dll/shellext/acppage/CLayerUIPropPage.cpp

   1 /*
   2  * PROJECT:     ReactOS Compatibility Layer Shell Extension
   3  * LICENSE:     GPL-2.0+ (https://spdx.org/licenses/GPL-2.0+)
   4  * PURPOSE:     CLayerUIPropPage implementation
   5  * COPYRIGHT:   Copyright 2015-2017 Mark Jansen (mark.jansen@reactos.org)
   6  */
   7
   8 #include "precomp.h"
   9
  10 #include <shlwapi.h>
  11 #include <shellapi.h>
  12 #include <shellutils.h>
  13 #include <strsafe.h>
  14 #include <apphelp.h>
  15 #include <windowsx.h>
  16 #include <sfc.h>
  17
  18 const GUID CLSID_CLayerUIPropPage = { 0x513D916F, 0x2A8E, 0x4F51, { 0xAE, 0xAB, 0x0C, 0xBC, 0x76, 0xFB, 0x1A, 0xF8 } };
  19 #define ACP_WNDPROP L"{513D916F-2A8E-4F51-AEAB-0CBC76FB1AF8}.Prop"
  20
  21 #define GPLK_USER 1
  22 #define GPLK_MACHINE 2
  23 #define MAX_LAYER_LENGTH 256
  24
  25 static struct {
  26     const PCWSTR Display;
  27     const PCWSTR Name;
  28 } g_CompatModes[] = {
  29     { L"Windows 95", L"WIN95" },
  30     { L"Windows 98/ME", L"WIN98" },
  31     { L"Windows NT 4.0 (SP5)", L"NT4SP5" },
  32     { L"Windows 2000", L"WIN2000" },
  33     { L"Windows XP (SP2)", L"WINXPSP2" },
  34     { L"Windows XP (SP3)", L"WINXPSP3" },
  35     { L"Windows Server 2003 (SP1)", L"WINSRV03SP1" },
  36 #if 0
  37     { L"Windows Server 2008 (SP1)", L"WINSRV08SP1" },
  38     { L"Windows Vista", L"VISTARTM" },
  39     { L"Windows Vista (SP1)", L"VISTASP1" },
  40     { L"Windows Vista (SP2)", L"VISTASP2" },
  41     { L"Windows 7", L"WIN7RTM" },
  42 #endif
  43     { NULL, NULL }
  44 };
  45
  46 static struct {
  47     const PCWSTR Name;
  48     DWORD Id;
  49 } g_Layers[] = {
  50     { L"256COLOR", IDC_CHKRUNIN256COLORS },
  51     { L"640X480", IDC_CHKRUNIN640480RES },
  52     { L"DISABLETHEMES", IDC_CHKDISABLEVISUALTHEMES },
  53 #if 0
  54     { L"DISABLEDWM", IDC_??, TRUE },
  55     { L"HIGHDPIAWARE", IDC_??, TRUE },
  56     { L"RUNASADMIN", IDC_??, TRUE },
  57 #endif
  58     { NULL, 0 }
  59 };
  60
  61 static const WCHAR* g_AllowedExtensions[] = {
  62     L".exe",
  63     L".msi",
  64     L".pif",
  65     L".bat",
  66     L".cmd",
  67     0
  68 };
  69
  70
  71 void ACDBG_FN(PCSTR FunctionName, PCWSTR Format, ...)
  72 {
  73     WCHAR Buffer[512];
  74     WCHAR* Current = Buffer;
  75     size_t Length = _countof(Buffer);
  76
  77     StringCchPrintfExW(Current, Length, &Current, &Length, STRSAFE_NULL_ON_FAILURE, L"[%-20S] ", FunctionName);
  78     va_list ArgList;
  79     va_start(ArgList, Format);
  80     StringCchVPrintfExW(Current, Length, &Current, &Length, STRSAFE_NULL_ON_FAILURE, Format, ArgList);
  81     va_end(ArgList);
  82     OutputDebugStringW(Buffer);
  83 }
  84
  85 #define ACDBG(fmt, ...)  ACDBG_FN(__FUNCTION__, fmt, ##__VA_ARGS__ )
  86
  87
  88
  89 CLayerUIPropPage::CLayerUIPropPage()
  90 : m_IsSfcProtected(FALSE)
  91 , m_AllowPermLayer(FALSE)
  92 , m_LayerQueryFlags(GPLK_USER)  /* TODO: When do we read from HKLM? */
  93 , m_RegistryOSMode(0)
  94 , m_OSMode(0)
  95 , m_RegistryEnabledLayers(0)
  96 , m_EnabledLayers(0)
  97 {
  98 }
  99
 100 CLayerUIPropPage::~CLayerUIPropPage()
 101 {
 102 }
 103
 104 HRESULT CLayerUIPropPage::InitFile(PCWSTR Filename)
 105 {
 106     CString ExpandedFilename;
 107     DWORD dwRequired = ExpandEnvironmentStringsW(Filename, NULL, 0);
 108     if (dwRequired > 0)
 109     {
 110         LPWSTR Buffer = ExpandedFilename.GetBuffer(dwRequired);
 111         DWORD dwReturned = ExpandEnvironmentStringsW(Filename, Buffer, dwRequired);
 112         if (dwRequired == dwReturned)
 113         {
 114             ExpandedFilename.ReleaseBufferSetLength(dwReturned - 1);
 115             ACDBG(L"Expanded '%s' => '%s'\r\n", Filename, (PCWSTR)ExpandedFilename);
 116         }
 117         else
 118         {
 119             ExpandedFilename.ReleaseBufferSetLength(0);
 120             ExpandedFilename = Filename;
 121             ACDBG(L"Failed during expansion '%s'\r\n", Filename);
 122         }
 123     }
 124     else
 125     {
 126         ACDBG(L"Failed to expand '%s'\r\n", Filename);
 127         ExpandedFilename = Filename;
 128     }
 129     PCWSTR pwszExt = PathFindExtensionW(ExpandedFilename);
 130     if (!pwszExt)
 131     {
 132         ACDBG(L"Failed to find an extension: '%s'\r\n", (PCWSTR)ExpandedFilename);
 133         return E_FAIL;
 134     }
 135     if (!wcsicmp(pwszExt, L".lnk"))
 136     {
 137         WCHAR Buffer[MAX_PATH];
 138         if (!GetExeFromLnk(ExpandedFilename, Buffer, _countof(Buffer)))
 139         {
 140             ACDBG(L"Failed to read link target from: '%s'\r\n", (PCWSTR)ExpandedFilename);
 141             return E_FAIL;
 142         }
 143         if (!wcsicmp(Buffer, ExpandedFilename))
 144         {
 145             ACDBG(L"Link redirects to itself: '%s'\r\n", (PCWSTR)ExpandedFilename);
 146             return E_FAIL;
 147         }
 148         return InitFile(Buffer);
 149     }
 150
 151     CString tmp;
 152     if (tmp.GetEnvironmentVariable(L"SystemRoot"))
 153     {
 154         tmp += L"\\System32";
 155         if (ExpandedFilename.GetLength() >= tmp.GetLength() &&
 156             ExpandedFilename.Left(tmp.GetLength()).MakeLower() == tmp.MakeLower())
 157         {
 158             ACDBG(L"Ignoring System32: %s\r\n", (PCWSTR)ExpandedFilename);
 159             return E_FAIL;
 160         }
 161         tmp.GetEnvironmentVariable(L"SystemRoot");
 162         tmp += L"\\WinSxs";
 163         if (ExpandedFilename.GetLength() >= tmp.GetLength() &&
 164             ExpandedFilename.Left(tmp.GetLength()).MakeLower() == tmp.MakeLower())
 165         {
 166             ACDBG(L"Ignoring WinSxs: %s\r\n", (PCWSTR)ExpandedFilename);
 167             return E_FAIL;
 168         }
 169     }
 170
 171     for (size_t n = 0; g_AllowedExtensions[n]; ++n)
 172     {
 173         if (!wcsicmp(g_AllowedExtensions[n], pwszExt))
 174         {
 175             m_Filename = ExpandedFilename;
 176             ACDBG(L"Got: %s\r\n", (PCWSTR)ExpandedFilename);
 177             m_IsSfcProtected = SfcIsFileProtected(NULL, m_Filename);
 178             m_AllowPermLayer = AllowPermLayer(ExpandedFilename);
 179             return S_OK;
 180         }
 181     }
 182     ACDBG(L"Extension not included: '%s'\r\n", pwszExt);
 183     return E_FAIL;
 184 }
 185
 186 static BOOL GetLayerInfo(PCWSTR Filename, DWORD QueryFlags, PDWORD OSMode, PDWORD Enabledlayers, CSimpleArray<CString>& customLayers)
 187 {
 188     WCHAR wszLayers[MAX_LAYER_LENGTH] = { 0 };
 189     DWORD dwBytes = sizeof(wszLayers);
 190
 191     *OSMode = *Enabledlayers = 0;
 192     customLayers.RemoveAll();
 193     if (!SdbGetPermLayerKeys(Filename, wszLayers, &dwBytes, QueryFlags))
 194         return FALSE;
 195
 196     for (PWCHAR Layer = wcstok(wszLayers, L" "); Layer; Layer = wcstok(NULL, L" "))
 197     {
 198         size_t n;
 199         for (n = 0; g_Layers[n].Name; ++n)
 200         {
 201             if (!wcsicmp(g_Layers[n].Name, Layer))
 202             {
 203                 *Enabledlayers |= (1<<n);
 204                 break;
 205             }
 206         }
 207         /* Did we find it? */
 208         if (g_Layers[n].Name)
 209             continue;
 210
 211         for (n = 0; g_CompatModes[n].Name; ++n)
 212         {
 213             if (!wcsicmp(g_CompatModes[n].Name, Layer))
 214             {
 215                 *OSMode = n+1;
 216                 break;
 217             }
 218         }
 219         /* Did we find it? */
 220         if (g_CompatModes[n].Name)
 221             continue;
 222
 223         /* Must be a 'custom' layer */
 224         customLayers.Add(Layer);
 225     }
 226     return TRUE;
 227 }
 228
 229 int CLayerUIPropPage::OnSetActive()
 230 {
 231     if (!GetLayerInfo(m_Filename, m_LayerQueryFlags, &m_RegistryOSMode, &m_RegistryEnabledLayers, m_RegistryCustomLayers))
 232         m_RegistryOSMode = m_RegistryEnabledLayers = 0;
 233
 234     for (size_t n = 0; g_Layers[n].Name; ++n)
 235         CheckDlgButton(g_Layers[n].Id, (m_RegistryEnabledLayers & (1<<n)) ? BST_CHECKED : BST_UNCHECKED);
 236
 237     CheckDlgButton(IDC_CHKRUNCOMPATIBILITY, m_RegistryOSMode ? BST_CHECKED : BST_UNCHECKED);
 238
 239     if (m_RegistryOSMode)
 240         ComboBox_SetCurSel(GetDlgItem(IDC_COMPATIBILITYMODE), m_RegistryOSMode-1);
 241
 242     m_CustomLayers = m_RegistryCustomLayers;
 243
 244     /* TODO: visualize 'custom' layers! */
 245
 246     UpdateControls();
 247
 248     return 0;
 249 }
 250
 251
 252 static BOOL ArrayEquals(const CSimpleArray<CString>& lhs, const CSimpleArray<CString>& rhs)
 253 {
 254     if (lhs.GetSize() != rhs.GetSize())
 255         return FALSE;
 256
 257     for (int n = 0; n < lhs.GetSize(); ++n)
 258     {
 259         if (lhs[n] != rhs[n])
 260             return FALSE;
 261     }
 262     return TRUE;
 263 }
 264
 265 BOOL CLayerUIPropPage::HasChanges() const
 266 {
 267     if (m_RegistryEnabledLayers != m_EnabledLayers)
 268         return TRUE;
 269
 270     if (m_RegistryOSMode != m_OSMode)
 271         return TRUE;
 272
 273     if (!ArrayEquals(m_RegistryCustomLayers, m_CustomLayers))
 274         return TRUE;
 275
 276     return FALSE;
 277 }
 278
 279 int CLayerUIPropPage::OnApply()
 280 {
 281     if (HasChanges())
 282     {
 283         BOOL bMachine = m_LayerQueryFlags == GPLK_MACHINE;
 284
 285         for (size_t n = 0; g_CompatModes[n].Name; ++n)
 286             SetPermLayerState(m_Filename, g_CompatModes[n].Name, 0, bMachine, (n+1) == m_OSMode);
 287
 288         for (size_t n = 0; g_Layers[n].Name; ++n)
 289         {
 290             SetPermLayerState(m_Filename, g_Layers[n].Name, 0, bMachine, ((1<<n) & m_EnabledLayers) != 0);
 291         }
 292
 293         /* Disable all old values */
 294         for (int j = 0; j < m_RegistryCustomLayers.GetSize(); j++)
 295         {
 296             SetPermLayerState(m_Filename, m_RegistryCustomLayers[j].GetString(), 0, bMachine, FALSE);
 297         }
 298
 299         /* Enable all new values */
 300         for (int j = 0; j < m_CustomLayers.GetSize(); j++)
 301         {
 302             SetPermLayerState(m_Filename, m_CustomLayers[j].GetString(), 0, bMachine, TRUE);
 303         }
 304
 305         SHChangeNotify(SHCNE_UPDATEITEM, SHCNF_PATHW, (PCWSTR)m_Filename, NULL);
 306     }
 307
 308     return PSNRET_NOERROR;
 309 }
 310
 311 LRESULT CLayerUIPropPage::OnInitDialog(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL &bHandled)
 312 {
 313     HWND cboMode = GetDlgItem(IDC_COMPATIBILITYMODE);
 314     for (size_t n = 0; g_CompatModes[n].Display; ++n)
 315         ComboBox_AddString(cboMode, g_CompatModes[n].Display);
 316     ComboBox_SetCurSel(cboMode, 5);
 317
 318     CComBSTR explanation;
 319     if (!m_AllowPermLayer)
 320     {
 321         explanation.LoadString(g_hModule, IDS_FAILED_NETWORK);
 322         DisableControls();
 323         ACDBG(L"AllowPermLayer returned FALSE\r\n");
 324     }
 325     else if (m_IsSfcProtected)
 326     {
 327         explanation.LoadString(g_hModule, IDS_FAILED_PROTECTED);
 328         DisableControls();
 329         ACDBG(L"Protected OS file\r\n");
 330     }
 331     else
 332     {
 333         return TRUE;
 334     }
 335     SetDlgItemTextW(IDC_EXPLANATION, explanation);
 336     return TRUE;
 337 }
 338
 339 INT_PTR CLayerUIPropPage::DisableControls()
 340 {
 341     ::EnableWindow(GetDlgItem(IDC_COMPATIBILITYMODE), 0);
 342     ::EnableWindow(GetDlgItem(IDC_CHKRUNCOMPATIBILITY), 0);
 343     for (size_t n = 0; g_Layers[n].Name; ++n)
 344         ::EnableWindow(GetDlgItem(g_Layers[n].Id), 0);
 345     ::EnableWindow(GetDlgItem(IDC_EDITCOMPATIBILITYMODES), 0);
 346     return TRUE;
 347 }
 348
 349 void CLayerUIPropPage::UpdateControls()
 350 {
 351     m_OSMode = 0, m_EnabledLayers = 0;
 352     BOOL ModeEnabled = IsDlgButtonChecked(IDC_CHKRUNCOMPATIBILITY);
 353     if (ModeEnabled)
 354         m_OSMode = ComboBox_GetCurSel(GetDlgItem(IDC_COMPATIBILITYMODE))+1;
 355     ::EnableWindow(GetDlgItem(IDC_COMPATIBILITYMODE), ModeEnabled);
 356
 357     for (size_t n = 0; g_Layers[n].Name; ++n)
 358     {
 359         m_EnabledLayers |= IsDlgButtonChecked(g_Layers[n].Id) ? (1<<n) : 0;
 360         ::ShowWindow(GetDlgItem(g_Layers[n].Id), SW_SHOW);
 361     }
 362
 363     SetModified(HasChanges());
 364 }
 365
 366 LRESULT CLayerUIPropPage::OnCtrlCommand(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL &bHandled)
 367 {
 368     UpdateControls();
 369     return 0;
 370 }
 371
 372 LRESULT CLayerUIPropPage::OnEditModes(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL &bHandled)
 373 {
 374     if (DialogBoxParam(g_hModule, MAKEINTRESOURCE(IDD_EDITCOMPATIBILITYMODES), m_hWnd, EditModesProc, (LPARAM)this) == IDOK)
 375         UpdateControls();
 376     return 0;
 377 }
 378
 379 LRESULT CLayerUIPropPage::OnClickNotify(INT uCode, LPNMHDR hdr, BOOL& bHandled)
 380 {
 381     if (hdr->idFrom == IDC_INFOLINK)
 382         ShellExecute(NULL, L"open", L"https://www.reactos.org/forum/viewforum.php?f=4", NULL, NULL, SW_SHOW);
 383     return 0;
 384 }
 385
 386 static void ListboxChanged(HWND hWnd)
 387 {
 388     int Sel = ListBox_GetCurSel(GetDlgItem(hWnd, IDC_COMPATIBILITYMODE));
 389     EnableWindow(GetDlgItem(hWnd, IDC_EDIT), Sel >= 0);
 390     EnableWindow(GetDlgItem(hWnd, IDC_DELETE), Sel >= 0);
 391 }
 392
 393 static void OnAdd(HWND hWnd)
 394 {
 395     HWND Combo = GetDlgItem(hWnd, IDC_NEWCOMPATIBILITYMODE);
 396
 397     int Length = ComboBox_GetTextLength(Combo);
 398     CComBSTR Str(Length);
 399     ComboBox_GetText(Combo, Str, Length+1);
 400     HWND List = GetDlgItem(hWnd, IDC_COMPATIBILITYMODE);
 401     int Index = ListBox_FindStringExact(List, -1, Str);
 402     if (Index == LB_ERR)
 403         Index = ListBox_AddString(List, Str);
 404     ListBox_SetCurSel(List, Index);
 405     ListboxChanged(hWnd);
 406     ComboBox_SetCurSel(Combo, -1);
 407     SetFocus(Combo);
 408 }
 409
 410 static BOOL ComboHasData(HWND hWnd)
 411 {
 412     HWND Combo = GetDlgItem(hWnd, IDC_NEWCOMPATIBILITYMODE);
 413     if (ComboBox_GetCurSel(Combo) >= 0)
 414         return TRUE;
 415     ULONG Len = ComboBox_GetTextLength(Combo);
 416     return Len > 0;
 417 }
 418
 419 INT_PTR CALLBACK CLayerUIPropPage::EditModesProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 420 {
 421     CLayerUIPropPage* page = NULL;
 422
 423     switch (uMsg)
 424     {
 425     case WM_INITDIALOG:
 426         page = (CLayerUIPropPage*)lParam;
 427         page->AddRef();
 428         ::SetProp(hWnd, ACP_WNDPROP, page);
 429         {
 430             HWND Combo = ::GetDlgItem(hWnd, IDC_NEWCOMPATIBILITYMODE);
 431             CComObject<CLayerStringList> pList;
 432
 433             while (TRUE)
 434             {
 435                 CComHeapPtr<OLECHAR> str;
 436                 HRESULT hr = pList.Next(1, &str, NULL);
 437                 if (hr != S_OK)
 438                     break;
 439                 ComboBox_AddString(Combo, str);
 440             }
 441
 442             HWND List = ::GetDlgItem(hWnd, IDC_COMPATIBILITYMODE);
 443             for (int n = 0; n < page->m_CustomLayers.GetSize(); ++n)
 444             {
 445                 const WCHAR* Str = page->m_CustomLayers[n].GetString();
 446                 int Index = ListBox_FindStringExact(List, -1, Str);
 447                 if (Index == LB_ERR)
 448                     Index = ListBox_AddString(List, Str);
 449             }
 450         }
 451         break;
 452     case WM_ENDSESSION:
 453     case WM_DESTROY:
 454         page = (CLayerUIPropPage*)::GetProp(hWnd, ACP_WNDPROP);
 455         ::RemoveProp(hWnd, ACP_WNDPROP);
 456         page->Release();
 457         break;
 458
 459     case WM_COMMAND:
 460         switch(LOWORD(wParam))
 461         {
 462         case IDC_ADD:
 463             OnAdd(hWnd);
 464             break;
 465         case IDC_EDIT:
 466         {
 467             HWND List = ::GetDlgItem(hWnd, IDC_COMPATIBILITYMODE);
 468             int Cur = ListBox_GetCurSel(List);
 469             int Length = ListBox_GetTextLen(List, Cur);
 470             CComBSTR Str(Length);
 471             ListBox_GetText(List, Cur, Str);
 472             ListBox_DeleteString(List, Cur);
 473             HWND Combo = ::GetDlgItem(hWnd, IDC_NEWCOMPATIBILITYMODE);
 474             ComboBox_SetCurSel(Combo, -1);
 475             ::SetWindowText(Combo,Str);
 476             ListboxChanged(hWnd);
 477             ComboBox_SetEditSel(Combo, 30000, 30000);
 478             ::SetFocus(Combo);
 479         }
 480             break;
 481         case IDC_DELETE:
 482         {
 483             HWND List = ::GetDlgItem(hWnd, IDC_COMPATIBILITYMODE);
 484             ListBox_DeleteString(List, ListBox_GetCurSel(List));
 485             ListboxChanged(hWnd);
 486         }
 487             break;
 488         case IDC_COMPATIBILITYMODE:
 489             ListboxChanged(hWnd);
 490             break;
 491         case IDC_NEWCOMPATIBILITYMODE:
 492         {
 493             ::EnableWindow(::GetDlgItem(hWnd, IDC_ADD), ComboHasData(hWnd));
 494         }
 495             break;
 496         case IDOK:
 497             /* Copy from list! */
 498         {
 499             if (ComboHasData(hWnd))
 500             {
 501                 CComBSTR question, title;
 502                 title.LoadString(g_hModule, IDS_TABTITLE);
 503                 question.LoadString(g_hModule, IDS_YOU_DID_NOT_ADD);
 504                 int result = ::MessageBoxW(hWnd, question, title, MB_YESNOCANCEL | MB_ICONQUESTION);
 505                 switch (result)
 506                 {
 507                 case IDYES:
 508                     OnAdd(hWnd);
 509                     break;
 510                 case IDNO:
 511                     break;
 512                 case IDCANCEL:
 513                     return FALSE;
 514                 }
 515             }
 516
 517             page = (CLayerUIPropPage*)::GetProp(hWnd, ACP_WNDPROP);
 518
 519             HWND List = ::GetDlgItem(hWnd, IDC_COMPATIBILITYMODE);
 520             int Count = ListBox_GetCount(List);
 521             page->m_CustomLayers.RemoveAll();
 522             for (int Cur = 0; Cur < Count; ++Cur)
 523             {
 524                 int Length = ListBox_GetTextLen(List, Cur);
 525                 CString Str;
 526                 LPWSTR Buffer = Str.GetBuffer(Length + 1);
 527                 ListBox_GetText(List, Cur, Buffer);
 528                 Str.ReleaseBuffer(Length);
 529                 page->m_CustomLayers.Add(Str);
 530             }
 531         }
 532         /* Fall trough */
 533         case IDCANCEL:
 534             ::EndDialog(hWnd, LOWORD(wParam));
 535             break;
 536         }
 537         break;
 538     case WM_CLOSE:
 539         ::EndDialog(hWnd, IDCANCEL);
 540         break;
 541     }
 542     return FALSE;
 543 }
 544
 545 static BOOL DisableShellext()
 546 {
 547     HKEY hkey;
 548     LSTATUS ret = RegOpenKeyExW(HKEY_LOCAL_MACHINE, L"SOFTWARE\\Policies\\Microsoft\\Windows\\AppCompat", 0, KEY_QUERY_VALUE, &hkey);
 549     BOOL Disable = FALSE;
 550     if (ret == ERROR_SUCCESS)
 551     {
 552         DWORD dwValue = 0;
 553         DWORD type, size = sizeof(dwValue);
 554         ret = RegQueryValueExW(hkey, L"DisableEngine", NULL, &type, (PBYTE)&dwValue, &size);
 555         if (ret == ERROR_SUCCESS && type == REG_DWORD)
 556         {
 557             Disable = !!dwValue;
 558         }
 559         if (!Disable)
 560         {
 561             size = sizeof(dwValue);
 562             ret = RegQueryValueExW(hkey, L"DisablePropPage", NULL, &type, (PBYTE)&dwValue, &size);
 563             if (ret == ERROR_SUCCESS && type == REG_DWORD)
 564             {
 565                 Disable = !!dwValue;
 566             }
 567         }
 568
 569         RegCloseKey(hkey);
 570     }
 571     return Disable;
 572 }
 573
 574 STDMETHODIMP CLayerUIPropPage::Initialize(LPCITEMIDLIST pidlFolder, LPDATAOBJECT pDataObj, HKEY hkeyProgID)
 575 {
 576     FORMATETC etc = { CF_HDROP, NULL, DVASPECT_CONTENT, -1, TYMED_HGLOBAL };
 577     STGMEDIUM stg;
 578
 579     if (DisableShellext())
 580         return E_ACCESSDENIED;
 581
 582     HRESULT hr = pDataObj->GetData(&etc, &stg);
 583     if (FAILED(hr))
 584     {
 585         ACDBG(L"Failed to retrieve Data from pDataObj.\r\n");
 586         return E_INVALIDARG;
 587     }
 588     hr = E_FAIL;
 589     HDROP hdrop = (HDROP)GlobalLock(stg.hGlobal);
 590     if (hdrop)
 591     {
 592         UINT uNumFiles = DragQueryFileW(hdrop, 0xFFFFFFFF, NULL, 0);
 593         if (uNumFiles == 1)
 594         {
 595             WCHAR szFile[MAX_PATH * 2];
 596             if (DragQueryFileW(hdrop, 0, szFile, _countof(szFile)))
 597             {
 598                 this->AddRef();
 599                 hr = InitFile(szFile);
 600             }
 601             else
 602             {
 603                 ACDBG(L"Failed to query the file.\r\n");
 604             }
 605         }
 606         else
 607         {
 608             ACDBG(L"Invalid number of files: %d\r\n", uNumFiles);
 609         }
 610         GlobalUnlock(stg.hGlobal);
 611     }
 612     else
 613     {
 614         ACDBG(L"Could not lock stg.hGlobal\r\n");
 615     }
 616     ReleaseStgMedium(&stg);
 617     return hr;
 618 }