init - add project files

tools/jet-2.12.0/internal/jet/order_by_clause.go

@@ -0,0 +1,79 @@
+package jet
+
+// OrderByClause interface
+type OrderByClause interface {
+	// NULLS_FIRST specifies sort where null values appear before all non-null values.
+	// For some dialects(mysql,mariadb), which do not support NULL_FIRST, NULL_FIRST is simulated
+	// with additional IS_NOT_NULL expression.
+	// For instance,
+	//        Rental.ReturnDate.DESC().NULLS_FIRST()
+	// would translate to,
+	//        rental.return_date IS NOT NULL, rental.return_date DESC
+	NULLS_FIRST() OrderByClause
+
+	// NULLS_LAST specifies sort where null values appear after all non-null values.
+	// For some dialects(mysql,mariadb), which do not support NULLS_LAST, NULLS_LAST is simulated
+	// with additional IS_NULL expression.
+	// For instance,
+	//        Rental.ReturnDate.ASC().NULLS_LAST()
+	// would translate to,
+	//        rental.return_date IS NULL, rental.return_date ASC
+	NULLS_LAST() OrderByClause
+
+	serializeForOrderBy(statement StatementType, out *SQLBuilder)
+}
+
+type orderByClauseImpl struct {
+	expression Expression
+	ascending  *bool
+	nullsFirst *bool
+}
+
+func (ord *orderByClauseImpl) NULLS_FIRST() OrderByClause {
+	nullsFirst := true
+	ord.nullsFirst = &nullsFirst
+	return ord
+}
+func (ord *orderByClauseImpl) NULLS_LAST() OrderByClause {
+	nullsFirst := false
+	ord.nullsFirst = &nullsFirst
+	return ord
+}
+
+func (ord *orderByClauseImpl) serializeForOrderBy(statement StatementType, out *SQLBuilder) {
+	customSerializer := out.Dialect.SerializeOrderBy()
+	if customSerializer != nil {
+		customSerializer(ord.expression, ord.ascending, ord.nullsFirst)(statement, out)
+		return
+	}
+
+	if ord.expression == nil {
+		panic("jet: nil expression in ORDER BY clause")
+	}
+
+	ord.expression.serializeForOrderBy(statement, out)
+
+	if ord.ascending != nil {
+		if *ord.ascending {
+			out.WriteString("ASC")
+		} else {
+			out.WriteString("DESC")
+		}
+	}
+
+	if ord.nullsFirst != nil {
+		if *ord.nullsFirst {
+			out.WriteString("NULLS FIRST")
+		} else {
+			out.WriteString("NULLS LAST")
+		}
+	}
+}
+
+func newOrderByAscending(expression Expression, ascending bool) OrderByClause {
+	return &orderByClauseImpl{expression: expression, ascending: &ascending}
+}
+
+func newOrderByNullsFirst(expression Expression, nullsFirst bool) OrderByClause {
+	return &orderByClauseImpl{expression: expression, nullsFirst: &nullsFirst}
+}