code: private int nextXpathNodeSeperator() {
          int start = pos;
          boolean inQuote = false;
          char last = 0;
          do {
              if (queue.length() - start == 0) {
                  return -1;
              }
              Character c = queue.charAt(start++);
  
              if (last == 0 || last != ESC) {
                  if ((c.equals('\'') || c.equals('"')))
                      inQuote = !inQuote;
                  if (inQuote)
                      continue;
              }
  
              if (c == '/') {
                  return start;
              }
  
              last = c;
          } while (true);
      }
docs: 下一个"\"的位置,如果没有,则返回空,考虑转义和字符串文本