move browser to webbrowser/

1 files changed, 1277 insertions, 0 deletions

diff --git a/webbrowser/components/shell/nsWindowsShellService.cpp b/webbrowser/components/shell/nsWindowsShellService.cpp
new file mode 100644
index 0000000..c4039b9
--- /dev/null
+++ b/webbrowser/components/shell/nsWindowsShellService.cpp
@@ -0,0 +1,1277 @@
+/* -*- 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;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// 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\PaleMoon.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"PaleMoonURL" : L"PaleMoonHTML";
+  bool isDefault = !wcsicmp(registeredApp, progID);
+  CoTaskMemFree(registeredApp);
+
+  return isDefault;
+}
+
+static void
+IsDefaultBrowserWin8(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 = IsAARDefault(pAAR, L"http");
+  if (*aIsDefaultBrowser) {
+    *aIsDefaultBrowser = res;
+  }
+  res = IsAARDefault(pAAR, L".html");
+  if (*aIsDefaultBrowser && aCheckAllTypes) {
+    *aIsDefaultBrowser = 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) {
+    IsDefaultBrowserVista(aForAllTypes, aIsDefaultBrowser);
+    if (IsWin8OrLater()) {
+      IsDefaultBrowserWin8(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;
+  HRESULT hr = SHOpenWithDialogFn(hwndParent, poainfo);
+  if (SUCCEEDED(hr) || (hr == HRESULT_FROM_WIN32(ERROR_CANCELLED))) {
+    rv = NS_OK;
+  } else {
+    rv = 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()
+{
+  // 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\\pageAdvancedSettings?pszAppName=" APP_REG_NAME;
+  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 (!IsWindowsBuildOrLater(14965) &&
+      !IsWindowsLogonConnected() && SettingsAppBelievesConnected()) {
+    // Use the classic Control Panel to work around a bug of older
+    // builds 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);
+    if (SUCCEEDED(hr)) {
+      // Do not check error because we could at least open
+      // the "Default apps" setting.
+      pActivator->ActivateApplication(
+             L"windows.immersivecontrolpanel_cw5n1h2txyewy"
+             L"!microsoft.windows.immersivecontrolpanel",
+             L"page=SettingsPageAppsDefaults"
+             L"&target=SystemSettings_DefaultApps_Browser", 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()) {
+    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();
+      }
+    }
+  }
+
+  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
+                      (u"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.Assign('0');
+        tile.Assign('1');
+        break;
+      case BACKGROUND_CENTER:
+        style.Assign('0');
+        tile.Assign('0');
+        break;
+      case BACKGROUND_STRETCH:
+        style.Assign('2');
+        tile.Assign('0');
+        break;
+      case BACKGROUND_FILL:
+        style.AssignLiteral("10");
+        tile.Assign('0');
+        break;
+      case BACKGROUND_FIT:
+        style.Assign('6');
+        tile.Assign('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.Append('\\');
+  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;
+}