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 #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/msw/private.h"
  36 #include "wx/log.h"
  37
  38 #ifdef __WXWINCE__
  39     #include <winreg.h>
  40     #include <ole2.h>
  41 #endif
  42
  43 #ifdef __WIN32__
  44     #if !defined(__GNUWIN32__) || wxUSE_NORLANDER_HEADERS
  45         #if wxCHECK_W32API_VERSION( 1, 0 )
  46             #include <windows.h>
  47         #endif
  48         #include <shlobj.h>            // for DROPFILES structure
  49     #endif
  50 #else
  51     #include <shellapi.h>
  52 #endif
  53
  54 #include "wx/dnd.h"
  55
  56 #include "wx/msw/ole/oleutils.h"
  57
  58 // ----------------------------------------------------------------------------
  59 // IDropTarget interface: forward all interesting things to wxDropTarget
  60 // (the name is unfortunate, but wx_I_DropTarget is not at all the same thing
  61 //  as wxDropTarget which is 'public' class, while this one is private)
  62 // ----------------------------------------------------------------------------
  63
  64 class wxIDropTarget : public IDropTarget
  65 {
  66 public:
  67     wxIDropTarget(wxDropTarget *p);
  68     virtual ~wxIDropTarget();
  69
  70     // accessors for wxDropTarget
  71     void SetHwnd(HWND hwnd) { m_hwnd = hwnd; }
  72
  73     // IDropTarget methods
  74     STDMETHODIMP DragEnter(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  75     STDMETHODIMP DragOver(DWORD, POINTL, LPDWORD);
  76     STDMETHODIMP DragLeave();
  77     STDMETHODIMP Drop(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  78
  79     DECLARE_IUNKNOWN_METHODS;
  80
  81 protected:
  82     IDataObject  *m_pIDataObject; // !NULL between DragEnter and DragLeave/Drop
  83     wxDropTarget *m_pTarget;      // the real target (we're just a proxy)
  84
  85     HWND          m_hwnd;         // window we're associated with
  86
  87     // get default drop effect for given keyboard flags
  88     static inline DWORD GetDropEffect(DWORD flags);
  89
  90     DECLARE_NO_COPY_CLASS(wxIDropTarget)
  91 };
  92
  93 // ----------------------------------------------------------------------------
  94 // private functions
  95 // ----------------------------------------------------------------------------
  96
  97 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect);
  98 static DWORD ConvertDragResultToEffect(wxDragResult result);
  99
 100 // ============================================================================
 101 // wxIDropTarget implementation
 102 // ============================================================================
 103
 104 // Name    : static wxIDropTarget::GetDropEffect
 105 // Purpose : determine the drop operation from keyboard/mouse state.
 106 // Returns : DWORD combined from DROPEFFECT_xxx constants
 107 // Params  : [in] DWORD flags       kbd & mouse flags as passed to
 108 //                                  IDropTarget methods
 109 // Notes   : We do "move" normally and "copy" if <Ctrl> is pressed,
 110 //           which is the standard behaviour (currently there is no
 111 //           way to redefine it)
 112 DWORD wxIDropTarget::GetDropEffect(DWORD flags)
 113 {
 114   return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
 115 }
 116
 117 wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
 118 {
 119   m_pTarget      = pTarget;
 120   m_pIDataObject = NULL;
 121 }
 122
 123 wxIDropTarget::~wxIDropTarget()
 124 {
 125 }
 126
 127 BEGIN_IID_TABLE(wxIDropTarget)
 128   ADD_IID(Unknown)
 129   ADD_IID(DropTarget)
 130 END_IID_TABLE;
 131
 132 IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
 133
 134 // Name    : wxIDropTarget::DragEnter
 135 // Purpose : Called when the mouse enters the window (dragging something)
 136 // Returns : S_OK
 137 // Params  : [in] IDataObject *pIDataSource : source data
 138 //           [in] DWORD        grfKeyState  : kbd & mouse state
 139 //           [in] POINTL       pt           : mouse coordinates
 140 //           [out]DWORD       *pdwEffect    : effect flag
 141 // Notes   :
 142 STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 143                                       DWORD        grfKeyState,
 144                                       POINTL       pt,
 145                                       DWORD       *pdwEffect)
 146 {
 147     wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
 148
 149     wxASSERT_MSG( m_pIDataObject == NULL,
 150                   _T("drop target must have data object") );
 151
 152     // show the list of formats supported by the source data object for the
 153     // debugging purposes, this is quite useful sometimes - please don't remove
 154 #if 0
 155     IEnumFORMATETC *penumFmt;
 156     if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
 157     {
 158         FORMATETC fmt;
 159         while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
 160         {
 161             wxLogDebug(_T("Drop source supports format %s"),
 162                        wxDataObject::GetFormatName(fmt.cfFormat));
 163         }
 164
 165         penumFmt->Release();
 166     }
 167     else
 168     {
 169         wxLogLastError(_T("IDataObject::EnumFormatEtc"));
 170     }
 171 #endif // 0
 172
 173     if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
 174         // we don't accept this kind of data
 175         *pdwEffect = DROPEFFECT_NONE;
 176
 177         return S_OK;
 178     }
 179
 180     // get hold of the data object
 181     m_pIDataObject = pIDataSource;
 182     m_pIDataObject->AddRef();
 183
 184     // we need client coordinates to pass to wxWin functions
 185     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 186     {
 187         wxLogLastError(wxT("ScreenToClient"));
 188     }
 189
 190     // give some visual feedback
 191     *pdwEffect = ConvertDragResultToEffect(
 192                     m_pTarget->OnEnter(pt.x, pt.y,
 193                         ConvertDragEffectToResult(GetDropEffect(grfKeyState))
 194                     )
 195                  );
 196
 197     return S_OK;
 198 }
 199
 200 // Name    : wxIDropTarget::DragOver
 201 // Purpose : Indicates that the mouse was moved inside the window represented
 202 //           by this drop target.
 203 // Returns : S_OK
 204 // Params  : [in] DWORD   grfKeyState     kbd & mouse state
 205 //           [in] POINTL  pt              mouse coordinates
 206 //           [out]LPDWORD pdwEffect       effect flag
 207 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 208 //           very efficient.
 209 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 210                                      POINTL  pt,
 211                                      LPDWORD pdwEffect)
 212 {
 213     // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 214
 215     wxDragResult result;
 216     if ( m_pIDataObject ) {
 217         result = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 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 occured?
 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(GetDropEffect(grfKeyState));
 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     HRESULT hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 334     if ( FAILED(hr) ) {
 335         wxLogApiError(wxT("CoLockObjectExternal"), hr);
 336         return FALSE;
 337     }
 338
 339     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 340     if ( FAILED(hr) ) {
 341         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 342
 343         wxLogApiError(wxT("RegisterDragDrop"), hr);
 344         return FALSE;
 345     }
 346
 347     // we will need the window handle for coords transformation later
 348     m_pIDropTarget->SetHwnd((HWND)hwnd);
 349
 350     return TRUE;
 351 }
 352
 353 void wxDropTarget::Revoke(WXHWND hwnd)
 354 {
 355     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 356
 357     if ( FAILED(hr) ) {
 358         wxLogApiError(wxT("RevokeDragDrop"), hr);
 359     }
 360
 361     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 362
 363     m_pIDropTarget->SetHwnd(0);
 364 }
 365
 366 // ----------------------------------------------------------------------------
 367 // base class pure virtuals
 368 // ----------------------------------------------------------------------------
 369
 370 // OnDrop() is called only if we previously returned TRUE from
 371 // IsAcceptedData(), so no need to check anything here
 372 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 373 {
 374     return TRUE;
 375 }
 376
 377 // copy the data from the data source to the target data object
 378 bool wxDropTarget::GetData()
 379 {
 380     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 381     if ( format == wxDF_INVALID ) {
 382         // this is strange because IsAcceptedData() succeeded previously!
 383         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 384
 385         return FALSE;
 386     }
 387
 388     STGMEDIUM stm;
 389     FORMATETC fmtMemory;
 390     fmtMemory.cfFormat  = format;
 391     fmtMemory.ptd       = NULL;
 392     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 393     fmtMemory.lindex    = -1;
 394     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 395
 396     bool rc = FALSE;
 397
 398     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 399     if ( SUCCEEDED(hr) ) {
 400         IDataObject *dataObject = m_dataObject->GetInterface();
 401
 402         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 403         if ( SUCCEEDED(hr) ) {
 404             rc = TRUE;
 405         }
 406         else {
 407             wxLogApiError(wxT("IDataObject::SetData()"), hr);
 408         }
 409     }
 410     else {
 411         wxLogApiError(wxT("IDataObject::GetData()"), hr);
 412     }
 413
 414     return rc;
 415 }
 416
 417 // ----------------------------------------------------------------------------
 418 // callbacks used by wxIDropTarget
 419 // ----------------------------------------------------------------------------
 420
 421 // we need a data source, so wxIDropTarget gives it to us using this function
 422 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 423 {
 424     m_pIDataSource = pIDataSource;
 425 }
 426
 427 // determine if we accept data of this type
 428 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 429 {
 430     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 431 }
 432
 433 // ----------------------------------------------------------------------------
 434 // helper functions
 435 // ----------------------------------------------------------------------------
 436
 437 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 438 {
 439     // this strucutre describes a data of any type (first field will be
 440     // changing) being passed through global memory block.
 441     static FORMATETC s_fmtMemory = {
 442         0,
 443         NULL,
 444         DVASPECT_CONTENT,
 445         -1,
 446         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 447     };
 448
 449     // get the list of supported formats
 450     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 451     wxDataFormat format;
 452     wxDataFormat *formats;
 453     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 454
 455     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 456
 457     // cycle through all supported formats
 458     size_t n;
 459     for ( n = 0; n < nFormats; n++ ) {
 460         s_fmtMemory.cfFormat = formats[n];
 461
 462         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 463         //     for file drag and drop (format == CF_HDROP)
 464         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 465             format = formats[n];
 466
 467             break;
 468         }
 469     }
 470
 471     if ( formats != &format ) {
 472         // free memory if we allocated it
 473         delete [] formats;
 474     }
 475
 476     return n < nFormats ? format : wxFormatInvalid;
 477 }
 478
 479 // ----------------------------------------------------------------------------
 480 // private functions
 481 // ----------------------------------------------------------------------------
 482
 483 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 484 {
 485     switch ( dwEffect ) {
 486         case DROPEFFECT_COPY:
 487             return wxDragCopy;
 488
 489         case DROPEFFECT_LINK:
 490             return wxDragLink;
 491
 492         case DROPEFFECT_MOVE:
 493             return wxDragMove;
 494
 495         default:
 496             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 497             // fall through
 498
 499         case DROPEFFECT_NONE:
 500             return wxDragNone;
 501     }
 502 }
 503
 504 static DWORD ConvertDragResultToEffect(wxDragResult result)
 505 {
 506     switch ( result ) {
 507         case wxDragCopy:
 508             return DROPEFFECT_COPY;
 509
 510         case wxDragLink:
 511             return DROPEFFECT_LINK;
 512
 513         case wxDragMove:
 514             return DROPEFFECT_MOVE;
 515
 516         default:
 517             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 518             // fall through
 519
 520         case wxDragNone:
 521             return DROPEFFECT_NONE;
 522     }
 523 }
 524
 525 #endif
 526  // wxUSE_DRAG_AND_DROP