Function lookupNamedStructFields

rows.go:714–750

(
	t reflect.Type,
	fldDescs []pgconn.FieldDescription,
)

}

func lookupNamedStructFields(
	t reflect.Type,
	fldDescs []pgconn.FieldDescription,
) (*namedStructFields, error) {
	key := namedStructFieldsKey{
		t:        t,
		colNames: joinFieldNames(fldDescs),
	}
	if cached, ok := namedStructFieldMap.Load(key); ok {
		return cached.(*namedStructFields), nil
	}

	// We could probably do two-levels of caching, where we compute the key -> fields mapping
	// for a type only once, cache it by type, then use that to compute the column -> fields
	// mapping for a given set of columns.
	fieldStack := make([]int, 0, 1)
	fields, missingField := computeNamedStructFields(
		fldDescs,
		t,
		make([]structRowField, len(fldDescs)),
		&fieldStack,
	)
	for i, f := range fields {
		if f.path == nil {
			return nil, fmt.Errorf(
				"struct doesn't have corresponding row field %s",
				fldDescs[i].Name,
			)
		}
	}

	fieldsIface, _ := namedStructFieldMap.LoadOrStore(
		key,
		&namedStructFields{fields: fields, missingField: missingField},
	)
	return fieldsIface.(*namedStructFields), nil
}

func joinFieldNames(fldDescs []pgconn.FieldDescription) string {
	switch len(fldDescs) {