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/dataobj.h"
  46 #include "wx/msw/ole/droptgt.h"
  47
  48 #ifndef __WIN32__
  49     #include <ole2.h>
  50     #include <olestd.h>
  51 #endif
  52
  53 #include "wx/msw/ole/oleutils.h"
  54
  55 // ----------------------------------------------------------------------------
  56 // IDropTarget interface: forward all interesting things to wxDropTarget
  57 // (the name is unfortunate, but wx_I_DropTarget is not at all the same thing
  58 //  as wxDropTarget which is 'public' class, while this one is private)
  59 // ----------------------------------------------------------------------------
  60
  61 class wxIDropTarget : public IDropTarget
  62 {
  63 public:
  64   wxIDropTarget(wxDropTarget *p);
  65  ~wxIDropTarget();
  66
  67   // IDropTarget methods
  68   STDMETHODIMP DragEnter(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  69   STDMETHODIMP DragOver(DWORD, POINTL, LPDWORD);
  70   STDMETHODIMP DragLeave(void);
  71   STDMETHODIMP Drop(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  72
  73   // we assume that if QueryGetData() returns S_OK, than we can really get data
  74   // in this format, so we remember here the format for which QueryGetData()
  75   // succeeded
  76   void SetSupportedFormat(wxDataFormat cfFormat) { m_cfFormat = cfFormat; }
  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   wxDataFormat   m_cfFormat;      // the format in which to ask for data
  85
  86 private:
  87   static inline DWORD GetDropEffect(DWORD flags);
  88 };
  89
  90 // ============================================================================
  91 // wxIDropTarget implementation
  92 // ============================================================================
  93
  94 // Name    : static wxDropTarget::GetDropEffect
  95 // Purpose : determine the drop operation from keyboard/mouse state.
  96 // Returns : DWORD combined from DROPEFFECT_xxx constants
  97 // Params  : [in] DWORD flags       kbd & mouse flags as passed to
  98 //                                  IDropTarget methods
  99 // Notes   : We do "move" normally and "copy" if <Ctrl> is pressed,
 100 //           which is the standard behaviour (currently there is no
 101 //           way to redefine it)
 102 DWORD wxIDropTarget::GetDropEffect(DWORD flags)
 103 {
 104   return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
 105 }
 106
 107 wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
 108 {
 109   m_cRef         = 0;
 110   m_pTarget      = pTarget;
 111   m_cfFormat     = wxDF_INVALID;
 112   m_pIDataObject = NULL;
 113 }
 114
 115 wxIDropTarget::~wxIDropTarget()
 116 {
 117 }
 118
 119 BEGIN_IID_TABLE(wxIDropTarget)
 120   ADD_IID(Unknown)
 121   ADD_IID(DropTarget)
 122 END_IID_TABLE;
 123
 124 IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
 125
 126 // Name    : wxIDropTarget::DragEnter
 127 // Purpose : Called when the mouse enters the window (dragging something)
 128 // Returns : S_OK
 129 // Params  : [in] IDataObject *pIDataSource : source data
 130 //           [in] DWORD        grfKeyState  : kbd & mouse state
 131 //           [in] POINTL       pt           : mouse coordinates
 132 //           [out]DWORD       *pdwEffect    : effect flag
 133 // Notes   :
 134 STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 135                                       DWORD        grfKeyState,
 136                                       POINTL       pt,
 137                                       DWORD       *pdwEffect)
 138 {
 139   wxLogDebug("IDropTarget::DragEnter");
 140
 141   wxASSERT( m_pIDataObject == NULL );
 142
 143   if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
 144     // we don't accept this kind of data
 145     *pdwEffect = DROPEFFECT_NONE;
 146
 147     return S_OK;
 148   }
 149
 150   // TODO should check the point also?
 151
 152   *pdwEffect = GetDropEffect(grfKeyState);
 153
 154   // get hold of the data object
 155   m_pIDataObject = pIDataSource;
 156   m_pIDataObject->AddRef();
 157
 158   // give some visual feedback
 159   m_pTarget->OnEnter();
 160
 161   return S_OK;
 162 }
 163
 164 // Name    : wxIDropTarget::DragOver
 165 // Purpose : Indicates that the mouse was moved inside the window represented
 166 //           by this drop target.
 167 // Returns : S_OK
 168 // Params  : [in] DWORD   grfKeyState     kbd & mouse state
 169 //           [in] POINTL  pt              mouse coordinates
 170 //           [out]LPDWORD pdwEffect       effect flag
 171 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 172 //           very efficient.
 173 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 174                                      POINTL  pt,
 175                                      LPDWORD pdwEffect)
 176 {
 177   // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 178
 179   *pdwEffect = m_pIDataObject == NULL ? DROPEFFECT_NONE
 180                                       : GetDropEffect(grfKeyState);
 181   return S_OK;
 182 }
 183
 184 // Name    : wxIDropTarget::DragLeave
 185 // Purpose : Informs the drop target that the operation has left its window.
 186 // Returns : S_OK
 187 // Notes   : good place to do any clean-up
 188 STDMETHODIMP wxIDropTarget::DragLeave()
 189 {
 190   wxLogDebug("IDropTarget::DragLeave");
 191
 192   // remove the UI feedback
 193   m_pTarget->OnLeave();
 194
 195   // release the held object
 196   RELEASE_AND_NULL(m_pIDataObject);
 197
 198   return S_OK;
 199 }
 200
 201 // Name    : wxIDropTarget::Drop
 202 // Purpose : Instructs the drop target to paste data that was just now
 203 //           dropped on it.
 204 // Returns : S_OK
 205 // Params  : [in] IDataObject *pIDataSource     the data to paste
 206 //           [in] DWORD        grfKeyState      kbd & mouse state
 207 //           [in] POINTL       pt               where the drop occured?
 208 //           [ouy]DWORD       *pdwEffect        operation effect
 209 // Notes   :
 210 STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 211                                  DWORD        grfKeyState,
 212                                  POINTL       pt,
 213                                  DWORD       *pdwEffect)
 214 {
 215   wxLogDebug("IDropTarget::Drop");
 216
 217   // TODO I don't know why there is this parameter, but so far I assume
 218   //      that it's the same we've already got in DragEnter
 219   wxASSERT( m_pIDataObject == pIDataSource );
 220
 221   STGMEDIUM stm;
 222   *pdwEffect = DROPEFFECT_NONE;
 223
 224   // should be set by SetSupportedFormat() call
 225   wxASSERT( m_cfFormat != wxDF_INVALID );
 226
 227   FORMATETC fmtMemory;
 228   fmtMemory.cfFormat  = m_cfFormat;
 229   fmtMemory.ptd       = NULL;
 230   fmtMemory.dwAspect  = DVASPECT_CONTENT;
 231   fmtMemory.lindex    = -1;
 232   fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 233
 234   HRESULT hr = pIDataSource->GetData(&fmtMemory, &stm);
 235   if ( SUCCEEDED(hr) ) {
 236     if ( stm.hGlobal != NULL ) {
 237       if ( m_pTarget->OnDrop(pt.x, pt.y, GlobalLock(stm.hGlobal)) )
 238         *pdwEffect = GetDropEffect(grfKeyState);
 239       //else: DROPEFFECT_NONE
 240
 241       GlobalUnlock(stm.hGlobal);
 242       ReleaseStgMedium(&stm);
 243     }
 244   }
 245   else
 246   {
 247     // wxLogApiError("GetData", hr);
 248   }
 249
 250   // release the held object
 251   RELEASE_AND_NULL(m_pIDataObject);
 252
 253   return S_OK;
 254 }
 255
 256 // ============================================================================
 257 // wxDropTarget implementation
 258 // ============================================================================
 259
 260 // ----------------------------------------------------------------------------
 261 // ctor/dtor
 262 // ----------------------------------------------------------------------------
 263
 264 wxDropTarget::wxDropTarget()
 265 {
 266   // create an IDropTarget implementation which will notify us about
 267   // d&d operations.
 268   m_pIDropTarget = new wxIDropTarget(this);
 269   m_pIDropTarget->AddRef();
 270 }
 271
 272 wxDropTarget::~wxDropTarget()
 273 {
 274   ReleaseInterface(m_pIDropTarget);
 275 }
 276
 277 // ----------------------------------------------------------------------------
 278 // [un]register drop handler
 279 // ----------------------------------------------------------------------------
 280
 281 bool wxDropTarget::Register(WXHWND hwnd)
 282 {
 283   HRESULT hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 284   if ( FAILED(hr) ) {
 285     wxLogApiError("CoLockObjectExternal", hr);
 286     return FALSE;
 287   }
 288
 289   hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 290   if ( FAILED(hr) ) {
 291     ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 292
 293     wxLogApiError("RegisterDragDrop", hr);
 294     return FALSE;
 295   }
 296
 297   return TRUE;
 298 }
 299
 300 void wxDropTarget::Revoke(WXHWND hwnd)
 301 {
 302   HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 303
 304   if ( FAILED(hr) ) {
 305     wxLogApiError("RevokeDragDrop", hr);
 306   }
 307
 308   ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 309 }
 310
 311 // ----------------------------------------------------------------------------
 312 // determine if we accept data of this type
 313 // ----------------------------------------------------------------------------
 314 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 315 {
 316   // this strucutre describes a data of any type (first field will be
 317   // changing) being passed through global memory block.
 318   static FORMATETC s_fmtMemory = {
 319     0,
 320     NULL,
 321     DVASPECT_CONTENT,
 322     -1,
 323     TYMED_HGLOBAL
 324   };
 325
 326   // cycle thorugh all supported formats
 327   for ( size_t n = 0; n < GetFormatCount(); n++ ) {
 328     s_fmtMemory.cfFormat = GetFormat(n);
 329     // NB: don't use SUCCEEDED macro here: QueryGetData returns 1 (whatever it
 330     //     means) for file drag and drop
 331     if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 332       // remember this format: we'll later ask for data in it
 333       m_pIDropTarget->SetSupportedFormat((unsigned int)s_fmtMemory.cfFormat);
 334       return TRUE;
 335     }
 336   }
 337
 338   return FALSE;
 339 }
 340
 341 // ============================================================================
 342 // wxTextDropTarget
 343 // ============================================================================
 344
 345 bool wxTextDropTarget::OnDrop(long x, long y, const void *pData)
 346 {
 347   return OnDropText(x, y, (const char *)pData);
 348 }
 349
 350 size_t wxTextDropTarget::GetFormatCount() const
 351 {
 352   return 1;
 353 }
 354
 355 wxDataFormat wxTextDropTarget::GetFormat(size_t WXUNUSED(n)) const
 356 {
 357   return wxDF_TEXT;
 358 }
 359
 360 // ============================================================================
 361 // wxFileDropTarget
 362 // ============================================================================
 363
 364 bool wxFileDropTarget::OnDrop(long x, long y, const void *pData)
 365 {
 366   // the documentation states that the first member of DROPFILES structure
 367   // is a "DWORD offset of double NUL terminated file list". What they mean by
 368   // this (I wonder if you see it immediately) is that the list starts at
 369   // ((char *)&(pDropFiles.pFiles)) + pDropFiles.pFiles. We're also advised to
 370   // use DragQueryFile to work with this structure, but not told where and how
 371   // to get HDROP.
 372   HDROP hdrop = (HDROP)pData;   // NB: it works, but I'm not sure about it
 373
 374   // get number of files (magic value -1)
 375   UINT nFiles = ::DragQueryFile(hdrop, (unsigned)-1, NULL, 0u);
 376
 377   // for each file get the length, allocate memory and then get the name
 378   char **aszFiles = new char *[nFiles];
 379   UINT len, n;
 380   for ( n = 0; n < nFiles; n++ ) {
 381     // +1 for terminating NUL
 382     len = ::DragQueryFile(hdrop, n, NULL, 0) + 1;
 383
 384     aszFiles[n] = new char[len];
 385
 386     UINT len2 = ::DragQueryFile(hdrop, n, aszFiles[n], len);
 387     if ( len2 != len - 1 ) {
 388       wxLogDebug("In wxFileDropTarget::OnDrop DragQueryFile returned %d "
 389                  "characters, %d expected.", len2, len - 1);
 390     }
 391   }
 392
 393   bool bResult = OnDropFiles(x, y, nFiles, (const char**) aszFiles);
 394
 395   // free memory
 396   for ( n = 0; n < nFiles; n++ ) {
 397     delete [] aszFiles[n];
 398   }
 399   delete [] aszFiles;
 400
 401   return bResult;
 402 }
 403
 404 size_t wxFileDropTarget::GetFormatCount() const
 405 {
 406   return 1;
 407 }
 408
 409 wxDataFormat wxFileDropTarget::GetFormat(size_t WXUNUSED(n)) const
 410 {
 411 #ifdef __WIN32__
 412   return wxDF_FILENAME;
 413 #else
 414   // TODO: how to implement this in WIN16?
 415   return wxDF_TEXT;
 416 #endif
 417 }
 418
 419 #endif
 420  // wxUSE_DRAG_AND_DROP