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 license
  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
  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)
 110 {
 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,
 190                         ConvertDragEffectToResult(GetDropEffect(grfKeyState))
 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(GetDropEffect(grfKeyState));
 215     }
 216     else {
 217         // can't accept data anyhow normally
 218         result = wxDragNone;
 219     }
 220
 221     // we need client coordinates to pass to wxWin functions
 222     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 223     {
 224         wxLogLastError(wxT("ScreenToClient"));
 225     }
 226
 227     *pdwEffect = ConvertDragResultToEffect(
 228                     m_pTarget->OnDragOver(pt.x, pt.y, result)
 229                  );
 230
 231     return S_OK;
 232 }
 233
 234 // Name    : wxIDropTarget::DragLeave
 235 // Purpose : Informs the drop target that the operation has left its window.
 236 // Returns : S_OK
 237 // Notes   : good place to do any clean-up
 238 STDMETHODIMP wxIDropTarget::DragLeave()
 239 {
 240   wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));
 241
 242   // remove the UI feedback
 243   m_pTarget->OnLeave();
 244
 245   // release the held object
 246   RELEASE_AND_NULL(m_pIDataObject);
 247
 248   return S_OK;
 249 }
 250
 251 // Name    : wxIDropTarget::Drop
 252 // Purpose : Instructs the drop target to paste data that was just now
 253 //           dropped on it.
 254 // Returns : S_OK
 255 // Params  : [in] IDataObject *pIDataSource     the data to paste
 256 //           [in] DWORD        grfKeyState      kbd & mouse state
 257 //           [in] POINTL       pt               where the drop occured?
 258 //           [ouy]DWORD       *pdwEffect        operation effect
 259 // Notes   :
 260 STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 261                                  DWORD        grfKeyState,
 262                                  POINTL       pt,
 263                                  DWORD       *pdwEffect)
 264 {
 265     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
 266
 267     // TODO I don't know why there is this parameter, but so far I assume
 268     //      that it's the same we've already got in DragEnter
 269     wxASSERT( m_pIDataObject == pIDataSource );
 270
 271     // by default, nothing happens
 272     *pdwEffect = DROPEFFECT_NONE;
 273
 274     // we need client coordinates to pass to wxWin functions
 275     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 276     {
 277         wxLogLastError(wxT("ScreenToClient"));
 278     }
 279
 280     // first ask the drop target if it wants data
 281     if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
 282         // it does, so give it the data source
 283         m_pTarget->SetDataSource(pIDataSource);
 284
 285         // and now it has the data
 286         wxDragResult rc = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 287         rc = m_pTarget->OnData(pt.x, pt.y, rc);
 288         if ( wxIsDragResultOk(rc) ) {
 289             // operation succeeded
 290             *pdwEffect = ConvertDragResultToEffect(rc);
 291         }
 292         //else: *pdwEffect is already DROPEFFECT_NONE
 293     }
 294     //else: OnDrop() returned FALSE, no need to copy data
 295
 296     // release the held object
 297     RELEASE_AND_NULL(m_pIDataObject);
 298
 299     return S_OK;
 300 }
 301
 302 // ============================================================================
 303 // wxDropTarget implementation
 304 // ============================================================================
 305
 306 // ----------------------------------------------------------------------------
 307 // ctor/dtor
 308 // ----------------------------------------------------------------------------
 309
 310 wxDropTarget::wxDropTarget(wxDataObject *dataObj)
 311             : wxDropTargetBase(dataObj)
 312 {
 313     // create an IDropTarget implementation which will notify us about d&d
 314     // operations.
 315     m_pIDropTarget = new wxIDropTarget(this);
 316     m_pIDropTarget->AddRef();
 317 }
 318
 319 wxDropTarget::~wxDropTarget()
 320 {
 321     ReleaseInterface(m_pIDropTarget);
 322 }
 323
 324 // ----------------------------------------------------------------------------
 325 // [un]register drop handler
 326 // ----------------------------------------------------------------------------
 327
 328 bool wxDropTarget::Register(WXHWND hwnd)
 329 {
 330     HRESULT hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 331     if ( FAILED(hr) ) {
 332         wxLogApiError(wxT("CoLockObjectExternal"), hr);
 333         return FALSE;
 334     }
 335
 336     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 337     if ( FAILED(hr) ) {
 338         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 339
 340         wxLogApiError(wxT("RegisterDragDrop"), hr);
 341         return FALSE;
 342     }
 343
 344     // we will need the window handle for coords transformation later
 345     m_pIDropTarget->SetHwnd((HWND)hwnd);
 346
 347     return TRUE;
 348 }
 349
 350 void wxDropTarget::Revoke(WXHWND hwnd)
 351 {
 352     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 353
 354     if ( FAILED(hr) ) {
 355         wxLogApiError(wxT("RevokeDragDrop"), hr);
 356     }
 357
 358     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 359
 360     m_pIDropTarget->SetHwnd(0);
 361 }
 362
 363 // ----------------------------------------------------------------------------
 364 // base class pure virtuals
 365 // ----------------------------------------------------------------------------
 366
 367 // OnDrop() is called only if we previously returned TRUE from
 368 // IsAcceptedData(), so no need to check anything here
 369 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 370 {
 371     return TRUE;
 372 }
 373
 374 // copy the data from the data source to the target data object
 375 bool wxDropTarget::GetData()
 376 {
 377     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 378     if ( format == wxDF_INVALID ) {
 379         // this is strange because IsAcceptedData() succeeded previously!
 380         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 381
 382         return FALSE;
 383     }
 384
 385     STGMEDIUM stm;
 386     FORMATETC fmtMemory;
 387     fmtMemory.cfFormat  = format;
 388     fmtMemory.ptd       = NULL;
 389     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 390     fmtMemory.lindex    = -1;
 391     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 392
 393     bool rc = FALSE;
 394
 395     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 396     if ( SUCCEEDED(hr) ) {
 397         IDataObject *dataObject = m_dataObject->GetInterface();
 398
 399         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 400         if ( SUCCEEDED(hr) ) {
 401             rc = TRUE;
 402         }
 403         else {
 404             wxLogApiError(wxT("IDataObject::SetData()"), hr);
 405         }
 406     }
 407     else {
 408         wxLogApiError(wxT("IDataObject::GetData()"), hr);
 409     }
 410
 411     return rc;
 412 }
 413
 414 // ----------------------------------------------------------------------------
 415 // callbacks used by wxIDropTarget
 416 // ----------------------------------------------------------------------------
 417
 418 // we need a data source, so wxIDropTarget gives it to us using this function
 419 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 420 {
 421     m_pIDataSource = pIDataSource;
 422 }
 423
 424 // determine if we accept data of this type
 425 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 426 {
 427     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 428 }
 429
 430 // ----------------------------------------------------------------------------
 431 // helper functions
 432 // ----------------------------------------------------------------------------
 433
 434 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 435 {
 436     // this strucutre describes a data of any type (first field will be
 437     // changing) being passed through global memory block.
 438     static FORMATETC s_fmtMemory = {
 439         0,
 440         NULL,
 441         DVASPECT_CONTENT,
 442         -1,
 443         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 444     };
 445
 446     // get the list of supported formats
 447     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 448     wxDataFormat format;
 449     wxDataFormat *formats;
 450     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 451
 452     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 453
 454     // cycle through all supported formats
 455     size_t n;
 456     for ( n = 0; n < nFormats; n++ ) {
 457         s_fmtMemory.cfFormat = formats[n];
 458
 459         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 460         //     for file drag and drop (format == CF_HDROP)
 461         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 462             format = formats[n];
 463
 464             break;
 465         }
 466     }
 467
 468     if ( formats != &format ) {
 469         // free memory if we allocated it
 470         delete [] formats;
 471     }
 472
 473     return n < nFormats ? format : wxFormatInvalid;
 474 }
 475
 476 // ----------------------------------------------------------------------------
 477 // private functions
 478 // ----------------------------------------------------------------------------
 479
 480 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 481 {
 482     switch ( dwEffect ) {
 483         case DROPEFFECT_COPY:
 484             return wxDragCopy;
 485
 486         case DROPEFFECT_LINK:
 487             return wxDragLink;
 488
 489         case DROPEFFECT_MOVE:
 490             return wxDragMove;
 491
 492         default:
 493             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 494             // fall through
 495
 496         case DROPEFFECT_NONE:
 497             return wxDragNone;
 498     }
 499 }
 500
 501 static DWORD ConvertDragResultToEffect(wxDragResult result)
 502 {
 503     switch ( result ) {
 504         case wxDragCopy:
 505             return DROPEFFECT_COPY;
 506
 507         case wxDragLink:
 508             return DROPEFFECT_LINK;
 509
 510         case wxDragMove:
 511             return DROPEFFECT_MOVE;
 512
 513         default:
 514             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 515             // fall through
 516
 517         case wxDragNone:
 518             return DROPEFFECT_NONE;
 519     }
 520 }
 521
 522 #endif
 523  // wxUSE_DRAG_AND_DROP