modules/plugin/base/src/nsPluginDirServiceProvider.cpp
author Josh Aas <joshmoz@gmail.com>
Thu, 17 Feb 2011 03:45:20 -0500
changeset 62749 7f8e4c2ca53f2c51b26226f9153f52123e9120fa
parent 38323 eb700dca07558e3ff49223394a0854e5eb448ebe
child 62841 04527f9407f96d0a07074b56b260eeea9dde636c
permissions -rw-r--r--
Bug 633463: Never scan old XPCOM/OJI Java plugin directory. r=jmathies a=blocking2.0betaN+

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2001
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *  Conrad Carlen <ccarlen@netscape.com>
 *  Ere Maijala <emaijala@kolumbus.fi>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsPluginDirServiceProvider.h"

#include "nsCRT.h"
#include "nsILocalFile.h"
#include "nsIPrefBranch.h"
#include "nsIPrefService.h"
#include "nsDependentString.h"
#include "nsXPIDLString.h"
#include "prmem.h"
#include "nsArrayEnumerator.h"

typedef struct structVer
{
  WORD wMajor;
  WORD wMinor;
  WORD wRelease;
  WORD wBuild;
} verBlock;

static void
ClearVersion(verBlock *ver)
{
  ver->wMajor   = 0;
  ver->wMinor   = 0;
  ver->wRelease = 0;
  ver->wBuild   = 0;
}

static BOOL
FileExists(LPCWSTR szFile)
{
  return GetFileAttributesW(szFile) != 0xFFFFFFFF;
}

// Get file version information from a file
static BOOL
GetFileVersion(LPCWSTR szFile, verBlock *vbVersion)
{
  UINT              uLen;
  UINT              dwLen;
  BOOL              bRv;
  DWORD             dwHandle;
  LPVOID            lpData;
  LPVOID            lpBuffer;
  VS_FIXEDFILEINFO  *lpBuffer2;

  ClearVersion(vbVersion);
  if (FileExists(szFile)) {
    bRv    = TRUE;
#ifdef WINCE
    // WinCe takes a non const file path string, while desktop take a const
    LPWSTR lpFilepath = const_cast<LPWSTR>(szFile);
#else
    LPCWSTR lpFilepath = szFile;
#endif
    dwLen  = GetFileVersionInfoSizeW(lpFilepath, &dwHandle);
    lpData = (LPVOID)malloc(dwLen);
    uLen   = 0;

    if (lpData && GetFileVersionInfoW(lpFilepath, dwHandle, dwLen, lpData) != 0) {
      if (VerQueryValueW(lpData, L"\\", &lpBuffer, &uLen) != 0) {
        lpBuffer2 = (VS_FIXEDFILEINFO *)lpBuffer;

        vbVersion->wMajor   = HIWORD(lpBuffer2->dwFileVersionMS);
        vbVersion->wMinor   = LOWORD(lpBuffer2->dwFileVersionMS);
        vbVersion->wRelease = HIWORD(lpBuffer2->dwFileVersionLS);
        vbVersion->wBuild   = LOWORD(lpBuffer2->dwFileVersionLS);
      }
    }

    free(lpData);
  } else {
    /* File does not exist */
    bRv = FALSE;
  }

  return bRv;
}

// Will deep copy ver2 into ver1
static void
CopyVersion(verBlock *ver1, verBlock *ver2)
{
  ver1->wMajor   = ver2->wMajor;
  ver1->wMinor   = ver2->wMinor;
  ver1->wRelease = ver2->wRelease;
  ver1->wBuild   = ver2->wBuild;
}

// Convert a string version to a version struct
static void
TranslateVersionStr(const WCHAR* szVersion, verBlock *vbVersion)
{
  WCHAR* szNum1 = NULL;
  WCHAR* szNum2 = NULL;
  WCHAR* szNum3 = NULL;
  WCHAR* szNum4 = NULL;
  WCHAR* szJavaBuild = NULL;

  WCHAR *strVer = nsnull;
  if (szVersion) {
    strVer = wcsdup(szVersion);
  }

  if (!strVer) {
    // Out of memory
    ClearVersion(vbVersion);
    return;
  }

  // Java may be using an underscore instead of a dot for the build ID
  szJavaBuild = wcschr(strVer, '_');
  if (szJavaBuild) {
    szJavaBuild[0] = '.';
  }

  szNum1 = wcstok(strVer, L".");
  szNum2 = wcstok(NULL,   L".");
  szNum3 = wcstok(NULL,   L".");
  szNum4 = wcstok(NULL,   L".");

  vbVersion->wMajor   = szNum1 ? (WORD) _wtoi(szNum1) : 0;
  vbVersion->wMinor   = szNum2 ? (WORD) _wtoi(szNum2) : 0;
  vbVersion->wRelease = szNum3 ? (WORD) _wtoi(szNum3) : 0;
  vbVersion->wBuild   = szNum4 ? (WORD) _wtoi(szNum4) : 0;

  free(strVer);
}

// Compare two version struct, return zero if the same
static int
CompareVersion(verBlock vbVersionOld, verBlock vbVersionNew)
{
  if (vbVersionOld.wMajor > vbVersionNew.wMajor) {
    return 4;
  } else if (vbVersionOld.wMajor < vbVersionNew.wMajor) {
    return -4;
  }

  if (vbVersionOld.wMinor > vbVersionNew.wMinor) {
    return 3;
  } else if (vbVersionOld.wMinor < vbVersionNew.wMinor) {
    return -3;
  }

  if (vbVersionOld.wRelease > vbVersionNew.wRelease) {
    return 2;
  } else if (vbVersionOld.wRelease < vbVersionNew.wRelease) {
    return -2;
  }

  if (vbVersionOld.wBuild > vbVersionNew.wBuild) {
    return 1;
  } else if (vbVersionOld.wBuild < vbVersionNew.wBuild) {
    return -1;
  }

  /* the versions are all the same */
  return 0;
}

//*****************************************************************************
// nsPluginDirServiceProvider::Constructor/Destructor
//*****************************************************************************

nsPluginDirServiceProvider::nsPluginDirServiceProvider()
{
}

nsPluginDirServiceProvider::~nsPluginDirServiceProvider()
{
}

//*****************************************************************************
// nsPluginDirServiceProvider::nsISupports
//*****************************************************************************

NS_IMPL_THREADSAFE_ISUPPORTS1(nsPluginDirServiceProvider,
                              nsIDirectoryServiceProvider)

//*****************************************************************************
// nsPluginDirServiceProvider::nsIDirectoryServiceProvider
//*****************************************************************************

NS_IMETHODIMP
nsPluginDirServiceProvider::GetFile(const char *charProp, PRBool *persistant,
                                    nsIFile **_retval)
{
  nsCOMPtr<nsILocalFile>  localFile;
  nsresult rv = NS_ERROR_FAILURE;

  NS_ENSURE_ARG(charProp);

  *_retval = nsnull;
  *persistant = PR_FALSE;

  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
  if (!prefs)
    return NS_ERROR_FAILURE;

  if (nsCRT::strcmp(charProp, NS_WIN_4DOTX_SCAN_KEY) == 0) {
    // Check our prefs to see if scanning the 4.x folder has been
    // explictly overriden failure to get the pref is okay, we'll do
    // what we've been doing -- a filtered scan
    PRBool bScan4x;
    if (NS_SUCCEEDED(prefs->GetBoolPref(NS_WIN_4DOTX_SCAN_KEY, &bScan4x)) &&
        !bScan4x) {
      return NS_ERROR_FAILURE;
    }

    // Look for the plugin folder that the user has in their
    // Communicator 4x install
    HKEY keyloc;
    long result;
    DWORD type;
    WCHAR szKey[_MAX_PATH] = L"Software\\Netscape\\Netscape Navigator";
    WCHAR path[_MAX_PATH];

    result = ::RegOpenKeyExW(HKEY_LOCAL_MACHINE, szKey, 0, KEY_READ, &keyloc);

    if (result == ERROR_SUCCESS) {
      WCHAR current_version[80];
      DWORD length = NS_ARRAY_LENGTH(current_version);

      result = ::RegQueryValueExW(keyloc, L"CurrentVersion", NULL, &type,
                                  (LPBYTE)&current_version, &length);

      ::RegCloseKey(keyloc);
      wcscat(szKey, L"\\");
      wcscat(szKey, current_version);
      wcscat(szKey, L"\\Main");
      result = ::RegOpenKeyExW(HKEY_LOCAL_MACHINE, szKey, 0, KEY_READ, &keyloc);

      if (result == ERROR_SUCCESS) {
        DWORD pathlen = NS_ARRAY_LENGTH(path);

        result = ::RegQueryValueExW(keyloc, L"Plugins Directory", NULL, &type,
                                   (LPBYTE)&path, &pathlen);
        if (result == ERROR_SUCCESS) {
          rv = NS_NewLocalFile(nsDependentString(path),
                               PR_TRUE, getter_AddRefs(localFile));
        }

        ::RegCloseKey(keyloc);
      }
    }
  } else if (nsCRT::strcmp(charProp, NS_WIN_JRE_SCAN_KEY) == 0) {
    nsXPIDLCString strVer;
    if (NS_FAILED(prefs->GetCharPref(charProp, getter_Copies(strVer))))
      return NS_ERROR_FAILURE;
    verBlock minVer;
    TranslateVersionStr(NS_ConvertASCIItoUTF16(strVer).get(), &minVer);

    // Look for the Java OJI plugin via the JRE install path
    HKEY baseloc;
    HKEY keyloc;
    HKEY entryloc;
    FILETIME modTime;
    DWORD type;
    DWORD index = 0;
    DWORD numChars = _MAX_PATH;
    DWORD pathlen;
    verBlock maxVer;
    ClearVersion(&maxVer);
    WCHAR curKey[_MAX_PATH] = L"Software\\JavaSoft\\Java Runtime Environment";
    WCHAR path[_MAX_PATH];
    // Add + 15 to prevent buffer overrun when adding \bin (+ optionally
    // \new_plugin)
#define JAVA_PATH_SIZE _MAX_PATH + 15
    WCHAR newestPath[JAVA_PATH_SIZE];
    WCHAR browserJavaVersion[_MAX_PATH];

    newestPath[0] = 0;
    LONG result = ::RegOpenKeyExW(HKEY_LOCAL_MACHINE, curKey, 0, KEY_READ,
                                  &baseloc);
    if (ERROR_SUCCESS != result)
      return NS_ERROR_FAILURE;

    // Look for "BrowserJavaVersion"
    if (ERROR_SUCCESS != ::RegQueryValueExW(baseloc, L"BrowserJavaVersion", NULL,
                                            NULL, (LPBYTE)&browserJavaVersion,
                                            &numChars))
      browserJavaVersion[0] = 0;

    // We must enumerate through the keys because what if there is
    // more than one version?
    do {
      path[0] = 0;
      numChars = _MAX_PATH;
      pathlen = NS_ARRAY_LENGTH(path);
      result = ::RegEnumKeyExW(baseloc, index, curKey, &numChars, NULL, NULL,
                               NULL, &modTime);
      index++;

      // Skip major.minor as it always points to latest in its family
      numChars = 0;
      for (WCHAR *p = curKey; *p; p++) {
        if (*p == '.') {
          numChars++;
        }
      }
      if (numChars < 2)
        continue;

      if (ERROR_SUCCESS == result) {
        if (ERROR_SUCCESS == ::RegOpenKeyExW(baseloc, curKey, 0,
                                             KEY_QUERY_VALUE, &keyloc)) {
          // We have a sub key
          if (ERROR_SUCCESS == ::RegQueryValueExW(keyloc, L"JavaHome", NULL,
                                                  &type, (LPBYTE)&path,
                                                  &pathlen)) {
            verBlock curVer;
            TranslateVersionStr(curKey, &curVer);
            if (CompareVersion(curVer, minVer) >= 0) {
              if (!wcsncmp(browserJavaVersion, curKey, _MAX_PATH)) {
                wcscpy(newestPath, path);
                ::RegCloseKey(keyloc);
                break;
              }

              if (CompareVersion(curVer, maxVer) >= 0) {
                wcscpy(newestPath, path);
                CopyVersion(&maxVer, &curVer);
              }
            }
          }
          ::RegCloseKey(keyloc);
        }
      }
    } while (ERROR_SUCCESS == result);

    ::RegCloseKey(baseloc);

    if (newestPath[0] == 0) {
      return NS_ERROR_FAILURE;
    }

    // We require the newer NPAPI Java plugin.
    wcscat(newestPath, L"\\bin\\new_plugin");

    rv = NS_NewLocalFile(nsDependentString(newestPath),
                         PR_TRUE, getter_AddRefs(localFile));

    if (NS_SUCCEEDED(rv)) {
      const WCHAR mozPath[_MAX_PATH] = L"Software\\mozilla.org\\Mozilla";
      if (ERROR_SUCCESS == ::RegCreateKeyExW(HKEY_LOCAL_MACHINE, mozPath, 0,
                                             NULL, REG_OPTION_NON_VOLATILE,
                                             KEY_SET_VALUE|KEY_QUERY_VALUE,
                                             NULL, &entryloc, NULL)) {
        if (ERROR_SUCCESS != ::RegQueryValueExW(entryloc, L"CurrentVersion", 0,
                                                NULL, NULL, NULL)) {
          static const WCHAR kMozillaVersion[] = NS_L(MOZILLA_VERSION);
          ::RegSetValueExW(entryloc, L"CurrentVersion", 0, REG_SZ,
                           (const BYTE*) kMozillaVersion,
                           NS_ARRAY_LENGTH(kMozillaVersion));
        }
        ::RegCloseKey(entryloc);
      }
    }
  } else if (nsCRT::strcmp(charProp, NS_WIN_QUICKTIME_SCAN_KEY) == 0) {
    nsXPIDLCString strVer;
    if (NS_FAILED(prefs->GetCharPref(charProp, getter_Copies(strVer))))
      return NS_ERROR_FAILURE;
    verBlock minVer;
    TranslateVersionStr(NS_ConvertASCIItoUTF16(strVer).get(), &minVer);

    // Look for the Quicktime system installation plugins directory
    HKEY keyloc;
    long result;
    DWORD type;
    verBlock qtVer;
    ClearVersion(&qtVer);
    WCHAR path[_MAX_PATH];
    DWORD pathlen = NS_ARRAY_LENGTH(path);

    // First we need to check the version of Quicktime via checking
    // the EXE's version table
    if (ERROR_SUCCESS == ::RegOpenKeyExW(HKEY_LOCAL_MACHINE,
                                         L"software\\Microsoft\\Windows\\CurrentVersion\\App Paths\\QuickTimePlayer.exe",
                                         0, KEY_READ, &keyloc)) {
      if (ERROR_SUCCESS == ::RegQueryValueExW(keyloc, NULL, NULL, &type,
                                              (LPBYTE)&path, &pathlen)) {
        GetFileVersion(path, &qtVer);
      }
      ::RegCloseKey(keyloc);
    }
    if (CompareVersion(qtVer, minVer) < 0)
      return rv;

    if (ERROR_SUCCESS == ::RegOpenKeyExW(HKEY_LOCAL_MACHINE,
                                         L"software\\Apple Computer, Inc.\\QuickTime",
                                        0, KEY_READ, &keyloc)) {
      DWORD pathlen = NS_ARRAY_LENGTH(path);

      result = ::RegQueryValueExW(keyloc, L"InstallDir", NULL, &type,
                                  (LPBYTE)&path, &pathlen);
      wcscat(path, L"\\Plugins");
      if (result == ERROR_SUCCESS)
        rv = NS_NewLocalFile(nsDependentString(path), PR_TRUE,
                             getter_AddRefs(localFile));
      ::RegCloseKey(keyloc);
    }
  } else if (nsCRT::strcmp(charProp, NS_WIN_WMP_SCAN_KEY) == 0) {
    nsXPIDLCString strVer;
    if (NS_FAILED(prefs->GetCharPref(charProp, getter_Copies(strVer))))
      return NS_ERROR_FAILURE;
    verBlock minVer;
    TranslateVersionStr(NS_ConvertASCIItoUTF16(strVer).get(), &minVer);

    // Look for Windows Media Player system installation plugins directory
    HKEY keyloc;
    DWORD type;
    verBlock wmpVer;
    ClearVersion(&wmpVer);
    WCHAR path[_MAX_PATH];
    DWORD pathlen = NS_ARRAY_LENGTH(path);

    // First we need to check the version of WMP
    if (ERROR_SUCCESS == ::RegOpenKeyExW(HKEY_LOCAL_MACHINE,
                                         L"software\\Microsoft\\Windows\\CurrentVersion\\App Paths\\wmplayer.exe",
                                         0, KEY_READ, &keyloc)) {
      if (ERROR_SUCCESS == ::RegQueryValueExW(keyloc, NULL, NULL, &type,
                                              (LPBYTE)&path, &pathlen)) {
        GetFileVersion(path, &wmpVer);
      }
      ::RegCloseKey(keyloc);
    }
    if (CompareVersion(wmpVer, minVer) < 0)
      return rv;

    if (ERROR_SUCCESS == ::RegOpenKeyExW(HKEY_LOCAL_MACHINE,
                                         L"software\\Microsoft\\MediaPlayer", 0,
                                         KEY_READ, &keyloc)) {
      if (ERROR_SUCCESS == ::RegQueryValueExW(keyloc, L"Installation Directory",
                                             NULL, &type, (LPBYTE)&path,
                                             &pathlen)) {
        rv = NS_NewLocalFile(nsDependentString(path), PR_TRUE,
                             getter_AddRefs(localFile));
      }

      ::RegCloseKey(keyloc);
    }
  } else if (nsCRT::strcmp(charProp, NS_WIN_ACROBAT_SCAN_KEY) == 0) {
    nsXPIDLCString strVer;
    if (NS_FAILED(prefs->GetCharPref(charProp, getter_Copies(strVer)))) {
      return NS_ERROR_FAILURE;
    }

    verBlock minVer;
    TranslateVersionStr(NS_ConvertASCIItoUTF16(strVer).get(), &minVer);

    // Look for Adobe Acrobat system installation plugins directory
    HKEY baseloc;
    HKEY keyloc;
    FILETIME modTime;
    DWORD type;
    DWORD index = 0;
    DWORD numChars = _MAX_PATH;
    DWORD pathlen;
    verBlock maxVer;
    ClearVersion(&maxVer);
    WCHAR curKey[_MAX_PATH] = L"software\\Adobe\\Acrobat Reader";
    WCHAR path[_MAX_PATH];
    // Add + 8 to prevent buffer overrun when adding \browser
    WCHAR newestPath[_MAX_PATH + 8];

    newestPath[0] = 0;
    if (ERROR_SUCCESS != ::RegOpenKeyExW(HKEY_LOCAL_MACHINE, curKey, 0,
                                         KEY_READ, &baseloc)) {
      wcscpy(curKey, L"software\\Adobe\\Adobe Acrobat");
      if (ERROR_SUCCESS != ::RegOpenKeyExW(HKEY_LOCAL_MACHINE, curKey, 0,
                                           KEY_READ, &baseloc)) {
        return NS_ERROR_FAILURE;
      }
    }

    // We must enumerate through the keys because what if there is
    // more than one version?
    LONG result = ERROR_SUCCESS;
    while (ERROR_SUCCESS == result) {
      path[0] = 0;
      numChars = _MAX_PATH;
      pathlen = NS_ARRAY_LENGTH(path);
      result = ::RegEnumKeyExW(baseloc, index, curKey, &numChars, NULL, NULL,
                               NULL, &modTime);
      index++;

      if (ERROR_SUCCESS == result) {
        verBlock curVer;
        TranslateVersionStr(curKey, &curVer);
        wcscat(curKey, L"\\InstallPath");
        if (ERROR_SUCCESS == ::RegOpenKeyExW(baseloc, curKey, 0,
                                             KEY_QUERY_VALUE, &keyloc)) {
          // We have a sub key
          if (ERROR_SUCCESS == ::RegQueryValueExW(keyloc, NULL, NULL, &type,
                                                  (LPBYTE)&path, &pathlen)) {
            if (CompareVersion(curVer, maxVer) >= 0 &&
                CompareVersion(curVer, minVer) >= 0) {
              wcscpy(newestPath, path);
              CopyVersion(&maxVer, &curVer);
            }
          }

          ::RegCloseKey(keyloc);
        }
      }
    }

    ::RegCloseKey(baseloc);

    if (newestPath[0] != 0) {
      wcscat(newestPath, L"\\browser");
      rv = NS_NewLocalFile(nsDependentString(newestPath), PR_TRUE,
                           getter_AddRefs(localFile));
    }

  }

  if (localFile && NS_SUCCEEDED(rv))
    return CallQueryInterface(localFile, _retval);

  return rv;
}

nsresult
nsPluginDirServiceProvider::GetPLIDDirectories(nsISimpleEnumerator **aEnumerator)
{
  NS_ENSURE_ARG_POINTER(aEnumerator);
  *aEnumerator = nsnull;

  nsCOMArray<nsILocalFile> dirs;

  GetPLIDDirectoriesWithHKEY(HKEY_CURRENT_USER, dirs);
  GetPLIDDirectoriesWithHKEY(HKEY_LOCAL_MACHINE, dirs);

  return NS_NewArrayEnumerator(aEnumerator, dirs);
}

nsresult
nsPluginDirServiceProvider::GetPLIDDirectoriesWithHKEY(HKEY aKey, nsCOMArray<nsILocalFile> &aDirs)
{
  WCHAR subkey[_MAX_PATH] = L"Software\\MozillaPlugins";
  HKEY baseloc;

  if (ERROR_SUCCESS != ::RegOpenKeyExW(aKey, subkey, 0, KEY_READ, &baseloc))
    return NS_ERROR_FAILURE;

  DWORD index = 0;
  DWORD subkeylen = _MAX_PATH;
  FILETIME modTime;
  while (ERROR_SUCCESS == ::RegEnumKeyExW(baseloc, index++, subkey, &subkeylen,
                                          NULL, NULL, NULL, &modTime)) {
    subkeylen = _MAX_PATH;
    HKEY keyloc;

    if (ERROR_SUCCESS == ::RegOpenKeyExW(baseloc, subkey, 0, KEY_QUERY_VALUE,
                                         &keyloc)) {
      DWORD type;
      WCHAR path[_MAX_PATH];
      DWORD pathlen = NS_ARRAY_LENGTH(path);

      if (ERROR_SUCCESS == ::RegQueryValueExW(keyloc, L"Path", NULL, &type,
                                              (LPBYTE)&path, &pathlen)) {
        nsCOMPtr<nsILocalFile> localFile;
        if (NS_SUCCEEDED(NS_NewLocalFile(nsDependentString(path), PR_TRUE,
                                         getter_AddRefs(localFile))) &&
            localFile)
        {
          // Some vendors use a path directly to the DLL so chop off
          // the filename
          PRBool isDir = PR_FALSE;
          if (NS_SUCCEEDED(localFile->IsDirectory(&isDir)) && !isDir) {
            nsCOMPtr<nsIFile> temp;
            localFile->GetParent(getter_AddRefs(temp));
            if (temp)
              localFile = do_QueryInterface(temp);
          }

          // Now we check to make sure it's actually on disk and
          // To see if we already have this directory in the array
          PRBool isFileThere = PR_FALSE;
          PRBool isDupEntry = PR_FALSE;
          if (NS_SUCCEEDED(localFile->Exists(&isFileThere)) && isFileThere) {
            PRInt32 c = aDirs.Count();
            for (PRInt32 i = 0; i < c; i++) {
              nsIFile *dup = static_cast<nsIFile*>(aDirs[i]);
              if (dup &&
                  NS_SUCCEEDED(dup->Equals(localFile, &isDupEntry)) &&
                  isDupEntry) {
                break;
              }
            }

            if (!isDupEntry) {
              aDirs.AppendObject(localFile);
            }
          }
        }
      }
      ::RegCloseKey(keyloc);
    }
  }
  ::RegCloseKey(baseloc);
  return NS_OK;
}