Adding upstream version 124.0.1.upstream/124.0.1

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

25 files changed, 7162 insertions, 0 deletions

diff --git a/netwerk/streamconv/converters/moz.build b/netwerk/streamconv/converters/moz.build
new file mode 100644
index 0000000000..d985eb363a
--- /dev/null
+++ b/netwerk/streamconv/converters/moz.build
@@ -0,0 +1,31 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+XPIDL_SOURCES += ["nsICompressConvStats.idl"]
+
+EXPORTS += [
+    "nsHTTPCompressConv.h",
+    "nsUnknownDecoder.h",
+]
+
+XPIDL_MODULE = "necko_http"
+
+UNIFIED_SOURCES += [
+    "mozTXTToHTMLConv.cpp",
+    "nsDirIndex.cpp",
+    "nsDirIndexParser.cpp",
+    "nsHTTPCompressConv.cpp",
+    "nsIndexedToHTML.cpp",
+    "nsMultiMixedConv.cpp",
+    "nsUnknownDecoder.cpp",
+]
+
+FINAL_LIBRARY = "xul"
+
+LOCAL_INCLUDES += [
+    "/modules/brotli/dec",
+    "/netwerk/base",
+]
diff --git a/netwerk/streamconv/converters/mozTXTToHTMLConv.cpp b/netwerk/streamconv/converters/mozTXTToHTMLConv.cpp
new file mode 100644
index 0000000000..a9f1d5183f
--- /dev/null
+++ b/netwerk/streamconv/converters/mozTXTToHTMLConv.cpp
@@ -0,0 +1,1291 @@
+/* -*- 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/TextUtils.h"
+#include "mozTXTToHTMLConv.h"
+#include "mozilla/intl/Segmenter.h"
+#include "mozilla/Maybe.h"
+#include "nsIThreadRetargetableStreamListener.h"
+#include "nsNetUtil.h"
+#include "nsUnicharUtils.h"
+#include "nsUnicodeProperties.h"
+#include "nsCRT.h"
+#include "nsIExternalProtocolHandler.h"
+#include "nsIURI.h"
+
+#include <algorithm>
+
+#ifdef DEBUG_BenB_Perf
+#  include "prtime.h"
+#  include "prinrval.h"
+#endif
+
+using mozilla::IsAscii;
+using mozilla::IsAsciiAlpha;
+using mozilla::IsAsciiDigit;
+using mozilla::Maybe;
+using mozilla::Some;
+using mozilla::Span;
+using mozilla::intl::GraphemeClusterBreakIteratorUtf16;
+using mozilla::intl::GraphemeClusterBreakReverseIteratorUtf16;
+
+const double growthRate = 1.2;
+
+// Bug 183111, editor now replaces multiple spaces with leading
+// 0xA0's and a single ending space, so need to treat 0xA0's as spaces.
+// 0xA0 is the Latin1/Unicode character for "non-breaking space (nbsp)"
+// Also recognize the Japanese ideographic space 0x3000 as a space.
+static inline bool IsSpace(const char16_t aChar) {
+  return (nsCRT::IsAsciiSpace(aChar) || aChar == 0xA0 || aChar == 0x3000);
+}
+
+// Escape Char will take ch, escape it and append the result to
+// aStringToAppendTo
+void mozTXTToHTMLConv::EscapeChar(const char16_t ch,
+                                  nsAString& aStringToAppendTo,
+                                  bool inAttribute) {
+  switch (ch) {
+    case '<':
+      aStringToAppendTo.AppendLiteral("&lt;");
+      break;
+    case '>':
+      aStringToAppendTo.AppendLiteral("&gt;");
+      break;
+    case '&':
+      aStringToAppendTo.AppendLiteral("&amp;");
+      break;
+    case '"':
+      if (inAttribute) {
+        aStringToAppendTo.AppendLiteral("&quot;");
+        break;
+      }
+      // else fall through
+      [[fallthrough]];
+    default:
+      aStringToAppendTo += ch;
+  }
+}
+
+// EscapeStr takes the passed in string and
+// escapes it IN PLACE.
+void mozTXTToHTMLConv::EscapeStr(nsString& aInString, bool inAttribute) {
+  // the replace substring routines
+  // don't seem to work if you have a character
+  // in the in string that is also in the replacement
+  // string! =(
+  // aInString.ReplaceSubstring("&", "&amp;");
+  // aInString.ReplaceSubstring("<", "&lt;");
+  // aInString.ReplaceSubstring(">", "&gt;");
+  for (uint32_t i = 0; i < aInString.Length();) {
+    switch (aInString[i]) {
+      case '<':
+        aInString.Cut(i, 1);
+        aInString.InsertLiteral(u"&lt;", i);
+        i += 4;  // skip past the integers we just added
+        break;
+      case '>':
+        aInString.Cut(i, 1);
+        aInString.InsertLiteral(u"&gt;", i);
+        i += 4;  // skip past the integers we just added
+        break;
+      case '&':
+        aInString.Cut(i, 1);
+        aInString.InsertLiteral(u"&amp;", i);
+        i += 5;  // skip past the integers we just added
+        break;
+      case '"':
+        if (inAttribute) {
+          aInString.Cut(i, 1);
+          aInString.InsertLiteral(u"&quot;", i);
+          i += 6;
+          break;
+        }
+        // else fall through
+        [[fallthrough]];
+      default:
+        i++;
+    }
+  }
+}
+
+void mozTXTToHTMLConv::UnescapeStr(const char16_t* aInString, int32_t aStartPos,
+                                   int32_t aLength, nsString& aOutString) {
+  const char16_t* subString = nullptr;
+  for (uint32_t i = aStartPos; int32_t(i) - aStartPos < aLength;) {
+    int32_t remainingChars = i - aStartPos;
+    if (aInString[i] == '&') {
+      subString = &aInString[i];
+      if (!NS_strncmp(subString, u"&lt;",
+                      std::min(4, aLength - remainingChars))) {
+        aOutString.Append(char16_t('<'));
+        i += 4;
+      } else if (!NS_strncmp(subString, u"&gt;",
+                             std::min(4, aLength - remainingChars))) {
+        aOutString.Append(char16_t('>'));
+        i += 4;
+      } else if (!NS_strncmp(subString, u"&amp;",
+                             std::min(5, aLength - remainingChars))) {
+        aOutString.Append(char16_t('&'));
+        i += 5;
+      } else if (!NS_strncmp(subString, u"&quot;",
+                             std::min(6, aLength - remainingChars))) {
+        aOutString.Append(char16_t('"'));
+        i += 6;
+      } else {
+        aOutString += aInString[i];
+        i++;
+      }
+    } else {
+      aOutString += aInString[i];
+      i++;
+    }
+  }
+}
+
+void mozTXTToHTMLConv::CompleteAbbreviatedURL(const char16_t* aInString,
+                                              int32_t aInLength,
+                                              const uint32_t pos,
+                                              nsString& aOutString) {
+  NS_ASSERTION(int32_t(pos) < aInLength,
+               "bad args to CompleteAbbreviatedURL, see bug #190851");
+  if (int32_t(pos) >= aInLength) return;
+
+  if (aInString[pos] == '@') {
+    // only pre-pend a mailto url if the string contains a .domain in it..
+    // i.e. we want to linkify johndoe@foo.com but not "let's meet @8pm"
+    nsDependentString inString(aInString, aInLength);
+    if (inString.FindChar('.', pos) !=
+        kNotFound)  // if we have a '.' after the @ sign....
+    {
+      aOutString.AssignLiteral("mailto:");
+      aOutString += aInString;
+    }
+  } else if (aInString[pos] == '.') {
+    if (ItMatchesDelimited(aInString, aInLength, u"www.", 4, LT_IGNORE,
+                           LT_IGNORE)) {
+      aOutString.AssignLiteral("http://");
+      aOutString += aInString;
+    }
+  }
+}
+
+bool mozTXTToHTMLConv::FindURLStart(const char16_t* aInString,
+                                    int32_t aInLength, const uint32_t pos,
+                                    const modetype check, uint32_t& start) {
+  switch (check) {  // no breaks, because end of blocks is never reached
+    case RFC1738: {
+      if (!NS_strncmp(&aInString[std::max(int32_t(pos - 4), 0)], u"<URL:", 5)) {
+        start = pos + 1;
+        return true;
+      }
+      return false;
+    }
+    case RFC2396E: {
+      nsDependentSubstring temp(aInString, aInLength);
+      int32_t i = pos <= 0 ? kNotFound : temp.RFindCharInSet(u"<>\"", pos - 1);
+      if (i != kNotFound &&
+          (temp[uint32_t(i)] == '<' || temp[uint32_t(i)] == '"')) {
+        start = uint32_t(++i);
+        return start < pos;
+      }
+      return false;
+    }
+    case freetext: {
+      int32_t i = pos - 1;
+      for (; i >= 0 &&
+             (IsAsciiAlpha(aInString[uint32_t(i)]) ||
+              IsAsciiDigit(aInString[uint32_t(i)]) ||
+              aInString[uint32_t(i)] == '+' || aInString[uint32_t(i)] == '-' ||
+              aInString[uint32_t(i)] == '.');
+           i--) {
+        ;
+      }
+      if (++i >= 0 && uint32_t(i) < pos &&
+          IsAsciiAlpha(aInString[uint32_t(i)])) {
+        start = uint32_t(i);
+        return true;
+      }
+      return false;
+    }
+    case abbreviated: {
+      int32_t i = pos - 1;
+      // This disallows non-ascii-characters for email.
+      // Currently correct, but revisit later after standards changed.
+      bool isEmail = aInString[pos] == (char16_t)'@';
+      // These chars mark the start of the URL
+      for (; i >= 0 && aInString[uint32_t(i)] != '>' &&
+             aInString[uint32_t(i)] != '<' && aInString[uint32_t(i)] != '"' &&
+             aInString[uint32_t(i)] != '\'' && aInString[uint32_t(i)] != '`' &&
+             aInString[uint32_t(i)] != ',' && aInString[uint32_t(i)] != '{' &&
+             aInString[uint32_t(i)] != '[' && aInString[uint32_t(i)] != '(' &&
+             aInString[uint32_t(i)] != '|' && aInString[uint32_t(i)] != '\\' &&
+             !IsSpace(aInString[uint32_t(i)]) &&
+             (!isEmail || IsAscii(aInString[uint32_t(i)])) &&
+             (!isEmail || aInString[uint32_t(i)] != ')');
+           i--) {
+        ;
+      }
+      if (++i >= 0 && uint32_t(i) < pos &&
+          (IsAsciiAlpha(aInString[uint32_t(i)]) ||
+           IsAsciiDigit(aInString[uint32_t(i)]))) {
+        start = uint32_t(i);
+        return true;
+      }
+      return false;
+    }
+    default:
+      return false;
+  }  // switch
+}
+
+bool mozTXTToHTMLConv::FindURLEnd(const char16_t* aInString,
+                                  int32_t aInStringLength, const uint32_t pos,
+                                  const modetype check, const uint32_t start,
+                                  uint32_t& end) {
+  switch (check) {  // no breaks, because end of blocks is never reached
+    case RFC1738:
+    case RFC2396E: {
+      nsDependentSubstring temp(aInString, aInStringLength);
+
+      int32_t i = temp.FindCharInSet(u"<>\"", pos + 1);
+      if (i != kNotFound &&
+          temp[uint32_t(i--)] ==
+              (check == RFC1738 || temp[start - 1] == '<' ? '>' : '"')) {
+        end = uint32_t(i);
+        return end > pos;
+      }
+      return false;
+    }
+    case freetext:
+    case abbreviated: {
+      uint32_t i = pos + 1;
+      bool isEmail = aInString[pos] == (char16_t)'@';
+      bool seenOpeningParenthesis = false;  // there is a '(' earlier in the URL
+      bool seenOpeningSquareBracket =
+          false;  // there is a '[' earlier in the URL
+      for (; int32_t(i) < aInStringLength; i++) {
+        // These chars mark the end of the URL
+        if (aInString[i] == '>' || aInString[i] == '<' || aInString[i] == '"' ||
+            aInString[i] == '`' || aInString[i] == '}' || aInString[i] == '{' ||
+            (aInString[i] == ')' && !seenOpeningParenthesis) ||
+            (aInString[i] == ']' && !seenOpeningSquareBracket) ||
+            // Allow IPv6 adresses like http://[1080::8:800:200C:417A]/foo.
+            (aInString[i] == '[' && i > 2 &&
+             (aInString[i - 1] != '/' || aInString[i - 2] != '/')) ||
+            IsSpace(aInString[i])) {
+          break;
+        }
+        // Disallow non-ascii-characters for email.
+        // Currently correct, but revisit later after standards changed.
+        if (isEmail && (aInString[i] == '(' || aInString[i] == '\'' ||
+                        !IsAscii(aInString[i]))) {
+          break;
+        }
+        if (aInString[i] == '(') seenOpeningParenthesis = true;
+        if (aInString[i] == '[') seenOpeningSquareBracket = true;
+      }
+      // These chars are allowed in the middle of the URL, but not at end.
+      // Technically they are, but are used in normal text after the URL.
+      while (--i > pos && (aInString[i] == '.' || aInString[i] == ',' ||
+                           aInString[i] == ';' || aInString[i] == '!' ||
+                           aInString[i] == '?' || aInString[i] == '-' ||
+                           aInString[i] == ':' || aInString[i] == '\'')) {
+        ;
+      }
+      if (i > pos) {
+        end = i;
+        return true;
+      }
+      return false;
+    }
+    default:
+      return false;
+  }  // switch
+}
+
+void mozTXTToHTMLConv::CalculateURLBoundaries(
+    const char16_t* aInString, int32_t aInStringLength, const uint32_t pos,
+    const uint32_t whathasbeendone, const modetype check, const uint32_t start,
+    const uint32_t end, nsString& txtURL, nsString& desc,
+    int32_t& replaceBefore, int32_t& replaceAfter) {
+  uint32_t descstart = start;
+  switch (check) {
+    case RFC1738: {
+      descstart = start - 5;
+      desc.Append(&aInString[descstart],
+                  end - descstart + 2);  // include "<URL:" and ">"
+      replaceAfter = end - pos + 1;
+    } break;
+    case RFC2396E: {
+      descstart = start - 1;
+      desc.Append(&aInString[descstart],
+                  end - descstart + 2);  // include brackets
+      replaceAfter = end - pos + 1;
+    } break;
+    case freetext:
+    case abbreviated: {
+      descstart = start;
+      desc.Append(&aInString[descstart],
+                  end - start + 1);  // don't include brackets
+      replaceAfter = end - pos;
+    } break;
+    default:
+      break;
+  }  // switch
+
+  EscapeStr(desc, false);
+
+  txtURL.Append(&aInString[start], end - start + 1);
+  txtURL.StripWhitespace();
+
+  // FIX ME
+  nsAutoString temp2;
+  ScanTXT(nsDependentSubstring(&aInString[descstart], pos - descstart),
+          ~kURLs /*prevents loop*/ & whathasbeendone, temp2);
+  replaceBefore = temp2.Length();
+}
+
+bool mozTXTToHTMLConv::ShouldLinkify(const nsCString& aURL) {
+  if (!mIOService) return false;
+
+  nsAutoCString scheme;
+  nsresult rv = mIOService->ExtractScheme(aURL, scheme);
+  if (NS_FAILED(rv)) return false;
+
+  if (scheme == "http" || scheme == "https" || scheme == "mailto") {
+    return true;
+  }
+
+  // Get the handler for this scheme.
+  nsCOMPtr<nsIProtocolHandler> handler;
+  rv = mIOService->GetProtocolHandler(scheme.get(), getter_AddRefs(handler));
+  if (NS_FAILED(rv)) return false;
+
+  // Is it an external protocol handler? If not, linkify it.
+  nsCOMPtr<nsIExternalProtocolHandler> externalHandler =
+      do_QueryInterface(handler);
+  if (!externalHandler) return true;  // handler is built-in, linkify it!
+
+  // If external app exists for the scheme then linkify it.
+  bool exists;
+  rv = externalHandler->ExternalAppExistsForScheme(scheme, &exists);
+  return (NS_SUCCEEDED(rv) && exists);
+}
+
+bool mozTXTToHTMLConv::CheckURLAndCreateHTML(const nsString& txtURL,
+                                             const nsString& desc,
+                                             const modetype mode,
+                                             nsString& outputHTML) {
+  // Create *uri from txtURL
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv;
+  // Lazily initialize mIOService
+  if (!mIOService) {
+    mIOService = do_GetIOService();
+
+    if (!mIOService) return false;
+  }
+
+  // See if the url should be linkified.
+  NS_ConvertUTF16toUTF8 utf8URL(txtURL);
+  if (!ShouldLinkify(utf8URL)) return false;
+
+  // it would be faster if we could just check to see if there is a protocol
+  // handler for the url and return instead of actually trying to create a
+  // url...
+  rv = mIOService->NewURI(utf8URL, nullptr, nullptr, getter_AddRefs(uri));
+
+  // Real work
+  if (NS_SUCCEEDED(rv) && uri) {
+    outputHTML.AssignLiteral("<a class=\"moz-txt-link-");
+    switch (mode) {
+      case RFC1738:
+        outputHTML.AppendLiteral("rfc1738");
+        break;
+      case RFC2396E:
+        outputHTML.AppendLiteral("rfc2396E");
+        break;
+      case freetext:
+        outputHTML.AppendLiteral("freetext");
+        break;
+      case abbreviated:
+        outputHTML.AppendLiteral("abbreviated");
+        break;
+      default:
+        break;
+    }
+    nsAutoString escapedURL(txtURL);
+    EscapeStr(escapedURL, true);
+
+    outputHTML.AppendLiteral("\" href=\"");
+    outputHTML += escapedURL;
+    outputHTML.AppendLiteral("\">");
+    outputHTML += desc;
+    outputHTML.AppendLiteral("</a>");
+    return true;
+  }
+  return false;
+}
+
+NS_IMETHODIMP mozTXTToHTMLConv::FindURLInPlaintext(const char16_t* aInString,
+                                                   int32_t aInLength,
+                                                   int32_t aPos,
+                                                   int32_t* aStartPos,
+                                                   int32_t* aEndPos) {
+  // call FindURL on the passed in string
+  nsAutoString outputHTML;  // we'll ignore the generated output HTML
+
+  *aStartPos = -1;
+  *aEndPos = -1;
+
+  FindURL(aInString, aInLength, aPos, kURLs, outputHTML, *aStartPos, *aEndPos);
+
+  return NS_OK;
+}
+
+bool mozTXTToHTMLConv::FindURL(const char16_t* aInString, int32_t aInLength,
+                               const uint32_t pos,
+                               const uint32_t whathasbeendone,
+                               nsString& outputHTML, int32_t& replaceBefore,
+                               int32_t& replaceAfter) {
+  enum statetype { unchecked, invalid, startok, endok, success };
+  static const modetype ranking[] = {RFC1738, RFC2396E, freetext, abbreviated};
+
+  statetype state[mozTXTToHTMLConv_lastMode + 1];  // 0(=unknown)..lastMode
+  /* I don't like this abuse of enums as index for the array,
+     but I don't know a better method */
+
+  // Define, which modes to check
+  /* all modes but abbreviated are checked for text[pos] == ':',
+     only abbreviated for '.', RFC2396E and abbreviated for '@' */
+  for (modetype iState = unknown; iState <= mozTXTToHTMLConv_lastMode;
+       iState = modetype(iState + 1)) {
+    state[iState] = aInString[pos] == ':' ? unchecked : invalid;
+  }
+  switch (aInString[pos]) {
+    case '@':
+      state[RFC2396E] = unchecked;
+      [[fallthrough]];
+    case '.':
+      state[abbreviated] = unchecked;
+      break;
+    case ':':
+      state[abbreviated] = invalid;
+      break;
+    default:
+      break;
+  }
+
+  // Test, first successful mode wins, sequence defined by |ranking|
+  int32_t iCheck = 0;  // the currently tested modetype
+  modetype check = ranking[iCheck];
+  for (; iCheck < mozTXTToHTMLConv_numberOfModes && state[check] != success;
+       iCheck++)
+  /* check state from last run.
+     If this is the first, check this one, which isn't = success yet */
+  {
+    check = ranking[iCheck];
+
+    uint32_t start, end;
+
+    if (state[check] == unchecked) {
+      if (FindURLStart(aInString, aInLength, pos, check, start)) {
+        state[check] = startok;
+      }
+    }
+
+    if (state[check] == startok) {
+      if (FindURLEnd(aInString, aInLength, pos, check, start, end)) {
+        state[check] = endok;
+      }
+    }
+
+    if (state[check] == endok) {
+      nsAutoString txtURL, desc;
+      int32_t resultReplaceBefore, resultReplaceAfter;
+
+      CalculateURLBoundaries(aInString, aInLength, pos, whathasbeendone, check,
+                             start, end, txtURL, desc, resultReplaceBefore,
+                             resultReplaceAfter);
+
+      if (aInString[pos] != ':') {
+        nsAutoString temp = txtURL;
+        txtURL.SetLength(0);
+        CompleteAbbreviatedURL(temp.get(), temp.Length(), pos - start, txtURL);
+      }
+
+      if (!txtURL.IsEmpty() &&
+          CheckURLAndCreateHTML(txtURL, desc, check, outputHTML)) {
+        replaceBefore = resultReplaceBefore;
+        replaceAfter = resultReplaceAfter;
+        state[check] = success;
+      }
+    }  // if
+  }    // for
+  return state[check] == success;
+}
+
+static inline bool IsAlpha(const uint32_t aChar) {
+  return mozilla::unicode::GetGenCategory(aChar) == nsUGenCategory::kLetter;
+}
+
+static inline bool IsDigit(const uint32_t aChar) {
+  return mozilla::unicode::GetGenCategory(aChar) == nsUGenCategory::kNumber;
+}
+
+bool mozTXTToHTMLConv::ItMatchesDelimited(const char16_t* aInString,
+                                          int32_t aInLength,
+                                          const char16_t* rep, int32_t aRepLen,
+                                          LIMTYPE before, LIMTYPE after) {
+  // this little method gets called a LOT. I found we were spending a
+  // lot of time just calculating the length of the variable "rep"
+  // over and over again every time we called it. So we're now passing
+  // an integer in here.
+  int32_t textLen = aInLength;
+
+  if (((before == LT_IGNORE && (after == LT_IGNORE || after == LT_DELIMITER)) &&
+       textLen < aRepLen) ||
+      ((before != LT_IGNORE || (after != LT_IGNORE && after != LT_DELIMITER)) &&
+       textLen < aRepLen + 1) ||
+      (before != LT_IGNORE && after != LT_IGNORE && after != LT_DELIMITER &&
+       textLen < aRepLen + 2)) {
+    return false;
+  }
+
+  uint32_t text0 = aInString[0];
+  if (aInLength > 1 && NS_IS_SURROGATE_PAIR(text0, aInString[1])) {
+    text0 = SURROGATE_TO_UCS4(text0, aInString[1]);
+  }
+  // find length of the char/cluster to be ignored
+  int32_t ignoreLen = before == LT_IGNORE ? 0 : 1;
+  if (ignoreLen) {
+    GraphemeClusterBreakIteratorUtf16 ci(
+        Span<const char16_t>(aInString, aInLength));
+    ignoreLen = *ci.Next();
+  }
+
+  int32_t afterIndex = aRepLen + ignoreLen;
+  uint32_t textAfterPos = aInString[afterIndex];
+  if (aInLength > afterIndex + 1 &&
+      NS_IS_SURROGATE_PAIR(textAfterPos, aInString[afterIndex + 1])) {
+    textAfterPos = SURROGATE_TO_UCS4(textAfterPos, aInString[afterIndex + 1]);
+  }
+
+  return !((before == LT_ALPHA && !IsAlpha(text0)) ||
+           (before == LT_DIGIT && !IsDigit(text0)) ||
+           (before == LT_DELIMITER &&
+            (IsAlpha(text0) || IsDigit(text0) || text0 == *rep)) ||
+           (after == LT_ALPHA && !IsAlpha(textAfterPos)) ||
+           (after == LT_DIGIT && !IsDigit(textAfterPos)) ||
+           (after == LT_DELIMITER &&
+            (IsAlpha(textAfterPos) || IsDigit(textAfterPos) ||
+             textAfterPos == *rep)) ||
+           !Substring(Substring(aInString, aInString + aInLength), ignoreLen,
+                      aRepLen)
+                .Equals(Substring(rep, rep + aRepLen),
+                        nsCaseInsensitiveStringComparator));
+}
+
+uint32_t mozTXTToHTMLConv::NumberOfMatches(const char16_t* aInString,
+                                           int32_t aInStringLength,
+                                           const char16_t* rep, int32_t aRepLen,
+                                           LIMTYPE before, LIMTYPE after) {
+  uint32_t result = 0;
+
+  // Limit lookahead length to avoid pathological O(n^2) behavior; looking so
+  // far ahead is unlikely to be important for cases where styling marked-up
+  // fragments is actually useful anyhow.
+  const uint32_t len =
+      std::min(2000u, mozilla::AssertedCast<uint32_t>(aInStringLength));
+  GraphemeClusterBreakIteratorUtf16 ci(Span<const char16_t>(aInString, len));
+  for (uint32_t pos = 0; pos < len; pos = *ci.Next()) {
+    if (ItMatchesDelimited(aInString + pos, aInStringLength - pos, rep, aRepLen,
+                           before, after)) {
+      result++;
+    }
+  }
+  return result;
+}
+
+// NOTE: the converted html for the phrase is appended to aOutString
+// tagHTML and attributeHTML are plain ASCII (literal strings, in fact)
+bool mozTXTToHTMLConv::StructPhraseHit(
+    const char16_t* aInString, int32_t aInStringLength, bool col0,
+    const char16_t* tagTXT, int32_t aTagTXTLen, const char* tagHTML,
+    const char* attributeHTML, nsAString& aOutString, uint32_t& openTags) {
+  /* We're searching for the following pattern:
+     LT_DELIMITER - "*" - ALPHA -
+     [ some text (maybe more "*"-pairs) - ALPHA ] "*" - LT_DELIMITER.
+     <strong> is only inserted, if existence of a pair could be verified
+     We use the first opening/closing tag, if we can choose */
+
+  const char16_t* newOffset = aInString;
+  int32_t newLength = aInStringLength;
+  if (!col0)  // skip the first element?
+  {
+    newOffset = &aInString[1];
+    newLength = aInStringLength - 1;
+  }
+
+  // opening tag
+  if (ItMatchesDelimited(aInString, aInStringLength, tagTXT, aTagTXTLen,
+                         (col0 ? LT_IGNORE : LT_DELIMITER),
+                         LT_ALPHA)  // is opening tag
+      && NumberOfMatches(newOffset, newLength, tagTXT, aTagTXTLen, LT_ALPHA,
+                         LT_DELIMITER)  // remaining closing tags
+             > openTags) {
+    openTags++;
+    aOutString.Append('<');
+    aOutString.AppendASCII(tagHTML);
+    aOutString.Append(char16_t(' '));
+    aOutString.AppendASCII(attributeHTML);
+    aOutString.AppendLiteral("><span class=\"moz-txt-tag\">");
+    aOutString.Append(tagTXT);
+    aOutString.AppendLiteral("</span>");
+    return true;
+  }
+
+  // closing tag
+  if (openTags > 0 && ItMatchesDelimited(aInString, aInStringLength, tagTXT,
+                                         aTagTXTLen, LT_ALPHA, LT_DELIMITER)) {
+    openTags--;
+    aOutString.AppendLiteral("<span class=\"moz-txt-tag\">");
+    aOutString.Append(tagTXT);
+    aOutString.AppendLiteral("</span></");
+    aOutString.AppendASCII(tagHTML);
+    aOutString.Append(char16_t('>'));
+    return true;
+  }
+
+  return false;
+}
+
+bool mozTXTToHTMLConv::SmilyHit(const char16_t* aInString, int32_t aLength,
+                                bool col0, const char* tagTXT,
+                                const nsString& imageName, nsString& outputHTML,
+                                int32_t& glyphTextLen) {
+  if (!aInString || !tagTXT || imageName.IsEmpty()) return false;
+
+  int32_t tagLen = strlen(tagTXT);
+
+  uint32_t delim = (col0 ? 0 : 1) + tagLen;
+
+  if ((col0 || IsSpace(aInString[0])) &&
+      (aLength <= int32_t(delim) || IsSpace(aInString[delim]) ||
+       (aLength > int32_t(delim + 1) &&
+        (aInString[delim] == '.' || aInString[delim] == ',' ||
+         aInString[delim] == ';' || aInString[delim] == '8' ||
+         aInString[delim] == '>' || aInString[delim] == '!' ||
+         aInString[delim] == '?') &&
+        IsSpace(aInString[delim + 1]))) &&
+      ItMatchesDelimited(aInString, aLength,
+                         NS_ConvertASCIItoUTF16(tagTXT).get(), tagLen,
+                         col0 ? LT_IGNORE : LT_DELIMITER, LT_IGNORE)
+      // Note: tests at different pos for LT_IGNORE and LT_DELIMITER
+  ) {
+    if (!col0) {
+      outputHTML.Truncate();
+      outputHTML.Append(char16_t(' '));
+    }
+
+    outputHTML.Append(imageName);  // emoji unicode
+    glyphTextLen = (col0 ? 0 : 1) + tagLen;
+    return true;
+  }
+
+  return false;
+}
+
+// the glyph is appended to aOutputString instead of the original string...
+bool mozTXTToHTMLConv::GlyphHit(const char16_t* aInString, int32_t aInLength,
+                                bool col0, nsAString& aOutputString,
+                                int32_t& glyphTextLen) {
+  char16_t text0 = aInString[0];
+  char16_t text1 = aInString[1];
+  char16_t firstChar = (col0 ? text0 : text1);
+
+  // temporary variable used to store the glyph html text
+  nsAutoString outputHTML;
+  bool bTestSmilie;
+  bool bArg = false;
+  int i;
+
+  // refactor some of this mess to avoid code duplication and speed execution a
+  // bit there are two cases that need to be tried one after another. To avoid a
+  // lot of duplicate code, rolling into a loop
+
+  i = 0;
+  while (i < 2) {
+    bTestSmilie = false;
+    if (!i && (firstChar == ':' || firstChar == ';' || firstChar == '=' ||
+               firstChar == '>' || firstChar == '8' || firstChar == 'O')) {
+      // first test passed
+
+      bTestSmilie = true;
+      bArg = col0;
+    }
+    if (i && col0 &&
+        (text1 == ':' || text1 == ';' || text1 == '=' || text1 == '>' ||
+         text1 == '8' || text1 == 'O')) {
+      // second test passed
+
+      bTestSmilie = true;
+      bArg = false;
+    }
+    if (bTestSmilie && (SmilyHit(aInString, aInLength, bArg, ":-)",
+                                 u"🙂"_ns,  // smile, U+1F642
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":)",
+                                 u"🙂"_ns,  // smile, U+1F642
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":-D",
+                                 u"😂"_ns,  // laughing, U+1F602
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":-(",
+                                 u"🙁"_ns,  // frown, U+1F641
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":(",
+                                 u"🙁"_ns,  // frown, U+1F641
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":$",
+                                 u"😳"_ns,  // embarassed, U+1F633
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ";-)",
+                                 u"😉"_ns,  // wink, U+1F609
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, col0, ";)",
+                                 u"😉"_ns,  // wink, U+1F609
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":-\\",
+                                 u"😕"_ns,  // undecided, U+1F615
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":-P",
+                                 u"😛"_ns,  // tongue, U+1F61B
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ";-P",
+                                 u"😜"_ns,  // winking face with tongue, U+1F61C
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, "=-O",
+                                 u"😮"_ns,  // surprise, U+1F62E
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":-*",
+                                 u"😘"_ns,  // kiss, U+1F618
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ">:o",
+                                 u"🤬"_ns,  // swearing, U+1F92C
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ">:-o",
+                                 u"🤬"_ns,  // swearing, U+1F92C
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ">:(",
+                                 u"😠"_ns,  // angry, U+1F620
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ">:-(",
+                                 u"😠"_ns,  // angry, U+1F620
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, "8-)",
+                                 u"😎"_ns,  // cool, U+1F60E
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":-$",
+                                 u"🤑"_ns,  // money, U+1F911
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":-!",
+                                 u"😬"_ns,  // foot, U+1F62C
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, "O:-)",
+                                 u"😇"_ns,  // innocent, U+1F607
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":'(",
+                                 u"😭"_ns,  // cry, U+1F62D
+                                 outputHTML, glyphTextLen) ||
+
+                        SmilyHit(aInString, aInLength, bArg, ":-X",
+                                 u"🤐"_ns,  // sealed, U+1F910
+                                 outputHTML, glyphTextLen))) {
+      aOutputString.Append(outputHTML);
+      return true;
+    }
+    i++;
+  }
+  if (text0 == '\f') {
+    aOutputString.AppendLiteral("<span class='moz-txt-formfeed'></span>");
+    glyphTextLen = 1;
+    return true;
+  }
+  if (text0 == '+' || text1 == '+') {
+    if (ItMatchesDelimited(aInString, aInLength, u" +/-", 4, LT_IGNORE,
+                           LT_IGNORE)) {
+      aOutputString.AppendLiteral(" &plusmn;");
+      glyphTextLen = 4;
+      return true;
+    }
+    if (col0 && ItMatchesDelimited(aInString, aInLength, u"+/-", 3, LT_IGNORE,
+                                   LT_IGNORE)) {
+      aOutputString.AppendLiteral("&plusmn;");
+      glyphTextLen = 3;
+      return true;
+    }
+  }
+
+  // x^2  =>  x<sup>2</sup>,   also handle powers x^-2,  x^0.5
+  // implement regular expression /[\dA-Za-z\)\]}]\^-?\d+(\.\d+)*[^\dA-Za-z]/
+  if (text1 == '^' &&
+      (IsAsciiDigit(text0) || IsAsciiAlpha(text0) || text0 == ')' ||
+       text0 == ']' || text0 == '}') &&
+      ((2 < aInLength && IsAsciiDigit(aInString[2])) ||
+       (3 < aInLength && aInString[2] == '-' && IsAsciiDigit(aInString[3])))) {
+    // Find first non-digit
+    int32_t delimPos = 3;  // skip "^" and first digit (or '-')
+    for (; delimPos < aInLength &&
+           (IsAsciiDigit(aInString[delimPos]) ||
+            (aInString[delimPos] == '.' && delimPos + 1 < aInLength &&
+             IsAsciiDigit(aInString[delimPos + 1])));
+         delimPos++) {
+      ;
+    }
+
+    if (delimPos < aInLength && IsAsciiAlpha(aInString[delimPos])) {
+      return false;
+    }
+
+    outputHTML.Truncate();
+    outputHTML += text0;
+    outputHTML.AppendLiteral(
+        "<sup class=\"moz-txt-sup\">"
+        "<span style=\"display:inline-block;width:0;height:0;overflow:hidden\">"
+        "^</span>");
+
+    aOutputString.Append(outputHTML);
+    aOutputString.Append(&aInString[2], delimPos - 2);
+    aOutputString.AppendLiteral("</sup>");
+
+    glyphTextLen = delimPos /* - 1 + 1 */;
+    return true;
+  }
+  /*
+   The following strings are not substituted:
+   |TXT   |HTML     |Reason
+   +------+---------+----------
+    ->     &larr;    Bug #454
+    =>     &lArr;    dito
+    <-     &rarr;    dito
+    <=     &rArr;    dito
+    (tm)   &trade;   dito
+    1/4    &frac14;  is triggered by 1/4 Part 1, 2/4 Part 2, ...
+    3/4    &frac34;  dito
+    1/2    &frac12;  similar
+  */
+  return false;
+}
+
+/***************************************************************************
+  Library-internal Interface
+****************************************************************************/
+
+NS_IMPL_ISUPPORTS(mozTXTToHTMLConv, mozITXTToHTMLConv, nsIStreamConverter,
+                  nsIThreadRetargetableStreamListener, nsIStreamListener,
+                  nsIRequestObserver)
+
+int32_t mozTXTToHTMLConv::CiteLevelTXT(const char16_t* line,
+                                       uint32_t& logLineStart) {
+  int32_t result = 0;
+  int32_t lineLength = NS_strlen(line);
+
+  bool moreCites = true;
+  while (moreCites) {
+    /* E.g. the following lines count as quote:
+
+       > text
+       //#ifdef QUOTE_RECOGNITION_AGGRESSIVE
+       >text
+       //#ifdef QUOTE_RECOGNITION_AGGRESSIVE
+           > text
+       ] text
+       USER> text
+       USER] text
+       //#endif
+
+       logLineStart is the position of "t" in this example
+    */
+    uint32_t i = logLineStart;
+
+#ifdef QUOTE_RECOGNITION_AGGRESSIVE
+    for (; int32_t(i) < lineLength && IsSpace(line[i]); i++)
+      ;
+    for (; int32_t(i) < lineLength && IsAsciiAlpha(line[i]) &&
+           nsCRT::IsUpper(line[i]);
+         i++)
+      ;
+    if (int32_t(i) < lineLength && (line[i] == '>' || line[i] == ']'))
+#else
+    if (int32_t(i) < lineLength && line[i] == '>')
+#endif
+    {
+      i++;
+      if (int32_t(i) < lineLength && line[i] == ' ') i++;
+      // sendmail/mbox
+      // Placed here for performance increase
+      const char16_t* indexString = &line[logLineStart];
+      // here, |logLineStart < lineLength| is always true
+      uint32_t minlength = std::min(uint32_t(6), NS_strlen(indexString));
+      if (Substring(indexString, indexString + minlength)
+              .Equals(Substring(u">From "_ns, 0, minlength),
+                      nsCaseInsensitiveStringComparator)) {
+        // XXX RFC2646
+        moreCites = false;
+      } else {
+        result++;
+        logLineStart = i;
+      }
+    } else {
+      moreCites = false;
+    }
+  }
+
+  return result;
+}
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::ScanTXT(const nsAString& aInString, uint32_t whattodo,
+                          nsAString& aOutString) {
+  if (aInString.Length() == 0) {
+    aOutString.Truncate();
+    return NS_OK;
+  }
+
+  if (!aOutString.SetCapacity(uint32_t(aInString.Length() * growthRate),
+                              mozilla::fallible)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  bool doURLs = 0 != (whattodo & kURLs);
+  bool doGlyphSubstitution = 0 != (whattodo & kGlyphSubstitution);
+  bool doStructPhrase = 0 != (whattodo & kStructPhrase);
+
+  uint32_t structPhrase_strong = 0;  // Number of currently open tags
+  uint32_t structPhrase_underline = 0;
+  uint32_t structPhrase_italic = 0;
+  uint32_t structPhrase_code = 0;
+
+  uint32_t endOfLastURLOutput = 0;
+
+  nsAutoString outputHTML;  // moved here for performance increase
+
+  const char16_t* rawInputString = aInString.BeginReading();
+  uint32_t inLength = aInString.Length();
+
+  const Span<const char16_t> inString(aInString);
+  GraphemeClusterBreakIteratorUtf16 ci(inString);
+  uint32_t i = 0;
+  while (i < inLength) {
+    if (doGlyphSubstitution) {
+      int32_t glyphTextLen;
+      if (GlyphHit(&rawInputString[i], inLength - i, i == 0, aOutString,
+                   glyphTextLen)) {
+        i = *ci.Seek(i + glyphTextLen - 1);
+        continue;
+      }
+    }
+
+    if (doStructPhrase) {
+      const char16_t* newOffset = rawInputString;
+      int32_t newLength = aInString.Length();
+      if (i > 0)  // skip the first element?
+      {
+        GraphemeClusterBreakReverseIteratorUtf16 ri(
+            Span<const char16_t>(rawInputString, i));
+        Maybe<uint32_t> nextPos = ri.Next();
+        newOffset += *nextPos;
+        newLength -= *nextPos;
+      }
+
+      switch (aInString[i])  // Performance increase
+      {
+        case '*':
+          if (StructPhraseHit(newOffset, newLength, i == 0, u"*", 1, "b",
+                              "class=\"moz-txt-star\"", aOutString,
+                              structPhrase_strong)) {
+            i = *ci.Next();
+            continue;
+          }
+          break;
+        case '/':
+          if (StructPhraseHit(newOffset, newLength, i == 0, u"/", 1, "i",
+                              "class=\"moz-txt-slash\"", aOutString,
+                              structPhrase_italic)) {
+            i = *ci.Next();
+            continue;
+          }
+          break;
+        case '_':
+          if (StructPhraseHit(newOffset, newLength, i == 0, u"_", 1,
+                              "span" /* <u> is deprecated */,
+                              "class=\"moz-txt-underscore\"", aOutString,
+                              structPhrase_underline)) {
+            i = *ci.Next();
+            continue;
+          }
+          break;
+        case '|':
+          if (StructPhraseHit(newOffset, newLength, i == 0, u"|", 1, "code",
+                              "class=\"moz-txt-verticalline\"", aOutString,
+                              structPhrase_code)) {
+            i = *ci.Next();
+            continue;
+          }
+          break;
+      }
+    }
+
+    if (doURLs) {
+      switch (aInString[i]) {
+        case ':':
+        case '@':
+        case '.':
+          if ((i == 0 || ((i > 0) && aInString[i - 1] != ' ')) &&
+              ((i == aInString.Length() - 1) ||
+               (aInString[i + 1] != ' ')))  // Performance increase
+          {
+            int32_t replaceBefore;
+            int32_t replaceAfter;
+            if (FindURL(rawInputString, aInString.Length(), i, whattodo,
+                        outputHTML, replaceBefore, replaceAfter) &&
+                structPhrase_strong + structPhrase_italic +
+                        structPhrase_underline + structPhrase_code ==
+                    0
+                /* workaround for bug #19445 */) {
+              // Don't cut into previously inserted HTML (bug 1509493)
+              if (aOutString.Length() - replaceBefore < endOfLastURLOutput) {
+                break;
+              }
+              aOutString.Cut(aOutString.Length() - replaceBefore,
+                             replaceBefore);
+              aOutString += outputHTML;
+              endOfLastURLOutput = aOutString.Length();
+              i = *ci.Seek(i + replaceAfter);
+              continue;
+            }
+          }
+          break;
+      }  // switch
+    }
+
+    switch (aInString[i]) {
+      // Special symbols
+      case '<':
+      case '>':
+      case '&':
+        EscapeChar(aInString[i], aOutString, false);
+        i = *ci.Next();
+        break;
+      // Normal characters
+      default: {
+        const uint32_t oldIdx = i;
+        i = *ci.Next();
+        aOutString.Append(inString.FromTo(oldIdx, i));
+        break;
+      }
+    }
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::ScanHTML(const nsAString& input, uint32_t whattodo,
+                           nsAString& aOutString) {
+  const nsPromiseFlatString& aInString = PromiseFlatString(input);
+  if (!aOutString.SetCapacity(uint32_t(aInString.Length() * growthRate),
+                              mozilla::fallible)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  // some common variables we were recalculating
+  // every time inside the for loop...
+  int32_t lengthOfInString = aInString.Length();
+  const char16_t* uniBuffer = aInString.get();
+
+#ifdef DEBUG_BenB_Perf
+  PRTime parsing_start = PR_IntervalNow();
+#endif
+
+  // Look for simple entities not included in a tags and scan them.
+  // Skip all tags ("<[...]>") and content in an a link tag ("<a [...]</a>"),
+  // comment tag ("<!--[...]-->"), style tag, script tag or head tag.
+  // Unescape the rest (text between tags) and pass it to ScanTXT.
+  nsAutoCString canFollow(" \f\n\r\t>");
+  for (int32_t i = 0; i < lengthOfInString;) {
+    if (aInString[i] == '<')  // html tag
+    {
+      int32_t start = i;
+      if (i + 2 < lengthOfInString && nsCRT::ToLower(aInString[i + 1]) == 'a' &&
+          canFollow.FindChar(aInString[i + 2]) != kNotFound)
+      // if a tag, skip until </a>.
+      // Make sure there's a white-space character after, not to match "abbr".
+      {
+        i = aInString.LowerCaseFindASCII("</a>", i);
+        if (i == kNotFound) {
+          i = lengthOfInString;
+        } else {
+          i += 4;
+        }
+      } else if (Substring(aInString, i + 1, 3).LowerCaseEqualsASCII("!--"))
+      // if out-commended code, skip until -->
+      {
+        i = aInString.Find(u"-->", i);
+        if (i == kNotFound) {
+          i = lengthOfInString;
+        } else {
+          i += 3;
+        }
+      } else if (i + 6 < lengthOfInString &&
+                 Substring(aInString, i + 1, 5).LowerCaseEqualsASCII("style") &&
+                 canFollow.FindChar(aInString[i + 6]) != kNotFound)
+      // if style tag, skip until </style>
+      {
+        i = aInString.LowerCaseFindASCII("</style>", i);
+        if (i == kNotFound) {
+          i = lengthOfInString;
+        } else {
+          i += 8;
+        }
+      } else if (i + 7 < lengthOfInString &&
+                 Substring(aInString, i + 1, 6)
+                     .LowerCaseEqualsASCII("script") &&
+                 canFollow.FindChar(aInString[i + 7]) != kNotFound)
+      // if script tag, skip until </script>
+      {
+        i = aInString.LowerCaseFindASCII("</script>", i);
+        if (i == kNotFound) {
+          i = lengthOfInString;
+        } else {
+          i += 9;
+        }
+      } else if (i + 5 < lengthOfInString &&
+                 Substring(aInString, i + 1, 4).LowerCaseEqualsASCII("head") &&
+                 canFollow.FindChar(aInString[i + 5]) != kNotFound)
+      // if head tag, skip until </head>
+      // Make sure not to match <header>.
+      {
+        i = aInString.LowerCaseFindASCII("</head>", i);
+        if (i == kNotFound) {
+          i = lengthOfInString;
+        } else {
+          i += 7;
+        }
+      } else  // just skip tag (attributes etc.)
+      {
+        i = aInString.FindChar('>', i);
+        if (i == kNotFound) {
+          i = lengthOfInString;
+        } else {
+          i++;
+        }
+      }
+      aOutString.Append(&uniBuffer[start], i - start);
+    } else {
+      uint32_t start = uint32_t(i);
+      i = aInString.FindChar('<', i);
+      if (i == kNotFound) i = lengthOfInString;
+
+      nsAutoStringN<256> tempString;
+      tempString.SetCapacity(uint32_t((uint32_t(i) - start) * growthRate));
+      UnescapeStr(uniBuffer, start, uint32_t(i) - start, tempString);
+      ScanTXT(tempString, whattodo, aOutString);
+    }
+  }
+
+#ifdef DEBUG_BenB_Perf
+  printf("ScanHTML time:    %d ms\n",
+         PR_IntervalToMilliseconds(PR_IntervalNow() - parsing_start));
+#endif
+  return NS_OK;
+}
+
+/****************************************************************************
+  XPCOM Interface
+*****************************************************************************/
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::Convert(nsIInputStream* aFromStream, const char* aFromType,
+                          const char* aToType, nsISupports* aCtxt,
+                          nsIInputStream** _retval) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::AsyncConvertData(const char* aFromType, const char* aToType,
+                                   nsIStreamListener* aListener,
+                                   nsISupports* aCtxt) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::GetConvertedType(const nsACString& aFromType,
+                                   nsIChannel* aChannel, nsACString& aToType) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::OnDataAvailable(nsIRequest* request, nsIInputStream* inStr,
+                                  uint64_t sourceOffset, uint32_t count) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::OnDataFinished(nsresult aStatus) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::CheckListenerChain() { return NS_ERROR_NOT_IMPLEMENTED; }
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::OnStartRequest(nsIRequest* request) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::OnStopRequest(nsIRequest* request, nsresult aStatus) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+mozTXTToHTMLConv::CiteLevelTXT(const char16_t* line, uint32_t* logLineStart,
+                               uint32_t* _retval) {
+  if (!logLineStart || !_retval || !line) return NS_ERROR_NULL_POINTER;
+  *_retval = CiteLevelTXT(line, *logLineStart);
+  return NS_OK;
+}
+
+nsresult MOZ_NewTXTToHTMLConv(mozTXTToHTMLConv** aConv) {
+  MOZ_ASSERT(aConv != nullptr, "null ptr");
+  if (!aConv) return NS_ERROR_NULL_POINTER;
+
+  RefPtr<mozTXTToHTMLConv> conv = new mozTXTToHTMLConv();
+  conv.forget(aConv);
+  //    return (*aConv)->Init();
+  return NS_OK;
+}
diff --git a/netwerk/streamconv/converters/mozTXTToHTMLConv.h b/netwerk/streamconv/converters/mozTXTToHTMLConv.h
new file mode 100644
index 0000000000..dbae8edb0f
--- /dev/null
+++ b/netwerk/streamconv/converters/mozTXTToHTMLConv.h
@@ -0,0 +1,286 @@
+/* -*- 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/. */
+
+/**
+  Description: Currently only functions to enhance plain text with HTML tags.
+  See mozITXTToHTMLConv. Stream conversion is defunct.
+*/
+
+#ifndef _mozTXTToHTMLConv_h__
+#define _mozTXTToHTMLConv_h__
+
+#include "mozITXTToHTMLConv.h"
+#include "nsIThreadRetargetableStreamListener.h"
+#include "nsString.h"
+#include "nsCOMPtr.h"
+
+class nsIIOService;
+
+class mozTXTToHTMLConv : public mozITXTToHTMLConv {
+  virtual ~mozTXTToHTMLConv() = default;
+
+  //////////////////////////////////////////////////////////
+ public:
+  //////////////////////////////////////////////////////////
+
+  mozTXTToHTMLConv() = default;
+  NS_DECL_ISUPPORTS
+
+  NS_DECL_MOZITXTTOHTMLCONV
+  NS_DECL_NSIREQUESTOBSERVER
+  NS_DECL_NSISTREAMLISTENER
+  NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER
+  NS_DECL_NSISTREAMCONVERTER
+
+  /**
+    see mozITXTToHTMLConv::CiteLevelTXT
+   */
+  int32_t CiteLevelTXT(const char16_t* line, uint32_t& logLineStart);
+
+  //////////////////////////////////////////////////////////
+ protected:
+  //////////////////////////////////////////////////////////
+  nsCOMPtr<nsIIOService>
+      mIOService;  // for performance reasons, cache the netwerk service...
+                   /**
+                     Completes<ul>
+                     <li>Case 1: mailto: "mozilla@bucksch.org" -> "mailto:mozilla@bucksch.org"
+                     <li>Case 2: http:   "www.mozilla.org"     -> "http://www.mozilla.org"
+                     <li>Case 3: ftp:    "ftp.mozilla.org"     -> "ftp://www.mozilla.org"
+                     </ul>
+                     It does no check, if the resulting URL is valid.
+                     @param text (in): abbreviated URL
+                     @param pos (in): position of "@" (case 1) or first "." (case 2 and 3)
+                     @return Completed URL at success and empty string at failure
+                    */
+  void CompleteAbbreviatedURL(const char16_t* aInString, int32_t aInLength,
+                              const uint32_t pos, nsString& aOutString);
+
+  //////////////////////////////////////////////////////////
+ private:
+  //////////////////////////////////////////////////////////
+
+  enum LIMTYPE {
+    LT_IGNORE,     // limitation not checked
+    LT_DELIMITER,  // not alphanumeric and not rep[0]. End of text is also ok.
+    LT_ALPHA,      // alpha char
+    LT_DIGIT
+  };
+
+  /**
+    @param text (in): the string to search through.<p>
+           If before = IGNORE,<br>
+             rep is compared starting at 1. char of text (text[0]),<br>
+             else starting at 2. char of text (text[1]).
+           Chars after "after"-delimiter are ignored.
+    @param rep (in): the string to look for
+    @param aRepLen (in): the number of bytes in the string to look for
+    @param before (in): limitation before rep
+    @param after (in): limitation after rep
+    @return true, if rep is found and limitation spec is met or rep is empty
+  */
+  bool ItMatchesDelimited(const char16_t* aInString, int32_t aInLength,
+                          const char16_t* rep, int32_t aRepLen, LIMTYPE before,
+                          LIMTYPE after);
+
+  /**
+    @param see ItMatchesDelimited
+    @return Number of ItMatchesDelimited in text
+  */
+  uint32_t NumberOfMatches(const char16_t* aInString, int32_t aInStringLength,
+                           const char16_t* rep, int32_t aRepLen, LIMTYPE before,
+                           LIMTYPE after);
+
+  /**
+    Currently only changes "<", ">" and "&". All others stay as they are.<p>
+    "Char" in function name to avoid side effects with nsString(ch)
+    constructors.
+    @param ch (in)
+    @param aStringToAppendto (out) - the string to append the escaped
+                                     string to.
+    @param inAttribute (in) - will escape quotes, too (which is
+                              only needed for attribute values)
+  */
+  void EscapeChar(const char16_t ch, nsAString& aStringToAppendto,
+                  bool inAttribute);
+
+  /**
+    See EscapeChar. Escapes the string in place.
+  */
+  void EscapeStr(nsString& aInString, bool inAttribute);
+
+  /**
+    Currently only reverts "<", ">" and "&". All others stay as they are.<p>
+    @param aInString (in) HTML string
+    @param aStartPos (in) start index into the buffer
+    @param aLength (in) length of the buffer
+    @param aOutString (out) unescaped buffer
+  */
+  void UnescapeStr(const char16_t* aInString, int32_t aStartPos,
+                   int32_t aLength, nsString& aOutString);
+
+  /**
+    <em>Note</em>: I use different strategies to pass context between the
+    functions (full text and pos vs. cutted text and col0, glphyTextLen vs.
+    replaceBefore/-After). It makes some sense, but is hard to understand
+    (maintain) :-(.
+  */
+
+  /**
+    <p><em>Note:</em> replaceBefore + replaceAfter + 1 (for char at pos) chars
+    in text should be replaced by outputHTML.</p>
+    <p><em>Note:</em> This function should be able to process a URL on multiple
+    lines, but currently, ScanForURLs is called for every line, so it can't.</p>
+    @param text (in): includes possibly a URL
+    @param pos (in): position in text, where either ":", "." or "@" are found
+    @param whathasbeendone (in): What the calling ScanTXT did/has to do with the
+                (not-linkified) text, i.e. usually the "whattodo" parameter.
+                (Needed to calculate replaceBefore.) NOT what will be done with
+                the content of the link.
+    @param outputHTML (out): URL with HTML-a tag
+    @param replaceBefore (out): Number of chars of URL before pos
+    @param replaceAfter (out): Number of chars of URL after pos
+    @return URL found
+  */
+  bool FindURL(const char16_t* aInString, int32_t aInLength, const uint32_t pos,
+               const uint32_t whathasbeendone, nsString& outputHTML,
+               int32_t& replaceBefore, int32_t& replaceAfter);
+
+  enum modetype {
+    unknown,
+    RFC1738,    /* Check, if RFC1738, APPENDIX compliant,
+                   like "<URL:http://www.mozilla.org>". */
+    RFC2396E,   /* RFC2396, APPENDIX E allows anglebrackets (like
+                   "<http://www.mozilla.org>") (without "URL:") or
+                   quotation marks(like ""http://www.mozilla.org"").
+                   Also allow email addresses without scheme,
+                   e.g. "<mozilla@bucksch.org>" */
+    freetext,   /* assume heading scheme
+                   with "[a-zA-Z][a-zA-Z0-9+\-\.]*:" like "news:"
+                   (see RFC2396, Section 3.1).
+                   Certain characters (see code) or any whitespace
+                   (including linebreaks) end the URL.
+                   Other certain (punctation) characters (see code)
+                   at the end are stripped off. */
+    abbreviated /* Similar to freetext, but without scheme, e.g.
+                   "www.mozilla.org", "ftp.mozilla.org" and
+                   "mozilla@bucksch.org". */
+                /* RFC1738 and RFC2396E type URLs may use multiple lines,
+                   whitespace is stripped. Special characters like ")" stay intact.*/
+  };
+
+  /**
+   * @param text (in), pos (in): see FindURL
+   * @param check (in): Start must be conform with this mode
+   * @param start (out): Position in text, where URL (including brackets or
+   *             similar) starts
+   * @return |check|-conform start has been found
+   */
+  bool FindURLStart(const char16_t* aInString, int32_t aInLength,
+                    const uint32_t pos, const modetype check, uint32_t& start);
+
+  /**
+   * @param text (in), pos (in): see FindURL
+   * @param check (in): End must be conform with this mode
+   * @param start (in): see FindURLStart
+   * @param end (out): Similar to |start| param of FindURLStart
+   * @return |check|-conform end has been found
+   */
+  bool FindURLEnd(const char16_t* aInString, int32_t aInStringLength,
+                  const uint32_t pos, const modetype check,
+                  const uint32_t start, uint32_t& end);
+
+  /**
+   * @param text (in), pos (in), whathasbeendone (in): see FindURL
+   * @param check (in): Current mode
+   * @param start (in), end (in): see FindURLEnd
+   * @param txtURL (out): Guessed (raw) URL.
+   *             Without whitespace, but not completed.
+   * @param desc (out): Link as shown to the user, but already escaped.
+   *             Should be placed between the <a> and </a> tags.
+   * @param replaceBefore(out), replaceAfter (out): see FindURL
+   */
+  void CalculateURLBoundaries(const char16_t* aInString,
+                              int32_t aInStringLength, const uint32_t pos,
+                              const uint32_t whathasbeendone,
+                              const modetype check, const uint32_t start,
+                              const uint32_t end, nsString& txtURL,
+                              nsString& desc, int32_t& replaceBefore,
+                              int32_t& replaceAfter);
+
+  /**
+   * @param txtURL (in), desc (in): see CalculateURLBoundaries
+   * @param outputHTML (out): see FindURL
+   * @return A valid URL could be found (and creation of HTML successful)
+   */
+  bool CheckURLAndCreateHTML(const nsString& txtURL, const nsString& desc,
+                             const modetype mode, nsString& outputHTML);
+
+  /**
+    @param text (in): line of text possibly with tagTXT.<p>
+                if col0 is true,
+                  starting with tagTXT<br>
+                else
+                  starting one char before tagTXT
+    @param col0 (in): tagTXT is on the beginning of the line (or paragraph).
+                open must be 0 then.
+    @param tagTXT (in): Tag in plaintext to search for, e.g. "*"
+    @param aTagTxtLen (in): length of tagTXT.
+    @param tagHTML (in): HTML-Tag to replace tagTXT with,
+                without "<" and ">", e.g. "strong"
+    @param attributeHTML (in): HTML-attribute to add to opening tagHTML,
+                e.g. "class=txt_star"
+    @param aOutString: string to APPEND the converted html into
+    @param open (in/out): Number of currently open tags of type tagHTML
+    @return Conversion succeeded
+  */
+  bool StructPhraseHit(const char16_t* aInString, int32_t aInStringLength,
+                       bool col0, const char16_t* tagTXT, int32_t aTagTxtLen,
+                       const char* tagHTML, const char* attributeHTML,
+                       nsAString& aOutString, uint32_t& openTags);
+
+  /**
+    @param text (in), col0 (in): see GlyphHit
+    @param tagTXT (in): Smily, see also StructPhraseHit
+    @param imageName (in): the basename of the file that contains the image for
+                           this smilie
+    @param outputHTML (out): new string containing the html for the smily
+    @param glyphTextLen (out): see GlyphHit
+  */
+  bool SmilyHit(const char16_t* aInString, int32_t aLength, bool col0,
+                const char* tagTXT, const nsString& imageName,
+                nsString& outputHTML, int32_t& glyphTextLen);
+
+  /**
+    Checks, if we can replace some chars at the start of line with prettier HTML
+    code.<p>
+    If success is reported, replace the first glyphTextLen chars with outputHTML
+
+    @param text (in): line of text possibly with Glyph.<p>
+                If col0 is true,
+                  starting with Glyph <br><!-- (br not part of text) -->
+                else
+                  starting one char before Glyph
+    @param col0 (in): text starts at the beginning of the line (or paragraph)
+    @param aOutString (out): APPENDS html for the glyph to this string
+    @param glyphTextLen (out): Length of original text to replace
+    @return see StructPhraseHit
+  */
+  bool GlyphHit(const char16_t* aInString, int32_t aInLength, bool col0,
+                nsAString& aOutputString, int32_t& glyphTextLen);
+
+  /**
+    Check if a given url should be linkified.
+    @param aURL (in): url to be checked on.
+  */
+  bool ShouldLinkify(const nsCString& aURL);
+};
+
+// It's said, that Win32 and Mac don't like static const members
+const int32_t mozTXTToHTMLConv_lastMode = 4;
+// Needed (only) by mozTXTToHTMLConv::FindURL
+const int32_t mozTXTToHTMLConv_numberOfModes = 4;  // dito; unknown not counted
+
+#endif
diff --git a/netwerk/streamconv/converters/nsDirIndex.cpp b/netwerk/streamconv/converters/nsDirIndex.cpp
new file mode 100644
index 0000000000..fefe5e1863
--- /dev/null
+++ b/netwerk/streamconv/converters/nsDirIndex.cpp
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 4; 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 "nsDirIndex.h"
+
+NS_IMPL_ISUPPORTS(nsDirIndex, nsIDirIndex)
+
+NS_IMETHODIMP
+nsDirIndex::GetType(uint32_t* aType) {
+  NS_ENSURE_ARG_POINTER(aType);
+
+  *aType = mType;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDirIndex::SetType(uint32_t aType) {
+  mType = aType;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDirIndex::GetLocation(nsACString& aLocation) {
+  aLocation = mLocation;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDirIndex::SetLocation(const nsACString& aLocation) {
+  mLocation = aLocation;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDirIndex::GetSize(int64_t* aSize) {
+  NS_ENSURE_ARG_POINTER(aSize);
+
+  *aSize = mSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDirIndex::SetSize(int64_t aSize) {
+  mSize = aSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDirIndex::GetLastModified(PRTime* aLastModified) {
+  NS_ENSURE_ARG_POINTER(aLastModified);
+
+  *aLastModified = mLastModified;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDirIndex::SetLastModified(PRTime aLastModified) {
+  mLastModified = aLastModified;
+  return NS_OK;
+}
diff --git a/netwerk/streamconv/converters/nsDirIndex.h b/netwerk/streamconv/converters/nsDirIndex.h
new file mode 100644
index 0000000000..eb6009295c
--- /dev/null
+++ b/netwerk/streamconv/converters/nsDirIndex.h
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 4; 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 nsDirIndex_h__
+#define nsDirIndex_h__
+
+#include "nsIDirIndex.h"
+#include "nsString.h"
+#include "mozilla/Attributes.h"
+
+class nsDirIndex final : public nsIDirIndex {
+ private:
+  ~nsDirIndex() = default;
+
+ public:
+  nsDirIndex() = default;
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIDIRINDEX
+
+ protected:
+  uint32_t mType{TYPE_UNKNOWN};
+  nsCString mContentType;
+  nsCString mLocation;
+  nsString mDescription;
+  int64_t mSize{INT64_MAX};
+  PRTime mLastModified{-1LL};
+};
+
+#endif
diff --git a/netwerk/streamconv/converters/nsDirIndexParser.cpp b/netwerk/streamconv/converters/nsDirIndexParser.cpp
new file mode 100644
index 0000000000..600f43a1aa
--- /dev/null
+++ b/netwerk/streamconv/converters/nsDirIndexParser.cpp
@@ -0,0 +1,266 @@
+/* -*- 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/. */
+
+/* This parsing code originally lived in xpfe/components/directory/ - bbaetz */
+
+#include "nsDirIndexParser.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Encoding.h"
+#include "mozilla/StaticPtr.h"
+#include "prprf.h"
+#include "nsCRT.h"
+#include "nsDirIndex.h"
+#include "nsEscape.h"
+#include "nsIDirIndex.h"
+#include "nsIInputStream.h"
+
+using namespace mozilla;
+
+NS_IMPL_ISUPPORTS(nsDirIndexParser, nsIRequestObserver, nsIStreamListener,
+                  nsIDirIndexParser)
+
+void nsDirIndexParser::Init() {
+  mLineStart = 0;
+  mFormat[0] = -1;
+}
+
+NS_IMETHODIMP
+nsDirIndexParser::SetListener(nsIDirIndexListener* aListener) {
+  mListener = aListener;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDirIndexParser::GetListener(nsIDirIndexListener** aListener) {
+  *aListener = do_AddRef(mListener).take();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDirIndexParser::OnStartRequest(nsIRequest* aRequest) { return NS_OK; }
+
+NS_IMETHODIMP
+nsDirIndexParser::OnStopRequest(nsIRequest* aRequest, nsresult aStatusCode) {
+  // Finish up
+  if (mBuf.Length() > (uint32_t)mLineStart) {
+    ProcessData(aRequest);
+  }
+
+  return NS_OK;
+}
+
+nsDirIndexParser::Field nsDirIndexParser::gFieldTable[] = {
+    {"Filename", FIELD_FILENAME},
+    {"Content-Length", FIELD_CONTENTLENGTH},
+    {"Last-Modified", FIELD_LASTMODIFIED},
+    {"File-Type", FIELD_FILETYPE},
+    {nullptr, FIELD_UNKNOWN}};
+
+void nsDirIndexParser::ParseFormat(const char* aFormatStr) {
+  // Parse a "200" format line, and remember the fields and their
+  // ordering in mFormat. Multiple 200 lines stomp on each other.
+  unsigned int formatNum = 0;
+  mFormat[0] = -1;
+
+  do {
+    while (*aFormatStr && nsCRT::IsAsciiSpace(char16_t(*aFormatStr))) {
+      ++aFormatStr;
+    }
+
+    if (!*aFormatStr) break;
+
+    nsAutoCString name;
+    int32_t len = 0;
+    while (aFormatStr[len] && !nsCRT::IsAsciiSpace(char16_t(aFormatStr[len]))) {
+      ++len;
+    }
+    name.Append(aFormatStr, len);
+    aFormatStr += len;
+
+    // Okay, we're gonna monkey with the nsStr. Bold!
+    name.SetLength(nsUnescapeCount(name.BeginWriting()));
+
+    for (Field* i = gFieldTable; i->mName; ++i) {
+      if (name.EqualsIgnoreCase(i->mName)) {
+        mFormat[formatNum] = i->mType;
+        mFormat[++formatNum] = -1;
+        break;
+      }
+    }
+
+  } while (*aFormatStr && (formatNum < (ArrayLength(mFormat) - 1)));
+}
+
+void nsDirIndexParser::ParseData(nsIDirIndex* aIdx, char* aDataStr,
+                                 int32_t aLineLen) {
+  // Parse a "201" data line, using the field ordering specified in
+  // mFormat.
+
+  if (mFormat[0] == -1) {
+    // Ignore if we haven't seen a format yet.
+    return;
+  }
+
+  nsAutoCString filename;
+  int32_t lineLen = aLineLen;
+
+  for (int32_t i = 0; mFormat[i] != -1; ++i) {
+    // If we've exhausted the data before we run out of fields, just bail.
+    if (!*aDataStr || (lineLen < 1)) {
+      return;
+    }
+
+    while ((lineLen > 0) && nsCRT::IsAsciiSpace(*aDataStr)) {
+      ++aDataStr;
+      --lineLen;
+    }
+
+    if (lineLen < 1) {
+      // invalid format, bail
+      return;
+    }
+
+    char* value = aDataStr;
+    if (*aDataStr == '"' || *aDataStr == '\'') {
+      // it's a quoted string. snarf everything up to the next quote character
+      const char quotechar = *(aDataStr++);
+      lineLen--;
+      ++value;
+      while ((lineLen > 0) && *aDataStr != quotechar) {
+        ++aDataStr;
+        --lineLen;
+      }
+      if (lineLen > 0) {
+        *aDataStr++ = '\0';
+        --lineLen;
+      }
+
+      if (!lineLen) {
+        // invalid format, bail
+        return;
+      }
+    } else {
+      // it's unquoted. snarf until we see whitespace.
+      value = aDataStr;
+      while ((lineLen > 0) && (!nsCRT::IsAsciiSpace(*aDataStr))) {
+        ++aDataStr;
+        --lineLen;
+      }
+      if (lineLen > 0) {
+        *aDataStr++ = '\0';
+        --lineLen;
+      }
+      // even if we ran out of line length here, there's still a trailing zero
+      // byte afterwards
+    }
+
+    fieldType t = fieldType(mFormat[i]);
+    switch (t) {
+      case FIELD_FILENAME: {
+        // don't unescape at this point, so that UnEscapeAndConvert() can
+        filename = value;
+        aIdx->SetLocation(filename);
+      } break;
+      case FIELD_CONTENTLENGTH: {
+        int64_t len;
+        int32_t status = PR_sscanf(value, "%lld", &len);
+        if (status == 1) {
+          aIdx->SetSize(len);
+        } else {
+          aIdx->SetSize(UINT64_MAX);  // UINT64_MAX means unknown
+        }
+      } break;
+      case FIELD_LASTMODIFIED: {
+        PRTime tm;
+        nsUnescape(value);
+        if (PR_ParseTimeString(value, false, &tm) == PR_SUCCESS) {
+          aIdx->SetLastModified(tm);
+        }
+      } break;
+      case FIELD_FILETYPE:
+        // unescape in-place
+        nsUnescape(value);
+        if (!nsCRT::strcasecmp(value, "directory")) {
+          aIdx->SetType(nsIDirIndex::TYPE_DIRECTORY);
+        } else if (!nsCRT::strcasecmp(value, "file")) {
+          aIdx->SetType(nsIDirIndex::TYPE_FILE);
+        } else if (!nsCRT::strcasecmp(value, "symbolic-link")) {
+          aIdx->SetType(nsIDirIndex::TYPE_SYMLINK);
+        } else {
+          aIdx->SetType(nsIDirIndex::TYPE_UNKNOWN);
+        }
+        break;
+      case FIELD_UNKNOWN:
+        // ignore
+        break;
+    }
+  }
+}
+
+NS_IMETHODIMP
+nsDirIndexParser::OnDataAvailable(nsIRequest* aRequest, nsIInputStream* aStream,
+                                  uint64_t aSourceOffset, uint32_t aCount) {
+  if (aCount < 1) return NS_OK;
+
+  uint32_t len = mBuf.Length();
+
+  // Ensure that our mBuf has capacity to hold the data we're about to
+  // read.
+  // Before adjusting the capacity, guard against any potential overflow
+  // resulting from the addition of aCount with len. See Bug 1823551.
+  NS_ENSURE_TRUE((UINT32_MAX - aCount) >= len, NS_ERROR_FAILURE);
+  if (!mBuf.SetLength(len + aCount, fallible)) return NS_ERROR_OUT_OF_MEMORY;
+
+  // Now read the data into our buffer.
+  nsresult rv;
+  uint32_t count;
+  rv = aStream->Read(mBuf.BeginWriting() + len, aCount, &count);
+  if (NS_FAILED(rv)) return rv;
+
+  // Set the string's length according to the amount of data we've read.
+  // Note: we know this to work on nsCString. This isn't guaranteed to
+  //       work on other strings.
+  mBuf.SetLength(len + count);
+
+  return ProcessData(aRequest);
+}
+
+nsresult nsDirIndexParser::ProcessData(nsIRequest* aRequest) {
+  if (!mListener) return NS_ERROR_FAILURE;
+
+  while (true) {
+    int32_t eol = mBuf.FindCharInSet("\n\r", mLineStart);
+    if (eol < 0) break;
+    mBuf.SetCharAt(char16_t('\0'), eol);
+
+    const char* line = mBuf.get() + mLineStart;
+
+    int32_t lineLen = eol - mLineStart;
+    mLineStart = eol + 1;
+
+    if (lineLen >= 4) {
+      const char* buf = line;
+
+      if (buf[0] == '2') {
+        if (buf[1] == '0') {
+          if (buf[2] == '0' && buf[3] == ':') {
+            // 200. Define field names
+            ParseFormat(buf + 4);
+          } else if (buf[2] == '1' && buf[3] == ':') {
+            // 201. Field data
+            nsCOMPtr<nsIDirIndex> idx = new nsDirIndex();
+
+            ParseData(idx, ((char*)buf) + 4, lineLen - 4);
+            mListener->OnIndexAvailable(aRequest, idx);
+          }
+        }
+      }
+    }
+  }
+
+  return NS_OK;
+}
diff --git a/netwerk/streamconv/converters/nsDirIndexParser.h b/netwerk/streamconv/converters/nsDirIndexParser.h
new file mode 100644
index 0000000000..291a86337e
--- /dev/null
+++ b/netwerk/streamconv/converters/nsDirIndexParser.h
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 4; 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 __NSDIRINDEX_H_
+#define __NSDIRINDEX_H_
+
+#include "nsString.h"
+#include "nsCOMPtr.h"
+#include "nsIDirIndexListener.h"
+#include "mozilla/RefPtr.h"
+
+class nsIDirIndex;
+class nsITextToSubURI;
+
+/* CID: {a0d6ad32-1dd1-11b2-aa55-a40187b54036} */
+
+class nsDirIndexParser : public nsIDirIndexParser {
+ private:
+  virtual ~nsDirIndexParser() = default;
+
+  nsDirIndexParser() = default;
+  void Init();
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISTREAMLISTENER
+  NS_DECL_NSIREQUESTOBSERVER
+  NS_DECL_NSIDIRINDEXPARSER
+
+  static already_AddRefed<nsIDirIndexParser> CreateInstance() {
+    RefPtr<nsDirIndexParser> parser = new nsDirIndexParser();
+    parser->Init();
+    return parser.forget();
+  }
+
+  enum fieldType {
+    FIELD_UNKNOWN = 0,  // MUST be 0
+    FIELD_FILENAME,
+    FIELD_CONTENTLENGTH,
+    FIELD_LASTMODIFIED,
+    FIELD_FILETYPE
+  };
+
+ protected:
+  nsCOMPtr<nsIDirIndexListener> mListener;
+
+  nsCString mBuf;
+  int32_t mLineStart{0};
+  int mFormat[8]{-1};
+
+  nsresult ProcessData(nsIRequest* aRequest);
+  void ParseFormat(const char* aFormatStr);
+  void ParseData(nsIDirIndex* aIdx, char* aDataStr, int32_t lineLen);
+
+  struct Field {
+    const char* mName;
+    fieldType mType;
+  };
+
+  static Field gFieldTable[];
+};
+
+#endif
diff --git a/netwerk/streamconv/converters/nsHTTPCompressConv.cpp b/netwerk/streamconv/converters/nsHTTPCompressConv.cpp
new file mode 100644
index 0000000000..da430a0611
--- /dev/null
+++ b/netwerk/streamconv/converters/nsHTTPCompressConv.cpp
@@ -0,0 +1,767 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et tw=80 : */
+/* 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 "nsHTTPCompressConv.h"
+#include "nsCOMPtr.h"
+#include "nsCRT.h"
+#include "nsError.h"
+#include "nsIThreadRetargetableStreamListener.h"
+#include "nsStreamUtils.h"
+#include "nsStringStream.h"
+#include "nsComponentManagerUtils.h"
+#include "nsThreadUtils.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_network.h"
+#include "mozilla/Logging.h"
+#include "nsIForcePendingChannel.h"
+#include "nsIRequest.h"
+#include "mozilla/UniquePtrExtensions.h"
+
+// brotli headers
+#undef assert
+#include "assert.h"
+#include "state.h"
+#include "brotli/decode.h"
+
+namespace mozilla {
+namespace net {
+
+extern LazyLogModule gHttpLog;
+#define LOG(args) \
+  MOZ_LOG(mozilla::net::gHttpLog, mozilla::LogLevel::Debug, args)
+
+class BrotliWrapper {
+ public:
+  BrotliWrapper() {
+    BrotliDecoderStateInit(&mState, nullptr, nullptr, nullptr);
+  }
+  ~BrotliWrapper() { BrotliDecoderStateCleanup(&mState); }
+
+  BrotliDecoderState mState{};
+  Atomic<size_t, Relaxed> mTotalOut{0};
+  nsresult mStatus = NS_OK;
+  Atomic<bool, Relaxed> mBrotliStateIsStreamEnd{false};
+
+  nsIRequest* mRequest{nullptr};
+  nsISupports* mContext{nullptr};
+  uint64_t mSourceOffset{0};
+};
+
+// nsISupports implementation
+NS_IMPL_ISUPPORTS(nsHTTPCompressConv, nsIStreamConverter, nsIStreamListener,
+                  nsIRequestObserver, nsICompressConvStats,
+                  nsIThreadRetargetableStreamListener)
+
+// nsFTPDirListingConv methods
+nsHTTPCompressConv::nsHTTPCompressConv() {
+  LOG(("nsHttpCompresssConv %p ctor\n", this));
+  if (NS_IsMainThread()) {
+    mFailUncleanStops =
+        Preferences::GetBool("network.http.enforce-framing.http", false);
+  } else {
+    mFailUncleanStops = false;
+  }
+}
+
+nsHTTPCompressConv::~nsHTTPCompressConv() {
+  LOG(("nsHttpCompresssConv %p dtor\n", this));
+  if (mInpBuffer) {
+    free(mInpBuffer);
+  }
+
+  if (mOutBuffer) {
+    free(mOutBuffer);
+  }
+
+  // For some reason we are not getting Z_STREAM_END.  But this was also seen
+  //    for mozilla bug 198133.  Need to handle this case.
+  if (mStreamInitialized && !mStreamEnded) {
+    inflateEnd(&d_stream);
+  }
+}
+
+NS_IMETHODIMP
+nsHTTPCompressConv::GetDecodedDataLength(uint64_t* aDecodedDataLength) {
+  *aDecodedDataLength = mDecodedDataLength;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsHTTPCompressConv::AsyncConvertData(const char* aFromType, const char* aToType,
+                                     nsIStreamListener* aListener,
+                                     nsISupports* aCtxt) {
+  if (!nsCRT::strncasecmp(aFromType, HTTP_COMPRESS_TYPE,
+                          sizeof(HTTP_COMPRESS_TYPE) - 1) ||
+      !nsCRT::strncasecmp(aFromType, HTTP_X_COMPRESS_TYPE,
+                          sizeof(HTTP_X_COMPRESS_TYPE) - 1)) {
+    mMode = HTTP_COMPRESS_COMPRESS;
+  } else if (!nsCRT::strncasecmp(aFromType, HTTP_GZIP_TYPE,
+                                 sizeof(HTTP_GZIP_TYPE) - 1) ||
+             !nsCRT::strncasecmp(aFromType, HTTP_X_GZIP_TYPE,
+                                 sizeof(HTTP_X_GZIP_TYPE) - 1)) {
+    mMode = HTTP_COMPRESS_GZIP;
+  } else if (!nsCRT::strncasecmp(aFromType, HTTP_DEFLATE_TYPE,
+                                 sizeof(HTTP_DEFLATE_TYPE) - 1)) {
+    mMode = HTTP_COMPRESS_DEFLATE;
+  } else if (!nsCRT::strncasecmp(aFromType, HTTP_BROTLI_TYPE,
+                                 sizeof(HTTP_BROTLI_TYPE) - 1)) {
+    mMode = HTTP_COMPRESS_BROTLI;
+  }
+  LOG(("nsHttpCompresssConv %p AsyncConvertData %s %s mode %d\n", this,
+       aFromType, aToType, (CompressMode)mMode));
+
+  MutexAutoLock lock(mMutex);
+  // hook ourself up with the receiving listener.
+  mListener = aListener;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsHTTPCompressConv::GetConvertedType(const nsACString& aFromType,
+                                     nsIChannel* aChannel,
+                                     nsACString& aToType) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsHTTPCompressConv::OnStartRequest(nsIRequest* request) {
+  LOG(("nsHttpCompresssConv %p onstart\n", this));
+  nsCOMPtr<nsIStreamListener> listener;
+  {
+    MutexAutoLock lock(mMutex);
+    listener = mListener;
+  }
+  return listener->OnStartRequest(request);
+}
+
+NS_IMETHODIMP
+nsHTTPCompressConv::OnStopRequest(nsIRequest* request, nsresult aStatus) {
+  nsresult status = aStatus;
+  LOG(("nsHttpCompresssConv %p onstop %" PRIx32 "\n", this,
+       static_cast<uint32_t>(aStatus)));
+
+  // Framing integrity is enforced for content-encoding: gzip, but not for
+  // content-encoding: deflate. Note that gzip vs deflate is NOT determined
+  // by content sniffing but only via header.
+  if (!mStreamEnded && NS_SUCCEEDED(status) &&
+      (mFailUncleanStops && (mMode == HTTP_COMPRESS_GZIP))) {
+    // This is not a clean end of gzip stream: the transfer is incomplete.
+    status = NS_ERROR_NET_PARTIAL_TRANSFER;
+    LOG(("nsHttpCompresssConv %p onstop partial gzip\n", this));
+  }
+  if (NS_SUCCEEDED(status) && mMode == HTTP_COMPRESS_BROTLI) {
+    nsCOMPtr<nsIForcePendingChannel> fpChannel = do_QueryInterface(request);
+    bool isPending = false;
+    if (request) {
+      request->IsPending(&isPending);
+    }
+    if (fpChannel && !isPending) {
+      fpChannel->ForcePending(true);
+    }
+    bool allowTruncatedEmpty =
+        StaticPrefs::network_compress_allow_truncated_empty_brotli();
+    if (mBrotli && ((allowTruncatedEmpty && NS_FAILED(mBrotli->mStatus)) ||
+                    (!allowTruncatedEmpty && mBrotli->mTotalOut == 0 &&
+                     !mBrotli->mBrotliStateIsStreamEnd))) {
+      status = NS_ERROR_INVALID_CONTENT_ENCODING;
+    }
+    LOG(("nsHttpCompresssConv %p onstop brotlihandler rv %" PRIx32 "\n", this,
+         static_cast<uint32_t>(status)));
+    if (fpChannel && !isPending) {
+      fpChannel->ForcePending(false);
+    }
+  }
+
+  nsCOMPtr<nsIStreamListener> listener;
+  {
+    MutexAutoLock lock(mMutex);
+    listener = mListener;
+  }
+  return listener->OnStopRequest(request, status);
+}
+
+/* static */
+nsresult nsHTTPCompressConv::BrotliHandler(nsIInputStream* stream,
+                                           void* closure, const char* dataIn,
+                                           uint32_t, uint32_t aAvail,
+                                           uint32_t* countRead) {
+  MOZ_ASSERT(stream);
+  nsHTTPCompressConv* self = static_cast<nsHTTPCompressConv*>(closure);
+  *countRead = 0;
+
+  const size_t kOutSize = 128 * 1024;  // just a chunk size, we call in a loop
+  uint8_t* outPtr;
+  size_t outSize;
+  size_t avail = aAvail;
+  BrotliDecoderResult res;
+
+  if (!self->mBrotli) {
+    *countRead = aAvail;
+    return NS_OK;
+  }
+
+  auto outBuffer = MakeUniqueFallible<uint8_t[]>(kOutSize);
+  if (outBuffer == nullptr) {
+    self->mBrotli->mStatus = NS_ERROR_OUT_OF_MEMORY;
+    return self->mBrotli->mStatus;
+  }
+  do {
+    outSize = kOutSize;
+    outPtr = outBuffer.get();
+
+    // brotli api is documented in brotli/dec/decode.h and brotli/dec/decode.c
+    LOG(("nsHttpCompresssConv %p brotlihandler decompress %zu\n", self, avail));
+    size_t totalOut = self->mBrotli->mTotalOut;
+    res = ::BrotliDecoderDecompressStream(
+        &self->mBrotli->mState, &avail,
+        reinterpret_cast<const unsigned char**>(&dataIn), &outSize, &outPtr,
+        &totalOut);
+    outSize = kOutSize - outSize;
+    self->mBrotli->mTotalOut = totalOut;
+    self->mBrotli->mBrotliStateIsStreamEnd =
+        BrotliDecoderIsFinished(&self->mBrotli->mState);
+    LOG(("nsHttpCompresssConv %p brotlihandler decompress rv=%" PRIx32
+         " out=%zu\n",
+         self, static_cast<uint32_t>(res), outSize));
+
+    if (res == BROTLI_DECODER_RESULT_ERROR) {
+      LOG(("nsHttpCompressConv %p marking invalid encoding", self));
+      self->mBrotli->mStatus = NS_ERROR_INVALID_CONTENT_ENCODING;
+      return self->mBrotli->mStatus;
+    }
+
+    // in 'the current implementation' brotli must consume everything before
+    // asking for more input
+    if (res == BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT) {
+      MOZ_ASSERT(!avail);
+      if (avail) {
+        LOG(("nsHttpCompressConv %p did not consume all input", self));
+        self->mBrotli->mStatus = NS_ERROR_UNEXPECTED;
+        return self->mBrotli->mStatus;
+      }
+    }
+
+    auto callOnDataAvailable = [&](uint64_t aSourceOffset, const char* aBuffer,
+                                   uint32_t aCount) {
+      nsresult rv = self->do_OnDataAvailable(self->mBrotli->mRequest,
+                                             aSourceOffset, aBuffer, aCount);
+      LOG(("nsHttpCompressConv %p BrotliHandler ODA rv=%" PRIx32, self,
+           static_cast<uint32_t>(rv)));
+      if (NS_FAILED(rv)) {
+        self->mBrotli->mStatus = rv;
+      }
+
+      return rv;
+    };
+
+    if (outSize > 0) {
+      if (NS_FAILED(callOnDataAvailable(
+              self->mBrotli->mSourceOffset,
+              reinterpret_cast<const char*>(outBuffer.get()), outSize))) {
+        return self->mBrotli->mStatus;
+      }
+    }
+
+    // See bug 1759745. If the decoder has more output data, take it.
+    while (::BrotliDecoderHasMoreOutput(&self->mBrotli->mState)) {
+      outSize = kOutSize;
+      const uint8_t* buffer =
+          ::BrotliDecoderTakeOutput(&self->mBrotli->mState, &outSize);
+      if (NS_FAILED(callOnDataAvailable(self->mBrotli->mSourceOffset,
+                                        reinterpret_cast<const char*>(buffer),
+                                        outSize))) {
+        return self->mBrotli->mStatus;
+      }
+    }
+
+    if (res == BROTLI_DECODER_RESULT_SUCCESS ||
+        res == BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT) {
+      *countRead = aAvail;
+      return NS_OK;
+    }
+    MOZ_ASSERT(res == BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT);
+  } while (res == BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT);
+
+  self->mBrotli->mStatus = NS_ERROR_UNEXPECTED;
+  return self->mBrotli->mStatus;
+}
+
+NS_IMETHODIMP
+nsHTTPCompressConv::OnDataAvailable(nsIRequest* request, nsIInputStream* iStr,
+                                    uint64_t aSourceOffset, uint32_t aCount) {
+  nsresult rv = NS_ERROR_INVALID_CONTENT_ENCODING;
+  uint32_t streamLen = aCount;
+  LOG(("nsHttpCompressConv %p OnDataAvailable %d", this, aCount));
+
+  if (streamLen == 0) {
+    NS_ERROR("count of zero passed to OnDataAvailable");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (mStreamEnded) {
+    // Hmm... this may just indicate that the data stream is done and that
+    // what's left is either metadata or padding of some sort.... throwing
+    // it out is probably the safe thing to do.
+    uint32_t n;
+    return iStr->ReadSegments(NS_DiscardSegment, nullptr, streamLen, &n);
+  }
+
+  switch (mMode) {
+    case HTTP_COMPRESS_GZIP:
+      streamLen = check_header(iStr, streamLen, &rv);
+
+      if (rv != NS_OK) {
+        return rv;
+      }
+
+      if (streamLen == 0) {
+        return NS_OK;
+      }
+
+      [[fallthrough]];
+
+    case HTTP_COMPRESS_DEFLATE:
+
+      if (mInpBuffer != nullptr && streamLen > mInpBufferLen) {
+        unsigned char* originalInpBuffer = mInpBuffer;
+        if (!(mInpBuffer = (unsigned char*)realloc(
+                  originalInpBuffer, mInpBufferLen = streamLen))) {
+          free(originalInpBuffer);
+        }
+
+        if (mOutBufferLen < streamLen * 2) {
+          unsigned char* originalOutBuffer = mOutBuffer;
+          if (!(mOutBuffer = (unsigned char*)realloc(
+                    mOutBuffer, mOutBufferLen = streamLen * 3))) {
+            free(originalOutBuffer);
+          }
+        }
+
+        if (mInpBuffer == nullptr || mOutBuffer == nullptr) {
+          return NS_ERROR_OUT_OF_MEMORY;
+        }
+      }
+
+      if (mInpBuffer == nullptr) {
+        mInpBuffer = (unsigned char*)malloc(mInpBufferLen = streamLen);
+      }
+
+      if (mOutBuffer == nullptr) {
+        mOutBuffer = (unsigned char*)malloc(mOutBufferLen = streamLen * 3);
+      }
+
+      if (mInpBuffer == nullptr || mOutBuffer == nullptr) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+
+      uint32_t unused;
+      iStr->Read((char*)mInpBuffer, streamLen, &unused);
+
+      if (mMode == HTTP_COMPRESS_DEFLATE) {
+        if (!mStreamInitialized) {
+          memset(&d_stream, 0, sizeof(d_stream));
+
+          if (inflateInit(&d_stream) != Z_OK) {
+            return NS_ERROR_FAILURE;
+          }
+
+          mStreamInitialized = true;
+        }
+        d_stream.next_in = mInpBuffer;
+        d_stream.avail_in = (uInt)streamLen;
+
+        mDummyStreamInitialised = false;
+        for (;;) {
+          d_stream.next_out = mOutBuffer;
+          d_stream.avail_out = (uInt)mOutBufferLen;
+
+          int code = inflate(&d_stream, Z_NO_FLUSH);
+          unsigned bytesWritten = (uInt)mOutBufferLen - d_stream.avail_out;
+
+          if (code == Z_STREAM_END) {
+            if (bytesWritten) {
+              rv = do_OnDataAvailable(request, aSourceOffset, (char*)mOutBuffer,
+                                      bytesWritten);
+              if (NS_FAILED(rv)) {
+                return rv;
+              }
+            }
+
+            inflateEnd(&d_stream);
+            mStreamEnded = true;
+            break;
+          }
+          if (code == Z_OK) {
+            if (bytesWritten) {
+              rv = do_OnDataAvailable(request, aSourceOffset, (char*)mOutBuffer,
+                                      bytesWritten);
+              if (NS_FAILED(rv)) {
+                return rv;
+              }
+            }
+          } else if (code == Z_BUF_ERROR) {
+            if (bytesWritten) {
+              rv = do_OnDataAvailable(request, aSourceOffset, (char*)mOutBuffer,
+                                      bytesWritten);
+              if (NS_FAILED(rv)) {
+                return rv;
+              }
+            }
+            break;
+          } else if (code == Z_DATA_ERROR) {
+            // some servers (notably Apache with mod_deflate) don't generate
+            // zlib headers insert a dummy header and try again
+            static char dummy_head[2] = {
+                0x8 + 0x7 * 0x10,
+                (((0x8 + 0x7 * 0x10) * 0x100 + 30) / 31 * 31) & 0xFF,
+            };
+            inflateReset(&d_stream);
+            d_stream.next_in = (Bytef*)dummy_head;
+            d_stream.avail_in = sizeof(dummy_head);
+
+            code = inflate(&d_stream, Z_NO_FLUSH);
+            if (code != Z_OK) {
+              return NS_ERROR_FAILURE;
+            }
+
+            // stop an endless loop caused by non-deflate data being labelled as
+            // deflate
+            if (mDummyStreamInitialised) {
+              NS_WARNING(
+                  "endless loop detected"
+                  " - invalid deflate");
+              return NS_ERROR_INVALID_CONTENT_ENCODING;
+            }
+            mDummyStreamInitialised = true;
+            // reset stream pointers to our original data
+            d_stream.next_in = mInpBuffer;
+            d_stream.avail_in = (uInt)streamLen;
+          } else {
+            return NS_ERROR_INVALID_CONTENT_ENCODING;
+          }
+        } /* for */
+      } else {
+        if (!mStreamInitialized) {
+          memset(&d_stream, 0, sizeof(d_stream));
+
+          if (inflateInit2(&d_stream, -MAX_WBITS) != Z_OK) {
+            return NS_ERROR_FAILURE;
+          }
+
+          mStreamInitialized = true;
+        }
+
+        d_stream.next_in = mInpBuffer;
+        d_stream.avail_in = (uInt)streamLen;
+
+        for (;;) {
+          d_stream.next_out = mOutBuffer;
+          d_stream.avail_out = (uInt)mOutBufferLen;
+
+          int code = inflate(&d_stream, Z_NO_FLUSH);
+          unsigned bytesWritten = (uInt)mOutBufferLen - d_stream.avail_out;
+
+          if (code == Z_STREAM_END) {
+            if (bytesWritten) {
+              rv = do_OnDataAvailable(request, aSourceOffset, (char*)mOutBuffer,
+                                      bytesWritten);
+              if (NS_FAILED(rv)) {
+                return rv;
+              }
+            }
+
+            inflateEnd(&d_stream);
+            mStreamEnded = true;
+            break;
+          }
+          if (code == Z_OK) {
+            if (bytesWritten) {
+              rv = do_OnDataAvailable(request, aSourceOffset, (char*)mOutBuffer,
+                                      bytesWritten);
+              if (NS_FAILED(rv)) {
+                return rv;
+              }
+            }
+          } else if (code == Z_BUF_ERROR) {
+            if (bytesWritten) {
+              rv = do_OnDataAvailable(request, aSourceOffset, (char*)mOutBuffer,
+                                      bytesWritten);
+              if (NS_FAILED(rv)) {
+                return rv;
+              }
+            }
+            break;
+          } else {
+            return NS_ERROR_INVALID_CONTENT_ENCODING;
+          }
+        } /* for */
+      }   /* gzip */
+      break;
+
+    case HTTP_COMPRESS_BROTLI: {
+      if (!mBrotli) {
+        mBrotli = MakeUnique<BrotliWrapper>();
+      }
+
+      mBrotli->mRequest = request;
+      mBrotli->mContext = nullptr;
+      mBrotli->mSourceOffset = aSourceOffset;
+
+      uint32_t countRead;
+      rv = iStr->ReadSegments(BrotliHandler, this, streamLen, &countRead);
+      if (NS_SUCCEEDED(rv)) {
+        rv = mBrotli->mStatus;
+      }
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+    } break;
+
+    default:
+      nsCOMPtr<nsIStreamListener> listener;
+      {
+        MutexAutoLock lock(mMutex);
+        listener = mListener;
+      }
+      rv = listener->OnDataAvailable(request, iStr, aSourceOffset, aCount);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+  } /* switch */
+
+  return NS_OK;
+} /* OnDataAvailable */
+
+// XXX/ruslan: need to implement this too
+
+NS_IMETHODIMP
+nsHTTPCompressConv::Convert(nsIInputStream* aFromStream, const char* aFromType,
+                            const char* aToType, nsISupports* aCtxt,
+                            nsIInputStream** _retval) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+nsresult nsHTTPCompressConv::do_OnDataAvailable(nsIRequest* request,
+                                                uint64_t offset,
+                                                const char* buffer,
+                                                uint32_t count) {
+  if (!mStream) {
+    mStream = do_CreateInstance(NS_STRINGINPUTSTREAM_CONTRACTID);
+    NS_ENSURE_STATE(mStream);
+  }
+
+  mStream->ShareData(buffer, count);
+
+  nsCOMPtr<nsIStreamListener> listener;
+  {
+    MutexAutoLock lock(mMutex);
+    listener = mListener;
+  }
+  nsresult rv = listener->OnDataAvailable(request, mStream, offset, count);
+
+  // Make sure the stream no longer references |buffer| in case our listener
+  // is crazy enough to try to read from |mStream| after ODA.
+  mStream->ShareData("", 0);
+  mDecodedDataLength += count;
+
+  return rv;
+}
+
+#define ASCII_FLAG 0x01  /* bit 0 set: file probably ascii text */
+#define HEAD_CRC 0x02    /* bit 1 set: header CRC present */
+#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
+#define ORIG_NAME 0x08   /* bit 3 set: original file name present */
+#define COMMENT 0x10     /* bit 4 set: file comment present */
+#define RESERVED 0xE0    /* bits 5..7: reserved */
+
+static unsigned gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
+
+uint32_t nsHTTPCompressConv::check_header(nsIInputStream* iStr,
+                                          uint32_t streamLen, nsresult* rs) {
+  enum {
+    GZIP_INIT = 0,
+    GZIP_OS,
+    GZIP_EXTRA0,
+    GZIP_EXTRA1,
+    GZIP_EXTRA2,
+    GZIP_ORIG,
+    GZIP_COMMENT,
+    GZIP_CRC
+  };
+  char c;
+
+  *rs = NS_OK;
+
+  if (mCheckHeaderDone) {
+    return streamLen;
+  }
+
+  while (streamLen) {
+    switch (hMode) {
+      case GZIP_INIT:
+        uint32_t unused;
+        iStr->Read(&c, 1, &unused);
+        streamLen--;
+
+        if (mSkipCount == 0 && ((unsigned)c & 0377) != gz_magic[0]) {
+          *rs = NS_ERROR_INVALID_CONTENT_ENCODING;
+          return 0;
+        }
+
+        if (mSkipCount == 1 && ((unsigned)c & 0377) != gz_magic[1]) {
+          *rs = NS_ERROR_INVALID_CONTENT_ENCODING;
+          return 0;
+        }
+
+        if (mSkipCount == 2 && ((unsigned)c & 0377) != Z_DEFLATED) {
+          *rs = NS_ERROR_INVALID_CONTENT_ENCODING;
+          return 0;
+        }
+
+        mSkipCount++;
+        if (mSkipCount == 4) {
+          mFlags = (unsigned)c & 0377;
+          if (mFlags & RESERVED) {
+            *rs = NS_ERROR_INVALID_CONTENT_ENCODING;
+            return 0;
+          }
+          hMode = GZIP_OS;
+          mSkipCount = 0;
+        }
+        break;
+
+      case GZIP_OS:
+        iStr->Read(&c, 1, &unused);
+        streamLen--;
+        mSkipCount++;
+
+        if (mSkipCount == 6) {
+          hMode = GZIP_EXTRA0;
+        }
+        break;
+
+      case GZIP_EXTRA0:
+        if (mFlags & EXTRA_FIELD) {
+          iStr->Read(&c, 1, &unused);
+          streamLen--;
+          mLen = (uInt)c & 0377;
+          hMode = GZIP_EXTRA1;
+        } else {
+          hMode = GZIP_ORIG;
+        }
+        break;
+
+      case GZIP_EXTRA1:
+        iStr->Read(&c, 1, &unused);
+        streamLen--;
+        mLen |= ((uInt)c & 0377) << 8;
+        mSkipCount = 0;
+        hMode = GZIP_EXTRA2;
+        break;
+
+      case GZIP_EXTRA2:
+        if (mSkipCount == mLen) {
+          hMode = GZIP_ORIG;
+        } else {
+          iStr->Read(&c, 1, &unused);
+          streamLen--;
+          mSkipCount++;
+        }
+        break;
+
+      case GZIP_ORIG:
+        if (mFlags & ORIG_NAME) {
+          iStr->Read(&c, 1, &unused);
+          streamLen--;
+          if (c == 0) hMode = GZIP_COMMENT;
+        } else {
+          hMode = GZIP_COMMENT;
+        }
+        break;
+
+      case GZIP_COMMENT:
+        if (mFlags & COMMENT) {
+          iStr->Read(&c, 1, &unused);
+          streamLen--;
+          if (c == 0) {
+            hMode = GZIP_CRC;
+            mSkipCount = 0;
+          }
+        } else {
+          hMode = GZIP_CRC;
+          mSkipCount = 0;
+        }
+        break;
+
+      case GZIP_CRC:
+        if (mFlags & HEAD_CRC) {
+          iStr->Read(&c, 1, &unused);
+          streamLen--;
+          mSkipCount++;
+          if (mSkipCount == 2) {
+            mCheckHeaderDone = true;
+            return streamLen;
+          }
+        } else {
+          mCheckHeaderDone = true;
+          return streamLen;
+        }
+        break;
+    }
+  }
+  return streamLen;
+}
+
+NS_IMETHODIMP
+nsHTTPCompressConv::CheckListenerChain() {
+  nsCOMPtr<nsIThreadRetargetableStreamListener> listener;
+  {
+    MutexAutoLock lock(mMutex);
+    listener = do_QueryInterface(mListener);
+  }
+
+  if (!listener) {
+    return NS_ERROR_NO_INTERFACE;
+  }
+
+  return listener->CheckListenerChain();
+}
+
+NS_IMETHODIMP
+nsHTTPCompressConv::OnDataFinished(nsresult aStatus) {
+  nsCOMPtr<nsIThreadRetargetableStreamListener> listener;
+
+  {
+    MutexAutoLock lock(mMutex);
+    listener = do_QueryInterface(mListener);
+  }
+
+  if (listener) {
+    return listener->OnDataFinished(aStatus);
+  }
+
+  return NS_OK;
+}
+
+}  // namespace net
+}  // namespace mozilla
+
+nsresult NS_NewHTTPCompressConv(
+    mozilla::net::nsHTTPCompressConv** aHTTPCompressConv) {
+  MOZ_ASSERT(aHTTPCompressConv != nullptr, "null ptr");
+  if (!aHTTPCompressConv) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  RefPtr<mozilla::net::nsHTTPCompressConv> outVal =
+      new mozilla::net::nsHTTPCompressConv();
+  if (!outVal) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  outVal.forget(aHTTPCompressConv);
+  return NS_OK;
+}
diff --git a/netwerk/streamconv/converters/nsHTTPCompressConv.h b/netwerk/streamconv/converters/nsHTTPCompressConv.h
new file mode 100644
index 0000000000..4ba2d9819c
--- /dev/null
+++ b/netwerk/streamconv/converters/nsHTTPCompressConv.h
@@ -0,0 +1,109 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et tw=80 : */
+/* 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/. */
+
+#if !defined(__nsHTTPCompressConv__h__)
+#  define __nsHTTPCompressConv__h__ 1
+
+#  include "nsIStreamConverter.h"
+#  include "nsICompressConvStats.h"
+#  include "nsIThreadRetargetableStreamListener.h"
+#  include "nsCOMPtr.h"
+#  include "mozilla/Atomics.h"
+#  include "mozilla/Mutex.h"
+
+#  include "zlib.h"
+
+class nsIStringInputStream;
+
+#  define NS_HTTPCOMPRESSCONVERTER_CID                 \
+    {                                                  \
+      /* 66230b2b-17fa-4bd3-abf4-07986151022d */       \
+      0x66230b2b, 0x17fa, 0x4bd3, {                    \
+        0xab, 0xf4, 0x07, 0x98, 0x61, 0x51, 0x02, 0x2d \
+      }                                                \
+    }
+
+#  define HTTP_DEFLATE_TYPE "deflate"
+#  define HTTP_GZIP_TYPE "gzip"
+#  define HTTP_X_GZIP_TYPE "x-gzip"
+#  define HTTP_COMPRESS_TYPE "compress"
+#  define HTTP_X_COMPRESS_TYPE "x-compress"
+#  define HTTP_BROTLI_TYPE "br"
+#  define HTTP_IDENTITY_TYPE "identity"
+#  define HTTP_UNCOMPRESSED_TYPE "uncompressed"
+
+namespace mozilla {
+namespace net {
+
+class BrotliWrapper;
+
+class nsHTTPCompressConv : public nsIStreamConverter,
+                           public nsICompressConvStats {
+ public:
+  // nsISupports methods
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIREQUESTOBSERVER
+  NS_DECL_NSISTREAMLISTENER
+  NS_DECL_NSICOMPRESSCONVSTATS
+  NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER
+
+  // nsIStreamConverter methods
+  NS_DECL_NSISTREAMCONVERTER
+
+  nsHTTPCompressConv();
+
+  using CompressMode = enum {
+    HTTP_COMPRESS_GZIP,
+    HTTP_COMPRESS_DEFLATE,
+    HTTP_COMPRESS_COMPRESS,
+    HTTP_COMPRESS_BROTLI,
+    HTTP_COMPRESS_IDENTITY
+  };
+
+ private:
+  virtual ~nsHTTPCompressConv();
+
+  nsCOMPtr<nsIStreamListener>
+      mListener;  // this guy gets the converted data via his OnDataAvailable ()
+  Atomic<CompressMode, Relaxed> mMode{HTTP_COMPRESS_IDENTITY};
+
+  unsigned char* mOutBuffer{nullptr};
+  unsigned char* mInpBuffer{nullptr};
+
+  uint32_t mOutBufferLen{0};
+  uint32_t mInpBufferLen{0};
+
+  UniquePtr<BrotliWrapper> mBrotli;
+
+  nsCOMPtr<nsIStringInputStream> mStream;
+
+  static nsresult BrotliHandler(nsIInputStream* stream, void* closure,
+                                const char* dataIn, uint32_t, uint32_t avail,
+                                uint32_t* countRead);
+
+  nsresult do_OnDataAvailable(nsIRequest* request, uint64_t aSourceOffset,
+                              const char* buffer, uint32_t aCount);
+
+  bool mCheckHeaderDone{false};
+  Atomic<bool> mStreamEnded{false};
+  bool mStreamInitialized{false};
+  bool mDummyStreamInitialised{false};
+  bool mFailUncleanStops;
+
+  z_stream d_stream{};
+  unsigned mLen{0}, hMode{0}, mSkipCount{0}, mFlags{0};
+
+  uint32_t check_header(nsIInputStream* iStr, uint32_t streamLen, nsresult* rs);
+
+  Atomic<uint32_t, Relaxed> mDecodedDataLength{0};
+
+  mutable mozilla::Mutex mMutex MOZ_UNANNOTATED{"nsHTTPCompressConv"};
+};
+
+}  // namespace net
+}  // namespace mozilla
+
+#endif
diff --git a/netwerk/streamconv/converters/nsICompressConvStats.idl b/netwerk/streamconv/converters/nsICompressConvStats.idl
new file mode 100644
index 0000000000..a8837563ed
--- /dev/null
+++ b/netwerk/streamconv/converters/nsICompressConvStats.idl
@@ -0,0 +1,17 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsISupports.idl"
+
+/**
+ * nsICompressConvStats
+ *
+ * This interface allows for the observation of decoded resource sizes
+ */
+[builtinclass, scriptable, uuid(58172ad0-46a9-4893-8fde-cd909c10792a)]
+interface nsICompressConvStats : nsISupports
+{
+    readonly attribute uint64_t decodedDataLength;
+};
diff --git a/netwerk/streamconv/converters/nsIndexedToHTML.cpp b/netwerk/streamconv/converters/nsIndexedToHTML.cpp
new file mode 100644
index 0000000000..efc8962459
--- /dev/null
+++ b/netwerk/streamconv/converters/nsIndexedToHTML.cpp
@@ -0,0 +1,825 @@
+/* -*- Mode: C++; tab-width: 4; 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 "nsIndexedToHTML.h"
+
+#include "mozilla/Encoding.h"
+#include "mozilla/intl/AppDateTimeFormat.h"
+#include "mozilla/intl/LocaleService.h"
+#include "nsIThreadRetargetableStreamListener.h"
+#include "nsNetUtil.h"
+#include "netCore.h"
+#include "nsStringStream.h"
+#include "nsIFile.h"
+#include "nsIFileURL.h"
+#include "nsEscape.h"
+#include "nsIDirIndex.h"
+#include "nsURLHelper.h"
+#include "nsIStringBundle.h"
+#include "nsDirIndexParser.h"
+#include "nsNativeCharsetUtils.h"
+#include "nsString.h"
+#include "nsContentUtils.h"
+#include <algorithm>
+#include "nsIChannel.h"
+#include "mozilla/Unused.h"
+#include "nsIURIMutator.h"
+#include "nsITextToSubURI.h"
+
+using mozilla::intl::LocaleService;
+using namespace mozilla;
+
+NS_IMPL_ISUPPORTS(nsIndexedToHTML, nsIDirIndexListener, nsIStreamConverter,
+                  nsIThreadRetargetableStreamListener, nsIRequestObserver,
+                  nsIStreamListener)
+
+static void AppendNonAsciiToNCR(const nsAString& in, nsCString& out) {
+  nsAString::const_iterator start, end;
+
+  in.BeginReading(start);
+  in.EndReading(end);
+
+  while (start != end) {
+    if (*start < 128) {
+      out.Append(*start++);
+    } else {
+      out.AppendLiteral("&#x");
+      out.AppendInt(*start++, 16);
+      out.Append(';');
+    }
+  }
+}
+
+nsresult nsIndexedToHTML::Create(REFNSIID aIID, void** aResult) {
+  nsresult rv;
+
+  nsIndexedToHTML* _s = new nsIndexedToHTML();
+  if (_s == nullptr) return NS_ERROR_OUT_OF_MEMORY;
+
+  rv = _s->QueryInterface(aIID, aResult);
+  return rv;
+}
+
+nsresult nsIndexedToHTML::Init(nsIStreamListener* aListener) {
+  nsresult rv = NS_OK;
+
+  mListener = aListener;
+
+  nsCOMPtr<nsIStringBundleService> sbs =
+      do_GetService(NS_STRINGBUNDLE_CONTRACTID, &rv);
+  if (NS_FAILED(rv)) return rv;
+  rv = sbs->CreateBundle(NECKO_MSGS_URL, getter_AddRefs(mBundle));
+
+  mExpectAbsLoc = false;
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsIndexedToHTML::Convert(nsIInputStream* aFromStream, const char* aFromType,
+                         const char* aToType, nsISupports* aCtxt,
+                         nsIInputStream** res) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsIndexedToHTML::AsyncConvertData(const char* aFromType, const char* aToType,
+                                  nsIStreamListener* aListener,
+                                  nsISupports* aCtxt) {
+  return Init(aListener);
+}
+
+NS_IMETHODIMP
+nsIndexedToHTML::GetConvertedType(const nsACString& aFromType,
+                                  nsIChannel* aChannel, nsACString& aToType) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsIndexedToHTML::OnStartRequest(nsIRequest* request) {
+  nsCString buffer;
+  nsresult rv = DoOnStartRequest(request, buffer);
+  if (NS_FAILED(rv)) {
+    request->Cancel(rv);
+  }
+
+  rv = mListener->OnStartRequest(request);
+  if (NS_FAILED(rv)) return rv;
+
+  // The request may have been canceled, and if that happens, we want to
+  // suppress calls to OnDataAvailable.
+  request->GetStatus(&rv);
+  if (NS_FAILED(rv)) return rv;
+
+  // Push our buffer to the listener.
+
+  rv = SendToListener(request, buffer);
+  return rv;
+}
+
+nsresult nsIndexedToHTML::DoOnStartRequest(nsIRequest* request,
+                                           nsCString& aBuffer) {
+  nsresult rv;
+
+  nsCOMPtr<nsIChannel> channel = do_QueryInterface(request);
+  nsCOMPtr<nsIURI> uri;
+  rv = channel->GetOriginalURI(getter_AddRefs(uri));
+  if (NS_FAILED(rv)) return rv;
+
+  // We use the original URI for the title and parent link when it's a
+  // resource:// url, instead of the jar:file:// url it resolves to.
+  if (!uri->SchemeIs("resource")) {
+    rv = channel->GetURI(getter_AddRefs(uri));
+    if (NS_FAILED(rv)) return rv;
+  }
+
+  channel->SetContentType("text/html"_ns);
+
+  mParser = nsDirIndexParser::CreateInstance();
+  if (!mParser) return NS_ERROR_FAILURE;
+
+  rv = mParser->SetListener(this);
+  if (NS_FAILED(rv)) return rv;
+
+  rv = mParser->OnStartRequest(request);
+  if (NS_FAILED(rv)) return rv;
+
+  nsAutoCString baseUri, titleUri;
+  rv = uri->GetAsciiSpec(baseUri);
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsIURI> titleURL;
+  rv = NS_MutateURI(uri).SetQuery(""_ns).SetRef(""_ns).Finalize(titleURL);
+  if (NS_FAILED(rv)) {
+    titleURL = uri;
+  }
+
+  nsCString parentStr;
+
+  nsCString buffer;
+  buffer.AppendLiteral("<!DOCTYPE html>\n<html>\n<head>\n");
+
+  // XXX - should be using the 300: line from the parser.
+  // We can't guarantee that that comes before any entry, so we'd have to
+  // buffer, and do other painful stuff.
+  // I'll deal with this when I make the changes to handle welcome messages
+  // The .. stuff should also come from the lower level protocols, but that
+  // would muck up the XUL display
+  // - bbaetz
+
+  if (uri->SchemeIs("file")) {
+    nsCOMPtr<nsIFileURL> fileUrl = do_QueryInterface(uri);
+    nsCOMPtr<nsIFile> file;
+    rv = fileUrl->GetFile(getter_AddRefs(file));
+    if (NS_FAILED(rv)) return rv;
+
+    nsAutoCString url;
+    rv = net_GetURLSpecFromFile(file, url);
+    if (NS_FAILED(rv)) return rv;
+    baseUri.Assign(url);
+
+    nsCOMPtr<nsIFile> parent;
+    rv = file->GetParent(getter_AddRefs(parent));
+
+    if (parent && NS_SUCCEEDED(rv)) {
+      net_GetURLSpecFromDir(parent, url);
+      if (NS_FAILED(rv)) return rv;
+      parentStr.Assign(url);
+    }
+
+    // Directory index will be always encoded in UTF-8 if this is file url
+    buffer.AppendLiteral("<meta charset=\"UTF-8\">\n");
+
+  } else if (uri->SchemeIs("jar")) {
+    nsAutoCString path;
+    rv = uri->GetPathQueryRef(path);
+    if (NS_FAILED(rv)) return rv;
+
+    // a top-level jar directory URL is of the form jar:foo.zip!/
+    // path will be of the form foo.zip!/, and its last two characters
+    // will be "!/"
+    // XXX this won't work correctly when the name of the directory being
+    // XXX displayed ends with "!", but then again, jar: URIs don't deal
+    // XXX particularly well with such directories anyway
+    if (!StringEndsWith(path, "!/"_ns)) {
+      rv = uri->Resolve(".."_ns, parentStr);
+      if (NS_FAILED(rv)) return rv;
+    }
+  } else {
+    // default behavior for other protocols is to assume the channel's
+    // URL references a directory ending in '/' -- fixup if necessary.
+    nsAutoCString path;
+    rv = uri->GetPathQueryRef(path);
+    if (NS_FAILED(rv)) return rv;
+    if (baseUri.Last() != '/') {
+      baseUri.Append('/');
+      path.Append('/');
+      mozilla::Unused << NS_MutateURI(uri).SetPathQueryRef(path).Finalize(uri);
+    }
+    if (!path.EqualsLiteral("/")) {
+      rv = uri->Resolve(".."_ns, parentStr);
+      if (NS_FAILED(rv)) return rv;
+    }
+  }
+
+  rv = titleURL->GetAsciiSpec(titleUri);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  buffer.AppendLiteral(
+      "<style type=\"text/css\">\n"
+      ":root {\n"
+      "  font-family: sans-serif;\n"
+      "}\n"
+      "img {\n"
+      "  border: 0;\n"
+      "}\n"
+      "th {\n"
+      "  text-align: start;\n"
+      "  white-space: nowrap;\n"
+      "}\n"
+      "th > a {\n"
+      "  color: inherit;\n"
+      "}\n"
+      "table[order] > thead > tr > th {\n"
+      "  cursor: pointer;\n"
+      "}\n"
+      "table[order] > thead > tr > th::after {\n"
+      "  display: none;\n"
+      "  width: .8em;\n"
+      "  margin-inline-end: -.8em;\n"
+      "  text-align: end;\n"
+      "}\n"
+      "table[order=\"asc\"] > thead > tr > th::after {\n"
+      "  content: \"\\2193\"; /* DOWNWARDS ARROW (U+2193) */\n"
+      "}\n"
+      "table[order=\"desc\"] > thead > tr > th::after {\n"
+      "  content: \"\\2191\"; /* UPWARDS ARROW (U+2191) */\n"
+      "}\n"
+      "table[order][order-by=\"0\"] > thead > tr > th:first-child > a ,\n"
+      "table[order][order-by=\"1\"] > thead > tr > th:first-child + th > a ,\n"
+      "table[order][order-by=\"2\"] > thead > tr > th:first-child + th + th > "
+      "a {\n"
+      "  text-decoration: underline;\n"
+      "}\n"
+      "table[order][order-by=\"0\"] > thead > tr > th:first-child::after ,\n"
+      "table[order][order-by=\"1\"] > thead > tr > th:first-child + th::after "
+      ",\n"
+      "table[order][order-by=\"2\"] > thead > tr > th:first-child + th + "
+      "th::after {\n"
+      "  display: inline-block;\n"
+      "}\n"
+      "table.remove-hidden > tbody > tr.hidden-object {\n"
+      "  display: none;\n"
+      "}\n"
+      "td {\n"
+      "  white-space: nowrap;\n"
+      "}\n"
+      "table.ellipsis {\n"
+      "  width: 100%;\n"
+      "  table-layout: fixed;\n"
+      "  border-spacing: 0;\n"
+      "}\n"
+      "table.ellipsis > tbody > tr > td {\n"
+      "  overflow: hidden;\n"
+      "  text-overflow: ellipsis;\n"
+      "}\n"
+      "/* name */\n"
+      "/* name */\n"
+      "th:first-child {\n"
+      "  padding-inline-end: 2em;\n"
+      "}\n"
+      "/* size */\n"
+      "th:first-child + th {\n"
+      "  padding-inline-end: 1em;\n"
+      "}\n"
+      "td:first-child + td {\n"
+      "  text-align: end;\n"
+      "  padding-inline-end: 1em;\n"
+      "}\n"
+      "/* date */\n"
+      "td:first-child + td + td {\n"
+      "  padding-inline-start: 1em;\n"
+      "  padding-inline-end: .5em;\n"
+      "}\n"
+      "/* time */\n"
+      "td:first-child + td + td + td {\n"
+      "  padding-inline-start: .5em;\n"
+      "}\n"
+      ".symlink {\n"
+      "  font-style: italic;\n"
+      "}\n"
+      ".dir ,\n"
+      ".symlink ,\n"
+      ".file {\n"
+      "  margin-inline-start: 20px;\n"
+      "}\n"
+      ".dir::before ,\n"
+      ".file > img {\n"
+      "  margin-inline-end: 4px;\n"
+      "  margin-inline-start: -20px;\n"
+      "  max-width: 16px;\n"
+      "  max-height: 16px;\n"
+      "  vertical-align: middle;\n"
+      "}\n"
+      ".dir::before {\n"
+      "  content: url(resource://content-accessible/html/folder.png);\n"
+      "}\n"
+      "</style>\n"
+      "<link rel=\"stylesheet\" media=\"screen, projection\" type=\"text/css\""
+      " href=\"chrome://global/skin/dirListing/dirListing.css\">\n"
+      "<script type=\"application/javascript\">\n"
+      "'use strict';\n"
+      "var gTable, gOrderBy, gTBody, gRows, gUI_showHidden;\n"
+      "document.addEventListener(\"DOMContentLoaded\", function() {\n"
+      "  gTable = document.getElementsByTagName(\"table\")[0];\n"
+      "  gTBody = gTable.tBodies[0];\n"
+      "  if (gTBody.rows.length < 2)\n"
+      "    return;\n"
+      "  gUI_showHidden = document.getElementById(\"UI_showHidden\");\n"
+      "  var headCells = gTable.tHead.rows[0].cells,\n"
+      "      hiddenObjects = false;\n"
+      "  function rowAction(i) {\n"
+      "    return function(event) {\n"
+      "      event.preventDefault();\n"
+      "      orderBy(i);\n"
+      "    }\n"
+      "  }\n"
+      "  for (var i = headCells.length - 1; i >= 0; i--) {\n"
+      "    var anchor = document.createElement(\"a\");\n"
+      "    anchor.href = \"\";\n"
+      "    anchor.appendChild(headCells[i].firstChild);\n"
+      "    headCells[i].appendChild(anchor);\n"
+      "    headCells[i].addEventListener(\"click\", rowAction(i), true);\n"
+      "  }\n"
+      "  if (gUI_showHidden) {\n"
+      "    gRows = Array.from(gTBody.rows);\n"
+      "    hiddenObjects = gRows.some(row => row.className == "
+      "\"hidden-object\");\n"
+      "  }\n"
+      "  gTable.setAttribute(\"order\", \"\");\n"
+      "  if (hiddenObjects) {\n"
+      "    gUI_showHidden.style.display = \"block\";\n"
+      "    updateHidden();\n"
+      "  }\n"
+      "}, \"false\");\n"
+      "function compareRows(rowA, rowB) {\n"
+      "  var a = rowA.cells[gOrderBy].getAttribute(\"sortable-data\") || "
+      "\"\";\n"
+      "  var b = rowB.cells[gOrderBy].getAttribute(\"sortable-data\") || "
+      "\"\";\n"
+      "  var intA = +a;\n"
+      "  var intB = +b;\n"
+      "  if (a == intA && b == intB) {\n"
+      "    a = intA;\n"
+      "    b = intB;\n"
+      "  } else {\n"
+      "    a = a.toLowerCase();\n"
+      "    b = b.toLowerCase();\n"
+      "  }\n"
+      "  if (a < b)\n"
+      "    return -1;\n"
+      "  if (a > b)\n"
+      "    return 1;\n"
+      "  return 0;\n"
+      "}\n"
+      "function orderBy(column) {\n"
+      "  if (!gRows)\n"
+      "    gRows = Array.from(gTBody.rows);\n"
+      "  var order;\n"
+      "  if (gOrderBy == column) {\n"
+      "    order = gTable.getAttribute(\"order\") == \"asc\" ? \"desc\" : "
+      "\"asc\";\n"
+      "  } else {\n"
+      "    order = \"asc\";\n"
+      "    gOrderBy = column;\n"
+      "    gTable.setAttribute(\"order-by\", column);\n"
+      "    gRows.sort(compareRows);\n"
+      "  }\n"
+      "  gTable.removeChild(gTBody);\n"
+      "  gTable.setAttribute(\"order\", order);\n"
+      "  if (order == \"asc\")\n"
+      "    for (var i = 0; i < gRows.length; i++)\n"
+      "      gTBody.appendChild(gRows[i]);\n"
+      "  else\n"
+      "    for (var i = gRows.length - 1; i >= 0; i--)\n"
+      "      gTBody.appendChild(gRows[i]);\n"
+      "  gTable.appendChild(gTBody);\n"
+      "}\n"
+      "function updateHidden() {\n"
+      "  gTable.className = "
+      "gUI_showHidden.getElementsByTagName(\"input\")[0].checked ?\n"
+      "                     \"\" :\n"
+      "                     \"remove-hidden\";\n"
+      "}\n"
+      "</script>\n");
+
+  buffer.AppendLiteral(R"(<link rel="icon" type="image/png" href=")");
+  nsCOMPtr<nsIURI> innerUri = NS_GetInnermostURI(uri);
+  if (!innerUri) return NS_ERROR_UNEXPECTED;
+  nsCOMPtr<nsIFileURL> fileURL(do_QueryInterface(innerUri));
+  // XXX bug 388553: can't use skinnable icons here due to security restrictions
+  if (fileURL) {
+    buffer.AppendLiteral(
+        "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB"
+        "AAAAAQCAYAAAAf8%2F9hAAAAGXRFWHRTb2Z0d2FyZQBBZG9i"
+        "ZSBJbWFnZVJlYWR5ccllPAAAAjFJREFUeNqsU8uOElEQPffR"
+        "3XQ3ONASdBJCSBxHos5%2B3Bg3rvkCv8PElS78gPkO%2FATj"
+        "QoUdO2ftrJiRh6aneTb9sOpC4weMN6lcuFV16pxDIfI8x12O"
+        "YIDhcPiu2Wx%2B%2FHF5CW1Z6Jyegt%2FTNEWSJIjjGFEUIQ"
+        "xDrFYrWFSzXC4%2FdLvd95pRKpXKy%2BpRFZ7nwaWo1%2BsG"
+        "nQG2260BKJfLKJVKGI1GEEJw7ateryd0v993W63WEwjgxfn5"
+        "obGYzgCbzcaEbdsIggDj8Riu6z6iUk9SYZMSx8W0LMsM%2FS"
+        "KK75xnJlIq80anQXdbEp0OhcPJ0eiaJnGRMEyyPDsAKKUM9c"
+        "lkYoDo3SZJzzSdp0VSKYmfV1co%2Bz580kw5KDIM8RbRfEnU"
+        "f1HzxtQyMAGcaGruTKczMzEIaqhKifV6jd%2BzGQQB5llunF"
+        "%2FM52BizC2K5sYPYvZcu653tjOM9O93wnYc08gmkgg4VAxi"
+        "xfqFUJT36AYBZGd6PJkFCZnnlBxMp38gqIgLpZB0y4Nph18l"
+        "yWh5FFbrOSxbl3V4G%2BVB7T4ajYYxTyuLtO%2BCvWGgJE1M"
+        "c7JNsJEhvgw%2FQV4fo%2F24nbEsX2u1d5sVyn8sJO0ZAQiI"
+        "YnFh%2BxrfLz%2Fj29cBS%2FO14zg3i8XigW3ZkErDtmKoeM"
+        "%2BAJGRMnXeEPGKf0nCD1ydvkDzU9Jbc6OpR7WIw6L8lQ%2B"
+        "4pQ1%2FlPF0RGM9Ns91Wmptk0GfB4EJkt77vXYj%2F8m%2B8"
+        "y%2FkrwABHbz2H9V68DQAAAABJRU5ErkJggg%3D%3D");
+  } else {
+    buffer.AppendLiteral(
+        "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB"
+        "AAAAAQCAYAAAAf8%2F9hAAAAGXRFWHRTb2Z0d2FyZQBBZG9i"
+        "ZSBJbWFnZVJlYWR5ccllPAAAAeBJREFUeNqcU81O20AQ%2Ft"
+        "Z2AgQSYQRqL1UPVG2hAUQkxLEStz4DrXpLpD5Drz31Cajax%"
+        "2Bghhx6qHIJURBTxIwQRwopCBbZjHMcOTrzermPipsSt1Iw0"
+        "3p3ZmW%2B%2B2R0TxhgOD34wjCHZlQ0iDYz9yvEfhxMTCYhE"
+        "QDIZhkxKd2sqzX2TOD2vBQCQhpPefng1ZP2dVPlLLdpL8SEM"
+        "cxng%2Fbs0RIHhtgs4twxOh%2BHjZxvzDx%2F3GQQiDFISiR"
+        "BLFMPKTRMollzcWECrDVhtxtdRVsL9youPxGj%2FbdfFlUZh"
+        "tDyYbYqWRUdai1oQRZ5oHeHl2gNM%2B01Uqio8RlH%2Bnsaz"
+        "JzNwXcq1B%2BiXPHprlEEymeBfXs1w8XxxihfyuXqoHqpoGj"
+        "ZM04bddgG%2F9%2B8WGj87qDdsrK9m%2BoA%2BpbhQTDh2l1"
+        "%2Bi2weNbSHMZyjvNXmVbqh9Fj5Oz27uEoP%2BSTxANruJs9"
+        "L%2FT6P0ewqPx5nmiAG5f6AoCtN1PbJzuRyJAyDBzzSQYvEr"
+        "f06yYxhGXlEa8H2KVGoasjwLx3Ewk858opQWXm%2B%2Fib9E"
+        "QrBzclLLLy89xYvlpchvtixcX6uo1y%2FzsiwHrkIsgKbp%2"
+        "BYWFOWicuqppoNTnStHzPFCPQhBEBOyGAX4JMADFetubi4BS"
+        "YAAAAABJRU5ErkJggg%3D%3D");
+  }
+  buffer.AppendLiteral("\">\n<title>");
+
+  // Everything needs to end in a /,
+  // otherwise we end up linking to file:///foo/dirfile
+
+  if (!mTextToSubURI) {
+    mTextToSubURI = do_GetService(NS_ITEXTTOSUBURI_CONTRACTID, &rv);
+    if (NS_FAILED(rv)) return rv;
+  }
+
+  nsAutoString unEscapeSpec;
+  rv = mTextToSubURI->UnEscapeAndConvert("UTF-8"_ns, titleUri, unEscapeSpec);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  nsCString htmlEscSpecUtf8;
+  nsAppendEscapedHTML(NS_ConvertUTF16toUTF8(unEscapeSpec), htmlEscSpecUtf8);
+  AutoTArray<nsString, 1> formatTitle;
+  CopyUTF8toUTF16(htmlEscSpecUtf8, *formatTitle.AppendElement());
+
+  nsAutoString title;
+  rv = mBundle->FormatStringFromName("DirTitle", formatTitle, title);
+  if (NS_FAILED(rv)) return rv;
+
+  // we want to convert string bundle to NCR
+  // to ensure they're shown in any charsets
+  AppendNonAsciiToNCR(title, buffer);
+
+  buffer.AppendLiteral("</title>\n");
+
+  // If there is a quote character in the baseUri, then
+  // lets not add a base URL.  The reason for this is that
+  // if we stick baseUri containing a quote into a quoted
+  // string, the quote character will prematurely close
+  // the base href string.  This is a fall-back check;
+  // that's why it is OK to not use a base rather than
+  // trying to play nice and escaping the quotes.  See bug
+  // 358128.
+
+  if (!baseUri.Contains('"')) {
+    // Great, the baseUri does not contain a char that
+    // will prematurely close the string.  Go ahead an
+    // add a base href, but only do so if we're not
+    // dealing with a resource URI.
+    if (!uri->SchemeIs("resource")) {
+      buffer.AppendLiteral("<base href=\"");
+      nsAppendEscapedHTML(baseUri, buffer);
+      buffer.AppendLiteral("\" />\n");
+    }
+  } else {
+    NS_ERROR("broken protocol handler didn't escape double-quote.");
+  }
+
+  nsCString direction("ltr"_ns);
+  if (LocaleService::GetInstance()->IsAppLocaleRTL()) {
+    direction.AssignLiteral("rtl");
+  }
+
+  buffer.AppendLiteral("</head>\n<body dir=\"");
+  buffer.Append(direction);
+  buffer.AppendLiteral("\">\n<h1>");
+  AppendNonAsciiToNCR(title, buffer);
+  buffer.AppendLiteral("</h1>\n");
+
+  if (!parentStr.IsEmpty()) {
+    nsAutoString parentText;
+    rv = mBundle->GetStringFromName("DirGoUp", parentText);
+    if (NS_FAILED(rv)) return rv;
+
+    buffer.AppendLiteral(R"(<p id="UI_goUp"><a class="up" href=")");
+    nsAppendEscapedHTML(parentStr, buffer);
+    buffer.AppendLiteral("\">");
+    AppendNonAsciiToNCR(parentText, buffer);
+    buffer.AppendLiteral("</a></p>\n");
+  }
+
+  if (uri->SchemeIs("file")) {
+    nsAutoString showHiddenText;
+    rv = mBundle->GetStringFromName("ShowHidden", showHiddenText);
+    if (NS_FAILED(rv)) return rv;
+
+    buffer.AppendLiteral(
+        "<p id=\"UI_showHidden\" style=\"display:none\"><label><input "
+        "type=\"checkbox\" checked onchange=\"updateHidden()\">");
+    AppendNonAsciiToNCR(showHiddenText, buffer);
+    buffer.AppendLiteral("</label></p>\n");
+  }
+
+  buffer.AppendLiteral(
+      "<table>\n"
+      " <thead>\n"
+      "  <tr>\n"
+      "   <th>");
+
+  nsAutoString columnText;
+  rv = mBundle->GetStringFromName("DirColName", columnText);
+  if (NS_FAILED(rv)) return rv;
+  AppendNonAsciiToNCR(columnText, buffer);
+  buffer.AppendLiteral(
+      "</th>\n"
+      "   <th>");
+
+  rv = mBundle->GetStringFromName("DirColSize", columnText);
+  if (NS_FAILED(rv)) return rv;
+  AppendNonAsciiToNCR(columnText, buffer);
+  buffer.AppendLiteral(
+      "</th>\n"
+      "   <th colspan=\"2\">");
+
+  rv = mBundle->GetStringFromName("DirColMTime", columnText);
+  if (NS_FAILED(rv)) return rv;
+  AppendNonAsciiToNCR(columnText, buffer);
+  buffer.AppendLiteral(
+      "</th>\n"
+      "  </tr>\n"
+      " </thead>\n");
+  buffer.AppendLiteral(" <tbody>\n");
+
+  aBuffer = buffer;
+  return rv;
+}
+
+NS_IMETHODIMP
+nsIndexedToHTML::OnStopRequest(nsIRequest* request, nsresult aStatus) {
+  if (NS_SUCCEEDED(aStatus)) {
+    nsCString buffer;
+    buffer.AssignLiteral("</tbody></table></body></html>\n");
+
+    aStatus = SendToListener(request, buffer);
+  }
+
+  mParser->OnStopRequest(request, aStatus);
+  mParser = nullptr;
+
+  return mListener->OnStopRequest(request, aStatus);
+}
+
+nsresult nsIndexedToHTML::SendToListener(nsIRequest* aRequest,
+                                         const nsACString& aBuffer) {
+  nsCOMPtr<nsIInputStream> inputData;
+  nsresult rv = NS_NewCStringInputStream(getter_AddRefs(inputData), aBuffer);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return mListener->OnDataAvailable(aRequest, inputData, 0, aBuffer.Length());
+}
+
+NS_IMETHODIMP
+nsIndexedToHTML::OnDataAvailable(nsIRequest* aRequest, nsIInputStream* aInput,
+                                 uint64_t aOffset, uint32_t aCount) {
+  return mParser->OnDataAvailable(aRequest, aInput, aOffset, aCount);
+}
+
+NS_IMETHODIMP
+nsIndexedToHTML::OnDataFinished(nsresult aStatus) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsIndexedToHTML::CheckListenerChain() {
+  // nsIndexedToHTML does not support OnDataAvailable to run OMT. This class
+  // should only pass-through OnDataFinished notification.
+  return NS_ERROR_NO_INTERFACE;
+}
+
+static nsresult FormatTime(
+    const mozilla::intl::DateTimeFormat::StyleBag& aStyleBag,
+    const PRTime aPrTime, nsAString& aStringOut) {
+  // FormatPRExplodedTime will use GMT based formatted string (e.g. GMT+1)
+  // instead of local time zone name (e.g. CEST).
+  // To avoid this case when ResistFingerprinting is disabled, use
+  // |FormatPRTime| to show exact time zone name.
+  if (!nsContentUtils::ShouldResistFingerprinting(true,
+                                                  RFPTarget::JSDateTimeUTC)) {
+    return mozilla::intl::AppDateTimeFormat::Format(aStyleBag, aPrTime,
+                                                    aStringOut);
+  }
+
+  PRExplodedTime prExplodedTime;
+  PR_ExplodeTime(aPrTime, PR_GMTParameters, &prExplodedTime);
+  return mozilla::intl::AppDateTimeFormat::Format(aStyleBag, &prExplodedTime,
+                                                  aStringOut);
+}
+
+NS_IMETHODIMP
+nsIndexedToHTML::OnIndexAvailable(nsIRequest* aRequest, nsIDirIndex* aIndex) {
+  nsresult rv;
+  if (!aIndex) return NS_ERROR_NULL_POINTER;
+
+  nsCString pushBuffer;
+  pushBuffer.AppendLiteral("<tr");
+
+  // We don't know the file's character set yet, so retrieve the raw bytes
+  // which will be decoded by the HTML parser.
+  nsCString loc;
+  aIndex->GetLocation(loc);
+
+  // Adjust the length in case unescaping shortened the string.
+  loc.Truncate(nsUnescapeCount(loc.BeginWriting()));
+
+  if (loc.IsEmpty()) {
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+  if (loc.First() == char16_t('.')) {
+    pushBuffer.AppendLiteral(" class=\"hidden-object\"");
+  }
+
+  pushBuffer.AppendLiteral(">\n <td sortable-data=\"");
+
+  // The sort key is the name of the item, prepended by either 0, 1 or 2
+  // in order to group items.
+  uint32_t type;
+  aIndex->GetType(&type);
+  switch (type) {
+    case nsIDirIndex::TYPE_SYMLINK:
+      pushBuffer.Append('0');
+      break;
+    case nsIDirIndex::TYPE_DIRECTORY:
+      pushBuffer.Append('1');
+      break;
+    default:
+      pushBuffer.Append('2');
+      break;
+  }
+  nsCString escaped;
+  nsAppendEscapedHTML(loc, escaped);
+  pushBuffer.Append(escaped);
+
+  pushBuffer.AppendLiteral(
+      R"("><table class="ellipsis"><tbody><tr><td><a class=")");
+  switch (type) {
+    case nsIDirIndex::TYPE_DIRECTORY:
+      pushBuffer.AppendLiteral("dir");
+      break;
+    case nsIDirIndex::TYPE_SYMLINK:
+      pushBuffer.AppendLiteral("symlink");
+      break;
+    default:
+      pushBuffer.AppendLiteral("file");
+      break;
+  }
+
+  pushBuffer.AppendLiteral("\" href=\"");
+
+  // need to escape links
+  nsAutoCString locEscaped;
+
+  // Adding trailing slash helps to recognize whether the URL points to a file
+  // or a directory (bug #214405).
+  if ((type == nsIDirIndex::TYPE_DIRECTORY) && (loc.Last() != '/')) {
+    loc.Append('/');
+  }
+
+  // now minimally re-escape the location...
+  uint32_t escFlags;
+  // for some protocols, we expect the location to be absolute.
+  // if so, and if the location indeed appears to be a valid URI, then go
+  // ahead and treat it like one.
+
+  nsAutoCString scheme;
+  if (mExpectAbsLoc && NS_SUCCEEDED(net_ExtractURLScheme(loc, scheme))) {
+    // escape as absolute
+    escFlags = esc_Forced | esc_AlwaysCopy | esc_Minimal;
+  } else {
+    // escape as relative
+    // esc_Directory is needed because directories have a trailing slash.
+    // Without it, the trailing '/' will be escaped, and links from within
+    // that directory will be incorrect
+    escFlags = esc_Forced | esc_AlwaysCopy | esc_FileBaseName | esc_Colon |
+               esc_Directory;
+  }
+  NS_EscapeURL(loc.get(), loc.Length(), escFlags, locEscaped);
+  // esc_Directory does not escape the semicolons, so if a filename
+  // contains semicolons we need to manually escape them.
+  // This replacement should be removed in bug #473280
+  locEscaped.ReplaceSubstring(";", "%3b");
+  nsAppendEscapedHTML(locEscaped, pushBuffer);
+  pushBuffer.AppendLiteral("\">");
+
+  if (type == nsIDirIndex::TYPE_FILE || type == nsIDirIndex::TYPE_UNKNOWN) {
+    pushBuffer.AppendLiteral("<img src=\"moz-icon://");
+    int32_t lastDot = locEscaped.RFindChar('.');
+    if (lastDot != kNotFound) {
+      locEscaped.Cut(0, lastDot);
+      nsAppendEscapedHTML(locEscaped, pushBuffer);
+    } else {
+      pushBuffer.AppendLiteral("unknown");
+    }
+    pushBuffer.AppendLiteral("?size=16\" alt=\"");
+
+    nsAutoString altText;
+    rv = mBundle->GetStringFromName("DirFileLabel", altText);
+    if (NS_FAILED(rv)) return rv;
+    AppendNonAsciiToNCR(altText, pushBuffer);
+    pushBuffer.AppendLiteral("\">");
+  }
+
+  pushBuffer.Append(escaped);
+  pushBuffer.AppendLiteral("</a></td></tr></tbody></table></td>\n <td");
+
+  if (type == nsIDirIndex::TYPE_DIRECTORY ||
+      type == nsIDirIndex::TYPE_SYMLINK) {
+    pushBuffer.Append('>');
+  } else {
+    int64_t size;
+    aIndex->GetSize(&size);
+
+    if (uint64_t(size) != UINT64_MAX) {
+      pushBuffer.AppendLiteral(" sortable-data=\"");
+      pushBuffer.AppendInt(size);
+      pushBuffer.AppendLiteral("\">");
+      nsAutoCString sizeString;
+      FormatSizeString(size, sizeString);
+      pushBuffer.Append(sizeString);
+    } else {
+      pushBuffer.Append('>');
+    }
+  }
+  pushBuffer.AppendLiteral("</td>\n <td");
+
+  PRTime t;
+  aIndex->GetLastModified(&t);
+
+  if (t == -1LL) {
+    pushBuffer.AppendLiteral("></td>\n <td>");
+  } else {
+    pushBuffer.AppendLiteral(" sortable-data=\"");
+    pushBuffer.AppendInt(static_cast<int64_t>(t));
+    pushBuffer.AppendLiteral("\">");
+    // Add date string
+    nsAutoString formatted;
+    mozilla::intl::DateTimeFormat::StyleBag dateBag;
+    dateBag.date = Some(mozilla::intl::DateTimeFormat::Style::Short);
+    FormatTime(dateBag, t, formatted);
+    AppendNonAsciiToNCR(formatted, pushBuffer);
+    pushBuffer.AppendLiteral("</td>\n <td>");
+    // Add time string
+    mozilla::intl::DateTimeFormat::StyleBag timeBag;
+    timeBag.time = Some(mozilla::intl::DateTimeFormat::Style::Long);
+    FormatTime(timeBag, t, formatted);
+    // use NCR to show date in any doc charset
+    AppendNonAsciiToNCR(formatted, pushBuffer);
+  }
+
+  pushBuffer.AppendLiteral("</td>\n</tr>");
+
+  return SendToListener(aRequest, pushBuffer);
+}
+
+void nsIndexedToHTML::FormatSizeString(int64_t inSize,
+                                       nsCString& outSizeString) {
+  outSizeString.Truncate();
+  if (inSize > int64_t(0)) {
+    // round up to the nearest Kilobyte
+    int64_t upperSize = (inSize + int64_t(1023)) / int64_t(1024);
+    outSizeString.AppendInt(upperSize);
+    outSizeString.AppendLiteral(" KB");
+  }
+}
diff --git a/netwerk/streamconv/converters/nsIndexedToHTML.h b/netwerk/streamconv/converters/nsIndexedToHTML.h
new file mode 100644
index 0000000000..736df3ebf7
--- /dev/null
+++ b/netwerk/streamconv/converters/nsIndexedToHTML.h
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 4; 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 ____nsindexedtohtml___h___
+#define ____nsindexedtohtml___h___
+
+#include "nsCOMPtr.h"
+#include "nsIThreadRetargetableStreamListener.h"
+#include "nsString.h"
+#include "nsIStreamConverter.h"
+#include "nsIDirIndexListener.h"
+
+#define NS_NSINDEXEDTOHTMLCONVERTER_CID              \
+  {                                                  \
+    0xcf0f71fd, 0xfafd, 0x4e2b, {                    \
+      0x9f, 0xdc, 0x13, 0x4d, 0x97, 0x2e, 0x16, 0xe2 \
+    }                                                \
+  }
+
+class nsIStringBundle;
+class nsITextToSubURI;
+
+class nsIndexedToHTML : public nsIStreamConverter, public nsIDirIndexListener {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISTREAMCONVERTER
+  NS_DECL_NSIREQUESTOBSERVER
+  NS_DECL_NSISTREAMLISTENER
+  NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER
+  NS_DECL_NSIDIRINDEXLISTENER
+
+  nsIndexedToHTML() = default;
+
+  nsresult Init(nsIStreamListener* aListener);
+
+  static nsresult Create(REFNSIID aIID, void** aResult);
+
+ protected:
+  void FormatSizeString(int64_t inSize, nsCString& outSizeString);
+  nsresult SendToListener(nsIRequest* aRequest, const nsACString& aBuffer);
+  // Helper to properly implement OnStartRequest
+  nsresult DoOnStartRequest(nsIRequest* request, nsCString& aBuffer);
+
+ protected:
+  nsCOMPtr<nsIDirIndexParser> mParser;
+  nsCOMPtr<nsIStreamListener> mListener;  // final listener (consumer)
+
+  nsCOMPtr<nsIStringBundle> mBundle;
+
+  nsCOMPtr<nsITextToSubURI> mTextToSubURI;
+
+ private:
+  // Expecting absolute locations, given by 201 lines.
+  bool mExpectAbsLoc{false};
+
+  virtual ~nsIndexedToHTML() = default;
+};
+
+#endif
diff --git a/netwerk/streamconv/converters/nsMultiMixedConv.cpp b/netwerk/streamconv/converters/nsMultiMixedConv.cpp
new file mode 100644
index 0000000000..fb21d6673f
--- /dev/null
+++ b/netwerk/streamconv/converters/nsMultiMixedConv.cpp
@@ -0,0 +1,1051 @@
+/* -*- 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 "nsMultiMixedConv.h"
+#include "nsIHttpChannel.h"
+#include "nsIThreadRetargetableStreamListener.h"
+#include "nsNetCID.h"
+#include "nsMimeTypes.h"
+#include "nsIStringStream.h"
+#include "nsCRT.h"
+#include "nsIHttpChannelInternal.h"
+#include "nsURLHelper.h"
+#include "nsIStreamConverterService.h"
+#include <algorithm>
+#include "nsContentSecurityManager.h"
+#include "nsHttp.h"
+#include "nsNetUtil.h"
+#include "nsIURI.h"
+#include "nsHttpHeaderArray.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/Tokenizer.h"
+#include "nsComponentManagerUtils.h"
+#include "mozilla/StaticPrefs_network.h"
+
+using namespace mozilla;
+
+nsPartChannel::nsPartChannel(nsIChannel* aMultipartChannel, uint32_t aPartID,
+                             bool aIsFirstPart, nsIStreamListener* aListener)
+    : mMultipartChannel(aMultipartChannel),
+      mListener(aListener),
+      mPartID(aPartID),
+      mIsFirstPart(aIsFirstPart) {
+  // Inherit the load flags from the original channel...
+  mMultipartChannel->GetLoadFlags(&mLoadFlags);
+
+  mMultipartChannel->GetLoadGroup(getter_AddRefs(mLoadGroup));
+}
+
+void nsPartChannel::InitializeByteRange(int64_t aStart, int64_t aEnd) {
+  mIsByteRangeRequest = true;
+
+  mByteRangeStart = aStart;
+  mByteRangeEnd = aEnd;
+}
+
+nsresult nsPartChannel::SendOnStartRequest(nsISupports* aContext) {
+  return mListener->OnStartRequest(this);
+}
+
+nsresult nsPartChannel::SendOnDataAvailable(nsISupports* aContext,
+                                            nsIInputStream* aStream,
+                                            uint64_t aOffset, uint32_t aLen) {
+  return mListener->OnDataAvailable(this, aStream, aOffset, aLen);
+}
+
+nsresult nsPartChannel::SendOnStopRequest(nsISupports* aContext,
+                                          nsresult aStatus) {
+  // Drop the listener
+  nsCOMPtr<nsIStreamListener> listener;
+  listener.swap(mListener);
+  return listener->OnStopRequest(this, aStatus);
+}
+
+void nsPartChannel::SetContentDisposition(
+    const nsACString& aContentDispositionHeader) {
+  mContentDispositionHeader = aContentDispositionHeader;
+  nsCOMPtr<nsIURI> uri;
+  GetURI(getter_AddRefs(uri));
+  NS_GetFilenameFromDisposition(mContentDispositionFilename,
+                                mContentDispositionHeader);
+  mContentDisposition =
+      NS_GetContentDispositionFromHeader(mContentDispositionHeader, this);
+}
+
+//
+// nsISupports implementation...
+//
+
+NS_IMPL_ADDREF(nsPartChannel)
+NS_IMPL_RELEASE(nsPartChannel)
+
+NS_INTERFACE_MAP_BEGIN(nsPartChannel)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIChannel)
+  NS_INTERFACE_MAP_ENTRY(nsIRequest)
+  NS_INTERFACE_MAP_ENTRY(nsIChannel)
+  NS_INTERFACE_MAP_ENTRY(nsIByteRangeRequest)
+  NS_INTERFACE_MAP_ENTRY(nsIMultiPartChannel)
+NS_INTERFACE_MAP_END
+
+//
+// nsIRequest implementation...
+//
+
+NS_IMETHODIMP
+nsPartChannel::GetName(nsACString& aResult) {
+  return mMultipartChannel->GetName(aResult);
+}
+
+NS_IMETHODIMP
+nsPartChannel::IsPending(bool* aResult) {
+  // For now, consider the active lifetime of each part the same as
+  // the underlying multipart channel...  This is not exactly right,
+  // but it is good enough :-)
+  return mMultipartChannel->IsPending(aResult);
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetStatus(nsresult* aResult) {
+  nsresult rv = NS_OK;
+
+  if (NS_FAILED(mStatus)) {
+    *aResult = mStatus;
+  } else {
+    rv = mMultipartChannel->GetStatus(aResult);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP nsPartChannel::SetCanceledReason(const nsACString& aReason) {
+  return SetCanceledReasonImpl(aReason);
+}
+
+NS_IMETHODIMP nsPartChannel::GetCanceledReason(nsACString& aReason) {
+  return GetCanceledReasonImpl(aReason);
+}
+
+NS_IMETHODIMP nsPartChannel::CancelWithReason(nsresult aStatus,
+                                              const nsACString& aReason) {
+  return CancelWithReasonImpl(aStatus, aReason);
+}
+
+NS_IMETHODIMP
+nsPartChannel::Cancel(nsresult aStatus) {
+  // Cancelling an individual part must not cancel the underlying
+  // multipart channel...
+  // XXX but we should stop sending data for _this_ part channel!
+  mStatus = aStatus;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetCanceled(bool* aCanceled) {
+  *aCanceled = NS_FAILED(mStatus);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::Suspend(void) {
+  // Suspending an individual part must not suspend the underlying
+  // multipart channel...
+  // XXX why not?
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::Resume(void) {
+  // Resuming an individual part must not resume the underlying
+  // multipart channel...
+  // XXX why not?
+  return NS_OK;
+}
+
+//
+// nsIChannel implementation
+//
+
+NS_IMETHODIMP
+nsPartChannel::GetOriginalURI(nsIURI** aURI) {
+  return mMultipartChannel->GetOriginalURI(aURI);
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetOriginalURI(nsIURI* aURI) {
+  return mMultipartChannel->SetOriginalURI(aURI);
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetURI(nsIURI** aURI) { return mMultipartChannel->GetURI(aURI); }
+
+NS_IMETHODIMP
+nsPartChannel::Open(nsIInputStream** aStream) {
+  nsCOMPtr<nsIStreamListener> listener;
+  nsresult rv =
+      nsContentSecurityManager::doContentSecurityCheck(this, listener);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // This channel cannot be opened!
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsPartChannel::AsyncOpen(nsIStreamListener* aListener) {
+  nsCOMPtr<nsIStreamListener> listener = aListener;
+  nsresult rv =
+      nsContentSecurityManager::doContentSecurityCheck(this, listener);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // This channel cannot be opened!
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetLoadFlags(nsLoadFlags* aLoadFlags) {
+  *aLoadFlags = mLoadFlags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetLoadFlags(nsLoadFlags aLoadFlags) {
+  mLoadFlags = aLoadFlags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetTRRMode(nsIRequest::TRRMode* aTRRMode) {
+  return GetTRRModeImpl(aTRRMode);
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetTRRMode(nsIRequest::TRRMode aTRRMode) {
+  return SetTRRModeImpl(aTRRMode);
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetIsDocument(bool* aIsDocument) {
+  return NS_GetIsDocumentChannel(this, aIsDocument);
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetLoadGroup(nsILoadGroup** aLoadGroup) {
+  *aLoadGroup = do_AddRef(mLoadGroup).take();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetLoadGroup(nsILoadGroup* aLoadGroup) {
+  mLoadGroup = aLoadGroup;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetOwner(nsISupports** aOwner) {
+  return mMultipartChannel->GetOwner(aOwner);
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetOwner(nsISupports* aOwner) {
+  return mMultipartChannel->SetOwner(aOwner);
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetLoadInfo(nsILoadInfo** aLoadInfo) {
+  return mMultipartChannel->GetLoadInfo(aLoadInfo);
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetLoadInfo(nsILoadInfo* aLoadInfo) {
+  MOZ_RELEASE_ASSERT(aLoadInfo, "loadinfo can't be null");
+  return mMultipartChannel->SetLoadInfo(aLoadInfo);
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetNotificationCallbacks(nsIInterfaceRequestor** aCallbacks) {
+  return mMultipartChannel->GetNotificationCallbacks(aCallbacks);
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetNotificationCallbacks(nsIInterfaceRequestor* aCallbacks) {
+  return mMultipartChannel->SetNotificationCallbacks(aCallbacks);
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetSecurityInfo(nsITransportSecurityInfo** aSecurityInfo) {
+  return mMultipartChannel->GetSecurityInfo(aSecurityInfo);
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetContentType(nsACString& aContentType) {
+  aContentType = mContentType;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetContentType(const nsACString& aContentType) {
+  bool dummy;
+  net_ParseContentType(aContentType, mContentType, mContentCharset, &dummy);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetContentCharset(nsACString& aContentCharset) {
+  aContentCharset = mContentCharset;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetContentCharset(const nsACString& aContentCharset) {
+  mContentCharset = aContentCharset;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetContentLength(int64_t* aContentLength) {
+  *aContentLength = mContentLength;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetContentLength(int64_t aContentLength) {
+  mContentLength = aContentLength;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetContentDisposition(uint32_t* aContentDisposition) {
+  if (mContentDispositionHeader.IsEmpty()) return NS_ERROR_NOT_AVAILABLE;
+
+  *aContentDisposition = mContentDisposition;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetContentDisposition(uint32_t aContentDisposition) {
+  return NS_ERROR_NOT_AVAILABLE;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetContentDispositionFilename(
+    nsAString& aContentDispositionFilename) {
+  if (mContentDispositionFilename.IsEmpty()) return NS_ERROR_NOT_AVAILABLE;
+
+  aContentDispositionFilename = mContentDispositionFilename;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::SetContentDispositionFilename(
+    const nsAString& aContentDispositionFilename) {
+  return NS_ERROR_NOT_AVAILABLE;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetContentDispositionHeader(
+    nsACString& aContentDispositionHeader) {
+  if (mContentDispositionHeader.IsEmpty()) return NS_ERROR_NOT_AVAILABLE;
+
+  aContentDispositionHeader = mContentDispositionHeader;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetPartID(uint32_t* aPartID) {
+  *aPartID = mPartID;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetIsFirstPart(bool* aIsFirstPart) {
+  *aIsFirstPart = mIsFirstPart;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetIsLastPart(bool* aIsLastPart) {
+  *aIsLastPart = mIsLastPart;
+  return NS_OK;
+}
+
+//
+// nsIByteRangeRequest implementation...
+//
+
+NS_IMETHODIMP
+nsPartChannel::GetIsByteRangeRequest(bool* aIsByteRangeRequest) {
+  *aIsByteRangeRequest = mIsByteRangeRequest;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetStartRange(int64_t* aStartRange) {
+  *aStartRange = mByteRangeStart;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetEndRange(int64_t* aEndRange) {
+  *aEndRange = mByteRangeEnd;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPartChannel::GetBaseChannel(nsIChannel** aReturn) {
+  NS_ENSURE_ARG_POINTER(aReturn);
+
+  *aReturn = do_AddRef(mMultipartChannel).take();
+  return NS_OK;
+}
+
+// nsISupports implementation
+NS_IMPL_ISUPPORTS(nsMultiMixedConv, nsIStreamConverter, nsIStreamListener,
+                  nsIThreadRetargetableStreamListener, nsIRequestObserver)
+
+// nsIStreamConverter implementation
+
+// No syncronous conversion at this time.
+NS_IMETHODIMP
+nsMultiMixedConv::Convert(nsIInputStream* aFromStream, const char* aFromType,
+                          const char* aToType, nsISupports* aCtxt,
+                          nsIInputStream** _retval) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+// Stream converter service calls this to initialize the actual stream converter
+// (us).
+NS_IMETHODIMP
+nsMultiMixedConv::AsyncConvertData(const char* aFromType, const char* aToType,
+                                   nsIStreamListener* aListener,
+                                   nsISupports* aCtxt) {
+  NS_ASSERTION(aListener && aFromType && aToType,
+               "null pointer passed into multi mixed converter");
+
+  // hook up our final listener. this guy gets the various On*() calls we want
+  // to throw at him.
+  //
+  // WARNING: this listener must be able to handle multiple OnStartRequest,
+  // OnDataAvail() and OnStopRequest() call combinations. We call of series
+  // of these for each sub-part in the raw stream.
+  mFinalListener = aListener;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMultiMixedConv::GetConvertedType(const nsACString& aFromType,
+                                   nsIChannel* aChannel, nsACString& aToType) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+// nsIRequestObserver implementation
+NS_IMETHODIMP
+nsMultiMixedConv::OnStartRequest(nsIRequest* request) {
+  // we're assuming the content-type is available at this stage
+  NS_ASSERTION(mBoundary.IsEmpty(), "a second on start???");
+
+  nsresult rv;
+
+  mTotalSent = 0;
+  mChannel = do_QueryInterface(request, &rv);
+  if (NS_FAILED(rv)) return rv;
+
+  nsAutoCString contentType;
+
+  // ask the HTTP channel for the content-type and extract the boundary from it.
+  nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(mChannel, &rv);
+  if (NS_SUCCEEDED(rv)) {
+    rv = httpChannel->GetResponseHeader("content-type"_ns, contentType);
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+    nsCString csp;
+    rv = httpChannel->GetResponseHeader("content-security-policy"_ns, csp);
+    if (NS_SUCCEEDED(rv)) {
+      mRootContentSecurityPolicy = csp;
+    }
+  } else {
+    // try asking the channel directly
+    rv = mChannel->GetContentType(contentType);
+    if (NS_FAILED(rv)) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  Tokenizer p(contentType);
+  p.SkipUntil(Token::Char(';'));
+  if (!p.CheckChar(';')) {
+    return NS_ERROR_CORRUPTED_CONTENT;
+  }
+  p.SkipWhites();
+  if (!p.CheckWord("boundary")) {
+    return NS_ERROR_CORRUPTED_CONTENT;
+  }
+  p.SkipWhites();
+  if (!p.CheckChar('=')) {
+    return NS_ERROR_CORRUPTED_CONTENT;
+  }
+  p.SkipWhites();
+  Unused << p.ReadUntil(Token::Char(';'), mBoundary);
+  mBoundary.Trim(
+      " \"");  // ignoring potential quoted string formatting violations
+  if (mBoundary.IsEmpty()) {
+    return NS_ERROR_CORRUPTED_CONTENT;
+  }
+
+  mHeaderTokens[HEADER_CONTENT_TYPE] = mTokenizer.AddCustomToken(
+      "content-type", mTokenizer.CASE_INSENSITIVE, false);
+  mHeaderTokens[HEADER_CONTENT_LENGTH] = mTokenizer.AddCustomToken(
+      "content-length", mTokenizer.CASE_INSENSITIVE, false);
+  mHeaderTokens[HEADER_CONTENT_DISPOSITION] = mTokenizer.AddCustomToken(
+      "content-disposition", mTokenizer.CASE_INSENSITIVE, false);
+  mHeaderTokens[HEADER_SET_COOKIE] = mTokenizer.AddCustomToken(
+      "set-cookie", mTokenizer.CASE_INSENSITIVE, false);
+  mHeaderTokens[HEADER_CONTENT_RANGE] = mTokenizer.AddCustomToken(
+      "content-range", mTokenizer.CASE_INSENSITIVE, false);
+  mHeaderTokens[HEADER_RANGE] =
+      mTokenizer.AddCustomToken("range", mTokenizer.CASE_INSENSITIVE, false);
+  mHeaderTokens[HEADER_CONTENT_SECURITY_POLICY] = mTokenizer.AddCustomToken(
+      "content-security-policy", mTokenizer.CASE_INSENSITIVE, false);
+
+  mLFToken = mTokenizer.AddCustomToken("\n", mTokenizer.CASE_SENSITIVE, false);
+  mCRLFToken =
+      mTokenizer.AddCustomToken("\r\n", mTokenizer.CASE_SENSITIVE, false);
+
+  SwitchToControlParsing();
+
+  mBoundaryToken =
+      mTokenizer.AddCustomToken(mBoundary, mTokenizer.CASE_SENSITIVE);
+  mBoundaryTokenWithDashes =
+      mTokenizer.AddCustomToken("--"_ns + mBoundary, mTokenizer.CASE_SENSITIVE);
+
+  return NS_OK;
+}
+
+// nsIStreamListener implementation
+NS_IMETHODIMP
+nsMultiMixedConv::OnDataAvailable(nsIRequest* request, nsIInputStream* inStr,
+                                  uint64_t sourceOffset, uint32_t count) {
+  // Failing these assertions may indicate that some of the target listeners of
+  // this converter is looping the thead queue, which is harmful to how we
+  // collect the raw (content) data.
+  MOZ_DIAGNOSTIC_ASSERT(!mInOnDataAvailable,
+                        "nsMultiMixedConv::OnDataAvailable reentered!");
+  MOZ_DIAGNOSTIC_ASSERT(
+      !mRawData, "There are unsent data from the previous tokenizer feed!");
+
+  if (mInOnDataAvailable) {
+    // The multipart logic is incapable of being reentered.
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  mozilla::AutoRestore<bool> restore(mInOnDataAvailable);
+  mInOnDataAvailable = true;
+
+  nsresult rv_feed = mTokenizer.FeedInput(inStr, count);
+  // We must do this every time.  Regardless if something has failed during the
+  // parsing process.  Otherwise the raw data reference would not be thrown
+  // away.
+  nsresult rv_send = SendData();
+
+  return NS_FAILED(rv_send) ? rv_send : rv_feed;
+}
+
+NS_IMETHODIMP
+nsMultiMixedConv::OnDataFinished(nsresult aStatus) { return NS_OK; }
+
+NS_IMETHODIMP
+nsMultiMixedConv::CheckListenerChain() { return NS_ERROR_NOT_IMPLEMENTED; }
+
+NS_IMETHODIMP
+nsMultiMixedConv::OnStopRequest(nsIRequest* request, nsresult aStatus) {
+  nsresult rv;
+
+  if (mPartChannel) {
+    mPartChannel->SetIsLastPart();
+
+    MOZ_DIAGNOSTIC_ASSERT(
+        !mRawData, "There are unsent data from the previous tokenizer feed!");
+
+    rv = mTokenizer.FinishInput();
+    if (NS_SUCCEEDED(aStatus)) {
+      aStatus = rv;
+    }
+    rv = SendData();
+    if (NS_SUCCEEDED(aStatus)) {
+      aStatus = rv;
+    }
+
+    (void)SendStop(aStatus);
+  } else if (NS_FAILED(aStatus) && !mRequestListenerNotified) {
+    // underlying data production problem. we should not be in
+    // the middle of sending data. if we were, mPartChannel,
+    // above, would have been non-null.
+
+    (void)mFinalListener->OnStartRequest(request);
+    (void)mFinalListener->OnStopRequest(request, aStatus);
+  }
+
+  nsCOMPtr<nsIMultiPartChannelListener> multiListener =
+      do_QueryInterface(mFinalListener);
+  if (multiListener) {
+    multiListener->OnAfterLastPart(aStatus);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsMultiMixedConv::ConsumeToken(Token const& token) {
+  nsresult rv;
+
+  switch (mParserState) {
+    case PREAMBLE:
+      if (token.Equals(mBoundaryTokenWithDashes)) {
+        // The server first used boundary '--boundary'.  Hence, we no longer
+        // accept plain 'boundary' token as a delimiter.
+        mTokenizer.RemoveCustomToken(mBoundaryToken);
+        mParserState = BOUNDARY_CRLF;
+        break;
+      }
+      if (token.Equals(mBoundaryToken)) {
+        // And here the opposite from the just above block...
+        mTokenizer.RemoveCustomToken(mBoundaryTokenWithDashes);
+        mParserState = BOUNDARY_CRLF;
+        break;
+      }
+
+      // This is a preamble, just ignore it and wait for the boundary.
+      break;
+
+    case BOUNDARY_CRLF:
+      if (token.Equals(Token::NewLine())) {
+        mParserState = HEADER_NAME;
+        mResponseHeader = HEADER_UNKNOWN;
+        HeadersToDefault();
+        SetHeaderTokensEnabled(true);
+        break;
+      }
+      return NS_ERROR_CORRUPTED_CONTENT;
+
+    case HEADER_NAME:
+      SetHeaderTokensEnabled(false);
+      if (token.Equals(Token::NewLine())) {
+        mParserState = BODY_INIT;
+        SwitchToBodyParsing();
+        break;
+      }
+      for (uint32_t h = HEADER_CONTENT_TYPE; h < HEADER_UNKNOWN; ++h) {
+        if (token.Equals(mHeaderTokens[h])) {
+          mResponseHeader = static_cast<EHeader>(h);
+          break;
+        }
+      }
+      mParserState = HEADER_SEP;
+      break;
+
+    case HEADER_SEP:
+      if (token.Equals(Token::Char(':'))) {
+        mParserState = HEADER_VALUE;
+        mResponseHeaderValue.Truncate();
+        break;
+      }
+      if (mResponseHeader == HEADER_UNKNOWN) {
+        // If the header is not of any we understand, just pass everything till
+        // ':'
+        break;
+      }
+      if (token.Equals(Token::Whitespace())) {
+        // Accept only header-name traling whitespaces after known headers
+        break;
+      }
+      return NS_ERROR_CORRUPTED_CONTENT;
+
+    case HEADER_VALUE:
+      if (token.Equals(Token::Whitespace()) && mResponseHeaderValue.IsEmpty()) {
+        // Eat leading whitespaces
+        break;
+      }
+      if (token.Equals(Token::NewLine())) {
+        nsresult rv = ProcessHeader();
+        if (NS_FAILED(rv)) {
+          return rv;
+        }
+        mParserState = HEADER_NAME;
+        mResponseHeader = HEADER_UNKNOWN;
+        SetHeaderTokensEnabled(true);
+      } else {
+        mResponseHeaderValue.Append(token.Fragment());
+      }
+      break;
+
+    case BODY_INIT:
+      rv = SendStart();
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+      mParserState = BODY;
+      [[fallthrough]];
+
+    case BODY: {
+      if (!token.Equals(mLFToken) && !token.Equals(mCRLFToken)) {
+        if (token.Equals(mBoundaryTokenWithDashes) ||
+            token.Equals(mBoundaryToken)) {
+          // Allow CRLF to NOT be part of the boundary as well
+          SwitchToControlParsing();
+          mParserState = TRAIL_DASH1;
+          break;
+        }
+        AccumulateData(token);
+        break;
+      }
+
+      // After CRLF we must explicitly check for boundary.  If found,
+      // that CRLF is part of the boundary and must not be send to the
+      // data listener.
+      Token token2;
+      if (!mTokenizer.Next(token2)) {
+        // Note: this will give us the CRLF token again when more data
+        // or OnStopRequest arrive.  I.e. we will enter BODY case in
+        // the very same state as we are now and start this block over.
+        mTokenizer.NeedMoreInput();
+        break;
+      }
+      if (token2.Equals(mBoundaryTokenWithDashes) ||
+          token2.Equals(mBoundaryToken)) {
+        SwitchToControlParsing();
+        mParserState = TRAIL_DASH1;
+        break;
+      }
+
+      AccumulateData(token);
+      AccumulateData(token2);
+      break;
+    }
+
+    case TRAIL_DASH1:
+      if (token.Equals(Token::NewLine())) {
+        rv = SendStop(NS_OK);
+        if (NS_FAILED(rv)) {
+          return rv;
+        }
+        mParserState = BOUNDARY_CRLF;
+        mTokenizer.Rollback();
+        break;
+      }
+      if (token.Equals(Token::Char('-'))) {
+        mParserState = TRAIL_DASH2;
+        break;
+      }
+      return NS_ERROR_CORRUPTED_CONTENT;
+
+    case TRAIL_DASH2:
+      if (token.Equals(Token::Char('-'))) {
+        mPartChannel->SetIsLastPart();
+        // SendStop calls SendData first.
+        rv = SendStop(NS_OK);
+        if (NS_FAILED(rv)) {
+          return rv;
+        }
+        mParserState = EPILOGUE;
+        break;
+      }
+      return NS_ERROR_CORRUPTED_CONTENT;
+
+    case EPILOGUE:
+      // Just ignore
+      break;
+
+    default:
+      MOZ_ASSERT(false, "Missing parser state handling branch");
+      break;
+  }  // switch
+
+  return NS_OK;
+}
+
+void nsMultiMixedConv::SetHeaderTokensEnabled(bool aEnable) {
+  for (uint32_t h = HEADER_FIRST; h < HEADER_UNKNOWN; ++h) {
+    mTokenizer.EnableCustomToken(mHeaderTokens[h], aEnable);
+  }
+}
+
+void nsMultiMixedConv::SwitchToBodyParsing() {
+  mTokenizer.SetTokenizingMode(Tokenizer::Mode::CUSTOM_ONLY);
+  mTokenizer.EnableCustomToken(mLFToken, true);
+  mTokenizer.EnableCustomToken(mCRLFToken, true);
+  mTokenizer.EnableCustomToken(mBoundaryTokenWithDashes, true);
+  mTokenizer.EnableCustomToken(mBoundaryToken, true);
+}
+
+void nsMultiMixedConv::SwitchToControlParsing() {
+  mTokenizer.SetTokenizingMode(Tokenizer::Mode::FULL);
+  mTokenizer.EnableCustomToken(mLFToken, false);
+  mTokenizer.EnableCustomToken(mCRLFToken, false);
+  mTokenizer.EnableCustomToken(mBoundaryTokenWithDashes, false);
+  mTokenizer.EnableCustomToken(mBoundaryToken, false);
+}
+
+// nsMultiMixedConv methods
+nsMultiMixedConv::nsMultiMixedConv()
+    // XXX: This is a hack to bypass the raw pointer to refcounted object in
+    // lambda analysis. It should be removed and replaced when the
+    // IncrementalTokenizer API is improved to avoid the need for such
+    // workarounds.
+    //
+    // This is safe because `mTokenizer` will not outlive `this`, meaning
+    // that this std::bind object will be destroyed before `this` dies.
+    : mTokenizer(std::bind(&nsMultiMixedConv::ConsumeToken, this,
+                           std::placeholders::_1)) {}
+
+nsresult nsMultiMixedConv::SendStart() {
+  nsresult rv = NS_OK;
+
+  nsCOMPtr<nsIStreamListener> partListener(mFinalListener);
+  if (mContentType.IsEmpty()) {
+    mContentType.AssignLiteral(UNKNOWN_CONTENT_TYPE);
+    nsCOMPtr<nsIStreamConverterService> serv =
+        do_GetService(NS_STREAMCONVERTERSERVICE_CONTRACTID, &rv);
+    if (NS_SUCCEEDED(rv)) {
+      nsCOMPtr<nsIStreamListener> converter;
+      rv = serv->AsyncConvertData(UNKNOWN_CONTENT_TYPE, "*/*", mFinalListener,
+                                  mContext, getter_AddRefs(converter));
+      if (NS_SUCCEEDED(rv)) {
+        partListener = converter;
+      }
+    }
+  }
+
+  // if we already have an mPartChannel, that means we never sent a Stop()
+  // before starting up another "part." that would be bad.
+  MOZ_ASSERT(!mPartChannel, "tisk tisk, shouldn't be overwriting a channel");
+
+  nsPartChannel* newChannel;
+  newChannel = new nsPartChannel(mChannel, mCurrentPartID, mCurrentPartID == 0,
+                                 partListener);
+
+  ++mCurrentPartID;
+
+  if (mIsByteRangeRequest) {
+    newChannel->InitializeByteRange(mByteRangeStart, mByteRangeEnd);
+  }
+
+  mTotalSent = 0;
+
+  // Set up the new part channel...
+  mPartChannel = newChannel;
+
+  rv = mPartChannel->SetContentType(mContentType);
+  if (NS_FAILED(rv)) return rv;
+
+  rv = mPartChannel->SetContentLength(mContentLength);
+  if (NS_FAILED(rv)) return rv;
+
+  mPartChannel->SetContentDisposition(mContentDisposition);
+
+  // Each part of a multipart/replace response can be used
+  // for the top level document.  We must inform upper layers
+  // about this by setting the LOAD_REPLACE flag so that certain
+  // state assertions are evaluated as positive.
+  nsLoadFlags loadFlags = 0;
+  mPartChannel->GetLoadFlags(&loadFlags);
+  loadFlags |= nsIChannel::LOAD_REPLACE;
+  mPartChannel->SetLoadFlags(loadFlags);
+
+  nsCOMPtr<nsILoadGroup> loadGroup;
+  (void)mPartChannel->GetLoadGroup(getter_AddRefs(loadGroup));
+
+  // Add the new channel to the load group (if any)
+  if (loadGroup) {
+    rv = loadGroup->AddRequest(mPartChannel, nullptr);
+    if (NS_FAILED(rv)) return rv;
+  }
+
+  // This prevents artificial call to OnStart/StopRequest when the root
+  // channel fails.  Since now it's ensured to keep with the nsIStreamListener
+  // contract every time.
+  mRequestListenerNotified = true;
+
+  // Let's start off the load. NOTE: we don't forward on the channel passed
+  // into our OnDataAvailable() as it's the root channel for the raw stream.
+  return mPartChannel->SendOnStartRequest(mContext);
+}
+
+nsresult nsMultiMixedConv::SendStop(nsresult aStatus) {
+  // Make sure we send out all accumulcated data prior call to OnStopRequest.
+  // If there is no data, this is a no-op.
+  nsresult rv = SendData();
+  if (NS_SUCCEEDED(aStatus)) {
+    aStatus = rv;
+  }
+  if (mPartChannel) {
+    rv = mPartChannel->SendOnStopRequest(mContext, aStatus);
+    // don't check for failure here, we need to remove the channel from
+    // the loadgroup.
+
+    // Remove the channel from its load group (if any)
+    nsCOMPtr<nsILoadGroup> loadGroup;
+    (void)mPartChannel->GetLoadGroup(getter_AddRefs(loadGroup));
+    if (loadGroup) {
+      (void)loadGroup->RemoveRequest(mPartChannel, mContext, aStatus);
+    }
+  }
+
+  mPartChannel = nullptr;
+  return rv;
+}
+
+void nsMultiMixedConv::AccumulateData(Token const& aToken) {
+  if (!mRawData) {
+    // This is the first read of raw data during this FeedInput loop
+    // of the incremental tokenizer.  All 'raw' tokens are coming from
+    // the same linear buffer, hence begining of this loop raw data
+    // is begining of the first raw token.  Length of this loop raw
+    // data is just sum of all 'raw' tokens we collect during this loop.
+    //
+    // It's ensured we flush (send to to the listener via OnDataAvailable)
+    // and nullify the collected raw data right after FeedInput call.
+    // Hence, the reference can't outlive the actual buffer.
+    mRawData = aToken.Fragment().BeginReading();
+    mRawDataLength = 0;
+  }
+
+  mRawDataLength += aToken.Fragment().Length();
+}
+
+nsresult nsMultiMixedConv::SendData() {
+  nsresult rv;
+
+  if (!mRawData) {
+    return NS_OK;
+  }
+
+  nsACString::const_char_iterator rawData = mRawData;
+  mRawData = nullptr;
+
+  if (!mPartChannel) {
+    return NS_ERROR_FAILURE;  // something went wrong w/ processing
+  }
+
+  if (mContentLength != UINT64_MAX) {
+    // make sure that we don't send more than the mContentLength
+    // XXX why? perhaps the Content-Length header was actually wrong!!
+    if ((uint64_t(mRawDataLength) + mTotalSent) > mContentLength) {
+      mRawDataLength = static_cast<uint32_t>(mContentLength - mTotalSent);
+    }
+
+    if (mRawDataLength == 0) return NS_OK;
+  }
+
+  uint64_t offset = mTotalSent;
+  mTotalSent += mRawDataLength;
+
+  nsCOMPtr<nsIStringInputStream> ss(
+      do_CreateInstance("@mozilla.org/io/string-input-stream;1", &rv));
+  if (NS_FAILED(rv)) return rv;
+
+  rv = ss->ShareData(rawData, mRawDataLength);
+  mRawData = nullptr;
+  if (NS_FAILED(rv)) return rv;
+
+  return mPartChannel->SendOnDataAvailable(mContext, ss, offset,
+                                           mRawDataLength);
+}
+
+void nsMultiMixedConv::HeadersToDefault() {
+  mContentLength = UINT64_MAX;
+  mContentType.Truncate();
+  mContentDisposition.Truncate();
+  mContentSecurityPolicy.Truncate();
+  mIsByteRangeRequest = false;
+}
+
+nsresult nsMultiMixedConv::ProcessHeader() {
+  mozilla::Tokenizer p(mResponseHeaderValue);
+
+  switch (mResponseHeader) {
+    case HEADER_CONTENT_TYPE:
+      mContentType = mResponseHeaderValue;
+      mContentType.CompressWhitespace();
+      break;
+    case HEADER_CONTENT_LENGTH:
+      p.SkipWhites();
+      if (!p.ReadInteger(&mContentLength)) {
+        return NS_ERROR_CORRUPTED_CONTENT;
+      }
+      break;
+    case HEADER_CONTENT_DISPOSITION:
+      mContentDisposition = mResponseHeaderValue;
+      mContentDisposition.CompressWhitespace();
+      break;
+    case HEADER_SET_COOKIE: {
+      nsCOMPtr<nsIHttpChannelInternal> httpInternal =
+          do_QueryInterface(mChannel);
+      mResponseHeaderValue.CompressWhitespace();
+      if (!StaticPrefs::network_cookie_prevent_set_cookie_from_multipart() &&
+          httpInternal) {
+        DebugOnly<nsresult> rv = httpInternal->SetCookie(mResponseHeaderValue);
+        MOZ_ASSERT(NS_SUCCEEDED(rv));
+      }
+      break;
+    }
+    case HEADER_RANGE:
+    case HEADER_CONTENT_RANGE: {
+      if (!p.CheckWord("bytes") || !p.CheckWhite()) {
+        return NS_ERROR_CORRUPTED_CONTENT;
+      }
+      p.SkipWhites();
+      if (p.CheckChar('*')) {
+        mByteRangeStart = mByteRangeEnd = 0;
+      } else if (!p.ReadInteger(&mByteRangeStart) || !p.CheckChar('-') ||
+                 !p.ReadInteger(&mByteRangeEnd)) {
+        return NS_ERROR_CORRUPTED_CONTENT;
+      }
+      mIsByteRangeRequest = true;
+      if (mContentLength == UINT64_MAX) {
+        mContentLength = uint64_t(mByteRangeEnd - mByteRangeStart + 1);
+      }
+      break;
+    }
+    case HEADER_CONTENT_SECURITY_POLICY: {
+      mContentSecurityPolicy = mResponseHeaderValue;
+      mContentSecurityPolicy.CompressWhitespace();
+      nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(mChannel);
+      if (httpChannel) {
+        nsCString resultCSP = mRootContentSecurityPolicy;
+        if (!mContentSecurityPolicy.IsEmpty()) {
+          // We are updating the root channel CSP header respectively for
+          // each part as: CSP-root + CSP-partN, where N is the part number.
+          // Here we append current part's CSP to root CSP and reset CSP
+          // header for each part.
+          if (!resultCSP.IsEmpty()) {
+            resultCSP.Append(";");
+          }
+          resultCSP.Append(mContentSecurityPolicy);
+        }
+        nsresult rv = httpChannel->SetResponseHeader(
+            "Content-Security-Policy"_ns, resultCSP, false);
+        if (NS_FAILED(rv)) {
+          return NS_ERROR_CORRUPTED_CONTENT;
+        }
+      }
+      break;
+    }
+    case HEADER_UNKNOWN:
+      // We ignore anything else...
+      break;
+  }
+
+  return NS_OK;
+}
+
+nsresult NS_NewMultiMixedConv(nsMultiMixedConv** aMultiMixedConv) {
+  MOZ_ASSERT(aMultiMixedConv != nullptr, "null ptr");
+
+  RefPtr<nsMultiMixedConv> conv = new nsMultiMixedConv();
+  conv.forget(aMultiMixedConv);
+  return NS_OK;
+}
diff --git a/netwerk/streamconv/converters/nsMultiMixedConv.h b/netwerk/streamconv/converters/nsMultiMixedConv.h
new file mode 100644
index 0000000000..4f773a69eb
--- /dev/null
+++ b/netwerk/streamconv/converters/nsMultiMixedConv.h
@@ -0,0 +1,259 @@
+/* -*- Mode: C++; tab-width: 4; 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 __nsmultimixedconv__h__
+#define __nsmultimixedconv__h__
+
+#include "nsIStreamConverter.h"
+#include "nsIChannel.h"
+#include "nsString.h"
+#include "nsCOMPtr.h"
+#include "nsIByteRangeRequest.h"
+#include "nsIMultiPartChannel.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/IncrementalTokenizer.h"
+#include "nsHttpResponseHead.h"
+#include "mozilla/UniquePtr.h"
+
+#define NS_MULTIMIXEDCONVERTER_CID                 \
+  { /* 7584CE90-5B25-11d3-A175-0050041CAF44 */     \
+    0x7584ce90, 0x5b25, 0x11d3, {                  \
+      0xa1, 0x75, 0x0, 0x50, 0x4, 0x1c, 0xaf, 0x44 \
+    }                                              \
+  }
+
+//
+// nsPartChannel is a "dummy" channel which represents an individual part of
+// a multipart/mixed stream...
+//
+// Instances on this channel are passed out to the consumer through the
+// nsIStreamListener interface.
+//
+class nsPartChannel final : public nsIChannel,
+                            public nsIByteRangeRequest,
+                            public nsIMultiPartChannel {
+ public:
+  nsPartChannel(nsIChannel* aMultipartChannel, uint32_t aPartID,
+                bool aIsFirstPart, nsIStreamListener* aListener);
+
+  void InitializeByteRange(int64_t aStart, int64_t aEnd);
+  void SetIsLastPart() { mIsLastPart = true; }
+  nsresult SendOnStartRequest(nsISupports* aContext);
+  nsresult SendOnDataAvailable(nsISupports* aContext, nsIInputStream* aStream,
+                               uint64_t aOffset, uint32_t aLen);
+  nsresult SendOnStopRequest(nsISupports* aContext, nsresult aStatus);
+  /* SetContentDisposition expects the full value of the Content-Disposition
+   * header */
+  void SetContentDisposition(const nsACString& aContentDispositionHeader);
+  // TODO(ER): This appears to be dead code
+  void SetResponseHead(mozilla::net::nsHttpResponseHead* head) {
+    mResponseHead.reset(head);
+  }
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIREQUEST
+  NS_DECL_NSICHANNEL
+  NS_DECL_NSIBYTERANGEREQUEST
+  NS_DECL_NSIMULTIPARTCHANNEL
+
+ protected:
+  ~nsPartChannel() = default;
+
+ protected:
+  nsCOMPtr<nsIChannel> mMultipartChannel;
+  nsCOMPtr<nsIStreamListener> mListener;
+  mozilla::UniquePtr<mozilla::net::nsHttpResponseHead> mResponseHead;
+
+  nsresult mStatus{NS_OK};
+  nsLoadFlags mLoadFlags{0};
+
+  nsCOMPtr<nsILoadGroup> mLoadGroup;
+
+  nsCString mContentType;
+  nsCString mContentCharset;
+  uint32_t mContentDisposition{0};
+  nsString mContentDispositionFilename;
+  nsCString mContentDispositionHeader;
+  uint64_t mContentLength{UINT64_MAX};
+
+  bool mIsByteRangeRequest{false};
+  int64_t mByteRangeStart{0};
+  int64_t mByteRangeEnd{0};
+
+  uint32_t mPartID;  // unique ID that can be used to identify
+                     // this part of the multipart document
+  bool mIsFirstPart;
+  bool mIsLastPart{false};
+};
+
+// The nsMultiMixedConv stream converter converts a stream of type
+// "multipart/x-mixed-replace" to it's subparts. There was some debate as to
+// whether or not the functionality desired when HTTP confronted this type
+// required a stream converter. After all, this type really prompts various
+// viewer related actions rather than stream conversion. There simply needs to
+// be a piece in place that can strip out the multiple parts of a stream of this
+// type, and "display" them accordingly.
+//
+// With that said, this "stream converter" spends more time packaging up the sub
+// parts of the main stream and sending them off the destination stream
+// listener, than doing any real stream parsing/converting.
+//
+// WARNING: This converter requires that it's destination stream listener be
+//   able to handle multiple OnStartRequest(), OnDataAvailable(), and
+//   OnStopRequest() call combinations.  Each series represents the beginning,
+//   data production, and ending phase of each sub- part of the original
+//   stream.
+//
+// NOTE: this MIME-type is used by HTTP, *not* SMTP, or IMAP.
+//
+// NOTE: For reference, a general description of how this MIME type should be
+//   handled via HTTP, see
+//   http://home.netscape.com/assist/net_sites/pushpull.html . Note that real
+//   world server content deviates considerably from this overview.
+//
+// Implementation assumptions:
+//  Assumed structue:
+//  --BoundaryToken[\r]\n
+//  content-type: foo/bar[\r]\n
+//  ... (other headers if any)
+//  [\r]\n (second line feed to delimit end of headers)
+//  data
+//  --BoundaryToken-- (end delimited by final "--")
+//
+// linebreaks can be either CRLF or LFLF. linebreaks preceding
+// boundary tokens are NOT considered part of the data. BoundaryToken
+// is any opaque string.
+//
+//
+
+class nsMultiMixedConv : public nsIStreamConverter {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISTREAMCONVERTER
+  NS_DECL_NSISTREAMLISTENER
+  NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER
+  NS_DECL_NSIREQUESTOBSERVER
+
+  explicit nsMultiMixedConv();
+
+ protected:
+  using Token = mozilla::IncrementalTokenizer::Token;
+
+  virtual ~nsMultiMixedConv() = default;
+
+  nsresult SendStart();
+  void AccumulateData(Token const& aToken);
+  nsresult SendData();
+  nsresult SendStop(nsresult aStatus);
+
+  // member data
+  nsCOMPtr<nsIStreamListener> mFinalListener;  // this guy gets the converted
+                                               // data via his OnDataAvailable()
+
+  nsCOMPtr<nsIChannel>
+      mChannel;  // The channel as we get in in OnStartRequest call
+  RefPtr<nsPartChannel> mPartChannel;  // the channel for the given part we're
+                                       // processing. one channel per part.
+  nsCOMPtr<nsISupports> mContext;
+  nsCString mContentType;
+  nsCString mContentDisposition;
+  nsCString mContentSecurityPolicy;
+  nsCString mRootContentSecurityPolicy;
+  uint64_t mContentLength{UINT64_MAX};
+  uint64_t mTotalSent{0};
+
+  // The following members are for tracking the byte ranges in
+  // multipart/mixed content which specified the 'Content-Range:'
+  // header...
+  int64_t mByteRangeStart{0};
+  int64_t mByteRangeEnd{0};
+  bool mIsByteRangeRequest{false};
+  // This flag is set first time we create a part channel.
+  // We use it to prevent duplicated OnStopRequest call on the listener
+  // when we fail from some reason to ever create a part channel that
+  // ensures correct notifications.
+  bool mRequestListenerNotified{false};
+
+  uint32_t mCurrentPartID{0};
+
+  // Flag preventing reenter of OnDataAvailable in case the target listener
+  // ends up spinning the event loop.
+  bool mInOnDataAvailable{false};
+
+  // Current state of the incremental parser
+  enum EParserState {
+    PREAMBLE,
+    BOUNDARY_CRLF,
+    HEADER_NAME,
+    HEADER_SEP,
+    HEADER_VALUE,
+    BODY_INIT,
+    BODY,
+    TRAIL_DASH1,
+    TRAIL_DASH2,
+    EPILOGUE,
+
+    INIT = PREAMBLE
+  } mParserState{INIT};
+
+  // Response part header value, valid when we find a header name
+  // we recognize.
+  enum EHeader : uint32_t {
+    HEADER_FIRST,
+    HEADER_CONTENT_TYPE = HEADER_FIRST,
+    HEADER_CONTENT_LENGTH,
+    HEADER_CONTENT_DISPOSITION,
+    HEADER_SET_COOKIE,
+    HEADER_CONTENT_RANGE,
+    HEADER_RANGE,
+    HEADER_CONTENT_SECURITY_POLICY,
+    HEADER_UNKNOWN
+  } mResponseHeader{HEADER_UNKNOWN};
+  // Cumulated value of a response header.
+  nsCString mResponseHeaderValue;
+
+  nsCString mBoundary;
+  mozilla::IncrementalTokenizer mTokenizer;
+
+  // When in the "body parsing" mode, see below, we cumulate raw data
+  // incrementally to mainly avoid any unnecessary granularity.
+  // mRawData points to the first byte in the tokenizer buffer where part
+  // body data begins or continues.  mRawDataLength is a cumulated length
+  // of that data during a single tokenizer input feed.  This is always
+  // flushed right after we fed the tokenizer.
+  nsACString::const_char_iterator mRawData{nullptr};
+  nsACString::size_type mRawDataLength{0};
+
+  // At the start we don't know if the server will be sending boundary with
+  // or without the leading dashes.
+  Token mBoundaryToken;
+  Token mBoundaryTokenWithDashes;
+  // We need these custom tokens to allow finding CRLF when in the binary mode.
+  // CRLF before boundary is considered part of the boundary and not part of
+  // the data.
+  Token mLFToken;
+  Token mCRLFToken;
+  // Custom tokens for each of the response headers we recognize.
+  Token mHeaderTokens[HEADER_UNKNOWN];
+
+  // Resets values driven by part headers, like content type, to their defaults,
+  // called at the start of every part processing.
+  void HeadersToDefault();
+  // Processes captured value of mResponseHeader header.
+  nsresult ProcessHeader();
+  // Switches the parser and tokenizer state to "binary mode" which only
+  // searches for the 'CRLF boundary' delimiter.
+  void SwitchToBodyParsing();
+  // Switches to the default mode, we are in this mode when parsing headers and
+  // control data around the boundary delimiters.
+  void SwitchToControlParsing();
+  // Turns on or off recognition of the headers we recognize in part heads.
+  void SetHeaderTokensEnabled(bool aEnable);
+
+  // The main parser callback called by the IncrementalTokenizer
+  // instance from OnDataAvailable or OnStopRequest.
+  nsresult ConsumeToken(Token const& token);
+};
+
+#endif /* __nsmultimixedconv__h__ */
diff --git a/netwerk/streamconv/converters/nsUnknownDecoder.cpp b/netwerk/streamconv/converters/nsUnknownDecoder.cpp
new file mode 100644
index 0000000000..b572b1c276
--- /dev/null
+++ b/netwerk/streamconv/converters/nsUnknownDecoder.cpp
@@ -0,0 +1,867 @@
+/* -*- 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 "nsUnknownDecoder.h"
+#include "nsIPipe.h"
+#include "nsIInputStream.h"
+#include "nsIOutputStream.h"
+#include "nsMimeTypes.h"
+
+#include "nsCRT.h"
+
+#include "nsIMIMEService.h"
+
+#include "nsIViewSourceChannel.h"
+#include "nsIHttpChannel.h"
+#include "nsIForcePendingChannel.h"
+#include "nsIEncodedChannel.h"
+#include "nsIURI.h"
+#include "nsStringStream.h"
+#include "nsNetCID.h"
+#include "nsNetUtil.h"
+#include "nsQueryObject.h"
+#include "nsComponentManagerUtils.h"
+#include "nsServiceManagerUtils.h"
+
+#include <algorithm>
+
+#define MAX_BUFFER_SIZE 512u
+
+using namespace mozilla;
+
+NS_IMPL_ISUPPORTS(nsUnknownDecoder::ConvertedStreamListener, nsIStreamListener,
+                  nsIRequestObserver)
+
+nsUnknownDecoder::ConvertedStreamListener::ConvertedStreamListener(
+    nsUnknownDecoder* aDecoder) {
+  mDecoder = aDecoder;
+}
+
+nsresult nsUnknownDecoder::ConvertedStreamListener::AppendDataToString(
+    nsIInputStream* inputStream, void* closure, const char* rawSegment,
+    uint32_t toOffset, uint32_t count, uint32_t* writeCount) {
+  nsCString* decodedData = static_cast<nsCString*>(closure);
+  decodedData->Append(rawSegment, count);
+  *writeCount = count;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsUnknownDecoder::ConvertedStreamListener::OnStartRequest(nsIRequest* request) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsUnknownDecoder::ConvertedStreamListener::OnDataAvailable(
+    nsIRequest* request, nsIInputStream* stream, uint64_t offset,
+    uint32_t count) {
+  uint32_t read;
+  nsAutoCString decodedData;
+  {
+    MutexAutoLock lock(mDecoder->mMutex);
+    decodedData = mDecoder->mDecodedData;
+  }
+  nsresult rv =
+      stream->ReadSegments(AppendDataToString, &decodedData, count, &read);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  MutexAutoLock lock(mDecoder->mMutex);
+  mDecoder->mDecodedData = decodedData;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsUnknownDecoder::ConvertedStreamListener::OnStopRequest(nsIRequest* request,
+                                                         nsresult status) {
+  return NS_OK;
+}
+
+nsUnknownDecoder::nsUnknownDecoder(nsIStreamListener* aListener)
+    : mNextListener(aListener),
+      mBuffer(nullptr),
+      mBufferLen(0),
+      mMutex("nsUnknownDecoder"),
+      mDecodedData("") {}
+
+nsUnknownDecoder::~nsUnknownDecoder() {
+  if (mBuffer) {
+    delete[] mBuffer;
+    mBuffer = nullptr;
+  }
+}
+
+// ----
+//
+// nsISupports implementation...
+//
+// ----
+
+NS_IMPL_ADDREF(nsUnknownDecoder)
+NS_IMPL_RELEASE(nsUnknownDecoder)
+
+NS_INTERFACE_MAP_BEGIN(nsUnknownDecoder)
+  NS_INTERFACE_MAP_ENTRY(nsIStreamConverter)
+  NS_INTERFACE_MAP_ENTRY(nsIStreamListener)
+  NS_INTERFACE_MAP_ENTRY(nsIRequestObserver)
+  NS_INTERFACE_MAP_ENTRY(nsIContentSniffer)
+  NS_INTERFACE_MAP_ENTRY(nsIThreadRetargetableStreamListener)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports,
+                                   nsIThreadRetargetableStreamListener)
+NS_INTERFACE_MAP_END
+
+// ----
+//
+// nsIStreamConverter methods...
+//
+// ----
+
+NS_IMETHODIMP
+nsUnknownDecoder::Convert(nsIInputStream* aFromStream, const char* aFromType,
+                          const char* aToType, nsISupports* aCtxt,
+                          nsIInputStream** aResultStream) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsUnknownDecoder::AsyncConvertData(const char* aFromType, const char* aToType,
+                                   nsIStreamListener* aListener,
+                                   nsISupports* aCtxt) {
+  NS_ASSERTION(aListener && aFromType && aToType,
+               "null pointer passed into multi mixed converter");
+  // hook up our final listener. this guy gets the various On*() calls we want
+  // to throw at him.
+  //
+
+  MutexAutoLock lock(mMutex);
+  mNextListener = aListener;
+  return (aListener) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsUnknownDecoder::GetConvertedType(const nsACString& aFromType,
+                                   nsIChannel* aChannel, nsACString& aToType) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+// ----
+//
+// nsIStreamListener methods...
+//
+// ----
+
+NS_IMETHODIMP
+nsUnknownDecoder::OnDataAvailable(nsIRequest* request, nsIInputStream* aStream,
+                                  uint64_t aSourceOffset, uint32_t aCount) {
+  nsresult rv = NS_OK;
+
+  bool contentTypeEmpty;
+  {
+    MutexAutoLock lock(mMutex);
+    if (!mNextListener) return NS_ERROR_FAILURE;
+
+    contentTypeEmpty = mContentType.IsEmpty();
+  }
+
+  if (contentTypeEmpty) {
+    uint32_t count, len;
+
+    // If the buffer has not been allocated by now, just fail...
+    if (!mBuffer) return NS_ERROR_OUT_OF_MEMORY;
+
+    //
+    // Determine how much of the stream should be read to fill up the
+    // sniffer buffer...
+    //
+    if (mBufferLen + aCount >= MAX_BUFFER_SIZE) {
+      count = MAX_BUFFER_SIZE - mBufferLen;
+    } else {
+      count = aCount;
+    }
+
+    // Read the data into the buffer...
+    rv = aStream->Read((mBuffer + mBufferLen), count, &len);
+    if (NS_FAILED(rv)) return rv;
+
+    mBufferLen += len;
+    aCount -= len;
+
+    if (aCount) {
+      //
+      // Adjust the source offset...  The call to FireListenerNotifications(...)
+      // will make the first OnDataAvailable(...) call with an offset of 0.
+      // So, this offset needs to be adjusted to reflect that...
+      //
+      aSourceOffset += mBufferLen;
+
+      DetermineContentType(request);
+
+      rv = FireListenerNotifications(request, nullptr);
+    }
+  }
+
+  // Must not fire ODA again if it failed once
+  if (aCount && NS_SUCCEEDED(rv)) {
+#ifdef DEBUG
+    {
+      MutexAutoLock lock(mMutex);
+      NS_ASSERTION(!mContentType.IsEmpty(),
+                   "Content type should be known by now.");
+    }
+#endif
+
+    nsCOMPtr<nsIStreamListener> listener;
+    {
+      MutexAutoLock lock(mMutex);
+      listener = mNextListener;
+    }
+    rv = listener->OnDataAvailable(request, aStream, aSourceOffset, aCount);
+  }
+
+  return rv;
+}
+
+// ----
+//
+// nsIRequestObserver methods...
+//
+// ----
+
+NS_IMETHODIMP
+nsUnknownDecoder::OnStartRequest(nsIRequest* request) {
+  nsresult rv = NS_OK;
+
+  {
+    MutexAutoLock lock(mMutex);
+    if (!mNextListener) return NS_ERROR_FAILURE;
+  }
+
+  // Allocate the sniffer buffer...
+  if (NS_SUCCEEDED(rv) && !mBuffer) {
+    mBuffer = new char[MAX_BUFFER_SIZE];
+
+    if (!mBuffer) {
+      rv = NS_ERROR_OUT_OF_MEMORY;
+    }
+  }
+
+  // Do not pass the OnStartRequest on to the next listener (yet)...
+  return rv;
+}
+
+NS_IMETHODIMP
+nsUnknownDecoder::OnStopRequest(nsIRequest* request, nsresult aStatus) {
+  nsresult rv = NS_OK;
+
+  bool contentTypeEmpty;
+  {
+    MutexAutoLock lock(mMutex);
+    if (!mNextListener) return NS_ERROR_FAILURE;
+
+    contentTypeEmpty = mContentType.IsEmpty();
+  }
+
+  //
+  // The total amount of data is less than the size of the sniffer buffer.
+  // Analyze the buffer now...
+  //
+  if (contentTypeEmpty) {
+    DetermineContentType(request);
+
+    // Make sure channel listeners see channel as pending while we call
+    // OnStartRequest/OnDataAvailable, even though the underlying channel
+    // has already hit OnStopRequest.
+    nsCOMPtr<nsIForcePendingChannel> forcePendingChannel =
+        do_QueryInterface(request);
+    if (forcePendingChannel) {
+      forcePendingChannel->ForcePending(true);
+    }
+
+    rv = FireListenerNotifications(request, nullptr);
+
+    if (NS_FAILED(rv)) {
+      aStatus = rv;
+    }
+
+    // now we need to set pending state to false before calling OnStopRequest
+    if (forcePendingChannel) {
+      forcePendingChannel->ForcePending(false);
+    }
+  }
+
+  nsCOMPtr<nsIStreamListener> listener;
+  {
+    MutexAutoLock lock(mMutex);
+    listener = mNextListener;
+    mNextListener = nullptr;
+  }
+  rv = listener->OnStopRequest(request, aStatus);
+
+  return rv;
+}
+
+// ----
+//
+// nsIContentSniffer methods...
+//
+// ----
+NS_IMETHODIMP
+nsUnknownDecoder::GetMIMETypeFromContent(nsIRequest* aRequest,
+                                         const uint8_t* aData, uint32_t aLength,
+                                         nsACString& type) {
+  // This is only used by sniffer, therefore we do not need to lock anything
+  // here.
+  nsCOMPtr<nsIChannel> channel(do_QueryInterface(aRequest));
+  if (channel) {
+    nsCOMPtr<nsILoadInfo> loadInfo = channel->LoadInfo();
+    if (loadInfo->GetSkipContentSniffing()) {
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+  }
+
+  mBuffer = const_cast<char*>(reinterpret_cast<const char*>(aData));
+  mBufferLen = aLength;
+  DetermineContentType(aRequest);
+  mBuffer = nullptr;
+  mBufferLen = 0;
+  type.Assign(mContentType);
+  mContentType.Truncate();
+  return type.IsEmpty() ? NS_ERROR_NOT_AVAILABLE : NS_OK;
+}
+
+// Actual sniffing code
+
+/**
+ * This is the array of sniffer entries that depend on "magic numbers"
+ * in the file.  Each entry has either a type associated with it (set
+ * these with the SNIFFER_ENTRY macro) or a function to be executed
+ * (set these with the SNIFFER_ENTRY_WITH_FUNC macro).  The function
+ * should take a single nsIRequest* and returns bool -- true if
+ * it sets mContentType, false otherwise
+ */
+nsUnknownDecoder::nsSnifferEntry nsUnknownDecoder::sSnifferEntries[] = {
+    SNIFFER_ENTRY("%PDF-", APPLICATION_PDF),
+
+    SNIFFER_ENTRY("%!PS-Adobe-", APPLICATION_POSTSCRIPT),
+
+    // Files that start with mailbox delimiters let's provisionally call
+    // text/plain
+    SNIFFER_ENTRY("From", TEXT_PLAIN), SNIFFER_ENTRY(">From", TEXT_PLAIN),
+
+    // If the buffer begins with "#!" or "%!" then it is a script of
+    // some sort...  "Scripts" can include arbitrary data to be passed
+    // to an interpreter, so we need to decide whether we can call this
+    // text or whether it's data.
+    SNIFFER_ENTRY_WITH_FUNC("#!", &nsUnknownDecoder::LastDitchSniff),
+
+    // XXXbz should (and can) we also include the various ways that <?xml can
+    // appear as UTF-16 and such?  See http://www.w3.org/TR/REC-xml#sec-guessing
+    SNIFFER_ENTRY_WITH_FUNC("<?xml", &nsUnknownDecoder::SniffForXML)};
+
+uint32_t nsUnknownDecoder::sSnifferEntryNum =
+    sizeof(nsUnknownDecoder::sSnifferEntries) /
+    sizeof(nsUnknownDecoder::nsSnifferEntry);
+
+void nsUnknownDecoder::DetermineContentType(nsIRequest* aRequest) {
+  {
+    MutexAutoLock lock(mMutex);
+    NS_ASSERTION(mContentType.IsEmpty(), "Content type is already known.");
+    if (!mContentType.IsEmpty()) return;
+  }
+
+  nsCOMPtr<nsIChannel> channel(do_QueryInterface(aRequest));
+  if (channel) {
+    nsCOMPtr<nsILoadInfo> loadInfo = channel->LoadInfo();
+    if (loadInfo->GetSkipContentSniffing()) {
+      /*
+       * If we did not get a useful Content-Type from the server
+       * but also have sniffing disabled, just determine whether
+       * to use text/plain or octetstream and log an error to the Console
+       */
+      LastDitchSniff(aRequest);
+
+      nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(aRequest));
+      if (httpChannel) {
+        nsAutoCString type;
+        httpChannel->GetContentType(type);
+        nsCOMPtr<nsIURI> requestUri;
+        httpChannel->GetURI(getter_AddRefs(requestUri));
+        nsAutoCString spec;
+        requestUri->GetSpec(spec);
+        if (spec.Length() > 50) {
+          spec.Truncate(50);
+          spec.AppendLiteral("...");
+        }
+        httpChannel->LogMimeTypeMismatch(
+            "XTCOWithMIMEValueMissing"_ns, false, NS_ConvertUTF8toUTF16(spec),
+            // Type is not used in the Error Message but required
+            NS_ConvertUTF8toUTF16(type));
+      }
+      return;
+    }
+  }
+
+  const char* testData = mBuffer;
+  uint32_t testDataLen = mBufferLen;
+  // Check if data are compressed.
+  nsAutoCString decodedData;
+
+  if (channel) {
+    // ConvertEncodedData is always called only on a single thread for each
+    // instance of an object.
+    nsresult rv = ConvertEncodedData(aRequest, mBuffer, mBufferLen);
+    if (NS_SUCCEEDED(rv)) {
+      MutexAutoLock lock(mMutex);
+      decodedData = mDecodedData;
+    }
+    if (!decodedData.IsEmpty()) {
+      testData = decodedData.get();
+      testDataLen = std::min<uint32_t>(decodedData.Length(), MAX_BUFFER_SIZE);
+    }
+  }
+
+  // First, run through all the types we can detect reliably based on
+  // magic numbers
+  uint32_t i;
+  for (i = 0; i < sSnifferEntryNum; ++i) {
+    if (testDataLen >= sSnifferEntries[i].mByteLen &&  // enough data
+        memcmp(testData, sSnifferEntries[i].mBytes,
+               sSnifferEntries[i].mByteLen) == 0) {  // and type matches
+      NS_ASSERTION(
+          sSnifferEntries[i].mMimeType ||
+              sSnifferEntries[i].mContentTypeSniffer,
+          "Must have either a type string or a function to set the type");
+      NS_ASSERTION(!sSnifferEntries[i].mMimeType ||
+                       !sSnifferEntries[i].mContentTypeSniffer,
+                   "Both a type string and a type sniffing function set;"
+                   " using type string");
+      if (sSnifferEntries[i].mMimeType) {
+        MutexAutoLock lock(mMutex);
+        mContentType = sSnifferEntries[i].mMimeType;
+        NS_ASSERTION(!mContentType.IsEmpty(),
+                     "Content type should be known by now.");
+        return;
+      }
+      if ((this->*(sSnifferEntries[i].mContentTypeSniffer))(aRequest)) {
+#ifdef DEBUG
+        MutexAutoLock lock(mMutex);
+        NS_ASSERTION(!mContentType.IsEmpty(),
+                     "Content type should be known by now.");
+#endif
+        return;
+      }
+    }
+  }
+
+  nsAutoCString sniffedType;
+  NS_SniffContent(NS_DATA_SNIFFER_CATEGORY, aRequest, (const uint8_t*)testData,
+                  testDataLen, sniffedType);
+  {
+    MutexAutoLock lock(mMutex);
+    mContentType = sniffedType;
+    if (!mContentType.IsEmpty()) {
+      return;
+    }
+  }
+
+  if (SniffForHTML(aRequest)) {
+#ifdef DEBUG
+    MutexAutoLock lock(mMutex);
+    NS_ASSERTION(!mContentType.IsEmpty(),
+                 "Content type should be known by now.");
+#endif
+    return;
+  }
+
+  // We don't know what this is yet.  Before we just give up, try
+  // the URI from the request.
+  if (SniffURI(aRequest)) {
+#ifdef DEBUG
+    MutexAutoLock lock(mMutex);
+    NS_ASSERTION(!mContentType.IsEmpty(),
+                 "Content type should be known by now.");
+#endif
+    return;
+  }
+
+  LastDitchSniff(aRequest);
+#ifdef DEBUG
+  MutexAutoLock lock(mMutex);
+  NS_ASSERTION(!mContentType.IsEmpty(), "Content type should be known by now.");
+#endif
+}
+
+bool nsUnknownDecoder::SniffForHTML(nsIRequest* aRequest) {
+  MutexAutoLock lock(mMutex);
+
+  // Now look for HTML.
+  const char* str;
+  const char* end;
+  if (mDecodedData.IsEmpty()) {
+    str = mBuffer;
+    end = mBuffer + mBufferLen;
+  } else {
+    str = mDecodedData.get();
+    end = mDecodedData.get() +
+          std::min<uint32_t>(mDecodedData.Length(), MAX_BUFFER_SIZE);
+  }
+
+  // skip leading whitespace
+  while (str != end && nsCRT::IsAsciiSpace(*str)) {
+    ++str;
+  }
+
+  // did we find something like a start tag?
+  if (str == end || *str != '<' || ++str == end) {
+    return false;
+  }
+
+  // If we seem to be SGML or XML and we got down here, just pretend we're HTML
+  if (*str == '!' || *str == '?') {
+    mContentType = TEXT_HTML;
+    return true;
+  }
+
+  uint32_t bufSize = end - str;
+  // We use sizeof(_tagstr) below because that's the length of _tagstr
+  // with the one char " " or ">" appended.
+#define MATCHES_TAG(_tagstr)                                      \
+  (bufSize >= sizeof(_tagstr) &&                                  \
+   (nsCRT::strncasecmp(str, _tagstr " ", sizeof(_tagstr)) == 0 || \
+    nsCRT::strncasecmp(str, _tagstr ">", sizeof(_tagstr)) == 0))
+
+  if (MATCHES_TAG("html") || MATCHES_TAG("frameset") || MATCHES_TAG("body") ||
+      MATCHES_TAG("head") || MATCHES_TAG("script") || MATCHES_TAG("iframe") ||
+      MATCHES_TAG("a") || MATCHES_TAG("img") || MATCHES_TAG("table") ||
+      MATCHES_TAG("title") || MATCHES_TAG("link") || MATCHES_TAG("base") ||
+      MATCHES_TAG("style") || MATCHES_TAG("div") || MATCHES_TAG("p") ||
+      MATCHES_TAG("font") || MATCHES_TAG("applet") || MATCHES_TAG("meta") ||
+      MATCHES_TAG("center") || MATCHES_TAG("form") || MATCHES_TAG("isindex") ||
+      MATCHES_TAG("h1") || MATCHES_TAG("h2") || MATCHES_TAG("h3") ||
+      MATCHES_TAG("h4") || MATCHES_TAG("h5") || MATCHES_TAG("h6") ||
+      MATCHES_TAG("b") || MATCHES_TAG("pre")) {
+    mContentType = TEXT_HTML;
+    return true;
+  }
+
+#undef MATCHES_TAG
+
+  return false;
+}
+
+bool nsUnknownDecoder::SniffForXML(nsIRequest* aRequest) {
+  // First see whether we can glean anything from the uri...
+  if (!SniffURI(aRequest)) {
+    // Oh well; just generic XML will have to do
+    MutexAutoLock lock(mMutex);
+    mContentType = TEXT_XML;
+  }
+
+  return true;
+}
+
+bool nsUnknownDecoder::SniffURI(nsIRequest* aRequest) {
+  nsCOMPtr<nsIChannel> channel(do_QueryInterface(aRequest));
+  nsCOMPtr<nsILoadInfo> loadInfo = channel->LoadInfo();
+  if (loadInfo->GetSkipContentSniffing()) {
+    return false;
+  }
+  nsCOMPtr<nsIMIMEService> mimeService(do_GetService("@mozilla.org/mime;1"));
+  if (mimeService) {
+    nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest);
+    if (channel) {
+      nsCOMPtr<nsIURI> uri;
+      nsresult result = channel->GetURI(getter_AddRefs(uri));
+      if (NS_SUCCEEDED(result) && uri) {
+        nsAutoCString type;
+        result = mimeService->GetTypeFromURI(uri, type);
+        if (NS_SUCCEEDED(result)) {
+          MutexAutoLock lock(mMutex);
+          mContentType = type;
+          return true;
+        }
+      }
+    }
+  }
+
+  return false;
+}
+
+// This macro is based on RFC 2046 Section 4.1.2.  Treat any char 0-31
+// except the 9-13 range (\t, \n, \v, \f, \r) and char 27 (used by
+// encodings like Shift_JIS) as non-text
+#define IS_TEXT_CHAR(ch) \
+  (((unsigned char)(ch)) > 31 || (9 <= (ch) && (ch) <= 13) || (ch) == 27)
+
+bool nsUnknownDecoder::LastDitchSniff(nsIRequest* aRequest) {
+  // All we can do now is try to guess whether this is text/plain or
+  // application/octet-stream
+
+  MutexAutoLock lock(mMutex);
+
+  const char* testData;
+  uint32_t testDataLen;
+  if (mDecodedData.IsEmpty()) {
+    testData = mBuffer;
+    // Since some legacy text files end with 0x1A, reading the entire buffer
+    // will lead misdetection.
+    testDataLen = std::min<uint32_t>(mBufferLen, MAX_BUFFER_SIZE);
+  } else {
+    testData = mDecodedData.get();
+    testDataLen = std::min<uint32_t>(mDecodedData.Length(), MAX_BUFFER_SIZE);
+  }
+
+  // First, check for a BOM.  If we see one, assume this is text/plain
+  // in whatever encoding.  If there is a BOM _and_ text we will
+  // always have at least 4 bytes in the buffer (since the 2-byte BOMs
+  // are for 2-byte encodings and the UTF-8 BOM is 3 bytes).
+  if (testDataLen >= 4) {
+    const unsigned char* buf = (const unsigned char*)testData;
+    if ((buf[0] == 0xFE && buf[1] == 0xFF) ||  // UTF-16, Big Endian
+        (buf[0] == 0xFF && buf[1] == 0xFE) ||  // UTF-16 or UCS-4, Little Endian
+        (buf[0] == 0xEF && buf[1] == 0xBB && buf[2] == 0xBF) ||  // UTF-8
+        (buf[0] == 0 && buf[1] == 0 && buf[2] == 0xFE &&
+         buf[3] == 0xFF)) {  // UCS-4, Big Endian
+
+      mContentType = TEXT_PLAIN;
+      return true;
+    }
+  }
+
+  // Now see whether the buffer has any non-text chars.  If not, then let's
+  // just call it text/plain...
+  //
+  uint32_t i;
+  for (i = 0; i < testDataLen && IS_TEXT_CHAR(testData[i]); i++) {
+  }
+
+  if (i == testDataLen) {
+    mContentType = TEXT_PLAIN;
+  } else {
+    mContentType = APPLICATION_OCTET_STREAM;
+  }
+
+  return true;
+}
+
+nsresult nsUnknownDecoder::FireListenerNotifications(nsIRequest* request,
+                                                     nsISupports* aCtxt) {
+  nsresult rv = NS_OK;
+
+  nsCOMPtr<nsIStreamListener> listener;
+  nsAutoCString contentType;
+  {
+    MutexAutoLock lock(mMutex);
+    if (!mNextListener) return NS_ERROR_FAILURE;
+
+    listener = mNextListener;
+    contentType = mContentType;
+  }
+
+  if (!contentType.IsEmpty()) {
+    nsCOMPtr<nsIViewSourceChannel> viewSourceChannel =
+        do_QueryInterface(request);
+    if (viewSourceChannel) {
+      rv = viewSourceChannel->SetOriginalContentType(contentType);
+    } else {
+      nsCOMPtr<nsIChannel> channel = do_QueryInterface(request, &rv);
+      if (NS_SUCCEEDED(rv)) {
+        // Set the new content type on the channel...
+        rv = channel->SetContentType(contentType);
+      }
+    }
+
+    NS_ASSERTION(NS_SUCCEEDED(rv), "Unable to set content type on channel!");
+
+    if (NS_FAILED(rv)) {
+      // Cancel the request to make sure it has the correct status if
+      // mNextListener looks at it.
+      request->Cancel(rv);
+      listener->OnStartRequest(request);
+      return rv;
+    }
+  }
+
+  // Fire the OnStartRequest(...)
+  rv = listener->OnStartRequest(request);
+
+  if (NS_SUCCEEDED(rv)) {
+    // install stream converter if required
+    nsCOMPtr<nsIEncodedChannel> encodedChannel = do_QueryInterface(request);
+    if (encodedChannel) {
+      nsCOMPtr<nsIStreamListener> listenerNew;
+      rv = encodedChannel->DoApplyContentConversions(
+          listener, getter_AddRefs(listenerNew), aCtxt);
+      if (NS_SUCCEEDED(rv) && listenerNew) {
+        MutexAutoLock lock(mMutex);
+        mNextListener = listenerNew;
+        listener = listenerNew;
+      }
+    }
+  }
+
+  if (!mBuffer) return NS_ERROR_OUT_OF_MEMORY;
+
+  // If the request was canceled, then we need to treat that equivalently
+  // to an error returned by OnStartRequest.
+  if (NS_SUCCEEDED(rv)) request->GetStatus(&rv);
+
+  // Fire the first OnDataAvailable for the data that was read from the
+  // stream into the sniffer buffer...
+  if (NS_SUCCEEDED(rv) && (mBufferLen > 0)) {
+    uint32_t len = 0;
+    nsCOMPtr<nsIInputStream> in;
+    nsCOMPtr<nsIOutputStream> out;
+
+    // Create a pipe and fill it with the data from the sniffer buffer.
+    NS_NewPipe(getter_AddRefs(in), getter_AddRefs(out), MAX_BUFFER_SIZE,
+               MAX_BUFFER_SIZE);
+
+    rv = out->Write(mBuffer, mBufferLen, &len);
+    if (NS_SUCCEEDED(rv)) {
+      if (len == mBufferLen) {
+        rv = listener->OnDataAvailable(request, in, 0, len);
+      } else {
+        NS_ERROR("Unable to write all the data into the pipe.");
+        rv = NS_ERROR_FAILURE;
+      }
+    }
+  }
+
+  delete[] mBuffer;
+  mBuffer = nullptr;
+  mBufferLen = 0;
+
+  return rv;
+}
+
+nsresult nsUnknownDecoder::ConvertEncodedData(nsIRequest* request,
+                                              const char* data,
+                                              uint32_t length) {
+  nsresult rv = NS_OK;
+
+  {
+    MutexAutoLock lock(mMutex);
+    mDecodedData = "";
+  }
+  nsCOMPtr<nsIEncodedChannel> encodedChannel(do_QueryInterface(request));
+  if (encodedChannel) {
+    RefPtr<ConvertedStreamListener> strListener =
+        new ConvertedStreamListener(this);
+
+    nsCOMPtr<nsIStreamListener> listener;
+    rv = encodedChannel->DoApplyContentConversions(
+        strListener, getter_AddRefs(listener), nullptr);
+
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+
+    if (listener) {
+      listener->OnStartRequest(request);
+
+      if (length) {
+        nsCOMPtr<nsIStringInputStream> rawStream =
+            do_CreateInstance(NS_STRINGINPUTSTREAM_CONTRACTID);
+        if (!rawStream) return NS_ERROR_FAILURE;
+
+        rv = rawStream->SetData((const char*)data, length);
+        NS_ENSURE_SUCCESS(rv, rv);
+
+        rv = listener->OnDataAvailable(request, rawStream, 0, length);
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      listener->OnStopRequest(request, NS_OK);
+    }
+  }
+  return rv;
+}
+
+//
+// nsIThreadRetargetableStreamListener methods
+//
+NS_IMETHODIMP
+nsUnknownDecoder::CheckListenerChain() {
+  nsCOMPtr<nsIThreadRetargetableStreamListener> listener;
+  {
+    MutexAutoLock lock(mMutex);
+    listener = do_QueryInterface(mNextListener);
+  }
+  if (!listener) {
+    return NS_ERROR_NO_INTERFACE;
+  }
+
+  return listener->CheckListenerChain();
+}
+
+NS_IMETHODIMP
+nsUnknownDecoder::OnDataFinished(nsresult aStatus) {
+  nsCOMPtr<nsIThreadRetargetableStreamListener> listener;
+  {
+    MutexAutoLock lock(mMutex);
+    listener = do_QueryInterface(mNextListener);
+  }
+  if (listener) {
+    return listener->OnDataFinished(aStatus);
+  }
+
+  return NS_OK;
+}
+
+void nsBinaryDetector::DetermineContentType(nsIRequest* aRequest) {
+  nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(aRequest);
+  if (!httpChannel) {
+    return;
+  }
+
+  nsCOMPtr<nsILoadInfo> loadInfo = httpChannel->LoadInfo();
+  if (loadInfo->GetSkipContentSniffing()) {
+    LastDitchSniff(aRequest);
+    return;
+  }
+  // It's an HTTP channel.  Check for the text/plain mess
+  nsAutoCString contentTypeHdr;
+  Unused << httpChannel->GetResponseHeader("Content-Type"_ns, contentTypeHdr);
+  nsAutoCString contentType;
+  httpChannel->GetContentType(contentType);
+
+  // Make sure to do a case-sensitive exact match comparison here.  Apache
+  // 1.x just sends text/plain for "unknown", while Apache 2.x sends
+  // text/plain with a ISO-8859-1 charset.  Debian's Apache version, just to
+  // be different, sends text/plain with iso-8859-1 charset.  For extra fun,
+  // FC7, RHEL4, and Ubuntu Feisty send charset=UTF-8.  Don't do general
+  // case-insensitive comparison, since we really want to apply this crap as
+  // rarely as we can.
+  if (!contentType.EqualsLiteral("text/plain") ||
+      (!contentTypeHdr.EqualsLiteral("text/plain") &&
+       !contentTypeHdr.EqualsLiteral("text/plain; charset=ISO-8859-1") &&
+       !contentTypeHdr.EqualsLiteral("text/plain; charset=iso-8859-1") &&
+       !contentTypeHdr.EqualsLiteral("text/plain; charset=UTF-8"))) {
+    return;
+  }
+
+  // Check whether we have content-encoding.  If we do, don't try to
+  // detect the type.
+  // XXXbz we could improve this by doing a local decompress if we
+  // wanted, I'm sure.
+  nsAutoCString contentEncoding;
+  Unused << httpChannel->GetResponseHeader("Content-Encoding"_ns,
+                                           contentEncoding);
+  if (!contentEncoding.IsEmpty()) {
+    return;
+  }
+
+  LastDitchSniff(aRequest);
+  MutexAutoLock lock(mMutex);
+  if (mContentType.EqualsLiteral(APPLICATION_OCTET_STREAM)) {
+    // We want to guess at it instead
+    mContentType = APPLICATION_GUESS_FROM_EXT;
+  } else {
+    // Let the text/plain type we already have be, so that other content
+    // sniffers can also get a shot at this data.
+    mContentType.Truncate();
+  }
+}
diff --git a/netwerk/streamconv/converters/nsUnknownDecoder.h b/netwerk/streamconv/converters/nsUnknownDecoder.h
new file mode 100644
index 0000000000..3aed80639d
--- /dev/null
+++ b/netwerk/streamconv/converters/nsUnknownDecoder.h
@@ -0,0 +1,150 @@
+/* -*- 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/. */
+
+#ifndef nsUnknownDecoder_h__
+#define nsUnknownDecoder_h__
+
+#include "nsIStreamConverter.h"
+#include "nsIThreadRetargetableStreamListener.h"
+#include "nsIContentSniffer.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/Atomics.h"
+
+#include "nsCOMPtr.h"
+#include "nsString.h"
+
+#define NS_UNKNOWNDECODER_CID                        \
+  { /* 7d7008a0-c49a-11d3-9b22-0080c7cb1080 */       \
+    0x7d7008a0, 0xc49a, 0x11d3, {                    \
+      0x9b, 0x22, 0x00, 0x80, 0xc7, 0xcb, 0x10, 0x80 \
+    }                                                \
+  }
+
+class nsUnknownDecoder : public nsIStreamConverter, public nsIContentSniffer {
+ public:
+  // nsISupports methods
+  NS_DECL_ISUPPORTS
+
+  // nsIStreamConverter methods
+  NS_DECL_NSISTREAMCONVERTER
+
+  // nsIStreamListener methods
+  NS_DECL_NSISTREAMLISTENER
+
+  // nsIRequestObserver methods
+  NS_DECL_NSIREQUESTOBSERVER
+
+  // nsIContentSniffer methods
+  NS_DECL_NSICONTENTSNIFFER
+
+  // nsIThreadRetargetableStreamListener methods
+  NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER
+
+  explicit nsUnknownDecoder(nsIStreamListener* aListener = nullptr);
+
+ protected:
+  virtual ~nsUnknownDecoder();
+
+  virtual void DetermineContentType(nsIRequest* aRequest);
+  nsresult FireListenerNotifications(nsIRequest* request, nsISupports* aCtxt);
+
+  class ConvertedStreamListener : public nsIStreamListener {
+   public:
+    explicit ConvertedStreamListener(nsUnknownDecoder* aDecoder);
+
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIREQUESTOBSERVER
+    NS_DECL_NSISTREAMLISTENER
+
+   private:
+    virtual ~ConvertedStreamListener() = default;
+    static nsresult AppendDataToString(nsIInputStream* inputStream,
+                                       void* closure, const char* rawSegment,
+                                       uint32_t toOffset, uint32_t count,
+                                       uint32_t* writeCount);
+    nsUnknownDecoder* mDecoder;
+  };
+
+ protected:
+  nsCOMPtr<nsIStreamListener> mNextListener;
+
+  // Various sniffer functions.  Returning true means that a type
+  // was determined; false means no luck.
+  bool SniffForHTML(nsIRequest* aRequest);
+  bool SniffForXML(nsIRequest* aRequest);
+
+  // SniffURI guesses at the content type based on the URI (typically
+  // using the extentsion)
+  bool SniffURI(nsIRequest* aRequest);
+
+  // LastDitchSniff guesses at text/plain vs. application/octet-stream
+  // by just looking at whether the data contains null bytes, and
+  // maybe at the fraction of chars with high bit set.  Use this only
+  // as a last-ditch attempt to decide a content type!
+  bool LastDitchSniff(nsIRequest* aRequest);
+
+  /**
+   * An entry struct for our array of sniffers.  Each entry has either
+   * a type associated with it (set these with the SNIFFER_ENTRY macro)
+   * or a function to be executed (set these with the
+   * SNIFFER_ENTRY_WITH_FUNC macro).  The function should take a single
+   * nsIRequest* and returns bool -- true if it sets mContentType,
+   * false otherwise
+   */
+  struct nsSnifferEntry {
+    using TypeSniffFunc = bool (nsUnknownDecoder::*)(nsIRequest*);
+
+    const char* mBytes;
+    uint32_t mByteLen;
+
+    // Exactly one of mMimeType and mContentTypeSniffer should be set non-null
+    const char* mMimeType;
+    TypeSniffFunc mContentTypeSniffer;
+  };
+
+#define SNIFFER_ENTRY(_bytes, _type) \
+  { _bytes, sizeof(_bytes) - 1, _type, nullptr }
+
+#define SNIFFER_ENTRY_WITH_FUNC(_bytes, _func) \
+  { _bytes, sizeof(_bytes) - 1, nullptr, _func }
+
+  static nsSnifferEntry sSnifferEntries[];
+  static uint32_t sSnifferEntryNum;
+
+  // We guarantee in order delivery of OnStart, OnStop and OnData, therefore
+  // we do not need proper locking for mBuffer.
+  mozilla::Atomic<char*> mBuffer;
+  mozilla::Atomic<uint32_t> mBufferLen;
+
+  nsCString mContentType;
+
+  // This mutex syncs: mContentType, mDecodedData and mNextListener.
+  mutable mozilla::Mutex mMutex MOZ_UNANNOTATED;
+
+ protected:
+  nsresult ConvertEncodedData(nsIRequest* request, const char* data,
+                              uint32_t length);
+  nsCString mDecodedData;  // If data are encoded this will be uncompress data.
+};
+
+#define NS_BINARYDETECTOR_CID                        \
+  { /* a2027ec6-ba0d-4c72-805d-148233f5f33c */       \
+    0xa2027ec6, 0xba0d, 0x4c72, {                    \
+      0x80, 0x5d, 0x14, 0x82, 0x33, 0xf5, 0xf3, 0x3c \
+    }                                                \
+  }
+
+/**
+ * Class that detects whether a data stream is text or binary.  This reuses
+ * most of nsUnknownDecoder except the actual content-type determination logic
+ * -- our overridden DetermineContentType simply calls LastDitchSniff and sets
+ * the type to APPLICATION_GUESS_FROM_EXT if the data is detected as binary.
+ */
+class nsBinaryDetector : public nsUnknownDecoder {
+ protected:
+  virtual void DetermineContentType(nsIRequest* aRequest) override;
+};
+
+#endif /* nsUnknownDecoder_h__ */
diff --git a/netwerk/streamconv/moz.build b/netwerk/streamconv/moz.build
new file mode 100644
index 0000000000..e7ef5b95b7
--- /dev/null
+++ b/netwerk/streamconv/moz.build
@@ -0,0 +1,24 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+DIRS += ["converters"]
+
+XPIDL_SOURCES += [
+    "mozITXTToHTMLConv.idl",
+    "nsIDirIndex.idl",
+    "nsIDirIndexListener.idl",
+    "nsIStreamConverter.idl",
+    "nsIStreamConverterService.idl",
+    "nsITXTToHTMLConv.idl",
+]
+
+SOURCES += [
+    "nsStreamConverterService.cpp",
+]
+
+XPIDL_MODULE = "necko_strconv"
+
+FINAL_LIBRARY = "xul"
diff --git a/netwerk/streamconv/mozITXTToHTMLConv.idl b/netwerk/streamconv/mozITXTToHTMLConv.idl
new file mode 100644
index 0000000000..5a2a1510c9
--- /dev/null
+++ b/netwerk/streamconv/mozITXTToHTMLConv.idl
@@ -0,0 +1,88 @@
+/* -*- 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/. */
+
+/**
+  Description: Currently only functions to enhance plain text with HTML tags.
+  <p>
+  Wrapper class for various parsing routines, that convert plain text to HTML.
+  They try to recognize cites, URLs, plain text formattting like *bold* etc.
+  See <http://www.bucksch.org/1/projects/mozilla/16507/> for a description.
+ */
+
+#include "nsIStreamConverter.idl"
+
+%{C++
+// {77c0e42a-1dd2-11b2-8ebf-edc6606f2f4b}
+#define MOZITXTTOHTMLCONV_CID \
+    { 0x77c0e42a, 0x1dd2, 0x11b2, \
+    { 0x8e, 0xbf, 0xed, 0xc6, 0x60, 0x6f, 0x2f, 0x4b } }
+
+#define MOZ_TXTTOHTMLCONV_CONTRACTID \
+  "@mozilla.org/txttohtmlconv;1"
+
+%}
+
+[scriptable, uuid(77c0e42a-1dd2-11b2-8ebf-edc6606f2f4b)]
+interface mozITXTToHTMLConv : nsIStreamConverter {
+  const unsigned long kEntities = 0;  // just convert < & > to &lt; &amp; and &gt;
+  const unsigned long kURLs = 1 << 1;
+  const unsigned long kGlyphSubstitution = 1 << 2;  // Smilies, &reg; etc.
+  const unsigned long kStructPhrase = 1 << 3;       // E.g. *bold* -> <strong>
+
+/**
+  @param text: plain text to scan. May be a line, paragraph (recommended)
+               or just a substring.<p>
+               Must be non-escaped, pure unicode.<p>
+               <em>Note:</em> ScanTXT(a, o) + ScanTXT(b, o) may be !=
+               Scan(a + b, o)
+  @param whattodo: Bitfield describing the modes of operation
+  @result      "<", ">" and "&" are escaped and HTML tags are inserted where
+               appropriate.
+ */
+  AString   scanTXT(in AString text, in unsigned long whattodo);
+
+/**
+  Adds additional formatting to user edited text, that the user was too lazy
+  or "unknowledged" (DELETEME: is that a word?) to make.
+  <p>
+  <em>Note:</em> Don't use kGlyphSubstitution with this function. This option
+  generates tags, that are unuseable for UAs other than Mozilla. This would
+  be a data loss bug.
+
+  @param text: HTML source to scan. May be a line, paragraph (recommended)
+               or just a substring.<p>
+               Must be correct HTML. "<", ">" and "&" must be escaped,
+               other chars must be pure unicode.<p>
+               <em>Note:</em> ScanTXT(a, o) + ScanTXT(b, o) may be !=
+               Scan(a + b, o)
+  @param whattodo: Bitfield describing the modes of operation
+  @result      Additional HTML tags are inserted where appropriate.
+ */
+  AString   scanHTML(in AString text, in unsigned long whattodo);
+
+/**
+  @param line: line in original msg, possibly starting starting with
+               txt quote tags like ">"
+  @param logLineStart: pos in line, where the real content (logical line)
+               begins, i.e. pos after all txt quote tags.
+               E.g. position of "t" in "> > text".
+               Initial value must be 0, unless line is not real line.
+  @return      Cite Level, i.e. number of txt quote tags found, i.e. number of
+               nested quotes.
+ */
+  unsigned long   citeLevelTXT(in wstring line,
+                               out unsigned long logLineStart);
+
+/**
+ @param a wide string to scan for the presence of a URL.
+ @param aLength --> the length of the buffer to be scanned
+ @param aPos --> the position in the buffer to start scanning for a url
+
+ aStartPos --> index into the start of a url (-1 if no url found)
+ aEndPos --> index of the last character in the url (-1 if no url found)
+ */
+
+  void findURLInPlaintext(in wstring text, in long aLength, in long aPos, out long aStartPos, out long aEndPos);
+};
diff --git a/netwerk/streamconv/nsIDirIndex.idl b/netwerk/streamconv/nsIDirIndex.idl
new file mode 100644
index 0000000000..6f1df669a0
--- /dev/null
+++ b/netwerk/streamconv/nsIDirIndex.idl
@@ -0,0 +1,59 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsISupports.idl"
+
+/** A class holding information about a directory index.
+ * These have no reference back to their original source -
+ * changing these attributes won't affect the directory
+ */
+[scriptable, uuid(23bbabd0-1dd2-11b2-86b7-aad68ae7d7e0)]
+interface nsIDirIndex : nsISupports
+{
+    /**
+     * Entry's type is unknown
+     */
+    const unsigned long TYPE_UNKNOWN = 0;
+
+    /**
+     * Entry is a directory
+     */
+    const unsigned long TYPE_DIRECTORY = 1;
+
+    /**
+     * Entry is a file
+     */
+    const unsigned long TYPE_FILE = 2;
+
+    /**
+     * Entry is a symlink
+     */
+    const unsigned long TYPE_SYMLINK = 3;
+
+    /**
+     * The type of the entry - one of the constants above
+     */
+    attribute unsigned long type;
+
+    /**
+     * The fully qualified filename, expressed as a uri
+     *
+     * This is encoded with the encoding specified in
+     * the nsIDirIndexParser, and is also escaped.
+     */
+    attribute ACString location;
+
+    /**
+     * File size, with -1 meaning "unknown"
+     */
+    attribute long long size;
+
+    /**
+     * Last-modified time in seconds-since-epoch.
+     * -1 means unknown - this is valid, because there were no
+     * ftp servers in 1969
+     */
+    attribute PRTime lastModified;
+};
diff --git a/netwerk/streamconv/nsIDirIndexListener.idl b/netwerk/streamconv/nsIDirIndexListener.idl
new file mode 100644
index 0000000000..ba248b5e75
--- /dev/null
+++ b/netwerk/streamconv/nsIDirIndexListener.idl
@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsIStreamListener.idl"
+
+interface nsIDirIndex;
+
+/**
+ * This interface is used to receive contents of directory index listings
+ * from a protocol. They can then be transformed into an output format
+ * (such as rdf, html, etc)
+ */
+[scriptable, uuid(fae4e9a8-1dd1-11b2-b53c-8f3aa1bbf8f5)]
+interface nsIDirIndexListener : nsISupports {
+    /**
+     * Called for each directory entry
+     *
+     * @param request - the request
+     * @param index - new index to add
+     */
+    void onIndexAvailable(in nsIRequest aRequest,
+                          in nsIDirIndex aIndex);
+};
+
+/**
+ * A parser for application/http-index-format
+ */
+[scriptable, uuid(38e3066c-1dd2-11b2-9b59-8be515c1ee3f)]
+interface nsIDirIndexParser : nsIStreamListener {
+    /**
+     * The interface to use as a callback for new entries
+     */
+    attribute nsIDirIndexListener listener;
+};
diff --git a/netwerk/streamconv/nsIStreamConverter.idl b/netwerk/streamconv/nsIStreamConverter.idl
new file mode 100644
index 0000000000..68f341b328
--- /dev/null
+++ b/netwerk/streamconv/nsIStreamConverter.idl
@@ -0,0 +1,113 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsIThreadRetargetableStreamListener.idl"
+
+interface nsIChannel;
+interface nsIInputStream;
+
+/**
+ * nsIStreamConverter provides an interface to implement when you have code
+ * that converts data from one type to another.
+ *
+ * Suppose you had code that converted plain text into HTML. You could implement
+ * this interface to allow everyone else to use your conversion logic using a
+ * standard api.
+ * <p>
+ * <b>STREAM CONVERTER USERS</b>
+ *
+ * There are currently two ways to use a stream converter:
+ * <ol>
+ * <li> <b>SYNCHRONOUS</b> Stream to Stream
+ *    You can supply the service with a stream of type X
+ *    and it will convert it to your desired output type and return
+ *    a converted (blocking) stream to you.</li>
+ *
+ * <li> <b>ASYNCHRONOUS</b> nsIStreamListener to nsIStreamListener
+ *    You can supply data directly to the converter by calling it's
+ *    nsIStreamListener::OnDataAvailable() method. It will then
+ *    convert that data from type X to your desired output type and
+ *    return converted data to you via the nsIStreamListener you passed
+ *    in by calling its OnDataAvailable() method.</li>
+ * </ol>
+ * <p>
+ *
+ * <b>STREAM CONVERTER SUPPLIERS</b>
+ *
+ * Registering a stream converter:
+ * Stream converter registration is a two step process. First of all the stream
+ * converter implementation must register itself with the component manager using
+ * a contractid in the format below. Second, the stream converter must add the contractid
+ * to the registry.
+ *
+ * Stream converter contractid format (the stream converter root key is defined in this
+ * file):
+ *
+ * <pre>@mozilla.org/streamconv;1?from=FROM_MIME_TYPE&to=TO_MIME_TYPE</pre>
+ *
+ * @author Jud Valeski
+ * @see nsIStreamConverterService
+ */
+
+[scriptable, uuid(0b6e2c69-5cf5-48b0-9dfd-c95950e2cc7b)]
+interface nsIStreamConverter : nsIThreadRetargetableStreamListener {
+
+    /**
+     * <b>SYNCRONOUS VERSION</b>
+     * Converts a stream of one type, to a stream of another type.
+     *
+     * Use this method when you have a stream you want to convert.
+     *
+     * @param aFromStream   The stream representing the original/raw data.
+     * @param aFromType     The MIME type of aFromStream.
+     * @param aToType       The MIME type of the returned stream.
+     * @param aCtxt         Either an opaque context, or a converter specific context
+     *                      (implementation specific).
+     * @return              The converted stream. NOTE: The returned stream may not
+     *                      already be converted. An efficient stream converter
+     *                      implementation will converter data on demand rather than
+     *                      buffering the converted data until it is used.
+     */
+    nsIInputStream convert(in nsIInputStream aFromStream,
+                           in string aFromType,
+                           in string aToType,
+                           in nsISupports aCtxt);
+
+    /**
+     * <b>ASYNCRONOUS VERSION</b>
+     * Converts data arriving via the converter's nsIStreamListener::OnDataAvailable()
+     * method from one type to another, pushing the converted data out to the caller
+     * via aListener::OnDataAvailable().
+     *
+     * Use this method when you want to proxy (and convert) nsIStreamListener callbacks
+     * asynchronously.
+     *
+     * @param aFromType     The MIME type of the original/raw data.
+     * @param aToType       The MIME type of the converted data.
+     * @param aListener     The listener who receives the converted data.
+     * @param aCtxt         Either an opaque context, or a converter specific context
+     *                      (implementation specific).
+     */
+    void asyncConvertData(in string aFromType,
+                          in string aToType,
+                          in nsIStreamListener aListener,
+                          in nsISupports aCtxt);
+
+    /**
+     * Returns the content type that the stream listener passed to asyncConvertData will
+     * see on the channel if the conversion is being done from aFromType to * /*.
+     *
+     * @param aFromType     The type of the content prior to conversion.
+     * @param aChannel      The channel that we'd like to convert. May be null.
+     *
+     * @throws if the converter does not support conversion to * /* or if it doesn't know
+     *         the type in advance.
+     */
+    ACString getConvertedType(in ACString aFromType, in nsIChannel aChannel);
+};
+
+%{C++
+#define NS_ISTREAMCONVERTER_KEY         "@mozilla.org/streamconv;1"
+%}
diff --git a/netwerk/streamconv/nsIStreamConverterService.idl b/netwerk/streamconv/nsIStreamConverterService.idl
new file mode 100644
index 0000000000..f3bc0931ac
--- /dev/null
+++ b/netwerk/streamconv/nsIStreamConverterService.idl
@@ -0,0 +1,89 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsISupports.idl"
+
+interface nsIChannel;
+interface nsIInputStream;
+interface nsIStreamListener;
+
+%{C++
+#define NS_ISTREAMCONVERTER_KEY         "@mozilla.org/streamconv;1"
+%}
+
+/**
+ * The nsIStreamConverterService is a higher level stream converter factory
+ * responsible for locating and creating stream converters
+ * (nsIStreamConverter).
+ *
+ * This service retrieves an interface that can convert data from a particular
+ * MIME type, to a particular MIME type. It is responsible for any intermediary
+ * conversion required in order to get from X to Z, assuming direct conversion
+ * is not possible.
+ *
+ * @author Jud Valeski
+ * @see nsIStreamConverter
+ */
+[scriptable, uuid(f2b1ab53-f0bd-4adb-9365-e59b1701a258)]
+interface nsIStreamConverterService : nsISupports {
+    /**
+     * Tests whether conversion between the two specified types is possible.
+     * This is cheaper than calling convert()/asyncConvertData(); it is not
+     * necessary to call this function before calling one of those, though.
+     */
+    boolean canConvert(in string aFromType, in string aToType);
+
+    /**
+     * Returns the content type that will be returned from a converter
+     * created with aFromType and  * /*.
+     * Can fail if no converters support this conversion, or if the
+     * output type isn't known in advance.
+     */
+    ACString convertedType(in ACString aFromType, in nsIChannel aChannel);
+
+    /**
+     * <b>SYNCHRONOUS VERSION</b>
+     * Converts a stream of one type, to a stream of another type.
+     *
+     * Use this method when you have a stream you want to convert.
+     *
+     * @param aFromStream   The stream representing the original/raw data.
+     * @param aFromType     The MIME type of aFromStream.
+     * @param aToType       The MIME type of the returned stream.
+     * @param aContext      Either an opaque context, or a converter specific
+     *                      context (implementation specific).
+     * @return              The converted stream. NOTE: The returned stream
+     *                      may not already be converted. An efficient stream
+     *                      converter implementation will convert data on
+     *                      demand rather than buffering the converted data
+     *                      until it is used.
+     */
+    nsIInputStream convert(in nsIInputStream aFromStream,
+                           in string aFromType,
+                           in string aToType,
+                           in nsISupports aContext);
+
+    /**
+     * <b>ASYNCHRONOUS VERSION</b>
+     * Retrieves a nsIStreamListener that receives the original/raw data via its
+     * nsIStreamListener::OnDataAvailable() callback, then converts and pushes
+     * the data to aListener.
+     *
+     * Use this method when you want to proxy (and convert) nsIStreamListener
+     * callbacks asynchronously.
+     *
+     * @param aFromType     The MIME type of the original/raw data.
+     * @param aToType       The MIME type of the converted data.
+     * @param aListener     The listener that receives the converted data.
+     * @param aCtxt         Either an opaque context, or a converter specific
+     *                      context (implementation specific).
+     * @return              A nsIStreamListener that receives data via its
+     *                      OnDataAvailable() method.
+     */
+    nsIStreamListener asyncConvertData(in string aFromType,
+                                       in string aToType,
+                                       in nsIStreamListener aListener,
+                                       in nsISupports aContext);
+};
diff --git a/netwerk/streamconv/nsITXTToHTMLConv.idl b/netwerk/streamconv/nsITXTToHTMLConv.idl
new file mode 100644
index 0000000000..bfe841834d
--- /dev/null
+++ b/netwerk/streamconv/nsITXTToHTMLConv.idl
@@ -0,0 +1,25 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsIStreamConverter.idl"
+
+[scriptable, uuid(933355f6-1dd2-11b2-a9b0-d335b9e35983)]
+interface nsITXTToHTMLConv : nsIStreamConverter {
+  /**
+   * @param text: Title to set for the HTML document.  Only applicable if
+   *              preFormatHTML(true) is called.
+   * @result      The given title will be used to form an HTML document
+   *              from the plain text document.
+   */
+  void      setTitle(in wstring text);
+
+  /**
+   * @param value: true to use an HTML header and footer on the document,
+   *               false to omit it.
+   * @result       The document will use a header and footer if value is
+   *               true.
+   */
+  void      preFormatHTML(in boolean value);
+};
diff --git a/netwerk/streamconv/nsStreamConverterService.cpp b/netwerk/streamconv/nsStreamConverterService.cpp
new file mode 100644
index 0000000000..ce95bb0404
--- /dev/null
+++ b/netwerk/streamconv/nsStreamConverterService.cpp
@@ -0,0 +1,543 @@
+/* -*- 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 "nsComponentManagerUtils.h"
+#include "nsStreamConverterService.h"
+#include "nsIComponentRegistrar.h"
+#include "nsString.h"
+#include "nsAtom.h"
+#include "nsDeque.h"
+#include "nsIInputStream.h"
+#include "nsIStreamConverter.h"
+#include "nsICategoryManager.h"
+#include "nsXPCOM.h"
+#include "nsISupportsPrimitives.h"
+#include "nsTArray.h"
+#include "nsServiceManagerUtils.h"
+#include "nsISimpleEnumerator.h"
+#include "mozilla/UniquePtr.h"
+
+///////////////////////////////////////////////////////////////////
+// Breadth-First-Search (BFS) algorithm state classes and types.
+
+// Used to establish discovered verticies.
+enum BFScolors { white, gray, black };
+
+// BFS hashtable data class.
+struct BFSTableData {
+  nsCString key;
+  BFScolors color;
+  int32_t distance;
+  mozilla::UniquePtr<nsCString> predecessor;
+
+  explicit BFSTableData(const nsACString& aKey)
+      : key(aKey), color(white), distance(-1) {}
+};
+
+////////////////////////////////////////////////////////////
+// nsISupports methods
+NS_IMPL_ISUPPORTS(nsStreamConverterService, nsIStreamConverterService)
+
+////////////////////////////////////////////////////////////
+// nsIStreamConverterService methods
+
+////////////////////////////////////////////////////////////
+// nsStreamConverterService methods
+
+// Builds the graph represented as an adjacency list (and built up in
+// memory using an nsObjectHashtable and nsCOMArray combination).
+//
+// :BuildGraph() consults the category manager for all stream converter
+// CONTRACTIDS then fills the adjacency list with edges.
+// An edge in this case is comprised of a FROM and TO MIME type combination.
+//
+// CONTRACTID format:
+// @mozilla.org/streamconv;1?from=text/html&to=text/plain
+// XXX curently we only handle a single from and to combo, we should repeat the
+// XXX registration process for any series of from-to combos.
+// XXX can use nsTokenizer for this.
+//
+
+nsresult nsStreamConverterService::BuildGraph() {
+  nsresult rv;
+
+  nsCOMPtr<nsICategoryManager> catmgr(
+      do_GetService(NS_CATEGORYMANAGER_CONTRACTID, &rv));
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsISimpleEnumerator> entries;
+  rv = catmgr->EnumerateCategory(NS_ISTREAMCONVERTER_KEY,
+                                 getter_AddRefs(entries));
+  if (NS_FAILED(rv)) return rv;
+
+  // go through each entry to build the graph
+  nsCOMPtr<nsISupports> supports;
+  nsCOMPtr<nsISupportsCString> entry;
+  rv = entries->GetNext(getter_AddRefs(supports));
+  while (NS_SUCCEEDED(rv)) {
+    entry = do_QueryInterface(supports);
+
+    // get the entry string
+    nsAutoCString entryString;
+    rv = entry->GetData(entryString);
+    if (NS_FAILED(rv)) return rv;
+
+    // cobble the entry string w/ the converter key to produce a full
+    // contractID.
+    nsAutoCString contractID(NS_ISTREAMCONVERTER_KEY);
+    contractID.Append(entryString);
+
+    // now we've got the CONTRACTID, let's parse it up.
+    rv = AddAdjacency(contractID.get());
+    if (NS_FAILED(rv)) return rv;
+
+    rv = entries->GetNext(getter_AddRefs(supports));
+  }
+
+  return NS_OK;
+}
+
+// XXX currently you can not add the same adjacency (i.e. you can't have
+// multiple
+// XXX stream converters registering to handle the same from-to combination.
+// It's
+// XXX not programatically prohibited, it's just that results are un-predictable
+// XXX right now.
+nsresult nsStreamConverterService::AddAdjacency(const char* aContractID) {
+  nsresult rv;
+  // first parse out the FROM and TO MIME-types.
+
+  nsAutoCString fromStr, toStr;
+  rv = ParseFromTo(aContractID, fromStr, toStr);
+  if (NS_FAILED(rv)) return rv;
+
+  // Each MIME-type is a vertex in the graph, so first lets make sure
+  // each MIME-type is represented as a key in our hashtable.
+
+  nsTArray<RefPtr<nsAtom>>* const fromEdges =
+      mAdjacencyList.GetOrInsertNew(fromStr);
+
+  mAdjacencyList.GetOrInsertNew(toStr);
+
+  // Now we know the FROM and TO types are represented as keys in the hashtable.
+  // Let's "connect" the verticies, making an edge.
+
+  RefPtr<nsAtom> vertex = NS_Atomize(toStr);
+  if (!vertex) return NS_ERROR_OUT_OF_MEMORY;
+
+  NS_ASSERTION(fromEdges, "something wrong in adjacency list construction");
+  if (!fromEdges) return NS_ERROR_FAILURE;
+
+  // XXX(Bug 1631371) Check if this should use a fallible operation as it
+  // pretended earlier.
+  fromEdges->AppendElement(vertex);
+  return NS_OK;
+}
+
+nsresult nsStreamConverterService::ParseFromTo(const char* aContractID,
+                                               nsCString& aFromRes,
+                                               nsCString& aToRes) {
+  nsAutoCString ContractIDStr(aContractID);
+
+  int32_t fromLoc = ContractIDStr.Find("from=");
+  int32_t toLoc = ContractIDStr.Find("to=");
+  if (-1 == fromLoc || -1 == toLoc) return NS_ERROR_FAILURE;
+
+  fromLoc = fromLoc + 5;
+  toLoc = toLoc + 3;
+
+  nsAutoCString fromStr, toStr;
+
+  ContractIDStr.Mid(fromStr, fromLoc, toLoc - 4 - fromLoc);
+  ContractIDStr.Mid(toStr, toLoc, ContractIDStr.Length() - toLoc);
+
+  aFromRes.Assign(fromStr);
+  aToRes.Assign(toStr);
+
+  return NS_OK;
+}
+
+using BFSHashTable = nsClassHashtable<nsCStringHashKey, BFSTableData>;
+
+// nsObjectHashtable enumerator functions.
+
+class CStreamConvDeallocator : public nsDequeFunctor<nsCString> {
+ public:
+  void operator()(nsCString* anObject) override { delete anObject; }
+};
+
+// walks the graph using a breadth-first-search algorithm which generates a
+// discovered verticies tree. This tree is then walked up (from destination
+// vertex, to origin vertex) and each link in the chain is added to an
+// nsStringArray. A direct lookup for the given CONTRACTID should be made prior
+// to calling this method in an attempt to find a direct converter rather than
+// walking the graph.
+nsresult nsStreamConverterService::FindConverter(
+    const char* aContractID, nsTArray<nsCString>** aEdgeList) {
+  nsresult rv;
+  if (!aEdgeList) return NS_ERROR_NULL_POINTER;
+  *aEdgeList = nullptr;
+
+  // walk the graph in search of the appropriate converter.
+
+  uint32_t vertexCount = mAdjacencyList.Count();
+  if (0 >= vertexCount) return NS_ERROR_FAILURE;
+
+  // Create a corresponding color table for each vertex in the graph.
+  BFSHashTable lBFSTable;
+  for (const auto& entry : mAdjacencyList) {
+    const nsACString& key = entry.GetKey();
+    MOZ_ASSERT(entry.GetWeak(), "no data in the table iteration");
+    lBFSTable.InsertOrUpdate(key, mozilla::MakeUnique<BFSTableData>(key));
+  }
+
+  NS_ASSERTION(lBFSTable.Count() == vertexCount,
+               "strmconv BFS table init problem");
+
+  // This is our source vertex; our starting point.
+  nsAutoCString fromC, toC;
+  rv = ParseFromTo(aContractID, fromC, toC);
+  if (NS_FAILED(rv)) return rv;
+
+  BFSTableData* data = lBFSTable.Get(fromC);
+  if (!data) {
+    return NS_ERROR_FAILURE;
+  }
+
+  data->color = gray;
+  data->distance = 0;
+  auto* dtorFunc = new CStreamConvDeallocator();
+
+  nsDeque grayQ(dtorFunc);
+
+  // Now generate the shortest path tree.
+  grayQ.Push(new nsCString(fromC));
+  while (0 < grayQ.GetSize()) {
+    nsCString* currentHead = (nsCString*)grayQ.PeekFront();
+    nsTArray<RefPtr<nsAtom>>* data2 = mAdjacencyList.Get(*currentHead);
+    if (!data2) return NS_ERROR_FAILURE;
+
+    // Get the state of the current head to calculate the distance of each
+    // reachable vertex in the loop.
+    BFSTableData* headVertexState = lBFSTable.Get(*currentHead);
+    if (!headVertexState) return NS_ERROR_FAILURE;
+
+    int32_t edgeCount = data2->Length();
+
+    for (int32_t i = 0; i < edgeCount; i++) {
+      nsAtom* curVertexAtom = data2->ElementAt(i);
+      auto* curVertex = new nsCString();
+      curVertexAtom->ToUTF8String(*curVertex);
+
+      BFSTableData* curVertexState = lBFSTable.Get(*curVertex);
+      if (!curVertexState) {
+        delete curVertex;
+        return NS_ERROR_FAILURE;
+      }
+
+      if (white == curVertexState->color) {
+        curVertexState->color = gray;
+        curVertexState->distance = headVertexState->distance + 1;
+        curVertexState->predecessor =
+            mozilla::MakeUnique<nsCString>(*currentHead);
+        grayQ.Push(curVertex);
+      } else {
+        delete curVertex;  // if this vertex has already been discovered, we
+                           // don't want to leak it. (non-discovered vertex's
+                           // get cleaned up when they're popped).
+      }
+    }
+    headVertexState->color = black;
+    nsCString* cur = (nsCString*)grayQ.PopFront();
+    delete cur;
+    cur = nullptr;
+  }
+  // The shortest path (if any) has been generated and is represented by the
+  // chain of BFSTableData->predecessor keys. Start at the bottom and work our
+  // way up.
+
+  // first parse out the FROM and TO MIME-types being registered.
+
+  nsAutoCString fromStr, toMIMEType;
+  rv = ParseFromTo(aContractID, fromStr, toMIMEType);
+  if (NS_FAILED(rv)) return rv;
+
+  // get the root CONTRACTID
+  nsAutoCString ContractIDPrefix(NS_ISTREAMCONVERTER_KEY);
+  auto* shortestPath = new nsTArray<nsCString>();
+
+  data = lBFSTable.Get(toMIMEType);
+  if (!data) {
+    // If this vertex isn't in the BFSTable, then no-one has registered for it,
+    // therefore we can't do the conversion.
+    delete shortestPath;
+    return NS_ERROR_FAILURE;
+  }
+
+  while (data) {
+    if (fromStr.Equals(data->key)) {
+      // found it. We're done here.
+      *aEdgeList = shortestPath;
+      return NS_OK;
+    }
+
+    // reconstruct the CONTRACTID.
+    // Get the predecessor.
+    if (!data->predecessor) break;  // no predecessor
+    BFSTableData* predecessorData = lBFSTable.Get(*data->predecessor);
+
+    if (!predecessorData) break;  // no predecessor, chain doesn't exist.
+
+    // build out the CONTRACTID.
+    nsAutoCString newContractID(ContractIDPrefix);
+    newContractID.AppendLiteral("?from=");
+
+    newContractID.Append(predecessorData->key);
+
+    newContractID.AppendLiteral("&to=");
+    newContractID.Append(data->key);
+
+    // Add this CONTRACTID to the chain.
+    // XXX(Bug 1631371) Check if this should use a fallible operation as it
+    // pretended earlier.
+    shortestPath->AppendElement(newContractID);
+
+    // move up the tree.
+    data = predecessorData;
+  }
+  delete shortestPath;
+  return NS_ERROR_FAILURE;  // couldn't find a stream converter or chain.
+}
+
+/////////////////////////////////////////////////////
+// nsIStreamConverterService methods
+NS_IMETHODIMP
+nsStreamConverterService::CanConvert(const char* aFromType, const char* aToType,
+                                     bool* _retval) {
+  nsCOMPtr<nsIComponentRegistrar> reg;
+  nsresult rv = NS_GetComponentRegistrar(getter_AddRefs(reg));
+  if (NS_FAILED(rv)) return rv;
+
+  nsAutoCString contractID;
+  contractID.AssignLiteral(NS_ISTREAMCONVERTER_KEY "?from=");
+  contractID.Append(aFromType);
+  contractID.AppendLiteral("&to=");
+  contractID.Append(aToType);
+
+  // See if we have a direct match
+  rv = reg->IsContractIDRegistered(contractID.get(), _retval);
+  if (NS_FAILED(rv)) return rv;
+  if (*_retval) return NS_OK;
+
+  // Otherwise try the graph.
+  rv = BuildGraph();
+  if (NS_FAILED(rv)) return rv;
+
+  nsTArray<nsCString>* converterChain = nullptr;
+  rv = FindConverter(contractID.get(), &converterChain);
+  *_retval = NS_SUCCEEDED(rv);
+
+  delete converterChain;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsStreamConverterService::ConvertedType(const nsACString& aFromType,
+                                        nsIChannel* aChannel,
+                                        nsACString& aOutToType) {
+  // first determine whether we can even handle this conversion
+  // build a CONTRACTID
+  nsAutoCString contractID;
+  contractID.AssignLiteral(NS_ISTREAMCONVERTER_KEY "?from=");
+  contractID.Append(aFromType);
+  contractID.AppendLiteral("&to=*/*");
+  const char* cContractID = contractID.get();
+
+  nsresult rv;
+  nsCOMPtr<nsIStreamConverter> converter(do_CreateInstance(cContractID, &rv));
+  if (NS_SUCCEEDED(rv)) {
+    return converter->GetConvertedType(aFromType, aChannel, aOutToType);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP
+nsStreamConverterService::Convert(nsIInputStream* aFromStream,
+                                  const char* aFromType, const char* aToType,
+                                  nsISupports* aContext,
+                                  nsIInputStream** _retval) {
+  if (!aFromStream || !aFromType || !aToType || !_retval) {
+    return NS_ERROR_NULL_POINTER;
+  }
+  nsresult rv;
+
+  // first determine whether we can even handle this conversion
+  // build a CONTRACTID
+  nsAutoCString contractID;
+  contractID.AssignLiteral(NS_ISTREAMCONVERTER_KEY "?from=");
+  contractID.Append(aFromType);
+  contractID.AppendLiteral("&to=");
+  contractID.Append(aToType);
+  const char* cContractID = contractID.get();
+
+  nsCOMPtr<nsIStreamConverter> converter(do_CreateInstance(cContractID, &rv));
+  if (NS_FAILED(rv)) {
+    // couldn't go direct, let's try walking the graph of converters.
+    rv = BuildGraph();
+    if (NS_FAILED(rv)) return rv;
+
+    nsTArray<nsCString>* converterChain = nullptr;
+
+    rv = FindConverter(cContractID, &converterChain);
+    if (NS_FAILED(rv)) {
+      // can't make this conversion.
+      // XXX should have a more descriptive error code.
+      return NS_ERROR_FAILURE;
+    }
+
+    int32_t edgeCount = int32_t(converterChain->Length());
+    NS_ASSERTION(edgeCount > 0, "findConverter should have failed");
+
+    // convert the stream using each edge of the graph as a step.
+    // this is our stream conversion traversal.
+    nsCOMPtr<nsIInputStream> dataToConvert = aFromStream;
+    nsCOMPtr<nsIInputStream> convertedData;
+
+    for (int32_t i = edgeCount - 1; i >= 0; i--) {
+      const char* lContractID = converterChain->ElementAt(i).get();
+
+      converter = do_CreateInstance(lContractID, &rv);
+
+      if (NS_FAILED(rv)) {
+        delete converterChain;
+        return rv;
+      }
+
+      nsAutoCString fromStr, toStr;
+      rv = ParseFromTo(lContractID, fromStr, toStr);
+      if (NS_FAILED(rv)) {
+        delete converterChain;
+        return rv;
+      }
+
+      rv = converter->Convert(dataToConvert, fromStr.get(), toStr.get(),
+                              aContext, getter_AddRefs(convertedData));
+      dataToConvert = convertedData;
+      if (NS_FAILED(rv)) {
+        delete converterChain;
+        return rv;
+      }
+    }
+
+    delete converterChain;
+    convertedData.forget(_retval);
+  } else {
+    // we're going direct.
+    rv = converter->Convert(aFromStream, aFromType, aToType, aContext, _retval);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsStreamConverterService::AsyncConvertData(const char* aFromType,
+                                           const char* aToType,
+                                           nsIStreamListener* aListener,
+                                           nsISupports* aContext,
+                                           nsIStreamListener** _retval) {
+  if (!aFromType || !aToType || !aListener || !_retval) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  nsresult rv;
+
+  // first determine whether we can even handle this conversion
+  // build a CONTRACTID
+  nsAutoCString contractID;
+  contractID.AssignLiteral(NS_ISTREAMCONVERTER_KEY "?from=");
+  contractID.Append(aFromType);
+  contractID.AppendLiteral("&to=");
+  contractID.Append(aToType);
+  const char* cContractID = contractID.get();
+
+  nsCOMPtr<nsIStreamConverter> listener(do_CreateInstance(cContractID, &rv));
+  if (NS_FAILED(rv)) {
+    // couldn't go direct, let's try walking the graph of converters.
+    rv = BuildGraph();
+    if (NS_FAILED(rv)) return rv;
+
+    nsTArray<nsCString>* converterChain = nullptr;
+
+    rv = FindConverter(cContractID, &converterChain);
+    if (NS_FAILED(rv)) {
+      // can't make this conversion.
+      // XXX should have a more descriptive error code.
+      return NS_ERROR_FAILURE;
+    }
+
+    // aListener is the listener that wants the final, converted, data.
+    // we initialize finalListener w/ aListener so it gets put at the
+    // tail end of the chain, which in the loop below, means the *first*
+    // converter created.
+    nsCOMPtr<nsIStreamListener> finalListener = aListener;
+
+    // convert the stream using each edge of the graph as a step.
+    // this is our stream conversion traversal.
+    int32_t edgeCount = int32_t(converterChain->Length());
+    NS_ASSERTION(edgeCount > 0, "findConverter should have failed");
+    for (int i = 0; i < edgeCount; i++) {
+      const char* lContractID = converterChain->ElementAt(i).get();
+
+      // create the converter for this from/to pair
+      nsCOMPtr<nsIStreamConverter> converter(do_CreateInstance(lContractID));
+      NS_ASSERTION(converter,
+                   "graph construction problem, built a contractid that wasn't "
+                   "registered");
+
+      nsAutoCString fromStr, toStr;
+      rv = ParseFromTo(lContractID, fromStr, toStr);
+      if (NS_FAILED(rv)) {
+        delete converterChain;
+        return rv;
+      }
+
+      // connect the converter w/ the listener that should get the converted
+      // data.
+      rv = converter->AsyncConvertData(fromStr.get(), toStr.get(),
+                                       finalListener, aContext);
+      if (NS_FAILED(rv)) {
+        delete converterChain;
+        return rv;
+      }
+
+      // the last iteration of this loop will result in finalListener
+      // pointing to the converter that "starts" the conversion chain.
+      // this converter's "from" type is the original "from" type. Prior
+      // to the last iteration, finalListener will continuously be wedged
+      // into the next listener in the chain, then be updated.
+      finalListener = converter;
+    }
+    delete converterChain;
+    // return the first listener in the chain.
+    finalListener.forget(_retval);
+  } else {
+    // we're going direct.
+    rv = listener->AsyncConvertData(aFromType, aToType, aListener, aContext);
+    listener.forget(_retval);
+  }
+
+  return rv;
+}
+
+nsresult NS_NewStreamConv(nsStreamConverterService** aStreamConv) {
+  MOZ_ASSERT(aStreamConv != nullptr, "null ptr");
+  if (!aStreamConv) return NS_ERROR_NULL_POINTER;
+
+  RefPtr<nsStreamConverterService> conv = new nsStreamConverterService();
+  conv.forget(aStreamConv);
+
+  return NS_OK;
+}
diff --git a/netwerk/streamconv/nsStreamConverterService.h b/netwerk/streamconv/nsStreamConverterService.h
new file mode 100644
index 0000000000..0d402c5657
--- /dev/null
+++ b/netwerk/streamconv/nsStreamConverterService.h
@@ -0,0 +1,46 @@
+/* -*- Mode: C++; tab-width: 4; 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 __nsstreamconverterservice__h___
+#define __nsstreamconverterservice__h___
+
+#include "nsIStreamConverterService.h"
+
+#include "nsClassHashtable.h"
+#include "nsStringFwd.h"
+#include "nsTArrayForwardDeclare.h"
+
+class nsAtom;
+
+class nsStreamConverterService : public nsIStreamConverterService {
+ public:
+  /////////////////////////////////////////////////////
+  // nsISupports methods
+  NS_DECL_ISUPPORTS
+
+  /////////////////////////////////////////////////////
+  // nsIStreamConverterService methods
+  NS_DECL_NSISTREAMCONVERTERSERVICE
+
+  /////////////////////////////////////////////////////
+  // nsStreamConverterService methods
+  nsStreamConverterService() = default;
+
+ private:
+  virtual ~nsStreamConverterService() = default;
+
+  // Responsible for finding a converter for the given MIME-type.
+  nsresult FindConverter(const char* aContractID,
+                         nsTArray<nsCString>** aEdgeList);
+  nsresult BuildGraph(void);
+  nsresult AddAdjacency(const char* aContractID);
+  nsresult ParseFromTo(const char* aContractID, nsCString& aFromRes,
+                       nsCString& aToRes);
+
+  // member variables
+  nsClassHashtable<nsCStringHashKey, nsTArray<RefPtr<nsAtom>>> mAdjacencyList;
+};
+
+#endif  // __nsstreamconverterservice__h___