public IEnumerable<Model> RemoveBranch (Model model)
{
Node node;
if (!nodes.TryGetValue (model, out node))
return Enumerable.Empty<Model> ();
var removedModels = new List<Model> ();
// Find elders (highest parents):
var elders = new HashSet<Model> ();
var parentStack = new Stack<Model> ();
parentStack.Push (model);
while (parentStack.Count > 0) {
var parent = parentStack.Pop ();
var parentNode = nodes [parent];
if (parentNode.Parents.Count == 0) {
elders.Add (parent);
} else {
foreach (var grandparent in parentNode.Parents) {
parentStack.Push (grandparent);
}
}
}
// Remove elders from graph:
foreach (var elder in elders) {
Remove (elder, removedModels);
}
return removedModels;
}
public virtual void Merge (Model model)
{
if (model.GetType () != GetType ())
throw new ArgumentException ("Cannot merge models of different kind", "model");
lock (SyncRoot) {
MergeSimpleOverwrite (model);
}
}
public IEnumerable<Model> Remove (Model model)
{
Node node;
if (!nodes.TryGetValue (model, out node))
return Enumerable.Empty<Model> ();
var removedModels = new List<Model> ();
Remove (model, removedModels);
return removedModels;
}
public void Add (Model model, Model parent = null)
{
if (parent != null)
Add (parent);
Node node;
if (!nodes.TryGetValue (model, out node)) {
nodes [model] = node = new Node ();
}
if (parent != null) {
node.Parents.Add (parent);
nodes [parent].Children.Add (model);
}
}
private void Remove (Model model, List<Model> deleted)
{
Node node;
if (!nodes.TryGetValue (model, out node))
return;
// Remove children
foreach (var child in node.Children.ToList ()) {
Remove (child, deleted);
}
// Detach from parents
foreach (var parent in node.Parents.ToList ()) {
nodes [parent].Children.Remove (model);
}
nodes.Remove (model);
deleted.Add (model);
}
protected void MergeSimpleOverwrite (Model other)
{
if (this.IsShared && other.IsShared)
throw new InvalidOperationException ("Cannot merge two shared models.");
IsMerging = true;
try {
// Very simple merging rules: the newest one is always correct, remote deletion overrides everything.
if (other.ModifiedAt <= this.ModifiedAt && other.RemoteDeletedAt == null)
return;
// Update properties defined in subclasses:
var props =
from p in GetType ().GetProperties ()
where p.CanRead && p.CanWrite && p.DeclaringType != typeof(Model)
select p;
foreach (var prop in props) {
var val = prop.GetValue (other, null);
prop.SetValue (this, val, null);
}
// Update our own properties in a specific order:
this.RemoteId = other.RemoteId;
this.RemoteDeletedAt = other.RemoteDeletedAt;
this.RemoteRejected = other.RemoteRejected;
if (other.RemoteDeletedAt != null) {
// Custom logic for handling remote deletions:
this.IsPersisted = false;
this.DeletedAt = other.RemoteDeletedAt.Value;
} else {
if (other.IsPersisted)
this.IsPersisted = other.IsPersisted;
this.DeletedAt = other.DeletedAt;
}
this.ModifiedAt = other.ModifiedAt;
this.IsDirty = other.IsDirty;
} finally {
IsMerging = false;
}
}
public ModelChangedMessage (Model model, string property) : base (model)
{
this.propertyName = property;
}