/** Logs a request using the current format. */
  public void log(HttpServletRequest req, HttpServletResponse res, ServletContext application)
      throws IOException {
    // server/1kk7
    CauchoRequest cRequest = (CauchoRequest) req;
    HttpServletResponseImpl responseImpl = (HttpServletResponseImpl) res;

    AbstractHttpRequest absRequest = cRequest.getAbstractHttpRequest();
    HttpServletRequestImpl request = absRequest.getRequestFacade();
    AbstractHttpResponse response = responseImpl.getAbstractHttpResponse();

    // skip excluded urls
    if (_excludes.length > 0) {
      byte[] data = absRequest.getUriBuffer();
      int sublen = absRequest.getUriLength();

      String uri = new String(data, 0, sublen);

      for (Pattern pattern : _excludes) {
        if (pattern.matcher(uri).find()) {
          return;
        }
      }
    }

    LogBuffer logBuffer = _logWriter.allocateBuffer();

    try {
      byte[] buffer = logBuffer.getBuffer();

      int length = log(request, responseImpl, response, buffer, 0, buffer.length);

      logBuffer.setLength(length);

      _logWriter.writeBuffer(logBuffer);
      logBuffer = null;
    } finally {
      if (logBuffer != null) _logWriter.freeBuffer(logBuffer);
    }
  }
  /**
   * Logs a request using the current format.
   *
   * @param request the servlet request.
   * @param response the servlet response.
   * @param buffer byte buffer containing the response
   * @param offset buffer starting offset
   * @param length length allowed in the buffer
   * @return the new tail of the buffer
   */
  private int log(
      HttpServletRequestImpl request,
      HttpServletResponseImpl responseFacade,
      AbstractHttpResponse response,
      byte[] buffer,
      int offset,
      int length)
      throws IOException {
    AbstractHttpRequest absRequest = request.getAbstractHttpRequest();

    int len = _segments.length;
    for (int i = 0; i < len; i++) {
      Segment segment = _segments[i];
      String value = null;
      CharSegment csValue = null;

      switch (segment._code) {
        case Segment.TEXT:
          int sublen = segment._data.length;
          byte[] data = segment._data;
          for (int j = 0; j < sublen; j++) buffer[offset++] = data[j];
          break;

        case Segment.CHAR:
          buffer[offset++] = segment._ch;
          break;

        case 'b':
          if (responseFacade.getStatus() == 304) buffer[offset++] = (byte) '-';
          else offset = print(buffer, offset, response.getContentLength());
          break;

          // cookie
        case 'c':
          Cookie cookie = request.getCookie(segment._string);
          if (cookie == null) cookie = responseFacade.getCookie(segment._string);
          if (cookie == null) buffer[offset++] = (byte) '-';
          else offset = print(buffer, offset, cookie.getValue());
          break;

          // set cookie
        case Segment.SET_COOKIE:
          ArrayList<Cookie> cookies = responseFacade.getCookies();
          if (cookies == null || cookies.size() == 0) buffer[offset++] = (byte) '-';
          else {
            _cb.clear();
            response.fillCookie(_cb, (Cookie) cookies.get(0), 0, 0, false);

            offset = print(buffer, offset, _cb.getBuffer(), 0, _cb.getLength());
          }
          break;

        case 'h':
          if (isHostnameDnsLookup()) {
            String addrName = request.getRemoteAddr();
            InetAddress addr = InetAddress.getByName(addrName);

            offset = print(buffer, offset, addr.getHostName());
          } else offset = absRequest.printRemoteAddr(buffer, offset);
          break;

          // input header
        case 'i':
          csValue = absRequest.getHeaderBuffer(segment._string);
          if (csValue == null) buffer[offset++] = (byte) '-';
          else offset = print(buffer, offset, csValue);
          break;

        case 'l':
          buffer[offset++] = (byte) '-';
          break;

          // request attribute
        case 'n':
          Object oValue = request.getAttribute(segment._string);
          if (oValue == null) buffer[offset++] = (byte) '-';
          else offset = print(buffer, offset, String.valueOf(oValue));
          break;

          // output header
        case 'o':
          value = response.getHeader(segment._string);
          if (value == null) buffer[offset++] = (byte) '-';
          else offset = print(buffer, offset, value);
          break;

        case 'r':
          offset = print(buffer, offset, request.getMethod());

          buffer[offset++] = (byte) ' ';

          data = absRequest.getUriBuffer();
          sublen = absRequest.getUriLength();

          // server/02e9
          if (buffer.length - offset - 128 < sublen) {
            sublen = buffer.length - offset - 128;
            System.arraycopy(data, 0, buffer, offset, sublen);
            offset += sublen;
            buffer[offset++] = (byte) '.';
            buffer[offset++] = (byte) '.';
            buffer[offset++] = (byte) '.';
          } else {
            System.arraycopy(data, 0, buffer, offset, sublen);
            offset += sublen;
          }

          buffer[offset++] = (byte) ' ';

          offset = print(buffer, offset, request.getProtocol());
          break;

        case 's':
          int status = responseFacade.getStatus();
          buffer[offset++] = (byte) ('0' + (status / 100) % 10);
          buffer[offset++] = (byte) ('0' + (status / 10) % 10);
          buffer[offset++] = (byte) ('0' + status % 10);
          break;

        case 't':
          long date = Alarm.getCurrentTime();

          if (date / 1000 != _lastTime / 1000) fillTime(date);

          sublen = _timeBuffer.getLength();
          data = _timeBuffer.getBuffer();

          synchronized (_timeBuffer) {
            System.arraycopy(data, 0, buffer, offset, sublen);
          }

          offset += sublen;
          break;

        case 'T':
          {
            long startTime = request.getStartTime();
            long endTime = Alarm.getCurrentTime();

            offset = print(buffer, offset, (int) ((endTime - startTime + 500) / 1000));
            break;
          }

        case 'D':
          {
            long startTime = request.getStartTime();
            long endTime = Alarm.getCurrentTime();

            offset = print(buffer, offset, (int) ((endTime - startTime) * 1000));
            break;
          }

        case 'u':
          value = request.getRemoteUser(false);
          if (value == null) buffer[offset++] = (byte) '-';
          else {
            buffer[offset++] = (byte) '"';
            offset = print(buffer, offset, value);
            buffer[offset++] = (byte) '"';
          }
          break;

        case 'v':
          value = request.getServerName();
          if (value == null) buffer[offset++] = (byte) '-';
          else {
            offset = print(buffer, offset, value);
          }
          break;

        case 'U':
          offset = print(buffer, offset, request.getRequestURI());
          break;

        default:
          throw new IOException();
      }
    }

    return offset;
  }