/// <summary>Walks the subtree of this node and removes all nodes which were not marked projected.</summary>
/// <remarks>Used to remove unnecessary expanded nodes.</remarks>
internal void RemoveNonProjectedNodes()
{
for (int j = this.nodes.Count - 1; j >= 0; j--)
{
ExpandedProjectionNode expandedNode = this.nodes[j] as ExpandedProjectionNode;
// Leave non-expanded properties there as they specify projections.
if (expandedNode == null)
{
continue;
}
// If we are to project entire subtree, leave all expanded nodes in as well
// otherwise remove the expanded nodes which are not marked as projected.
if (!this.projectSubtree && !expandedNode.ProjectionFound)
{
// This removes the expandedNode from the tree (and all its children)
this.nodes.RemoveAt(j);
}
else
{
expandedNode.RemoveNonProjectedNodes();
}
}
}
/// <summary>Marks the entire subtree as projected.</summary>
/// <remarks>This is used when there were no projections specified in the query
/// to mark the entire tree as projected.</remarks>
internal void MarkSubtreeAsProjected()
{
this.projectSubtree = true;
this.projectAllImmediateProperties = false;
foreach (ProjectionNode node in this.nodes)
{
ExpandedProjectionNode expandedNode = node as ExpandedProjectionNode;
if (expandedNode != null)
{
expandedNode.MarkSubtreeAsProjected();
}
}
}
/// <summary>
/// Add the projection node with the given property name, property instance and target resource type, if required.
/// </summary>
/// <param name="propertyName">Name of the property that needs to be projected.</param>
/// <param name="property">ResourceProperty instance containing information about the property - this will be null for open properties.</param>
/// <param name="targetResourceType">ResourceType instance on which the property needs to be expanded.</param>
/// <returns>A new or an existing instance of ProjectionNode.</returns>
internal ExpandedProjectionNode AddProjectionNode(string propertyName, ResourceProperty property, ResourceType targetResourceType)
{
// find out if there exists another node with the given property name.
ProjectionNode node = this.FindNode(propertyName);
if (node == null || !ExpandedProjectionNode.ApplyPropertyToExistingNode(node, property, targetResourceType))
{
// just create a simple projection node for it
node = new ProjectionNode(propertyName, property, targetResourceType);
this.AddNode(node);
}
return(node as ExpandedProjectionNode);
}
/// <summary>
/// Whether the given property can be applied to the existing node.
/// </summary>
/// <param name="existingNode">Existing node with the same property name.</param>
/// <param name="property">ResourceProperty instance for the property refered by the new segment.</param>
/// <param name="targetResourceType">TargetResourceType for the new segment.</param>
/// <returns>true if the given property can be applied to the existing node, otherwise returns false.</returns>
/// <remarks>In case this function returns true, it might modify the TargetResourceType property of the existing node.</remarks>
private static bool ApplyPropertyToExistingNode(ProjectionNode existingNode, ResourceProperty property, ResourceType targetResourceType)
{
Debug.Assert(existingNode != null, "existingNode != null");
Debug.Assert(property == null || property.Name == existingNode.PropertyName, "property == null || property.Name == existingNode.PropertyName");
// This is just quicker way of determining if declared property belongs to different sub-trees.
// Since any given property can be declared once in a chain of derived types, if the property instances
// are not the same, we can assume that they do not belong to the same hierarchy chain.
// Even if we do not have this check, everything will just work, since we check the type assignability.
if (property != null && existingNode.Property != null && property != existingNode.Property)
{
return(false);
}
ExpandedProjectionNode expansionNode = existingNode as ExpandedProjectionNode;
// If the target resource type of the new segment is a super type, we might
// need to update the target resource type of the existing node.
// Since IsAssignableFrom returns true when they are equal, it isn't require
// to do anything, but if we do, it should still work.
if (targetResourceType.IsAssignableFrom(existingNode.TargetResourceType))
{
ExpandedProjectionNode.VerifyPropertyMismatchAndExpandSelectMismatchScenario(
existingNode,
property,
targetResourceType,
expansionNode != null);
existingNode.TargetResourceType = targetResourceType;
return(true);
}
// If the existing node is already a super type, then there is nothing to do
// other than validating the error scenarios.
if (existingNode.TargetResourceType.IsAssignableFrom(targetResourceType))
{
ExpandedProjectionNode.VerifyPropertyMismatchAndExpandSelectMismatchScenario(
existingNode,
property,
targetResourceType,
expansionNode != null);
return(true);
}
return(false);
}
/// <summary>
/// Adds a new expanded node with the given segment name, if required.
/// </summary>
/// <param name="segment">Expand segment as specified in the uri.</param>
/// <param name="childSelectExpandClause">The select expand clause for the current node from the URI Parser.</param>
/// <returns>An instance of ExpandedProjectionNode - either new or existing one.</returns>
internal ExpandedProjectionNode AddExpandedNode(ExpandSegment segment, SelectExpandClause childSelectExpandClause)
{
Debug.Assert(segment.ExpandedProperty != null, "we do not allow expands on open properties");
Debug.Assert(childSelectExpandClause != null, "childSelectExpandClause != null");
ExpandedProjectionNode childNode = (ExpandedProjectionNode)this.FindNode(segment.Name);
// Currently, since we do not have a back pointer in ResourceProperty for the declaring type,
// the same resource property instance can belong to 2 completely different types.
// Hence doing reference equality on Resource Property instance does not gaurantee that they
// refer to the same property. But if the references are not equal, they are gauranteed to be
// different. The check of reference equality is to make sure we do the expensive IsAssignableFrom
// check, only if the instances are the same, and if the IsAssignable returns true, then we are
// gauranteed that the property refers to the same property.
if (childNode != null && childNode.Property == segment.ExpandedProperty)
{
// If the given segment specifies the same property on a super type (or an ancestor),
// then we need to change the target type on the segment to the super type (or ancestor),
// otherwise we should ignore the segment.
// Since IsAssignableFrom returns true, if the instances are the same, we will update the
// target resource type to the same instance. It doesn't matter, but having another check
// for reference equality makes code less readable.
if (segment.TargetResourceType.IsAssignableFrom(childNode.TargetResourceType))
{
childNode.TargetResourceType = segment.TargetResourceType;
}
}
else
{
childNode = new ExpandedProjectionNode(
segment.Name,
segment.ExpandedProperty,
segment.TargetResourceType,
segment.Container,
segment.OrderingInfo,
segment.Filter,
null,
segment.Container.PageSize != 0 ? (int?)segment.Container.PageSize : null,
segment.MaxResultsExpected != Int32.MaxValue ? (int?)segment.MaxResultsExpected : null,
childSelectExpandClause);
this.AddNode(childNode);
}
return(childNode);
}
/// <summary>Adds a new child node to this node.</summary>
/// <param name="node">The child node to add.</param>
private void AddNode(ProjectionNode node)
{
Debug.Assert(node != null, "node != null");
Debug.Assert(
this.nodes.Count(
n => n.PropertyName == node.PropertyName &&
(n.TargetResourceType.IsAssignableFrom(node.TargetResourceType) || node.TargetResourceType.IsAssignableFrom(n.TargetResourceType))) == 0,
"make sure there is no node with the same property name in the inheritance hierarchy");
this.nodes.Add(node);
ExpandedProjectionNode expandedNode = node as ExpandedProjectionNode;
if (expandedNode != null)
{
this.hasExpandedPropertyOnDerivedType = this.hasExpandedPropertyOnDerivedType || (!ResourceType.CompareReferences(this.ResourceType, node.TargetResourceType));
}
}
/// <summary>
/// Adds a new expanded node with the given segment name, if required.
/// </summary>
/// <param name="segment">Expand segment as specified in the uri.</param>
/// <param name="childSelectExpandClause">The select expand clause for the current node from the URI Parser.</param>
/// <returns>An instance of ExpandedProjectionNode - either new or existing one.</returns>
internal ExpandedProjectionNode AddExpandedNode(ExpandSegment segment, SelectExpandClause childSelectExpandClause)
{
Debug.Assert(segment.ExpandedProperty != null, "we do not allow expands on open properties");
Debug.Assert(childSelectExpandClause != null, "childSelectExpandClause != null");
ExpandedProjectionNode childNode = (ExpandedProjectionNode)this.FindNode(segment.Name);
// Currently, since we do not have a back pointer in ResourceProperty for the declaring type,
// the same resource property instance can belong to 2 completely different types.
// Hence doing reference equality on Resource Property instance does not gaurantee that they
// refer to the same property. But if the references are not equal, they are gauranteed to be
// different. The check of reference equality is to make sure we do the expensive IsAssignableFrom
// check, only if the instances are the same, and if the IsAssignable returns true, then we are
// gauranteed that the property refers to the same property.
if (childNode != null && childNode.Property == segment.ExpandedProperty)
{
// If the given segment specifies the same property on a super type (or an ancestor),
// then we need to change the target type on the segment to the super type (or ancestor),
// otherwise we should ignore the segment.
// Since IsAssignableFrom returns true, if the instances are the same, we will update the
// target resource type to the same instance. It doesn't matter, but having another check
// for reference equality makes code less readable.
if (segment.TargetResourceType.IsAssignableFrom(childNode.TargetResourceType))
{
childNode.TargetResourceType = segment.TargetResourceType;
}
}
else
{
childNode = new ExpandedProjectionNode(
segment.Name,
segment.ExpandedProperty,
segment.TargetResourceType,
segment.Container,
segment.OrderingInfo,
segment.Filter,
null,
segment.Container.PageSize != 0 ? (int?)segment.Container.PageSize : null,
segment.MaxResultsExpected != Int32.MaxValue ? (int?)segment.MaxResultsExpected : null,
childSelectExpandClause);
this.AddNode(childNode);
}
return childNode;
}
/// <summary>
/// Applies projections from the given select/expand clause to the tree represented by the given node.
/// </summary>
/// <param name="currentNode">The expand tree to apply projections to.</param>
private void ApplyProjectionsToExpandTree(ExpandedProjectionNode currentNode)
{
// If this is the last segment in the path and it was a navigation property,
// mark it to include the entire subtree
if (currentNode.SelectExpandClause.AllSelected)
{
currentNode.ProjectionFound = true;
currentNode.MarkSubtreeAsProjected();
}
foreach (var selectItem in currentNode.SelectExpandClause.SelectedItems)
{
currentNode.ProjectionFound = true;
// '*' is special, it means "Project all immediate properties on this level."
if (selectItem is WildcardSelectItem)
{
currentNode.ProjectAllImmediateProperties = true;
continue;
}
if (selectItem is NamespaceQualifiedWildcardSelectItem)
{
currentNode.ProjectAllImmediateOperations = true;
continue;
}
ODataPath path;
var expandItem = selectItem as ExpandedNavigationSelectItem;
if (expandItem != null)
{
path = expandItem.PathToNavigationProperty;
}
else
{
var pathSelectionItem = selectItem as PathSelectItem;
Debug.Assert(pathSelectionItem != null, "Unexpeced selection item type: " + selectItem.GetType());
path = pathSelectionItem.SelectedPath;
}
ExpandedProjectionNode childNode = this.ApplyPathSelection(path, currentNode);
if (expandItem != null)
{
if (childNode == null)
{
throw DataServiceException.CreateBadRequestError(Strings.RequestQueryProcessor_ProjectedPropertyWithoutMatchingExpand(((NavigationPropertySegment)path.LastSegment).NavigationProperty.Name));
}
this.ApplyProjectionsToExpandTree(childNode);
}
}
}
/// <summary>
/// Performs a depth-first walk down the expand tree, copying and adding to the current path as it goes. When the bottom of a path is reached, the path is added to the overall set of paths.
/// </summary>
/// <param name="currentPath">The current path so far for this depth-first traversal of the tree. Starts out null.</param>
/// <param name="currentNode">The current node of the expand tree.</param>
/// <param name="rootNode">The root node of the expand tree.</param>
private void ExtractExpandPathSegmentCollections(ExpandSegmentCollection currentPath, ExpandedProjectionNode currentNode, RootProjectionNode rootNode)
{
ExpandSegmentCollection nextPath = null;
foreach (ExpandedNavigationSelectItem expandItem in currentNode.SelectExpandClause.SelectedItems.OfType<ExpandedNavigationSelectItem>())
{
rootNode.ExpansionsSpecified = true;
if (currentPath == null)
{
nextPath = new ExpandSegmentCollection();
}
else
{
// create a copy of the current path.
nextPath = new ExpandSegmentCollection(currentPath.Count);
nextPath.AddRange(currentPath);
}
var segment = this.CreateExpandSegment(expandItem, currentNode.ResourceType);
nextPath.Add(segment);
ExpandedProjectionNode childNode = currentNode.AddExpandedNode(segment, expandItem.SelectAndExpand);
// if there are any derived expansions in the tree, set the rootNode.DerivedExpansionsSpecified to true.
if (currentNode.HasExpandedPropertyOnDerivedType)
{
rootNode.ExpansionOnDerivedTypesSpecified = true;
}
this.ExtractExpandPathSegmentCollections(nextPath, childNode, rootNode);
}
if (nextPath == null && currentPath != null)
{
this.expandPaths.Add(currentPath);
}
}
/// <summary>
/// Applies the given path-based selection item to the given projection node.
/// </summary>
/// <param name="path">The path being selected.</param>
/// <param name="currentNode">The current projection node.</param>
/// <returns>A new or an existing instance of the ExpandedProjectionNode for path of the selection item.</returns>
private ExpandedProjectionNode ApplyPathSelection(ODataPath path, ExpandedProjectionNode currentNode)
{
Debug.Assert(path != null, "path != null");
ResourceType targetResourceType = this.GetTargetResourceTypeFromTypeSegments(path, currentNode.ResourceType);
Debug.Assert(targetResourceType != null, "targetResourceType != null");
ODataPathSegment lastSegment = path.LastSegment;
Debug.Assert(lastSegment != null, "lastSegment != null");
var operationSegment = lastSegment as OperationSegment;
if (operationSegment != null)
{
ApplySelectionForOperations(operationSegment, currentNode, targetResourceType);
return currentNode;
}
var openPropertySegment = lastSegment as OpenPropertySegment;
if (openPropertySegment != null)
{
return ApplyProjectionForProperty(currentNode, openPropertySegment.PropertyName, null /*property*/, targetResourceType);
}
var propertySegment = lastSegment as PropertySegment;
IEdmProperty edmProperty;
if (propertySegment == null)
{
var navigationSegment = lastSegment as NavigationPropertySegment;
Debug.Assert(navigationSegment != null, "Unexpected type of select segment: " + lastSegment.GetType());
edmProperty = navigationSegment.NavigationProperty;
}
else
{
edmProperty = propertySegment.Property;
}
ResourceProperty resourceProperty = ((IResourcePropertyBasedEdmProperty)edmProperty).ResourceProperty;
Debug.Assert(resourceProperty != null, "resourceProperty != null");
// Look for any navigation properties that are hidden (EntitySetRights set to None)
// If it is hidden, throw exception so we don't do any information disclousure
// See Information disclosure: Astoria server allows 'hidden' navigation properties to be selected
if (edmProperty.PropertyKind == EdmPropertyKind.Navigation && this.service.Provider.GetResourceSet(currentNode.ResourceSetWrapper, targetResourceType, resourceProperty) == null)
{
throw DataServiceException.CreateBadRequestError(Strings.BadRequest_InvalidPropertyNameSpecified(resourceProperty.Name, targetResourceType.FullName));
}
return ApplyProjectionForProperty(currentNode, resourceProperty.Name, resourceProperty, targetResourceType);
}
/// <summary>
/// Applies the selection for the given operation segment to the given projection node.
/// </summary>
/// <param name="operationSegment">The operation segment to apply to the projection node.</param>
/// <param name="currentNode">The current projection node.</param>
/// <param name="targetResourceType">The target type based on type segments.</param>
private static void ApplySelectionForOperations(OperationSegment operationSegment, ExpandedProjectionNode currentNode, ResourceType targetResourceType)
{
IEnumerable<OperationWrapper> selectedOperations = operationSegment.Operations.Select(f =>
{
var metadataProviderEdmFunctionImport = f as MetadataProviderEdmOperation;
Debug.Assert(metadataProviderEdmFunctionImport != null, "metadataProviderEdmFunctionImport != null");
OperationWrapper operation = metadataProviderEdmFunctionImport.ServiceOperation;
Debug.Assert(operation != null, "operation != null");
return operation;
});
// Note that AddSelectedOperations will return false if the enumerable is empty.
bool anyOperations = currentNode.SelectedOperations.AddSelectedOperations(targetResourceType, selectedOperations);
Debug.Assert(anyOperations, "Operations segment should not have been created if no operations were found.");
}
/// <summary>
/// Apply projection for the given property to the parent projection node.
/// </summary>
/// <param name="parentNode">The parent node which the new node will be added to.</param>
/// <param name="propertyName">Name of the property that needs to be projected.</param>
/// <param name="property">ResourceProperty instance containing information about the property - this will be null for open properties.</param>
/// <param name="targetResourceType">ResourceType instance on which the property needs to be expanded.</param>
/// <returns>A new or an existing instance of the ExpandedProjectionNode for the given property.</returns>
private static ExpandedProjectionNode ApplyProjectionForProperty(ExpandedProjectionNode parentNode, string propertyName, ResourceProperty property, ResourceType targetResourceType)
{
Debug.Assert(parentNode != null, "parentNode != null");
Debug.Assert(!string.IsNullOrEmpty(propertyName), "!string.IsNullOrEmpty(propertyName)");
Debug.Assert(targetResourceType != null, "targetResourceType != null");
var childNode = parentNode.AddProjectionNode(propertyName, property, targetResourceType);
Debug.Assert(
childNode == null || childNode.ResourceType == property.ResourceType,
"If we're traversing over a nav. property it's resource type must match the resource type of the expanded segment.");
return childNode;
}
/// <summary>Removes duplicates from the tree caused by wildcards and sorts the projected properties.</summary>
/// <param name="provider">underlying provider instance.</param>
/// <remarks>
/// Examples
/// $select=Orders, Orders/ID - get rid of the Orders/ID
/// $select=Orders, Orders/* - get rid of the Orders/*
/// $select=Orders/*, Orders/ID - get rid of the Orders/ID
/// $select=Orders/*, Orders/OrderItems&$expand=Orders - get rid of the Orders/OrderItems (it's redundant to *)
/// $select=Orders/*, Orders/OrderItems&$expand=Orders/OrderItems - leave as is, the Orders/OrderItems are expanded
///
/// The sorting order is the same as the order in which the properties are enumerated on the owning type.
/// This is to preserve the same order as if no projections occured.
/// </remarks>
internal void ApplyWildcardsAndSort(DataServiceProviderWrapper provider)
{
// If this segment was marked to include entire subtree
// simply remove all children which are not expanded
// and propagate the information to all expanded children.
if (this.projectSubtree)
{
for (int j = this.nodes.Count - 1; j >= 0; j--)
{
ExpandedProjectionNode expandedNode = this.nodes[j] as ExpandedProjectionNode;
if (expandedNode != null)
{
expandedNode.projectSubtree = true;
expandedNode.ApplyWildcardsAndSort(provider);
}
}
this.projectAllImmediateProperties = false;
this.projectAllImmediateOperations = false;
return;
}
for (int j = this.nodes.Count - 1; j >= 0; j--)
{
ExpandedProjectionNode expandedNode = this.nodes[j] as ExpandedProjectionNode;
// If this node was marked to include all immediate properties,
// remove all children which are not expanded.
// That means they are either simple properties or nav. properties which
// are not going to be expanded anyway.
if (this.ProjectAllImmediateProperties && expandedNode == null)
{
this.nodes.RemoveAt(j);
}
else if (expandedNode != null)
{
expandedNode.ApplyWildcardsAndSort(provider);
}
}
if (this.nodes.Count > 0)
{
// Sort the subsegments such that they have the same order as the properties
// on the owning resource type.
// build the list of existing resource types that this query touches
List <ResourceType> resourceTypes = new List <ResourceType>();
resourceTypes.Add(this.ResourceType);
// If we have one or more derived properties to expand or project,
// we need to sort it based on the order in which the derived types
// are return.
List <ProjectionNode> derivedProjectionNodes = this.nodes.Where(n => !ResourceType.CompareReferences(n.TargetResourceType, this.ResourceType)).ToList();
if (derivedProjectionNodes.Count > 0)
{
foreach (ResourceType rt in provider.GetDerivedTypes(this.ResourceType))
{
if (derivedProjectionNodes.FirstOrDefault(node => node.TargetResourceType == rt) != null)
{
resourceTypes.Add(rt);
}
}
}
#if DEBUG
int count = this.nodes.Count;
#endif
this.nodes = ExpandedProjectionNode.SortNodes(this.nodes, resourceTypes);
#if DEBUG
Debug.Assert(this.nodes.Count == count, "We didn't sort all the properties.");
#endif
}
}
