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