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_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_cRef         = 0;
 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     wxLogDebug(wxT("IDropTarget::DragEnter"));
 146
 147     wxASSERT( m_pIDataObject == NULL );
 148
 149     if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
 150         // we don't accept this kind of data
 151         *pdwEffect = DROPEFFECT_NONE;
 152
 153         return S_OK;
 154     }
 155
 156     // get hold of the data object
 157     m_pIDataObject = pIDataSource;
 158     m_pIDataObject->AddRef();
 159
 160     // we need client coordinates to pass to wxWin functions
 161     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 162     {
 163         wxLogLastError(wxT("ScreenToClient"));
 164     }
 165
 166     // give some visual feedback
 167     *pdwEffect = ConvertDragResultToEffect(
 168                     m_pTarget->OnEnter(pt.x, pt.y,
 169                         ConvertDragEffectToResult(GetDropEffect(grfKeyState))
 170                     )
 171                  );
 172
 173     return S_OK;
 174 }
 175
 176 // Name    : wxIDropTarget::DragOver
 177 // Purpose : Indicates that the mouse was moved inside the window represented
 178 //           by this drop target.
 179 // Returns : S_OK
 180 // Params  : [in] DWORD   grfKeyState     kbd & mouse state
 181 //           [in] POINTL  pt              mouse coordinates
 182 //           [out]LPDWORD pdwEffect       effect flag
 183 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 184 //           very efficient.
 185 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 186                                      POINTL  pt,
 187                                      LPDWORD pdwEffect)
 188 {
 189     // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 190
 191     wxDragResult result;
 192     if ( m_pIDataObject ) {
 193         result = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 194     }
 195     else {
 196         // can't accept data anyhow normally
 197         result = wxDragNone;
 198     }
 199
 200     // we need client coordinates to pass to wxWin functions
 201     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 202     {
 203         wxLogLastError(wxT("ScreenToClient"));
 204     }
 205
 206     *pdwEffect = ConvertDragResultToEffect(
 207                     m_pTarget->OnDragOver(pt.x, pt.y, result)
 208                  );
 209
 210     return S_OK;
 211 }
 212
 213 // Name    : wxIDropTarget::DragLeave
 214 // Purpose : Informs the drop target that the operation has left its window.
 215 // Returns : S_OK
 216 // Notes   : good place to do any clean-up
 217 STDMETHODIMP wxIDropTarget::DragLeave()
 218 {
 219   wxLogDebug(wxT("IDropTarget::DragLeave"));
 220
 221   // remove the UI feedback
 222   m_pTarget->OnLeave();
 223
 224   // release the held object
 225   RELEASE_AND_NULL(m_pIDataObject);
 226
 227   return S_OK;
 228 }
 229
 230 // Name    : wxIDropTarget::Drop
 231 // Purpose : Instructs the drop target to paste data that was just now
 232 //           dropped on it.
 233 // Returns : S_OK
 234 // Params  : [in] IDataObject *pIDataSource     the data to paste
 235 //           [in] DWORD        grfKeyState      kbd & mouse state
 236 //           [in] POINTL       pt               where the drop occured?
 237 //           [ouy]DWORD       *pdwEffect        operation effect
 238 // Notes   :
 239 STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 240                                  DWORD        grfKeyState,
 241                                  POINTL       pt,
 242                                  DWORD       *pdwEffect)
 243 {
 244     wxLogDebug(wxT("IDropTarget::Drop"));
 245
 246     // TODO I don't know why there is this parameter, but so far I assume
 247     //      that it's the same we've already got in DragEnter
 248     wxASSERT( m_pIDataObject == pIDataSource );
 249
 250     // by default, nothing happens
 251     *pdwEffect = DROPEFFECT_NONE;
 252
 253     // we need client coordinates to pass to wxWin functions
 254     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 255     {
 256         wxLogLastError(wxT("ScreenToClient"));
 257     }
 258
 259     // first ask the drop target if it wants data
 260     if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
 261         // it does, so give it the data source
 262         m_pTarget->SetDataSource(pIDataSource);
 263
 264         // and now it has the data
 265         wxDragResult rc = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 266         rc = m_pTarget->OnData(pt.x, pt.y, rc);
 267         if ( wxIsDragResultOk(rc) ) {
 268             // operation succeeded
 269             *pdwEffect = ConvertDragResultToEffect(rc);
 270         }
 271         //else: *pdwEffect is already DROPEFFECT_NONE
 272     }
 273     //else: OnDrop() returned FALSE, no need to copy data
 274
 275     // release the held object
 276     RELEASE_AND_NULL(m_pIDataObject);
 277
 278     return S_OK;
 279 }
 280
 281 // ============================================================================
 282 // wxDropTarget implementation
 283 // ============================================================================
 284
 285 // ----------------------------------------------------------------------------
 286 // ctor/dtor
 287 // ----------------------------------------------------------------------------
 288
 289 wxDropTarget::wxDropTarget(wxDataObject *dataObj)
 290             : wxDropTargetBase(dataObj)
 291 {
 292     // create an IDropTarget implementation which will notify us about d&d
 293     // operations.
 294     m_pIDropTarget = new wxIDropTarget(this);
 295     m_pIDropTarget->AddRef();
 296 }
 297
 298 wxDropTarget::~wxDropTarget()
 299 {
 300     ReleaseInterface(m_pIDropTarget);
 301 }
 302
 303 // ----------------------------------------------------------------------------
 304 // [un]register drop handler
 305 // ----------------------------------------------------------------------------
 306
 307 bool wxDropTarget::Register(WXHWND hwnd)
 308 {
 309     HRESULT hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 310     if ( FAILED(hr) ) {
 311         wxLogApiError(wxT("CoLockObjectExternal"), hr);
 312         return FALSE;
 313     }
 314
 315     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 316     if ( FAILED(hr) ) {
 317         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 318
 319         wxLogApiError(wxT("RegisterDragDrop"), hr);
 320         return FALSE;
 321     }
 322
 323     // we will need the window handle for coords transformation later
 324     m_pIDropTarget->SetHwnd((HWND)hwnd);
 325
 326     return TRUE;
 327 }
 328
 329 void wxDropTarget::Revoke(WXHWND hwnd)
 330 {
 331     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 332
 333     if ( FAILED(hr) ) {
 334         wxLogApiError(wxT("RevokeDragDrop"), hr);
 335     }
 336
 337     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 338
 339     m_pIDropTarget->SetHwnd(0);
 340 }
 341
 342 // ----------------------------------------------------------------------------
 343 // base class pure virtuals
 344 // ----------------------------------------------------------------------------
 345
 346 // OnDrop() is called only if we previously returned TRUE from
 347 // IsAcceptedData(), so no need to check anything here
 348 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 349 {
 350     return TRUE;
 351 }
 352
 353 // copy the data from the data source to the target data object
 354 bool wxDropTarget::GetData()
 355 {
 356     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 357     if ( format == wxDF_INVALID ) {
 358         // this is strange because IsAcceptedData() succeeded previously!
 359         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 360
 361         return FALSE;
 362     }
 363
 364     STGMEDIUM stm;
 365     FORMATETC fmtMemory;
 366     fmtMemory.cfFormat  = format;
 367     fmtMemory.ptd       = NULL;
 368     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 369     fmtMemory.lindex    = -1;
 370     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 371
 372     bool rc = FALSE;
 373
 374     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 375     if ( SUCCEEDED(hr) ) {
 376         IDataObject *dataObject = m_dataObject->GetInterface();
 377
 378         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 379         if ( SUCCEEDED(hr) ) {
 380             rc = TRUE;
 381         }
 382         else {
 383             wxLogLastError(wxT("IDataObject::SetData()"));
 384         }
 385     }
 386     else {
 387         wxLogLastError(wxT("IDataObject::GetData()"));
 388     }
 389
 390     return rc;
 391 }
 392
 393 // ----------------------------------------------------------------------------
 394 // callbacks used by wxIDropTarget
 395 // ----------------------------------------------------------------------------
 396
 397 // we need a data source, so wxIDropTarget gives it to us using this function
 398 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 399 {
 400     m_pIDataSource = pIDataSource;
 401 }
 402
 403 // determine if we accept data of this type
 404 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 405 {
 406     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 407 }
 408
 409 // ----------------------------------------------------------------------------
 410 // helper functions
 411 // ----------------------------------------------------------------------------
 412
 413 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 414 {
 415     // this strucutre describes a data of any type (first field will be
 416     // changing) being passed through global memory block.
 417     static FORMATETC s_fmtMemory = {
 418         0,
 419         NULL,
 420         DVASPECT_CONTENT,
 421         -1,
 422         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 423     };
 424
 425     // get the list of supported formats
 426     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 427     wxDataFormat format;
 428         wxDataFormat *formats;
 429     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 430
 431     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 432
 433     // cycle through all supported formats
 434     size_t n;
 435     for ( n = 0; n < nFormats; n++ ) {
 436         s_fmtMemory.cfFormat = formats[n];
 437
 438         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 439         //     for file drag and drop (format == CF_HDROP)
 440         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 441             format = formats[n];
 442
 443             break;
 444         }
 445     }
 446
 447     if ( formats != &format ) {
 448         // free memory if we allocated it
 449         delete [] formats;
 450     }
 451
 452     return n < nFormats ? format : wxFormatInvalid;
 453 }
 454
 455 // ----------------------------------------------------------------------------
 456 // private functions
 457 // ----------------------------------------------------------------------------
 458
 459 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 460 {
 461     switch ( dwEffect ) {
 462         case DROPEFFECT_COPY:
 463             return wxDragCopy;
 464
 465         case DROPEFFECT_MOVE:
 466             return wxDragMove;
 467
 468         default:
 469             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 470             // fall through
 471
 472         case DROPEFFECT_NONE:
 473             return wxDragNone;
 474     }
 475 }
 476
 477 static DWORD ConvertDragResultToEffect(wxDragResult result)
 478 {
 479     switch ( result ) {
 480         case wxDragCopy:
 481             return DROPEFFECT_COPY;
 482
 483         case wxDragMove:
 484             return DROPEFFECT_MOVE;
 485
 486         default:
 487             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 488             // fall through
 489
 490         case wxDragNone:
 491             return DROPEFFECT_NONE;
 492     }
 493 }
 494
 495 #endif
 496  // wxUSE_DRAG_AND_DROP