/// <summary>
/// Creates new delta tree describing the new snapshot
/// </summary>
/// <param name="baseSnapshotId">Base snapshot of the change set</param>
/// <param name="newSnapshotId">New snapshot of the change set</param>
/// <returns>Delta tree nodes</returns>
private INodeProvider<Guid, object, EdgeData> CreateAppendableChangeSetTree(Guid baseSnapshotId, Guid newSnapshotId, IKeyValueStorage<Guid, object> storage, Dictionary<Guid, Guid> nodeMapping, Dictionary<Guid, NodeState> nodeStates, IsolatedChangeSet<Guid, object, EdgeData> changeSet, Hashtable reusedNodes)
{
DirectNodeProviderUnsafe<Guid, object, EdgeData> delta = new DirectNodeProviderUnsafe<Guid, object, EdgeData>(storage, storage is IForceUpdateStorage);
// Create snapshot in delta
nodeMapping.Add(baseSnapshotId, newSnapshotId);
var snapshotNode = new Node<Guid, object, EdgeData>(NodeType.Snapshot, null);
snapshotNode.Previous = baseSnapshotId;
// Link to root object
snapshotNode.AddEdge(new Edge<Guid, EdgeData>(snapshotsService.GetRootObjectId(baseSnapshotId), new EdgeData(EdgeType.RootObject, null)));
// Set node to provider
delta.SetNode(newSnapshotId, snapshotNode);
// Add all changes and parent nodes
foreach (Guid nodeId in changeSet.Nodes.EnumerateNodes())
{
AddNodeToAppendableTreeRecursive(delta, nodeId, nodeMapping, nodeStates, changeSet);
}
// Prepare list of unreferenced node IDs
Dictionary<Guid, Collection<Guid>> references = new Dictionary<Guid, Collection<Guid>>();
// Resolve edges based on mapping
foreach (Guid nodeId in delta.EnumerateNodes())
{
references.Add(nodeId, new Collection<Guid>());
}
// Resolve edges based on mapping
foreach (Guid nodeId in delta.EnumerateNodes())
{
var node = delta.GetNode(nodeId, NodeAccess.ReadWrite);
foreach (var edge in node.Edges.Values)
{
// Permanent edges should not be touched
if (!Utils.IsPermanentEdge(edge))
{
// Reroute based on node mapping
if (nodeMapping.ContainsKey(edge.ToNodeId))
{
edge.ToNodeId = nodeMapping[edge.ToNodeId];
}
else
{
if (!reusedNodes.ContainsKey(edge.ToNodeId))
{
reusedNodes.Add(edge.ToNodeId, null);
}
}
// Change edge data if it points to changed node
if (edge.Data.Data != null && edge.Data.Data is Guid)
{
if (nodeMapping.ContainsKey((Guid)edge.Data.Data))
{
edge.Data = new EdgeData(edge.Data.Semantic, nodeMapping[(Guid)edge.Data.Data]);
}
}
}
else
{
if (!reusedNodes.ContainsKey(edge.ToNodeId))
{
reusedNodes.Add(edge.ToNodeId, null);
}
}
if (references.ContainsKey(edge.ToNodeId))
{
references[edge.ToNodeId].Add(nodeId);
}
}
}
// Remove remaining unreferenced nodes
bool removed = false;
do
{
removed = false;
foreach (Guid key in delta.EnumerateNodes())
{
// There are no references to the key
if ((key!=newSnapshotId) && (references[key].Count == 0))
{
#if DEBUG
Debug.WriteLine("Removed unreferenced key " + key);
#endif
delta.Remove(key);
reusedNodes.Remove(key);
nodeStates.Remove(key);
foreach (Guid otherKey in references.Keys)
{
references[otherKey].Remove(key);
}
foreach (var mappingKey in nodeMapping.Keys)
{
if (nodeMapping[mappingKey] == key)
{
nodeMapping.Remove(mappingKey);
break;
}
}
removed = true;
break;
}
}
}
while (removed);
// Isolated provider nodes have been corrupted, perform clear
changeSet.Nodes.Clear();
changeSet.NodeStates.Clear();
return delta;
}
/// <summary>
/// Creates new delta tree describing the new snapshot
/// </summary>
/// <param name="baseSnapshotId">Base snapshot of the change set</param>
/// <param name="newSnapshotId">New snapshot of the change set</param>
/// <returns>Delta tree nodes</returns>
private INodeProvider <Guid, object, EdgeData> CreateAppendableChangeSetTree(Guid baseSnapshotId, Guid newSnapshotId, IKeyValueStorage <Guid, object> storage, Dictionary <Guid, Guid> nodeMapping, Dictionary <Guid, NodeState> nodeStates, IsolatedChangeSet <Guid, object, EdgeData> changeSet, Hashtable reusedNodes)
{
DirectNodeProviderUnsafe <Guid, object, EdgeData> delta = new DirectNodeProviderUnsafe <Guid, object, EdgeData>(storage, storage is IForceUpdateStorage);
// Create snapshot in delta
nodeMapping.Add(baseSnapshotId, newSnapshotId);
var snapshotNode = new Node <Guid, object, EdgeData>(NodeType.Snapshot, null);
snapshotNode.Previous = baseSnapshotId;
// Link to root object
snapshotNode.AddEdge(new Edge <Guid, EdgeData>(snapshotsService.GetRootObjectId(baseSnapshotId), new EdgeData(EdgeType.RootObject, null)));
// Set node to provider
delta.SetNode(newSnapshotId, snapshotNode);
// Add all changes and parent nodes
foreach (Guid nodeId in changeSet.Nodes.EnumerateNodes())
{
AddNodeToAppendableTreeRecursive(delta, nodeId, nodeMapping, nodeStates, changeSet);
}
// Prepare list of unreferenced node IDs
Dictionary <Guid, Collection <Guid> > references = new Dictionary <Guid, Collection <Guid> >();
// Resolve edges based on mapping
foreach (Guid nodeId in delta.EnumerateNodes())
{
references.Add(nodeId, new Collection <Guid>());
}
// Resolve edges based on mapping
foreach (Guid nodeId in delta.EnumerateNodes())
{
var node = delta.GetNode(nodeId, NodeAccess.ReadWrite);
foreach (var edge in node.Edges.Values)
{
// Permanent edges should not be touched
if (!Utils.IsPermanentEdge(edge))
{
// Reroute based on node mapping
if (nodeMapping.ContainsKey(edge.ToNodeId))
{
edge.ToNodeId = nodeMapping[edge.ToNodeId];
}
else
{
if (!reusedNodes.ContainsKey(edge.ToNodeId))
{
reusedNodes.Add(edge.ToNodeId, null);
}
}
// Change edge data if it points to changed node
if (edge.Data.Data != null && edge.Data.Data is Guid)
{
if (nodeMapping.ContainsKey((Guid)edge.Data.Data))
{
edge.Data = new EdgeData(edge.Data.Semantic, nodeMapping[(Guid)edge.Data.Data]);
}
}
}
else
{
if (!reusedNodes.ContainsKey(edge.ToNodeId))
{
reusedNodes.Add(edge.ToNodeId, null);
}
}
if (references.ContainsKey(edge.ToNodeId))
{
references[edge.ToNodeId].Add(nodeId);
}
}
}
// Remove remaining unreferenced nodes
bool removed = false;
do
{
removed = false;
foreach (Guid key in delta.EnumerateNodes())
{
// There are no references to the key
if ((key != newSnapshotId) && (references[key].Count == 0))
{
#if DEBUG
Debug.WriteLine("Removed unreferenced key " + key);
#endif
delta.Remove(key);
reusedNodes.Remove(key);
nodeStates.Remove(key);
foreach (Guid otherKey in references.Keys)
{
references[otherKey].Remove(key);
}
foreach (var mappingKey in nodeMapping.Keys)
{
if (nodeMapping[mappingKey] == key)
{
nodeMapping.Remove(mappingKey);
break;
}
}
removed = true;
break;
}
}
}while (removed);
// Isolated provider nodes have been corrupted, perform clear
changeSet.Nodes.Clear();
changeSet.NodeStates.Clear();
return(delta);
}
