Method parse

sql/opt_histogram_json.cc:696–797

*/

bool Histogram_json_hb::parse(MEM_ROOT *mem_root, const char *db_name,
                              const char *table_name, Field *field,
                              const char *hist_data, size_t hist_data_len)
{
  json_engine_t je;
  int rc;
  const char *err= "JSON parse error";
  double total_size;
  int end_element;
  bool end_assigned;

  DBUG_ENTER("Histogram_json_hb::parse");

  mem_root_dynamic_array_init(mem_root, PSI_INSTRUMENT_MEM,
                              &je.stack, sizeof(int), NULL,
                              JSON_DEPTH_DEFAULT, JSON_DEPTH_INC, MYF(0));

  json_scan_start(&je, &my_charset_utf8mb4_bin,
                  (const uchar*)hist_data,
                  (const uchar*)hist_data+hist_data_len);

  if (json_scan_next(&je))
    goto err;

  if (je.state != JST_OBJ_START)
  {
    err= "Root JSON element must be a JSON object";
    goto err;
  }

  while (1)
  {
    if (json_scan_next(&je))
      goto err;
    if (je.state == JST_OBJ_END)
      break; // End of object

    if (je.state != JST_KEY)
      goto err; // Can' really have this: JSON object has keys in it

    Json_string hist_key_name(JSON_NAME);
    if (json_key_matches(&je, hist_key_name.get()))
    {
      total_size= 0.0;
      end_element= -1;
      if (json_scan_next(&je))
        goto err;

      if (je.state != JST_ARRAY_START)
      {
        err= "histogram_hb must contain an array";
        goto err;
      }

      while (!(rc= parse_bucket(&je, field, &total_size, &end_assigned, &err)))
      {
        if (end_assigned && end_element != -1)
          end_element= (int)buckets.size();