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//---------------------------------------------------------------------
// <copyright file="DefaultExpressionVisitor.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
namespace System.Data.Common.CommandTrees
{
using System;
using System.Collections.Generic;
using System.Data.Metadata.Edm;
using System.Diagnostics;
using System.Linq;
using CqtBuilder = System.Data.Common.CommandTrees.ExpressionBuilder.DbExpressionBuilder;
/// <summary>
/// Visits each element of an expression tree from a given root expression. If any element changes, the tree is
/// rebuilt back to the root and the new root expression is returned; otherwise the original root expression is returned.
/// </summary>
public class DefaultExpressionVisitor : DbExpressionVisitor<DbExpression>
{
private readonly Dictionary<DbVariableReferenceExpression, DbVariableReferenceExpression> varMappings = new Dictionary<DbVariableReferenceExpression, DbVariableReferenceExpression>();
protected DefaultExpressionVisitor()
{
}
protected virtual void OnExpressionReplaced(DbExpression oldExpression, DbExpression newExpression)
{
}
protected virtual void OnVariableRebound(DbVariableReferenceExpression fromVarRef, DbVariableReferenceExpression toVarRef)
{
}
protected virtual void OnEnterScope(IEnumerable<DbVariableReferenceExpression> scopeVariables)
{
}
protected virtual void OnExitScope()
{
}
protected virtual DbExpression VisitExpression(DbExpression expression)
{
DbExpression newValue = null;
if (expression != null)
{
newValue = expression.Accept<DbExpression>(this);
}
return newValue;
}
protected virtual IList<DbExpression> VisitExpressionList(IList<DbExpression> list)
{
return VisitList(list, this.VisitExpression);
}
protected virtual DbExpressionBinding VisitExpressionBinding(DbExpressionBinding binding)
{
DbExpressionBinding result = binding;
if (binding != null)
{
DbExpression newInput = this.VisitExpression(binding.Expression);
if (!object.ReferenceEquals(binding.Expression, newInput))
{
result = CqtBuilder.BindAs(newInput, binding.VariableName);
this.RebindVariable(binding.Variable, result.Variable);
}
}
return result;
}
protected virtual IList<DbExpressionBinding> VisitExpressionBindingList(IList<DbExpressionBinding> list)
{
return this.VisitList(list, this.VisitExpressionBinding);
}
protected virtual DbGroupExpressionBinding VisitGroupExpressionBinding(DbGroupExpressionBinding binding)
{
DbGroupExpressionBinding result = binding;
if (binding != null)
{
DbExpression newInput = this.VisitExpression(binding.Expression);
if (!object.ReferenceEquals(binding.Expression, newInput))
{
result = CqtBuilder.GroupBindAs(newInput, binding.VariableName, binding.GroupVariableName);
this.RebindVariable(binding.Variable, result.Variable);
this.RebindVariable(binding.GroupVariable, result.GroupVariable);
}
}
return result;
}
protected virtual DbSortClause VisitSortClause(DbSortClause clause)
{
DbSortClause result = clause;
if (clause != null)
{
DbExpression newExpression = this.VisitExpression(clause.Expression);
if (!object.ReferenceEquals(clause.Expression, newExpression))
{
if (!string.IsNullOrEmpty(clause.Collation))
{
result = (clause.Ascending ? CqtBuilder.ToSortClause(newExpression, clause.Collation) : CqtBuilder.ToSortClauseDescending(newExpression, clause.Collation));
}
else
{
result = (clause.Ascending ? CqtBuilder.ToSortClause(newExpression) : CqtBuilder.ToSortClauseDescending(newExpression));
}
}
}
return result;
}
protected virtual IList<DbSortClause> VisitSortOrder(IList<DbSortClause> sortOrder)
{
return VisitList(sortOrder, this.VisitSortClause);
}
protected virtual DbAggregate VisitAggregate(DbAggregate aggregate)
{
// Currently only function or group aggregate are possible
DbFunctionAggregate functionAggregate = aggregate as DbFunctionAggregate;
if (functionAggregate != null)
{
return VisitFunctionAggregate(functionAggregate);
}
DbGroupAggregate groupAggregate = (DbGroupAggregate)aggregate;
return VisitGroupAggregate(groupAggregate);
}
protected virtual DbFunctionAggregate VisitFunctionAggregate(DbFunctionAggregate aggregate)
{
DbFunctionAggregate result = aggregate;
if (aggregate != null)
{
EdmFunction newFunction = this.VisitFunction(aggregate.Function);
IList<DbExpression> newArguments = this.VisitExpressionList(aggregate.Arguments);
Debug.Assert(newArguments.Count == 1, "Function aggregate had more than one argument?");
if (!object.ReferenceEquals(aggregate.Function, newFunction) ||
!object.ReferenceEquals(aggregate.Arguments, newArguments))
{
if (aggregate.Distinct)
{
result = CqtBuilder.AggregateDistinct(newFunction, newArguments[0]);
}
else
{
result = CqtBuilder.Aggregate(newFunction, newArguments[0]);
}
}
}
return result;
}
protected virtual DbGroupAggregate VisitGroupAggregate(DbGroupAggregate aggregate)
{
DbGroupAggregate result = aggregate;
if (aggregate != null)
{
IList<DbExpression> newArguments = this.VisitExpressionList(aggregate.Arguments);
Debug.Assert(newArguments.Count == 1, "Group aggregate had more than one argument?");
if (!object.ReferenceEquals(aggregate.Arguments, newArguments))
{
result = CqtBuilder.GroupAggregate(newArguments[0]);
}
}
return result;
}
protected virtual DbLambda VisitLambda(DbLambda lambda)
{
EntityUtil.CheckArgumentNull(lambda, "lambda");
DbLambda result = lambda;
IList<DbVariableReferenceExpression> newFormals = this.VisitList(lambda.Variables, varRef =>
{
TypeUsage newVarType = this.VisitTypeUsage(varRef.ResultType);
if (!object.ReferenceEquals(varRef.ResultType, newVarType))
{
return CqtBuilder.Variable(newVarType, varRef.VariableName);
}
else
{
return varRef;
}
}
);
this.EnterScope(newFormals.ToArray()); // ToArray: Don't pass the List instance directly to OnEnterScope
DbExpression newBody = this.VisitExpression(lambda.Body);
this.ExitScope();
if (!object.ReferenceEquals(lambda.Variables, newFormals) ||
!object.ReferenceEquals(lambda.Body, newBody))
{
result = CqtBuilder.Lambda(newBody, newFormals);
}
return result;
}
// Metadata 'Visitor' methods
protected virtual EdmType VisitType(EdmType type) { return type; }
protected virtual TypeUsage VisitTypeUsage(TypeUsage type) { return type; }
protected virtual EntitySetBase VisitEntitySet(EntitySetBase entitySet) { return entitySet; }
protected virtual EdmFunction VisitFunction(EdmFunction functionMetadata) { return functionMetadata; }
#region Private Implementation
private void NotifyIfChanged(DbExpression originalExpression, DbExpression newExpression)
{
if (!object.ReferenceEquals(originalExpression, newExpression))
{
this.OnExpressionReplaced(originalExpression, newExpression);
}
}
private IList<TElement> VisitList<TElement>(IList<TElement> list, Func<TElement, TElement> map)
{
IList<TElement> result = list;
if(list != null)
{
List<TElement> newList = null;
for (int idx = 0; idx < list.Count; idx++)
{
TElement newElement = map(list[idx]);
if (newList == null &&
!object.ReferenceEquals(list[idx], newElement))
{
newList = new List<TElement>(list);
result = newList;
}
if (newList != null)
{
newList[idx] = newElement;
}
}
}
return result;
}
private DbExpression VisitUnary(DbUnaryExpression expression, Func<DbExpression, DbExpression> callback)
{
DbExpression result = expression;
DbExpression newArgument = this.VisitExpression(expression.Argument);
if (!object.ReferenceEquals(expression.Argument, newArgument))
{
result = callback(newArgument);
}
NotifyIfChanged(expression, result);
return result;
}
private DbExpression VisitTypeUnary(DbUnaryExpression expression, TypeUsage type, Func<DbExpression, TypeUsage, DbExpression> callback)
{
DbExpression result = expression;
DbExpression newArgument = this.VisitExpression(expression.Argument);
TypeUsage newType = this.VisitTypeUsage(type);
if (!object.ReferenceEquals(expression.Argument, newArgument) ||
!object.ReferenceEquals(type, newType))
{
result = callback(newArgument, newType);
}
NotifyIfChanged(expression, result);
return result;
}
private DbExpression VisitBinary(DbBinaryExpression expression, Func<DbExpression, DbExpression, DbExpression> callback)
{
DbExpression result = expression;
DbExpression newLeft = this.VisitExpression(expression.Left);
DbExpression newRight = this.VisitExpression(expression.Right);
if (!object.ReferenceEquals(expression.Left, newLeft) ||
!object.ReferenceEquals(expression.Right, newRight))
{
result = callback(newLeft, newRight);
}
NotifyIfChanged(expression, result);
return result;
}
private DbRelatedEntityRef VisitRelatedEntityRef(DbRelatedEntityRef entityRef)
{
RelationshipEndMember newSource;
RelationshipEndMember newTarget;
VisitRelationshipEnds(entityRef.SourceEnd, entityRef.TargetEnd, out newSource, out newTarget);
DbExpression newTargetRef = this.VisitExpression(entityRef.TargetEntityReference);
if (!object.ReferenceEquals(entityRef.SourceEnd, newSource) ||
!object.ReferenceEquals(entityRef.TargetEnd, newTarget) ||
!object.ReferenceEquals(entityRef.TargetEntityReference, newTargetRef))
{
return CqtBuilder.CreateRelatedEntityRef(newSource, newTarget, newTargetRef);
}
else
{
return entityRef;
}
}
private void VisitRelationshipEnds(RelationshipEndMember source, RelationshipEndMember target, out RelationshipEndMember newSource, out RelationshipEndMember newTarget)
{
//
Debug.Assert(source.DeclaringType.EdmEquals(target.DeclaringType), "Relationship ends not declared by same relationship type?");
RelationshipType mappedType = (RelationshipType)this.VisitType(target.DeclaringType);
newSource = mappedType.RelationshipEndMembers[source.Name];
newTarget = mappedType.RelationshipEndMembers[target.Name];
}
private DbExpression VisitTerminal(DbExpression expression, Func<TypeUsage, DbExpression> reconstructor)
{
DbExpression result = expression;
TypeUsage newType = this.VisitTypeUsage(expression.ResultType);
if (!object.ReferenceEquals(expression.ResultType, newType))
{
result = reconstructor(newType);
}
NotifyIfChanged(expression, result);
return result;
}
private void RebindVariable(DbVariableReferenceExpression from, DbVariableReferenceExpression to)
{
//
// The variable is only considered rebound if the name and/or type is different.
// Otherwise, the original variable reference and the new variable reference are
// equivalent, and no rebinding of references to the old variable is necessary.
//
// When considering the new/old result types, the TypeUsage instance may be equal
// or equivalent, but the EdmType must be the same instance, so that expressions
// such as a DbPropertyExpression with the DbVariableReferenceExpression as the Instance
// continue to be valid.
//
if (!from.VariableName.Equals(to.VariableName, StringComparison.Ordinal) ||
!object.ReferenceEquals(from.ResultType.EdmType, to.ResultType.EdmType) ||
!from.ResultType.EdmEquals(to.ResultType))
{
this.varMappings[from] = to;
this.OnVariableRebound(from, to);
}
}
private DbExpressionBinding VisitExpressionBindingEnterScope(DbExpressionBinding binding)
{
DbExpressionBinding result = this.VisitExpressionBinding(binding);
this.OnEnterScope(new[] { result.Variable });
return result;
}
private void EnterScope(params DbVariableReferenceExpression[] scopeVars)
{
this.OnEnterScope(scopeVars);
}
private void ExitScope()
{
this.OnExitScope();
}
#endregion
#region DbExpressionVisitor<DbExpression> Members
public override DbExpression Visit(DbExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
throw EntityUtil.NotSupported(System.Data.Entity.Strings.Cqt_General_UnsupportedExpression(expression.GetType().FullName));
}
public override DbExpression Visit(DbConstantExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
// Note that it is only safe to call DbConstantExpression.GetValue because the call to
// DbExpressionBuilder.Constant must clone immutable values (byte[]).
return VisitTerminal(expression, newType => CqtBuilder.Constant(newType, expression.GetValue()));
}
public override DbExpression Visit(DbNullExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitTerminal(expression, CqtBuilder.Null);
}
public override DbExpression Visit(DbVariableReferenceExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbVariableReferenceExpression newRef;
if (this.varMappings.TryGetValue(expression, out newRef))
{
result = newRef;
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbParameterReferenceExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitTerminal(expression, newType => CqtBuilder.Parameter(newType, expression.ParameterName));
}
public override DbExpression Visit(DbFunctionExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
IList<DbExpression> newArguments = this.VisitExpressionList(expression.Arguments);
EdmFunction newFunction = this.VisitFunction(expression.Function);
if (!object.ReferenceEquals(expression.Arguments, newArguments) ||
!object.ReferenceEquals(expression.Function, newFunction))
{
result = CqtBuilder.Invoke(newFunction, newArguments);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbLambdaExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
IList<DbExpression> newArguments = this.VisitExpressionList(expression.Arguments);
DbLambda newLambda = this.VisitLambda(expression.Lambda);
if (!object.ReferenceEquals(expression.Arguments, newArguments) ||
!object.ReferenceEquals(expression.Lambda, newLambda))
{
result = CqtBuilder.Invoke(newLambda, newArguments);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbPropertyExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbExpression newInstance = this.VisitExpression(expression.Instance);
if (!object.ReferenceEquals(expression.Instance, newInstance))
{
result = CqtBuilder.Property(newInstance, expression.Property.Name);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbComparisonExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
switch(expression.ExpressionKind)
{
case DbExpressionKind.Equals:
return this.VisitBinary(expression, CqtBuilder.Equal);
case DbExpressionKind.NotEquals:
return this.VisitBinary(expression, CqtBuilder.NotEqual);
case DbExpressionKind.GreaterThan:
return this.VisitBinary(expression, CqtBuilder.GreaterThan);
case DbExpressionKind.GreaterThanOrEquals:
return this.VisitBinary(expression, CqtBuilder.GreaterThanOrEqual);
case DbExpressionKind.LessThan:
return this.VisitBinary(expression, CqtBuilder.LessThan);
case DbExpressionKind.LessThanOrEquals:
return this.VisitBinary(expression, CqtBuilder.LessThanOrEqual);
default:
throw EntityUtil.NotSupported();
}
}
public override DbExpression Visit(DbLikeExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbExpression newArgument = this.VisitExpression(expression.Argument);
DbExpression newPattern = this.VisitExpression(expression.Pattern);
DbExpression newEscape = this.VisitExpression(expression.Escape);
if (!object.ReferenceEquals(expression.Argument, newArgument) ||
!object.ReferenceEquals(expression.Pattern, newPattern) ||
!object.ReferenceEquals(expression.Escape, newEscape))
{
result = CqtBuilder.Like(newArgument, newPattern, newEscape);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbLimitExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbExpression newArgument = this.VisitExpression(expression.Argument);
DbExpression newLimit = this.VisitExpression(expression.Limit);
if (!object.ReferenceEquals(expression.Argument, newArgument) ||
!object.ReferenceEquals(expression.Limit, newLimit))
{
Debug.Assert(!expression.WithTies, "Limit.WithTies == true?");
result = CqtBuilder.Limit(newArgument, newLimit);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbIsNullExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitUnary(expression, exp =>
{
if(TypeSemantics.IsRowType(exp.ResultType))
{
//
return CqtBuilder.CreateIsNullExpressionAllowingRowTypeArgument(exp);
}
else
{
return CqtBuilder.IsNull(exp);
}
}
);
}
public override DbExpression Visit(DbArithmeticExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
IList<DbExpression> newArguments = this.VisitExpressionList(expression.Arguments);
if (!object.ReferenceEquals(expression.Arguments, newArguments))
{
switch(expression.ExpressionKind)
{
case DbExpressionKind.Divide:
result = CqtBuilder.Divide(newArguments[0], newArguments[1]);
break;
case DbExpressionKind.Minus:
result = CqtBuilder.Minus(newArguments[0], newArguments[1]);
break;
case DbExpressionKind.Modulo:
result = CqtBuilder.Modulo(newArguments[0], newArguments[1]);
break;
case DbExpressionKind.Multiply:
result = CqtBuilder.Multiply(newArguments[0], newArguments[1]);
break;
case DbExpressionKind.Plus:
result = CqtBuilder.Plus(newArguments[0], newArguments[1]);
break;
case DbExpressionKind.UnaryMinus:
result = CqtBuilder.UnaryMinus(newArguments[0]);
break;
default:
throw EntityUtil.NotSupported();
}
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbAndExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitBinary(expression, CqtBuilder.And);
}
public override DbExpression Visit(DbOrExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitBinary(expression, CqtBuilder.Or);
}
public override DbExpression Visit(DbNotExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitUnary(expression, CqtBuilder.Not);
}
public override DbExpression Visit(DbDistinctExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitUnary(expression, CqtBuilder.Distinct);
}
public override DbExpression Visit(DbElementExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
Func<DbExpression, DbExpression> resultConstructor;
if (expression.IsSinglePropertyUnwrapped)
{
//
resultConstructor = CqtBuilder.CreateElementExpressionUnwrapSingleProperty;
}
else
{
resultConstructor = CqtBuilder.Element;
}
return VisitUnary(expression, resultConstructor);
}
public override DbExpression Visit(DbIsEmptyExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitUnary(expression, CqtBuilder.IsEmpty);
}
public override DbExpression Visit(DbUnionAllExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitBinary(expression, CqtBuilder.UnionAll);
}
public override DbExpression Visit(DbIntersectExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitBinary(expression, CqtBuilder.Intersect);
}
public override DbExpression Visit(DbExceptExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return VisitBinary(expression, CqtBuilder.Except);
}
public override DbExpression Visit(DbTreatExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return this.VisitTypeUnary(expression, expression.ResultType, CqtBuilder.TreatAs);
}
public override DbExpression Visit(DbIsOfExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
if (expression.ExpressionKind == DbExpressionKind.IsOfOnly)
{
return this.VisitTypeUnary(expression, expression.OfType, CqtBuilder.IsOfOnly);
}
else
{
return this.VisitTypeUnary(expression, expression.OfType, CqtBuilder.IsOf);
}
}
public override DbExpression Visit(DbCastExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return this.VisitTypeUnary(expression, expression.ResultType, CqtBuilder.CastTo);
}
public override DbExpression Visit(DbCaseExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
IList<DbExpression> newWhens = this.VisitExpressionList(expression.When);
IList<DbExpression> newThens = this.VisitExpressionList(expression.Then);
DbExpression newElse = this.VisitExpression(expression.Else);
if (!object.ReferenceEquals(expression.When, newWhens) ||
!object.ReferenceEquals(expression.Then, newThens) ||
!object.ReferenceEquals(expression.Else, newElse))
{
result = CqtBuilder.Case(newWhens, newThens, newElse);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbOfTypeExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
if (expression.ExpressionKind == DbExpressionKind.OfTypeOnly)
{
return this.VisitTypeUnary(expression, expression.OfType, CqtBuilder.OfTypeOnly);
}
else
{
return this.VisitTypeUnary(expression, expression.OfType, CqtBuilder.OfType);
}
}
public override DbExpression Visit(DbNewInstanceExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
TypeUsage newType = this.VisitTypeUsage(expression.ResultType);
IList<DbExpression> newArguments = this.VisitExpressionList(expression.Arguments);
bool unchanged = (object.ReferenceEquals(expression.ResultType, newType) && object.ReferenceEquals(expression.Arguments, newArguments));
if (expression.HasRelatedEntityReferences)
{
IList<DbRelatedEntityRef> newRefs = this.VisitList(expression.RelatedEntityReferences, this.VisitRelatedEntityRef);
if (!unchanged ||
!object.ReferenceEquals(expression.RelatedEntityReferences, newRefs))
{
result = CqtBuilder.CreateNewEntityWithRelationshipsExpression((EntityType)newType.EdmType, newArguments, newRefs);
}
}
else
{
if (!unchanged)
{
result = CqtBuilder.New(newType, System.Linq.Enumerable.ToArray(newArguments));
}
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbRefExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
EntityType targetType = (EntityType)TypeHelpers.GetEdmType<RefType>(expression.ResultType).ElementType;
DbExpression newArgument = this.VisitExpression(expression.Argument);
EntityType newType = (EntityType)this.VisitType(targetType);
EntitySet newSet = (EntitySet)this.VisitEntitySet(expression.EntitySet);
if (!object.ReferenceEquals(expression.Argument, newArgument) ||
!object.ReferenceEquals(targetType, newType) ||
!object.ReferenceEquals(expression.EntitySet, newSet))
{
result = CqtBuilder.RefFromKey(newSet, newArgument, newType);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbRelationshipNavigationExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
RelationshipEndMember newFrom;
RelationshipEndMember newTo;
VisitRelationshipEnds(expression.NavigateFrom, expression.NavigateTo, out newFrom, out newTo);
DbExpression newNavSource = this.VisitExpression(expression.NavigationSource);
if (!object.ReferenceEquals(expression.NavigateFrom, newFrom) ||
!object.ReferenceEquals(expression.NavigateTo, newTo) ||
!object.ReferenceEquals(expression.NavigationSource, newNavSource))
{
result = CqtBuilder.Navigate(newNavSource, newFrom, newTo);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbDerefExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return this.VisitUnary(expression, CqtBuilder.Deref);
}
public override DbExpression Visit(DbRefKeyExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return this.VisitUnary(expression, CqtBuilder.GetRefKey);
}
public override DbExpression Visit(DbEntityRefExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
return this.VisitUnary(expression, CqtBuilder.GetEntityRef);
}
public override DbExpression Visit(DbScanExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
EntitySetBase newSet = this.VisitEntitySet(expression.Target);
if (!object.ReferenceEquals(expression.Target, newSet))
{
result = CqtBuilder.Scan(newSet);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbFilterExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbExpressionBinding input = this.VisitExpressionBindingEnterScope(expression.Input);
DbExpression predicate = this.VisitExpression(expression.Predicate);
this.ExitScope();
if (!object.ReferenceEquals(expression.Input, input) ||
!object.ReferenceEquals(expression.Predicate, predicate))
{
result = CqtBuilder.Filter(input, predicate);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbProjectExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbExpressionBinding input = this.VisitExpressionBindingEnterScope(expression.Input);
DbExpression projection = this.VisitExpression(expression.Projection);
this.ExitScope();
if (!object.ReferenceEquals(expression.Input, input) ||
!object.ReferenceEquals(expression.Projection, projection))
{
result = CqtBuilder.Project(input, projection);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbCrossJoinExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
IList<DbExpressionBinding> newInputs = this.VisitExpressionBindingList(expression.Inputs);
if (!object.ReferenceEquals(expression.Inputs, newInputs))
{
result = CqtBuilder.CrossJoin(newInputs);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbJoinExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbExpressionBinding newLeft = this.VisitExpressionBinding(expression.Left);
DbExpressionBinding newRight = this.VisitExpressionBinding(expression.Right);
this.EnterScope(newLeft.Variable, newRight.Variable);
DbExpression newCondition = this.VisitExpression(expression.JoinCondition);
this.ExitScope();
if (!object.ReferenceEquals(expression.Left, newLeft) ||
!object.ReferenceEquals(expression.Right, newRight) ||
!object.ReferenceEquals(expression.JoinCondition, newCondition))
{
if (DbExpressionKind.InnerJoin == expression.ExpressionKind)
{
result = CqtBuilder.InnerJoin(newLeft, newRight, newCondition);
}
else if (DbExpressionKind.LeftOuterJoin == expression.ExpressionKind)
{
result = CqtBuilder.LeftOuterJoin(newLeft, newRight, newCondition);
}
else
{
Debug.Assert(expression.ExpressionKind == DbExpressionKind.FullOuterJoin, "DbJoinExpression had ExpressionKind other than InnerJoin, LeftOuterJoin or FullOuterJoin?");
result = CqtBuilder.FullOuterJoin(newLeft, newRight, newCondition);
}
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbApplyExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbExpressionBinding newInput = this.VisitExpressionBindingEnterScope(expression.Input);
DbExpressionBinding newApply = this.VisitExpressionBinding(expression.Apply);
this.ExitScope();
if (!object.ReferenceEquals(expression.Input, newInput) ||
!object.ReferenceEquals(expression.Apply, newApply))
{
if (DbExpressionKind.CrossApply == expression.ExpressionKind)
{
result = CqtBuilder.CrossApply(newInput, newApply);
}
else
{
Debug.Assert(expression.ExpressionKind == DbExpressionKind.OuterApply, "DbApplyExpression had ExpressionKind other than CrossApply or OuterApply?");
result = CqtBuilder.OuterApply(newInput, newApply);
}
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbGroupByExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbGroupExpressionBinding newInput = this.VisitGroupExpressionBinding(expression.Input);
this.EnterScope(newInput.Variable);
IList<DbExpression> newKeys = this.VisitExpressionList(expression.Keys);
this.ExitScope();
this.EnterScope(newInput.GroupVariable);
IList<DbAggregate> newAggs = this.VisitList<DbAggregate>(expression.Aggregates, this.VisitAggregate);
this.ExitScope();
if (!object.ReferenceEquals(expression.Input, newInput) ||
!object.ReferenceEquals(expression.Keys, newKeys) ||
!object.ReferenceEquals(expression.Aggregates, newAggs))
{
RowType groupOutput =
TypeHelpers.GetEdmType<RowType>(TypeHelpers.GetEdmType<CollectionType>(expression.ResultType).TypeUsage);
var boundKeys = groupOutput.Properties.Take(newKeys.Count).Select(p => p.Name).Zip(newKeys).ToList();
var boundAggs = groupOutput.Properties.Skip(newKeys.Count).Select(p => p.Name).Zip(newAggs).ToList();
result = CqtBuilder.GroupBy(newInput, boundKeys, boundAggs);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbSkipExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbExpressionBinding newInput = this.VisitExpressionBindingEnterScope(expression.Input);
IList<DbSortClause> newSortOrder = this.VisitSortOrder(expression.SortOrder);
this.ExitScope();
DbExpression newCount = this.VisitExpression(expression.Count);
if (!object.ReferenceEquals(expression.Input, newInput) ||
!object.ReferenceEquals(expression.SortOrder, newSortOrder) ||
!object.ReferenceEquals(expression.Count, newCount))
{
result = CqtBuilder.Skip(newInput, newSortOrder, newCount);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbSortExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbExpressionBinding newInput = this.VisitExpressionBindingEnterScope(expression.Input);
IList<DbSortClause> newSortOrder = this.VisitSortOrder(expression.SortOrder);
this.ExitScope();
if (!object.ReferenceEquals(expression.Input, newInput) ||
!object.ReferenceEquals(expression.SortOrder, newSortOrder))
{
result = CqtBuilder.Sort(newInput, newSortOrder);
}
NotifyIfChanged(expression, result);
return result;
}
public override DbExpression Visit(DbQuantifierExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbExpressionBinding input = this.VisitExpressionBindingEnterScope(expression.Input);
DbExpression predicate = this.VisitExpression(expression.Predicate);
this.ExitScope();
if (!object.ReferenceEquals(expression.Input, input) ||
!object.ReferenceEquals(expression.Predicate, predicate))
{
if (DbExpressionKind.All == expression.ExpressionKind)
{
result = CqtBuilder.All(input, predicate);
}
else
{
Debug.Assert(expression.ExpressionKind == DbExpressionKind.Any, "DbQuantifierExpression had ExpressionKind other than All or Any?");
result = CqtBuilder.Any(input, predicate);
}
}
NotifyIfChanged(expression, result);
return result;
}
#endregion
}
}
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