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/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DLinq / Dlinq / SqlClient / Query / SqlColumnizer.cs / 1305376 / SqlColumnizer.cs
using System; using System.Collections.Generic; using System.Linq.Expressions; using System.Reflection; using System.Data.Linq; using System.Data.Linq.Mapping; using System.Data.Linq.Provider; using System.Linq; using System.Data.Linq.SqlClient; using System.Diagnostics.CodeAnalysis; using System.Diagnostics; namespace System.Data.Linq.SqlClient { // partions select expressions and common subexpressions into scalar and non-scalar pieces by // wrapping scalar pieces floating column nodes. internal class SqlColumnizer { ColumnNominator nominator; ColumnDeclarer declarer; internal SqlColumnizer() { this.nominator = new ColumnNominator(); this.declarer = new ColumnDeclarer(); } internal SqlExpression ColumnizeSelection(SqlExpression selection) { return this.declarer.Declare(selection, this.nominator.Nominate(selection)); } internal static bool CanBeColumn(SqlExpression expression) { return ColumnNominator.CanBeColumn(expression); } class ColumnDeclarer : SqlVisitor { HashSetcandidates; internal ColumnDeclarer() { } internal SqlExpression Declare(SqlExpression expression, HashSet candidates) { this.candidates = candidates; return (SqlExpression)this.Visit(expression); } internal override SqlNode Visit(SqlNode node) { SqlExpression expr = node as SqlExpression; if (expr != null) { if (this.candidates.Contains(expr)) { if (expr.NodeType == SqlNodeType.Column || expr.NodeType == SqlNodeType.ColumnRef) { return expr; } else { return new SqlColumn(expr.ClrType, expr.SqlType, null, null, expr, expr.SourceExpression); } } } return base.Visit(node); } } class ColumnNominator : SqlVisitor { bool isBlocked; HashSet candidates; internal HashSet Nominate(SqlExpression expression) { this.candidates = new HashSet (); this.isBlocked = false; this.Visit(expression); return this.candidates; } internal override SqlNode Visit(SqlNode node) { SqlExpression expression = node as SqlExpression; if (expression != null) { bool saveIsBlocked = this.isBlocked; this.isBlocked = false; if (CanRecurseColumnize(expression)) { base.Visit(expression); } if (!this.isBlocked) { if (CanBeColumn(expression)) { this.candidates.Add(expression); } else { this.isBlocked = true; } } this.isBlocked |= saveIsBlocked; } return node; } internal override SqlExpression VisitSimpleCase(SqlSimpleCase c) { c.Expression = this.VisitExpression(c.Expression); for (int i = 0, n = c.Whens.Count; i < n; i++) { // Don't walk down the match side. This can't be a column. c.Whens[i].Value = this.VisitExpression(c.Whens[i].Value); } return c; } internal override SqlExpression VisitTypeCase(SqlTypeCase tc) { tc.Discriminator = this.VisitExpression(tc.Discriminator); for (int i = 0, n = tc.Whens.Count; i < n; i++) { // Don't walk down the match side. This can't be a column. tc.Whens[i].TypeBinding = this.VisitExpression(tc.Whens[i].TypeBinding); } return tc; } internal override SqlExpression VisitClientCase(SqlClientCase c) { c.Expression = this.VisitExpression(c.Expression); for (int i = 0, n = c.Whens.Count; i < n; i++) { // Don't walk down the match side. This can't be a column. c.Whens[i].Value = this.VisitExpression(c.Whens[i].Value); } return c; } private static bool CanRecurseColumnize(SqlExpression expr) { switch (expr.NodeType) { case SqlNodeType.AliasRef: case SqlNodeType.ColumnRef: case SqlNodeType.Column: case SqlNodeType.Multiset: case SqlNodeType.Element: case SqlNodeType.ScalarSubSelect: case SqlNodeType.Exists: case SqlNodeType.ClientQuery: case SqlNodeType.SharedExpressionRef: case SqlNodeType.Link: case SqlNodeType.Nop: case SqlNodeType.Value: case SqlNodeType.Select: return false; default: return true; } } [SuppressMessage("Microsoft.Maintainability", "CA1502:AvoidExcessiveComplexity", Justification = "These issues are related to our use of if-then and case statements for node types, which adds to the complexity count however when reviewed they are easy to navigate and understand.")] private static bool IsClientOnly(SqlExpression expr) { switch (expr.NodeType) { case SqlNodeType.ClientCase: case SqlNodeType.TypeCase: case SqlNodeType.ClientArray: case SqlNodeType.Grouping: case SqlNodeType.DiscriminatedType: case SqlNodeType.SharedExpression: case SqlNodeType.SimpleExpression: case SqlNodeType.AliasRef: case SqlNodeType.Multiset: case SqlNodeType.Element: case SqlNodeType.ClientQuery: case SqlNodeType.SharedExpressionRef: case SqlNodeType.Link: case SqlNodeType.Nop: return true; case SqlNodeType.OuterJoinedValue: return IsClientOnly(((SqlUnary)expr).Operand); default: return false; } } internal static bool CanBeColumn(SqlExpression expression) { if (!IsClientOnly(expression) && expression.NodeType != SqlNodeType.Column && expression.SqlType.CanBeColumn) { switch (expression.NodeType) { case SqlNodeType.MethodCall: case SqlNodeType.Member: case SqlNodeType.New: return PostBindDotNetConverter.CanConvert(expression); default: return true; } } return false; } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. 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