1 files changed, 626 insertions, 0 deletions
diff --git a/uriloader/exthandler/win/nsOSHelperAppService.cpp b/uriloader/exthandler/win/nsOSHelperAppService.cpp
new file mode 100644
index 0000000000..f01f3b49b5
--- /dev/null
+++ b/uriloader/exthandler/win/nsOSHelperAppService.cpp
@@ -0,0 +1,626 @@
+/* -*- Mode: C++; tab-width: 3; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim:set ts=2 sts=2 sw=2 et cin:
+ *
+ * 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 "nsOSHelperAppService.h"
+#include "nsISupports.h"
+#include "nsString.h"
+#include "nsXPIDLString.h"
+#include "nsIURL.h"
+#include "nsIMIMEInfo.h"
+#include "nsMIMEInfoWin.h"
+#include "nsMimeTypes.h"
+#include "nsIProcess.h"
+#include "plstr.h"
+#include "nsAutoPtr.h"
+#include "nsNativeCharsetUtils.h"
+#include "nsLocalFile.h"
+#include "nsIWindowsRegKey.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "mozilla/WindowsVersion.h"
+
+// shellapi.h is needed to build with WIN32_LEAN_AND_MEAN
+#include <shellapi.h>
+#include <shlwapi.h>
+
+#define LOG(args) MOZ_LOG(mLog, mozilla::LogLevel::Debug, args)
+
+// helper methods: forward declarations...
+static nsresult GetExtensionFrom4xRegistryInfo(const nsACString& aMimeType, 
+                                               nsString& aFileExtension);
+static nsresult GetExtensionFromWindowsMimeDatabase(const nsACString& aMimeType,
+                                                    nsString& aFileExtension);
+
+nsOSHelperAppService::nsOSHelperAppService() : 
+  nsExternalHelperAppService()
+  , mAppAssoc(nullptr)
+{
+  CoInitialize(nullptr);
+  CoCreateInstance(CLSID_ApplicationAssociationRegistration, nullptr,
+                   CLSCTX_INPROC, IID_IApplicationAssociationRegistration,
+                   (void**)&mAppAssoc);
+}
+
+nsOSHelperAppService::~nsOSHelperAppService()
+{
+  if (mAppAssoc)
+    mAppAssoc->Release();
+  mAppAssoc = nullptr;
+  CoUninitialize();
+}
+
+// The windows registry provides a mime database key which lists a set of mime types and corresponding "Extension" values. 
+// we can use this to look up our mime type to see if there is a preferred extension for the mime type.
+static nsresult GetExtensionFromWindowsMimeDatabase(const nsACString& aMimeType,
+                                                    nsString& aFileExtension)
+{
+  nsAutoString mimeDatabaseKey;
+  mimeDatabaseKey.AssignLiteral("MIME\\Database\\Content Type\\");
+
+  AppendASCIItoUTF16(aMimeType, mimeDatabaseKey);
+
+  nsCOMPtr<nsIWindowsRegKey> regKey = 
+    do_CreateInstance("@mozilla.org/windows-registry-key;1");
+  if (!regKey) 
+    return NS_ERROR_NOT_AVAILABLE;
+
+  nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                             mimeDatabaseKey,
+                             nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+  
+  if (NS_SUCCEEDED(rv))
+     regKey->ReadStringValue(NS_LITERAL_STRING("Extension"), aFileExtension);
+
+  return NS_OK;
+}
+
+// We have a serious problem!! I have this content type and the windows registry only gives me
+// helper apps based on extension. Right now, we really don't have a good place to go for 
+// trying to figure out the extension for a particular mime type....One short term hack is to look
+// this information in 4.x (it's stored in the windows regsitry). 
+static nsresult GetExtensionFrom4xRegistryInfo(const nsACString& aMimeType,
+                                               nsString& aFileExtension)
+{
+  nsCOMPtr<nsIWindowsRegKey> regKey = 
+    do_CreateInstance("@mozilla.org/windows-registry-key;1");
+  if (!regKey) 
+    return NS_ERROR_NOT_AVAILABLE;
+
+  nsresult rv = regKey->
+    Open(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
+         NS_LITERAL_STRING("Software\\Netscape\\Netscape Navigator\\Suffixes"),
+         nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+  if (NS_FAILED(rv))
+    return NS_ERROR_NOT_AVAILABLE;
+   
+  rv = regKey->ReadStringValue(NS_ConvertASCIItoUTF16(aMimeType),
+                               aFileExtension);
+  if (NS_FAILED(rv))
+    return NS_OK;
+
+  aFileExtension.Insert(char16_t('.'), 0);
+      
+  // this may be a comma separated list of extensions...just take the 
+  // first one for now...
+
+  int32_t pos = aFileExtension.FindChar(char16_t(','));
+  if (pos > 0) {
+    // we have a comma separated list of types...
+    // truncate everything after the first comma (including the comma)
+    aFileExtension.Truncate(pos); 
+  }
+   
+  return NS_OK;
+}
+
+nsresult nsOSHelperAppService::OSProtocolHandlerExists(const char * aProtocolScheme, bool * aHandlerExists)
+{
+  // look up the protocol scheme in the windows registry....if we find a match then we have a handler for it...
+  *aHandlerExists = false;
+  if (aProtocolScheme && *aProtocolScheme)
+  {
+    // Vista: use new application association interface
+    if (mAppAssoc) {
+      wchar_t * pResult = nullptr;
+      NS_ConvertASCIItoUTF16 scheme(aProtocolScheme);
+      // We are responsible for freeing returned strings.
+      HRESULT hr = mAppAssoc->QueryCurrentDefault(scheme.get(),
+                                                  AT_URLPROTOCOL, AL_EFFECTIVE,
+                                                  &pResult);
+      if (SUCCEEDED(hr)) {
+        CoTaskMemFree(pResult);
+        *aHandlerExists = true;
+      }
+      return NS_OK;
+    }
+
+    HKEY hKey;
+    LONG err = ::RegOpenKeyExW(HKEY_CLASSES_ROOT,
+                               NS_ConvertASCIItoUTF16(aProtocolScheme).get(),
+                               0,
+                               KEY_QUERY_VALUE,
+                               &hKey);
+    if (err == ERROR_SUCCESS)
+    {
+      err = ::RegQueryValueExW(hKey, L"URL Protocol",
+                               nullptr, nullptr, nullptr, nullptr);
+      *aHandlerExists = (err == ERROR_SUCCESS);
+      // close the key
+      ::RegCloseKey(hKey);
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsOSHelperAppService::GetApplicationDescription(const nsACString& aScheme, nsAString& _retval)
+{
+  nsCOMPtr<nsIWindowsRegKey> regKey = 
+    do_CreateInstance("@mozilla.org/windows-registry-key;1");
+  if (!regKey) 
+    return NS_ERROR_NOT_AVAILABLE;
+
+  NS_ConvertASCIItoUTF16 buf(aScheme);
+
+  if (mozilla::IsWin8OrLater()) {
+    wchar_t result[1024];
+    DWORD resultSize = 1024;
+    HRESULT hr = AssocQueryString(0x1000 /* ASSOCF_IS_PROTOCOL */,
+                                  ASSOCSTR_FRIENDLYAPPNAME,
+                                  buf.get(),
+                                  NULL,
+                                  result,
+                                  &resultSize);
+    if (SUCCEEDED(hr)) {
+      _retval = result;
+      return NS_OK;
+    }
+  }
+
+  if (mAppAssoc) {
+    // Vista: use new application association interface
+    wchar_t * pResult = nullptr;
+    // We are responsible for freeing returned strings.
+    HRESULT hr = mAppAssoc->QueryCurrentDefault(buf.get(),
+                                                AT_URLPROTOCOL, AL_EFFECTIVE,
+                                                &pResult);
+    if (SUCCEEDED(hr)) {
+      nsCOMPtr<nsIFile> app;
+      nsAutoString appInfo(pResult);
+      CoTaskMemFree(pResult);
+      if (NS_SUCCEEDED(GetDefaultAppInfo(appInfo, _retval, getter_AddRefs(app))))
+        return NS_OK;
+    }
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsCOMPtr<nsIFile> app;
+  GetDefaultAppInfo(buf, _retval, getter_AddRefs(app));
+
+  if (!_retval.Equals(buf))
+    return NS_OK;
+
+  // Fall back to full path
+  buf.AppendLiteral("\\shell\\open\\command");
+  nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                             buf,
+                             nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+  if (NS_FAILED(rv))
+    return NS_ERROR_NOT_AVAILABLE;   
+   
+  rv = regKey->ReadStringValue(EmptyString(), _retval); 
+
+  return NS_SUCCEEDED(rv) ? NS_OK : NS_ERROR_NOT_AVAILABLE;
+}
+
+// GetMIMEInfoFromRegistry: This function obtains the values of some of the nsIMIMEInfo
+// attributes for the mimeType/extension associated with the input registry key.  The default
+// entry for that key is the name of a registry key under HKEY_CLASSES_ROOT.  The default
+// value for *that* key is the descriptive name of the type.  The EditFlags value is a binary
+// value; the low order bit of the third byte of which indicates that the user does not need
+// to be prompted.
+//
+// This function sets only the Description attribute of the input nsIMIMEInfo.
+/* static */
+nsresult nsOSHelperAppService::GetMIMEInfoFromRegistry(const nsAFlatString& fileType, nsIMIMEInfo *pInfo)
+{
+  nsresult rv = NS_OK;
+
+  NS_ENSURE_ARG(pInfo);
+  nsCOMPtr<nsIWindowsRegKey> regKey = 
+    do_CreateInstance("@mozilla.org/windows-registry-key;1");
+  if (!regKey) 
+    return NS_ERROR_NOT_AVAILABLE;
+
+  rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                    fileType, nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+  if (NS_FAILED(rv))
+    return NS_ERROR_FAILURE;
+ 
+  // OK, the default value here is the description of the type.
+  nsAutoString description;
+  rv = regKey->ReadStringValue(EmptyString(), description);
+  if (NS_SUCCEEDED(rv))
+    pInfo->SetDescription(description);
+
+  return NS_OK;
+}
+
+/////////////////////////////////////////////////////////////////////////////////////////////////
+// method overrides used to gather information from the windows registry for
+// various mime types. 
+////////////////////////////////////////////////////////////////////////////////////////////////
+
+/// Looks up the type for the extension aExt and compares it to aType
+/* static */ bool
+nsOSHelperAppService::typeFromExtEquals(const char16_t* aExt, const char *aType)
+{
+  if (!aType)
+    return false;
+  nsAutoString fileExtToUse;
+  if (aExt[0] != char16_t('.'))
+    fileExtToUse = char16_t('.');
+
+  fileExtToUse.Append(aExt);
+
+  bool eq = false;
+  nsCOMPtr<nsIWindowsRegKey> regKey = 
+    do_CreateInstance("@mozilla.org/windows-registry-key;1");
+  if (!regKey) 
+    return eq;
+
+  nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                             fileExtToUse,
+                             nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+  if (NS_FAILED(rv))
+      return eq;
+   
+  nsAutoString type;
+  rv = regKey->ReadStringValue(NS_LITERAL_STRING("Content Type"), type);
+  if (NS_SUCCEEDED(rv))
+     eq = type.EqualsASCII(aType);
+
+  return eq;
+}
+
+// The "real" name of a given helper app (as specified by the path to the 
+// executable file held in various registry keys) is stored n the VERSIONINFO
+// block in the file's resources. We need to find the path to the executable
+// and then retrieve the "FileDescription" field value from the file. 
+nsresult
+nsOSHelperAppService::GetDefaultAppInfo(const nsAString& aAppInfo,
+                                        nsAString& aDefaultDescription, 
+                                        nsIFile** aDefaultApplication)
+{
+  nsAutoString handlerCommand;
+
+  // If all else fails, use the file type key name, which will be 
+  // something like "pngfile" for .pngs, "WMVFile" for .wmvs, etc. 
+  aDefaultDescription = aAppInfo;
+  *aDefaultApplication = nullptr;
+
+  if (aAppInfo.IsEmpty())
+    return NS_ERROR_FAILURE;
+
+  // aAppInfo may be a file, file path, program id, or
+  // Applications reference -
+  // c:\dir\app.exe
+  // Applications\appfile.exe/dll (shell\open...)
+  // ProgID.progid (shell\open...)
+
+  nsAutoString handlerKeyName(aAppInfo);
+
+  nsCOMPtr<nsIWindowsRegKey> chkKey = 
+    do_CreateInstance("@mozilla.org/windows-registry-key;1");
+  if (!chkKey) 
+    return NS_ERROR_FAILURE;
+      
+  nsresult rv = chkKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                             handlerKeyName, 
+                             nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+  if (NS_FAILED(rv)) {
+    // It's a file system path to a handler 
+    handlerCommand.Assign(aAppInfo);
+  }
+  else {
+    handlerKeyName.AppendLiteral("\\shell\\open\\command");
+    nsCOMPtr<nsIWindowsRegKey> regKey = 
+      do_CreateInstance("@mozilla.org/windows-registry-key;1");
+    if (!regKey) 
+      return NS_ERROR_FAILURE;
+
+    nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                               handlerKeyName, 
+                               nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+    if (NS_FAILED(rv))
+      return NS_ERROR_FAILURE;
+     
+    // OK, the default value here is the description of the type.
+    rv = regKey->ReadStringValue(EmptyString(), handlerCommand);
+    if (NS_FAILED(rv)) {
+
+      // Check if there is a DelegateExecute string
+      nsAutoString delegateExecute;
+      rv = regKey->ReadStringValue(NS_LITERAL_STRING("DelegateExecute"), delegateExecute);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      // Look for InProcServer32
+      nsAutoString delegateExecuteRegPath;
+      delegateExecuteRegPath.AssignLiteral("CLSID\\");
+      delegateExecuteRegPath.Append(delegateExecute);
+      delegateExecuteRegPath.AppendLiteral("\\InProcServer32");
+      rv = chkKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                        delegateExecuteRegPath, 
+                        nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+      if (NS_SUCCEEDED(rv)) {
+        rv = chkKey->ReadStringValue(EmptyString(), handlerCommand);
+      }
+
+      if (NS_FAILED(rv)) {
+        // Look for LocalServer32
+        delegateExecuteRegPath.AssignLiteral("CLSID\\");
+        delegateExecuteRegPath.Append(delegateExecute);
+        delegateExecuteRegPath.AppendLiteral("\\LocalServer32");
+        rv = chkKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                          delegateExecuteRegPath, 
+                          nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+        NS_ENSURE_SUCCESS(rv, rv);
+        rv = chkKey->ReadStringValue(EmptyString(), handlerCommand);
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+    }
+  }
+
+  // XXX FIXME: If this fails, the UI will display the full command
+  // string.
+  // There are some rare cases this can happen - ["url.dll" -foo]
+  // for example won't resolve correctly to the system dir. The 
+  // subsequent launch of the helper app will work though.
+  nsCOMPtr<nsILocalFileWin> lf = new nsLocalFile();
+  rv = lf->InitWithCommandLine(handlerCommand);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // The "FileDescription" field contains the actual name of the application.
+  lf->GetVersionInfoField("FileDescription", aDefaultDescription);
+  lf.forget(aDefaultApplication);
+
+  return NS_OK;
+}
+
+already_AddRefed<nsMIMEInfoWin> nsOSHelperAppService::GetByExtension(const nsAFlatString& aFileExt, const char *aTypeHint)
+{
+  if (aFileExt.IsEmpty())
+    return nullptr;
+
+  // Determine the mime type.
+  nsAutoCString typeToUse;
+  if (aTypeHint && *aTypeHint) {
+    typeToUse.Assign(aTypeHint);
+  } else if (!GetMIMETypeFromOSForExtension(NS_ConvertUTF16toUTF8(aFileExt), typeToUse)) {
+    return nullptr;
+  }
+
+  RefPtr<nsMIMEInfoWin> mimeInfo = new nsMIMEInfoWin(typeToUse);
+
+  // windows registry assumes your file extension is going to include the '.',
+  // but our APIs expect it to not be there, so make sure we normalize that bit.
+  nsAutoString fileExtToUse;
+  if (aFileExt.First() != char16_t('.'))
+    fileExtToUse = char16_t('.');
+
+  fileExtToUse.Append(aFileExt);
+
+  // don't append the '.' for our APIs.
+  mimeInfo->AppendExtension(NS_ConvertUTF16toUTF8(Substring(fileExtToUse, 1)));
+  mimeInfo->SetPreferredAction(nsIMIMEInfo::useSystemDefault);
+
+  nsAutoString appInfo;
+  bool found;
+
+  // Retrieve the default application for this extension
+  if (mAppAssoc) {
+    // Vista: use the new application association COM interfaces
+    // for resolving helpers.
+    nsString assocType(fileExtToUse);
+    wchar_t * pResult = nullptr;
+    HRESULT hr = mAppAssoc->QueryCurrentDefault(assocType.get(),
+                                                AT_FILEEXTENSION, AL_EFFECTIVE,
+                                                &pResult);
+    if (SUCCEEDED(hr)) {
+      found = true;
+      appInfo.Assign(pResult);
+      CoTaskMemFree(pResult);
+    } 
+    else {
+      found = false;
+    }
+  } 
+  else
+  {
+    nsCOMPtr<nsIWindowsRegKey> regKey =
+      do_CreateInstance("@mozilla.org/windows-registry-key;1");
+    if (!regKey)
+      return nullptr;
+    nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                               fileExtToUse,
+                               nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+    if (NS_SUCCEEDED(rv)) {
+      found = NS_SUCCEEDED(regKey->ReadStringValue(EmptyString(),
+                                                   appInfo));
+    }
+  }
+
+  // Bug 358297 - ignore the default handler, force the user to choose app
+  if (appInfo.EqualsLiteral("XPSViewer.Document"))
+    found = false;
+
+  if (!found) {
+    return nullptr;
+  }
+
+  // Get other nsIMIMEInfo fields from registry, if possible.
+  nsAutoString defaultDescription;
+  nsCOMPtr<nsIFile> defaultApplication;
+  
+  if (NS_FAILED(GetDefaultAppInfo(appInfo, defaultDescription,
+                                  getter_AddRefs(defaultApplication)))) {
+    return nullptr;
+  }
+
+  mimeInfo->SetDefaultDescription(defaultDescription);
+  mimeInfo->SetDefaultApplicationHandler(defaultApplication);
+
+  // Grab the general description
+  GetMIMEInfoFromRegistry(appInfo, mimeInfo);
+
+  return mimeInfo.forget();
+}
+
+already_AddRefed<nsIMIMEInfo> nsOSHelperAppService::GetMIMEInfoFromOS(const nsACString& aMIMEType, const nsACString& aFileExt, bool *aFound)
+{
+  *aFound = true;
+
+  const nsCString& flatType = PromiseFlatCString(aMIMEType);
+  const nsCString& flatExt = PromiseFlatCString(aFileExt);
+
+  nsAutoString fileExtension;
+  /* XXX The Equals is a gross hack to wallpaper over the most common Win32
+   * extension issues caused by the fix for bug 116938.  See bug
+   * 120327, comment 271 for why this is needed.  Not even sure we
+   * want to remove this once we have fixed all this stuff to work
+   * right; any info we get from the OS on this type is pretty much
+   * useless....
+   * We'll do extension-based lookup for this type later in this function.
+   */
+  if (!aMIMEType.LowerCaseEqualsLiteral(APPLICATION_OCTET_STREAM)) {
+    // (1) try to use the windows mime database to see if there is a mapping to a file extension
+    // (2) try to see if we have some left over 4.x registry info we can peek at...
+    GetExtensionFromWindowsMimeDatabase(aMIMEType, fileExtension);
+    LOG(("Windows mime database: extension '%s'\n", fileExtension.get()));
+    if (fileExtension.IsEmpty()) {
+      GetExtensionFrom4xRegistryInfo(aMIMEType, fileExtension);
+      LOG(("4.x Registry: extension '%s'\n", fileExtension.get()));
+    }
+  }
+  // If we found an extension for the type, do the lookup
+  RefPtr<nsMIMEInfoWin> mi;
+  if (!fileExtension.IsEmpty())
+    mi = GetByExtension(fileExtension, flatType.get());
+  LOG(("Extension lookup on '%s' found: 0x%p\n", fileExtension.get(), mi.get()));
+
+  bool hasDefault = false;
+  if (mi) {
+    mi->GetHasDefaultHandler(&hasDefault);
+    // OK. We might have the case that |aFileExt| is a valid extension for the
+    // mimetype we were given. In that case, we do want to append aFileExt
+    // to the mimeinfo that we have. (E.g.: We are asked for video/mpeg and
+    // .mpg, but the primary extension for video/mpeg is .mpeg. But because
+    // .mpg is an extension for video/mpeg content, we want to append it)
+    if (!aFileExt.IsEmpty() && typeFromExtEquals(NS_ConvertUTF8toUTF16(flatExt).get(), flatType.get())) {
+      LOG(("Appending extension '%s' to mimeinfo, because its mimetype is '%s'\n",
+           flatExt.get(), flatType.get()));
+      bool extExist = false;
+      mi->ExtensionExists(aFileExt, &extExist);
+      if (!extExist)
+        mi->AppendExtension(aFileExt);
+    }
+  }
+  if (!mi || !hasDefault) {
+    RefPtr<nsMIMEInfoWin> miByExt =
+      GetByExtension(NS_ConvertUTF8toUTF16(aFileExt), flatType.get());
+    LOG(("Ext. lookup for '%s' found 0x%p\n", flatExt.get(), miByExt.get()));
+    if (!miByExt && mi)
+      return mi.forget();
+    if (miByExt && !mi) {
+      return miByExt.forget();
+    }
+    if (!miByExt && !mi) {
+      *aFound = false;
+      mi = new nsMIMEInfoWin(flatType);
+      if (!aFileExt.IsEmpty()) {
+        mi->AppendExtension(aFileExt);
+      }
+      
+      return mi.forget();
+    }
+
+    // if we get here, mi has no default app. copy from extension lookup.
+    nsCOMPtr<nsIFile> defaultApp;
+    nsAutoString desc;
+    miByExt->GetDefaultDescription(desc);
+
+    mi->SetDefaultDescription(desc);
+  }
+  return mi.forget();
+}
+
+NS_IMETHODIMP
+nsOSHelperAppService::GetProtocolHandlerInfoFromOS(const nsACString &aScheme,
+                                                   bool *found,
+                                                   nsIHandlerInfo **_retval)
+{
+  NS_ASSERTION(!aScheme.IsEmpty(), "No scheme was specified!");
+
+  nsresult rv = OSProtocolHandlerExists(nsPromiseFlatCString(aScheme).get(),
+                                        found);
+  if (NS_FAILED(rv))
+    return rv;
+
+  nsMIMEInfoWin *handlerInfo =
+    new nsMIMEInfoWin(aScheme, nsMIMEInfoBase::eProtocolInfo);
+  NS_ENSURE_TRUE(handlerInfo, NS_ERROR_OUT_OF_MEMORY);
+  NS_ADDREF(*_retval = handlerInfo);
+
+  if (!*found) {
+    // Code that calls this requires an object regardless if the OS has
+    // something for us, so we return the empty object.
+    return NS_OK;
+  }
+
+  nsAutoString desc;
+  GetApplicationDescription(aScheme, desc);
+  handlerInfo->SetDefaultDescription(desc);
+
+  return NS_OK;
+}
+
+bool
+nsOSHelperAppService::GetMIMETypeFromOSForExtension(const nsACString& aExtension,
+                                                    nsACString& aMIMEType)
+{
+  if (aExtension.IsEmpty())
+    return false;
+
+  // windows registry assumes your file extension is going to include the '.'.
+  // so make sure it's there...
+  nsAutoString fileExtToUse;
+  if (aExtension.First() != '.')
+    fileExtToUse = char16_t('.');
+
+  AppendUTF8toUTF16(aExtension, fileExtToUse);
+
+  // Try to get an entry from the windows registry.
+  nsCOMPtr<nsIWindowsRegKey> regKey =
+    do_CreateInstance("@mozilla.org/windows-registry-key;1");
+  if (!regKey)
+    return false;
+
+  nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                             fileExtToUse,
+                             nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+  if (NS_FAILED(rv))
+    return false;
+
+  nsAutoString mimeType;
+  if (NS_FAILED(regKey->ReadStringValue(NS_LITERAL_STRING("Content Type"),
+                mimeType)) || mimeType.IsEmpty()) {
+    return false;
+  }
+  // Content-Type is always in ASCII
+  aMIMEType.Truncate();
+  LossyAppendUTF16toASCII(mimeType, aMIMEType);
+  return true;
+}