Function exec_move_row

src/pl/plpgsql/src/pl_exec.c:6676–6806

* exec_move_row Move one tuple's values into a record or row * * tup and tupdesc may both be NULL if we're just assigning an indeterminate * composite NULL to the target. Alternatively, can have tup be NULL and * tupdesc not NULL, in which case we assign a row of NULLs to the target. * * Since this uses the mcontext for workspace, caller should eventually call * exec_eval_cleanup to prev

 * exec_eval_cleanup to prevent long-term memory leaks.
 */
static void
exec_move_row(PLpgSQL_execstate *estate,
			  PLpgSQL_variable *target,
			  HeapTuple tup, TupleDesc tupdesc)
{
	ExpandedRecordHeader *newerh = NULL;

	/*
	 * If target is RECORD, we may be able to avoid field-by-field processing.
	 */
	if (target->dtype == PLPGSQL_DTYPE_REC)
	{
		PLpgSQL_rec *rec = (PLpgSQL_rec *) target;

		/*
		 * If we have no source tupdesc, just set the record variable to NULL.
		 * (If we have a source tupdesc but not a tuple, we'll set the
		 * variable to a row of nulls, instead.  This is odd perhaps, but
		 * backwards compatible.)
		 */
		if (tupdesc == NULL)
		{
			if (rec->datatype &&
				rec->datatype->typtype == TYPTYPE_DOMAIN)
			{
				/*
				 * If it's a composite domain, NULL might not be a legal
				 * value, so we instead need to make an empty expanded record
				 * and ensure that domain type checking gets done.  If there
				 * is already an expanded record, piggyback on its lookups.
				 */
				newerh = make_expanded_record_for_rec(estate, rec,
													  NULL, rec->erh);
				expanded_record_set_tuple(newerh, NULL, false, false);
				assign_record_var(estate, rec, newerh);
			}
			else
			{
				/* Just clear it to NULL */
				if (rec->erh)
					DeleteExpandedObject(ExpandedRecordGetDatum(rec->erh));
				rec->erh = NULL;
			}
			return;
		}

		/*
		 * Build a new expanded record with appropriate tupdesc.
		 */
		newerh = make_expanded_record_for_rec(estate, rec, tupdesc, NULL);

		/*
		 * If the rowtypes match, or if we have no tuple anyway, we can
		 * complete the assignment without field-by-field processing.
		 *
		 * The tests here are ordered more or less in order of cheapness.  We
		 * can easily detect it will work if the target is declared RECORD or
		 * has the same typeid as the source.  But when assigning from a query