protected virtual void OnMerge(MergeableNode <T> existingNode, MergeableNode <T> node)
{
// Process children.
if (node.Children != null && node.Children.Count > 0)
{
EnsureChildren(existingNode);
Merge(existingNode.Children, node.Children);
}
}
private static void EnsureChildren(MergeableNode <T> node)
{
Debug.Assert(node != null);
if (node.Children == null)
{
node.Children = new MergeableNodeCollection <T>();
}
}
public MergeableNode <T> GetRoot()
{
MergeableNode <T> node = this;
while (node.Parent != null)
{
node = node.Parent;
}
return(node);
}
protected virtual void OnInsert(MergeableNodeCollection <T> existingNodes, MergeableNode <T> node, int index)
{
if (!CloneNodesOnMerge)
{
// Moving nodes - destroying the input collection:
node.Parent?.Children?.Remove(node); // First detach node from parent.
existingNodes.Insert(index, node);
}
else
{
// Copying nodes - leaving the input collection intact.
var copy = new MergeableNode <T>(node.Content);
existingNodes.Insert(index, copy);
// Process children
if (node.Children != null && node.Children.Count > 0)
{
EnsureChildren(copy);
Merge(copy.Children, node.Children);
}
}
}
protected override void SetParent(MergeableNode <T> child, MergeableNode <T> parent)
{
child.Parent = parent;
}
protected override MergeableNode <T> GetParent(MergeableNode <T> child)
{
return(child.Parent);
}
/// <summary>
/// Gets the children of the specified node.
/// </summary>
/// <param name="node">The node.</param>
/// <returns>The children of <paramref name="node"/>.</returns>
private static IEnumerable <MergeableNode <T> > GetChildren(MergeableNode <T> node)
{
return(node.Children ?? Enumerable.Empty <MergeableNode <T> >());
}
private void Merge(MergeableNodeCollection <T> targetNodes, MergeableNode <T> node)
{
if (node == null)
{
return;
}
if (node.Content == null)
{
throw new NotSupportedException("Cannot merge nodes. MergeableNode must not be empty (Content != null).");
}
if (node.MergePoints == null)
{
return;
}
foreach (var mergePoint in node.MergePoints)
{
string targetName = mergePoint.Target;
var mergeOperation = mergePoint.Operation;
if (mergeOperation == MergeOperation.Ignore)
{
return; // Ignore this node.
}
// Check whether node with the same action name already exists.
int indexOfExistingNode = FindTargetNode(targetNodes, node.Content.Name);
bool nodeExists = (indexOfExistingNode >= 0);
int indexOfTarget = -1;
bool targetFound = false;
// Find target node.
// (MergeOperation.Append and MergeOperation.Prepend do not need a target node.)
if (!nodeExists && mergeOperation != MergeOperation.Append && mergeOperation != MergeOperation.Prepend)
{
indexOfTarget = FindTargetNode(targetNodes, targetName);
targetFound = (indexOfTarget >= 0);
if (!targetFound)
{
continue; // Target not found. Try next merge point.
}
}
switch (mergeOperation)
{
case MergeOperation.Ignore:
// Do nothing.
Debug.Fail("We should never get here, cause all MergeOperation.Ignore are handled above.");
break;
case MergeOperation.Match:
// Do not add this node, but merge children
Debug.Assert(nodeExists || targetFound, "Sanity check.");
if (nodeExists)
{
if (node.Children != null && node.Children.Count > 0)
{
var targetNode = targetNodes[indexOfExistingNode];
EnsureChildren(targetNode);
Merge(targetNode.Children, node.Children);
}
}
else
{
if (node.Children != null && node.Children.Count > 0)
{
var targetNode = targetNodes[indexOfTarget];
EnsureChildren(targetNode);
Merge(targetNode.Children, node.Children);
}
}
break;
case MergeOperation.Prepend:
// Merge node with existing node, or prepend at the beginning.
if (nodeExists)
{
OnMerge(targetNodes[indexOfExistingNode], node);
}
else
{
OnInsert(targetNodes, node, 0);
}
break;
case MergeOperation.Append:
// Merge node with existing node, or append at the end.
if (nodeExists)
{
OnMerge(targetNodes[indexOfExistingNode], node);
}
else
{
OnInsert(targetNodes, node, targetNodes.Count);
}
break;
case MergeOperation.InsertBefore:
// Merge node with existing, or insert before merge point.
Debug.Assert(nodeExists || targetFound, "Sanity check.");
if (nodeExists)
{
OnMerge(targetNodes[indexOfExistingNode], node);
}
else
{
OnInsert(targetNodes, node, indexOfTarget);
}
break;
case MergeOperation.InsertAfter:
// Merge node with existing or insert after merge point.
Debug.Assert(nodeExists || targetFound, "Sanity check.");
if (nodeExists)
{
OnMerge(targetNodes[indexOfExistingNode], node);
}
else
{
OnInsert(targetNodes, node, indexOfTarget + 1);
}
break;
case MergeOperation.Replace:
// Replace existing node (or node at merge point).
Debug.Assert(nodeExists || targetFound, "Sanity check.");
if (nodeExists)
{
targetNodes.RemoveAt(indexOfExistingNode);
OnInsert(targetNodes, node, indexOfExistingNode);
}
else
{
targetNodes.RemoveAt(indexOfTarget);
OnInsert(targetNodes, node, indexOfTarget);
}
break;
case MergeOperation.Remove:
// Remove existing node (or node at merge point)
Debug.Assert(nodeExists || targetFound, "Sanity check.");
if (nodeExists)
{
targetNodes.RemoveAt(indexOfExistingNode);
}
else
{
targetNodes.RemoveAt(indexOfTarget);
}
break;
}
}
}
