/// <summary>
/// Visit an <see cref="InputReferenceExpression"/>, producing a new InputReferenceExpression
/// based on the visited form of the <see cref="QueryableResourceExpression"/> that is referenced by
/// the InputReferenceExpression argument, <paramref name="ire"/>.
/// </summary>
/// <param name="ire">InputReferenceExpression expression to visit</param>
/// <returns>Visited InputReferenceExpression expression</returns>
internal virtual Expression VisitInputReferenceExpression(InputReferenceExpression ire)
{
Debug.Assert(ire != null, "ire != null -- otherwise caller never should have visited here");
ResourceExpression re = (ResourceExpression)this.Visit(ire.Target);
return(re.CreateReference());
}
/// <summary>
/// Analyzes a lambda expression to check whether it can be satisfied with
/// $select and client-side materialization.
/// </summary>
/// <param name="le">Lambda expression.</param>
/// <param name="re">Resource expression in scope.</param>
/// <param name="matchMembers">Whether member accesses are matched as top-level projections.</param>
/// <param name="context">Context of expression to analyze.</param>
/// <returns>true if the lambda is a client-side projection; false otherwise.</returns>
internal static bool Analyze(LambdaExpression le, ResourceExpression re, bool matchMembers, DataServiceContext context)
{
Debug.Assert(le != null, "le != null");
if (le.Body.NodeType == ExpressionType.Constant)
{
if (ClientTypeUtil.TypeOrElementTypeIsEntity(le.Body.Type))
{
throw new NotSupportedException(Strings.ALinq_CannotCreateConstantEntity);
}
re.Projection = new ProjectionQueryOptionExpression(le.Body.Type, le, new List<string>());
return true;
}
if (le.Body.NodeType == ExpressionType.MemberInit || le.Body.NodeType == ExpressionType.New)
{
AnalyzeResourceExpression(le, re, context);
return true;
}
if (matchMembers)
{
// Members can be projected standalone or type-casted.
Expression withoutConverts = SkipConverts(le.Body);
if (withoutConverts.NodeType == ExpressionType.MemberAccess)
{
AnalyzeResourceExpression(le, re, context);
return true;
}
}
return false;
}
/// <summary>
/// Retargets this input reference to point to the resource set specified by <paramref name="newTarget"/>.
/// </summary>
/// <param name="newTarget">The <see cref="QueryableResourceExpression"/> that this input reference should use as its target</param>
internal void OverrideTarget(QueryableResourceExpression newTarget)
{
Debug.Assert(newTarget != null, "Resource set cannot be null");
Debug.Assert(newTarget.ResourceType.Equals(this.Type), "Cannot reference a resource set with a different resource type");
this.target = newTarget;
}
/// <summary>
/// Analyzes a lambda expression to check whether it can be satisfied with
/// $select and client-side materialization.
/// </summary>
/// <param name="le">Lambda expression.</param>
/// <param name="re">Resource expression in scope.</param>
/// <param name="matchMembers">Whether member accesses are matched as top-level projections.</param>
/// <param name="context">Context of expression to analyze.</param>
/// <returns>true if the lambda is a client-side projection; false otherwise.</returns>
internal static bool Analyze(LambdaExpression le, ResourceExpression re, bool matchMembers, DataServiceContext context)
{
Debug.Assert(le != null, "le != null");
if (le.Body.NodeType == ExpressionType.Constant)
{
if (ClientTypeUtil.TypeOrElementTypeIsEntity(le.Body.Type))
{
throw new NotSupportedException(Strings.ALinq_CannotCreateConstantEntity);
}
re.Projection = new ProjectionQueryOptionExpression(le.Body.Type, le, new List <string>());
return(true);
}
if (le.Body.NodeType == ExpressionType.MemberInit || le.Body.NodeType == ExpressionType.New)
{
AnalyzeResourceExpression(le, re, context);
return(true);
}
if (matchMembers)
{
// Members can be projected standalone or type-casted.
Expression withoutConverts = SkipConverts(le.Body);
if (withoutConverts.NodeType == ExpressionType.MemberAccess)
{
AnalyzeResourceExpression(le, re, context);
return(true);
}
}
return(false);
}
/// <summary>Builds the Uri for the expression passed in.</summary>
/// <param name="e">The expression to translate into a Uri</param>
/// <returns>Query components</returns>
internal QueryComponents Translate(Expression e)
{
Uri uri;
Version version;
bool addTrailingParens = false;
Dictionary <Expression, Expression> normalizerRewrites = null;
// short cut analysis if just a resource set or singleton resource.
// note - to be backwards compatible with V1, will only append trailing () for queries
// that include more then just a resource set.
if (!(e is QueryableResourceExpression))
{
normalizerRewrites = new Dictionary <Expression, Expression>(ReferenceEqualityComparer <Expression> .Instance);
e = Evaluator.PartialEval(e);
e = ExpressionNormalizer.Normalize(e, normalizerRewrites);
e = ResourceBinder.Bind(e, this.Context);
addTrailingParens = true;
}
UriWriter.Translate(this.Context, addTrailingParens, e, out uri, out version);
ResourceExpression re = e as ResourceExpression;
Type lastSegmentType = re.Projection == null ? re.ResourceType : re.Projection.Selector.Parameters[0].Type;
LambdaExpression selector = re.Projection == null ? null : re.Projection.Selector;
return(new QueryComponents(uri, version, lastSegmentType, selector, normalizerRewrites));
}
/// <summary>
/// Retargets this input reference to point to the resource set specified by <paramref name="newTarget"/>.
/// </summary>
/// <param name="newTarget">The <see cref="QueryableResourceExpression"/> that this input reference should use as its target</param>
internal void OverrideTarget(QueryableResourceExpression newTarget)
{
Debug.Assert(newTarget != null, "Resource set cannot be null");
Debug.Assert(newTarget.ResourceType.Equals(this.Type), "Cannot reference a resource set with a different resource type");
this.target = newTarget;
}
/// <summary>
/// Visit Query options for Resource
/// </summary>
/// <param name="re">Resource Expression with query options</param>
internal void VisitQueryOptions(ResourceExpression re)
{
if (re.HasQueryOptions)
{
this.uriBuilder.Append(UriHelper.QUESTIONMARK);
QueryableResourceExpression rse = re as QueryableResourceExpression;
if (rse != null)
{
IEnumerator options = rse.SequenceQueryOptions.GetEnumerator();
while (options.MoveNext())
{
Expression e = ((Expression)options.Current);
ResourceExpressionType et = (ResourceExpressionType)e.NodeType;
switch (et)
{
case ResourceExpressionType.SkipQueryOption:
this.VisitQueryOptionExpression((SkipQueryOptionExpression)e);
break;
case ResourceExpressionType.TakeQueryOption:
this.VisitQueryOptionExpression((TakeQueryOptionExpression)e);
break;
case ResourceExpressionType.OrderByQueryOption:
this.VisitQueryOptionExpression((OrderByQueryOptionExpression)e);
break;
case ResourceExpressionType.FilterQueryOption:
this.VisitQueryOptionExpression((FilterQueryOptionExpression)e);
break;
default:
Debug.Assert(false, "Unexpected expression type " + (int)et);
break;
}
}
}
if (re.ExpandPaths.Count > 0)
{
this.VisitExpandOptions(re.ExpandPaths);
}
if (re.Projection != null && re.Projection.Paths.Count > 0)
{
this.VisitProjectionPaths(re.Projection.Paths);
}
if (re.CountOption == CountOption.CountQuery)
{
this.VisitCountQueryOptions();
}
if (re.CustomQueryOptions.Count > 0)
{
this.VisitCustomQueryOptions(re.CustomQueryOptions);
}
this.AppendCachedQueryOptionsToUriBuilder();
}
}
/// <summary>
/// Analyzes the specified <paramref name="lambda"/> for selection and updates
/// <paramref name="resource"/>.
/// </summary>
/// <param name="lambda">Lambda expression to analyze.</param>
/// <param name="resource">Resource expression to update.</param>
/// <param name="context">Context of expression to analyze.</param>
private static void AnalyzeResourceExpression(LambdaExpression lambda, ResourceExpression resource, DataServiceContext context)
{
SelectExpandPathBuilder pb = new SelectExpandPathBuilder();
ProjectionAnalyzer.Analyze(lambda, pb, context);
resource.Projection = new ProjectionQueryOptionExpression(lambda.Body.Type, lambda, pb.ProjectionPaths.ToList());
resource.ExpandPaths = pb.ExpandPaths.Union(resource.ExpandPaths, StringComparer.Ordinal).ToList();
resource.RaiseUriVersion(pb.UriVersion);
}
/// <summary>
/// Replaces Lambda parameter references or transparent scope property accesses over those Lambda
/// parameter references with <see cref="InputReferenceExpression"/>s to the appropriate corresponding
/// <see cref="QueryableResourceExpression"/>s, based on the 'input' QueryableResourceExpression to which the
/// Lambda is logically applied and any enclosing transparent scope applied to that input resource.
/// </summary>
/// <param name="e">The expression to rebind</param>
/// <param name="currentInput">
/// The 'current input' resource - either the root resource or the
/// rightmost resource in the navigation chain.</param>
/// <param name="inputParameter">The Lambda parameter that represents a reference to the 'input'</param>
/// <param name="referencedInputs">A list that will be populated with the resources that were referenced by the rebound expression</param>
/// <returns>
/// The rebound version of <paramref name="e"/> where MemberExpression/ParameterExpressions that
/// represent resource references have been replaced with appropriate InputReferenceExpressions.
/// </returns>
internal static Expression Bind(Expression e, ResourceExpression currentInput, ParameterExpression inputParameter, List<ResourceExpression> referencedInputs)
{
Debug.Assert(e != null, "Expression cannot be null");
Debug.Assert(currentInput != null, "A current input resource is required");
Debug.Assert(inputParameter != null, "The input lambda parameter is required");
Debug.Assert(referencedInputs != null, "The referenced inputs list is required");
InputBinder binder = new InputBinder(currentInput, inputParameter);
Expression result = binder.Visit(e);
referencedInputs.AddRange(binder.referencedInputs);
return result;
}
/// <summary>
/// Replaces Lambda parameter references or transparent scope property accesses over those Lambda
/// parameter references with <see cref="InputReferenceExpression"/>s to the appropriate corresponding
/// <see cref="QueryableResourceExpression"/>s, based on the 'input' QueryableResourceExpression to which the
/// Lambda is logically applied and any enclosing transparent scope applied to that input resource.
/// </summary>
/// <param name="e">The expression to rebind</param>
/// <param name="currentInput">
/// The 'current input' resource - either the root resource or the
/// rightmost resource in the navigation chain.</param>
/// <param name="inputParameter">The Lambda parameter that represents a reference to the 'input'</param>
/// <param name="referencedInputs">A list that will be populated with the resources that were referenced by the rebound expression</param>
/// <returns>
/// The rebound version of <paramref name="e"/> where MemberExpression/ParameterExpressions that
/// represent resource references have been replaced with appropriate InputReferenceExpressions.
/// </returns>
internal static Expression Bind(Expression e, ResourceExpression currentInput, ParameterExpression inputParameter, List <ResourceExpression> referencedInputs)
{
Debug.Assert(e != null, "Expression cannot be null");
Debug.Assert(currentInput != null, "A current input resource is required");
Debug.Assert(inputParameter != null, "The input lambda parameter is required");
Debug.Assert(referencedInputs != null, "The referenced inputs list is required");
InputBinder binder = new InputBinder(currentInput, inputParameter);
Expression result = binder.Visit(e);
referencedInputs.AddRange(binder.referencedInputs);
return(result);
}
internal LambdaExpression Rebind(LambdaExpression lambda, ResourceExpression source)
{
this.successfulRebind = true;
this.oldLambdaParameter = lambda.Parameters[0];
this.projectionSource = source;
Expression body = this.Visit(lambda.Body);
if (this.successfulRebind)
{
Type delegateType = typeof(Func<,>).MakeGenericType(new Type[] { newLambdaParameter.Type, lambda.Body.Type });
return Expression.Lambda(delegateType, body, new ParameterExpression[] { this.newLambdaParameter });
}
else
{
throw new NotSupportedException(Strings.ALinq_CanOnlyProjectTheLeaf);
}
}
internal static LambdaExpression TryToRewrite(LambdaExpression le, ResourceExpression source)
{
Type proposedParameterType = source.ResourceType;
LambdaExpression result;
if (!ResourceBinder.PatternRules.MatchSingleArgumentLambda(le, out le) || // can only rewrite single parameter Lambdas.
ClientTypeUtil.TypeOrElementTypeIsEntity(le.Parameters[0].Type) || // only attempt to rewrite if lambda parameter is not an entity type
!(le.Parameters[0].Type.GetProperties().Any(p => p.PropertyType == proposedParameterType))) // lambda parameter must have public property that is same as proposed type.
{
result = le;
}
else
{
ProjectionRewriter rewriter = new ProjectionRewriter(proposedParameterType);
result = rewriter.Rebind(le, source);
}
return result;
}
internal LambdaExpression Rebind(LambdaExpression lambda, ResourceExpression source)
{
this.successfulRebind = true;
this.oldLambdaParameter = lambda.Parameters[0];
this.projectionSource = source;
Expression body = this.Visit(lambda.Body);
if (this.successfulRebind)
{
Type delegateType = typeof(Func <,>).MakeGenericType(new Type[] { newLambdaParameter.Type, lambda.Body.Type });
return(Expression.Lambda(delegateType, body, new ParameterExpression[] { this.newLambdaParameter }));
}
else
{
throw new NotSupportedException(Strings.ALinq_CanOnlyProjectTheLeaf);
}
}
internal static LambdaExpression TryToRewrite(LambdaExpression le, ResourceExpression source)
{
Type proposedParameterType = source.ResourceType;
LambdaExpression result;
if (!ResourceBinder.PatternRules.MatchSingleArgumentLambda(le, out le) || // can only rewrite single parameter Lambdas.
ClientTypeUtil.TypeOrElementTypeIsEntity(le.Parameters[0].Type) || // only attempt to rewrite if lambda parameter is not an entity type
!(le.Parameters[0].Type.GetProperties().Any(p => p.PropertyType == proposedParameterType))) // lambda parameter must have public property that is same as proposed type.
{
result = le;
}
else
{
ProjectionRewriter rewriter = new ProjectionRewriter(proposedParameterType);
result = rewriter.Rebind(le, source);
}
return(result);
}
/// <summary>
/// Constructs a new InputBinder based on the specified input resources, which is represented by the specified ParameterExpression.
/// </summary>
/// <param name="resource">The current input resource from which valid references must start</param>
/// <param name="setReferenceParam">The parameter that must be referenced in order to refer to the specified input resources</param>
private InputBinder(ResourceExpression resource, ParameterExpression setReferenceParam)
{
this.input = resource;
this.inputResource = resource as QueryableResourceExpression;
this.inputParameter = setReferenceParam;
}
/// <summary>
/// Resolves member accesses that represent transparent scope property accesses to the corresponding resource,
/// iff the input resource is enclosed in a transparent scope and the specified MemberExpression represents
/// such a property access.
/// </summary>
/// <param name="m">MemberExpression expression to visit</param>
/// <returns>
/// An InputReferenceExpression if the member access represents a transparent scope property
/// access that can be resolved to a resource in the path that produces the input resource;
/// otherwise the same MemberExpression is returned.
/// </returns>
internal override Expression VisitMemberAccess(MemberExpression m)
{
// If the current input resource is not enclosed in a transparent scope, then this
// MemberExpression cannot represent a valid transparent scope access based on the input parameter.
if (this.inputResource == null ||
!this.inputResource.HasTransparentScope)
{
return(base.VisitMemberAccess(m));
}
ParameterExpression innerParamRef = null;
Stack <PropertyInfo> nestedAccesses = new Stack <PropertyInfo>();
MemberExpression memberRef = m;
while (memberRef != null &&
PlatformHelper.IsProperty(memberRef.Member) &&
memberRef.Expression != null)
{
nestedAccesses.Push((PropertyInfo)memberRef.Member);
if (memberRef.Expression.NodeType == ExpressionType.Parameter)
{
innerParamRef = (ParameterExpression)memberRef.Expression;
}
memberRef = memberRef.Expression as MemberExpression;
}
// Only continue if the inner non-MemberExpression is the input reference ParameterExpression and
// at least one property reference is present - otherwise this cannot be a transparent scope access.
if (innerParamRef != this.inputParameter || nestedAccesses.Count == 0)
{
return(m);
}
ResourceExpression target = this.input;
QueryableResourceExpression targetResource = this.inputResource;
bool transparentScopeTraversed = false;
// Process all the traversals through transparent scopes.
while (nestedAccesses.Count > 0)
{
if (targetResource == null || !targetResource.HasTransparentScope)
{
break;
}
// Peek the property; pop it once it's consumed
// (it could be a non-transparent-identifier access).
PropertyInfo currentProp = nestedAccesses.Peek();
// If this is the accessor for the target, then the member
// refers to the target itself.
if (currentProp.Name.Equals(targetResource.TransparentScope.Accessor, StringComparison.Ordinal))
{
target = targetResource;
nestedAccesses.Pop();
transparentScopeTraversed = true;
continue;
}
// This member could also be one of the in-scope sources of the target.
Expression source;
if (!targetResource.TransparentScope.SourceAccessors.TryGetValue(currentProp.Name, out source))
{
break;
}
transparentScopeTraversed = true;
nestedAccesses.Pop();
Debug.Assert(source != null, "source != null -- otherwise ResourceBinder created an accessor to nowhere");
InputReferenceExpression sourceReference = source as InputReferenceExpression;
if (sourceReference == null)
{
targetResource = source as QueryableResourceExpression;
if (targetResource == null || !targetResource.HasTransparentScope)
{
target = (ResourceExpression)source;
}
}
else
{
targetResource = sourceReference.Target as QueryableResourceExpression;
target = targetResource;
}
}
// If no traversals were made, the original expression is OK.
if (!transparentScopeTraversed)
{
return(m);
}
// Process traversals after the transparent scope.
Expression result = this.CreateReference(target);
while (nestedAccesses.Count > 0)
{
result = Expression.Property(result, nestedAccesses.Pop());
}
return(result);
}
/// <summary>
/// Returns an <see cref="InputReferenceExpression"/> that references the specified resource,
/// and also adds the the resource to the hashset of resources that were referenced by the
/// expression that is being rebound.
/// </summary>
/// <param name="resource">The resource for which a reference was found</param>
/// <returns>An InputReferenceExpression that represents a reference to the specified resource</returns>
private Expression CreateReference(ResourceExpression resource)
{
this.referencedInputs.Add(resource);
return(resource.CreateReference());
}
/// <summary>
/// Visit Query options for Resource
/// </summary>
/// <param name="re">Resource Expression with query options</param>
internal void VisitQueryOptions(ResourceExpression re)
{
if (re.HasQueryOptions)
{
this.uriBuilder.Append(UriHelper.QUESTIONMARK);
QueryableResourceExpression rse = re as QueryableResourceExpression;
if (rse != null)
{
IEnumerator options = rse.SequenceQueryOptions.GetEnumerator();
while (options.MoveNext())
{
Expression e = ((Expression)options.Current);
ResourceExpressionType et = (ResourceExpressionType)e.NodeType;
switch (et)
{
case ResourceExpressionType.SkipQueryOption:
this.VisitQueryOptionExpression((SkipQueryOptionExpression)e);
break;
case ResourceExpressionType.TakeQueryOption:
this.VisitQueryOptionExpression((TakeQueryOptionExpression)e);
break;
case ResourceExpressionType.OrderByQueryOption:
this.VisitQueryOptionExpression((OrderByQueryOptionExpression)e);
break;
case ResourceExpressionType.FilterQueryOption:
this.VisitQueryOptionExpression((FilterQueryOptionExpression)e);
break;
default:
Debug.Assert(false, "Unexpected expression type " + (int)et);
break;
}
}
}
if (re.ExpandPaths.Count > 0)
{
this.VisitExpandOptions(re.ExpandPaths);
}
if (re.Projection != null && re.Projection.Paths.Count > 0)
{
this.VisitProjectionPaths(re.Projection.Paths);
}
if (re.CountOption == CountOption.CountQuery)
{
this.VisitCountQueryOptions();
}
if (re.CustomQueryOptions.Count > 0)
{
this.VisitCustomQueryOptions(re.CustomQueryOptions);
}
this.AppendCachedQueryOptionsToUriBuilder();
}
}
/// <summary>
/// Constructs a new InputBinder based on the specified input resources, which is represented by the specified ParameterExpression.
/// </summary>
/// <param name="resource">The current input resource from which valid references must start</param>
/// <param name="setReferenceParam">The parameter that must be referenced in order to refer to the specified input resources</param>
private InputBinder(ResourceExpression resource, ParameterExpression setReferenceParam)
{
this.input = resource;
this.inputResource = resource as QueryableResourceExpression;
this.inputParameter = setReferenceParam;
}
/// <summary>
/// Constructs a new input reference expression that refers to the specified resource set
/// </summary>
/// <param name="target">The target resource set that the new expression will reference</param>
internal InputReferenceExpression(ResourceExpression target)
{
Debug.Assert(target != null, "Target resource set cannot be null");
this.target = target;
}
/// <summary>
/// Returns an <see cref="InputReferenceExpression"/> that references the specified resource,
/// and also adds the the resource to the hashset of resources that were referenced by the
/// expression that is being rebound.
/// </summary>
/// <param name="resource">The resource for which a reference was found</param>
/// <returns>An InputReferenceExpression that represents a reference to the specified resource</returns>
private Expression CreateReference(ResourceExpression resource)
{
this.referencedInputs.Add(resource);
return resource.CreateReference();
}
/// <summary>
/// Constructs a new input reference expression that refers to the specified resource set
/// </summary>
/// <param name="target">The target resource set that the new expression will reference</param>
internal InputReferenceExpression(ResourceExpression target)
{
Debug.Assert(target != null, "Target resource set cannot be null");
this.target = target;
}
/// <summary>
/// Analyzes the specified <paramref name="lambda"/> for selection and updates
/// <paramref name="resource"/>.
/// </summary>
/// <param name="lambda">Lambda expression to analyze.</param>
/// <param name="resource">Resource expression to update.</param>
/// <param name="context">Context of expression to analyze.</param>
private static void AnalyzeResourceExpression(LambdaExpression lambda, ResourceExpression resource, DataServiceContext context)
{
SelectExpandPathBuilder pb = new SelectExpandPathBuilder();
ProjectionAnalyzer.Analyze(lambda, pb, context);
resource.Projection = new ProjectionQueryOptionExpression(lambda.Body.Type, lambda, pb.ProjectionPaths.ToList());
resource.ExpandPaths = pb.ExpandPaths.Union(resource.ExpandPaths, StringComparer.Ordinal).ToList();
resource.RaiseUriVersion(pb.UriVersion);
}
