304 lines
15 KiB
C#
304 lines
15 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Data.Linq;
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using System.Diagnostics.CodeAnalysis;
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namespace System.Data.Linq.SqlClient {
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/// <summary>
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/// Compare two trees for value equality. Implemented as a parallel visitor.
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/// </summary>
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internal class SqlComparer {
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internal SqlComparer() {
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}
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[SuppressMessage("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily", Justification = "Microsoft: Cast is dependent on node type and casts do not happen unecessarily in a single code path.")]
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[SuppressMessage("Microsoft.Maintainability", "CA1506:AvoidExcessiveClassCoupling", 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.")]
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[SuppressMessage("Microsoft.Maintainability", "CA1505:AvoidUnmaintainableCode", 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.")]
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[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.")]
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internal static bool AreEqual(SqlNode node1, SqlNode node2) {
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if (node1 == node2)
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return true;
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if (node1 == null || node2 == null)
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return false;
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if (node1.NodeType == SqlNodeType.SimpleCase)
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node1 = UnwrapTrivialCaseExpression((SqlSimpleCase)node1);
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if (node2.NodeType == SqlNodeType.SimpleCase)
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node2 = UnwrapTrivialCaseExpression((SqlSimpleCase)node2);
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if (node1.NodeType != node2.NodeType) {
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// allow expression sets to compare against single expressions
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if (node1.NodeType == SqlNodeType.ExprSet) {
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SqlExprSet eset = (SqlExprSet)node1;
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for (int i = 0, n = eset.Expressions.Count; i < n; i++) {
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if (AreEqual(eset.Expressions[i], node2))
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return true;
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}
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}
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else if (node2.NodeType == SqlNodeType.ExprSet) {
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SqlExprSet eset = (SqlExprSet)node2;
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for (int i = 0, n = eset.Expressions.Count; i < n; i++) {
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if (AreEqual(node1, eset.Expressions[i]))
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return true;
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}
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}
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return false;
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}
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if (node1.Equals(node2))
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return true;
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switch (node1.NodeType) {
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case SqlNodeType.Not:
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case SqlNodeType.Not2V:
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case SqlNodeType.Negate:
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case SqlNodeType.BitNot:
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case SqlNodeType.IsNull:
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case SqlNodeType.IsNotNull:
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case SqlNodeType.Count:
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case SqlNodeType.Max:
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case SqlNodeType.Min:
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case SqlNodeType.Sum:
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case SqlNodeType.Avg:
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case SqlNodeType.Stddev:
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case SqlNodeType.ValueOf:
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case SqlNodeType.OuterJoinedValue:
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case SqlNodeType.ClrLength:
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return AreEqual(((SqlUnary)node1).Operand, ((SqlUnary)node2).Operand);
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case SqlNodeType.Add:
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case SqlNodeType.Sub:
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case SqlNodeType.Mul:
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case SqlNodeType.Div:
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case SqlNodeType.Mod:
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case SqlNodeType.BitAnd:
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case SqlNodeType.BitOr:
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case SqlNodeType.BitXor:
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case SqlNodeType.And:
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case SqlNodeType.Or:
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case SqlNodeType.GE:
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case SqlNodeType.GT:
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case SqlNodeType.LE:
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case SqlNodeType.LT:
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case SqlNodeType.EQ:
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case SqlNodeType.NE:
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case SqlNodeType.EQ2V:
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case SqlNodeType.NE2V:
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case SqlNodeType.Concat:
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SqlBinary firstNode = (SqlBinary)node1;
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SqlBinary secondNode = (SqlBinary)node2;
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return AreEqual(firstNode.Left, secondNode.Left)
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&& AreEqual(firstNode.Right, secondNode.Right);
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case SqlNodeType.Convert:
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case SqlNodeType.Treat: {
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SqlUnary sun1 = (SqlUnary)node1;
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SqlUnary sun2 = (SqlUnary)node2;
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return sun1.ClrType == sun2.ClrType && sun1.SqlType == sun2.SqlType && AreEqual(sun1.Operand, sun2.Operand);
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}
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case SqlNodeType.Between: {
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SqlBetween b1 = (SqlBetween)node1;
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SqlBetween b2 = (SqlBetween)node1;
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return AreEqual(b1.Expression, b2.Expression) &&
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AreEqual(b1.Start, b2.Start) &&
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AreEqual(b1.End, b2.End);
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}
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case SqlNodeType.Parameter:
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return node1 == node2;
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case SqlNodeType.Alias:
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return AreEqual(((SqlAlias)node1).Node, ((SqlAlias)node2).Node);
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case SqlNodeType.AliasRef:
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return AreEqual(((SqlAliasRef)node1).Alias, ((SqlAliasRef)node2).Alias);
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case SqlNodeType.Column:
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SqlColumn col1 = (SqlColumn)node1;
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SqlColumn col2 = (SqlColumn)node2;
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return col1 == col2 || (col1.Expression != null && col2.Expression != null && AreEqual(col1.Expression, col2.Expression));
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case SqlNodeType.Table:
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return ((SqlTable)node1).MetaTable == ((SqlTable)node2).MetaTable;
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case SqlNodeType.Member:
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return (((SqlMember)node1).Member == ((SqlMember)node2).Member) &&
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AreEqual(((SqlMember)node1).Expression, ((SqlMember)node2).Expression);
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case SqlNodeType.ColumnRef:
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SqlColumnRef cref1 = (SqlColumnRef)node1;
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SqlColumnRef cref2 = (SqlColumnRef)node2;
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return GetBaseColumn(cref1) == GetBaseColumn(cref2);
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case SqlNodeType.Value:
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return Object.Equals(((SqlValue)node1).Value, ((SqlValue)node2).Value);
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case SqlNodeType.TypeCase: {
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SqlTypeCase c1 = (SqlTypeCase)node1;
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SqlTypeCase c2 = (SqlTypeCase)node2;
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if (!AreEqual(c1.Discriminator, c2.Discriminator)) {
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return false;
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}
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if (c1.Whens.Count != c2.Whens.Count) {
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return false;
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}
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for (int i = 0, c = c1.Whens.Count; i < c; ++i) {
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if (!AreEqual(c1.Whens[i].Match, c2.Whens[i].Match)) {
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return false;
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}
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if (!AreEqual(c1.Whens[i].TypeBinding, c2.Whens[i].TypeBinding)) {
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return false;
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}
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}
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return true;
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}
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case SqlNodeType.SearchedCase: {
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SqlSearchedCase c1 = (SqlSearchedCase)node1;
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SqlSearchedCase c2 = (SqlSearchedCase)node2;
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if (c1.Whens.Count != c2.Whens.Count)
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return false;
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for (int i = 0, n = c1.Whens.Count; i < n; i++) {
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if (!AreEqual(c1.Whens[i].Match, c2.Whens[i].Match) ||
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!AreEqual(c1.Whens[i].Value, c2.Whens[i].Value))
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return false;
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}
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return AreEqual(c1.Else, c2.Else);
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}
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case SqlNodeType.ClientCase: {
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SqlClientCase c1 = (SqlClientCase)node1;
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SqlClientCase c2 = (SqlClientCase)node2;
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if (c1.Whens.Count != c2.Whens.Count)
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return false;
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for (int i = 0, n = c1.Whens.Count; i < n; i++) {
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if (!AreEqual(c1.Whens[i].Match, c2.Whens[i].Match) ||
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!AreEqual(c1.Whens[i].Value, c2.Whens[i].Value))
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return false;
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}
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return true;
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}
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case SqlNodeType.DiscriminatedType: {
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SqlDiscriminatedType dt1 = (SqlDiscriminatedType)node1;
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SqlDiscriminatedType dt2 = (SqlDiscriminatedType)node2;
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return AreEqual(dt1.Discriminator, dt2.Discriminator);
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}
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case SqlNodeType.SimpleCase: {
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SqlSimpleCase c1 = (SqlSimpleCase)node1;
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SqlSimpleCase c2 = (SqlSimpleCase)node2;
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if (c1.Whens.Count != c2.Whens.Count)
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return false;
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for (int i = 0, n = c1.Whens.Count; i < n; i++) {
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if (!AreEqual(c1.Whens[i].Match, c2.Whens[i].Match) ||
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!AreEqual(c1.Whens[i].Value, c2.Whens[i].Value))
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return false;
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}
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return true;
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}
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case SqlNodeType.Like: {
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SqlLike like1 = (SqlLike)node1;
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SqlLike like2 = (SqlLike)node2;
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return AreEqual(like1.Expression, like2.Expression) &&
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AreEqual(like1.Pattern, like2.Pattern) &&
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AreEqual(like1.Escape, like2.Escape);
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}
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case SqlNodeType.Variable: {
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SqlVariable v1 = (SqlVariable)node1;
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SqlVariable v2 = (SqlVariable)node2;
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return v1.Name == v2.Name;
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}
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case SqlNodeType.FunctionCall: {
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SqlFunctionCall f1 = (SqlFunctionCall)node1;
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SqlFunctionCall f2 = (SqlFunctionCall)node2;
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if (f1.Name != f2.Name)
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return false;
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if (f1.Arguments.Count != f2.Arguments.Count)
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return false;
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for (int i = 0, n = f1.Arguments.Count; i < n; i++) {
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if (!AreEqual(f1.Arguments[i], f2.Arguments[i]))
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return false;
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}
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return true;
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}
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case SqlNodeType.Link: {
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SqlLink l1 = (SqlLink)node1;
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SqlLink l2 = (SqlLink)node2;
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if (!MetaPosition.AreSameMember(l1.Member.Member, l2.Member.Member)) {
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return false;
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}
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if (!AreEqual(l1.Expansion, l2.Expansion)) {
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return false;
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}
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if (l1.KeyExpressions.Count != l2.KeyExpressions.Count) {
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return false;
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}
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for (int i = 0, c = l1.KeyExpressions.Count; i < c; ++i) {
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if (!AreEqual(l1.KeyExpressions[i], l2.KeyExpressions[i])) {
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return false;
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}
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}
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return true;
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}
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case SqlNodeType.ExprSet:
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SqlExprSet es1 = (SqlExprSet)node1;
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SqlExprSet es2 = (SqlExprSet)node2;
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if (es1.Expressions.Count != es2.Expressions.Count)
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return false;
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for(int i = 0, n = es1.Expressions.Count; i < n; i++) {
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if (!AreEqual(es1.Expressions[i], es2.Expressions[i]))
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return false;
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}
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return true;
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case SqlNodeType.OptionalValue:
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SqlOptionalValue ov1 = (SqlOptionalValue)node1;
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SqlOptionalValue ov2 = (SqlOptionalValue)node2;
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return AreEqual(ov1.Value, ov2.Value);
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case SqlNodeType.Row:
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case SqlNodeType.UserQuery:
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case SqlNodeType.StoredProcedureCall:
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case SqlNodeType.UserRow:
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case SqlNodeType.UserColumn:
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case SqlNodeType.Multiset:
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case SqlNodeType.ScalarSubSelect:
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case SqlNodeType.Element:
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case SqlNodeType.Exists:
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case SqlNodeType.Join:
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case SqlNodeType.Select:
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case SqlNodeType.New:
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case SqlNodeType.ClientQuery:
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case SqlNodeType.ClientArray:
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case SqlNodeType.Insert:
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case SqlNodeType.Update:
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case SqlNodeType.Delete:
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case SqlNodeType.MemberAssign:
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case SqlNodeType.Assign:
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case SqlNodeType.Block:
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case SqlNodeType.Union:
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case SqlNodeType.DoNotVisit:
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case SqlNodeType.MethodCall:
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case SqlNodeType.Nop:
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default:
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return false;
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}
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}
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private static SqlColumn GetBaseColumn(SqlColumnRef cref) {
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while (cref != null && cref.Column.Expression != null) {
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SqlColumnRef cr = cref.Column.Expression as SqlColumnRef;
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if (cr != null) {
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cref = cr;
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continue;
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}
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else {
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break;
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}
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}
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return cref.Column;
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}
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private static SqlExpression UnwrapTrivialCaseExpression(SqlSimpleCase sc) {
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if (sc.Whens.Count != 1) {
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return sc;
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}
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if (!SqlComparer.AreEqual(sc.Expression, sc.Whens[0].Match)) {
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return sc;
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}
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SqlExpression result = sc.Whens[0].Value;
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if (result.NodeType == SqlNodeType.SimpleCase) {
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return UnwrapTrivialCaseExpression((SqlSimpleCase)result);
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}
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return result;
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}
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}
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}
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