/// <summary>
/// Creates an instance of <see cref="ExpandSegment"/> based on the metadata in the given <see cref="ExpandedNavigationSelectItem"/>.
/// </summary>
/// <param name="expandItem">The metadata-bound expand segment to create the <see cref="ExpandSegment"/> from.</param>
/// <param name="currentResourceType">The current resource type.</param>
/// <returns>The created <see cref="ExpandSegment"/>.</returns>
private ExpandSegment CreateExpandSegment(ExpandedNavigationSelectItem expandItem, ResourceType currentResourceType)
{
Debug.Assert(expandItem != null, "expandItem != null");
Debug.Assert(currentResourceType != null, "currentResourceType != null");
// pull the Resource* instances from annotations on the IEdm* instances.
IEdmNavigationProperty navigationProperty = ((NavigationPropertySegment)expandItem.PathToNavigationProperty.LastSegment).NavigationProperty;
ResourceProperty property = ((IResourcePropertyBasedEdmProperty)navigationProperty).ResourceProperty;
Debug.Assert(property != null, "property != null");
ResourceSetWrapper targetResourceSet = ((IResourceSetBasedEdmEntitySet)expandItem.NavigationSource).ResourceSet;
Debug.Assert(targetResourceSet != null, "targetResourceSet != null");
// Further scope the type based on type segments in the path.
currentResourceType = this.GetTargetResourceTypeFromTypeSegments(expandItem.PathToNavigationProperty, currentResourceType);
Debug.Assert(currentResourceType != null, "currentResourceType != null");
// The expanded resource type may require higher response version. Update version of the response accordingly
//
// Note the response DSV is payload specific and since for GET we won't know what DSV the instances to be
// serialized will require until serialization time which happens after the headers are written,
// the best we can do is to determine this at the set level.
this.description.UpdateVersion(targetResourceSet, this.service);
bool singleResult = property.Kind == ResourcePropertyKind.ResourceReference;
DataServiceConfiguration.CheckResourceRightsForRead(targetResourceSet, singleResult);
Expression filter = DataServiceConfiguration.ComposeQueryInterceptors(this.service.Instance, targetResourceSet);
if (targetResourceSet.PageSize != 0 && !singleResult && !this.IsCustomPaged)
{
OrderingInfo internalOrderingInfo = new OrderingInfo(true);
ParameterExpression p = Expression.Parameter(targetResourceSet.ResourceType.InstanceType, "p");
foreach (var keyProp in targetResourceSet.GetKeyPropertiesForOrderBy())
{
Expression e;
if (keyProp.CanReflectOnInstanceTypeProperty)
{
e = Expression.Property(p, targetResourceSet.ResourceType.GetPropertyInfo(keyProp));
}
else
{
// object LateBoundMethods.GetValue(object, ResourceProperty)
e = Expression.Call(
null, /*instance*/
DataServiceProviderMethods.GetValueMethodInfo,
p,
Expression.Constant(keyProp));
e = Expression.Convert(e, keyProp.Type);
}
internalOrderingInfo.Add(new OrderingExpression(Expression.Lambda(e, p), true));
}
return new ExpandSegment(property.Name, filter, targetResourceSet.PageSize, targetResourceSet, currentResourceType, property, internalOrderingInfo);
}
if (!singleResult && this.IsCustomPaged)
{
// Expansion of collection could result in custom paging provider giving next link, so we need to set the null continuation token.
this.CheckAndApplyCustomPaging(null);
}
return new ExpandSegment(property.Name, filter, this.service.Configuration.MaxResultsPerCollection, targetResourceSet, currentResourceType, property, null);
}
/// <summary>
/// Updates the topLevelOrderingInfo member with the new collection of expressions that
/// dereference the ExpandedElement property on the top level wrapper object
/// </summary>
/// <param name="resultWrapperType">Type of top level wrapper object</param>
private void UpdateOrderingInfoWithSkipTokenWrapper(Type resultWrapperType)
{
OrderingInfo newOrderingInfo = new OrderingInfo(true);
ParameterExpression wrapperParameter = Expression.Parameter(resultWrapperType, "w");
foreach (var ordering in this.topLevelOrderingInfo.OrderingExpressions)
{
LambdaExpression oldExpression = (LambdaExpression)ordering.Expression;
Expression newOrdering = ParameterReplacerVisitor.Replace(
oldExpression.Body,
oldExpression.Parameters[0],
Expression.MakeMemberAccess(wrapperParameter, resultWrapperType.GetProperty("ExpandedElement")));
newOrderingInfo.Add(new OrderingExpression(Expression.Lambda(newOrdering, wrapperParameter), ordering.IsAscending));
}
this.topLevelOrderingInfo = newOrderingInfo;
}