internal override Expression VisitParameter(ParameterExpression p)
{
if (ClientTypeUtil.TypeOrElementTypeIsEntity(p.Type))
{
if (p != this.builder.ParamExpressionInScope)
{
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjection(this.type, p.ToString()));
}
this.builder.StartNewPath();
}
return(p);
}
/// <summary>
/// Checks whether the specified <see cref="MethodCallExpression"/> refers
/// to a Select method call that works on the results of another Select call
/// </summary>
/// <param name="call">Method call expression to check.</param>
/// <param name="type">Type of the projection</param>
internal static void CheckChainedSequence(MethodCallExpression call, Type type)
{
if (ReflectionUtil.IsSequenceSelectMethod(call.Method))
{
// Chained Selects are not allowed
// c.Orders.Select(...).Select(...)
MethodCallExpression insideCall = ResourceBinder.StripTo <MethodCallExpression>(call.Arguments[0]);
if (insideCall != null && (ReflectionUtil.IsSequenceSelectMethod(insideCall.Method)))
{
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjection(type, call.ToString()));
}
}
}
/// <summary>
/// Visits a member access expression in non-entity projections, validating that
/// it's correct and recording the path visit to include in a projection if necessary.
/// </summary>
/// <param name="m">Expression to visit.</param>
/// <returns>The same expression.</returns>
/// <remarks>
/// The projection analyzer runs after funcletization, so a member expression
/// rather than a constant expression implies that this is correlated to
/// a parameter, by dotting through the argument in valid cases, and possibly
/// more complex cases in others like new DSC(p.Orders)*.Foo* <- .Foo is invalid.
/// </remarks>
internal override Expression VisitMemberAccess(MemberExpression m)
{
Debug.Assert(m != null, "m != null");
Type expressionType = m.Expression.Type;
this.leafExpressionIsMemberAccess = true;
// if primitive or nullable primitive, allow member access... i.e. calling Value on nullable<int>
if (PrimitiveType.IsKnownNullableType(expressionType))
{
this.leafExpressionIsMemberAccess = false;
return(base.VisitMemberAccess(m));
}
// Only allowed to project entities, also it is ok to do client side projections on complex types.
// Details on the fix for the Dev11 bug 350541 "Inconsistency between Count() method call and Count property projection on clr type collections":
// Relax check to only throw if IsCollectionProducingExpression returns true.
// This enables client side projections (for example "Count") on Clr type collections, like ReadOnlyCollection (which is used in spatial types), ICollection, IList, etc.
// We already allow client side method calls (like Linq extension method "Count()") on clr type collections, so it makes client side projections consistent.
// Note: it will still throw for List<T> (because IsCollectionProducingExpression returns true for List<T>),
// however this is consistent with how we handle MethodCallExpression on clr type collections
// and changing IsCollectionProducingExpression seems risky at this point as it's used in a lot of places.
if (IsCollectionProducingExpression(m.Expression))
{
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjection(this.type, m.ToString()));
}
PropertyInfo pi;
Expression boundTarget;
if (ResourceBinder.PatternRules.MatchNonPrivateReadableProperty(m, out pi, out boundTarget))
{
Expression e = base.VisitMemberAccess(m);
if (ClientTypeUtil.TypeOrElementTypeIsEntity(expressionType))
{
Type convertedType;
ResourceBinder.StripTo <Expression>(m.Expression, out convertedType);
this.builder.AppendPropertyToPath(pi, convertedType, this.context);
this.leafExpressionIsMemberAccess = false;
}
return(e);
}
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjection(this.type, m.ToString()));
}
internal override Expression VisitConditional(ConditionalExpression c)
{
var nullCheck = ResourceBinder.PatternRules.MatchNullCheck(this.builder.ParamExpressionInScope, c);
if (nullCheck.Match)
{
this.Visit(nullCheck.AssignExpression);
return(c);
}
if (ClientTypeUtil.TypeOrElementTypeIsEntity(c.Test.Type) ||
ClientTypeUtil.TypeOrElementTypeIsEntity(c.IfTrue.Type) ||
ClientTypeUtil.TypeOrElementTypeIsEntity(c.IfFalse.Type) ||
IsCollectionProducingExpression(c.Test) || IsCollectionProducingExpression(c.IfTrue) || IsCollectionProducingExpression(c.IfFalse))
{
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjection(this.type, c.ToString()));
}
return(base.VisitConditional(c));
}
/// <summary>Visits a unary expression while initializing a non-entity type structure.</summary>
/// <param name="u">Expression to visit.</param>
/// <returns>The visited expression.</returns>
internal override Expression VisitUnary(UnaryExpression u)
{
Debug.Assert(u != null, "u != null");
if (!ResourceBinder.PatternRules.MatchConvertToAssignable(u))
{
// In V3 while we support TypeAs conversions, we only support TypeAs before a MemberAccess and not TypeAs as the last operation
// i.e. we support "Manager = (p as Employee).Manager" (see VisitMemberAccess for detail), but we dont support "Manager = (p as Manager)"
// Note that the server also doesn't support a property path which ends with a type identifier.
if (u.NodeType == ExpressionType.TypeAs && this.leafExpressionIsMemberAccess)
{
return(base.VisitUnary(u));
}
if (ClientTypeUtil.TypeOrElementTypeIsEntity(u.Operand.Type))
{
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjection(this.type, u.ToString()));
}
}
return(base.VisitUnary(u));
}
internal override Expression VisitMethodCall(MethodCallExpression m)
{
// We throw NotSupportedException when IsDisallowedExceptionForMethodCall() is true
// or we have a method call on a non-entity type, for example c.MyCollectionComplexProperty.Select(...)
if ((m.Object != null && (IsDisallowedExpressionForMethodCall(m.Object, this.context.Model) || !ClientTypeUtil.TypeOrElementTypeIsEntity(m.Object.Type))) ||
m.Arguments.Any(a => IsDisallowedExpressionForMethodCall(a, this.context.Model)) ||
(m.Object == null && !ClientTypeUtil.TypeOrElementTypeIsEntity(m.Arguments[0].Type)))
{
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjection(this.type, m.ToString()));
}
if (ProjectionAnalyzer.IsMethodCallAllowedEntitySequence(m))
{
CheckChainedSequence(m, this.type);
// allow selects for following pattern:
// Orders = c.Orders.Select(o=> new NarrowOrder {...}).ToList();
return(base.VisitMethodCall(m));
}
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjectionToEntity(this.type, m.ToString()));
}
internal override Expression VisitMethodCall(MethodCallExpression m)
{
if ((m.Object != null && IsDisallowedExpressionForMethodCall(m.Object, this.context.Model)) ||
m.Arguments.Any(a => IsDisallowedExpressionForMethodCall(a, this.context.Model)))
{
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjection(this.type, m.ToString()));
}
CheckChainedSequence(m, this.type);
if (ProjectionAnalyzer.IsMethodCallAllowedEntitySequence(m))
{
// allow IEnum.Select and IEnum.ToList even if entity type.
return(base.VisitMethodCall(m));
}
if ((m.Object != null ? ClientTypeUtil.TypeOrElementTypeIsEntity(m.Object.Type) : false) ||
m.Arguments.Any(a => ClientTypeUtil.TypeOrElementTypeIsEntity(a.Type)))
{
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjection(this.type, m.ToString()));
}
return(base.VisitMethodCall(m));
}
/// <summary>Analyzes the specified member-init expression.</summary>
/// <param name="mie">Expression to analyze.</param>
/// <param name="pb">Path-tracking object to store analysis in.</param>
/// <param name="context">Context of expression to analyze.</param>
internal static void Analyze(MemberInitExpression mie, SelectExpandPathBuilder pb, DataServiceContext context)
{
Debug.Assert(mie != null, "mie != null");
var epa = new EntityProjectionAnalyzer(pb, mie.Type, context);
MemberAssignmentAnalysis targetEntityPath = null;
foreach (MemberBinding mb in mie.Bindings)
{
MemberAssignment ma = mb as MemberAssignment;
epa.Visit(ma.Expression);
if (ma != null)
{
var analysis = MemberAssignmentAnalysis.Analyze(pb.ParamExpressionInScope, ma.Expression);
if (analysis.IncompatibleAssignmentsException != null)
{
throw analysis.IncompatibleAssignmentsException;
}
// Note that an "empty" assignment on the binding is not checked/handled,
// because the funcletizer would have turned that into a constant
// in the tree, the visit earlier in this method would have thrown
// an exception at finding a constant in an entity projection.
//
// We do account however for failing to find a reference off the
// parameter entry to detect errors like this: new ET() { Ref = e }
// Here it looks like the new ET should be the parent of 'e', but
// there is nothing in scope that represents that.
//
// This also explains while error messages might be a bit misleading
// in this case (because they reference a constant when the user
// hasn't included any).
Type targetType = ClientTypeUtil.GetMemberType(ma.Member);
Expression[] lastExpressions = analysis.GetExpressionsBeyondTargetEntity();
if (lastExpressions.Length == 0)
{
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjectionToEntity(targetType, ma.Expression));
}
MemberExpression lastExpression = lastExpressions[lastExpressions.Length - 1] as MemberExpression;
Debug.Assert(
!analysis.MultiplePathsFound,
"!analysis.MultiplePathsFound -- the initilizer has been visited, and cannot be empty, and expressions that can combine paths should have thrown exception during initializer analysis");
#if DEBUG
Debug.Assert(
lastExpression != null,
"lastExpression != null -- the initilizer has been visited, and cannot be empty, and the only expressions that are allowed can be formed off the parameter, so this is always correlatd");
#endif
analysis.CheckCompatibleAssignments(mie.Type, ref targetEntityPath);
// For DataServiceStreamLink, the last expression will be a constant expression. Hence we won't be comparing name checks and entity checks for those type of bindings
if (lastExpression != null)
{
if (lastExpression.Member.Name != ma.Member.Name)
{
throw new NotSupportedException(Strings.ALinq_PropertyNamesMustMatchInProjections(lastExpression.Member.Name, ma.Member.Name));
}
// Unless we're initializing an entity, we should not traverse into the parameter in scope.
bool targetIsEntity = ClientTypeUtil.TypeOrElementTypeIsEntity(targetType);
bool sourceIsEntity = ClientTypeUtil.TypeOrElementTypeIsEntity(lastExpression.Type);
if (sourceIsEntity && !targetIsEntity)
{
throw new NotSupportedException(Strings.ALinq_ExpressionNotSupportedInProjection(targetType, ma.Expression));
}
}
}
}
}
