject; // !NULL between DragEnter and DragLeave/Drop
  80     wxDropTarget *m_pTarget;      // the real target (we're just a proxy)
  81
  82     HWND          m_hwnd;         // window we're associated with
  83
  84     // get default drop effect for given keyboard flags
  85     static inline DWORD GetDropEffect(DWORD flags, wxDragResult defaultAction);
  86
  87     DECLARE_NO_COPY_CLASS(wxIDropTarget)
  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, wxDragResult defaultAction)
 110 {
 111   if (defaultAction == wxDragCopy)
 112     return flags & MK_SHIFT ? DROPEFFECT_MOVE : DROPEFFECT_COPY;
 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, ConvertDragEffectToResult(
 192             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()))
 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(
 217             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()));
 218     }
 219     else {
 220         // can't accept data anyhow normally
 221         result = wxDragNone;
 222     }
 223
 224     // we need client coordinates to pass to wxWin functions
 225     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 226     {
 227         wxLogLastError(wxT("ScreenToClient"));
 228     }
 229
 230     *pdwEffect = ConvertDragResultToEffect(
 231                     m_pTarget->OnDragOver(pt.x, pt.y, result)
 232                  );
 233
 234     return S_OK;
 235 }
 236
 237 // Name    : wxIDropTarget::DragLeave
 238 // Purpose : Informs the drop target that the operation has left its window.
 239 // Returns : S_OK
 240 // Notes   : good place to do any clean-up
 241 STDMETHODIMP wxIDropTarget::DragLeave()
 242 {
 243   wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));
 244
 245   // remove the UI feedback
 246   m_pTarget->OnLeave();
 247
 248   // release the held object
 249   RELEASE_AND_NULL(m_pIDataObject);
 250
 251   return S_OK;
 252 }
 253
 254 // Name    : wxIDropTarget::Drop
 255 // Purpose : Instructs the drop target to paste data that was just now
 256 //           dropped on it.
 257 // Returns : S_OK
 258 // Params  : [in] IDataObject *pIDataSource     the data to paste
 259 //           [in] DWORD        grfKeyState      kbd & mouse state
 260 //           [in] POINTL       pt               where the drop occurred?
 261 //           [ouy]DWORD       *pdwEffect        operation effect
 262 // Notes   :
 263 STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 264                                  DWORD        grfKeyState,
 265                                  POINTL       pt,
 266                                  DWORD       *pdwEffect)
 267 {
 268     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
 269
 270     // TODO I don't know why there is this parameter, but so far I assume
 271     //      that it's the same we've already got in DragEnter
 272     wxASSERT( m_pIDataObject == pIDataSource );
 273
 274     // by default, nothing happens
 275     *pdwEffect = DROPEFFECT_NONE;
 276
 277     // we need client coordinates to pass to wxWin functions
 278     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 279     {
 280         wxLogLastError(wxT("ScreenToClient"));
 281     }
 282
 283     // first ask the drop target if it wants data
 284     if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
 285         // it does, so give it the data source
 286         m_pTarget->SetDataSource(pIDataSource);
 287
 288         // and now it has the data
 289         wxDragResult rc = ConvertDragEffectToResult(
 290             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()));
 291         rc = m_pTarget->OnData(pt.x, pt.y, rc);
 292         if ( wxIsDragResultOk(rc) ) {
 293             // operation succeeded
 294             *pdwEffect = ConvertDragResultToEffect(rc);
 295         }
 296         //else: *pdwEffect is already DROPEFFECT_NONE
 297     }
 298     //else: OnDrop() returned false, no need to copy data
 299
 300     // release the held object
 301     RELEASE_AND_NULL(m_pIDataObject);
 302
 303     return S_OK;
 304 }
 305
 306 // ============================================================================
 307 // wxDropTarget implementation
 308 // ============================================================================
 309
 310 // ----------------------------------------------------------------------------
 311 // ctor/dtor
 312 // ----------------------------------------------------------------------------
 313
 314 wxDropTarget::wxDropTarget(wxDataObject *dataObj)
 315             : wxDropTargetBase(dataObj)
 316 {
 317     // create an IDropTarget implementation which will notify us about d&d
 318     // operations.
 319     m_pIDropTarget = new wxIDropTarget(this);
 320     m_pIDropTarget->AddRef();
 321 }
 322
 323 wxDropTarget::~wxDropTarget()
 324 {
 325     ReleaseInterface(m_pIDropTarget);
 326 }
 327
 328 // ----------------------------------------------------------------------------
 329 // [un]register drop handler
 330 // ----------------------------------------------------------------------------
 331
 332 bool wxDropTarget::Register(WXHWND hwnd)
 333 {
 334     // FIXME
 335     // RegisterDragDrop not available on Windows CE >= 400?
 336     // Or maybe we can dynamically load them from ceshell.dll
 337     // or similar.
 338 #if defined(__WXWINCE__) && _WIN32_WCE >= 400
 339     wxUnusedVar(hwnd);
 340     return false;
 341 #else
 342     HRESULT hr;
 343
 344     // May exist in later WinCE versions
 345 #ifndef __WXWINCE__
 346     hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 347     if ( FAILED(hr) ) {
 348         wxLogApiError(wxT("CoLockObjectExternal"), hr);
 349         return false;
 350     }
 351 #endif
 352
 353     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 354     if ( FAILED(hr) ) {
 355     // May exist in later WinCE versions
 356 #ifndef __WXWINCE__
 357         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 358 #endif
 359         wxLogApiError(wxT("RegisterDragDrop"), hr);
 360         return false;
 361     }
 362
 363     // we will need the window handle for coords transformation later
 364     m_pIDropTarget->SetHwnd((HWND)hwnd);
 365
 366     return true;
 367 #endif
 368 }
 369
 370 void wxDropTarget::Revoke(WXHWND hwnd)
 371 {
 372 #if defined(__WXWINCE__) && _WIN32_WCE >= 400
 373     // Not available, see note above
 374     wxUnusedVar(hwnd);
 375 #else
 376     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 377
 378     if ( FAILED(hr) ) {
 379         wxLogApiError(wxT("RevokeDragDrop"), hr);
 380     }
 381
 382     // May exist in later WinCE versions
 383 #ifndef __WXWINCE__
 384     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 385 #endif
 386
 387     m_pIDropTarget->SetHwnd(0);
 388 #endif
 389 }
 390
 391 // ----------------------------------------------------------------------------
 392 // base class pure virtuals
 393 // ----------------------------------------------------------------------------
 394
 395 // OnDrop() is called only if we previously returned true from
 396 // IsAcceptedData(), so no need to check anything here
 397 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 398 {
 399     return true;
 400 }
 401
 402 // copy the data from the data source to the target data object
 403 bool wxDropTarget::GetData()
 404 {
 405     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 406     if ( format == wxDF_INVALID ) {
 407         // this is strange because IsAcceptedData() succeeded previously!
 408         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 409
 410         return false;
 411     }
 412
 413     STGMEDIUM stm;
 414     FORMATETC fmtMemory;
 415     fmtMemory.cfFormat  = format;
 416     fmtMemory.ptd       = NULL;
 417     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 418     fmtMemory.lindex    = -1;
 419     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 420
 421     bool rc = false;
 422
 423     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 424     if ( SUCCEEDED(hr) ) {
 425         IDataObject *dataObject = m_dataObject->GetInterface();
 426
 427         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 428         if ( SUCCEEDED(hr) ) {
 429             rc = true;
 430         }
 431         else {
 432             wxLogApiError(wxT("IDataObject::SetData()"), hr);
 433         }
 434     }
 435     else {
 436         wxLogApiError(wxT("IDataObject::GetData()"), hr);
 437     }
 438
 439     return rc;
 440 }
 441
 442 // ----------------------------------------------------------------------------
 443 // callbacks used by wxIDropTarget
 444 // ----------------------------------------------------------------------------
 445
 446 // we need a data source, so wxIDropTarget gives it to us using this function
 447 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 448 {
 449     m_pIDataSource = pIDataSource;
 450 }
 451
 452 // determine if we accept data of this type
 453 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 454 {
 455     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 456 }
 457
 458 // ----------------------------------------------------------------------------
 459 // helper functions
 460 // ----------------------------------------------------------------------------
 461
 462 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 463 {
 464     // this strucutre describes a data of any type (first field will be
 465     // changing) being passed through global memory block.
 466     static FORMATETC s_fmtMemory = {
 467         0,
 468         NULL,
 469         DVASPECT_CONTENT,
 470         -1,
 471         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 472     };
 473
 474     // get the list of supported formats
 475     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 476     wxDataFormat format;
 477     wxDataFormat *formats;
 478     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 479
 480     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 481
 482     // cycle through all supported formats
 483     size_t n;
 484     for ( n = 0; n < nFormats; n++ ) {
 485         s_fmtMemory.cfFormat = formats[n];
 486
 487         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 488         //     for file drag and drop (format == CF_HDROP)
 489         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 490             format = formats[n];
 491
 492             break;
 493         }
 494     }
 495
 496     if ( formats != &format ) {
 497         // free memory if we allocated it
 498         delete [] formats;
 499     }
 500
 501     return n < nFormats ? format : wxFormatInvalid;
 502 }
 503
 504 // ----------------------------------------------------------------------------
 505 // private functions
 506 // ----------------------------------------------------------------------------
 507
 508 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 509 {
 510     switch ( dwEffect ) {
 511         case DROPEFFECT_COPY:
 512             return wxDragCopy;
 513
 514         case DROPEFFECT_LINK:
 515             return wxDragLink;
 516
 517         case DROPEFFECT_MOVE:
 518             return wxDragMove;
 519
 520         default:
 521             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 522             // fall through
 523
 524         case DROPEFFECT_NONE:
 525             return wxDragNone;
 526     }
 527 }
 528
 529 static DWORD ConvertDragResultToEffect(wxDragResult result)
 530 {
 531     switch ( result ) {
 532         case wxDragCopy:
 533             return DROPEFFECT_COPY;
 534
 535         case wxDragLink:
 536             return DROPEFFECT_LINK;
 537
 538         case wxDragMove:
 539             return DROPEFFECT_MOVE;
 540
 541         default:
 542             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 543             // fall through
 544
 545         case wxDragNone:
 546             return DROPEFFECT_NONE;
 547     }
 548 }
 549
 550 #endif // wxUSE_OLE && wxUSE_DRAG_AND_DROP