Function findLimitInsertPosition

backend/plugin/db/pg/query.go:282–302

findLimitInsertPosition returns the byte offset where " LIMIT N" should be inserted, and whether the insertion is before a locking clause (FOR UPDATE/SHARE).

(sel *ast.SelectStmt)

// findLimitInsertPosition returns the byte offset where " LIMIT N" should be inserted,
// and whether the insertion is before a locking clause (FOR UPDATE/SHARE).
func findLimitInsertPosition(sel *ast.SelectStmt) (int, bool) {
	// LIMIT must appear before FOR UPDATE/SHARE.
	if sel.LockingClause != nil {
		span := ast.ListSpan(sel.LockingClause)
		if span.Start > 0 {
			return span.Start, true
		}
	}

	// Otherwise insert at SelectStmt.Loc.End (after everything, including outer parens).
	// For CTE queries, omni may report SelectStmt.Loc.End before the outer ORDER BY,
	// so account for the sort clause explicitly.
	end := sel.Loc.End
	if span := ast.ListSpan(sel.SortClause); span.End > end {
		end = span.End
	}
	if end <= 0 {
		return 0, false
	}
	return end, false
}

// extractIntFromNode extracts an integer value from a LIMIT/OFFSET node.
func extractIntFromNode(node ast.Node) int {