C++ nsACString::Truncate方法代码示例

void
nsCertOverride::convertBitsToString(OverrideBits ob, nsACString &str)
{
  str.Truncate();

  if (ob & ob_Mismatch)
    str.Append('M');

  if (ob & ob_Untrusted)
    str.Append('U');

  if (ob & ob_Time_error)
    str.Append('T');
}

NS_IMETHODIMP
nsNNTPNewsgroupList::InitXHDR(nsACString &header)
{
  if (++m_currentXHDRIndex >= m_filterHeaders.Length())
    header.Truncate();
  else
    header.Assign(m_filterHeaders[m_currentXHDRIndex]);
  // Don't include these in our XHDR bouts, as they are already provided through
  // XOVER. 
  if (header.EqualsLiteral("message-id") ||
      header.EqualsLiteral("references"))
    return InitXHDR(header);
  return NS_OK;
}

NS_IMETHODIMP
HttpBaseChannel::nsContentEncodings::GetNext(nsACString& aNextEncoding)
{
  aNextEncoding.Truncate();
  if (!mReady) {
    nsresult rv = PrepareForNext();
    if (NS_FAILED(rv)) {
      return NS_ERROR_FAILURE;
    }
  }

  const nsACString & encoding = Substring(mCurStart, mCurEnd);

  nsACString::const_iterator start, end;
  encoding.BeginReading(start);
  encoding.EndReading(end);

  bool haveType = false;
  if (CaseInsensitiveFindInReadable(NS_LITERAL_CSTRING("gzip"), start, end)) {
    aNextEncoding.AssignLiteral(APPLICATION_GZIP);
    haveType = true;
  }

  if (!haveType) {
    encoding.BeginReading(start);
    if (CaseInsensitiveFindInReadable(NS_LITERAL_CSTRING("compress"), start, end)) {
      aNextEncoding.AssignLiteral(APPLICATION_COMPRESS);
      haveType = true;
    }
  }
    
  if (!haveType) {
    encoding.BeginReading(start);
    if (CaseInsensitiveFindInReadable(NS_LITERAL_CSTRING("deflate"), start, end)) {
      aNextEncoding.AssignLiteral(APPLICATION_ZIP);
      haveType = true;
    }
  }

  // Prepare to fetch the next encoding
  mCurEnd = mCurStart;
  mReady = false;
  
  if (haveType)
    return NS_OK;

  NS_WARNING("Unknown encoding type");
  return NS_ERROR_FAILURE;
}

nsresult _OldStorage::AssembleCacheKey(nsIURI *aURI,
                                       nsACString const & aIdExtension,
                                       nsACString & aCacheKey,
                                       nsACString & aScheme)
{
  // Copied from nsHttpChannel::AssembleCacheKey

  aCacheKey.Truncate();

  nsresult rv;

  rv = aURI->GetScheme(aScheme);
  NS_ENSURE_SUCCESS(rv, rv);

  nsAutoCString uriSpec;
  if (aScheme.EqualsLiteral("http") ||
      aScheme.EqualsLiteral("https")) {
    if (mLoadInfo->IsAnonymous()) {
      aCacheKey.AssignLiteral("anon&");
    }

    if (!aIdExtension.IsEmpty()) {
      aCacheKey.AppendPrintf("id=%s&", aIdExtension.BeginReading());
    }

    nsCOMPtr<nsIURI> noRefURI;
    rv = aURI->CloneIgnoringRef(getter_AddRefs(noRefURI));
    NS_ENSURE_SUCCESS(rv, rv);

    rv = noRefURI->GetAsciiSpec(uriSpec);
    NS_ENSURE_SUCCESS(rv, rv);

    if (!aCacheKey.IsEmpty()) {
      aCacheKey.AppendLiteral("uri=");
    }
  }
  else if (aScheme.EqualsLiteral("wyciwyg")) {
    rv = aURI->GetSpec(uriSpec);
    NS_ENSURE_SUCCESS(rv, rv);
  }
  else {
    rv = aURI->GetAsciiSpec(uriSpec);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  aCacheKey.Append(uriSpec);

  return NS_OK;
}

/* ACString ConvertUTF8toACE (in AUTF8String input); */
NS_IMETHODIMP nsIDNService::ConvertUTF8toACE(const nsACString & input, nsACString & ace)
{
  // protect against bogus input
  NS_ENSURE_TRUE(IsUTF8(input), NS_ERROR_UNEXPECTED);

  nsresult rv;
  NS_ConvertUTF8toUCS2 ustr(input);

  // map ideographic period to ASCII period etc.
  normalizeFullStops(ustr);


  PRUint32 len, offset;
  len = 0;
  offset = 0;
  nsCAutoString encodedBuf;

  nsAString::const_iterator start, end;
  ustr.BeginReading(start); 
  ustr.EndReading(end); 
  ace.Truncate();

  // encode nodes if non ASCII
  while (start != end) {
    len++;
    if (*start++ == (PRUnichar)'.') {
      rv = stringPrepAndACE(Substring(ustr, offset, len - 1), encodedBuf);
      NS_ENSURE_SUCCESS(rv, rv);

      ace.Append(encodedBuf);
      ace.Append('.');
      offset += len;
      len = 0;
    }
  }

  // add extra node for multilingual test bed
  if (mMultilingualTestBed)
    ace.AppendLiteral("mltbd.");
  // encode the last node if non ASCII
  if (len) {
    rv = stringPrepAndACE(Substring(ustr, offset, len), encodedBuf);
    NS_ENSURE_SUCCESS(rv, rv);

    ace.Append(encodedBuf);
  }

  return NS_OK;
}

/**
 * Given a string which contains a list of Header addresses, returns a
 * comma-separated list of just the `mailbox' portions.
 */
NS_IMETHODIMP
nsMsgHeaderParser::ExtractHeaderAddressMailboxes(const nsACString &aLine,
        nsACString &aResult)
{
    if (aLine.IsEmpty())
    {
        aResult.Truncate();
        return NS_OK;
    }

    char *addrs = 0;
    int status = msg_parse_Header_addresses(PromiseFlatCString(aLine).get(),
                                            NULL, &addrs);
    if (status <= 0)
        return NS_ERROR_OUT_OF_MEMORY;

    char *s = addrs;
    PRUint32 i, size = 0;

    for (i = 0; (int) i < status; i++)
    {
        PRUint32 j = strlen(s);
        s += j + 1;
        size += j;
        if ((int)(i + 1) < status)
            size += 2;
    }

    nsCString result;
    result.SetLength(size);
    s = addrs;
    char* out = result.BeginWriting();
    for (i = 0; (int)i < status; i++)
    {
        PRUint32 j = strlen(s);
        memcpy(out, s, j);
        out += j;
        if ((int)(i+1) < status)
        {
            *out++ = ',';
            *out++ = ' ';
        }
        s += j + 1;
    }

    PR_Free(addrs);
    aResult = result;
    return NS_OK;
}

nsresult nsIDNService::ACEtoUTF8(const nsACString & input, nsACString & _retval,
                                 stringPrepFlag flag)
{
  // RFC 3490 - 4.2 ToUnicode
  // ToUnicode never fails.  If any step fails, then the original input
  // sequence is returned immediately in that step.
  //
  // Note that this refers to the decoding of a single label.
  // ACEtoUTF8 may be called with a sequence of labels separated by dots;
  // this test applies individually to each label.

  uint32_t len = 0, offset = 0;
  nsAutoCString decodedBuf;

  nsACString::const_iterator start, end;
  input.BeginReading(start);
  input.EndReading(end);
  _retval.Truncate();

  // loop and decode nodes
  while (start != end) {
    len++;
    if (*start++ == '.') {
      nsDependentCSubstring origLabel(input, offset, len - 1);
      if (NS_FAILED(decodeACE(origLabel, decodedBuf, flag))) {
        // If decoding failed, use the original input sequence
        // for this label.
        _retval.Append(origLabel);
      } else {
        _retval.Append(decodedBuf);
      }

      _retval.Append('.');
      offset += len;
      len = 0;
    }
  }
  // decode the last node
  if (len) {
    nsDependentCSubstring origLabel(input, offset, len);
    if (NS_FAILED(decodeACE(origLabel, decodedBuf, flag))) {
      _retval.Append(origLabel);
    } else {
      _retval.Append(decodedBuf);
    }
  }

  return NS_OK;
}

NS_IMETHODIMP
RustURL::GetSpecIgnoringRef(nsACString & aSpecIgnoringRef)
{
  nsresult rv = GetSpec(aSpecIgnoringRef);
  if (NS_FAILED(rv)) {
    return rv;
  }
  int32_t pos = aSpecIgnoringRef.FindChar('#');
  if (pos == kNotFound) {
    return NS_OK;
  }

  aSpecIgnoringRef.Truncate(pos);
  return NS_OK;
}

NS_IMETHODIMP nsAbCardProperty::GetUuid(nsACString &uuid)
{
  // If we have indeterminate sub-ids, return an empty uuid.
  if (m_directoryId.Equals("") || m_localId.Equals(""))
  {
    uuid.Truncate();
    return NS_OK;
  }

  nsresult rv;
  nsCOMPtr<nsIAbManager> manager = do_GetService(NS_ABMANAGER_CONTRACTID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  return manager->GenerateUUID(m_directoryId, m_localId, uuid);
}

/**
 Computes in the location specified by base64Out the SHA256 digest
 of the DER Encoded subject Public Key Info for the given cert
*/
static nsresult
GetBase64HashSPKI(const CERTCertificate* cert, nsACString& hashSPKIDigest)
{
  hashSPKIDigest.Truncate();
  Digest digest;
  nsresult rv = digest.DigestBuf(SEC_OID_SHA256, cert->derPublicKey.data,
                                 cert->derPublicKey.len);
  if (NS_FAILED(rv)) {
    return rv;
  }
  return Base64Encode(nsDependentCSubstring(
                        reinterpret_cast<const char*>(digest.get().data),
                        digest.get().len),
                      hashSPKIDigest);
}

nsresult
nsUnixSystemProxySettings::GetPACURI(nsACString& aResult)
{
  if (mProxySettings) {
    nsCString proxyMode;
    // Check if mode is auto
    nsresult rv = mProxySettings->GetString(NS_LITERAL_CSTRING("mode"), proxyMode);
    if (rv == NS_OK && proxyMode.EqualsLiteral("auto")) {
      return mProxySettings->GetString(NS_LITERAL_CSTRING("autoconfig-url"), aResult);
    }
    /* The org.gnome.system.proxy schema has been found, but auto mode is not set.
     * Don't try the GConf and return empty string. */
    aResult.Truncate();
    return NS_OK;
  }

  if (mGConf && IsProxyMode("auto")) {
    return mGConf->GetString(NS_LITERAL_CSTRING("/system/proxy/autoconfig_url"),
                             aResult);
  }
  // Return an empty string when auto mode is not set.
  aResult.Truncate();
  return NS_OK;
}

/* static */
nsresult DocGroup::GetKey(nsIPrincipal* aPrincipal, nsACString& aKey) {
  // Use GetBaseDomain() to handle things like file URIs, IP address URIs,
  // etc. correctly.
  nsresult rv = aPrincipal->GetBaseDomain(aKey);
  if (NS_FAILED(rv)) {
    // We don't really know what to do here.  But we should be conservative,
    // otherwise it would be possible to reorder two events incorrectly in the
    // future if we interrupt at the DocGroup level, so to be safe, use an
    // empty string to classify all such documents as belonging to the same
    // DocGroup.
    aKey.Truncate();
  }

  return rv;
}

nsresult nsIDNService::stringPrepAndACE(const nsAString& in, nsACString& out,
                                        stringPrepFlag flag)
{
  nsresult rv = NS_OK;

  out.Truncate();

  if (in.Length() > kMaxDNSNodeLen) {
    NS_WARNING("IDN node too large");
    return NS_ERROR_FAILURE;
  }

  if (IsASCII(in)) {
    LossyCopyUTF16toASCII(in, out);
    return NS_OK;
  }

  nsAutoString strPrep;
  rv = stringPrep(in, strPrep, flag);
  if (flag == eStringPrepForDNS) {
    NS_ENSURE_SUCCESS(rv, rv);
  }

  if (IsASCII(strPrep)) {
    LossyCopyUTF16toASCII(strPrep, out);
    return NS_OK;
  }

  if (flag == eStringPrepForUI && NS_SUCCEEDED(rv) && isLabelSafe(in)) {
    CopyUTF16toUTF8(strPrep, out);
    return NS_OK;
  }

  rv = punycode(strPrep, out);
  // Check that the encoded output isn't larger than the maximum length
  // of a DNS node per RFC 1034.
  // This test isn't necessary in the code paths above where the input
  // is ASCII (since the output will be the same length as the input) or
  // where we convert to UTF-8 (since the output is only used for
  // display in the UI and not passed to DNS and can legitimately be
  // longer than the limit).
  if (out.Length() > kMaxDNSNodeLen) {
    NS_WARNING("IDN node too large");
    return NS_ERROR_FAILURE;
  }

  return rv;
}

void
ICUUtils::LanguageTagIterForContent::GetNext(nsACString& aBCP47LangTag)
{
  if (mCurrentFallbackIndex < 0) {
    mCurrentFallbackIndex = 0;
    // Try the language specified by a 'lang'/'xml:lang' attribute on mContent
    // or any ancestor, if such an attribute is specified:
    nsAutoString lang;
    mContent->GetLang(lang);
    if (!lang.IsEmpty()) {
      aBCP47LangTag = NS_ConvertUTF16toUTF8(lang);
      return;
    }
  }

  if (mCurrentFallbackIndex < 1) {
    mCurrentFallbackIndex = 1;
    // Else try the language specified by any Content-Language HTTP header or
    // pragma directive:
    nsIDocument* doc = mContent->OwnerDoc();
    nsAutoString lang;
    doc->GetContentLanguage(lang);
    if (!lang.IsEmpty()) {
      aBCP47LangTag = NS_ConvertUTF16toUTF8(lang);
      return;
    }
  }

  if (mCurrentFallbackIndex < 2) {
    mCurrentFallbackIndex = 2;
    // Else try the user-agent's locale:
    nsCOMPtr<nsIToolkitChromeRegistry> cr =
      mozilla::services::GetToolkitChromeRegistryService();
    nsAutoCString uaLangTag;
    if (cr) {
      cr->GetSelectedLocale(NS_LITERAL_CSTRING("global"), uaLangTag);
    }
    if (!uaLangTag.IsEmpty()) {
      aBCP47LangTag = uaLangTag;
      return;
    }
  }

  // TODO: Probably not worth it, but maybe have a fourth fallback to using
  // the OS locale?

  aBCP47LangTag.Truncate(); // Signal iterator exhausted
}

nsresult nsIDNService::UTF8toACE(const nsACString & input, nsACString & ace, bool allowUnassigned, bool convertAllLabels)
{
  nsresult rv;
  NS_ConvertUTF8toUTF16 ustr(input);

  // map ideographic period to ASCII period etc.
  normalizeFullStops(ustr);


  uint32_t len, offset;
  len = 0;
  offset = 0;
  nsAutoCString encodedBuf;

  nsAString::const_iterator start, end;
  ustr.BeginReading(start); 
  ustr.EndReading(end); 
  ace.Truncate();

  // encode nodes if non ASCII
  while (start != end) {
    len++;
    if (*start++ == (char16_t)'.') {
      rv = stringPrepAndACE(Substring(ustr, offset, len - 1), encodedBuf,
                            allowUnassigned, convertAllLabels);
      NS_ENSURE_SUCCESS(rv, rv);

      ace.Append(encodedBuf);
      ace.Append('.');
      offset += len;
      len = 0;
    }
  }

  // add extra node for multilingual test bed
  if (mMultilingualTestBed)
    ace.AppendLiteral("mltbd.");
  // encode the last node if non ASCII
  if (len) {
    rv = stringPrepAndACE(Substring(ustr, offset, len), encodedBuf,
                          allowUnassigned, convertAllLabels);
    NS_ENSURE_SUCCESS(rv, rv);

    ace.Append(encodedBuf);
  }

  return NS_OK;
}