/// <summary>
/// Updates the object value from a source object of the same type.
/// </summary>
/// <param name="loader"></param>
/// <param name="source"></param>
private void UpdateFrom(ValueLoader loader, object source)
{
Version++;
// if no one is holding the value, don't bother updating.
//
if (!CheckIfAnyoneCares())
{
return;
}
int version = Version;
object value = ValueInternal;
// sure source matches dest
//
if (!value.GetType().IsInstanceOfType(source))
{
throw new InvalidOperationException("Types not compatible");
}
Action handler = () =>
{
// make sure another update hasn't beat us to the punch.
if (Version > version)
{
return;
}
try {
_stats.OnStartUpdate();
ReflectionSerializer.UpdateObject(source, value, true, LastUpdatedTime);
}
finally {
_stats.OnCompleteUpdate();
}
// notify successful completion.
NotifyCompletion(loader, null);
};
if (SynchronousMode)
{
handler();
}
else
{
PriorityQueue.AddUiWorkItem(
handler
);
}
}
private CacheEntry Get <T>(LoadContext loadContext, Action <T> completed, Action <Exception> error, bool resetCallbacks) where T : new()
{
if (loadContext == null)
{
throw new ArgumentNullException("LoadContext required.");
}
object identity = loadContext.UniqueKey;
CacheEntry value;
lock (_objectCache) {
if (_objectCache.ContainsKey(typeof(T)) && _objectCache[typeof(T)].TryGetValue(identity, out value))
{
value.LoadContext = loadContext;
if (resetCallbacks)
{
SetupCompletedCallback <T>(completed, error, value);
}
return(value);
}
}
Type objectType = typeof(T);
Action <CacheEntry> proxyCallback =
cacheEntry =>
{
var v = (T)cacheEntry.ValueInternal;
foreach (var proxy in GetProxies <T>(cacheEntry.LoadContext))
{
// copy the values over
//
ReflectionSerializer.UpdateObject(v, proxy.ProxyReference.Target, true, null);
// fire the update notification
//
if (proxy.UpdateAction != null)
{
proxy.UpdateAction();
}
}
};
// create a new one.
//
value = new CacheEntry(loadContext, objectType, proxyCallback);
value.NextCompletedAction.UnhandledError = OnUnhandledError;
object loader = GetDataLoader(value);
// How to create a new value. It's just a new.
//
value.CreateDefaultAction = () =>
{
// if there is a proxy already registered, use it as the key value.
//
var proxy = GetProxies <T>(loadContext).FirstOrDefault();
if (proxy != null && proxy.ProxyReference != null && proxy.ProxyReference.IsAlive)
{
return(proxy.ProxyReference.Target);
}
var item = new T();
if (item is ILoadContextItem)
{
((ILoadContextItem)item).LoadContext = value.LoadContext;
}
return(item);
};
SetupCompletedCallback <T>(completed, error, value);
// How to load a new value.
//
value.LoadAction = (lvl) =>
{
if (loader == null)
{
throw new InvalidOperationException("Could not find loader for type: " + typeof(T).Name);
}
// get a loader and ask for a load request.
//
Debug.Assert(loader != null, "Failed to get loader for " + typeof(T).Name);
var request = DataLoaderProxy.GetLoadRequest(loader, value.LoadContext, typeof(T));
if (request == null)
{
Debug.WriteLine("{0}: Aborting load for {1}, ID={2}, because {3}.GetLoadRequest returned null.", DateTime.Now, typeof(T).Name, value.LoadContext.Identity, loader.GetType().Name);
return(false);
}
// fire off the load.
//
IsLoading = true;
request.Execute(
(result) =>
{
if (result == null)
{
throw new ArgumentNullException("result", "Execute must return a LoadRequestResult value.");
}
if (result.Error == null)
{
lvl.OnLoadSuccess(result.Stream);
}
else
{
lvl.OnLoadFail(new LoadRequestFailedException(lvl.CacheEntry.ObjectType, value.LoadContext, result.Error));
}
IsLoading = false;
}
);
return(true);
};
// how to deserialize.
value.DeserializeAction = (id, data, isOptimized) =>
{
if (loader == null)
{
throw new InvalidOperationException("Could not find loader for type: " + typeof(T).Name);
}
// get the loader and ask for deserialization
//
object deserializedObject = null;
if (isOptimized)
{
var idl = (IDataOptimizer)loader;
if (idl == null)
{
throw new InvalidOperationException("Data is optimized but object does not implmenent IDataOptimizer");
}
deserializedObject = idl.DeserializeOptimizedData(value.LoadContext, objectType, data);
}
else
{
deserializedObject = DataLoaderProxy.Deserialize(loader, value.LoadContext, objectType, data);
}
if (deserializedObject == null)
{
throw new InvalidOperationException(String.Format("Deserialize returned null for {0}, id='{1}'", objectType.Name, id));
}
if (!objectType.IsInstanceOfType(deserializedObject))
{
throw new InvalidOperationException(String.Format("Returned object is {0} when {1} was expected", deserializedObject.GetType().Name, objectType.Name));
}
return(deserializedObject);
};
// if this thing knows how to optimize, hook that up.
//
if (loader is IDataOptimizer)
{
value.SerializeOptimizedDataAction = (obj, stream) =>
{
var idl = (IDataOptimizer)loader;
return(idl.SerializeOptimizedData(obj, stream));
};
}
// finally push the value into the cache.
lock (_objectCache) {
if (!_objectCache.ContainsKey(objectType))
{
Dictionary <object, CacheEntry> typeDictionary = new Dictionary <object, CacheEntry>();
_objectCache[typeof(T)] = typeDictionary;
}
_objectCache[typeof(T)][identity] = value;
}
return(value);
}
/// <summary>
/// Merge a list of items with the contents of this ObsColl.
///
/// IMPORTANT: This method assumes that the contents of the this list are sorted
/// in the same sort order as specified by the compare action.
///
/// If they are not, then the resulting list is likely to be wrong.
/// </summary>
/// <param name="newItems">The new list of ites</param>
/// <param name="compare">The comparison function between two items</param>
/// <param name="itemMergeBehavior">The way toi handle equivlent items.</param>
public void Merge(IList <T> newItems, Comparison <T> compare, EquivelentItemMergeBehavior itemMergeBehavior)
{
// Shortcuts for 0 items
//
if (newItems == null || newItems.Count == 0)
{
ClearItems();
return;
}
if (Count == 0)
{
AddRange(newItems);
return;
}
CancelBatch();
var sortedExisting = this; // we have to assume the list is currently sorted by the specified comparer.
// sort the newArray
var sortedNew = newItems.ToArray();
Array.Sort <T>(sortedNew, compare);
int currentPos = 0;
// Now walk each item in the new array and compare it against the current
// items in the collection.
//
foreach (var newItem in sortedNew)
{
T existingItem = default(T);
// if we're past the end of the old list,
// just start adding.
//
if (currentPos < Count)
{
existingItem = this[currentPos];
}
else
{
Add(newItem);
continue;
}
int compareResult = compare(newItem, existingItem);
if (compareResult == 0)
{
// we found the match, so just replace the item
// or do nothing.
//
bool isSameObject = Object.Equals(existingItem, newItem);
if (isSameObject)
{
switch (itemMergeBehavior)
{
case EquivelentItemMergeBehavior.ReplaceEqualItems:
this[currentPos] = newItem;
break;
case EquivelentItemMergeBehavior.UpdateEqualItems:
ReflectionSerializer.UpdateObject(newItem, existingItem, true, null);
break;
default:
break;
}
}
else
{
// TODO: WRITE TEST FOR THIS CASE
// something compared as equal, but it's a different object
// so insert the new one before the existing one.
//
this.Insert(currentPos, newItem);
}
currentPos++;
}
else if (compareResult < 0)
{
// the new item comes before the existing item, so add it.
//
this.Insert(currentPos, newItem);
currentPos++;
}
else if (compareResult > 0)
{
// the new item should come after this item,
// so just replace the current item with our new item.
//
this[currentPos] = newItem;
currentPos++;
}
}
// remove any that are left in the old list.
//
for (int i = this.Count - 1; i >= currentPos; i--)
{
this.RemoveAt(i);
}
}
