//Copyright 2010 Microsoft Corporation
//
//Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
//You may obtain a copy of the License at
//
//http://www.apache.org/licenses/LICENSE-2.0
//
//Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
//"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//See the License for the specific language governing permissions and limitations under the License.
namespace System.Data.Services.Client{
#region Namespaces
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Diagnostics;
using System.Linq;
using System.Reflection;
#endregion
internal sealed class BindingObserver
{
#region Fields
private BindingGraph bindingGraph;
#endregion
#region Constructor
internal BindingObserver(DataServiceContext context, Func<EntityChangedParams, bool> entityChanged, Func<EntityCollectionChangedParams, bool> collectionChanged)
{
Debug.Assert(context != null, "Must have been validated during DataServiceCollection construction.");
this.Context = context;
this.Context.ChangesSaved += this.OnChangesSaved;
this.EntityChanged = entityChanged;
this.CollectionChanged = collectionChanged;
this.bindingGraph = new BindingGraph(this);
}
#endregion
#region Properties
internal DataServiceContext Context
{
get;
private set;
}
internal bool AttachBehavior
{
get;
set;
}
internal bool DetachBehavior
{
get;
set;
}
internal Func<EntityChangedParams, bool> EntityChanged
{
get;
private set;
}
internal Func<EntityCollectionChangedParams, bool> CollectionChanged
{
get;
private set;
}
#endregion
#region Methods
internal void StartTracking<T>(DataServiceCollection<T> collection, string collectionEntitySet)
{
Debug.Assert(collection != null, "Only constructed collections are tracked.");
if (!BindingEntityInfo.IsEntityType(typeof(T)))
{
throw new ArgumentException(Strings.DataBinding_DataServiceCollectionArgumentMustHaveEntityType(typeof(T)));
}
try
{
this.AttachBehavior = true;
this.bindingGraph.AddCollection(null, null, collection, collectionEntitySet);
}
finally
{
this.AttachBehavior = false;
}
}
internal void StopTracking()
{
this.bindingGraph.Reset();
this.Context.ChangesSaved -= this.OnChangesSaved;
}
#if ASTORIA_LIGHT
internal bool LookupParent<T>(DataServiceCollection<T> collection, out object parentEntity, out string parentProperty)
{
string sourceEntitySet;
string targetEntitySet;
this.bindingGraph.GetEntityCollectionInfo(collection, out parentEntity, out parentProperty, out sourceEntitySet, out targetEntitySet);
return parentEntity != null;
}
#endif
internal void OnPropertyChanged(object source, PropertyChangedEventArgs eventArgs)
{
Util.CheckArgumentNull(source, "source");
Util.CheckArgumentNull(eventArgs, "eventArgs");
#if DEBUG
Debug.Assert(this.bindingGraph.IsTracking(source), "Entity must be part of the graph if it has the event notification registered.");
#endif
string sourceProperty = eventArgs.PropertyName;
if (String.IsNullOrEmpty(sourceProperty))
{
this.HandleUpdateEntity(
source,
null,
null);
}
else
{
BindingEntityInfo.BindingPropertyInfo bpi;
object sourcePropertyValue = BindingEntityInfo.GetPropertyValue(source, sourceProperty, out bpi);
if (bpi != null)
{
this.bindingGraph.RemoveRelation(source, sourceProperty);
switch (bpi.PropertyKind)
{
case BindingPropertyKind.BindingPropertyKindCollection:
if (sourcePropertyValue != null)
{
try
{
typeof(BindingUtils)
.GetMethod("VerifyObserverNotPresent", BindingFlags.NonPublic | BindingFlags.Static)
.MakeGenericMethod(bpi.PropertyInfo.CollectionType)
.Invoke(null, new object[] { sourcePropertyValue, sourceProperty, source.GetType() });
}
catch (TargetInvocationException tie)
{
throw tie.InnerException;
}
try
{
this.AttachBehavior = true;
this.bindingGraph.AddCollection(
source,
sourceProperty,
sourcePropertyValue,
null);
}
finally
{
this.AttachBehavior = false;
}
}
break;
case BindingPropertyKind.BindingPropertyKindEntity:
this.bindingGraph.AddEntity(
source,
sourceProperty,
sourcePropertyValue,
null,
source);
break;
default:
Debug.Assert(bpi.PropertyKind == BindingPropertyKind.BindingPropertyKindComplex, "Must be complex type if PropertyKind is not entity or collection.");
if (sourcePropertyValue != null)
{
this.bindingGraph.AddComplexProperty(
source,
sourceProperty,
sourcePropertyValue);
}
this.HandleUpdateEntity(
source,
sourceProperty,
sourcePropertyValue);
break;
}
}
else
{
this.HandleUpdateEntity(
source,
sourceProperty,
sourcePropertyValue);
}
}
}
internal void OnCollectionChanged(object collection, NotifyCollectionChangedEventArgs eventArgs)
{
Util.CheckArgumentNull(collection, "collection");
Util.CheckArgumentNull(eventArgs, "eventArgs");
Debug.Assert(BindingEntityInfo.IsDataServiceCollection(collection.GetType()), "We only register this event for DataServiceCollections.");
#if DEBUG
Debug.Assert(this.bindingGraph.IsTracking(collection), "Collection must be part of the graph if it has the event notification registered.");
#endif
object source;
string sourceProperty;
string sourceEntitySet;
string targetEntitySet;
this.bindingGraph.GetEntityCollectionInfo(
collection,
out source,
out sourceProperty,
out sourceEntitySet,
out targetEntitySet);
switch (eventArgs.Action)
{
case NotifyCollectionChangedAction.Add:
this.OnAddToCollection(
eventArgs,
source,
sourceProperty,
targetEntitySet,
collection);
break;
case NotifyCollectionChangedAction.Remove:
this.OnDeleteFromCollection(
eventArgs,
source,
sourceProperty,
collection);
break;
case NotifyCollectionChangedAction.Replace:
this.OnDeleteFromCollection(
eventArgs,
source,
sourceProperty,
collection);
this.OnAddToCollection(
eventArgs,
source,
sourceProperty,
targetEntitySet,
collection);
break;
case NotifyCollectionChangedAction.Reset:
if (this.DetachBehavior)
{
this.RemoveWithDetachCollection(collection);
}
else
{
this.bindingGraph.RemoveCollection(collection);
}
break;
#if !ASTORIA_LIGHT
case NotifyCollectionChangedAction.Move:
break;
#endif
default:
throw new InvalidOperationException(Strings.DataBinding_CollectionChangedUnknownAction(eventArgs.Action));
}
}
internal void HandleAddEntity(
object source,
string sourceProperty,
string sourceEntitySet,
ICollection collection,
object target,
string targetEntitySet)
{
if (this.Context.ApplyingChanges)
{
return;
}
Debug.Assert(
(source == null && sourceProperty == null) || (source != null && !String.IsNullOrEmpty(sourceProperty)),
"source and sourceProperty should either both be present or both be absent.");
Debug.Assert(target != null, "target must be provided by the caller.");
Debug.Assert(BindingEntityInfo.IsEntityType(target.GetType()), "target must be an entity type.");
if (source != null && this.IsDetachedOrDeletedFromContext(source))
{
return;
}
EntityDescriptor targetDescriptor = this.Context.GetEntityDescriptor(target);
bool contextOperationRequired = !this.AttachBehavior &&
(targetDescriptor == null ||
(source != null && !this.IsContextTrackingLink(source, sourceProperty, target) && targetDescriptor.State != EntityStates.Deleted));
if (contextOperationRequired)
{
if (this.CollectionChanged != null)
{
EntityCollectionChangedParams args = new EntityCollectionChangedParams(
this.Context,
source,
sourceProperty,
sourceEntitySet,
collection,
target,
targetEntitySet,
NotifyCollectionChangedAction.Add);
if (this.CollectionChanged(args))
{
return;
}
}
}
if (source != null && this.IsDetachedOrDeletedFromContext(source))
{
throw new InvalidOperationException(Strings.DataBinding_BindingOperation_DetachedSource);
}
targetDescriptor = this.Context.GetEntityDescriptor(target);
if (source != null)
{
if (this.AttachBehavior)
{
if (targetDescriptor == null)
{
BindingUtils.ValidateEntitySetName(targetEntitySet, target);
this.Context.AttachTo(targetEntitySet, target);
this.Context.AttachLink(source, sourceProperty, target);
}
else
if (targetDescriptor.State != EntityStates.Deleted && !this.IsContextTrackingLink(source, sourceProperty, target))
{
this.Context.AttachLink(source, sourceProperty, target);
}
}
else
{
if (targetDescriptor == null)
{
this.Context.AddRelatedObject(source, sourceProperty, target);
}
else
if (targetDescriptor.State != EntityStates.Deleted && !this.IsContextTrackingLink(source, sourceProperty, target))
{
this.Context.AddLink(source, sourceProperty, target);
}
}
}
else
if (targetDescriptor == null)
{
BindingUtils.ValidateEntitySetName(targetEntitySet, target);
if (this.AttachBehavior)
{
this.Context.AttachTo(targetEntitySet, target);
}
else
{
this.Context.AddObject(targetEntitySet, target);
}
}
}
internal void HandleDeleteEntity(
object source,
string sourceProperty,
string sourceEntitySet,
ICollection collection,
object target,
string targetEntitySet)
{
if (this.Context.ApplyingChanges)
{
return;
}
Debug.Assert(
(source == null && sourceProperty == null) || (source != null && !String.IsNullOrEmpty(sourceProperty)),
"source and sourceProperty should either both be present or both be absent.");
Debug.Assert(target != null, "target must be provided by the caller.");
Debug.Assert(BindingEntityInfo.IsEntityType(target.GetType()), "target must be an entity type.");
Debug.Assert(!this.AttachBehavior, "AttachBehavior is only allowed during Construction and Load when this method should never be entered.");
if (source != null && this.IsDetachedOrDeletedFromContext(source))
{
return;
}
bool contextOperationRequired = this.IsContextTrackingEntity(target) && !this.DetachBehavior;
if (contextOperationRequired)
{
if (this.CollectionChanged != null)
{
EntityCollectionChangedParams args = new EntityCollectionChangedParams(
this.Context,
source,
sourceProperty,
sourceEntitySet,
collection,
target,
targetEntitySet,
NotifyCollectionChangedAction.Remove);
if (this.CollectionChanged(args))
{
return;
}
}
}
if (source != null && !this.IsContextTrackingEntity(source))
{
throw new InvalidOperationException(Strings.DataBinding_BindingOperation_DetachedSource);
}
if (this.IsContextTrackingEntity(target))
{
if (this.DetachBehavior)
{
this.Context.Detach(target);
}
else
{
this.Context.DeleteObject(target);
}
}
}
internal void HandleUpdateEntityReference(
object source,
string sourceProperty,
string sourceEntitySet,
object target,
string targetEntitySet)
{
if (this.Context.ApplyingChanges)
{
return;
}
Debug.Assert(source != null, "source can not be null for update operations.");
Debug.Assert(BindingEntityInfo.IsEntityType(source.GetType()), "source must be an entity with keys.");
Debug.Assert(!String.IsNullOrEmpty(sourceProperty), "sourceProperty must be a non-empty string for update operations.");
Debug.Assert(!String.IsNullOrEmpty(sourceEntitySet), "sourceEntitySet must be non-empty string for update operation.");
if (this.IsDetachedOrDeletedFromContext(source))
{
return;
}
EntityDescriptor targetDescriptor = target != null ? this.Context.GetEntityDescriptor(target) : null;
bool contextOperationRequired = !this.AttachBehavior &&
(targetDescriptor == null ||
!this.IsContextTrackingLink(source, sourceProperty, target));
if (contextOperationRequired)
{
if (this.EntityChanged != null)
{
EntityChangedParams args = new EntityChangedParams(
this.Context,
source,
sourceProperty,
target,
sourceEntitySet,
targetEntitySet);
if (this.EntityChanged(args))
{
return;
}
}
}
if (this.IsDetachedOrDeletedFromContext(source))
{
throw new InvalidOperationException(Strings.DataBinding_BindingOperation_DetachedSource);
}
targetDescriptor = target != null ? this.Context.GetEntityDescriptor(target) : null;
if (target != null)
{
if (targetDescriptor == null)
{
BindingUtils.ValidateEntitySetName(targetEntitySet, target);
if (this.AttachBehavior)
{
this.Context.AttachTo(targetEntitySet, target);
}
else
{
this.Context.AddObject(targetEntitySet, target);
}
targetDescriptor = this.Context.GetEntityDescriptor(target);
}
if (!this.IsContextTrackingLink(source, sourceProperty, target))
{
if (this.AttachBehavior)
{
if (targetDescriptor.State != EntityStates.Deleted)
{
this.Context.AttachLink(source, sourceProperty, target);
}
}
else
{
this.Context.SetLink(source, sourceProperty, target);
}
}
}
else
{
Debug.Assert(!this.AttachBehavior, "During attach operations we must never perform operations for null values.");
this.Context.SetLink(source, sourceProperty, null);
}
}
internal bool IsContextTrackingEntity(object entity)
{
Debug.Assert(entity != null, "entity must be provided when checking for context tracking.");
return this.Context.GetEntityDescriptor(entity) != default(EntityDescriptor);
}
private void HandleUpdateEntity(object entity, string propertyName, object propertyValue)
{
Debug.Assert(!this.AttachBehavior || this.Context.ApplyingChanges, "Entity updates must not happen during Attach or construction phases, deserialization case is the exception.");
if (this.Context.ApplyingChanges)
{
return;
}
if (!BindingEntityInfo.IsEntityType(entity.GetType()))
{
this.bindingGraph.GetAncestorEntityForComplexProperty(ref entity, ref propertyName, ref propertyValue);
}
Debug.Assert(entity != null, "entity must be provided for update operations.");
Debug.Assert(BindingEntityInfo.IsEntityType(entity.GetType()), "entity must be an entity with keys.");
Debug.Assert(!String.IsNullOrEmpty(propertyName) || propertyValue == null, "When propertyName is null no propertyValue should be provided.");
if (this.IsDetachedOrDeletedFromContext(entity))
{
return;
}
if (this.EntityChanged != null)
{
EntityChangedParams args = new EntityChangedParams(
this.Context,
entity,
propertyName,
propertyValue,
null,
null);
if (this.EntityChanged(args))
{
return;
}
}
if (this.IsContextTrackingEntity(entity))
{
this.Context.UpdateObject(entity);
}
}
private void OnAddToCollection(
NotifyCollectionChangedEventArgs eventArgs,
object source,
String sourceProperty,
String targetEntitySet,
object collection)
{
Debug.Assert(collection != null, "Must have a valid collection to which entities are added.");
if (eventArgs.NewItems != null)
{
foreach (object target in eventArgs.NewItems)
{
if (target == null)
{
throw new InvalidOperationException(Strings.DataBinding_BindingOperation_ArrayItemNull("Add"));
}
if (!BindingEntityInfo.IsEntityType(target.GetType()))
{
throw new InvalidOperationException(Strings.DataBinding_BindingOperation_ArrayItemNotEntity("Add"));
}
this.bindingGraph.AddEntity(
source,
sourceProperty,
target,
targetEntitySet,
collection);
}
}
}
private void OnDeleteFromCollection(
NotifyCollectionChangedEventArgs eventArgs,
object source,
String sourceProperty,
object collection)
{
Debug.Assert(collection != null, "Must have a valid collection from which entities are removed.");
Debug.Assert(
(source == null && sourceProperty == null) || (source != null && !String.IsNullOrEmpty(sourceProperty)),
"source and sourceProperty must both be null or both be non-null.");
if (eventArgs.OldItems != null)
{
this.DeepRemoveCollection(
eventArgs.OldItems,
source ?? collection,
sourceProperty,
this.ValidateCollectionItem);
}
}
private void RemoveWithDetachCollection(object collection)
{
Debug.Assert(this.DetachBehavior, "Must be detaching each item in collection.");
object source = null;
string sourceProperty = null;
string sourceEntitySet = null;
string targetEntitySet = null;
this.bindingGraph.GetEntityCollectionInfo(
collection,
out source,
out sourceProperty,
out sourceEntitySet,
out targetEntitySet);
this.DeepRemoveCollection(
this.bindingGraph.GetCollectionItems(collection),
source ?? collection,
sourceProperty,
null);
}
private void DeepRemoveCollection(IEnumerable collection, object source, string sourceProperty, Action<object> itemValidator)
{
foreach (object target in collection)
{
if (itemValidator != null)
{
itemValidator(target);
}
List<UnTrackingInfo> untrackingInfo = new List<UnTrackingInfo>();
this.CollectUnTrackingInfo(
target,
source,
sourceProperty,
untrackingInfo);
foreach (UnTrackingInfo info in untrackingInfo)
{
this.bindingGraph.Remove(
info.Entity,
info.Parent,
info.ParentProperty);
}
}
this.bindingGraph.RemoveUnreachableVertices();
}
private void OnChangesSaved(object sender, SaveChangesEventArgs eventArgs)
{
this.bindingGraph.RemoveNonTrackedEntities();
}
private void CollectUnTrackingInfo(
object currentEntity,
object parentEntity,
string parentProperty,
IList<UnTrackingInfo> entitiesToUnTrack)
{
foreach (var ed in this.Context
.Entities
.Where(x => x.ParentEntity == currentEntity && x.State == EntityStates.Added))
{
this.CollectUnTrackingInfo(
ed.Entity,
ed.ParentEntity,
ed.ParentPropertyForInsert,
entitiesToUnTrack);
}
entitiesToUnTrack.Add(new UnTrackingInfo
{
Entity = currentEntity,
Parent = parentEntity,
ParentProperty = parentProperty
});
}
private bool IsContextTrackingLink(object source, string sourceProperty, object target)
{
Debug.Assert(source != null, "source entity must be provided.");
Debug.Assert(BindingEntityInfo.IsEntityType(source.GetType()), "source must be an entity with keys.");
Debug.Assert(!String.IsNullOrEmpty(sourceProperty), "sourceProperty must be provided.");
Debug.Assert(target != null, "target entity must be provided.");
Debug.Assert(BindingEntityInfo.IsEntityType(target.GetType()), "target must be an entity with keys.");
return this.Context.GetLinkDescriptor(source, sourceProperty, target) != default(LinkDescriptor);
}
private bool IsDetachedOrDeletedFromContext(object entity)
{
Debug.Assert(entity != null, "entity must be provided.");
Debug.Assert(BindingEntityInfo.IsEntityType(entity.GetType()), "entity must be an entity with keys.");
EntityDescriptor descriptor = this.Context.GetEntityDescriptor(entity);
return descriptor == null || descriptor.State == EntityStates.Deleted;
}
private void ValidateCollectionItem(object target)
{
if (target == null)
{
throw new InvalidOperationException(Strings.DataBinding_BindingOperation_ArrayItemNull("Remove"));
}
if (!BindingEntityInfo.IsEntityType(target.GetType()))
{
throw new InvalidOperationException(Strings.DataBinding_BindingOperation_ArrayItemNotEntity("Remove"));
}
}
#endregion
private class UnTrackingInfo
{
public object Entity
{
get;
set;
}
public object Parent
{
get;
set;
}
public string ParentProperty
{
get;
set;
}
}
}
}
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