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 #include "wx/msw/private.h"
  30 #include "wx/log.h"
  31
  32 #ifdef __WXWINCE__
  33     #include <winreg.h>
  34     #include <ole2.h>
  35 #endif
  36
  37 #ifdef __WIN32__
  38     #if !defined(__GNUWIN32__) || wxUSE_NORLANDER_HEADERS
  39         #if wxCHECK_W32API_VERSION( 1, 0 )
  40             #include "wx/msw/wrapwin.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 #include "wx/msw/ole/oleutils.h"
  51
  52 // ----------------------------------------------------------------------------
  53 // IDropTarget interface: forward all interesting things to wxDropTarget
  54 // (the name is unfortunate, but wx_I_DropTarget is not at all the same thing
  55 //  as wxDropTarget which is 'public' class, while this one is private)
  56 // ----------------------------------------------------------------------------
  57
  58 class wxIDropTarget : public IDropTarget
  59 {
  60 public:
  61     wxIDropTarget(wxDropTarget *p);
  62     virtual ~wxIDropTarget();
  63
  64     // accessors for wxDropTarget
  65     void SetHwnd(HWND hwnd) { m_hwnd = hwnd; }
  66
  67     // IDropTarget methods
  68     STDMETHODIMP DragEnter(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  69     STDMETHODIMP DragOver(DWORD, POINTL, LPDWORD);
  70     STDMETHODIMP DragLeave();
  71     STDMETHODIMP Drop(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  72
  73     DECLARE_IUNKNOWN_METHODS;
  74
  75 protected:
  76     IDataObject  *m_pIDataObject; // !NULL between DragEnter and DragLeave/Drop
  77     wxDropTarget *m_pTarget;      // the real target (we're just a proxy)
  78
  79     HWND          m_hwnd;         // window we're associated with
  80
  81     // get default drop effect for given keyboard flags
  82     static inline DWORD GetDropEffect(DWORD flags, wxDragResult defaultAction);
  83
  84     DECLARE_NO_COPY_CLASS(wxIDropTarget)
  85 };
  86
  87 // ----------------------------------------------------------------------------
  88 // private functions
  89 // ----------------------------------------------------------------------------
  90
  91 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect);
  92 static DWORD ConvertDragResultToEffect(wxDragResult result);
  93
  94 // ============================================================================
  95 // wxIDropTarget implementation
  96 // ============================================================================
  97
  98 // Name    : static wxIDropTarget::GetDropEffect
  99 // Purpose : determine the drop operation from keyboard/mouse state.
 100 // Returns : DWORD combined from DROPEFFECT_xxx constants
 101 // Params  : [in] DWORD flags       kbd & mouse flags as passed to
 102 //                                  IDropTarget methods
 103 // Notes   : We do "move" normally and "copy" if <Ctrl> is pressed,
 104 //           which is the standard behaviour (currently there is no
 105 //           way to redefine it)
 106 DWORD wxIDropTarget::GetDropEffect(DWORD flags, wxDragResult defaultAction)
 107 {
 108   if (defaultAction == wxDragCopy)
 109     return flags & MK_SHIFT ? DROPEFFECT_MOVE : DROPEFFECT_COPY;
 110   return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
 111 }
 112
 113 wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
 114 {
 115   m_pTarget      = pTarget;
 116   m_pIDataObject = NULL;
 117 }
 118
 119 wxIDropTarget::~wxIDropTarget()
 120 {
 121 }
 122
 123 BEGIN_IID_TABLE(wxIDropTarget)
 124   ADD_IID(Unknown)
 125   ADD_IID(DropTarget)
 126 END_IID_TABLE;
 127
 128 IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
 129
 130 // Name    : wxIDropTarget::DragEnter
 131 // Purpose : Called when the mouse enters the window (dragging something)
 132 // Returns : S_OK
 133 // Params  : [in] IDataObject *pIDataSource : source data
 134 //           [in] DWORD        grfKeyState  : kbd & mouse state
 135 //           [in] POINTL       pt           : mouse coordinates
 136 //           [out]DWORD       *pdwEffect    : effect flag
 137 // Notes   :
 138 STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 139                                       DWORD        grfKeyState,
 140                                       POINTL       pt,
 141                                       DWORD       *pdwEffect)
 142 {
 143     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
 144
 145     wxASSERT_MSG( m_pIDataObject == NULL,
 146                   _T("drop target must have data object") );
 147
 148     // show the list of formats supported by the source data object for the
 149     // debugging purposes, this is quite useful sometimes - please don't remove
 150 #if 0
 151     IEnumFORMATETC *penumFmt;
 152     if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
 153     {
 154         FORMATETC fmt;
 155         while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
 156         {
 157             wxLogDebug(_T("Drop source supports format %s"),
 158                        wxDataObject::GetFormatName(fmt.cfFormat));
 159         }
 160
 161         penumFmt->Release();
 162     }
 163     else
 164     {
 165         wxLogLastError(_T("IDataObject::EnumFormatEtc"));
 166     }
 167 #endif // 0
 168
 169     if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
 170         // we don't accept this kind of data
 171         *pdwEffect = DROPEFFECT_NONE;
 172
 173         return S_OK;
 174     }
 175
 176     // get hold of the data object
 177     m_pIDataObject = pIDataSource;
 178     m_pIDataObject->AddRef();
 179
 180     // we need client coordinates to pass to wxWin functions
 181     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 182     {
 183         wxLogLastError(wxT("ScreenToClient"));
 184     }
 185
 186     // give some visual feedback
 187     *pdwEffect = ConvertDragResultToEffect(
 188         m_pTarget->OnEnter(pt.x, pt.y, ConvertDragEffectToResult(
 189             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()))
 190                     )
 191                  );
 192
 193     return S_OK;
 194 }
 195
 196 // Name    : wxIDropTarget::DragOver
 197 // Purpose : Indicates that the mouse was moved inside the window represented
 198 //           by this drop target.
 199 // Returns : S_OK
 200 // Params  : [in] DWORD   grfKeyState     kbd & mouse state
 201 //           [in] POINTL  pt              mouse coordinates
 202 //           [out]LPDWORD pdwEffect       effect flag
 203 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 204 //           very efficient.
 205 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 206                                      POINTL  pt,
 207                                      LPDWORD pdwEffect)
 208 {
 209     // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 210
 211     wxDragResult result;
 212     if ( m_pIDataObject ) {
 213         result = ConvertDragEffectToResult(
 214             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()));
 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 occurred?
 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(
 287             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()));
 288         rc = m_pTarget->OnData(pt.x, pt.y, rc);
 289         if ( wxIsDragResultOk(rc) ) {
 290             // operation succeeded
 291             *pdwEffect = ConvertDragResultToEffect(rc);
 292         }
 293         //else: *pdwEffect is already DROPEFFECT_NONE
 294     }
 295     //else: OnDrop() returned false, no need to copy data
 296
 297     // release the held object
 298     RELEASE_AND_NULL(m_pIDataObject);
 299
 300     return S_OK;
 301 }
 302
 303 // ============================================================================
 304 // wxDropTarget implementation
 305 // ============================================================================
 306
 307 // ----------------------------------------------------------------------------
 308 // ctor/dtor
 309 // ----------------------------------------------------------------------------
 310
 311 wxDropTarget::wxDropTarget(wxDataObject *dataObj)
 312             : wxDropTargetBase(dataObj)
 313 {
 314     // create an IDropTarget implementation which will notify us about d&d
 315     // operations.
 316     m_pIDropTarget = new wxIDropTarget(this);
 317     m_pIDropTarget->AddRef();
 318 }
 319
 320 wxDropTarget::~wxDropTarget()
 321 {
 322     ReleaseInterface(m_pIDropTarget);
 323 }
 324
 325 // ----------------------------------------------------------------------------
 326 // [un]register drop handler
 327 // ----------------------------------------------------------------------------
 328
 329 bool wxDropTarget::Register(WXHWND hwnd)
 330 {
 331     // FIXME
 332     // RegisterDragDrop not available on Windows CE >= 400?
 333     // Or maybe we can dynamically load them from ceshell.dll
 334     // or similar.
 335 #if defined(__WXWINCE__) && _WIN32_WCE >= 400
 336     wxUnusedVar(hwnd);
 337     return false;
 338 #else
 339     HRESULT hr;
 340
 341     // May exist in later WinCE versions
 342 #ifndef __WXWINCE__
 343     hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 344     if ( FAILED(hr) ) {
 345         wxLogApiError(wxT("CoLockObjectExternal"), hr);
 346         return false;
 347     }
 348 #endif
 349
 350     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 351     if ( FAILED(hr) ) {
 352     // May exist in later WinCE versions
 353 #ifndef __WXWINCE__
 354         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 355 #endif
 356         wxLogApiError(wxT("RegisterDragDrop"), hr);
 357         return false;
 358     }
 359
 360     // we will need the window handle for coords transformation later
 361     m_pIDropTarget->SetHwnd((HWND)hwnd);
 362
 363     return true;
 364 #endif
 365 }
 366
 367 void wxDropTarget::Revoke(WXHWND hwnd)
 368 {
 369 #if defined(__WXWINCE__) && _WIN32_WCE >= 400
 370     // Not available, see note above
 371     wxUnusedVar(hwnd);
 372 #else
 373     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 374
 375     if ( FAILED(hr) ) {
 376         wxLogApiError(wxT("RevokeDragDrop"), hr);
 377     }
 378
 379     // May exist in later WinCE versions
 380 #ifndef __WXWINCE__
 381     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 382 #endif
 383
 384     m_pIDropTarget->SetHwnd(0);
 385 #endif
 386 }
 387
 388 // ----------------------------------------------------------------------------
 389 // base class pure virtuals
 390 // ----------------------------------------------------------------------------
 391
 392 // OnDrop() is called only if we previously returned true from
 393 // IsAcceptedData(), so no need to check anything here
 394 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 395 {
 396     return true;
 397 }
 398
 399 // copy the data from the data source to the target data object
 400 bool wxDropTarget::GetData()
 401 {
 402     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 403     if ( format == wxDF_INVALID ) {
 404         // this is strange because IsAcceptedData() succeeded previously!
 405         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 406
 407         return false;
 408     }
 409
 410     STGMEDIUM stm;
 411     FORMATETC fmtMemory;
 412     fmtMemory.cfFormat  = format;
 413     fmtMemory.ptd       = NULL;
 414     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 415     fmtMemory.lindex    = -1;
 416     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 417
 418     bool rc = false;
 419
 420     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 421     if ( SUCCEEDED(hr) ) {
 422         IDataObject *dataObject = m_dataObject->GetInterface();
 423
 424         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 425         if ( SUCCEEDED(hr) ) {
 426             rc = true;
 427         }
 428         else {
 429             wxLogApiError(wxT("IDataObject::SetData()"), hr);
 430         }
 431     }
 432     else {
 433         wxLogApiError(wxT("IDataObject::GetData()"), hr);
 434     }
 435
 436     return rc;
 437 }
 438
 439 // ----------------------------------------------------------------------------
 440 // callbacks used by wxIDropTarget
 441 // ----------------------------------------------------------------------------
 442
 443 // we need a data source, so wxIDropTarget gives it to us using this function
 444 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 445 {
 446     m_pIDataSource = pIDataSource;
 447 }
 448
 449 // determine if we accept data of this type
 450 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 451 {
 452     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 453 }
 454
 455 // ----------------------------------------------------------------------------
 456 // helper functions
 457 // ----------------------------------------------------------------------------
 458
 459 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 460 {
 461     // this strucutre describes a data of any type (first field will be
 462     // changing) being passed through global memory block.
 463     static FORMATETC s_fmtMemory = {
 464         0,
 465         NULL,
 466         DVASPECT_CONTENT,
 467         -1,
 468         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 469     };
 470
 471     // get the list of supported formats
 472     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 473     wxDataFormat format;
 474     wxDataFormat *formats;
 475     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 476
 477     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 478
 479     // cycle through all supported formats
 480     size_t n;
 481     for ( n = 0; n < nFormats; n++ ) {
 482         s_fmtMemory.cfFormat = formats[n];
 483
 484         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 485         //     for file drag and drop (format == CF_HDROP)
 486         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 487             format = formats[n];
 488
 489             break;
 490         }
 491     }
 492
 493     if ( formats != &format ) {
 494         // free memory if we allocated it
 495         delete [] formats;
 496     }
 497
 498     return n < nFormats ? format : wxFormatInvalid;
 499 }
 500
 501 // ----------------------------------------------------------------------------
 502 // private functions
 503 // ----------------------------------------------------------------------------
 504
 505 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 506 {
 507     switch ( dwEffect ) {
 508         case DROPEFFECT_COPY:
 509             return wxDragCopy;
 510
 511         case DROPEFFECT_LINK:
 512             return wxDragLink;
 513
 514         case DROPEFFECT_MOVE:
 515             return wxDragMove;
 516
 517         default:
 518             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 519             // fall through
 520
 521         case DROPEFFECT_NONE:
 522             return wxDragNone;
 523     }
 524 }
 525
 526 static DWORD ConvertDragResultToEffect(wxDragResult result)
 527 {
 528     switch ( result ) {
 529         case wxDragCopy:
 530             return DROPEFFECT_COPY;
 531
 532         case wxDragLink:
 533             return DROPEFFECT_LINK;
 534
 535         case wxDragMove:
 536             return DROPEFFECT_MOVE;
 537
 538         default:
 539             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 540             // fall through
 541
 542         case wxDragNone:
 543             return DROPEFFECT_NONE;
 544     }
 545 }
 546
 547 #endif
 548  // wxUSE_DRAG_AND_DROP