Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Data.Linq/SqlClient/Query/SqlTopReducer.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using System.Linq.Expressions;
+using System.Reflection;
+using System.Data.Linq;
+using System.Data.Linq.Provider;
+using System.Linq;
+
+namespace System.Data.Linq.SqlClient {
+
+    internal class SqlTopReducer {
+
+        internal static SqlNode Reduce(SqlNode node, SqlNodeAnnotations annotations, SqlFactory sql) {
+            return new Visitor(annotations, sql).Visit(node);
+        }
+
+        class Visitor : SqlVisitor {
+            SqlNodeAnnotations annotations;
+            SqlFactory sql;
+
+            internal Visitor(SqlNodeAnnotations annotations, SqlFactory sql) {
+                this.annotations = annotations;
+                this.sql = sql;
+            }
+
+            internal override SqlSelect VisitSelect(SqlSelect select) {
+                base.VisitSelect(select);
+                if (select.Top != null) {
+                    if (select.Top.NodeType == SqlNodeType.Value) {
+                        SqlValue val = (SqlValue)select.Top;
+                        // convert to literal value for SQL2K compatibility
+                        if (val.IsClientSpecified) {
+                            select.Top = sql.Value(val.ClrType, val.SqlType, val.Value, false, val.SourceExpression);
+                        }
+                    }
+                    else {
+                        // cannot be converted to literal value. note that this select is not SQL2K compatible
+                        this.annotations.Add(select.Top, new SqlServerCompatibilityAnnotation(Strings.SourceExpressionAnnotation(select.Top.SourceExpression), SqlProvider.ProviderMode.Sql2000));
+                    }
+                }
+                return select;
+            }
+        }
+    }
+}