protected bool CompareChildren <TNode, TParent>(
NodeComparison <TNode, TParent> compare,
IReadOnlyList <TNode> oldChildren,
IReadOnlyList <TNode> newChildren,
TParent newNodeParent,
CodeModelEventType eventType,
CodeModelEventQueue eventQueue
)
where TNode : SyntaxNode
where TParent : SyntaxNode
{
var oldCount = oldChildren.Count;
var newCount = newChildren.Count;
if (oldCount == newCount)
{
return(FindDifferentChild(
compare,
oldChildren,
newChildren,
newNodeParent,
eventQueue
));
}
else if (Math.Abs(oldCount - newCount) > MaxChildDelta)
{
// We got two discrepancies, enqueue element changed node for containing node
EnqueueChangeEvent(newNodeParent, null, eventType, eventQueue);
}
else
{
if (oldCount > newCount)
{
FindRemovedChild(
compare,
oldChildren,
newChildren,
newNodeParent,
oldCount - newCount,
eventQueue
);
}
else
{
FindAddedChild(
compare,
oldChildren,
newChildren,
newNodeParent,
newCount - oldCount,
eventQueue
);
}
}
return(false);
}
private bool FindDifferentChild <TNode, TParent>(
NodeComparison <TNode, TParent> compare,
IReadOnlyList <TNode> oldChildren,
IReadOnlyList <TNode> newChildren,
TParent newNodeParent,
CodeModelEventQueue eventQueue
)
where TNode : SyntaxNode
where TParent : SyntaxNode
{
Debug.Assert(oldChildren.Count == newChildren.Count);
var eventCount = eventQueue != null ? eventQueue.Count : 0;
var hasChanges = false;
// Find first child that is different.
int i;
for (i = 0; i < oldChildren.Count; i++)
{
if (!compare(oldChildren[i], newChildren[i], newNodeParent, eventQueue))
{
hasChanges = true;
i++;
break;
}
}
// Look for a second different child. If there is one, we'll throw away any events from
// the first different child and enqueue an unknown event on the containing node.
for (; i < oldChildren.Count; i++)
{
if (!compare(oldChildren[i], newChildren[i], newNodeParent, null))
{
// rollback any events added by the first difference
if (eventQueue != null)
{
while (eventQueue.Count > eventCount)
{
eventQueue.Discard();
}
}
EnqueueChangeEvent(
newNodeParent,
null,
CodeModelEventType.Unknown,
eventQueue
);
return(false);
}
}
return(!hasChanges);
}
private void FindRemovedChild <TNode, TParent>(
NodeComparison <TNode, TParent> compare,
IReadOnlyList <TNode> oldChildren,
IReadOnlyList <TNode> newChildren,
TParent newNodeParent,
CodeModelEventType codeModelEventType,
int delta,
CodeModelEventQueue eventQueue)
where TNode : SyntaxNode
where TParent : SyntaxNode
{
Debug.Assert(oldChildren.Count - delta == newChildren.Count);
// The strategy is to assume that all of the removed children are contiguous.
// If that turns out not to be the case, an unknown change event is raised
// for the containing node.
var firstRemoved = -1;
// Look for the first different child. If there is one, track that index as
// the first added node.
int oldIndex, newIndex;
for (oldIndex = 0, newIndex = 0; oldIndex < oldChildren.Count; oldIndex++, newIndex++)
{
if (newIndex >= newChildren.Count || !compare(oldChildren[oldIndex], newChildren[newIndex], newNodeParent, null))
{
firstRemoved = oldIndex;
oldIndex += delta;
break;
}
}
// Look for a second different child. If there is one, we'll throw away any events from
// the first different child and enqueue an unknown event on the containing node.
for (; oldIndex < oldChildren.Count; oldIndex++, newIndex++)
{
if (!compare(oldChildren[oldIndex], newChildren[newIndex], newNodeParent, null))
{
EnqueueChangeEvent(newNodeParent, null, CodeModelEventType.Unknown, eventQueue);
return;
}
}
if (firstRemoved >= 0)
{
for (var i = 0; i < delta; i++)
{
EnqueueRemoveEvent(oldChildren[firstRemoved + i], newNodeParent, eventQueue);
}
}
}
protected DeclarationChange CompareRenamedDeclarations <TNode, TParent>(
NodeComparison <TNode, TParent> compare,
IReadOnlyList <TNode> oldChildren,
IReadOnlyList <TNode> newChildren,
SyntaxNode oldNode,
SyntaxNode newNode,
TParent newNodeParent,
CodeModelEventQueue eventQueue
)
where TNode : SyntaxNode
where TParent : SyntaxNode
{
var oldCount = oldChildren.Count;
var newCount = newChildren.Count;
if (oldCount == newCount)
{
// We now check the children of the old and new types against each other. If any of them have changed,
// it means that the old type has essentially been removed and a new one added.
for (var i = 0; i < oldCount; i++)
{
if (!compare(oldChildren[i], newChildren[i], newNodeParent, null))
{
EnqueueRemoveEvent(oldNode, newNodeParent, eventQueue);
EnqueueAddEvent(newNode, newNodeParent, eventQueue);
// Report that the whole declaration has changed
return(DeclarationChange.WholeDeclaration);
}
}
// The children are all the same, so only the name has changed.
return(DeclarationChange.NameOnly);
}
else
{
// Since the number of members is different, essentially the old type has been removed, and a new one added.
EnqueueRemoveEvent(oldNode, newNodeParent, eventQueue);
EnqueueAddEvent(newNode, newNodeParent, eventQueue);
// Report that the whole declaration has changed
return(DeclarationChange.WholeDeclaration);
}
}
private static bool PerformRecursive(List <NodeBase> nodes)
{
List <NodeBase> valueNodes = new List <NodeBase>();
NodeBase firstNode = nodes[0];
bool isValueNodeLevel = firstNode is ValueNodeBase;
List <List <NodeBase> > childNodeArrays = new List <List <NodeBase> >();
int childNodeCount = firstNode.Children.Count;
for (int i = 0; i < childNodeCount; i++)
{
childNodeArrays.Add(new List <NodeBase>());
childNodeArrays[i].Add(firstNode.Children[i]);
}
for (int i = 1; i < nodes.Count; i++)
{
NodeBase node = nodes[i];
NodeComparison result = firstNode.ShallowCompare(node);
if (result == NodeComparison.Incompatible)
{
return(false);
}
if (isValueNodeLevel)
{
valueNodes.Add(node);
}
else
{
if (result == NodeComparison.Unequal)
{
return(false);
}
// Handle children
for (int j = 0; j < childNodeCount; j++)
{
childNodeArrays[j].Add(node.Children[j]);
}
}
}
if (isValueNodeLevel)
{
if (s_valueDiscrepancy != null) // There is already an existing recorded discrepancy (only one allowed)
{
return(false);
}
s_valueDiscrepancy = new ValueDiscrepancy(valueNodes, (firstNode as ValueNodeBase).TypeIndex);
return(true);
}
for (int i = 0; i < childNodeCount; i++)
{
if (!PerformRecursive(childNodeArrays[i]))
{
return(false);
}
}
return(true);
}
