std::string Configuration::SubstituteVars()

in src/hbase/client/configuration.cc [49:90]

• 29 lines of code
• 7 McCabe index (conditional complexity)

std::string Configuration::SubstituteVars(const std::string &expr) const {
  if (0 == expr.size()) return expr;

  std::string eval(expr);
  std::string value_to_be_replaced("");
  std::string var("");
  for (int i = 0; i < kMaxSubsts; i++) {
    var = "";
    size_t start_pos = IsSubVariable(eval, var);
    if (start_pos != std::string::npos) {
      // We are blindly checking for environment property at first.
      // If we don't get any value from GetEnv, check in hbase-site.xml.
      value_to_be_replaced = GetEnv(var).value_or(GetProperty(var).value_or(""));

      // we haven't found any value yet so we are returning eval
      if (0 == value_to_be_replaced.size()) {
        return eval;
      }

      // return original expression if there is a loop
      if (value_to_be_replaced == expr) {
        return expr;
      }

      eval.replace(start_pos, var.size() + 3, value_to_be_replaced);

    } else {
      // No further expansion required.
      return eval;
    }
  }
  // We reached here if the loop is exhausted
  // If MAX_SUBSTS is exhausted, check if more variable substitution is reqd.
  // If any-more substitutions are reqd, throw an error.
  var = "";
  if (IsSubVariable(eval, var) != std::string::npos) {
    throw std::runtime_error("Variable substitution depth too large: " +
                             std::to_string(kMaxSubsts) + " " + expr);
  } else {
    return eval;
  }
}