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     #ifndef __GNUWIN32__
  39         #include <shlobj.h>            // for DROPFILES structure
  40     #endif
  41 #else
  42     #include <shellapi.h>
  43 #endif
  44
  45 #include "wx/dnd.h"
  46
  47 #ifndef __WIN32__
  48     #include <ole2.h>
  49     #include <olestd.h>
  50 #endif
  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     ~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);
  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)
 107 {
 108   return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
 109 }
 110
 111 wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
 112 {
 113   m_cRef         = 0;
 114   m_pTarget      = pTarget;
 115   m_pIDataObject = NULL;
 116 }
 117
 118 wxIDropTarget::~wxIDropTarget()
 119 {
 120 }
 121
 122 BEGIN_IID_TABLE(wxIDropTarget)
 123   ADD_IID(Unknown)
 124   ADD_IID(DropTarget)
 125 END_IID_TABLE;
 126
 127 IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
 128
 129 // Name    : wxIDropTarget::DragEnter
 130 // Purpose : Called when the mouse enters the window (dragging something)
 131 // Returns : S_OK
 132 // Params  : [in] IDataObject *pIDataSource : source data
 133 //           [in] DWORD        grfKeyState  : kbd & mouse state
 134 //           [in] POINTL       pt           : mouse coordinates
 135 //           [out]DWORD       *pdwEffect    : effect flag
 136 // Notes   :
 137 STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 138                                       DWORD        grfKeyState,
 139                                       POINTL       pt,
 140                                       DWORD       *pdwEffect)
 141 {
 142     wxLogDebug(wxT("IDropTarget::DragEnter"));
 143
 144     wxASSERT( m_pIDataObject == NULL );
 145
 146     if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
 147         // we don't accept this kind of data
 148         *pdwEffect = DROPEFFECT_NONE;
 149
 150         return S_OK;
 151     }
 152
 153     // get hold of the data object
 154     m_pIDataObject = pIDataSource;
 155     m_pIDataObject->AddRef();
 156
 157     // we need client coordinates to pass to wxWin functions
 158     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 159     {
 160         wxLogLastError("ScreenToClient");
 161     }
 162
 163     // give some visual feedback
 164     *pdwEffect = ConvertDragResultToEffect(
 165                     m_pTarget->OnEnter(pt.x, pt.y,
 166                         ConvertDragEffectToResult(GetDropEffect(grfKeyState))
 167                     )
 168                  );
 169
 170     return S_OK;
 171 }
 172
 173 // Name    : wxIDropTarget::DragOver
 174 // Purpose : Indicates that the mouse was moved inside the window represented
 175 //           by this drop target.
 176 // Returns : S_OK
 177 // Params  : [in] DWORD   grfKeyState     kbd & mouse state
 178 //           [in] POINTL  pt              mouse coordinates
 179 //           [out]LPDWORD pdwEffect       effect flag
 180 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 181 //           very efficient.
 182 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 183                                      POINTL  pt,
 184                                      LPDWORD pdwEffect)
 185 {
 186     // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 187
 188     wxDragResult result;
 189     if ( m_pIDataObject ) {
 190         result = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 191     }
 192     else {
 193         // can't accept data anyhow normally
 194         result = wxDragNone;
 195     }
 196
 197     // we need client coordinates to pass to wxWin functions
 198     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 199     {
 200         wxLogLastError("ScreenToClient");
 201     }
 202
 203     *pdwEffect = ConvertDragResultToEffect(
 204                     m_pTarget->OnDragOver(pt.x, pt.y, result)
 205                  );
 206
 207     return S_OK;
 208 }
 209
 210 // Name    : wxIDropTarget::DragLeave
 211 // Purpose : Informs the drop target that the operation has left its window.
 212 // Returns : S_OK
 213 // Notes   : good place to do any clean-up
 214 STDMETHODIMP wxIDropTarget::DragLeave()
 215 {
 216   wxLogDebug(wxT("IDropTarget::DragLeave"));
 217
 218   // remove the UI feedback
 219   m_pTarget->OnLeave();
 220
 221   // release the held object
 222   RELEASE_AND_NULL(m_pIDataObject);
 223
 224   return S_OK;
 225 }
 226
 227 // Name    : wxIDropTarget::Drop
 228 // Purpose : Instructs the drop target to paste data that was just now
 229 //           dropped on it.
 230 // Returns : S_OK
 231 // Params  : [in] IDataObject *pIDataSource     the data to paste
 232 //           [in] DWORD        grfKeyState      kbd & mouse state
 233 //           [in] POINTL       pt               where the drop occured?
 234 //           [ouy]DWORD       *pdwEffect        operation effect
 235 // Notes   :
 236 STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 237                                  DWORD        grfKeyState,
 238                                  POINTL       pt,
 239                                  DWORD       *pdwEffect)
 240 {
 241     wxLogDebug(wxT("IDropTarget::Drop"));
 242
 243     // TODO I don't know why there is this parameter, but so far I assume
 244     //      that it's the same we've already got in DragEnter
 245     wxASSERT( m_pIDataObject == pIDataSource );
 246
 247     // by default, nothing happens
 248     *pdwEffect = DROPEFFECT_NONE;
 249
 250     // we need client coordinates to pass to wxWin functions
 251     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 252     {
 253         wxLogLastError("ScreenToClient");
 254     }
 255
 256     // first ask the drop target if it wants data
 257     if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
 258         // it does, so give it the data source
 259         m_pTarget->SetDataSource(pIDataSource);
 260
 261         // and now it has the data
 262         wxDragResult rc = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 263         rc = m_pTarget->OnData(pt.x, pt.y, rc);
 264         if ( wxIsDragResultOk(rc) ) {
 265             // operation succeeded
 266             *pdwEffect = ConvertDragResultToEffect(rc);
 267         }
 268         //else: *pdwEffect is already DROPEFFECT_NONE
 269     }
 270     //else: OnDrop() returned FALSE, no need to copy data
 271
 272     // release the held object
 273     RELEASE_AND_NULL(m_pIDataObject);
 274
 275     return S_OK;
 276 }
 277
 278 // ============================================================================
 279 // wxDropTarget implementation
 280 // ============================================================================
 281
 282 // ----------------------------------------------------------------------------
 283 // ctor/dtor
 284 // ----------------------------------------------------------------------------
 285
 286 wxDropTarget::wxDropTarget(wxDataObject *dataObj)
 287             : wxDropTargetBase(dataObj)
 288 {
 289     // create an IDropTarget implementation which will notify us about d&d
 290     // operations.
 291     m_pIDropTarget = new wxIDropTarget(this);
 292     m_pIDropTarget->AddRef();
 293 }
 294
 295 wxDropTarget::~wxDropTarget()
 296 {
 297     ReleaseInterface(m_pIDropTarget);
 298 }
 299
 300 // ----------------------------------------------------------------------------
 301 // [un]register drop handler
 302 // ----------------------------------------------------------------------------
 303
 304 bool wxDropTarget::Register(WXHWND hwnd)
 305 {
 306     HRESULT hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 307     if ( FAILED(hr) ) {
 308         wxLogApiError("CoLockObjectExternal", hr);
 309         return FALSE;
 310     }
 311
 312     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 313     if ( FAILED(hr) ) {
 314         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 315
 316         wxLogApiError("RegisterDragDrop", hr);
 317         return FALSE;
 318     }
 319
 320     // we will need the window handle for coords transformation later
 321     m_pIDropTarget->SetHwnd((HWND)hwnd);
 322
 323     return TRUE;
 324 }
 325
 326 void wxDropTarget::Revoke(WXHWND hwnd)
 327 {
 328     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 329
 330     if ( FAILED(hr) ) {
 331         wxLogApiError("RevokeDragDrop", hr);
 332     }
 333
 334     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 335
 336     m_pIDropTarget->SetHwnd(0);
 337 }
 338
 339 // ----------------------------------------------------------------------------
 340 // base class pure virtuals
 341 // ----------------------------------------------------------------------------
 342
 343 // OnDrop() is called only if we previously returned TRUE from
 344 // IsAcceptedData(), so no need to check anything here
 345 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 346 {
 347     return TRUE;
 348 }
 349
 350 // copy the data from the data source to the target data object
 351 bool wxDropTarget::GetData()
 352 {
 353     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 354     if ( format == wxDF_INVALID ) {
 355         // this is strange because IsAcceptedData() succeeded previously!
 356         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 357
 358         return FALSE;
 359     }
 360
 361     STGMEDIUM stm;
 362     FORMATETC fmtMemory;
 363     fmtMemory.cfFormat  = format;
 364     fmtMemory.ptd       = NULL;
 365     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 366     fmtMemory.lindex    = -1;
 367     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 368
 369     bool rc = FALSE;
 370
 371     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 372     if ( SUCCEEDED(hr) ) {
 373         IDataObject *dataObject = m_dataObject->GetInterface();
 374
 375         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 376         if ( SUCCEEDED(hr) ) {
 377             rc = TRUE;
 378         }
 379         else {
 380             wxLogLastError("IDataObject::SetData()");
 381         }
 382     }
 383     else {
 384         wxLogLastError("IDataObject::GetData()");
 385     }
 386
 387     return rc;
 388 }
 389
 390 // ----------------------------------------------------------------------------
 391 // callbacks used by wxIDropTarget
 392 // ----------------------------------------------------------------------------
 393
 394 // we need a data source, so wxIDropTarget gives it to us using this function
 395 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 396 {
 397     m_pIDataSource = pIDataSource;
 398 }
 399
 400 // determine if we accept data of this type
 401 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 402 {
 403     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 404 }
 405
 406 // ----------------------------------------------------------------------------
 407 // helper functions
 408 // ----------------------------------------------------------------------------
 409
 410 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 411 {
 412     // this strucutre describes a data of any type (first field will be
 413     // changing) being passed through global memory block.
 414     static FORMATETC s_fmtMemory = {
 415         0,
 416         NULL,
 417         DVASPECT_CONTENT,
 418         -1,
 419         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 420     };
 421
 422     // get the list of supported formats
 423     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 424     wxDataFormat format, *formats;
 425     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 426
 427     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 428
 429     // cycle through all supported formats
 430     size_t n;
 431     for ( n = 0; n < nFormats; n++ ) {
 432         s_fmtMemory.cfFormat = formats[n];
 433
 434         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 435         //     for file drag and drop (format == CF_HDROP)
 436         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 437             format = formats[n];
 438
 439             break;
 440         }
 441     }
 442
 443     if ( formats != &format ) {
 444         // free memory if we allocated it
 445         delete [] formats;
 446     }
 447
 448     return n < nFormats ? format : wxFormatInvalid;
 449 }
 450
 451 // ----------------------------------------------------------------------------
 452 // private functions
 453 // ----------------------------------------------------------------------------
 454
 455 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 456 {
 457     switch ( dwEffect ) {
 458         case DROPEFFECT_COPY:
 459             return wxDragCopy;
 460
 461         case DROPEFFECT_MOVE:
 462             return wxDragMove;
 463
 464         default:
 465             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 466             // fall through
 467
 468         case DROPEFFECT_NONE:
 469             return wxDragNone;
 470     }
 471 }
 472
 473 static DWORD ConvertDragResultToEffect(wxDragResult result)
 474 {
 475     switch ( result ) {
 476         case wxDragCopy:
 477             return DROPEFFECT_COPY;
 478
 479         case wxDragMove:
 480             return DROPEFFECT_MOVE;
 481
 482         default:
 483             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 484             // fall through
 485
 486         case wxDragNone:
 487             return DROPEFFECT_NONE;
 488     }
 489 }
 490
 491 #endif
 492  // wxUSE_DRAG_AND_DROP