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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=4 sw=2 sts=2 et cindent: */
/* 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/RangedPtr.h"
#include "mozilla/TextUtils.h"

#include <algorithm>
#include <iterator>

#include "nsASCIIMask.h"
#include "nsURLHelper.h"
#include "nsIFile.h"
#include "nsIURLParser.h"
#include "nsCOMPtr.h"
#include "nsCRT.h"
#include "nsNetCID.h"
#include "mozilla/Preferences.h"
#include "prnetdb.h"
#include "mozilla/Tokenizer.h"
#include "nsEscape.h"
#include "rust-helper/src/helper.h"

using namespace mozilla;

//----------------------------------------------------------------------------
// Init/Shutdown
//----------------------------------------------------------------------------

static bool gInitialized = false;
static nsIURLParser *gNoAuthURLParser = nullptr;
static nsIURLParser *gAuthURLParser = nullptr;
static nsIURLParser *gStdURLParser = nullptr;
static int32_t gMaxLength = 1048576;  // Default: 1MB

static void InitGlobals() {
  nsCOMPtr<nsIURLParser> parser;

  parser = do_GetService(NS_NOAUTHURLPARSER_CONTRACTID);
  NS_ASSERTION(parser, "failed getting 'noauth' url parser");
  if (parser) {
    gNoAuthURLParser = parser.get();
    NS_ADDREF(gNoAuthURLParser);
  }

  parser = do_GetService(NS_AUTHURLPARSER_CONTRACTID);
  NS_ASSERTION(parser, "failed getting 'auth' url parser");
  if (parser) {
    gAuthURLParser = parser.get();
    NS_ADDREF(gAuthURLParser);
  }

  parser = do_GetService(NS_STDURLPARSER_CONTRACTID);
  NS_ASSERTION(parser, "failed getting 'std' url parser");
  if (parser) {
    gStdURLParser = parser.get();
    NS_ADDREF(gStdURLParser);
  }

  gInitialized = true;
  Preferences::AddIntVarCache(&gMaxLength, "network.standard-url.max-length",
                              1048576);
}

void net_ShutdownURLHelper() {
  if (gInitialized) {
    NS_IF_RELEASE(gNoAuthURLParser);
    NS_IF_RELEASE(gAuthURLParser);
    NS_IF_RELEASE(gStdURLParser);
    gInitialized = false;
  }
}

int32_t net_GetURLMaxLength() { return gMaxLength; }

//----------------------------------------------------------------------------
// nsIURLParser getters
//----------------------------------------------------------------------------

nsIURLParser *net_GetAuthURLParser() {
  if (!gInitialized) InitGlobals();
  return gAuthURLParser;
}

nsIURLParser *net_GetNoAuthURLParser() {
  if (!gInitialized) InitGlobals();
  return gNoAuthURLParser;
}

nsIURLParser *net_GetStdURLParser() {
  if (!gInitialized) InitGlobals();
  return gStdURLParser;
}

//---------------------------------------------------------------------------
// GetFileFromURLSpec implementations
//---------------------------------------------------------------------------
nsresult net_GetURLSpecFromDir(nsIFile *aFile, nsACString &result) {
  nsAutoCString escPath;
  nsresult rv = net_GetURLSpecFromActualFile(aFile, escPath);
  if (NS_FAILED(rv)) return rv;

  if (escPath.Last() != '/') {
    escPath += '/';
  }

  result = escPath;
  return NS_OK;
}

nsresult net_GetURLSpecFromFile(nsIFile *aFile, nsACString &result) {
  nsAutoCString escPath;
  nsresult rv = net_GetURLSpecFromActualFile(aFile, escPath);
  if (NS_FAILED(rv)) return rv;

  // if this file references a directory, then we need to ensure that the
  // URL ends with a slash.  this is important since it affects the rules
  // for relative URL resolution when this URL is used as a base URL.
  // if the file does not exist, then we make no assumption about its type,
  // and simply leave the URL unmodified.
  if (escPath.Last() != '/') {
    bool dir;
    rv = aFile->IsDirectory(&dir);
    if (NS_SUCCEEDED(rv) && dir) escPath += '/';
  }

  result = escPath;
  return NS_OK;
}

//----------------------------------------------------------------------------
// file:// URL parsing
//----------------------------------------------------------------------------

nsresult net_ParseFileURL(const nsACString &inURL, nsACString &outDirectory,
                          nsACString &outFileBaseName,
                          nsACString &outFileExtension) {
  nsresult rv;

  if (inURL.Length() > (uint32_t)gMaxLength) {
    return NS_ERROR_MALFORMED_URI;
  }

  outDirectory.Truncate();
  outFileBaseName.Truncate();
  outFileExtension.Truncate();

  const nsPromiseFlatCString &flatURL = PromiseFlatCString(inURL);
  const char *url = flatURL.get();

  nsAutoCString scheme;
  rv = net_ExtractURLScheme(flatURL, scheme);
  if (NS_FAILED(rv)) return rv;

  if (!scheme.EqualsLiteral("file")) {
    NS_ERROR("must be a file:// url");
    return NS_ERROR_UNEXPECTED;
  }

  nsIURLParser *parser = net_GetNoAuthURLParser();
  NS_ENSURE_TRUE(parser, NS_ERROR_UNEXPECTED);

  uint32_t pathPos, filepathPos, directoryPos, basenamePos, extensionPos;
  int32_t pathLen, filepathLen, directoryLen, basenameLen, extensionLen;

  // invoke the parser to extract the URL path
  rv = parser->ParseURL(url, flatURL.Length(), nullptr,
                        nullptr,           // don't care about scheme
                        nullptr, nullptr,  // don't care about authority
                        &pathPos, &pathLen);
  if (NS_FAILED(rv)) return rv;

  // invoke the parser to extract filepath from the path
  rv = parser->ParsePath(url + pathPos, pathLen, &filepathPos, &filepathLen,
                         nullptr, nullptr,   // don't care about query
                         nullptr, nullptr);  // don't care about ref
  if (NS_FAILED(rv)) return rv;

  filepathPos += pathPos;

  // invoke the parser to extract the directory and filename from filepath
  rv = parser->ParseFilePath(url + filepathPos, filepathLen, &directoryPos,
                             &directoryLen, &basenamePos, &basenameLen,
                             &extensionPos, &extensionLen);
  if (NS_FAILED(rv)) return rv;

  if (directoryLen > 0)
    outDirectory = Substring(inURL, filepathPos + directoryPos, directoryLen);
  if (basenameLen > 0)
    outFileBaseName = Substring(inURL, filepathPos + basenamePos, basenameLen);
  if (extensionLen > 0)
    outFileExtension =
        Substring(inURL, filepathPos + extensionPos, extensionLen);
  // since we are using a no-auth url parser, there will never be a host
  // XXX not strictly true... file://localhost/foo/bar.html is a valid URL

  return NS_OK;
}

//----------------------------------------------------------------------------
// path manipulation functions
//----------------------------------------------------------------------------

// Replace all /./ with a / while resolving URLs
// But only till #?
void net_CoalesceDirs(netCoalesceFlags flags, char *path) {
  /* Stolen from the old netlib's mkparse.c.
   *
   * modifies a url of the form   /foo/../foo1  ->  /foo1
   *                       and    /foo/./foo1   ->  /foo/foo1
   *                       and    /foo/foo1/..  ->  /foo/
   */
  char *fwdPtr = path;
  char *urlPtr = path;
  char *lastslash = path;
  uint32_t traversal = 0;
  uint32_t special_ftp_len = 0;

  /* Remember if this url is a special ftp one: */
  if (flags & NET_COALESCE_DOUBLE_SLASH_IS_ROOT) {
    /* some schemes (for example ftp) have the speciality that
       the path can begin // or /%2F to mark the root of the
       servers filesystem, a simple / only marks the root relative
       to the user loging in. We remember the length of the marker */
    if (nsCRT::strncasecmp(path, "/%2F", 4) == 0)
      special_ftp_len = 4;
    else if (strncmp(path, "//", 2) == 0)
      special_ftp_len = 2;
  }

  /* find the last slash before # or ? */
  for (; (*fwdPtr != '\0') && (*fwdPtr != '?') && (*fwdPtr != '#'); ++fwdPtr) {
  }

  /* found nothing, but go back one only */
  /* if there is something to go back to */
  if (fwdPtr != path && *fwdPtr == '\0') {
    --fwdPtr;
  }

  /* search the slash */
  for (; (fwdPtr != path) && (*fwdPtr != '/'); --fwdPtr) {
  }
  lastslash = fwdPtr;
  fwdPtr = path;

  /* replace all %2E or %2e with . in the path */
  /* but stop at lastchar if non null */
  for (; (*fwdPtr != '\0') && (*fwdPtr != '?') && (*fwdPtr != '#') &&
         (*lastslash == '\0' || fwdPtr != lastslash);
       ++fwdPtr) {
    if (*fwdPtr == '%' && *(fwdPtr + 1) == '2' &&
        (*(fwdPtr + 2) == 'E' || *(fwdPtr + 2) == 'e')) {
      *urlPtr++ = '.';
      ++fwdPtr;
      ++fwdPtr;
    } else {
      *urlPtr++ = *fwdPtr;
    }
  }
  // Copy remaining stuff past the #?;
  for (; *fwdPtr != '\0'; ++fwdPtr) {
    *urlPtr++ = *fwdPtr;
  }
  *urlPtr = '\0';  // terminate the url

  // start again, this time for real
  fwdPtr = path;
  urlPtr = path;

  for (; (*fwdPtr != '\0') && (*fwdPtr != '?') && (*fwdPtr != '#'); ++fwdPtr) {
    if (*fwdPtr == '/' && *(fwdPtr + 1) == '.' && *(fwdPtr + 2) == '/') {
      // remove . followed by slash
      ++fwdPtr;
    } else if (*fwdPtr == '/' && *(fwdPtr + 1) == '.' && *(fwdPtr + 2) == '.' &&
               (*(fwdPtr + 3) == '/' ||
                *(fwdPtr + 3) == '\0' ||  // This will take care of
                *(fwdPtr + 3) == '?' ||   // something like foo/bar/..#sometag
                *(fwdPtr + 3) == '#')) {
      // remove foo/..
      // reverse the urlPtr to the previous slash if possible
      // if url does not allow relative root then drop .. above root
      // otherwise retain them in the path
      if (traversal > 0 || !(flags & NET_COALESCE_ALLOW_RELATIVE_ROOT)) {
        if (urlPtr != path) urlPtr--;  // we must be going back at least by one
        for (; *urlPtr != '/' && urlPtr != path; urlPtr--)
          ;           // null body
        --traversal;  // count back
        // forward the fwdPtr past the ../
        fwdPtr += 2;
        // if we have reached the beginning of the path
        // while searching for the previous / and we remember
        // that it is an url that begins with /%2F then
        // advance urlPtr again by 3 chars because /%2F already
        // marks the root of the path
        if (urlPtr == path && special_ftp_len > 3) {
          ++urlPtr;
          ++urlPtr;
          ++urlPtr;
        }
        // special case if we have reached the end
        // to preserve the last /
        if (*fwdPtr == '.' && *(fwdPtr + 1) == '\0') ++urlPtr;
      } else {
        // there are to much /.. in this path, just copy them instead.
        // forward the urlPtr past the /.. and copying it

        // However if we remember it is an url that starts with
        // /%2F and urlPtr just points at the "F" of "/%2F" then do
        // not overwrite it with the /, just copy .. and move forward
        // urlPtr.
        if (special_ftp_len > 3 && urlPtr == path + special_ftp_len - 1)
          ++urlPtr;
        else
          *urlPtr++ = *fwdPtr;
        ++fwdPtr;
        *urlPtr++ = *fwdPtr;
        ++fwdPtr;
        *urlPtr++ = *fwdPtr;
      }
    } else {
      // count the hierachie, but only if we do not have reached
      // the root of some special urls with a special root marker
      if (*fwdPtr == '/' && *(fwdPtr + 1) != '.' &&
          (special_ftp_len != 2 || *(fwdPtr + 1) != '/'))
        traversal++;
      // copy the url incrementaly
      *urlPtr++ = *fwdPtr;
    }
  }

  /*
   *  Now lets remove trailing . case
   *     /foo/foo1/.   ->  /foo/foo1/
   */

  if ((urlPtr > (path + 1)) && (*(urlPtr - 1) == '.') && (*(urlPtr - 2) == '/'))
    urlPtr--;

  // Copy remaining stuff past the #?;
  for (; *fwdPtr != '\0'; ++fwdPtr) {
    *urlPtr++ = *fwdPtr;
  }
  *urlPtr = '\0';  // terminate the url
}

nsresult net_ResolveRelativePath(const nsACString &relativePath,
                                 const nsACString &basePath,
                                 nsACString &result) {
  nsAutoCString name;
  nsAutoCString path(basePath);
  bool needsDelim = false;

  if (!path.IsEmpty()) {
    char16_t last = path.Last();
    needsDelim = !(last == '/');
  }

  nsACString::const_iterator beg, end;
  relativePath.BeginReading(beg);
  relativePath.EndReading(end);

  bool stop = false;
  char c;
  for (; !stop; ++beg) {
    c = (beg == end) ? '\0' : *beg;
    // printf("%c [name=%s] [path=%s]\n", c, name.get(), path.get());
    switch (c) {
      case '\0':
      case '#':
      case '?':
        stop = true;
        MOZ_FALLTHROUGH;
      case '/':
        // delimiter found
        if (name.EqualsLiteral("..")) {
          // pop path
          // If we already have the delim at end, then
          //  skip over that when searching for next one to the left
          int32_t offset = path.Length() - (needsDelim ? 1 : 2);
          // First check for errors
          if (offset < 0) return NS_ERROR_MALFORMED_URI;
          int32_t pos = path.RFind("/", false, offset);
          if (pos >= 0)
            path.Truncate(pos + 1);
          else
            path.Truncate();
        } else if (name.IsEmpty() || name.EqualsLiteral(".")) {
          // do nothing
        } else {
          // append name to path
          if (needsDelim) path += '/';
          path += name;
          needsDelim = true;
        }
        name.Truncate();
        break;

      default:
        // append char to name
        name += c;
    }
  }
  // append anything left on relativePath (e.g. #..., ;..., ?...)
  if (c != '\0') path += Substring(--beg, end);

  result = path;
  return NS_OK;
}

//----------------------------------------------------------------------------
// scheme fu
//----------------------------------------------------------------------------

static bool net_IsValidSchemeChar(const char aChar) {
  if (IsAsciiAlpha(aChar) || IsAsciiDigit(aChar) || aChar == '+' ||
      aChar == '.' || aChar == '-') {
    return true;
  }
  return false;
}

/* Extract URI-Scheme if possible */
nsresult net_ExtractURLScheme(const nsACString &inURI, nsACString &scheme) {
  nsACString::const_iterator start, end;
  inURI.BeginReading(start);
  inURI.EndReading(end);

  // Strip C0 and space from begining
  while (start != end) {
    if ((uint8_t)*start > 0x20) {
      break;
    }
    start++;
  }

  Tokenizer p(Substring(start, end), "\r\n\t");
  p.Record();
  if (!p.CheckChar(IsAsciiAlpha)) {
    // First char must be alpha
    return NS_ERROR_MALFORMED_URI;
  }

  while (p.CheckChar(net_IsValidSchemeChar) || p.CheckWhite()) {
    // Skip valid scheme characters or \r\n\t
  }

  if (!p.CheckChar(':')) {
    return NS_ERROR_MALFORMED_URI;
  }

  p.Claim(scheme);
  scheme.StripTaggedASCII(ASCIIMask::MaskCRLFTab());
  ToLowerCase(scheme);
  return NS_OK;
}

bool net_IsValidScheme(const char *scheme, uint32_t schemeLen) {
  // first char must be alpha
  if (!IsAsciiAlpha(*scheme)) return false;

  // nsCStrings may have embedded nulls -- reject those too
  for (; schemeLen; ++scheme, --schemeLen) {
    if (!(IsAsciiAlpha(*scheme) || IsAsciiDigit(*scheme) || *scheme == '+' ||
          *scheme == '.' || *scheme == '-'))
      return false;
  }

  return true;
}

bool net_IsAbsoluteURL(const nsACString &uri) {
  nsACString::const_iterator start, end;
  uri.BeginReading(start);
  uri.EndReading(end);

  // Strip C0 and space from begining
  while (start != end) {
    if ((uint8_t)*start > 0x20) {
      break;
    }
    start++;
  }

  Tokenizer p(Substring(start, end), "\r\n\t");

  // First char must be alpha
  if (!p.CheckChar(IsAsciiAlpha)) {
    return false;
  }

  while (p.CheckChar(net_IsValidSchemeChar) || p.CheckWhite()) {
    // Skip valid scheme characters or \r\n\t
  }
  if (!p.CheckChar(':')) {
    return false;
  }
  p.SkipWhites();

  if (!p.CheckChar('/')) {
    return false;
  }
  p.SkipWhites();

  if (p.CheckChar('/')) {
    // aSpec is really absolute. Ignore aBaseURI in this case
    return true;
  }
  return false;
}

void net_FilterURIString(const nsACString &input, nsACString &result) {
  result.Truncate();

  auto start = input.BeginReading();
  auto end = input.EndReading();

  // Trim off leading and trailing invalid chars.
  auto charFilter = [](char c) { return static_cast<uint8_t>(c) > 0x20; };
  auto newStart = std::find_if(start, end, charFilter);
  auto newEnd =
      std::find_if(std::reverse_iterator<decltype(end)>(end),
                   std::reverse_iterator<decltype(newStart)>(newStart),
                   charFilter)
          .base();

  // Check if chars need to be stripped.
  bool needsStrip = false;
  const ASCIIMaskArray &mask = ASCIIMask::MaskCRLFTab();
  for (auto itr = start; itr != end; ++itr) {
    if (ASCIIMask::IsMasked(mask, *itr)) {
      needsStrip = true;
      break;
    }
  }

  // Just use the passed in string rather than creating new copies if no
  // changes are necessary.
  if (newStart == start && newEnd == end && !needsStrip) {
    result = input;
    return;
  }

  result.Assign(Substring(newStart, newEnd));
  if (needsStrip) {
    result.StripTaggedASCII(mask);
  }
}

nsresult net_FilterAndEscapeURI(const nsACString &aInput, uint32_t aFlags,
                                nsACString &aResult) {
  aResult.Truncate();

  auto start = aInput.BeginReading();
  auto end = aInput.EndReading();

  // Trim off leading and trailing invalid chars.
  auto charFilter = [](char c) { return static_cast<uint8_t>(c) > 0x20; };
  auto newStart = std::find_if(start, end, charFilter);
  auto newEnd =
      std::find_if(std::reverse_iterator<decltype(end)>(end),
                   std::reverse_iterator<decltype(newStart)>(newStart),
                   charFilter)
          .base();

  const ASCIIMaskArray &mask = ASCIIMask::MaskCRLFTab();
  return NS_EscapeAndFilterURL(Substring(newStart, newEnd), aFlags, &mask,
                               aResult, fallible);
}

#if defined(XP_WIN)
bool net_NormalizeFileURL(const nsACString &aURL, nsCString &aResultBuf) {
  bool writing = false;

  nsACString::const_iterator beginIter, endIter;
  aURL.BeginReading(beginIter);
  aURL.EndReading(endIter);

  const char *s, *begin = beginIter.get();

  for (s = begin; s != endIter.get(); ++s) {
    if (*s == '\\') {
      writing = true;
      if (s > begin) aResultBuf.Append(begin, s - begin);
      aResultBuf += '/';
      begin = s + 1;
    }
  }
  if (writing && s > begin) aResultBuf.Append(begin, s - begin);

  return writing;
}
#endif

//----------------------------------------------------------------------------
// miscellaneous (i.e., stuff that should really be elsewhere)
//----------------------------------------------------------------------------

static inline void ToLower(char &c) {
  if ((unsigned)(c - 'A') <= (unsigned)('Z' - 'A')) c += 'a' - 'A';
}

void net_ToLowerCase(char *str, uint32_t length) {
  for (char *end = str + length; str < end; ++str) ToLower(*str);
}

void net_ToLowerCase(char *str) {
  for (; *str; ++str) ToLower(*str);
}

char *net_FindCharInSet(const char *iter, const char *stop, const char *set) {
  for (; iter != stop && *iter; ++iter) {
    for (const char *s = set; *s; ++s) {
      if (*iter == *s) return (char *)iter;
    }
  }
  return (char *)iter;
}

char *net_FindCharNotInSet(const char *iter, const char *stop,
                           const char *set) {
repeat:
  for (const char *s = set; *s; ++s) {
    if (*iter == *s) {
      if (++iter == stop) break;
      goto repeat;
    }
  }
  return (char *)iter;
}

char *net_RFindCharNotInSet(const char *stop, const char *iter,
                            const char *set) {
  --iter;
  --stop;

  if (iter == stop) return (char *)iter;

repeat:
  for (const char *s = set; *s; ++s) {
    if (*iter == *s) {
      if (--iter == stop) break;
      goto repeat;
    }
  }
  return (char *)iter;
}

#define HTTP_LWS " \t"

// Return the index of the closing quote of the string, if any
static uint32_t net_FindStringEnd(const nsCString &flatStr,
                                  uint32_t stringStart, char stringDelim) {
  NS_ASSERTION(stringStart < flatStr.Length() &&
                   flatStr.CharAt(stringStart) == stringDelim &&
                   (stringDelim == '"' || stringDelim == '\''),
               "Invalid stringStart");

  const char set[] = {stringDelim, '\\', '\0'};
  do {
    // stringStart points to either the start quote or the last
    // escaped char (the char following a '\\')

    // Write to searchStart here, so that when we get back to the
    // top of the loop right outside this one we search from the
    // right place.
    uint32_t stringEnd = flatStr.FindCharInSet(set, stringStart + 1);
    if (stringEnd == uint32_t(kNotFound)) return flatStr.Length();

    if (flatStr.CharAt(stringEnd) == '\\') {
      // Hit a backslash-escaped char.  Need to skip over it.
      stringStart = stringEnd + 1;
      if (stringStart == flatStr.Length()) return stringStart;

      // Go back to looking for the next escape or the string end
      continue;
    }

    return stringEnd;

  } while (true);

  MOZ_ASSERT_UNREACHABLE("How did we get here?");
  return flatStr.Length();
}

static uint32_t net_FindMediaDelimiter(const nsCString &flatStr,
                                       uint32_t searchStart, char delimiter) {
  do {
    // searchStart points to the spot from which we should start looking
    // for the delimiter.
    const char delimStr[] = {delimiter, '"', '\0'};
    uint32_t curDelimPos = flatStr.FindCharInSet(delimStr, searchStart);
    if (curDelimPos == uint32_t(kNotFound)) return flatStr.Length();

    char ch = flatStr.CharAt(curDelimPos);
    if (ch == delimiter) {
      // Found delimiter
      return curDelimPos;
    }

    // We hit the start of a quoted string.  Look for its end.
    searchStart = net_FindStringEnd(flatStr, curDelimPos, ch);
    if (searchStart == flatStr.Length()) return searchStart;

    ++searchStart;

    // searchStart now points to the first char after the end of the
    // string, so just go back to the top of the loop and look for
    // |delimiter| again.
  } while (true);

  MOZ_ASSERT_UNREACHABLE("How did we get here?");
  return flatStr.Length();
}

// aOffset should be added to aCharsetStart and aCharsetEnd if this
// function sets them.
static void net_ParseMediaType(const nsACString &aMediaTypeStr,
                               nsACString &aContentType,
                               nsACString &aContentCharset, int32_t aOffset,
                               bool *aHadCharset, int32_t *aCharsetStart,
                               int32_t *aCharsetEnd, bool aStrict) {
  const nsCString &flatStr = PromiseFlatCString(aMediaTypeStr);
  const char *start = flatStr.get();
  const char *end = start + flatStr.Length();

  // Trim LWS leading and trailing whitespace from type.  We include '(' in
  // the trailing trim set to catch media-type comments, which are not at all
  // standard, but may occur in rare cases.
  const char *type = net_FindCharNotInSet(start, end, HTTP_LWS);
  const char *typeEnd = net_FindCharInSet(type, end, HTTP_LWS ";(");

  const char *charset = "";
  const char *charsetEnd = charset;
  int32_t charsetParamStart = 0;
  int32_t charsetParamEnd = 0;

  uint32_t consumed = typeEnd - type;

  // Iterate over parameters
  bool typeHasCharset = false;
  uint32_t paramStart = flatStr.FindChar(';', typeEnd - start);
  if (paramStart != uint32_t(kNotFound)) {
    // We have parameters.  Iterate over them.
    uint32_t curParamStart = paramStart + 1;
    do {
      uint32_t curParamEnd =
          net_FindMediaDelimiter(flatStr, curParamStart, ';');

      const char *paramName = net_FindCharNotInSet(
          start + curParamStart, start + curParamEnd, HTTP_LWS);
      static const char charsetStr[] = "charset=";
      if (PL_strncasecmp(paramName, charsetStr, sizeof(charsetStr) - 1) == 0) {
        charset = paramName + sizeof(charsetStr) - 1;
        charsetEnd = start + curParamEnd;
        typeHasCharset = true;
        charsetParamStart = curParamStart - 1;
        charsetParamEnd = curParamEnd;
      }

      consumed = curParamEnd;
      curParamStart = curParamEnd + 1;
    } while (curParamStart < flatStr.Length());
  }

  bool charsetNeedsQuotedStringUnescaping = false;
  if (typeHasCharset) {
    // Trim LWS leading and trailing whitespace from charset.  We include
    // '(' in the trailing trim set to catch media-type comments, which are
    // not at all standard, but may occur in rare cases.
    charset = net_FindCharNotInSet(charset, charsetEnd, HTTP_LWS);
    if (*charset == '"') {
      charsetNeedsQuotedStringUnescaping = true;
      charsetEnd =
          start + net_FindStringEnd(flatStr, charset - start, *charset);
      charset++;
      NS_ASSERTION(charsetEnd >= charset, "Bad charset parsing");
    } else {
      charsetEnd = net_FindCharInSet(charset, charsetEnd, HTTP_LWS ";(");
    }
  }

  // if the server sent "*/*", it is meaningless, so do not store it.
  // also, if type is the same as aContentType, then just update the
  // charset.  however, if charset is empty and aContentType hasn't
  // changed, then don't wipe-out an existing aContentCharset.  We
  // also want to reject a mime-type if it does not include a slash.
  // some servers give junk after the charset parameter, which may
  // include a comma, so this check makes us a bit more tolerant.

  if (type != typeEnd && memchr(type, '/', typeEnd - type) != nullptr &&
      (aStrict ? (net_FindCharNotInSet(start + consumed, end, HTTP_LWS) == end)
               : (strncmp(type, "*/*", typeEnd - type) != 0))) {
    // Common case here is that aContentType is empty
    bool eq = !aContentType.IsEmpty() &&
              aContentType.Equals(Substring(type, typeEnd),
                                  nsCaseInsensitiveCStringComparator());
    if (!eq) {
      aContentType.Assign(type, typeEnd - type);
      ToLowerCase(aContentType);
    }

    if ((!eq && *aHadCharset) || typeHasCharset) {
      *aHadCharset = true;
      if (charsetNeedsQuotedStringUnescaping) {
        // parameters using the "quoted-string" syntax need
        // backslash-escapes to be unescaped (see RFC 2616 Section 2.2)
        aContentCharset.Truncate();
        for (const char *c = charset; c != charsetEnd; c++) {
          if (*c == '\\' && c + 1 != charsetEnd) {
            // eat escape
            c++;
          }
          aContentCharset.Append(*c);
        }
      } else {
        aContentCharset.Assign(charset, charsetEnd - charset);
      }
      if (typeHasCharset) {
        *aCharsetStart = charsetParamStart + aOffset;
        *aCharsetEnd = charsetParamEnd + aOffset;
      }
    }
    // Only set a new charset position if this is a different type
    // from the last one we had and it doesn't already have a
    // charset param.  If this is the same type, we probably want
    // to leave the charset position on its first occurrence.
    if (!eq && !typeHasCharset) {
      int32_t charsetStart = int32_t(paramStart);
      if (charsetStart == kNotFound) charsetStart = flatStr.Length();

      *aCharsetEnd = *aCharsetStart = charsetStart + aOffset;
    }
  }
}

#undef HTTP_LWS

void net_ParseContentType(const nsACString &aHeaderStr,
                          nsACString &aContentType, nsACString &aContentCharset,
                          bool *aHadCharset) {
  int32_t dummy1, dummy2;
  net_ParseContentType(aHeaderStr, aContentType, aContentCharset, aHadCharset,
                       &dummy1, &dummy2);
}

void net_ParseContentType(const nsACString &aHeaderStr,
                          nsACString &aContentType, nsACString &aContentCharset,
                          bool *aHadCharset, int32_t *aCharsetStart,
                          int32_t *aCharsetEnd) {
  //
  // Augmented BNF (from RFC 2616 section 3.7):
  //
  //   header-value = media-type *( LWS "," LWS media-type )
  //   media-type   = type "/" subtype *( LWS ";" LWS parameter )
  //   type         = token
  //   subtype      = token
  //   parameter    = attribute "=" value
  //   attribute    = token
  //   value        = token | quoted-string
  //
  //
  // Examples:
  //
  //   text/html
  //   text/html, text/html
  //   text/html,text/html; charset=ISO-8859-1
  //   text/html,text/html; charset="ISO-8859-1"
  //   text/html;charset=ISO-8859-1, text/html
  //   text/html;charset='ISO-8859-1', text/html
  //   application/octet-stream
  //

  *aHadCharset = false;
  const nsCString &flatStr = PromiseFlatCString(aHeaderStr);

  // iterate over media-types.  Note that ',' characters can happen
  // inside quoted strings, so we need to watch out for that.
  uint32_t curTypeStart = 0;
  do {
    // curTypeStart points to the start of the current media-type.  We want
    // to look for its end.
    uint32_t curTypeEnd = net_FindMediaDelimiter(flatStr, curTypeStart, ',');

    // At this point curTypeEnd points to the spot where the media-type
    // starting at curTypeEnd ends.  Time to parse that!
    net_ParseMediaType(
        Substring(flatStr, curTypeStart, curTypeEnd - curTypeStart),
        aContentType, aContentCharset, curTypeStart, aHadCharset, aCharsetStart,
        aCharsetEnd, false);

    // And let's move on to the next media-type
    curTypeStart = curTypeEnd + 1;
  } while (curTypeStart < flatStr.Length());
}

void net_ParseRequestContentType(const nsACString &aHeaderStr,
                                 nsACString &aContentType,
                                 nsACString &aContentCharset,
                                 bool *aHadCharset) {
  //
  // Augmented BNF (from RFC 7231 section 3.1.1.1):
  //
  //   media-type   = type "/" subtype *( OWS ";" OWS parameter )
  //   type         = token
  //   subtype      = token
  //   parameter    = token "=" ( token / quoted-string )
  //
  // Examples:
  //
  //   text/html
  //   text/html; charset=ISO-8859-1
  //   text/html; charset="ISO-8859-1"
  //   application/octet-stream
  //

  aContentType.Truncate();
  aContentCharset.Truncate();
  *aHadCharset = false;
  const nsCString &flatStr = PromiseFlatCString(aHeaderStr);

  // At this point curTypeEnd points to the spot where the media-type
  // starting at curTypeEnd ends.  Time to parse that!
  nsAutoCString contentType, contentCharset;
  bool hadCharset = false;
  int32_t dummy1, dummy2;
  uint32_t typeEnd = net_FindMediaDelimiter(flatStr, 0, ',');
  if (typeEnd != flatStr.Length()) {
    // We have some stuff left at the end, so this is not a valid
    // request Content-Type header.
    return;
  }
  net_ParseMediaType(flatStr, contentType, contentCharset, 0, &hadCharset,
                     &dummy1, &dummy2, true);

  aContentType = contentType;
  aContentCharset = contentCharset;
  *aHadCharset = hadCharset;
}

bool net_IsValidHostName(const nsACString &host) {
  const char *end = host.EndReading();
  // Use explicit whitelists to select which characters we are
  // willing to send to lower-level DNS logic. This is more
  // self-documenting, and can also be slightly faster than the
  // blacklist approach, since DNS names are the common case, and
  // the commonest characters will tend to be near the start of
  // the list.

  // Whitelist for DNS names (RFC 1035) with extra characters added
  // for pragmatic reasons "$+_"
  // see https://bugzilla.mozilla.org/show_bug.cgi?id=355181#c2
  if (net_FindCharNotInSet(host.BeginReading(), end,
                           "abcdefghijklmnopqrstuvwxyz"
                           ".-0123456789"
                           "ABCDEFGHIJKLMNOPQRSTUVWXYZ$+_") == end)
    return true;

  // Might be a valid IPv6 link-local address containing a percent sign
  nsAutoCString strhost(host);
  PRNetAddr addr;
  return PR_StringToNetAddr(strhost.get(), &addr) == PR_SUCCESS;
}

bool net_IsValidIPv4Addr(const nsACString &aAddr) {
  return rust_net_is_valid_ipv4_addr(aAddr);
}

bool net_IsValidIPv6Addr(const char *addr, int32_t addrLen) {
  RangedPtr<const char> p(addr, addrLen);

  int32_t digits = 0;      // number of digits in current block
  int32_t colons = 0;      // number of colons in a row during parsing
  int32_t blocks = 0;      // number of hexadecimal blocks
  bool haveZeros = false;  // true if double colon is present in the address

  for (; addrLen; ++p, --addrLen) {
    if (*p == ':') {
      if (colons == 0) {
        if (digits != 0) {
          digits = 0;
          blocks++;
        }
      } else if (colons == 1) {
        if (haveZeros) return false;  // only one occurrence is allowed
        haveZeros = true;
      } else {
        // too many colons in a row
        return false;
      }
      colons++;
    } else if ((*p >= '0' && *p <= '9') || (*p >= 'a' && *p <= 'f') ||
               (*p >= 'A' && *p <= 'F')) {
      if (colons == 1 && blocks == 0)  // starts with a single colon
        return false;
      if (digits == 4)  // too many digits
        return false;
      colons = 0;
      digits++;
    } else if (*p == '.') {
      // check valid IPv4 from the beginning of the last block
      if (!net_IsValidIPv4Addr(
              Substring(p.get() - digits, p.get() + addrLen))) {
        return false;
      }
      return (haveZeros && blocks < 6) || (!haveZeros && blocks == 6);
    } else {
      // invalid character
      return false;
    }
  }

  if (colons == 1)  // ends with a single colon
    return false;

  if (digits)  // there is a block at the end
    blocks++;

  return (haveZeros && blocks < 8) || (!haveZeros && blocks == 8);
}