palemoon27/browser/components/shell/nsWindowsShellService.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsWindowsShellService.h"

#include "imgIContainer.h"
#include "imgIRequest.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/RefPtr.h"
#include "nsIDOMElement.h"
#include "nsIDOMHTMLImageElement.h"
#include "nsIImageLoadingContent.h"
#include "nsIPrefService.h"
#include "nsIPrefLocalizedString.h"
#include "nsIServiceManager.h"
#include "nsIStringBundle.h"
#include "nsNetUtil.h"
#include "nsServiceManagerUtils.h"
#include "nsShellService.h"
#include "nsIProcess.h"
#include "nsICategoryManager.h"
#include "nsBrowserCompsCID.h"
#include "nsDirectoryServiceUtils.h"
#include "nsAppDirectoryServiceDefs.h"
#include "nsDirectoryServiceDefs.h"
#include "nsIWindowsRegKey.h"
#include "nsUnicharUtils.h"
#include "nsIWinTaskbar.h"
#include "nsISupportsPrimitives.h"
#include "nsIURLFormatter.h"
#include "nsThreadUtils.h"
#include "nsXULAppAPI.h"
#include "mozilla/WindowsVersion.h"

#include "windows.h"
#include "shellapi.h"

#ifdef _WIN32_WINNT
#undef _WIN32_WINNT
#endif
#define _WIN32_WINNT 0x0600
#define INITGUID
#undef NTDDI_VERSION
#define NTDDI_VERSION NTDDI_WIN8
// Needed for access to IApplicationActivationManager
#include <shlobj.h>

#include <mbstring.h>
#include <shlwapi.h>

#include <lm.h>
#undef ACCESS_READ

#ifndef MAX_BUF
#define MAX_BUF 4096
#endif

#define REG_SUCCEEDED(val) \
  (val == ERROR_SUCCESS)

#define REG_FAILED(val) \
  (val != ERROR_SUCCESS)

#define NS_TASKBAR_CONTRACTID "@mozilla.org/windows-taskbar;1"

using mozilla::IsWin8OrLater;
using namespace mozilla;
using namespace mozilla::gfx;

NS_IMPL_ISUPPORTS(nsWindowsShellService, nsIWindowsShellService, nsIShellService)

static nsresult
OpenKeyForReading(HKEY aKeyRoot, const nsAString& aKeyName, HKEY* aKey)
{
  const nsString &flatName = PromiseFlatString(aKeyName);

  DWORD res = ::RegOpenKeyExW(aKeyRoot, flatName.get(), 0, KEY_READ, aKey);
  switch (res) {
  case ERROR_SUCCESS:
    break;
  case ERROR_ACCESS_DENIED:
    return NS_ERROR_FILE_ACCESS_DENIED;
  case ERROR_FILE_NOT_FOUND:
    return NS_ERROR_NOT_AVAILABLE;
  }

  return NS_OK;
}

static bool
GetPrefString(const nsCString& aPrefName, nsAString& aValue)
{
  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
  if (!prefs) {
    return false;
  }

  nsAutoCString prefCStr;
  nsresult rv = prefs->GetCharPref(aPrefName.get(),
                                   getter_Copies(prefCStr));
  if (NS_FAILED(rv)) {
    return false;
  }
  CopyUTF8toUTF16(prefCStr, aValue);

  return true;
}

static bool
SetPrefString(const nsCString& aPrefName, const nsString& aValue)
{
  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
  if (!prefs) {
    return false;
  }

  nsresult rv = prefs->SetCharPref(aPrefName.get(),
                                   NS_ConvertUTF16toUTF8(aValue).get());
  return NS_SUCCEEDED(rv);
}

///////////////////////////////////////////////////////////////////////////////
// Default Browser Registry Settings
//
// The setting of these values are made by an external binary since writing
// these values may require elevation.
//
// - File Extension Mappings
//   -----------------------
//   The following file extensions:
//    .htm .html .shtml .xht .xhtml 
//   are mapped like so:
//
//   HKCU\SOFTWARE\Classes\.<ext>\      (default)         REG_SZ     PaleMoonHTML
//
//   as aliases to the class:
//
//   HKCU\SOFTWARE\Classes\PaleMoonHTML\
//     DefaultIcon                      (default)         REG_SZ     <apppath>,1
//     shell\open\command               (default)         REG_SZ     <apppath> -osint -url "%1"
//     shell\open\ddeexec               (default)         REG_SZ     <empty string>
//
// - Windows Vista and above Protocol Handler
//
//   HKCU\SOFTWARE\Classes\PaleMoonURL\  (default)         REG_SZ     <appname> URL
//                                      EditFlags         REG_DWORD  2
//                                      FriendlyTypeName  REG_SZ     <appname> URL
//     DefaultIcon                      (default)         REG_SZ     <apppath>,1
//     shell\open\command               (default)         REG_SZ     <apppath> -osint -url "%1"
//     shell\open\ddeexec               (default)         REG_SZ     <empty string>
//
// - Protocol Mappings
//   -----------------
//   The following protocols:
//    HTTP, HTTPS, FTP
//   are mapped like so:
//
//   HKCU\SOFTWARE\Classes\<protocol>\
//     DefaultIcon                      (default)         REG_SZ     <apppath>,1
//     shell\open\command               (default)         REG_SZ     <apppath> -osint -url "%1"
//     shell\open\ddeexec               (default)         REG_SZ     <empty string>
//
// - Windows Start Menu (XP SP1 and newer)
//   -------------------------------------------------
//   The following keys are set to make PaleMoon appear in the Start Menu as the
//   browser:
//   
//   HKCU\SOFTWARE\Clients\StartMenuInternet\FIREFOX.EXE\
//                                      (default)         REG_SZ     <appname>
//     DefaultIcon                      (default)         REG_SZ     <apppath>,0
//     InstallInfo                      HideIconsCommand  REG_SZ     <uninstpath> /HideShortcuts
//     InstallInfo                      IconsVisible      REG_DWORD  1
//     InstallInfo                      ReinstallCommand  REG_SZ     <uninstpath> /SetAsDefaultAppGlobal
//     InstallInfo                      ShowIconsCommand  REG_SZ     <uninstpath> /ShowShortcuts
//     shell\open\command               (default)         REG_SZ     <apppath>
//     shell\properties                 (default)         REG_SZ     <appname> &Options
//     shell\properties\command         (default)         REG_SZ     <apppath> -preferences
//     shell\safemode                   (default)         REG_SZ     <appname> &Safe Mode
//     shell\safemode\command           (default)         REG_SZ     <apppath> -safe-mode
//

// The values checked are all default values so the value name is not needed.
typedef struct {
  const char* keyName;
  const char* valueData;
  const char* oldValueData;
} SETTING;

#define APP_REG_NAME L"Pale Moon"
#define VAL_FILE_ICON "%APPPATH%,1"
#define VAL_OPEN "\"%APPPATH%\" -osint -url \"%1\""
#define OLD_VAL_OPEN "\"%APPPATH%\" -requestPending -osint -url \"%1\""
#define DI "\\DefaultIcon"
#define SOC "\\shell\\open\\command"
#define SOD "\\shell\\open\\ddeexec"
// Used for updating the FTP protocol handler's shell open command under HKCU.
#define FTP_SOC L"Software\\Classes\\ftp\\shell\\open\\command"

#define MAKE_KEY_NAME1(PREFIX, MID) \
  PREFIX MID

// The DefaultIcon registry key value should never be used when checking if
// PaleMoon is the default browser for file handlers since other applications
// (e.g. MS Office) may modify the DefaultIcon registry key value to add Icon
// Handlers. see http://msdn2.microsoft.com/en-us/library/aa969357.aspx for
// more info. The FTP protocol is not checked so advanced users can set the FTP
// handler to another application and still have PaleMoon check if it is the
// default HTTP and HTTPS handler.
// *** Do not add additional checks here unless you skip them when aForAllTypes
// is false below***.
static SETTING gSettings[] = {
  // File Handler Class
  // ***keep this as the first entry because when aForAllTypes is not set below
  // it will skip over this check.***
  { MAKE_KEY_NAME1("PaleMoonHTML", SOC), VAL_OPEN, OLD_VAL_OPEN },

  // Protocol Handler Class - for Vista and above
  { MAKE_KEY_NAME1("PaleMoonURL", SOC), VAL_OPEN, OLD_VAL_OPEN },

  // Protocol Handlers
  { MAKE_KEY_NAME1("HTTP", DI), VAL_FILE_ICON },
  { MAKE_KEY_NAME1("HTTP", SOC), VAL_OPEN, OLD_VAL_OPEN },
  { MAKE_KEY_NAME1("HTTPS", DI), VAL_FILE_ICON },
  { MAKE_KEY_NAME1("HTTPS", SOC), VAL_OPEN, OLD_VAL_OPEN }
};

// The settings to disable DDE are separate from the default browser settings
// since they are only checked when PaleMoon is the default browser and if they
// are incorrect they are fixed without notifying the user.
static SETTING gDDESettings[] = {
  // File Handler Class
  { MAKE_KEY_NAME1("Software\\Classes\\PaleMoonHTML", SOD) },

  // Protocol Handler Class - for Vista and above
  { MAKE_KEY_NAME1("Software\\Classes\\PaleMoonURL", SOD) },

  // Protocol Handlers
  { MAKE_KEY_NAME1("Software\\Classes\\FTP", SOD) },
  { MAKE_KEY_NAME1("Software\\Classes\\HTTP", SOD) },
  { MAKE_KEY_NAME1("Software\\Classes\\HTTPS", SOD) }
};

nsresult
GetHelperPath(nsAutoString& aPath)
{
  nsresult rv;
  nsCOMPtr<nsIProperties> directoryService = 
    do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIFile> appHelper;
  rv = directoryService->Get(XRE_EXECUTABLE_FILE,
                             NS_GET_IID(nsIFile),
                             getter_AddRefs(appHelper));
  NS_ENSURE_SUCCESS(rv, rv);

  rv = appHelper->SetNativeLeafName(NS_LITERAL_CSTRING("uninstall"));
  NS_ENSURE_SUCCESS(rv, rv);

  rv = appHelper->AppendNative(NS_LITERAL_CSTRING("helper.exe"));
  NS_ENSURE_SUCCESS(rv, rv);

  rv = appHelper->GetPath(aPath);

  aPath.Insert(L'"', 0);
  aPath.Append(L'"');
  return rv;
}

nsresult
LaunchHelper(nsAutoString& aPath)
{
  STARTUPINFOW si = {sizeof(si), 0};
  PROCESS_INFORMATION pi = {0};

  if (!CreateProcessW(nullptr, (LPWSTR)aPath.get(), nullptr, nullptr, FALSE,
                      0, nullptr, nullptr, &si, &pi)) {
    return NS_ERROR_FAILURE;
  }

  CloseHandle(pi.hProcess);
  CloseHandle(pi.hThread);
  return NS_OK;
}

NS_IMETHODIMP
nsWindowsShellService::ShortcutMaintenance()
{
  nsresult rv;

  // XXX App ids were updated to a constant install path hash,
  // XXX this code can be removed after a few upgrade cycles.

  // Launch helper.exe so it can update the application user model ids on
  // shortcuts in the user's taskbar and start menu. This keeps older pinned
  // shortcuts grouped correctly after major updates. Note, we also do this
  // through the upgrade installer script, however, this is the only place we
  // have a chance to trap links created by users who do control the install/
  // update process of the browser.

  nsCOMPtr<nsIWinTaskbar> taskbarInfo =
    do_GetService(NS_TASKBAR_CONTRACTID);
  if (!taskbarInfo) // If we haven't built with win7 sdk features, this fails.
    return NS_OK;

  // Avoid if this isn't Win7+
  bool isSupported = false;
  taskbarInfo->GetAvailable(&isSupported);
  if (!isSupported)
    return NS_OK;

  nsAutoString appId;
  if (NS_FAILED(taskbarInfo->GetDefaultGroupId(appId)))
    return NS_ERROR_UNEXPECTED;

  NS_NAMED_LITERAL_CSTRING(prefName, "browser.taskbar.lastgroupid");
  nsCOMPtr<nsIPrefBranch> prefs =
    do_GetService(NS_PREFSERVICE_CONTRACTID);
  if (!prefs)
    return NS_ERROR_UNEXPECTED;

  nsCOMPtr<nsISupportsString> prefString;
  rv = prefs->GetComplexValue(prefName.get(),
                              NS_GET_IID(nsISupportsString),
                              getter_AddRefs(prefString));
  if (NS_SUCCEEDED(rv)) {
    nsAutoString version;
    prefString->GetData(version);
    if (!version.IsEmpty() && version.Equals(appId)) {
      // We're all good, get out of here.
      return NS_OK;
    }
  }
  // Update the version in prefs
  prefString =
    do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID, &rv);
  if (NS_FAILED(rv))
    return rv;

  prefString->SetData(appId);
  rv = prefs->SetComplexValue(prefName.get(),
                              NS_GET_IID(nsISupportsString),
                              prefString);
  if (NS_FAILED(rv)) {
    NS_WARNING("Couldn't set last user model id!");
    return NS_ERROR_UNEXPECTED;
  }

  nsAutoString appHelperPath;
  if (NS_FAILED(GetHelperPath(appHelperPath)))
    return NS_ERROR_UNEXPECTED;

  appHelperPath.AppendLiteral(" /UpdateShortcutAppUserModelIds");

  return LaunchHelper(appHelperPath);
}

static bool
IsAARDefault(const RefPtr<IApplicationAssociationRegistration>& pAAR,
             LPCWSTR aClassName)
{
  // Make sure the Prog ID matches what we have
  LPWSTR registeredApp;
  bool isProtocol = *aClassName != L'.';
  ASSOCIATIONTYPE queryType = isProtocol ? AT_URLPROTOCOL : AT_FILEEXTENSION;
  HRESULT hr = pAAR->QueryCurrentDefault(aClassName, queryType, AL_EFFECTIVE,
                                         &registeredApp);
  if (FAILED(hr)) {
    return false;
  }

  LPCWSTR progID = isProtocol ? L"ArcticFoxURL" : L"ArcticFoxHTML";
  bool isDefault = !wcsicmp(registeredApp, progID);
  CoTaskMemFree(registeredApp);

  return isDefault;
}

static void
GetUserChoiceKeyName(LPCWSTR aClassName, bool aIsProtocol,
                     nsAString& aKeyName)
{
  aKeyName.AssignLiteral(aIsProtocol
    ? "Software\\Microsoft\\Windows\\Shell\\Associations\\UrlAssociations\\"
    : "Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\FileExts\\");
  aKeyName.Append(aClassName);
  aKeyName.AppendLiteral("\\UserChoice");
}

static void
GetHashPrefName(LPCWSTR aClassName, nsACString& aPrefName)
{
  aPrefName.AssignLiteral("browser.shell.associationHash.");
  aPrefName.Append(NS_ConvertUTF16toUTF8(*aClassName == L'.' ? aClassName + 1
                                                             : aClassName));
}

static bool
SaveWin8RegistryHash(const RefPtr<IApplicationAssociationRegistration>& pAAR,
                     LPCWSTR aClassName)
{
  bool isProtocol = *aClassName != L'.';
  bool isDefault = IsAARDefault(pAAR, aClassName);
  // We can save the value only if ArctiFox is the default.
  if (!isDefault) {
    return isDefault;
  }

  nsAutoString keyName;
  GetUserChoiceKeyName(aClassName, isProtocol, keyName);

  nsCOMPtr<nsIWindowsRegKey> regKey =
    do_CreateInstance("@mozilla.org/windows-registry-key;1");
  if (!regKey) {
    return isDefault;
  }

  nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
                             keyName, nsIWindowsRegKey::ACCESS_READ);
  if (NS_FAILED(rv)) {
    return isDefault;
  }

  nsAutoString hash;
  rv = regKey->ReadStringValue(NS_LITERAL_STRING("Hash"), hash);
  if (NS_FAILED(rv)) {
    return isDefault;
  }

  nsAutoCString prefName;
  GetHashPrefName(aClassName, prefName);
  SetPrefString(prefName, hash);

  return isDefault;
}

static bool
RestoreWin8RegistryHash(const RefPtr<IApplicationAssociationRegistration>& pAAR,
                        LPCWSTR aClassName)
{
  nsAutoCString prefName;
  GetHashPrefName(aClassName, prefName);
  nsAutoString hash;
  if (!GetPrefString(prefName, hash)) {
    return false;
  }

  bool isProtocol = *aClassName != L'.';
  nsString progId = isProtocol ? NS_LITERAL_STRING("ArcticFoxURL")
                               : NS_LITERAL_STRING("ArcticFoxHTML");

  nsAutoString keyName;
  GetUserChoiceKeyName(aClassName, isProtocol, keyName);

  nsCOMPtr<nsIWindowsRegKey> regKey =
    do_CreateInstance("@mozilla.org/windows-registry-key;1");
  if (!regKey) {
    return false;
  }

  nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
                             keyName, nsIWindowsRegKey::ACCESS_READ);
  if (NS_SUCCEEDED(rv)) {
    nsAutoString currValue;
    if (NS_SUCCEEDED(regKey->ReadStringValue(NS_LITERAL_STRING("Hash"),
                                             currValue)) &&
        currValue.Equals(hash) &&
        NS_SUCCEEDED(regKey->ReadStringValue(NS_LITERAL_STRING("ProgId"),
                                             currValue)) &&
        currValue.Equals(progId)) {
      // The value is already set.
      return true;
    }
    // We need to close this explicitly because nsIWindowsRegKey::SetKey
    // does not close the old key.
    regKey->Close();
  }

  // We have to use the registry function directly because
  // nsIWindowsRegKey::Create will only return NS_ERROR_FAILURE
  // on failure.
  HKEY theKey;
  DWORD res = ::RegOpenKeyExW(HKEY_CURRENT_USER, keyName.get(), 0,
                              KEY_READ | KEY_SET_VALUE, &theKey);
  if (REG_FAILED(res)) {
    if (res != ERROR_ACCESS_DENIED && res != ERROR_FILE_NOT_FOUND) {
      return false;
    }
    if (res == ERROR_ACCESS_DENIED) {
      res = ::RegDeleteKeyW(HKEY_CURRENT_USER, keyName.get());
      if (REG_FAILED(res)) {
        return false;
      }
    }
    res = ::RegCreateKeyExW(HKEY_CURRENT_USER, keyName.get(), 0,
                            nullptr, 0, KEY_READ | KEY_SET_VALUE,
                            nullptr, &theKey, nullptr);
    if (REG_FAILED(res)) {
      return false;
    }
  }
  regKey->SetKey(theKey);

  rv = regKey->WriteStringValue(NS_LITERAL_STRING("Hash"), hash);
  if (NS_FAILED(rv)) {
    return false;
  }

  rv = regKey->WriteStringValue(NS_LITERAL_STRING("ProgId"), progId);
  if (NS_FAILED(rv)) {
    return false;
  }

  return IsAARDefault(pAAR, aClassName);
}

static void
SaveWin8RegistryHashes(bool aCheckAllTypes, bool* aIsDefaultBrowser)
{
  RefPtr<IApplicationAssociationRegistration> pAAR;
  HRESULT hr = CoCreateInstance(CLSID_ApplicationAssociationRegistration,
                                nullptr,
                                CLSCTX_INPROC,
                                IID_IApplicationAssociationRegistration,
                                getter_AddRefs(pAAR));
  if (FAILED(hr)) {
    return;
  }

  bool res = SaveWin8RegistryHash(pAAR, L"http");
  if (*aIsDefaultBrowser) {
    *aIsDefaultBrowser = res;
  }
  SaveWin8RegistryHash(pAAR, L"https");
  SaveWin8RegistryHash(pAAR, L"ftp");
  res = SaveWin8RegistryHash(pAAR, L".html");
  if (*aIsDefaultBrowser && aCheckAllTypes) {
    *aIsDefaultBrowser = res;
  }
  SaveWin8RegistryHash(pAAR, L".htm");
  SaveWin8RegistryHash(pAAR, L".shtml");
  SaveWin8RegistryHash(pAAR, L".xhtml");
  SaveWin8RegistryHash(pAAR, L".xht");
}

static bool
RestoreWin8RegistryHashes(bool aClaimAllTypes)
{
  RefPtr<IApplicationAssociationRegistration> pAAR;
  HRESULT hr = CoCreateInstance(CLSID_ApplicationAssociationRegistration,
                                nullptr,
                                CLSCTX_INPROC,
                                IID_IApplicationAssociationRegistration,
                                getter_AddRefs(pAAR));
  if (FAILED(hr)) {
    return false;
  }

  bool res = RestoreWin8RegistryHash(pAAR, L"http");
  res = RestoreWin8RegistryHash(pAAR, L"https") && res;
  RestoreWin8RegistryHash(pAAR, L"ftp");
  bool res2 = RestoreWin8RegistryHash(pAAR, L".html");
  res2 = RestoreWin8RegistryHash(pAAR, L".htm") && res2;
  if (aClaimAllTypes) {
    res = res && res2;
  }
  RestoreWin8RegistryHash(pAAR, L".shtml");
  RestoreWin8RegistryHash(pAAR, L".xhtml");
  RestoreWin8RegistryHash(pAAR, L".xht");

  return res;
}

/*
 * Query's the AAR for the default status.
 * This only checks for PaleMoonURL and if aCheckAllTypes is set, then
 * it also checks for PaleMoonHTML.  Note that those ProgIDs are shared
 * by all PaleMoon browsers.
*/
bool
nsWindowsShellService::IsDefaultBrowserVista(bool aCheckAllTypes,
                                             bool* aIsDefaultBrowser)
{
  RefPtr<IApplicationAssociationRegistration> pAAR;
  HRESULT hr = CoCreateInstance(CLSID_ApplicationAssociationRegistration,
                                nullptr,
                                CLSCTX_INPROC,
                                IID_IApplicationAssociationRegistration,
                                getter_AddRefs(pAAR));
  if (FAILED(hr)) {
    return false;
  }

  if (aCheckAllTypes) {
    BOOL res;
    hr = pAAR->QueryAppIsDefaultAll(AL_EFFECTIVE,
                                    APP_REG_NAME,
                                    &res);
    *aIsDefaultBrowser = res;
  } else if (!IsWin8OrLater()) {
    *aIsDefaultBrowser = IsAARDefault(pAAR, L"http");
  }

  return true;
}

NS_IMETHODIMP
nsWindowsShellService::IsDefaultBrowser(bool aStartupCheck,
                                        bool aForAllTypes,
                                        bool* aIsDefaultBrowser)
{
  // Assume we're the default unless one of the several checks below tell us
  // otherwise.
  *aIsDefaultBrowser = true;

  wchar_t exePath[MAX_BUF];
  if (!::GetModuleFileNameW(0, exePath, MAX_BUF))
    return NS_ERROR_FAILURE;

  // Convert the path to a long path since GetModuleFileNameW returns the path
  // that was used to launch PaleMoon which is not necessarily a long path.
  if (!::GetLongPathNameW(exePath, exePath, MAX_BUF))
    return NS_ERROR_FAILURE;

  nsAutoString appLongPath(exePath);

  HKEY theKey;
  DWORD res;
  nsresult rv;
  wchar_t currValue[MAX_BUF];

  SETTING* settings = gSettings;
  if (!aForAllTypes && IsWin8OrLater()) {
    // Skip over the file handler check
    settings++;
  }

  SETTING* end = gSettings + sizeof(gSettings) / sizeof(SETTING);

  for (; settings < end; ++settings) {
    NS_ConvertUTF8toUTF16 keyName(settings->keyName);
    NS_ConvertUTF8toUTF16 valueData(settings->valueData);
    int32_t offset = valueData.Find("%APPPATH%");
    valueData.Replace(offset, 9, appLongPath);

    rv = OpenKeyForReading(HKEY_CLASSES_ROOT, keyName, &theKey);
    if (NS_FAILED(rv)) {
      *aIsDefaultBrowser = false;
      return NS_OK;
    }

    ::ZeroMemory(currValue, sizeof(currValue));
    DWORD len = sizeof currValue;
    res = ::RegQueryValueExW(theKey, L"", nullptr, nullptr,
                             (LPBYTE)currValue, &len);
    // Close the key that was opened.
    ::RegCloseKey(theKey);
    if (REG_FAILED(res) ||
        _wcsicmp(valueData.get(), currValue)) {
      // Key wasn't set or was set to something other than our registry entry.
      NS_ConvertUTF8toUTF16 oldValueData(settings->oldValueData);
      offset = oldValueData.Find("%APPPATH%");
      oldValueData.Replace(offset, 9, appLongPath);
      // The current registry value doesn't match the current or the old format.
      if (_wcsicmp(oldValueData.get(), currValue)) {
        *aIsDefaultBrowser = false;
        return NS_OK;
      }

      res = ::RegOpenKeyExW(HKEY_CLASSES_ROOT, PromiseFlatString(keyName).get(),
                            0, KEY_SET_VALUE, &theKey);
      if (REG_FAILED(res)) {
        // If updating the open command fails try to update it using the helper
        // application when setting PaleMoon as the default browser.
        *aIsDefaultBrowser = false;
        return NS_OK;
      }

      const nsString &flatValue = PromiseFlatString(valueData);
      res = ::RegSetValueExW(theKey, L"", 0, REG_SZ,
                             (const BYTE *) flatValue.get(),
                             (flatValue.Length() + 1) * sizeof(char16_t));
      // Close the key that was created.
      ::RegCloseKey(theKey);
      if (REG_FAILED(res)) {
        // If updating the open command fails try to update it using the helper
        // application when setting PaleMoon as the default browser.
        *aIsDefaultBrowser = false;
        return NS_OK;
      }
    }
  }

  // Only check if PaleMoon is the default browser on Vista and above if the
  // previous checks show that PaleMoon is the default browser.
  if (*aIsDefaultBrowser) {
    if (IsWin8OrLater()) {
      SaveWin8RegistryHashes(aForAllTypes, aIsDefaultBrowser);
    }
  }

  // To handle the case where DDE isn't disabled due for a user because there
  // account didn't perform a PaleMoon update this will check if PaleMoon is the
  // default browser and if dde is disabled for each handler
  // and if it isn't disable it. When PaleMoon is not the default browser the
  // helper application will disable dde for each handler.
  if (*aIsDefaultBrowser && aForAllTypes) {
    // Check ftp settings

    end = gDDESettings + sizeof(gDDESettings) / sizeof(SETTING);

    for (settings = gDDESettings; settings < end; ++settings) {
      NS_ConvertUTF8toUTF16 keyName(settings->keyName);

      rv = OpenKeyForReading(HKEY_CURRENT_USER, keyName, &theKey);
      if (NS_FAILED(rv)) {
        ::RegCloseKey(theKey);
        // If disabling DDE fails try to disable it using the helper
        // application when setting PaleMoon as the default browser.
        *aIsDefaultBrowser = false;
        return NS_OK;
      }

      ::ZeroMemory(currValue, sizeof(currValue));
      DWORD len = sizeof currValue;
      res = ::RegQueryValueExW(theKey, L"", nullptr, nullptr,
                               (LPBYTE)currValue, &len);
      // Close the key that was opened.
      ::RegCloseKey(theKey);
      if (REG_FAILED(res) || char16_t('\0') != *currValue) {
        // Key wasn't set or was set to something other than our registry entry.
        // Delete the key along with all of its childrean and then recreate it.
        const nsString &flatName = PromiseFlatString(keyName);
        ::SHDeleteKeyW(HKEY_CURRENT_USER, flatName.get());
        res = ::RegCreateKeyExW(HKEY_CURRENT_USER, flatName.get(), 0, nullptr,
                                REG_OPTION_NON_VOLATILE, KEY_SET_VALUE,
                                nullptr, &theKey, nullptr);
        if (REG_FAILED(res)) {
          // If disabling DDE fails try to disable it using the helper
          // application when setting PaleMoon as the default browser.
          *aIsDefaultBrowser = false;
          return NS_OK;
        }

        res = ::RegSetValueExW(theKey, L"", 0, REG_SZ, (const BYTE *) L"",
                               sizeof(char16_t));
        // Close the key that was created.
        ::RegCloseKey(theKey);
        if (REG_FAILED(res)) {
          // If disabling DDE fails try to disable it using the helper
          // application when setting PaleMoon as the default browser.
          *aIsDefaultBrowser = false;
          return NS_OK;
        }
      }
    }

    // Update the FTP protocol handler's shell open command if it is the old
    // format.
    res = ::RegOpenKeyExW(HKEY_CURRENT_USER, FTP_SOC, 0, KEY_ALL_ACCESS,
                          &theKey);
    // Don't update the FTP protocol handler's shell open command when opening
    // its registry key fails under HKCU since it most likely doesn't exist.
    if (NS_FAILED(rv)) {
      return NS_OK;
    }

    NS_ConvertUTF8toUTF16 oldValueOpen(OLD_VAL_OPEN);
    int32_t offset = oldValueOpen.Find("%APPPATH%");
    oldValueOpen.Replace(offset, 9, appLongPath);

    ::ZeroMemory(currValue, sizeof(currValue));
    DWORD len = sizeof currValue;
    res = ::RegQueryValueExW(theKey, L"", nullptr, nullptr, (LPBYTE)currValue,
                             &len);

    // Don't update the FTP protocol handler's shell open command when the
    // current registry value doesn't exist or matches the old format.
    if (REG_FAILED(res) ||
        _wcsicmp(oldValueOpen.get(), currValue)) {
      ::RegCloseKey(theKey);
      return NS_OK;
    }

    NS_ConvertUTF8toUTF16 valueData(VAL_OPEN);
    valueData.Replace(offset, 9, appLongPath);
    const nsString &flatValue = PromiseFlatString(valueData);
    res = ::RegSetValueExW(theKey, L"", 0, REG_SZ,
                           (const BYTE *) flatValue.get(),
                           (flatValue.Length() + 1) * sizeof(char16_t));
    // Close the key that was created.
    ::RegCloseKey(theKey);
    // If updating the FTP protocol handlers shell open command fails try to
    // update it using the helper application when setting PaleMoon as the
    // default browser.
    if (REG_FAILED(res)) {
      *aIsDefaultBrowser = false;
    }
  }

  return NS_OK;
}

static nsresult
DynSHOpenWithDialog(HWND hwndParent, const OPENASINFO *poainfo)
{
  // shell32.dll is in the knownDLLs list so will always be loaded from the
  // system32 directory.
  static const wchar_t kSehllLibraryName[] =  L"shell32.dll";
  HMODULE shellDLL = ::LoadLibraryW(kSehllLibraryName);
  if (!shellDLL) {
    return NS_ERROR_FAILURE;
  }

  decltype(SHOpenWithDialog)* SHOpenWithDialogFn =
    (decltype(SHOpenWithDialog)*) GetProcAddress(shellDLL, "SHOpenWithDialog");

  if (!SHOpenWithDialogFn) {
    return NS_ERROR_FAILURE;
  }

  nsresult rv = 
    SUCCEEDED(SHOpenWithDialogFn(hwndParent, poainfo)) ? NS_OK :
                                                         NS_ERROR_FAILURE;
  FreeLibrary(shellDLL);
  return rv;
}

nsresult
nsWindowsShellService::LaunchControlPanelDefaultsSelectionUI()
{
  IApplicationAssociationRegistrationUI* pAARUI;
  HRESULT hr = CoCreateInstance(CLSID_ApplicationAssociationRegistrationUI,
                                NULL,
                                CLSCTX_INPROC,
                                IID_IApplicationAssociationRegistrationUI,
                                (void**)&pAARUI);
  if (SUCCEEDED(hr)) {
    hr = pAARUI->LaunchAdvancedAssociationUI(APP_REG_NAME);
    pAARUI->Release();
  }
  return SUCCEEDED(hr) ? NS_OK : NS_ERROR_FAILURE;
}

nsresult
nsWindowsShellService::LaunchControlPanelDefaultPrograms()
{
  // Default Programs is a Vista+ feature
  if (!IsVistaOrLater()) {
    return NS_ERROR_FAILURE;
  }

  // Build the path control.exe path safely
  WCHAR controlEXEPath[MAX_PATH + 1] = { '\0' };
  if (!GetSystemDirectoryW(controlEXEPath, MAX_PATH)) {
    return NS_ERROR_FAILURE;
  }
  LPCWSTR controlEXE = L"control.exe";
  if (wcslen(controlEXEPath) + wcslen(controlEXE) >= MAX_PATH) {
    return NS_ERROR_FAILURE;
  }
  if (!PathAppendW(controlEXEPath, controlEXE)) {
    return NS_ERROR_FAILURE;
  }

  WCHAR params[] = L"control.exe /name Microsoft.DefaultPrograms /page pageDefaultProgram";
  STARTUPINFOW si = {sizeof(si), 0};
  si.dwFlags = STARTF_USESHOWWINDOW;
  si.wShowWindow = SW_SHOWDEFAULT;
  PROCESS_INFORMATION pi = {0};
  if (!CreateProcessW(controlEXEPath, params, nullptr, nullptr, FALSE,
                      0, nullptr, nullptr, &si, &pi)) {
    return NS_ERROR_FAILURE;
  }
  CloseHandle(pi.hProcess);
  CloseHandle(pi.hThread);

  return NS_OK;
}

static bool
IsWindowsLogonConnected()
{
  WCHAR userName[UNLEN + 1];
  DWORD size = ArrayLength(userName);
  if (!GetUserNameW(userName, &size)) {
    return false;
  }

  LPUSER_INFO_24 info;
  if (NetUserGetInfo(nullptr, userName, 24, (LPBYTE *)&info)
      != NERR_Success) {
    return false;
  }
  bool connected = info->usri24_internet_identity;
  NetApiBufferFree(info);

  return connected;
}

static bool
SettingsAppBelievesConnected()
{
  nsresult rv;
  nsCOMPtr<nsIWindowsRegKey> regKey =
    do_CreateInstance("@mozilla.org/windows-registry-key;1", &rv);
  if (NS_FAILED(rv)) {
    return false;
  }

  rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
                    NS_LITERAL_STRING("SOFTWARE\\Microsoft\\Windows\\Shell\\Associations"),
                    nsIWindowsRegKey::ACCESS_READ);
  if (NS_FAILED(rv)) {
    return false;
  }

  uint32_t value;
  rv = regKey->ReadIntValue(NS_LITERAL_STRING("IsConnectedAtLogon"), &value);
  if (NS_FAILED(rv)) {
    return false;
  }

  return !!value;
}

nsresult
nsWindowsShellService::LaunchModernSettingsDialogDefaultApps()
{
  if (!IsWindowsLogonConnected() && SettingsAppBelievesConnected()) {
    // Use the classic Control Panel to work around a bug of Windows 10.
    return LaunchControlPanelDefaultPrograms();
  }

  IApplicationActivationManager* pActivator;
  HRESULT hr = CoCreateInstance(CLSID_ApplicationActivationManager,
                                nullptr,
                                CLSCTX_INPROC,
                                IID_IApplicationActivationManager,
                                (void**)&pActivator);

  if (SUCCEEDED(hr)) {
    DWORD pid;
    hr = pActivator->ActivateApplication(
           L"windows.immersivecontrolpanel_cw5n1h2txyewy"
           L"!microsoft.windows.immersivecontrolpanel",
           L"page=SettingsPageAppsDefaults", AO_NONE, &pid);
    pActivator->Release();
    return SUCCEEDED(hr) ? NS_OK : NS_ERROR_FAILURE;
  }
  return NS_OK;
}

nsresult
nsWindowsShellService::InvokeHTTPOpenAsVerb()
{
  nsCOMPtr<nsIURLFormatter> formatter(
    do_GetService("@mozilla.org/toolkit/URLFormatterService;1"));
  if (!formatter) {
    return NS_ERROR_UNEXPECTED;
  }

  nsString urlStr;
  nsresult rv = formatter->FormatURLPref(
    NS_LITERAL_STRING("app.support.baseURL"), urlStr);
  if (NS_FAILED(rv)) {
    return rv;
  }
  if (!StringBeginsWith(urlStr, NS_LITERAL_STRING("https://"))) {
    return NS_ERROR_FAILURE;
  }
  urlStr.AppendLiteral("win10-default-browser");

  SHELLEXECUTEINFOW seinfo = { sizeof(SHELLEXECUTEINFOW) };
  seinfo.lpVerb = L"openas";
  seinfo.lpFile = urlStr.get();
  seinfo.nShow = SW_SHOWNORMAL;
  if (!ShellExecuteExW(&seinfo)) {
    return NS_ERROR_FAILURE;
  }
  return NS_OK;
}

nsresult
nsWindowsShellService::LaunchHTTPHandlerPane()
{
  OPENASINFO info;
  info.pcszFile = L"http";
  info.pcszClass = nullptr;
  info.oaifInFlags = OAIF_FORCE_REGISTRATION | 
                     OAIF_URL_PROTOCOL |
                     OAIF_REGISTER_EXT;
  return DynSHOpenWithDialog(nullptr, &info);
}

NS_IMETHODIMP
nsWindowsShellService::SetDefaultBrowser(bool aClaimAllTypes, bool aForAllUsers)
{
  nsAutoString appHelperPath;
  if (NS_FAILED(GetHelperPath(appHelperPath)))
    return NS_ERROR_FAILURE;

  if (aForAllUsers) {
    appHelperPath.AppendLiteral(" /SetAsDefaultAppGlobal");
  } else {
    appHelperPath.AppendLiteral(" /SetAsDefaultAppUser");
  }

  nsresult rv = LaunchHelper(appHelperPath);
  if (NS_SUCCEEDED(rv) && IsWin8OrLater() &&
      !RestoreWin8RegistryHashes(aClaimAllTypes)) {
    if (aClaimAllTypes) {
      if (IsWin10OrLater()) {
        rv = LaunchModernSettingsDialogDefaultApps();
      } else {
        rv = LaunchControlPanelDefaultsSelectionUI();
      }
      // The above call should never really fail, but just in case
      // fall back to showing the HTTP association screen only.
      if (NS_FAILED(rv)) {
        if (IsWin10OrLater()) {
          rv = InvokeHTTPOpenAsVerb();
        } else {
          rv = LaunchHTTPHandlerPane();
        }
      }
    } else {
      // Windows 10 blocks attempts to load the
      // HTTP Handler association dialog.
      if (IsWin10OrLater()) {
        rv = LaunchModernSettingsDialogDefaultApps();
      } else {
        rv = LaunchHTTPHandlerPane();
      }

      // The above call should never really fail, but just in case
      // fall back to showing control panel for all defaults
      if (NS_FAILED(rv)) {
        rv = LaunchControlPanelDefaultsSelectionUI();
      }
      bool isDefault;
      SaveWin8RegistryHashes(aClaimAllTypes, &isDefault);
    }
  }

  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
  if (prefs) {
    (void) prefs->SetBoolPref(PREF_CHECKDEFAULTBROWSER, true);
    // Reset the number of times the dialog should be shown
    // before it is silenced.
    (void) prefs->SetIntPref(PREF_DEFAULTBROWSERCHECKCOUNT, 0);
  }

  return rv;
}

static nsresult
WriteBitmap(nsIFile* aFile, imgIContainer* aImage)
{
  nsresult rv;

  RefPtr<SourceSurface> surface =
    aImage->GetFrame(imgIContainer::FRAME_FIRST,
                     imgIContainer::FLAG_SYNC_DECODE);
  NS_ENSURE_TRUE(surface, NS_ERROR_FAILURE);

  // For either of the following formats we want to set the biBitCount member
  // of the BITMAPINFOHEADER struct to 32, below. For that value the bitmap
  // format defines that the A8/X8 WORDs in the bitmap byte stream be ignored
  // for the BI_RGB value we use for the biCompression member.
  MOZ_ASSERT(surface->GetFormat() == SurfaceFormat::B8G8R8A8 ||
             surface->GetFormat() == SurfaceFormat::B8G8R8X8);

  RefPtr<DataSourceSurface> dataSurface = surface->GetDataSurface();
  NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);

  int32_t width = dataSurface->GetSize().width;
  int32_t height = dataSurface->GetSize().height;
  int32_t bytesPerPixel = 4 * sizeof(uint8_t);
  uint32_t bytesPerRow = bytesPerPixel * width;

  // initialize these bitmap structs which we will later
  // serialize directly to the head of the bitmap file
  BITMAPINFOHEADER bmi;
  bmi.biSize = sizeof(BITMAPINFOHEADER);
  bmi.biWidth = width;
  bmi.biHeight = height;
  bmi.biPlanes = 1;
  bmi.biBitCount = (WORD)bytesPerPixel*8;
  bmi.biCompression = BI_RGB;
  bmi.biSizeImage = bytesPerRow * height;
  bmi.biXPelsPerMeter = 0;
  bmi.biYPelsPerMeter = 0;
  bmi.biClrUsed = 0;
  bmi.biClrImportant = 0;

  BITMAPFILEHEADER bf;
  bf.bfType = 0x4D42; // 'BM'
  bf.bfReserved1 = 0;
  bf.bfReserved2 = 0;
  bf.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
  bf.bfSize = bf.bfOffBits + bmi.biSizeImage;

  // get a file output stream
  nsCOMPtr<nsIOutputStream> stream;
  rv = NS_NewLocalFileOutputStream(getter_AddRefs(stream), aFile);
  NS_ENSURE_SUCCESS(rv, rv);

  DataSourceSurface::MappedSurface map;
  if (!dataSurface->Map(DataSourceSurface::MapType::READ, &map)) {
    return NS_ERROR_FAILURE;
  }

  // write the bitmap headers and rgb pixel data to the file
  rv = NS_ERROR_FAILURE;
  if (stream) {
    uint32_t written;
    stream->Write((const char*)&bf, sizeof(BITMAPFILEHEADER), &written);
    if (written == sizeof(BITMAPFILEHEADER)) {
      stream->Write((const char*)&bmi, sizeof(BITMAPINFOHEADER), &written);
      if (written == sizeof(BITMAPINFOHEADER)) {
        // write out the image data backwards because the desktop won't
        // show bitmaps with negative heights for top-to-bottom
        uint32_t i = map.mStride * height;
        do {
          i -= map.mStride;
          stream->Write(((const char*)map.mData) + i, bytesPerRow, &written);
          if (written == bytesPerRow) {
            rv = NS_OK;
          } else {
            rv = NS_ERROR_FAILURE;
            break;
          }
        } while (i != 0);
      }
    }

    stream->Close();
  }

  dataSurface->Unmap();

  return rv;
}

NS_IMETHODIMP
nsWindowsShellService::SetDesktopBackground(nsIDOMElement* aElement, 
                                            int32_t aPosition)
{
  nsresult rv;

  nsCOMPtr<imgIContainer> container;
  nsCOMPtr<nsIDOMHTMLImageElement> imgElement(do_QueryInterface(aElement));
  if (!imgElement) {
    // XXX write background loading stuff!
    return NS_ERROR_NOT_AVAILABLE;
  } 
  else {
    nsCOMPtr<nsIImageLoadingContent> imageContent =
      do_QueryInterface(aElement, &rv);
    if (!imageContent)
      return rv;

    // get the image container
    nsCOMPtr<imgIRequest> request;
    rv = imageContent->GetRequest(nsIImageLoadingContent::CURRENT_REQUEST,
                                  getter_AddRefs(request));
    if (!request)
      return rv;
    rv = request->GetImage(getter_AddRefs(container));
    if (!container)
      return NS_ERROR_FAILURE;
  }

  // get the file name from localized strings
  nsCOMPtr<nsIStringBundleService>
    bundleService(do_GetService(NS_STRINGBUNDLE_CONTRACTID, &rv));
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIStringBundle> shellBundle;
  rv = bundleService->CreateBundle(SHELLSERVICE_PROPERTIES,
                                   getter_AddRefs(shellBundle));
  NS_ENSURE_SUCCESS(rv, rv);
 
  // e.g. "Desktop Background.bmp"
  nsString fileLeafName;
  rv = shellBundle->GetStringFromName
                      (MOZ_UTF16("desktopBackgroundLeafNameWin"),
                       getter_Copies(fileLeafName));
  NS_ENSURE_SUCCESS(rv, rv);

  // get the profile root directory
  nsCOMPtr<nsIFile> file;
  rv = NS_GetSpecialDirectory(NS_APP_APPLICATION_REGISTRY_DIR,
                              getter_AddRefs(file));
  NS_ENSURE_SUCCESS(rv, rv);

  // eventually, the path is "%APPDATA%\Mozilla\PaleMoon\Desktop Background.bmp"
  rv = file->Append(fileLeafName);
  NS_ENSURE_SUCCESS(rv, rv);

  nsAutoString path;
  rv = file->GetPath(path);
  NS_ENSURE_SUCCESS(rv, rv);

  // write the bitmap to a file in the profile directory
  rv = WriteBitmap(file, container);

  // if the file was written successfully, set it as the system wallpaper
  if (NS_SUCCEEDED(rv)) {
    nsCOMPtr<nsIWindowsRegKey> regKey =
      do_CreateInstance("@mozilla.org/windows-registry-key;1", &rv);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = regKey->Create(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
                        NS_LITERAL_STRING("Control Panel\\Desktop"),
                        nsIWindowsRegKey::ACCESS_SET_VALUE);
    NS_ENSURE_SUCCESS(rv, rv);

    nsAutoString tile;
    nsAutoString style;
    switch (aPosition) {
      case BACKGROUND_TILE:
        style.AssignLiteral("0");
        tile.AssignLiteral("1");
        break;
      case BACKGROUND_CENTER:
        style.AssignLiteral("0");
        tile.AssignLiteral("0");
        break;
      case BACKGROUND_STRETCH:
        style.AssignLiteral("2");
        tile.AssignLiteral("0");
        break;
      case BACKGROUND_FILL:
        style.AssignLiteral("10");
        tile.AssignLiteral("0");
        break;
      case BACKGROUND_FIT:
        style.AssignLiteral("6");
        tile.AssignLiteral("0");
        break;
    }

    rv = regKey->WriteStringValue(NS_LITERAL_STRING("TileWallpaper"), tile);
    NS_ENSURE_SUCCESS(rv, rv);
    rv = regKey->WriteStringValue(NS_LITERAL_STRING("WallpaperStyle"), style);
    NS_ENSURE_SUCCESS(rv, rv);
    rv = regKey->Close();
    NS_ENSURE_SUCCESS(rv, rv);

    ::SystemParametersInfoW(SPI_SETDESKWALLPAPER, 0, (PVOID)path.get(),
                            SPIF_UPDATEINIFILE | SPIF_SENDCHANGE);
  }
  return rv;
}

NS_IMETHODIMP
nsWindowsShellService::OpenApplication(int32_t aApplication)
{
  nsAutoString application;
  switch (aApplication) {
  case nsIShellService::APPLICATION_MAIL:
    application.AssignLiteral("Mail");
    break;
  case nsIShellService::APPLICATION_NEWS:
    application.AssignLiteral("News");
    break;
  }

  // The Default Client section of the Windows Registry looks like this:
  // 
  // Clients\aClient\
  //  e.g. aClient = "Mail"...
  //        \Mail\(default) = Client Subkey Name
  //             \Client Subkey Name
  //             \Client Subkey Name\shell\open\command\ 
  //             \Client Subkey Name\shell\open\command\(default) = path to exe
  //

  // Find the default application for this class.
  HKEY theKey;
  nsresult rv = OpenKeyForReading(HKEY_CLASSES_ROOT, application, &theKey);
  if (NS_FAILED(rv))
    return rv;

  wchar_t buf[MAX_BUF];
  DWORD type, len = sizeof buf;
  DWORD res = ::RegQueryValueExW(theKey, EmptyString().get(), 0,
                                 &type, (LPBYTE)&buf, &len);

  if (REG_FAILED(res) || !*buf)
    return NS_OK;

  // Close the key we opened.
  ::RegCloseKey(theKey);

  // Find the "open" command
  application.AppendLiteral("\\");
  application.Append(buf);
  application.AppendLiteral("\\shell\\open\\command");

  rv = OpenKeyForReading(HKEY_CLASSES_ROOT, application, &theKey);
  if (NS_FAILED(rv))
    return rv;

  ::ZeroMemory(buf, sizeof(buf));
  len = sizeof buf;
  res = ::RegQueryValueExW(theKey, EmptyString().get(), 0,
                           &type, (LPBYTE)&buf, &len);
  if (REG_FAILED(res) || !*buf)
    return NS_ERROR_FAILURE;

  // Close the key we opened.
  ::RegCloseKey(theKey);

  // Look for any embedded environment variables and substitute their 
  // values, as |::CreateProcessW| is unable to do this.
  nsAutoString path(buf);
  int32_t end = path.Length();
  int32_t cursor = 0, temp = 0;
  ::ZeroMemory(buf, sizeof(buf));
  do {
    cursor = path.FindChar('%', cursor);
    if (cursor < 0) 
      break;

    temp = path.FindChar('%', cursor + 1);
    ++cursor;

    ::ZeroMemory(&buf, sizeof(buf));

    ::GetEnvironmentVariableW(nsAutoString(Substring(path, cursor, temp - cursor)).get(),
                              buf, sizeof(buf));
    
    // "+ 2" is to subtract the extra characters used to delimit the environment
    // variable ('%').
    path.Replace((cursor - 1), temp - cursor + 2, nsDependentString(buf));

    ++cursor;
  }
  while (cursor < end);

  STARTUPINFOW si;
  PROCESS_INFORMATION pi;

  ::ZeroMemory(&si, sizeof(STARTUPINFOW));
  ::ZeroMemory(&pi, sizeof(PROCESS_INFORMATION));

  BOOL success = ::CreateProcessW(nullptr, (LPWSTR)path.get(), nullptr,
                                  nullptr, FALSE, 0, nullptr,  nullptr,
                                  &si, &pi);
  if (!success)
    return NS_ERROR_FAILURE;

  return NS_OK;
}

NS_IMETHODIMP
nsWindowsShellService::GetDesktopBackgroundColor(uint32_t* aColor)
{
  uint32_t color = ::GetSysColor(COLOR_DESKTOP);
  *aColor = (GetRValue(color) << 16) | (GetGValue(color) << 8) | GetBValue(color);
  return NS_OK;
}

NS_IMETHODIMP
nsWindowsShellService::SetDesktopBackgroundColor(uint32_t aColor)
{
  int aParameters[2] = { COLOR_BACKGROUND, COLOR_DESKTOP };
  BYTE r = (aColor >> 16);
  BYTE g = (aColor << 16) >> 24;
  BYTE b = (aColor << 24) >> 24;
  COLORREF colors[2] = { RGB(r,g,b), RGB(r,g,b) };

  ::SetSysColors(sizeof(aParameters) / sizeof(int), aParameters, colors);

  nsresult rv;
  nsCOMPtr<nsIWindowsRegKey> regKey =
    do_CreateInstance("@mozilla.org/windows-registry-key;1", &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = regKey->Create(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
                      NS_LITERAL_STRING("Control Panel\\Colors"),
                      nsIWindowsRegKey::ACCESS_SET_VALUE);
  NS_ENSURE_SUCCESS(rv, rv);

  wchar_t rgb[12];
  _snwprintf(rgb, 12, L"%u %u %u", r, g, b);

  rv = regKey->WriteStringValue(NS_LITERAL_STRING("Background"),
                                nsDependentString(rgb));
  NS_ENSURE_SUCCESS(rv, rv);

  return regKey->Close();
}

nsWindowsShellService::nsWindowsShellService()
{
}

nsWindowsShellService::~nsWindowsShellService()
{
}

NS_IMETHODIMP
nsWindowsShellService::OpenApplicationWithURI(nsIFile* aApplication,
                                              const nsACString& aURI)
{
  nsresult rv;
  nsCOMPtr<nsIProcess> process = 
    do_CreateInstance("@mozilla.org/process/util;1", &rv);
  if (NS_FAILED(rv))
    return rv;
  
  rv = process->Init(aApplication);
  if (NS_FAILED(rv))
    return rv;
  
  const nsCString spec(aURI);
  const char* specStr = spec.get();
  return process->Run(false, &specStr, 1);
}

NS_IMETHODIMP
nsWindowsShellService::GetDefaultFeedReader(nsIFile** _retval)
{
  *_retval = nullptr;

  nsresult rv;
  nsCOMPtr<nsIWindowsRegKey> regKey =
    do_CreateInstance("@mozilla.org/windows-registry-key;1", &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
                    NS_LITERAL_STRING("feed\\shell\\open\\command"),
                    nsIWindowsRegKey::ACCESS_READ);
  NS_ENSURE_SUCCESS(rv, rv);

  nsAutoString path;
  rv = regKey->ReadStringValue(EmptyString(), path);
  NS_ENSURE_SUCCESS(rv, rv);
  if (path.IsEmpty())
    return NS_ERROR_FAILURE;

  if (path.First() == '"') {
    // Everything inside the quotes
    path = Substring(path, 1, path.FindChar('"', 1) - 1);
  }
  else {
    // Everything up to the first space
    path = Substring(path, 0, path.FindChar(' '));
  }

  nsCOMPtr<nsIFile> defaultReader =
    do_CreateInstance("@mozilla.org/file/local;1", &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = defaultReader->InitWithPath(path);
  NS_ENSURE_SUCCESS(rv, rv);

  bool exists;
  rv = defaultReader->Exists(&exists);
  NS_ENSURE_SUCCESS(rv, rv);
  if (!exists)
    return NS_ERROR_FAILURE;

  NS_ADDREF(*_retval = defaultReader);
  return NS_OK;
}