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 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 #include "wx/setup.h"
  28
  29 #if wxUSE_OLE && wxUSE_DRAG_AND_DROP
  30
  31 #include "wx/msw/private.h"
  32 #include "wx/log.h"
  33
  34 #ifdef __WXWINCE__
  35     #include <winreg.h>
  36     #include <ole2.h>
  37 #endif
  38
  39 #ifdef __WIN32__
  40     #if !defined(__GNUWIN32__) || wxUSE_NORLANDER_HEADERS
  41         #if wxCHECK_W32API_VERSION( 1, 0 )
  42             #include "wx/msw/wrapwin.h"
  43         #endif
  44         #include <shlobj.h>            // for DROPFILES structure
  45     #endif
  46 #else
  47     #include <shellapi.h>
  48 #endif
  49
  50 #include "wx/dnd.h"
  51
  52 #include "wx/msw/ole/oleutils.h"
  53
  54 // ----------------------------------------------------------------------------
  55 // IDropTarget interface: forward all interesting things to wxDropTarget
  56 // (the name is unfortunate, but wx_I_DropTarget is not at all the same thing
  57 //  as wxDropTarget which is 'public' class, while this one is private)
  58 // ----------------------------------------------------------------------------
  59
  60 class wxIDropTarget : public IDropTarget
  61 {
  62 public:
  63     wxIDropTarget(wxDropTarget *p);
  64     virtual ~wxIDropTarget();
  65
  66     // accessors for wxDropTarget
  67     void SetHwnd(HWND hwnd) { m_hwnd = hwnd; }
  68
  69     // IDropTarget methods
  70     STDMETHODIMP DragEnter(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  71     STDMETHODIMP DragOver(DWORD, POINTL, LPDWORD);
  72     STDMETHODIMP DragLeave();
  73     STDMETHODIMP Drop(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  74
  75     DECLARE_IUNKNOWN_METHODS;
  76
  77 protected:
  78     IDataObject  *m_pIDataObject; // !NULL between DragEnter and DragLeave/Drop
  79     wxDropTarget *m_pTarget;      // the real target (we're just a proxy)
  80
  81     HWND          m_hwnd;         // window we're associated with
  82
  83     // get default drop effect for given keyboard flags
  84     static inline DWORD GetDropEffect(DWORD flags, wxDragResult defaultAction);
  85
  86     DECLARE_NO_COPY_CLASS(wxIDropTarget)
  87 };
  88
  89 // ----------------------------------------------------------------------------
  90 // private functions
  91 // ----------------------------------------------------------------------------
  92
  93 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect);
  94 static DWORD ConvertDragResultToEffect(wxDragResult result);
  95
  96 // ============================================================================
  97 // wxIDropTarget implementation
  98 // ============================================================================
  99
 100 // Name    : static wxIDropTarget::GetDropEffect
 101 // Purpose : determine the drop operation from keyboard/mouse state.
 102 // Returns : DWORD combined from DROPEFFECT_xxx constants
 103 // Params  : [in] DWORD flags       kbd & mouse flags as passed to
 104 //                                  IDropTarget methods
 105 // Notes   : We do "move" normally and "copy" if <Ctrl> is pressed,
 106 //           which is the standard behaviour (currently there is no
 107 //           way to redefine it)
 108 DWORD wxIDropTarget::GetDropEffect(DWORD flags, wxDragResult defaultAction)
 109 {
 110   if (defaultAction == wxDragCopy)
 111     return flags & MK_SHIFT ? DROPEFFECT_MOVE : DROPEFFECT_COPY;
 112   return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
 113 }
 114
 115 wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
 116 {
 117   m_pTarget      = pTarget;
 118   m_pIDataObject = NULL;
 119 }
 120
 121 wxIDropTarget::~wxIDropTarget()
 122 {
 123 }
 124
 125 BEGIN_IID_TABLE(wxIDropTarget)
 126   ADD_IID(Unknown)
 127   ADD_IID(DropTarget)
 128 END_IID_TABLE;
 129
 130 IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
 131
 132 // Name    : wxIDropTarget::DragEnter
 133 // Purpose : Called when the mouse enters the window (dragging something)
 134 // Returns : S_OK
 135 // Params  : [in] IDataObject *pIDataSource : source data
 136 //           [in] DWORD        grfKeyState  : kbd & mouse state
 137 //           [in] POINTL       pt           : mouse coordinates
 138 //           [out]DWORD       *pdwEffect    : effect flag
 139 // Notes   :
 140 STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 141                                       DWORD        grfKeyState,
 142                                       POINTL       pt,
 143                                       DWORD       *pdwEffect)
 144 {
 145     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
 146
 147     wxASSERT_MSG( m_pIDataObject == NULL,
 148                   _T("drop target must have data object") );
 149
 150     // show the list of formats supported by the source data object for the
 151     // debugging purposes, this is quite useful sometimes - please don't remove
 152 #if 0
 153     IEnumFORMATETC *penumFmt;
 154     if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
 155     {
 156         FORMATETC fmt;
 157         while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
 158         {
 159             wxLogDebug(_T("Drop source supports format %s"),
 160                        wxDataObject::GetFormatName(fmt.cfFormat));
 161         }
 162
 163         penumFmt->Release();
 164     }
 165     else
 166     {
 167         wxLogLastError(_T("IDataObject::EnumFormatEtc"));
 168     }
 169 #endif // 0
 170
 171     if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
 172         // we don't accept this kind of data
 173         *pdwEffect = DROPEFFECT_NONE;
 174
 175         return S_OK;
 176     }
 177
 178     // get hold of the data object
 179     m_pIDataObject = pIDataSource;
 180     m_pIDataObject->AddRef();
 181
 182     // we need client coordinates to pass to wxWin functions
 183     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 184     {
 185         wxLogLastError(wxT("ScreenToClient"));
 186     }
 187
 188     // give some visual feedback
 189     *pdwEffect = ConvertDragResultToEffect(
 190         m_pTarget->OnEnter(pt.x, pt.y, ConvertDragEffectToResult(
 191             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()))
 192                     )
 193                  );
 194
 195     return S_OK;
 196 }
 197
 198 // Name    : wxIDropTarget::DragOver
 199 // Purpose : Indicates that the mouse was moved inside the window represented
 200 //           by this drop target.
 201 // Returns : S_OK
 202 // Params  : [in] DWORD   grfKeyState     kbd & mouse state
 203 //           [in] POINTL  pt              mouse coordinates
 204 //           [out]LPDWORD pdwEffect       effect flag
 205 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 206 //           very efficient.
 207 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 208                                      POINTL  pt,
 209                                      LPDWORD pdwEffect)
 210 {
 211     // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 212
 213     wxDragResult result;
 214     if ( m_pIDataObject ) {
 215         result = ConvertDragEffectToResult(
 216             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()));
 217     }
 218     else {
 219         // can't accept data anyhow normally
 220         result = wxDragNone;
 221     }
 222
 223     // we need client coordinates to pass to wxWin functions
 224     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 225     {
 226         wxLogLastError(wxT("ScreenToClient"));
 227     }
 228
 229     *pdwEffect = ConvertDragResultToEffect(
 230                     m_pTarget->OnDragOver(pt.x, pt.y, result)
 231                  );
 232
 233     return S_OK;
 234 }
 235
 236 // Name    : wxIDropTarget::DragLeave
 237 // Purpose : Informs the drop target that the operation has left its window.
 238 // Returns : S_OK
 239 // Notes   : good place to do any clean-up
 240 STDMETHODIMP wxIDropTarget::DragLeave()
 241 {
 242   wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));
 243
 244   // remove the UI feedback
 245   m_pTarget->OnLeave();
 246
 247   // release the held object
 248   RELEASE_AND_NULL(m_pIDataObject);
 249
 250   return S_OK;
 251 }
 252
 253 // Name    : wxIDropTarget::Drop
 254 // Purpose : Instructs the drop target to paste data that was just now
 255 //           dropped on it.
 256 // Returns : S_OK
 257 // Params  : [in] IDataObject *pIDataSource     the data to paste
 258 //           [in] DWORD        grfKeyState      kbd & mouse state
 259 //           [in] POINTL       pt               where the drop occurred?
 260 //           [ouy]DWORD       *pdwEffect        operation effect
 261 // Notes   :
 262 STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 263                                  DWORD        grfKeyState,
 264                                  POINTL       pt,
 265                                  DWORD       *pdwEffect)
 266 {
 267     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
 268
 269     // TODO I don't know why there is this parameter, but so far I assume
 270     //      that it's the same we've already got in DragEnter
 271     wxASSERT( m_pIDataObject == pIDataSource );
 272
 273     // by default, nothing happens
 274     *pdwEffect = DROPEFFECT_NONE;
 275
 276     // we need client coordinates to pass to wxWin functions
 277     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 278     {
 279         wxLogLastError(wxT("ScreenToClient"));
 280     }
 281
 282     // first ask the drop target if it wants data
 283     if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
 284         // it does, so give it the data source
 285         m_pTarget->SetDataSource(pIDataSource);
 286
 287         // and now it has the data
 288         wxDragResult rc = ConvertDragEffectToResult(
 289             GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()));
 290         rc = m_pTarget->OnData(pt.x, pt.y, rc);
 291         if ( wxIsDragResultOk(rc) ) {
 292             // operation succeeded
 293             *pdwEffect = ConvertDragResultToEffect(rc);
 294         }
 295         //else: *pdwEffect is already DROPEFFECT_NONE
 296     }
 297     //else: OnDrop() returned false, no need to copy data
 298
 299     // release the held object
 300     RELEASE_AND_NULL(m_pIDataObject);
 301
 302     return S_OK;
 303 }
 304
 305 // ============================================================================
 306 // wxDropTarget implementation
 307 // ============================================================================
 308
 309 // ----------------------------------------------------------------------------
 310 // ctor/dtor
 311 // ----------------------------------------------------------------------------
 312
 313 wxDropTarget::wxDropTarget(wxDataObject *dataObj)
 314             : wxDropTargetBase(dataObj)
 315 {
 316     // create an IDropTarget implementation which will notify us about d&d
 317     // operations.
 318     m_pIDropTarget = new wxIDropTarget(this);
 319     m_pIDropTarget->AddRef();
 320 }
 321
 322 wxDropTarget::~wxDropTarget()
 323 {
 324     ReleaseInterface(m_pIDropTarget);
 325 }
 326
 327 // ----------------------------------------------------------------------------
 328 // [un]register drop handler
 329 // ----------------------------------------------------------------------------
 330
 331 bool wxDropTarget::Register(WXHWND hwnd)
 332 {
 333     // FIXME
 334     // RegisterDragDrop not available on Windows CE >= 400?
 335     // Or maybe we can dynamically load them from ceshell.dll
 336     // or similar.
 337 #if defined(__WXWINCE__) && _WIN32_WCE >= 400
 338     wxUnusedVar(hwnd);
 339     return false;
 340 #else
 341     HRESULT hr;
 342
 343     // May exist in later WinCE versions
 344 #ifndef __WXWINCE__
 345     hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 346     if ( FAILED(hr) ) {
 347         wxLogApiError(wxT("CoLockObjectExternal"), hr);
 348         return false;
 349     }
 350 #endif
 351
 352     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 353     if ( FAILED(hr) ) {
 354     // May exist in later WinCE versions
 355 #ifndef __WXWINCE__
 356         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 357 #endif
 358         wxLogApiError(wxT("RegisterDragDrop"), hr);
 359         return false;
 360     }
 361
 362     // we will need the window handle for coords transformation later
 363     m_pIDropTarget->SetHwnd((HWND)hwnd);
 364
 365     return true;
 366 #endif
 367 }
 368
 369 void wxDropTarget::Revoke(WXHWND hwnd)
 370 {
 371 #if defined(__WXWINCE__) && _WIN32_WCE >= 400
 372     // Not available, see note above
 373     wxUnusedVar(hwnd);
 374 #else
 375     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 376
 377     if ( FAILED(hr) ) {
 378         wxLogApiError(wxT("RevokeDragDrop"), hr);
 379     }
 380
 381     // May exist in later WinCE versions
 382 #ifndef __WXWINCE__
 383     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 384 #endif
 385
 386     m_pIDropTarget->SetHwnd(0);
 387 #endif
 388 }
 389
 390 // ----------------------------------------------------------------------------
 391 // base class pure virtuals
 392 // ----------------------------------------------------------------------------
 393
 394 // OnDrop() is called only if we previously returned true from
 395 // IsAcceptedData(), so no need to check anything here
 396 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 397 {
 398     return true;
 399 }
 400
 401 // copy the data from the data source to the target data object
 402 bool wxDropTarget::GetData()
 403 {
 404     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 405     if ( format == wxDF_INVALID ) {
 406         // this is strange because IsAcceptedData() succeeded previously!
 407         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 408
 409         return false;
 410     }
 411
 412     STGMEDIUM stm;
 413     FORMATETC fmtMemory;
 414     fmtMemory.cfFormat  = format;
 415     fmtMemory.ptd       = NULL;
 416     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 417     fmtMemory.lindex    = -1;
 418     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 419
 420     bool rc = false;
 421
 422     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 423     if ( SUCCEEDED(hr) ) {
 424         IDataObject *dataObject = m_dataObject->GetInterface();
 425
 426         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 427         if ( SUCCEEDED(hr) ) {
 428             rc = true;
 429         }
 430         else {
 431             wxLogApiError(wxT("IDataObject::SetData()"), hr);
 432         }
 433     }
 434     else {
 435         wxLogApiError(wxT("IDataObject::GetData()"), hr);
 436     }
 437
 438     return rc;
 439 }
 440
 441 // ----------------------------------------------------------------------------
 442 // callbacks used by wxIDropTarget
 443 // ----------------------------------------------------------------------------
 444
 445 // we need a data source, so wxIDropTarget gives it to us using this function
 446 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 447 {
 448     m_pIDataSource = pIDataSource;
 449 }
 450
 451 // determine if we accept data of this type
 452 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 453 {
 454     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 455 }
 456
 457 // ----------------------------------------------------------------------------
 458 // helper functions
 459 // ----------------------------------------------------------------------------
 460
 461 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 462 {
 463     // this strucutre describes a data of any type (first field will be
 464     // changing) being passed through global memory block.
 465     static FORMATETC s_fmtMemory = {
 466         0,
 467         NULL,
 468         DVASPECT_CONTENT,
 469         -1,
 470         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 471     };
 472
 473     // get the list of supported formats
 474     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 475     wxDataFormat format;
 476     wxDataFormat *formats;
 477     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 478
 479     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 480
 481     // cycle through all supported formats
 482     size_t n;
 483     for ( n = 0; n < nFormats; n++ ) {
 484         s_fmtMemory.cfFormat = formats[n];
 485
 486         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 487         //     for file drag and drop (format == CF_HDROP)
 488         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 489             format = formats[n];
 490
 491             break;
 492         }
 493     }
 494
 495     if ( formats != &format ) {
 496         // free memory if we allocated it
 497         delete [] formats;
 498     }
 499
 500     return n < nFormats ? format : wxFormatInvalid;
 501 }
 502
 503 // ----------------------------------------------------------------------------
 504 // private functions
 505 // ----------------------------------------------------------------------------
 506
 507 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 508 {
 509     switch ( dwEffect ) {
 510         case DROPEFFECT_COPY:
 511             return wxDragCopy;
 512
 513         case DROPEFFECT_LINK:
 514             return wxDragLink;
 515
 516         case DROPEFFECT_MOVE:
 517             return wxDragMove;
 518
 519         default:
 520             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 521             // fall through
 522
 523         case DROPEFFECT_NONE:
 524             return wxDragNone;
 525     }
 526 }
 527
 528 static DWORD ConvertDragResultToEffect(wxDragResult result)
 529 {
 530     switch ( result ) {
 531         case wxDragCopy:
 532             return DROPEFFECT_COPY;
 533
 534         case wxDragLink:
 535             return DROPEFFECT_LINK;
 536
 537         case wxDragMove:
 538             return DROPEFFECT_MOVE;
 539
 540         default:
 541             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 542             // fall through
 543
 544         case wxDragNone:
 545             return DROPEFFECT_NONE;
 546     }
 547 }
 548
 549 #endif
 550  // wxUSE_DRAG_AND_DROP