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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;
namespace System.Data.Linq.SqlClient {
// duplicates an expression up until a column or column ref is encountered
// goes 'deep' through alias ref's
// assumes that columnizing has been done already
internal class SqlExpander {
SqlFactory factory;
internal SqlExpander(SqlFactory factory) {
this.factory = factory;
}
internal SqlExpression Expand(SqlExpression exp) {
return (new Visitor(this.factory)).VisitExpression(exp);
}
class Visitor : SqlDuplicator.DuplicatingVisitor {
SqlFactory factory;
Expression sourceExpression;
internal Visitor(SqlFactory factory)
: base(true) {
this.factory = factory;
}
internal override SqlExpression VisitColumnRef(SqlColumnRef cref) {
return cref;
}
internal override SqlExpression VisitColumn(SqlColumn col) {
return new SqlColumnRef(col);
}
internal override SqlExpression VisitSharedExpression(SqlSharedExpression shared) {
return this.VisitExpression(shared.Expression);
}
internal override SqlExpression VisitSharedExpressionRef(SqlSharedExpressionRef sref) {
return this.VisitExpression(sref.SharedExpression.Expression);
}
internal override SqlExpression VisitAliasRef(SqlAliasRef aref) {
SqlNode node = aref.Alias.Node;
if (node is SqlTable || node is SqlTableValuedFunctionCall) {
return aref;
}
SqlUnion union = node as SqlUnion;
if (union != null) {
return this.ExpandUnion(union);
}
SqlSelect ss = node as SqlSelect;
if (ss != null) {
return this.VisitExpression(ss.Selection);
}
SqlExpression exp = node as SqlExpression;
if (exp != null)
return this.VisitExpression(exp);
throw Error.CouldNotHandleAliasRef(node.NodeType);
}
internal override SqlExpression VisitSubSelect(SqlSubSelect ss) {
return (SqlExpression)new SqlDuplicator().Duplicate(ss);
}
internal override SqlNode VisitLink(SqlLink link) {
SqlExpression expansion = this.VisitExpression(link.Expansion);
SqlExpression[] exprs = new SqlExpression[link.KeyExpressions.Count];
for (int i = 0, n = exprs.Length; i < n; i++) {
exprs[i] = this.VisitExpression(link.KeyExpressions[i]);
}
return new SqlLink(link.Id, link.RowType, link.ClrType, link.SqlType, link.Expression, link.Member, exprs, expansion, link.SourceExpression);
}
private SqlExpression ExpandUnion(SqlUnion union) {
List<SqlExpression> exprs = new List<SqlExpression>(2);
this.GatherUnionExpressions(union, exprs);
this.sourceExpression = union.SourceExpression;
SqlExpression result = this.ExpandTogether(exprs);
return result;
}
private void GatherUnionExpressions(SqlNode node, List<SqlExpression> exprs) {
SqlUnion union = node as SqlUnion;
if (union != null) {
this.GatherUnionExpressions(union.Left, exprs);
this.GatherUnionExpressions(union.Right, exprs);
}
else {
SqlSelect sel = node as SqlSelect;
if (sel != null) {
SqlAliasRef aref = sel.Selection as SqlAliasRef;
if (aref != null) {
this.GatherUnionExpressions(aref.Alias.Node, exprs);
}
else {
exprs.Add(sel.Selection);
}
}
}
}
[SuppressMessage("Microsoft.Performance", "CA1809:AvoidExcessiveLocals", 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.")]
[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.")]
[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 SqlExpression ExpandTogether(List<SqlExpression> exprs) {
switch (exprs[0].NodeType) {
case SqlNodeType.MethodCall: {
SqlMethodCall[] mcs = new SqlMethodCall[exprs.Count];
for (int i = 0; i < mcs.Length; ++i) {
mcs[i] = (SqlMethodCall)exprs[i];
}
List<SqlExpression> expandedArgs = new List<SqlExpression>();
for (int i = 0; i < mcs[0].Arguments.Count; ++i) {
List<SqlExpression> args = new List<SqlExpression>();
for (int j = 0; j < mcs.Length; ++j) {
args.Add(mcs[j].Arguments[i]);
}
SqlExpression expanded = this.ExpandTogether(args);
expandedArgs.Add(expanded);
}
return factory.MethodCall(mcs[0].Method, mcs[0].Object, expandedArgs.ToArray(), mcs[0].SourceExpression);
}
case SqlNodeType.ClientCase: {
// Are they all the same?
SqlClientCase[] scs = new SqlClientCase[exprs.Count];
scs[0] = (SqlClientCase)exprs[0];
for (int i = 1; i < scs.Length; ++i) {
scs[i] = (SqlClientCase)exprs[i];
}
// Expand expressions together.
List<SqlExpression> expressions = new List<SqlExpression>();
for (int i = 0; i < scs.Length; ++i) {
expressions.Add(scs[i].Expression);
}
SqlExpression expression = this.ExpandTogether(expressions);
// Expand individual expressions together.
List<SqlClientWhen> whens = new List<SqlClientWhen>();
for (int i = 0; i < scs[0].Whens.Count; ++i) {
List<SqlExpression> scos = new List<SqlExpression>();
for (int j = 0; j < scs.Length; ++j) {
SqlClientWhen when = scs[j].Whens[i];
scos.Add(when.Value);
}
whens.Add(new SqlClientWhen(scs[0].Whens[i].Match, this.ExpandTogether(scos)));
}
return new SqlClientCase(scs[0].ClrType, expression, whens, scs[0].SourceExpression);
}
case SqlNodeType.TypeCase: {
// Are they all the same?
SqlTypeCase[] tcs = new SqlTypeCase[exprs.Count];
tcs[0] = (SqlTypeCase)exprs[0];
for (int i = 1; i < tcs.Length; ++i) {
tcs[i] = (SqlTypeCase)exprs[i];
}
// Expand discriminators together.
List<SqlExpression> discriminators = new List<SqlExpression>();
for (int i = 0; i < tcs.Length; ++i) {
discriminators.Add(tcs[i].Discriminator);
}
SqlExpression discriminator = this.ExpandTogether(discriminators);
// Write expanded discriminators back in.
for (int i = 0; i < tcs.Length; ++i) {
tcs[i].Discriminator = discriminators[i];
}
// Expand individual type bindings together.
List<SqlTypeCaseWhen> whens = new List<SqlTypeCaseWhen>();
for (int i = 0; i < tcs[0].Whens.Count; ++i) {
List<SqlExpression> scos = new List<SqlExpression>();
for (int j = 0; j < tcs.Length; ++j) {
SqlTypeCaseWhen when = tcs[j].Whens[i];
scos.Add(when.TypeBinding);
}
SqlExpression expanded = this.ExpandTogether(scos);
whens.Add(new SqlTypeCaseWhen(tcs[0].Whens[i].Match, expanded));
}
return factory.TypeCase(tcs[0].ClrType, tcs[0].RowType, discriminator, whens, tcs[0].SourceExpression);
}
case SqlNodeType.New: {
// first verify all are similar client objects...
SqlNew[] cobs = new SqlNew[exprs.Count];
cobs[0] = (SqlNew)exprs[0];
for (int i = 1, n = exprs.Count; i < n; i++) {
if (exprs[i] == null || exprs[i].NodeType != SqlNodeType.New)
throw Error.UnionIncompatibleConstruction();
cobs[i] = (SqlNew)exprs[1];
if (cobs[i].Members.Count != cobs[0].Members.Count)
throw Error.UnionDifferentMembers();
for (int m = 0, mn = cobs[0].Members.Count; m < mn; m++) {
if (cobs[i].Members[m].Member != cobs[0].Members[m].Member) {
throw Error.UnionDifferentMemberOrder();
}
}
}
SqlMemberAssign[] bindings = new SqlMemberAssign[cobs[0].Members.Count];
for (int m = 0, mn = bindings.Length; m < mn; m++) {
List<SqlExpression> mexprs = new List<SqlExpression>();
for (int i = 0, n = exprs.Count; i < n; i++) {
mexprs.Add(cobs[i].Members[m].Expression);
}
bindings[m] = new SqlMemberAssign(cobs[0].Members[m].Member, this.ExpandTogether(mexprs));
for (int i = 0, n = exprs.Count; i < n; i++) {
cobs[i].Members[m].Expression = mexprs[i];
}
}
SqlExpression[] arguments = new SqlExpression[cobs[0].Args.Count];
for (int m = 0, mn = arguments.Length; m < mn; ++m) {
List<SqlExpression> mexprs = new List<SqlExpression>();
for (int i = 0, n = exprs.Count; i < n; i++) {
mexprs.Add(cobs[i].Args[m]);
}
arguments[m] = ExpandTogether(mexprs);
}
return factory.New(cobs[0].MetaType, cobs[0].Constructor, arguments, cobs[0].ArgMembers, bindings, exprs[0].SourceExpression);
}
case SqlNodeType.Link: {
SqlLink[] links = new SqlLink[exprs.Count];
links[0] = (SqlLink)exprs[0];
for (int i = 1, n = exprs.Count; i < n; i++) {
if (exprs[i] == null || exprs[i].NodeType != SqlNodeType.Link)
throw Error.UnionIncompatibleConstruction();
links[i] = (SqlLink)exprs[i];
if (links[i].KeyExpressions.Count != links[0].KeyExpressions.Count ||
links[i].Member != links[0].Member ||
(links[i].Expansion != null) != (links[0].Expansion != null))
throw Error.UnionIncompatibleConstruction();
}
SqlExpression[] kexprs = new SqlExpression[links[0].KeyExpressions.Count];
List<SqlExpression> lexprs = new List<SqlExpression>();
for (int k = 0, nk = links[0].KeyExpressions.Count; k < nk; k++) {
lexprs.Clear();
for (int i = 0, n = exprs.Count; i < n; i++) {
lexprs.Add(links[i].KeyExpressions[k]);
}
kexprs[k] = this.ExpandTogether(lexprs);
for (int i = 0, n = exprs.Count; i < n; i++) {
links[i].KeyExpressions[k] = lexprs[i];
}
}
SqlExpression expansion = null;
if (links[0].Expansion != null) {
lexprs.Clear();
for (int i = 0, n = exprs.Count; i < n; i++) {
lexprs.Add(links[i].Expansion);
}
expansion = this.ExpandTogether(lexprs);
for (int i = 0, n = exprs.Count; i < n; i++) {
links[i].Expansion = lexprs[i];
}
}
return new SqlLink(links[0].Id, links[0].RowType, links[0].ClrType, links[0].SqlType, links[0].Expression, links[0].Member, kexprs, expansion, links[0].SourceExpression);
}
case SqlNodeType.Value: {
/*
* ExprSet of all literals of the same value reduce to just a single literal.
*/
SqlValue val0 = (SqlValue)exprs[0];
for (int i = 1; i < exprs.Count; ++i) {
SqlValue val = (SqlValue)exprs[i];
if (!object.Equals(val.Value, val0.Value))
return this.ExpandIntoExprSet(exprs);
}
return val0;
}
case SqlNodeType.OptionalValue: {
if (exprs[0].SqlType.CanBeColumn) {
goto default;
}
List<SqlExpression> hvals = new List<SqlExpression>(exprs.Count);
List<SqlExpression> vals = new List<SqlExpression>(exprs.Count);
for (int i = 0, n = exprs.Count; i < n; i++) {
if (exprs[i] == null || exprs[i].NodeType != SqlNodeType.OptionalValue) {
throw Error.UnionIncompatibleConstruction();
}
SqlOptionalValue sov = (SqlOptionalValue)exprs[i];
hvals.Add(sov.HasValue);
vals.Add(sov.Value);
}
return new SqlOptionalValue(this.ExpandTogether(hvals), this.ExpandTogether(vals));
}
case SqlNodeType.OuterJoinedValue: {
if (exprs[0].SqlType.CanBeColumn) {
goto default;
}
List<SqlExpression> values = new List<SqlExpression>(exprs.Count);
for (int i = 0, n = exprs.Count; i < n; i++) {
if (exprs[i] == null || exprs[i].NodeType != SqlNodeType.OuterJoinedValue) {
throw Error.UnionIncompatibleConstruction();
}
SqlUnary su = (SqlUnary)exprs[i];
values.Add(su.Operand);
}
return factory.Unary(SqlNodeType.OuterJoinedValue, this.ExpandTogether(values));
}
case SqlNodeType.DiscriminatedType: {
SqlDiscriminatedType sdt0 = (SqlDiscriminatedType)exprs[0];
List<SqlExpression> foos = new List<SqlExpression>(exprs.Count);
foos.Add(sdt0.Discriminator);
for (int i = 1, n = exprs.Count; i < n; i++) {
SqlDiscriminatedType sdtN = (SqlDiscriminatedType)exprs[i];
if (sdtN.TargetType != sdt0.TargetType) {
throw Error.UnionIncompatibleConstruction();
}
foos.Add(sdtN.Discriminator);
}
return factory.DiscriminatedType(this.ExpandTogether(foos), ((SqlDiscriminatedType)exprs[0]).TargetType);
}
case SqlNodeType.ClientQuery:
case SqlNodeType.Multiset:
case SqlNodeType.Element:
case SqlNodeType.Grouping:
throw Error.UnionWithHierarchy();
default:
return this.ExpandIntoExprSet(exprs);
}
}
/// <summary>
/// Expand a set of expressions into a single expr set.
/// This is typically a fallback when there is no other way to unify a set of expressions.
/// </summary>
private SqlExpression ExpandIntoExprSet(List<SqlExpression> exprs) {
SqlExpression[] rexprs = new SqlExpression[exprs.Count];
for (int i = 0, n = exprs.Count; i < n; i++) {
rexprs[i] = this.VisitExpression(exprs[i]);
}
return this.factory.ExprSet(rexprs, this.sourceExpression);
}
}
}
}
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