Function json_locate_key

strings/json_lib.c:2315–2385

Expects the JSON object as an js argument, and the key name. Looks for this key in the object and returns the location of all the text related to it. The text includes the comma, separating this key. comma_pos - the hint where the comma is. It is important if you plan to replace the key rather than just cut. 1 - comma is on the left 2 - comma is on the right. 0 - no

  if no such key found *key_start is set to NULL.
*/
int json_locate_key(json_engine_t *je, const char *js, const char *js_end,
                    const char *kname,
                    const char **key_start, const char **key_end,
                    int *comma_pos)
{
  const char *kname_end= kname + strlen(kname);
  json_string_t key_name;
  int t_next, c_len, match_result;

  json_string_set_cs(&key_name, &my_charset_utf8mb4_bin);

  json_scan_start(je, &my_charset_utf8mb4_bin,(const uchar *) js,
                  (const uchar *) js_end);

  if (json_read_value(je) ||
      je->value_type != JSON_VALUE_OBJECT)
    goto err_return;

  *key_start= (const char *) je->s.c_str;
  *comma_pos= 0;

  while (!json_scan_next(je))
  {
    switch (je->state)
    {
    case JST_KEY:
      json_string_set_str(&key_name, (const uchar *) kname,
                          (const uchar *) kname_end);
      match_result= json_key_matches(je, &key_name);
      if (json_skip_key(je))
        goto err_return;
      get_first_nonspace(&je->s, &t_next, &c_len);
      je->s.c_str-= c_len;

      if (match_result)
      {
        *key_end= (const char *) je->s.c_str;

        if (*comma_pos == 1)
        {
          return 0;
        }

        DBUG_ASSERT(*comma_pos == 0);

        if (t_next == C_COMMA)
        {
          *key_end+= c_len;
          *comma_pos= 2;
        }
        else if (t_next == C_RCURB)
          *comma_pos= 0;
        else
          goto err_return;
        return 0;
      }

      *key_start= (const char *) je->s.c_str;