Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

6 files changed, 1867 insertions, 0 deletions

diff --git a/uriloader/exthandler/unix/nsGNOMERegistry.cpp b/uriloader/exthandler/unix/nsGNOMERegistry.cpp
new file mode 100644
index 0000000000..ab2d4bc833
--- /dev/null
+++ b/uriloader/exthandler/unix/nsGNOMERegistry.cpp
@@ -0,0 +1,104 @@
+/* -*- 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 "mozilla/StaticPrefs_browser.h"
+#include "nsGNOMERegistry.h"
+#include "nsString.h"
+#include "nsMIMEInfoUnix.h"
+#include "nsIGIOService.h"
+
+/* static */
+bool nsGNOMERegistry::HandlerExists(const char* aProtocolScheme) {
+  nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
+  if (!giovfs) {
+    return false;
+  }
+
+  nsCOMPtr<nsIHandlerApp> app;
+  return NS_SUCCEEDED(giovfs->GetAppForURIScheme(
+      nsDependentCString(aProtocolScheme), getter_AddRefs(app)));
+}
+
+// XXX Check HandlerExists() before calling LoadURL.
+
+/* static */
+nsresult nsGNOMERegistry::LoadURL(nsIURI* aURL) {
+  nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
+  if (!giovfs) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return giovfs->ShowURI(aURL);
+}
+
+/* static */
+void nsGNOMERegistry::GetAppDescForScheme(const nsACString& aScheme,
+                                          nsAString& aDesc) {
+  nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
+  if (!giovfs) return;
+
+  nsCOMPtr<nsIHandlerApp> app;
+  if (NS_FAILED(giovfs->GetAppForURIScheme(aScheme, getter_AddRefs(app))))
+    return;
+
+  app->GetName(aDesc);
+}
+
+/* static */
+already_AddRefed<nsMIMEInfoBase> nsGNOMERegistry::GetFromExtension(
+    const nsACString& aFileExt) {
+  nsAutoCString mimeType;
+  nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
+  if (!giovfs) {
+    return nullptr;
+  }
+
+  // Get the MIME type from the extension, then call GetFromType to
+  // fill in the MIMEInfo.
+  if (NS_FAILED(giovfs->GetMimeTypeFromExtension(aFileExt, mimeType)) ||
+      mimeType.EqualsLiteral("application/octet-stream")) {
+    return nullptr;
+  }
+
+  RefPtr<nsMIMEInfoBase> mi = GetFromType(mimeType);
+  if (mi) {
+    mi->AppendExtension(aFileExt);
+  }
+
+  return mi.forget();
+}
+
+/* static */
+already_AddRefed<nsMIMEInfoBase> nsGNOMERegistry::GetFromType(
+    const nsACString& aMIMEType) {
+  RefPtr<nsMIMEInfoUnix> mimeInfo = new nsMIMEInfoUnix(aMIMEType);
+  NS_ENSURE_TRUE(mimeInfo, nullptr);
+
+  nsAutoString name;
+  nsAutoCString description;
+
+  nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
+  if (!giovfs) {
+    return nullptr;
+  }
+
+  nsCOMPtr<nsIHandlerApp> handlerApp;
+  if (NS_FAILED(
+          giovfs->GetAppForMimeType(aMIMEType, getter_AddRefs(handlerApp))) ||
+      !handlerApp) {
+    return nullptr;
+  }
+  handlerApp->GetName(name);
+  giovfs->GetDescriptionForMimeType(aMIMEType, description);
+
+  mimeInfo->SetDefaultDescription(name);
+
+  mozilla::StaticPrefs::browser_download_improvements_to_download_panel()
+      ? mimeInfo->SetPreferredAction(nsIMIMEInfo::saveToDisk)
+      : mimeInfo->SetPreferredAction(nsIMIMEInfo::useSystemDefault);
+  mimeInfo->SetDescription(NS_ConvertUTF8toUTF16(description));
+
+  return mimeInfo.forget();
+}
diff --git a/uriloader/exthandler/unix/nsGNOMERegistry.h b/uriloader/exthandler/unix/nsGNOMERegistry.h
new file mode 100644
index 0000000000..ea626c5b50
--- /dev/null
+++ b/uriloader/exthandler/unix/nsGNOMERegistry.h
@@ -0,0 +1,28 @@
+/* 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/. */
+
+#ifndef nsGNOMERegistry_h
+#define nsGNOMERegistry_h
+
+#include "nsIURI.h"
+#include "nsCOMPtr.h"
+
+class nsMIMEInfoBase;
+
+class nsGNOMERegistry {
+ public:
+  static bool HandlerExists(const char* aProtocolScheme);
+
+  static nsresult LoadURL(nsIURI* aURL);
+
+  static void GetAppDescForScheme(const nsACString& aScheme, nsAString& aDesc);
+
+  static already_AddRefed<nsMIMEInfoBase> GetFromExtension(
+      const nsACString& aFileExt);
+
+  static already_AddRefed<nsMIMEInfoBase> GetFromType(
+      const nsACString& aMIMEType);
+};
+
+#endif  // nsGNOMERegistry_h
diff --git a/uriloader/exthandler/unix/nsMIMEInfoUnix.cpp b/uriloader/exthandler/unix/nsMIMEInfoUnix.cpp
new file mode 100644
index 0000000000..7cbefcce3e
--- /dev/null
+++ b/uriloader/exthandler/unix/nsMIMEInfoUnix.cpp
@@ -0,0 +1,80 @@
+/* -*- Mode: C++; tab-width: 3; 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 "nsMIMEInfoUnix.h"
+#include "nsGNOMERegistry.h"
+#include "nsIGIOService.h"
+#include "nsNetCID.h"
+#include "nsIIOService.h"
+#ifdef MOZ_ENABLE_DBUS
+#  include "nsDBusHandlerApp.h"
+#endif
+
+nsresult nsMIMEInfoUnix::LoadUriInternal(nsIURI* aURI) {
+  return nsGNOMERegistry::LoadURL(aURI);
+}
+
+NS_IMETHODIMP
+nsMIMEInfoUnix::GetHasDefaultHandler(bool* _retval) {
+  // if mDefaultApplication is set, it means the application has been set from
+  // either /etc/mailcap or ${HOME}/.mailcap, in which case we don't want to
+  // give the GNOME answer.
+  if (mDefaultApplication) return nsMIMEInfoImpl::GetHasDefaultHandler(_retval);
+
+  *_retval = false;
+
+  if (mClass == eProtocolInfo) {
+    *_retval = nsGNOMERegistry::HandlerExists(mSchemeOrType.get());
+  } else {
+    RefPtr<nsMIMEInfoBase> mimeInfo =
+        nsGNOMERegistry::GetFromType(mSchemeOrType);
+    if (!mimeInfo) {
+      nsAutoCString ext;
+      nsresult rv = GetPrimaryExtension(ext);
+      if (NS_SUCCEEDED(rv)) {
+        mimeInfo = nsGNOMERegistry::GetFromExtension(ext);
+      }
+    }
+    if (mimeInfo) *_retval = true;
+  }
+
+  if (*_retval) return NS_OK;
+
+  return NS_OK;
+}
+
+nsresult nsMIMEInfoUnix::LaunchDefaultWithFile(nsIFile* aFile) {
+  // if mDefaultApplication is set, it means the application has been set from
+  // either /etc/mailcap or ${HOME}/.mailcap, in which case we don't want to
+  // give the GNOME answer.
+  if (mDefaultApplication) return nsMIMEInfoImpl::LaunchDefaultWithFile(aFile);
+
+  nsAutoCString nativePath;
+  aFile->GetNativePath(nativePath);
+
+  nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
+  if (!giovfs) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // nsGIOMimeApp->Launch wants a URI string instead of local file
+  nsresult rv;
+  nsCOMPtr<nsIIOService> ioservice =
+      do_GetService(NS_IOSERVICE_CONTRACTID, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIURI> uri;
+  rv = ioservice->NewFileURI(aFile, getter_AddRefs(uri));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIHandlerApp> app;
+  if (NS_FAILED(
+          giovfs->GetAppForMimeType(mSchemeOrType, getter_AddRefs(app))) ||
+      !app) {
+    return NS_ERROR_FILE_NOT_FOUND;
+  }
+
+  return app->LaunchWithURI(uri, nullptr);
+}
diff --git a/uriloader/exthandler/unix/nsMIMEInfoUnix.h b/uriloader/exthandler/unix/nsMIMEInfoUnix.h
new file mode 100644
index 0000000000..2e32be4915
--- /dev/null
+++ b/uriloader/exthandler/unix/nsMIMEInfoUnix.h
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 3; 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/. */
+
+#ifndef nsMIMEInfoUnix_h_
+#define nsMIMEInfoUnix_h_
+
+#include "nsMIMEInfoImpl.h"
+
+class nsMIMEInfoUnix : public nsMIMEInfoImpl {
+ public:
+  explicit nsMIMEInfoUnix(const char* aMIMEType = "")
+      : nsMIMEInfoImpl(aMIMEType) {}
+  explicit nsMIMEInfoUnix(const nsACString& aMIMEType)
+      : nsMIMEInfoImpl(aMIMEType) {}
+  nsMIMEInfoUnix(const nsACString& aType, HandlerClass aClass)
+      : nsMIMEInfoImpl(aType, aClass) {}
+  static bool HandlerExists(const char* aProtocolScheme);
+
+ protected:
+  NS_IMETHOD GetHasDefaultHandler(bool* _retval) override;
+
+  virtual nsresult LoadUriInternal(nsIURI* aURI) override;
+
+  virtual nsresult LaunchDefaultWithFile(nsIFile* aFile) override;
+};
+
+#endif  // nsMIMEInfoUnix_h_
diff --git a/uriloader/exthandler/unix/nsOSHelperAppService.cpp b/uriloader/exthandler/unix/nsOSHelperAppService.cpp
new file mode 100644
index 0000000000..8b5820b9fd
--- /dev/null
+++ b/uriloader/exthandler/unix/nsOSHelperAppService.cpp
@@ -0,0 +1,1503 @@
+/* -*- Mode: C++; tab-width: 3; 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 <sys/types.h>
+#include <sys/stat.h>
+
+#include "nsOSHelperAppService.h"
+#include "nsMIMEInfoUnix.h"
+#ifdef MOZ_WIDGET_GTK
+#  include "nsGNOMERegistry.h"
+#  ifdef MOZ_BUILD_APP_IS_BROWSER
+#    include "nsIToolkitShellService.h"
+#    include "nsIGNOMEShellService.h"
+#  endif
+#endif
+#include "nsISupports.h"
+#include "nsString.h"
+#include "nsReadableUtils.h"
+#include "nsUnicharUtils.h"
+#include "nsIFileStreams.h"
+#include "nsILineInputStream.h"
+#include "nsIFile.h"
+#include "nsIProcess.h"
+#include "nsNetCID.h"
+#include "nsXPCOM.h"
+#include "nsComponentManagerUtils.h"
+#include "nsCRT.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsXULAppAPI.h"
+#include "ContentHandlerService.h"
+#include "prenv.h"  // for PR_GetEnv()
+#include "mozilla/EnumeratedRange.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "nsMimeTypes.h"
+#include <mutex>
+
+using namespace mozilla;
+
+#define LOG(...) \
+  MOZ_LOG(nsOSHelperAppService::sLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#define LOG_ENABLED() \
+  MOZ_LOG_TEST(nsOSHelperAppService::sLog, mozilla::LogLevel::Debug)
+
+static nsresult FindSemicolon(nsAString::const_iterator& aSemicolon_iter,
+                              const nsAString::const_iterator& aEnd_iter);
+static nsresult ParseMIMEType(const nsAString::const_iterator& aStart_iter,
+                              nsAString::const_iterator& aMajorTypeStart,
+                              nsAString::const_iterator& aMajorTypeEnd,
+                              nsAString::const_iterator& aMinorTypeStart,
+                              nsAString::const_iterator& aMinorTypeEnd,
+                              const nsAString::const_iterator& aEnd_iter);
+
+inline bool IsNetscapeFormat(const nsACString& aBuffer);
+
+nsOSHelperAppService::~nsOSHelperAppService() {}
+
+/*
+ * Take a command with all the mailcap escapes in it and unescape it
+ * Ideally this needs the mime type, mime type options, and location of the
+ * temporary file, but this last can't be got from here
+ */
+// static
+nsresult nsOSHelperAppService::UnescapeCommand(const nsAString& aEscapedCommand,
+                                               const nsAString& aMajorType,
+                                               const nsAString& aMinorType,
+                                               nsACString& aUnEscapedCommand) {
+  LOG("-- UnescapeCommand");
+  LOG("Command to escape: '%s'\n",
+      NS_LossyConvertUTF16toASCII(aEscapedCommand).get());
+  //  XXX This function will need to get the mime type and various stuff like
+  //  that being passed in to work properly
+
+  LOG(
+      ("UnescapeCommand really needs some work -- it should actually do some "
+       "unescaping\n"));
+
+  CopyUTF16toUTF8(aEscapedCommand, aUnEscapedCommand);
+  LOG("Escaped command: '%s'\n", PromiseFlatCString(aUnEscapedCommand).get());
+  return NS_OK;
+}
+
+/* Put aSemicolon_iter at the first non-escaped semicolon after
+ * aStart_iter but before aEnd_iter
+ */
+
+static nsresult FindSemicolon(nsAString::const_iterator& aSemicolon_iter,
+                              const nsAString::const_iterator& aEnd_iter) {
+  bool semicolonFound = false;
+  while (aSemicolon_iter != aEnd_iter && !semicolonFound) {
+    switch (*aSemicolon_iter) {
+      case '\\':
+        aSemicolon_iter.advance(2);
+        break;
+      case ';':
+        semicolonFound = true;
+        break;
+      default:
+        ++aSemicolon_iter;
+        break;
+    }
+  }
+  return NS_OK;
+}
+
+static nsresult ParseMIMEType(const nsAString::const_iterator& aStart_iter,
+                              nsAString::const_iterator& aMajorTypeStart,
+                              nsAString::const_iterator& aMajorTypeEnd,
+                              nsAString::const_iterator& aMinorTypeStart,
+                              nsAString::const_iterator& aMinorTypeEnd,
+                              const nsAString::const_iterator& aEnd_iter) {
+  nsAString::const_iterator iter(aStart_iter);
+
+  // skip leading whitespace
+  while (iter != aEnd_iter && nsCRT::IsAsciiSpace(*iter)) {
+    ++iter;
+  }
+
+  if (iter == aEnd_iter) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  aMajorTypeStart = iter;
+
+  // find major/minor separator ('/')
+  while (iter != aEnd_iter && *iter != '/') {
+    ++iter;
+  }
+
+  if (iter == aEnd_iter) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  aMajorTypeEnd = iter;
+
+  // skip '/'
+  ++iter;
+
+  if (iter == aEnd_iter) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  aMinorTypeStart = iter;
+
+  // find end of minor type, delimited by whitespace or ';'
+  while (iter != aEnd_iter && !nsCRT::IsAsciiSpace(*iter) && *iter != ';') {
+    ++iter;
+  }
+
+  aMinorTypeEnd = iter;
+
+  return NS_OK;
+}
+
+// TODO: We should consider not only caching the file location but maybe the
+// file contents too?
+enum class FileKind {
+  PrivateMimeTypes = 0,
+  GlobalMimeTypes,
+  PrivateMailCap,
+  GlobalMailCap,
+
+  Count,
+};
+
+struct FileLocationCache {
+  struct Entry {
+    bool mIsCached = false;
+    nsresult mResult = NS_OK;
+    nsString mLocation;
+
+    void Clear() { *this = {}; }
+  };
+
+  EnumeratedArray<FileKind, FileKind::Count, Entry> mEntries;
+
+  static const char* PrefFor(FileKind aKind) {
+    switch (aKind) {
+      case FileKind::GlobalMimeTypes:
+        return "helpers.global_mime_types_file";
+      case FileKind::PrivateMimeTypes:
+        return "helpers.private_mime_types_file";
+      case FileKind::GlobalMailCap:
+        return "helpers.global_mailcap_file";
+      case FileKind::PrivateMailCap:
+        return "helpers.private_mailcap_file";
+      case FileKind::Count:
+        break;
+    }
+    MOZ_ASSERT_UNREACHABLE("Unknown file kind");
+    return "";
+  }
+
+  void Clear() {
+    for (auto& entry : mEntries) {
+      entry.Clear();
+    }
+  }
+
+  static void PrefChangeCallback(const char*, void*) { Get().Clear(); }
+
+  static FileLocationCache& Get() {
+    static FileLocationCache sCache;
+    static std::once_flag flag;
+    std::call_once(flag, [&] {
+      for (auto kind :
+           MakeEnumeratedRange(FileKind::PrivateMimeTypes, FileKind::Count)) {
+        Preferences::RegisterCallback(PrefChangeCallback,
+                                      nsDependentCString(PrefFor(kind)));
+      }
+      RunOnShutdown([] {
+        sCache.Clear();
+        for (auto kind :
+             MakeEnumeratedRange(FileKind::PrivateMimeTypes, FileKind::Count)) {
+          Preferences::UnregisterCallback(PrefChangeCallback,
+                                          nsDependentCString(PrefFor(kind)));
+        }
+      });
+    });
+    return sCache;
+  }
+
+  Entry& EntryFor(FileKind aKind) { return mEntries[aKind]; }
+};
+
+// The lookup order is:
+//    1) user pref
+//    2) env var (if any)
+//    3) pref
+static nsresult DoGetFileLocation(FileKind aKind, nsAString& aFileLocation) {
+  LOG("-- GetFileLocation(%d)\n", int(aKind));
+
+  aFileLocation.Truncate();
+
+  const char* envVar = [&]() -> const char* {
+    switch (aKind) {
+      case FileKind::PrivateMailCap:
+        return "PERSONAL_MAILCAP";
+      case FileKind::GlobalMailCap:
+        return "MAILCAP";
+      default:
+        return nullptr;
+    }
+  }();
+
+  const char* prefName = FileLocationCache::PrefFor(aKind);
+
+  if (envVar) {
+    // If we have an env var we should check whether the pref is a user pref. If
+    // we do not, we don't care.
+    if (Preferences::HasUserValue(prefName) &&
+        NS_SUCCEEDED(Preferences::GetString(prefName, aFileLocation))) {
+      return NS_OK;
+    }
+
+    char* envValue = PR_GetEnv(envVar);
+    if (envValue && *envValue) {
+      // the pref is in the system charset and it's a filepath... The
+      // natural way to do the charset conversion is by just initing
+      // an nsIFile with the native path and asking it for the Unicode
+      // version.
+      nsresult rv;
+      nsCOMPtr<nsIFile> file(do_CreateInstance(NS_LOCAL_FILE_CONTRACTID, &rv));
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      rv = file->InitWithNativePath(nsDependentCString(envValue));
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      return file->GetPath(aFileLocation);
+    }
+  }
+
+  return Preferences::GetString(prefName, aFileLocation);
+}
+
+static nsresult GetFileLocation(FileKind aKind, nsAString& aFileLocation) {
+  MOZ_ASSERT(NS_IsMainThread());
+  auto& entry = FileLocationCache::Get().EntryFor(aKind);
+  if (!entry.mIsCached) {
+    entry.mIsCached = true;
+    entry.mResult = DoGetFileLocation(aKind, entry.mLocation);
+  }
+  aFileLocation = entry.mLocation;
+  return entry.mResult;
+}
+
+/* Get the mime.types file names from prefs and look up info in them
+   based on extension */
+// static
+nsresult nsOSHelperAppService::LookUpTypeAndDescription(
+    const nsAString& aFileExtension, nsAString& aMajorType,
+    nsAString& aMinorType, nsAString& aDescription, bool aUserData) {
+  LOG("-- LookUpTypeAndDescription for extension '%s'\n",
+      NS_LossyConvertUTF16toASCII(aFileExtension).get());
+  nsAutoString mimeFileName;
+
+  auto kind =
+      aUserData ? FileKind::PrivateMimeTypes : FileKind::GlobalMimeTypes;
+  nsresult rv = GetFileLocation(kind, mimeFileName);
+  if (NS_SUCCEEDED(rv) && !mimeFileName.IsEmpty()) {
+    rv = GetTypeAndDescriptionFromMimetypesFile(
+        mimeFileName, aFileExtension, aMajorType, aMinorType, aDescription);
+  } else {
+    rv = NS_ERROR_NOT_AVAILABLE;
+  }
+
+  return rv;
+}
+
+inline bool IsNetscapeFormat(const nsACString& aBuffer) {
+  return StringBeginsWith(
+             aBuffer,
+             nsLiteralCString(
+                 "#--Netscape Communications Corporation MIME Information")) ||
+         StringBeginsWith(aBuffer, "#--MCOM MIME Information"_ns);
+}
+
+/*
+ * Create a file stream and line input stream for the filename.
+ * Leaves the first line of the file in aBuffer and sets the format to
+ *  true for netscape files and false for normail ones
+ */
+// static
+nsresult nsOSHelperAppService::CreateInputStream(
+    const nsAString& aFilename, nsIFileInputStream** aFileInputStream,
+    nsILineInputStream** aLineInputStream, nsACString& aBuffer,
+    bool* aNetscapeFormat, bool* aMore) {
+  LOG("-- CreateInputStream");
+  nsresult rv = NS_OK;
+
+  nsCOMPtr<nsIFile> file(do_CreateInstance(NS_LOCAL_FILE_CONTRACTID, &rv));
+  if (NS_FAILED(rv)) return rv;
+  rv = file->InitWithPath(aFilename);
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsIFileInputStream> fileStream(
+      do_CreateInstance(NS_LOCALFILEINPUTSTREAM_CONTRACTID, &rv));
+  if (NS_FAILED(rv)) return rv;
+  rv = fileStream->Init(file, -1, -1, false);
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsILineInputStream> lineStream(do_QueryInterface(fileStream, &rv));
+
+  if (NS_FAILED(rv)) {
+    LOG("Interface trouble in stream land!");
+    return rv;
+  }
+
+  rv = lineStream->ReadLine(aBuffer, aMore);
+  if (NS_FAILED(rv)) {
+    fileStream->Close();
+    return rv;
+  }
+
+  *aNetscapeFormat = IsNetscapeFormat(aBuffer);
+
+  *aFileInputStream = fileStream;
+  NS_ADDREF(*aFileInputStream);
+  *aLineInputStream = lineStream;
+  NS_ADDREF(*aLineInputStream);
+
+  return NS_OK;
+}
+
+/* Open the file, read the first line, decide what type of file it is,
+   then get info based on extension */
+// static
+nsresult nsOSHelperAppService::GetTypeAndDescriptionFromMimetypesFile(
+    const nsAString& aFilename, const nsAString& aFileExtension,
+    nsAString& aMajorType, nsAString& aMinorType, nsAString& aDescription) {
+  LOG("-- GetTypeAndDescriptionFromMimetypesFile\n");
+  LOG("Getting type and description from types file '%s'\n",
+      NS_LossyConvertUTF16toASCII(aFilename).get());
+  LOG("Using extension '%s'\n",
+      NS_LossyConvertUTF16toASCII(aFileExtension).get());
+  nsCOMPtr<nsIFileInputStream> mimeFile;
+  nsCOMPtr<nsILineInputStream> mimeTypes;
+  bool netscapeFormat;
+  nsAutoString buf;
+  nsAutoCString cBuf;
+  bool more = false;
+  nsresult rv = CreateInputStream(aFilename, getter_AddRefs(mimeFile),
+                                  getter_AddRefs(mimeTypes), cBuf,
+                                  &netscapeFormat, &more);
+
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  nsAutoString extensions;
+  nsAutoStringN<101> entry;
+  nsAString::const_iterator majorTypeStart, majorTypeEnd, minorTypeStart,
+      minorTypeEnd, descriptionStart, descriptionEnd;
+
+  do {
+    CopyASCIItoUTF16(cBuf, buf);
+    // read through, building up an entry.  If we finish an entry, check for
+    // a match and return out of the loop if we match
+
+    // skip comments and empty lines
+    if (!buf.IsEmpty() && buf.First() != '#') {
+      entry.Append(buf);
+      if (entry.Last() == '\\') {
+        entry.Truncate(entry.Length() - 1);
+        entry.Append(char16_t(
+            ' '));  // in case there is no trailing whitespace on this line
+      } else {      // we have a full entry
+        LOG("Current entry: '%s'\n", NS_LossyConvertUTF16toASCII(entry).get());
+        if (netscapeFormat) {
+          rv = ParseNetscapeMIMETypesEntry(
+              entry, majorTypeStart, majorTypeEnd, minorTypeStart, minorTypeEnd,
+              extensions, descriptionStart, descriptionEnd);
+          if (NS_FAILED(rv)) {
+            // We sometimes get things like RealPlayer appending
+            // "normal" entries to "Netscape" .mime.types files.  Try
+            // to handle that.  Bug 106381.
+            LOG("Bogus entry; trying 'normal' mode\n");
+            rv = ParseNormalMIMETypesEntry(
+                entry, majorTypeStart, majorTypeEnd, minorTypeStart,
+                minorTypeEnd, extensions, descriptionStart, descriptionEnd);
+          }
+        } else {
+          rv = ParseNormalMIMETypesEntry(
+              entry, majorTypeStart, majorTypeEnd, minorTypeStart, minorTypeEnd,
+              extensions, descriptionStart, descriptionEnd);
+          if (NS_FAILED(rv)) {
+            // We sometimes get things like StarOffice prepending
+            // "normal" entries to "Netscape" .mime.types files.  Try
+            // to handle that.  Bug 136670.
+            LOG("Bogus entry; trying 'Netscape' mode\n");
+            rv = ParseNetscapeMIMETypesEntry(
+                entry, majorTypeStart, majorTypeEnd, minorTypeStart,
+                minorTypeEnd, extensions, descriptionStart, descriptionEnd);
+          }
+        }
+
+        if (NS_SUCCEEDED(rv)) {  // entry parses
+          nsAString::const_iterator start, end;
+          extensions.BeginReading(start);
+          extensions.EndReading(end);
+          nsAString::const_iterator iter(start);
+
+          while (start != end) {
+            FindCharInReadable(',', iter, end);
+            if (Substring(start, iter)
+                    .Equals(aFileExtension,
+                            nsCaseInsensitiveStringComparator)) {
+              // it's a match.  Assign the type and description and run
+              aMajorType.Assign(Substring(majorTypeStart, majorTypeEnd));
+              aMinorType.Assign(Substring(minorTypeStart, minorTypeEnd));
+              aDescription.Assign(Substring(descriptionStart, descriptionEnd));
+              mimeFile->Close();
+              return NS_OK;
+            }
+            if (iter != end) {
+              ++iter;
+            }
+            start = iter;
+          }
+        } else {
+          LOG("Failed to parse entry: %s\n",
+              NS_LossyConvertUTF16toASCII(entry).get());
+        }
+        // truncate the entry for the next iteration
+        entry.Truncate();
+      }
+    }
+    if (!more) {
+      rv = NS_ERROR_NOT_AVAILABLE;
+      break;
+    }
+    // read the next line
+    rv = mimeTypes->ReadLine(cBuf, &more);
+  } while (NS_SUCCEEDED(rv));
+
+  mimeFile->Close();
+  return rv;
+}
+
+/* Get the mime.types file names from prefs and look up info in them
+   based on mimetype  */
+// static
+nsresult nsOSHelperAppService::LookUpExtensionsAndDescription(
+    const nsAString& aMajorType, const nsAString& aMinorType,
+    nsAString& aFileExtensions, nsAString& aDescription) {
+  LOG("-- LookUpExtensionsAndDescription for type '%s/%s'\n",
+      NS_LossyConvertUTF16toASCII(aMajorType).get(),
+      NS_LossyConvertUTF16toASCII(aMinorType).get());
+  nsAutoString mimeFileName;
+
+  nsresult rv = GetFileLocation(FileKind::PrivateMimeTypes, mimeFileName);
+  if (NS_SUCCEEDED(rv) && !mimeFileName.IsEmpty()) {
+    rv = GetExtensionsAndDescriptionFromMimetypesFile(
+        mimeFileName, aMajorType, aMinorType, aFileExtensions, aDescription);
+  } else {
+    rv = NS_ERROR_NOT_AVAILABLE;
+  }
+  if (NS_FAILED(rv) || aFileExtensions.IsEmpty()) {
+    rv = GetFileLocation(FileKind::GlobalMimeTypes, mimeFileName);
+    if (NS_SUCCEEDED(rv) && !mimeFileName.IsEmpty()) {
+      rv = GetExtensionsAndDescriptionFromMimetypesFile(
+          mimeFileName, aMajorType, aMinorType, aFileExtensions, aDescription);
+    } else {
+      rv = NS_ERROR_NOT_AVAILABLE;
+    }
+  }
+  return rv;
+}
+
+/* Open the file, read the first line, decide what type of file it is,
+   then get info based on extension */
+// static
+nsresult nsOSHelperAppService::GetExtensionsAndDescriptionFromMimetypesFile(
+    const nsAString& aFilename, const nsAString& aMajorType,
+    const nsAString& aMinorType, nsAString& aFileExtensions,
+    nsAString& aDescription) {
+  LOG("-- GetExtensionsAndDescriptionFromMimetypesFile\n");
+  LOG("Getting extensions and description from types file '%s'\n",
+      NS_LossyConvertUTF16toASCII(aFilename).get());
+  LOG("Using type '%s/%s'\n", NS_LossyConvertUTF16toASCII(aMajorType).get(),
+      NS_LossyConvertUTF16toASCII(aMinorType).get());
+  nsCOMPtr<nsIFileInputStream> mimeFile;
+  nsCOMPtr<nsILineInputStream> mimeTypes;
+  bool netscapeFormat;
+  nsAutoCString cBuf;
+  nsAutoString buf;
+  bool more = false;
+  nsresult rv = CreateInputStream(aFilename, getter_AddRefs(mimeFile),
+                                  getter_AddRefs(mimeTypes), cBuf,
+                                  &netscapeFormat, &more);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  nsAutoString extensions;
+  nsAutoStringN<101> entry;
+  nsAString::const_iterator majorTypeStart, majorTypeEnd, minorTypeStart,
+      minorTypeEnd, descriptionStart, descriptionEnd;
+
+  do {
+    CopyASCIItoUTF16(cBuf, buf);
+    // read through, building up an entry.  If we finish an entry, check for
+    // a match and return out of the loop if we match
+
+    // skip comments and empty lines
+    if (!buf.IsEmpty() && buf.First() != '#') {
+      entry.Append(buf);
+      if (entry.Last() == '\\') {
+        entry.Truncate(entry.Length() - 1);
+        entry.Append(char16_t(
+            ' '));  // in case there is no trailing whitespace on this line
+      } else {      // we have a full entry
+        LOG("Current entry: '%s'\n", NS_LossyConvertUTF16toASCII(entry).get());
+        if (netscapeFormat) {
+          rv = ParseNetscapeMIMETypesEntry(
+              entry, majorTypeStart, majorTypeEnd, minorTypeStart, minorTypeEnd,
+              extensions, descriptionStart, descriptionEnd);
+
+          if (NS_FAILED(rv)) {
+            // We sometimes get things like RealPlayer appending
+            // "normal" entries to "Netscape" .mime.types files.  Try
+            // to handle that.  Bug 106381.
+            LOG("Bogus entry; trying 'normal' mode\n");
+            rv = ParseNormalMIMETypesEntry(
+                entry, majorTypeStart, majorTypeEnd, minorTypeStart,
+                minorTypeEnd, extensions, descriptionStart, descriptionEnd);
+          }
+        } else {
+          rv = ParseNormalMIMETypesEntry(
+              entry, majorTypeStart, majorTypeEnd, minorTypeStart, minorTypeEnd,
+              extensions, descriptionStart, descriptionEnd);
+
+          if (NS_FAILED(rv)) {
+            // We sometimes get things like StarOffice prepending
+            // "normal" entries to "Netscape" .mime.types files.  Try
+            // to handle that.  Bug 136670.
+            LOG("Bogus entry; trying 'Netscape' mode\n");
+            rv = ParseNetscapeMIMETypesEntry(
+                entry, majorTypeStart, majorTypeEnd, minorTypeStart,
+                minorTypeEnd, extensions, descriptionStart, descriptionEnd);
+          }
+        }
+
+        if (NS_SUCCEEDED(rv) &&
+            Substring(majorTypeStart, majorTypeEnd)
+                .Equals(aMajorType, nsCaseInsensitiveStringComparator) &&
+            Substring(minorTypeStart, minorTypeEnd)
+                .Equals(aMinorType, nsCaseInsensitiveStringComparator)) {
+          // it's a match
+          aFileExtensions.Assign(extensions);
+          aDescription.Assign(Substring(descriptionStart, descriptionEnd));
+          mimeFile->Close();
+          return NS_OK;
+        }
+        if (NS_FAILED(rv)) {
+          LOG("Failed to parse entry: %s\n",
+              NS_LossyConvertUTF16toASCII(entry).get());
+        }
+
+        entry.Truncate();
+      }
+    }
+    if (!more) {
+      rv = NS_ERROR_NOT_AVAILABLE;
+      break;
+    }
+    // read the next line
+    rv = mimeTypes->ReadLine(cBuf, &more);
+  } while (NS_SUCCEEDED(rv));
+
+  mimeFile->Close();
+  return rv;
+}
+
+/*
+ * This parses a Netscape format mime.types entry.  There are two
+ * possible formats:
+ *
+ * type=foo/bar; options exts="baz" description="Some type"
+ *
+ * and
+ *
+ * type=foo/bar; options description="Some type" exts="baz"
+ */
+// static
+nsresult nsOSHelperAppService::ParseNetscapeMIMETypesEntry(
+    const nsAString& aEntry, nsAString::const_iterator& aMajorTypeStart,
+    nsAString::const_iterator& aMajorTypeEnd,
+    nsAString::const_iterator& aMinorTypeStart,
+    nsAString::const_iterator& aMinorTypeEnd, nsAString& aExtensions,
+    nsAString::const_iterator& aDescriptionStart,
+    nsAString::const_iterator& aDescriptionEnd) {
+  LOG("-- ParseNetscapeMIMETypesEntry\n");
+  NS_ASSERTION(!aEntry.IsEmpty(),
+               "Empty Netscape MIME types entry being parsed.");
+
+  nsAString::const_iterator start_iter, end_iter, match_start, match_end;
+
+  aEntry.BeginReading(start_iter);
+  aEntry.EndReading(end_iter);
+
+  // skip trailing whitespace
+  do {
+    --end_iter;
+  } while (end_iter != start_iter && nsCRT::IsAsciiSpace(*end_iter));
+  // if we're pointing to a quote, don't advance -- we don't want to
+  // include the quote....
+  if (*end_iter != '"') ++end_iter;
+  match_start = start_iter;
+  match_end = end_iter;
+
+  // Get the major and minor types
+  // First the major type
+  if (!FindInReadable(u"type="_ns, match_start, match_end)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  match_start = match_end;
+
+  while (match_end != end_iter && *match_end != '/') {
+    ++match_end;
+  }
+  if (match_end == end_iter) {
+    return NS_ERROR_FAILURE;
+  }
+
+  aMajorTypeStart = match_start;
+  aMajorTypeEnd = match_end;
+
+  // now the minor type
+  if (++match_end == end_iter) {
+    return NS_ERROR_FAILURE;
+  }
+
+  match_start = match_end;
+
+  while (match_end != end_iter && !nsCRT::IsAsciiSpace(*match_end) &&
+         *match_end != ';') {
+    ++match_end;
+  }
+  if (match_end == end_iter) {
+    return NS_ERROR_FAILURE;
+  }
+
+  aMinorTypeStart = match_start;
+  aMinorTypeEnd = match_end;
+
+  // ignore everything up to the end of the mime type from here on
+  start_iter = match_end;
+
+  // get the extensions
+  match_start = match_end;
+  match_end = end_iter;
+  if (FindInReadable(u"exts="_ns, match_start, match_end)) {
+    nsAString::const_iterator extStart, extEnd;
+
+    if (match_end == end_iter ||
+        (*match_end == '"' && ++match_end == end_iter)) {
+      return NS_ERROR_FAILURE;
+    }
+
+    extStart = match_end;
+    match_start = extStart;
+    match_end = end_iter;
+    if (FindInReadable(u"desc=\""_ns, match_start, match_end)) {
+      // exts= before desc=, so we have to find the actual end of the extensions
+      extEnd = match_start;
+      if (extEnd == extStart) {
+        return NS_ERROR_FAILURE;
+      }
+
+      do {
+        --extEnd;
+      } while (extEnd != extStart && nsCRT::IsAsciiSpace(*extEnd));
+
+      if (extEnd != extStart && *extEnd == '"') {
+        --extEnd;
+      }
+    } else {
+      // desc= before exts=, so we can use end_iter as the end of the extensions
+      extEnd = end_iter;
+    }
+    aExtensions = Substring(extStart, extEnd);
+  } else {
+    // no extensions
+    aExtensions.Truncate();
+  }
+
+  // get the description
+  match_start = start_iter;
+  match_end = end_iter;
+  if (FindInReadable(u"desc=\""_ns, match_start, match_end)) {
+    aDescriptionStart = match_end;
+    match_start = aDescriptionStart;
+    match_end = end_iter;
+    if (FindInReadable(u"exts="_ns, match_start, match_end)) {
+      // exts= after desc=, so have to find actual end of description
+      aDescriptionEnd = match_start;
+      if (aDescriptionEnd == aDescriptionStart) {
+        return NS_ERROR_FAILURE;
+      }
+
+      do {
+        --aDescriptionEnd;
+      } while (aDescriptionEnd != aDescriptionStart &&
+               nsCRT::IsAsciiSpace(*aDescriptionEnd));
+    } else {
+      // desc= after exts=, so use end_iter for the description end
+      aDescriptionEnd = end_iter;
+    }
+  } else {
+    // no description
+    aDescriptionStart = start_iter;
+    aDescriptionEnd = start_iter;
+  }
+
+  return NS_OK;
+}
+
+/*
+ * This parses a normal format mime.types entry.  The format is:
+ *
+ * major/minor    ext1 ext2 ext3
+ */
+// static
+nsresult nsOSHelperAppService::ParseNormalMIMETypesEntry(
+    const nsAString& aEntry, nsAString::const_iterator& aMajorTypeStart,
+    nsAString::const_iterator& aMajorTypeEnd,
+    nsAString::const_iterator& aMinorTypeStart,
+    nsAString::const_iterator& aMinorTypeEnd, nsAString& aExtensions,
+    nsAString::const_iterator& aDescriptionStart,
+    nsAString::const_iterator& aDescriptionEnd) {
+  LOG("-- ParseNormalMIMETypesEntry\n");
+  NS_ASSERTION(!aEntry.IsEmpty(),
+               "Empty Normal MIME types entry being parsed.");
+
+  nsAString::const_iterator start_iter, end_iter, iter;
+
+  aEntry.BeginReading(start_iter);
+  aEntry.EndReading(end_iter);
+
+  // no description
+  aDescriptionStart = start_iter;
+  aDescriptionEnd = start_iter;
+
+  // skip leading whitespace
+  while (start_iter != end_iter && nsCRT::IsAsciiSpace(*start_iter)) {
+    ++start_iter;
+  }
+  if (start_iter == end_iter) {
+    return NS_ERROR_FAILURE;
+  }
+  // skip trailing whitespace
+  do {
+    --end_iter;
+  } while (end_iter != start_iter && nsCRT::IsAsciiSpace(*end_iter));
+
+  ++end_iter;  // point to first whitespace char (or to end of string)
+  iter = start_iter;
+
+  // get the major type
+  if (!FindCharInReadable('/', iter, end_iter)) return NS_ERROR_FAILURE;
+
+  nsAString::const_iterator equals_sign_iter(start_iter);
+  if (FindCharInReadable('=', equals_sign_iter, iter))
+    return NS_ERROR_FAILURE;  // see bug 136670
+
+  aMajorTypeStart = start_iter;
+  aMajorTypeEnd = iter;
+
+  // get the minor type
+  if (++iter == end_iter) {
+    return NS_ERROR_FAILURE;
+  }
+  start_iter = iter;
+
+  while (iter != end_iter && !nsCRT::IsAsciiSpace(*iter)) {
+    ++iter;
+  }
+  aMinorTypeStart = start_iter;
+  aMinorTypeEnd = iter;
+
+  // get the extensions
+  aExtensions.Truncate();
+  while (iter != end_iter) {
+    while (iter != end_iter && nsCRT::IsAsciiSpace(*iter)) {
+      ++iter;
+    }
+
+    start_iter = iter;
+    while (iter != end_iter && !nsCRT::IsAsciiSpace(*iter)) {
+      ++iter;
+    }
+    aExtensions.Append(Substring(start_iter, iter));
+    if (iter != end_iter) {  // not the last extension
+      aExtensions.Append(char16_t(','));
+    }
+  }
+
+  return NS_OK;
+}
+
+// static
+nsresult nsOSHelperAppService::LookUpHandlerAndDescription(
+    const nsAString& aMajorType, const nsAString& aMinorType,
+    nsAString& aHandler, nsAString& aDescription, nsAString& aMozillaFlags) {
+  // The mailcap lookup is two-pass to handle the case of mailcap files
+  // that have something like:
+  //
+  // text/*; emacs %s
+  // text/rtf; soffice %s
+  //
+  // in that order.  We want to pick up "soffice" for text/rtf in such cases
+  nsresult rv = DoLookUpHandlerAndDescription(
+      aMajorType, aMinorType, aHandler, aDescription, aMozillaFlags, true);
+  if (NS_FAILED(rv)) {
+    rv = DoLookUpHandlerAndDescription(aMajorType, aMinorType, aHandler,
+                                       aDescription, aMozillaFlags, false);
+  }
+
+  // maybe we have an entry for "aMajorType/*"?
+  if (NS_FAILED(rv)) {
+    rv = DoLookUpHandlerAndDescription(aMajorType, u"*"_ns, aHandler,
+                                       aDescription, aMozillaFlags, true);
+  }
+
+  if (NS_FAILED(rv)) {
+    rv = DoLookUpHandlerAndDescription(aMajorType, u"*"_ns, aHandler,
+                                       aDescription, aMozillaFlags, false);
+  }
+
+  return rv;
+}
+
+// static
+nsresult nsOSHelperAppService::DoLookUpHandlerAndDescription(
+    const nsAString& aMajorType, const nsAString& aMinorType,
+    nsAString& aHandler, nsAString& aDescription, nsAString& aMozillaFlags,
+    bool aUserData) {
+  LOG("-- LookUpHandlerAndDescription for type '%s/%s'\n",
+      NS_LossyConvertUTF16toASCII(aMajorType).get(),
+      NS_LossyConvertUTF16toASCII(aMinorType).get());
+  nsAutoString mailcapFileName;
+
+  const auto kind =
+      aUserData ? FileKind::PrivateMailCap : FileKind::GlobalMailCap;
+  nsresult rv = GetFileLocation(kind, mailcapFileName);
+  if (NS_FAILED(rv) || mailcapFileName.IsEmpty()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+  return GetHandlerAndDescriptionFromMailcapFile(mailcapFileName, aMajorType,
+                                                 aMinorType, aHandler,
+                                                 aDescription, aMozillaFlags);
+}
+
+// static
+nsresult nsOSHelperAppService::GetHandlerAndDescriptionFromMailcapFile(
+    const nsAString& aFilename, const nsAString& aMajorType,
+    const nsAString& aMinorType, nsAString& aHandler, nsAString& aDescription,
+    nsAString& aMozillaFlags) {
+  LOG("-- GetHandlerAndDescriptionFromMailcapFile\n");
+  LOG("Getting handler and description from mailcap file '%s'\n",
+      NS_LossyConvertUTF16toASCII(aFilename).get());
+  LOG("Using type '%s/%s'\n", NS_LossyConvertUTF16toASCII(aMajorType).get(),
+      NS_LossyConvertUTF16toASCII(aMinorType).get());
+
+  nsresult rv = NS_OK;
+  bool more = false;
+
+  nsCOMPtr<nsIFile> file(do_CreateInstance(NS_LOCAL_FILE_CONTRACTID, &rv));
+  if (NS_FAILED(rv)) return rv;
+  rv = file->InitWithPath(aFilename);
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsIFileInputStream> mailcapFile(
+      do_CreateInstance(NS_LOCALFILEINPUTSTREAM_CONTRACTID, &rv));
+  if (NS_FAILED(rv)) return rv;
+  rv = mailcapFile->Init(file, -1, -1, false);
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsILineInputStream> mailcap(do_QueryInterface(mailcapFile, &rv));
+
+  if (NS_FAILED(rv)) {
+    LOG("Interface trouble in stream land!");
+    return rv;
+  }
+
+  nsAutoStringN<129> entry;
+  nsAutoStringN<81> buffer;
+  nsAutoCStringN<81> cBuffer;
+  rv = mailcap->ReadLine(cBuffer, &more);
+  if (NS_FAILED(rv)) {
+    mailcapFile->Close();
+    return rv;
+  }
+
+  do {  // return on end-of-file in the loop
+
+    CopyASCIItoUTF16(cBuffer, buffer);
+    if (!buffer.IsEmpty() && buffer.First() != '#') {
+      entry.Append(buffer);
+      if (entry.Last() == '\\') {  // entry continues on next line
+        entry.Truncate(entry.Length() - 1);
+        entry.Append(char16_t(
+            ' '));  // in case there is no trailing whitespace on this line
+      } else {      // we have a full entry in entry.  Check it for the type
+        LOG("Current entry: '%s'\n", NS_LossyConvertUTF16toASCII(entry).get());
+
+        nsAString::const_iterator semicolon_iter, start_iter, end_iter,
+            majorTypeStart, majorTypeEnd, minorTypeStart, minorTypeEnd;
+        entry.BeginReading(start_iter);
+        entry.EndReading(end_iter);
+        semicolon_iter = start_iter;
+        FindSemicolon(semicolon_iter, end_iter);
+        if (semicolon_iter !=
+            end_iter) {  // we have something resembling a valid entry
+          rv = ParseMIMEType(start_iter, majorTypeStart, majorTypeEnd,
+                             minorTypeStart, minorTypeEnd, semicolon_iter);
+          if (NS_SUCCEEDED(rv) &&
+              Substring(majorTypeStart, majorTypeEnd)
+                  .Equals(aMajorType, nsCaseInsensitiveStringComparator) &&
+              Substring(minorTypeStart, minorTypeEnd)
+                  .Equals(aMinorType, nsCaseInsensitiveStringComparator)) {
+            // we have a match
+            bool match = true;
+            ++semicolon_iter;  // point at the first char past the semicolon
+            start_iter = semicolon_iter;  // handler string starts here
+            FindSemicolon(semicolon_iter, end_iter);
+            while (start_iter != semicolon_iter &&
+                   nsCRT::IsAsciiSpace(*start_iter)) {
+              ++start_iter;
+            }
+
+            LOG("The real handler is: '%s'\n",
+                NS_LossyConvertUTF16toASCII(
+                    Substring(start_iter, semicolon_iter))
+                    .get());
+
+            // XXX ugly hack.  Just grab the executable name
+            nsAString::const_iterator end_handler_iter = semicolon_iter;
+            nsAString::const_iterator end_executable_iter = start_iter;
+            while (end_executable_iter != end_handler_iter &&
+                   !nsCRT::IsAsciiSpace(*end_executable_iter)) {
+              ++end_executable_iter;
+            }
+            // XXX End ugly hack
+
+            aHandler = Substring(start_iter, end_executable_iter);
+
+            nsAString::const_iterator start_option_iter, end_optionname_iter,
+                equal_sign_iter;
+            bool equalSignFound;
+            while (match && semicolon_iter != end_iter &&
+                   ++semicolon_iter !=
+                       end_iter) {  // there are options left and we still match
+              start_option_iter = semicolon_iter;
+              // skip over leading whitespace
+              while (start_option_iter != end_iter &&
+                     nsCRT::IsAsciiSpace(*start_option_iter)) {
+                ++start_option_iter;
+              }
+              if (start_option_iter == end_iter) {  // nothing actually here
+                break;
+              }
+              semicolon_iter = start_option_iter;
+              FindSemicolon(semicolon_iter, end_iter);
+              equal_sign_iter = start_option_iter;
+              equalSignFound = false;
+              while (equal_sign_iter != semicolon_iter && !equalSignFound) {
+                switch (*equal_sign_iter) {
+                  case '\\':
+                    equal_sign_iter.advance(2);
+                    break;
+                  case '=':
+                    equalSignFound = true;
+                    break;
+                  default:
+                    ++equal_sign_iter;
+                    break;
+                }
+              }
+              end_optionname_iter = start_option_iter;
+              // find end of option name
+              while (end_optionname_iter != equal_sign_iter &&
+                     !nsCRT::IsAsciiSpace(*end_optionname_iter)) {
+                ++end_optionname_iter;
+              }
+              nsDependentSubstring optionName(start_option_iter,
+                                              end_optionname_iter);
+              if (equalSignFound) {
+                // This is an option that has a name and value
+                if (optionName.EqualsLiteral("description")) {
+                  aDescription = Substring(++equal_sign_iter, semicolon_iter);
+                } else if (optionName.EqualsLiteral("x-mozilla-flags")) {
+                  aMozillaFlags = Substring(++equal_sign_iter, semicolon_iter);
+                } else if (optionName.EqualsLiteral("test")) {
+                  nsAutoCString testCommand;
+                  rv = UnescapeCommand(
+                      Substring(++equal_sign_iter, semicolon_iter), aMajorType,
+                      aMinorType, testCommand);
+                  if (NS_FAILED(rv)) continue;
+                  nsCOMPtr<nsIProcess> process =
+                      do_CreateInstance(NS_PROCESS_CONTRACTID, &rv);
+                  if (NS_FAILED(rv)) continue;
+                  nsCOMPtr<nsIFile> file(
+                      do_CreateInstance(NS_LOCAL_FILE_CONTRACTID, &rv));
+                  if (NS_FAILED(rv)) continue;
+                  rv = file->InitWithNativePath("/bin/sh"_ns);
+                  if (NS_FAILED(rv)) continue;
+                  rv = process->Init(file);
+                  if (NS_FAILED(rv)) continue;
+                  const char* args[] = {"-c", testCommand.get()};
+                  LOG("Running Test: %s\n", testCommand.get());
+                  rv = process->Run(true, args, 2);
+                  if (NS_FAILED(rv)) continue;
+                  int32_t exitValue;
+                  rv = process->GetExitValue(&exitValue);
+                  if (NS_FAILED(rv)) continue;
+                  LOG("Exit code: %d\n", exitValue);
+                  if (exitValue) {
+                    match = false;
+                  }
+                }
+              } else {
+                // This is an option that just has a name but no value (eg
+                // "copiousoutput")
+                if (optionName.EqualsLiteral("needsterminal")) {
+                  match = false;
+                }
+              }
+            }
+
+            if (match) {  // we did not fail any test clauses; all is good
+              // get out of here
+              mailcapFile->Close();
+              return NS_OK;
+            }
+            // pretend that this match never happened
+            aDescription.Truncate();
+            aMozillaFlags.Truncate();
+            aHandler.Truncate();
+          }
+        }
+        // zero out the entry for the next cycle
+        entry.Truncate();
+      }
+    }
+    if (!more) {
+      rv = NS_ERROR_NOT_AVAILABLE;
+      break;
+    }
+    rv = mailcap->ReadLine(cBuffer, &more);
+  } while (NS_SUCCEEDED(rv));
+  mailcapFile->Close();
+  return rv;
+}
+
+nsresult nsOSHelperAppService::OSProtocolHandlerExists(
+    const char* aProtocolScheme, bool* aHandlerExists) {
+  nsresult rv = NS_OK;
+
+  if (!XRE_IsContentProcess()) {
+#ifdef MOZ_WIDGET_GTK
+    // Check the GNOME registry for a protocol handler
+    *aHandlerExists = nsGNOMERegistry::HandlerExists(aProtocolScheme);
+#else
+    *aHandlerExists = false;
+#endif
+  } else {
+    *aHandlerExists = false;
+    nsCOMPtr<nsIHandlerService> handlerSvc =
+        do_GetService(NS_HANDLERSERVICE_CONTRACTID, &rv);
+    if (NS_SUCCEEDED(rv) && handlerSvc) {
+      rv = handlerSvc->ExistsForProtocolOS(nsCString(aProtocolScheme),
+                                           aHandlerExists);
+    }
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP nsOSHelperAppService::GetApplicationDescription(
+    const nsACString& aScheme, nsAString& _retval) {
+#ifdef MOZ_WIDGET_GTK
+  nsGNOMERegistry::GetAppDescForScheme(aScheme, _retval);
+  return _retval.IsEmpty() ? NS_ERROR_NOT_AVAILABLE : NS_OK;
+#else
+  return NS_ERROR_NOT_AVAILABLE;
+#endif
+}
+
+NS_IMETHODIMP nsOSHelperAppService::IsCurrentAppOSDefaultForProtocol(
+    const nsACString& aScheme, bool* _retval) {
+  *_retval = false;
+#if defined(MOZ_BUILD_APP_IS_BROWSER) && defined(MOZ_WIDGET_GTK)
+  if (nsCOMPtr<nsIGNOMEShellService> shell =
+          do_GetService(NS_TOOLKITSHELLSERVICE_CONTRACTID)) {
+    return shell->IsDefaultForScheme(aScheme, _retval);
+  }
+#endif
+  return NS_OK;
+}
+
+nsresult nsOSHelperAppService::GetFileTokenForPath(
+    const char16_t* platformAppPath, nsIFile** aFile) {
+  LOG("-- nsOSHelperAppService::GetFileTokenForPath: '%s'\n",
+      NS_LossyConvertUTF16toASCII(platformAppPath).get());
+  if (!*platformAppPath) {  // empty filename--return error
+    NS_WARNING("Empty filename passed in.");
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // first check if the base class implementation finds anything
+  nsresult rv =
+      nsExternalHelperAppService::GetFileTokenForPath(platformAppPath, aFile);
+  if (NS_SUCCEEDED(rv)) return rv;
+  // If the reason for failure was that the file doesn't exist, return too
+  // (because it means the path was absolute, and so that we shouldn't search in
+  // the path)
+  if (rv == NS_ERROR_FILE_NOT_FOUND) return rv;
+
+  // If we get here, we really should have a relative path.
+  NS_ASSERTION(*platformAppPath != char16_t('/'), "Unexpected absolute path");
+
+  nsCOMPtr<nsIFile> localFile(do_CreateInstance(NS_LOCAL_FILE_CONTRACTID));
+
+  if (!localFile) return NS_ERROR_NOT_INITIALIZED;
+
+  bool exists = false;
+  // ugly hack.  Walk the PATH variable...
+  char* unixpath = PR_GetEnv("PATH");
+  nsAutoCString path(unixpath);
+
+  const char* start_iter = path.BeginReading(start_iter);
+  const char* colon_iter = start_iter;
+  const char* end_iter = path.EndReading(end_iter);
+
+  while (start_iter != end_iter && !exists) {
+    while (colon_iter != end_iter && *colon_iter != ':') {
+      ++colon_iter;
+    }
+    localFile->InitWithNativePath(Substring(start_iter, colon_iter));
+    rv = localFile->AppendRelativePath(nsDependentString(platformAppPath));
+    // Failing AppendRelativePath is a bad thing - it should basically always
+    // succeed given a relative path. Show a warning if it does fail.
+    // To prevent infinite loops when it does fail, return at this point.
+    NS_ENSURE_SUCCESS(rv, rv);
+    localFile->Exists(&exists);
+    if (!exists) {
+      if (colon_iter == end_iter) {
+        break;
+      }
+      ++colon_iter;
+      start_iter = colon_iter;
+    }
+  }
+
+  if (exists) {
+    rv = NS_OK;
+  } else {
+    rv = NS_ERROR_NOT_AVAILABLE;
+  }
+
+  *aFile = localFile;
+  NS_IF_ADDREF(*aFile);
+
+  return rv;
+}
+
+already_AddRefed<nsMIMEInfoBase> nsOSHelperAppService::GetFromExtension(
+    const nsCString& aFileExt) {
+  // if the extension is empty, return immediately
+  if (aFileExt.IsEmpty()) {
+    return nullptr;
+  }
+
+  LOG("Here we do an extension lookup for '%s'\n", aFileExt.get());
+
+  nsAutoString majorType, minorType, mime_types_description,
+      mailcap_description, handler, mozillaFlags;
+
+  nsresult rv =
+      LookUpTypeAndDescription(NS_ConvertUTF8toUTF16(aFileExt), majorType,
+                               minorType, mime_types_description, true);
+
+  if (NS_FAILED(rv) || majorType.IsEmpty()) {
+#ifdef MOZ_WIDGET_GTK
+    LOG("Looking in GNOME registry\n");
+    RefPtr<nsMIMEInfoBase> gnomeInfo =
+        nsGNOMERegistry::GetFromExtension(aFileExt);
+    if (gnomeInfo) {
+      LOG("Got MIMEInfo from GNOME registry\n");
+      return gnomeInfo.forget();
+    }
+#endif
+
+    rv = LookUpTypeAndDescription(NS_ConvertUTF8toUTF16(aFileExt), majorType,
+                                  minorType, mime_types_description, false);
+  }
+
+  if (NS_FAILED(rv)) {
+    return nullptr;
+  }
+
+  NS_LossyConvertUTF16toASCII asciiMajorType(majorType);
+  NS_LossyConvertUTF16toASCII asciiMinorType(minorType);
+
+  LOG("Type/Description results:  majorType='%s', minorType='%s', "
+      "description='%s'\n",
+      asciiMajorType.get(), asciiMinorType.get(),
+      NS_LossyConvertUTF16toASCII(mime_types_description).get());
+
+  if (majorType.IsEmpty() && minorType.IsEmpty()) {
+    // we didn't get a type mapping, so we can't do anything useful
+    return nullptr;
+  }
+
+  nsAutoCString mimeType(asciiMajorType + "/"_ns + asciiMinorType);
+  RefPtr<nsMIMEInfoUnix> mimeInfo = new nsMIMEInfoUnix(mimeType);
+
+  mimeInfo->AppendExtension(aFileExt);
+  rv = LookUpHandlerAndDescription(majorType, minorType, handler,
+                                   mailcap_description, mozillaFlags);
+  LOG("Handler/Description results:  handler='%s', description='%s', "
+      "mozillaFlags='%s'\n",
+      NS_LossyConvertUTF16toASCII(handler).get(),
+      NS_LossyConvertUTF16toASCII(mailcap_description).get(),
+      NS_LossyConvertUTF16toASCII(mozillaFlags).get());
+  mailcap_description.Trim(" \t\"");
+  mozillaFlags.Trim(" \t");
+  if (!mime_types_description.IsEmpty()) {
+    mimeInfo->SetDescription(mime_types_description);
+  } else {
+    mimeInfo->SetDescription(mailcap_description);
+  }
+
+  if (NS_SUCCEEDED(rv) && handler.IsEmpty()) {
+    rv = NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (NS_SUCCEEDED(rv)) {
+    nsCOMPtr<nsIFile> handlerFile;
+    rv = GetFileTokenForPath(handler.get(), getter_AddRefs(handlerFile));
+
+    if (NS_SUCCEEDED(rv)) {
+      mimeInfo->SetDefaultApplication(handlerFile);
+      mozilla::StaticPrefs::browser_download_improvements_to_download_panel()
+          ? mimeInfo->SetPreferredAction(nsIMIMEInfo::saveToDisk)
+          : mimeInfo->SetPreferredAction(nsIMIMEInfo::useSystemDefault);
+      mimeInfo->SetDefaultDescription(handler);
+    }
+  }
+
+  if (NS_FAILED(rv)) {
+    mimeInfo->SetPreferredAction(nsIMIMEInfo::saveToDisk);
+  }
+
+  return mimeInfo.forget();
+}
+
+already_AddRefed<nsMIMEInfoBase> nsOSHelperAppService::GetFromType(
+    const nsCString& aMIMEType) {
+  // if the type is empty, return immediately
+  if (aMIMEType.IsEmpty()) {
+    return nullptr;
+  }
+
+  LOG("Here we do a mimetype lookup for '%s'\n", aMIMEType.get());
+
+  // extract the major and minor types
+  NS_ConvertASCIItoUTF16 mimeType(aMIMEType);
+  nsAString::const_iterator start_iter, end_iter, majorTypeStart, majorTypeEnd,
+      minorTypeStart, minorTypeEnd;
+
+  mimeType.BeginReading(start_iter);
+  mimeType.EndReading(end_iter);
+
+  // XXX FIXME: add typeOptions parsing in here
+  nsresult rv = ParseMIMEType(start_iter, majorTypeStart, majorTypeEnd,
+                              minorTypeStart, minorTypeEnd, end_iter);
+
+  if (NS_FAILED(rv)) {
+    return nullptr;
+  }
+
+  nsDependentSubstring majorType(majorTypeStart, majorTypeEnd);
+  nsDependentSubstring minorType(minorTypeStart, minorTypeEnd);
+
+  // First check the user's private mailcap file
+  nsAutoString mailcap_description, handler, mozillaFlags;
+  DoLookUpHandlerAndDescription(majorType, minorType, handler,
+                                mailcap_description, mozillaFlags, true);
+
+  LOG("Private Handler/Description results:  handler='%s', description='%s'\n",
+      NS_LossyConvertUTF16toASCII(handler).get(),
+      NS_LossyConvertUTF16toASCII(mailcap_description).get());
+
+  // Now look up our extensions
+  nsAutoString extensions, mime_types_description;
+  LookUpExtensionsAndDescription(majorType, minorType, extensions,
+                                 mime_types_description);
+
+#ifdef MOZ_WIDGET_GTK
+  if (handler.IsEmpty()) {
+    RefPtr<nsMIMEInfoBase> gnomeInfo = nsGNOMERegistry::GetFromType(aMIMEType);
+    if (gnomeInfo) {
+      LOG("Got MIMEInfo from GNOME registry without extensions; setting them "
+          "to %s\n",
+          NS_LossyConvertUTF16toASCII(extensions).get());
+
+      NS_ASSERTION(!gnomeInfo->HasExtensions(), "How'd that happen?");
+      gnomeInfo->SetFileExtensions(NS_ConvertUTF16toUTF8(extensions));
+      return gnomeInfo.forget();
+    }
+  }
+#endif
+
+  if (handler.IsEmpty()) {
+    DoLookUpHandlerAndDescription(majorType, minorType, handler,
+                                  mailcap_description, mozillaFlags, false);
+  }
+
+  if (handler.IsEmpty()) {
+    DoLookUpHandlerAndDescription(majorType, u"*"_ns, handler,
+                                  mailcap_description, mozillaFlags, true);
+  }
+
+  if (handler.IsEmpty()) {
+    DoLookUpHandlerAndDescription(majorType, u"*"_ns, handler,
+                                  mailcap_description, mozillaFlags, false);
+  }
+
+  LOG("Handler/Description results:  handler='%s', description='%s', "
+      "mozillaFlags='%s'\n",
+      NS_LossyConvertUTF16toASCII(handler).get(),
+      NS_LossyConvertUTF16toASCII(mailcap_description).get(),
+      NS_LossyConvertUTF16toASCII(mozillaFlags).get());
+
+  mailcap_description.Trim(" \t\"");
+  mozillaFlags.Trim(" \t");
+
+  if (handler.IsEmpty() && extensions.IsEmpty() &&
+      mailcap_description.IsEmpty() && mime_types_description.IsEmpty()) {
+    // No real useful info
+    return nullptr;
+  }
+
+  RefPtr<nsMIMEInfoUnix> mimeInfo = new nsMIMEInfoUnix(aMIMEType);
+
+  mimeInfo->SetFileExtensions(NS_ConvertUTF16toUTF8(extensions));
+  if (!mime_types_description.IsEmpty()) {
+    mimeInfo->SetDescription(mime_types_description);
+  } else {
+    mimeInfo->SetDescription(mailcap_description);
+  }
+
+  rv = NS_ERROR_NOT_AVAILABLE;
+  nsCOMPtr<nsIFile> handlerFile;
+  if (!handler.IsEmpty()) {
+    rv = GetFileTokenForPath(handler.get(), getter_AddRefs(handlerFile));
+  }
+
+  if (NS_SUCCEEDED(rv)) {
+    mimeInfo->SetDefaultApplication(handlerFile);
+    StaticPrefs::browser_download_improvements_to_download_panel()
+        ? mimeInfo->SetPreferredAction(nsIMIMEInfo::saveToDisk)
+        : mimeInfo->SetPreferredAction(nsIMIMEInfo::useSystemDefault);
+    mimeInfo->SetDefaultDescription(handler);
+  } else {
+    mimeInfo->SetPreferredAction(nsIMIMEInfo::saveToDisk);
+  }
+
+  return mimeInfo.forget();
+}
+
+nsresult nsOSHelperAppService::GetMIMEInfoFromOS(const nsACString& aType,
+                                                 const nsACString& aFileExt,
+                                                 bool* aFound,
+                                                 nsIMIMEInfo** aMIMEInfo) {
+  *aFound = true;
+  RefPtr<nsMIMEInfoBase> retval;
+  // Fallback to lookup by extension when generic 'application/octet-stream'
+  // content type is received.
+  if (!aType.EqualsLiteral(APPLICATION_OCTET_STREAM)) {
+    retval = GetFromType(PromiseFlatCString(aType));
+  }
+  bool hasDefault = false;
+  if (retval) retval->GetHasDefaultHandler(&hasDefault);
+  if (!retval || !hasDefault) {
+    RefPtr<nsMIMEInfoBase> miByExt =
+        GetFromExtension(PromiseFlatCString(aFileExt));
+    // If we had no extension match, but a type match, use that
+    if (!miByExt && retval) {
+      retval.forget(aMIMEInfo);
+      return NS_OK;
+    }
+    // If we had an extension match but no type match, set the mimetype and use
+    // it
+    if (!retval && miByExt) {
+      if (!aType.IsEmpty()) miByExt->SetMIMEType(aType);
+      miByExt.swap(retval);
+
+      retval.forget(aMIMEInfo);
+      return NS_OK;
+    }
+    // If we got nothing, make a new mimeinfo
+    if (!retval) {
+      *aFound = false;
+      retval = new nsMIMEInfoUnix(aType);
+      if (retval) {
+        if (!aFileExt.IsEmpty()) retval->AppendExtension(aFileExt);
+      }
+
+      retval.forget(aMIMEInfo);
+      return NS_OK;
+    }
+
+    // Copy the attributes of retval (mimeinfo from type) onto miByExt, to
+    // return it
+    // but reset to just collected mDefaultAppDescription (from ext)
+    nsAutoString byExtDefault;
+    miByExt->GetDefaultDescription(byExtDefault);
+    retval->SetDefaultDescription(byExtDefault);
+    retval->CopyBasicDataTo(miByExt);
+
+    miByExt.swap(retval);
+  }
+  retval.forget(aMIMEInfo);
+  return NS_OK;
+}
+
+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;
+
+  nsMIMEInfoUnix* handlerInfo =
+      new nsMIMEInfoUnix(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;
+}
diff --git a/uriloader/exthandler/unix/nsOSHelperAppService.h b/uriloader/exthandler/unix/nsOSHelperAppService.h
new file mode 100644
index 0000000000..25feeac359
--- /dev/null
+++ b/uriloader/exthandler/unix/nsOSHelperAppService.h
@@ -0,0 +1,122 @@
+/* -*- Mode: C++; tab-width: 3; 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/. */
+
+#ifndef nsOSHelperAppService_h__
+#define nsOSHelperAppService_h__
+
+// The OS helper app service is a subclass of nsExternalHelperAppService and is
+// implemented on each platform. It contains platform specific code for finding
+// helper applications for a given mime type in addition to launching those
+// applications.
+
+#include "nsExternalHelperAppService.h"
+#include "nsCExternalHandlerService.h"
+#include "nsCOMPtr.h"
+
+class nsIFileInputStream;
+class nsILineInputStream;
+class nsMIMEInfoBase;
+
+class nsOSHelperAppService : public nsExternalHelperAppService {
+ public:
+  virtual ~nsOSHelperAppService();
+
+  // method overrides for mime.types and mime.info look up steps
+  NS_IMETHOD GetMIMEInfoFromOS(const nsACString& aMimeType,
+                               const nsACString& aFileExt, bool* aFound,
+                               nsIMIMEInfo** aMIMEInfo) override;
+  NS_IMETHOD GetProtocolHandlerInfoFromOS(const nsACString& aScheme,
+                                          bool* found,
+                                          nsIHandlerInfo** _retval) override;
+
+  // override nsIExternalProtocolService methods
+  nsresult OSProtocolHandlerExists(const char* aProtocolScheme,
+                                   bool* aHandlerExists) override;
+  NS_IMETHOD GetApplicationDescription(const nsACString& aScheme,
+                                       nsAString& _retval) override;
+  NS_IMETHOD IsCurrentAppOSDefaultForProtocol(const nsACString& aScheme,
+                                              bool* _retval) override;
+
+  // GetFileTokenForPath must be implemented by each platform.
+  // platformAppPath --> a platform specific path to an application that we got
+  //                     out of the rdf data source. This can be a mac file
+  //                     spec, a unix path or a windows path depending on the
+  //                     platform
+  // aFile --> an nsIFile representation of that platform application path.
+  virtual nsresult GetFileTokenForPath(const char16_t* platformAppPath,
+                                       nsIFile** aFile) override;
+
+ protected:
+  already_AddRefed<nsMIMEInfoBase> GetFromType(const nsCString& aMimeType);
+  already_AddRefed<nsMIMEInfoBase> GetFromExtension(const nsCString& aFileExt);
+
+ private:
+  // Helper methods which have to access static members
+  static nsresult UnescapeCommand(const nsAString& aEscapedCommand,
+                                  const nsAString& aMajorType,
+                                  const nsAString& aMinorType,
+                                  nsACString& aUnEscapedCommand);
+  static nsresult LookUpTypeAndDescription(const nsAString& aFileExtension,
+                                           nsAString& aMajorType,
+                                           nsAString& aMinorType,
+                                           nsAString& aDescription,
+                                           bool aUserData);
+  static nsresult CreateInputStream(const nsAString& aFilename,
+                                    nsIFileInputStream** aFileInputStream,
+                                    nsILineInputStream** aLineInputStream,
+                                    nsACString& aBuffer, bool* aNetscapeFormat,
+                                    bool* aMore);
+
+  static nsresult GetTypeAndDescriptionFromMimetypesFile(
+      const nsAString& aFilename, const nsAString& aFileExtension,
+      nsAString& aMajorType, nsAString& aMinorType, nsAString& aDescription);
+
+  static nsresult LookUpExtensionsAndDescription(const nsAString& aMajorType,
+                                                 const nsAString& aMinorType,
+                                                 nsAString& aFileExtensions,
+                                                 nsAString& aDescription);
+
+  static nsresult GetExtensionsAndDescriptionFromMimetypesFile(
+      const nsAString& aFilename, const nsAString& aMajorType,
+      const nsAString& aMinorType, nsAString& aFileExtensions,
+      nsAString& aDescription);
+
+  static nsresult ParseNetscapeMIMETypesEntry(
+      const nsAString& aEntry, nsAString::const_iterator& aMajorTypeStart,
+      nsAString::const_iterator& aMajorTypeEnd,
+      nsAString::const_iterator& aMinorTypeStart,
+      nsAString::const_iterator& aMinorTypeEnd, nsAString& aExtensions,
+      nsAString::const_iterator& aDescriptionStart,
+      nsAString::const_iterator& aDescriptionEnd);
+
+  static nsresult ParseNormalMIMETypesEntry(
+      const nsAString& aEntry, nsAString::const_iterator& aMajorTypeStart,
+      nsAString::const_iterator& aMajorTypeEnd,
+      nsAString::const_iterator& aMinorTypeStart,
+      nsAString::const_iterator& aMinorTypeEnd, nsAString& aExtensions,
+      nsAString::const_iterator& aDescriptionStart,
+      nsAString::const_iterator& aDescriptionEnd);
+
+  static nsresult LookUpHandlerAndDescription(const nsAString& aMajorType,
+                                              const nsAString& aMinorType,
+                                              nsAString& aHandler,
+                                              nsAString& aDescription,
+                                              nsAString& aMozillaFlags);
+
+  static nsresult DoLookUpHandlerAndDescription(const nsAString& aMajorType,
+                                                const nsAString& aMinorType,
+                                                nsAString& aHandler,
+                                                nsAString& aDescription,
+                                                nsAString& aMozillaFlags,
+                                                bool aUserData);
+
+  static nsresult GetHandlerAndDescriptionFromMailcapFile(
+      const nsAString& aFilename, const nsAString& aMajorType,
+      const nsAString& aMinorType, nsAString& aHandler, nsAString& aDescription,
+      nsAString& aMozillaFlags);
+};
+
+#endif  // nsOSHelperAppService_h__