Function ProcessNumberIndex

be/src/exprs/string-functions.cc:255–285

Process number in array selection. path_idx points at the start of the number in path_str. Return next unprocessed index in path_str. Return -1 for errors.

/// Process number in array selection. path_idx points at the start of the number in
/// path_str. Return next unprocessed index in path_str. Return -1 for errors.
static int ProcessNumberIndex(FunctionContext* ctx, const StringVal& path_str,
    int path_idx, JsonUdfValue* queue, JsonUdfAllocator* allocator) {
  const uint8_t* path = path_str.ptr;
  const char* number_start = reinterpret_cast<const char*>(path + path_idx);
  int i = path_idx;
  while (i < path_str.len && path[i] != ']') ++i;
  if (i == path_str.len) {
    string msg = Substitute("Unclosed brackets in json path '$0'",
        AnyValUtil::ToString(path_str));
    ctx->SetError(msg.c_str());
    return -1;
  }
  StringParser::ParseResult parse_res;
  int index = StringParser::StringToInt<int>(number_start, i - path_idx, &parse_res);
  if (parse_res != StringParser::PARSE_SUCCESS || index < 0) {
    const char* failure;
    if (parse_res == StringParser::PARSE_FAILURE) {
      failure = "Failed to parse json path '$0': Expected number at position $1";
    } else if (parse_res == StringParser::PARSE_OVERFLOW) {
      failure = "Failed to parse json path '$0': Index too large at position $1";
    } else {
      DCHECK(parse_res == StringParser::PARSE_SUCCESS && index < 0);
      failure = "Failed to parse json path '$0': Negative index at position $1";
    }
    string msg = Substitute(failure, AnyValUtil::ToString(path_str), path_idx);
    ctx->SetError(msg.c_str());
    return -1;
  }
  RETURN_IF_OOM(SelectByIndex(index, queue, allocator), -1);
  return i + 1;  // i points at ']'
}

/// Parse json_str into Document. Return false for errors.
static bool ParseStringVal(FunctionContext* ctx, const StringVal& json_str,