Function plpgsql_ns_lookup

src/pl/plpgsql/src/pl_funcs.c:129–187

---------- * plpgsql_ns_lookup Lookup an identifier in the given namespace chain * * Note that this only searches for variables, not labels. * * If localmode is true, only the topmost block level is searched. * * name1 must be non-NULL. Pass NULL for name2 and/or name3 if parsing a name * with fewer than three components. * * If names_used isn't NULL, *names_used receives the number of

 * ----------
 */
PLpgSQL_nsitem *
plpgsql_ns_lookup(PLpgSQL_nsitem *ns_cur, bool localmode,
				  const char *name1, const char *name2, const char *name3,
				  int *names_used)
{
	/* Outer loop iterates once per block level in the namespace chain */
	while (ns_cur != NULL)
	{
		PLpgSQL_nsitem *nsitem;

		/* Check this level for unqualified match to variable name */
		for (nsitem = ns_cur;
			 nsitem->itemtype != PLPGSQL_NSTYPE_LABEL;
			 nsitem = nsitem->prev)
		{
			if (strcmp(nsitem->name, name1) == 0)
			{
				if (name2 == NULL ||
					nsitem->itemtype != PLPGSQL_NSTYPE_VAR)
				{
					if (names_used)
						*names_used = 1;
					return nsitem;
				}
			}
		}

		/* Check this level for qualified match to variable name */
		if (name2 != NULL &&
			strcmp(nsitem->name, name1) == 0)
		{
			for (nsitem = ns_cur;
				 nsitem->itemtype != PLPGSQL_NSTYPE_LABEL;
				 nsitem = nsitem->prev)
			{
				if (strcmp(nsitem->name, name2) == 0)
				{
					if (name3 == NULL ||
						nsitem->itemtype != PLPGSQL_NSTYPE_VAR)
					{
						if (names_used)
							*names_used = 2;
						return nsitem;
					}
				}
			}
		}

		if (localmode)
			break;				/* do not look into upper levels */

		ns_cur = nsitem->prev;
	}

	/* This is just to suppress possibly-uninitialized-variable warnings */
	if (names_used)
		*names_used = 0;
	return NULL;				/* No match found */