/// <summary>
/// If there is a MemberInitExpression 'new Person { ID = p.ID, Friend = new Person { ID = p.Friend.ID }}'
/// or a NewExpression 'new { ID = p.ID, Friend = new { ID = p.Friend.ID }}',
/// this method validates against the RHS of the member assignment, the expression "p.ID" for example.
/// </summary>
/// <param name="expressionToAssign">The expression to validate.</param>
/// <param name="initType">Type of the MemberInit or the New expression.</param>
/// <param name="previousNested">The outer nested initializer of the current initializer we are checking.</param>
/// <returns>true if the expression to assign is fine; false otherwise.</returns>
private bool CheckCompatibleAssignmentExpression(Expression expressionToAssign, Type initType, ref MemberAssignmentAnalysis previousNested)
{
MemberAssignmentAnalysis nested = MemberAssignmentAnalysis.Analyze(this.entity, expressionToAssign);
if (nested.MultiplePathsFound)
{
this.multiplePathsFound = true;
return(false);
}
// When we're visiting a nested entity initializer, we're exactly one level above that.
Exception incompatibleException = nested.CheckCompatibleAssignments(initType, ref previousNested);
if (incompatibleException != null)
{
this.incompatibleAssignmentsException = incompatibleException;
return(false);
}
if (this.pathFromEntity.Count == 0)
{
this.pathFromEntity.AddRange(nested.GetExpressionsToTargetEntity());
}
return(true);
}
/// <summary>Analyzes an assignment from a member-init expression.</summary>
/// <param name="entityInScope">Entity in scope for the lambda that's providing the parameter.</param>
/// <param name="assignmentExpression">The expression to analyze.</param>
/// <returns>The analysis results.</returns>
internal static MemberAssignmentAnalysis Analyze(Expression entityInScope, Expression assignmentExpression)
{
Debug.Assert(entityInScope != null, "entityInScope != null");
Debug.Assert(assignmentExpression != null, "assignmentExpression != null");
MemberAssignmentAnalysis result = new MemberAssignmentAnalysis(entityInScope);
result.Visit(assignmentExpression);
return(result);
}
/// <summary>
/// Checks whether the this and a <paramref name="previous"/>
/// paths for assignments are compatible.
/// </summary>
/// <param name="targetType">Type being initialized.</param>
/// <param name="previous">Previously seen member accesses (null if this is the first).</param>
/// <returns>An exception to be thrown if assignments are not compatible; null otherwise.</returns>
/// <remarks>
/// This method does not set the IncompatibleAssignmentsException property on either
/// analysis instance.
/// </remarks>
internal Exception CheckCompatibleAssignments(Type targetType, ref MemberAssignmentAnalysis previous)
{
if (previous == null)
{
previous = this;
return(null);
}
Expression[] previousExpressions = previous.GetExpressionsToTargetEntity();
Expression[] candidateExpressions = this.GetExpressionsToTargetEntity();
return(CheckCompatibleAssignments(targetType, previousExpressions, candidateExpressions));
}
/// <summary>Visits a nested member init.</summary>
/// <param name="init">Expression to visit.</param>
/// <returns>The same expression.</returns>
internal override Expression VisitMemberInit(MemberInitExpression init)
{
Expression result = init;
MemberAssignmentAnalysis previousNested = null;
foreach (var binding in init.Bindings)
{
MemberAssignment assignment = binding as MemberAssignment;
if (assignment == null)
{
continue;
}
if (!this.CheckCompatibleAssignmentExpression(assignment.Expression, init.Type, ref previousNested))
{
break;
}
}
return(result);
}
/// <summary>
/// NewExpression visit method
/// </summary>
/// <param name="nex">The NewExpression to visit</param>
/// <returns>The visited NewExpression</returns>
internal override NewExpression VisitNew(NewExpression nex)
{
if (nex.Members == null)
{
return(base.VisitNew(nex));
}
else
{
// Member init for an anonymous type.
MemberAssignmentAnalysis previousNested = null;
foreach (var arg in nex.Arguments)
{
if (!this.CheckCompatibleAssignmentExpression(arg, nex.Type, ref previousNested))
{
break;
}
}
return(nex);
}
}
/// <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));
}
}
}
}
}
/// <summary>Analyzes an assignment from a member-init expression.</summary>
/// <param name="entityInScope">Entity in scope for the lambda that's providing the parameter.</param>
/// <param name="assignmentExpression">The expression to analyze.</param>
/// <returns>The analysis results.</returns>
internal static MemberAssignmentAnalysis Analyze(Expression entityInScope, Expression assignmentExpression)
{
Debug.Assert(entityInScope != null, "entityInScope != null");
Debug.Assert(assignmentExpression != null, "assignmentExpression != null");
MemberAssignmentAnalysis result = new MemberAssignmentAnalysis(entityInScope);
result.Visit(assignmentExpression);
return result;
}
/// <summary>
/// If there is a MemberInitExpression 'new Person { ID = p.ID, Friend = new Person { ID = p.Friend.ID }}'
/// or a NewExpression 'new { ID = p.ID, Friend = new { ID = p.Friend.ID }}',
/// this method validates against the RHS of the member assigment, the expression "p.ID" for example.
/// </summary>
/// <param name="expressionToAssign">The expression to validate.</param>
/// <param name="initType">Type of the MemberInit or the New expression.</param>
/// <param name="previousNested">The outter nested initializer of the current initializer we are checking.</param>
/// <returns>true if the expression to assign is fine; false otherwise.</returns>
private bool CheckCompatibleAssigmentExpression(Expression expressionToAssign, Type initType, ref MemberAssignmentAnalysis previousNested)
{
MemberAssignmentAnalysis nested = MemberAssignmentAnalysis.Analyze(this.entity, expressionToAssign);
if (nested.MultiplePathsFound)
{
this.multiplePathsFound = true;
return false;
}
// When we're visitng a nested entity initializer, we're exactly one level above that.
Exception incompatibleException = nested.CheckCompatibleAssignments(initType, ref previousNested);
if (incompatibleException != null)
{
this.incompatibleAssignmentsException = incompatibleException;
return false;
}
if (this.pathFromEntity.Count == 0)
{
this.pathFromEntity.AddRange(nested.GetExpressionsToTargetEntity());
}
return true;
}
/// <summary>
/// Checks whether the this and a <paramref name="previous"/>
/// paths for assignments are compatible.
/// </summary>
/// <param name="targetType">Type being initialized.</param>
/// <param name="previous">Previously seen member accesses (null if this is the first).</param>
/// <returns>An exception to be thrown if assignments are not compatible; null otherwise.</returns>
/// <remarks>
/// This method does not set the IncompatibleAssignmentsException property on either
/// analysis instance.
/// </remarks>
internal Exception CheckCompatibleAssignments(Type targetType, ref MemberAssignmentAnalysis previous)
{
if (previous == null)
{
previous = this;
return null;
}
Expression[] previousExpressions = previous.GetExpressionsToTargetEntity();
Expression[] candidateExpressions = this.GetExpressionsToTargetEntity();
return CheckCompatibleAssignments(targetType, previousExpressions, candidateExpressions);
}
