public void Update(TContext context, BasePrimitive <TItem> current, BasePrimitive <TItem> next)
{
var currentList = current?.Attributes.GetAttributeOrDefault(_attribute);
var nextList = next?.Attributes.GetAttributeOrDefault(_attribute);
// get an id to allow for easy viewing
long loggingId = 0;
if (IsLoggingEnabled.Value)
{
loggingId = Interlocked.Increment(ref LoggingId);
Logging.Instance.LogInformation("CollectionUpdate:Begin {id} current Length:{currentLength} next Length:{nextLength}", loggingId, currentList?.Length ?? 0, nextList?.Length ?? 0);
}
IEnumerable <Operation <TTarget> > operations;
// get a list of operations that transform currentList to nextList
IReadOnlyList <Operation <TTarget> > comparisonOperations;
if (IsLoggingEnabled.Value)
{
using var _ = Benchmark.Create((d, __) =>
{
Logging.Instance.LogInformation("CollectionUpdate:Timings {id} duration:{duration}ms, algorithm:{algorithm}", loggingId, d, _collectionComparer.GetType().FriendlyName());
});
comparisonOperations = _collectionComparer.Compare(currentList, nextList);
}
else
{
comparisonOperations = _collectionComparer.Compare(currentList, nextList);
}
if (IsLoggingEnabled.Value)
{
Logging.Instance.LogInformation("CollectionUpdate:Raw {id} change count:{count}", loggingId, comparisonOperations.Count);
}
// only perform an attempt at a compaction if there is an insert and a delete both in existence
if (comparisonOperations.Count >= 2 && comparisonOperations.Any(f => f.GetType() == typeof(DeleteOp <IPrimitive>)) && comparisonOperations.Any(f => f.GetType() == typeof(InsertOp <IPrimitive>)))
{
if (IsLoggingEnabled.Value)
{
Logging.Instance.LogInformation("CollectionUpdate:Compacting Changes");
}
// create our collection change compactor which will look to reduce the number of updates made
var collectionChangeCompactor = new CollectionChangeCompactor <TTarget>(currentList ?? nextList);
foreach (var operation in comparisonOperations)
{
switch (operation)
{
case InsertOp <TTarget> op:
collectionChangeCompactor.Insert(op.Index, op.Item);
break;
case DeleteOp <TTarget> op:
collectionChangeCompactor.Delete(op.Index);
break;
case MoveOp <TTarget> op:
collectionChangeCompactor.Delete(op.From);
collectionChangeCompactor.Insert(op.To, op.Item);
break;
case UpdateOp <TTarget> op:
collectionChangeCompactor.Update(op.Index, op.ToItem);
break;
}
}
operations = collectionChangeCompactor.GetChangOps();
}
else
{
operations = comparisonOperations;
}
// now apply changes
foreach (var operation in operations)
{
switch (operation)
{
case UpdateOp <TTarget> op:
if (IsLoggingEnabled.Value)
{
Logging.Instance.LogInformation("CollectionUpdate:Update {id} {index}:{item}", loggingId, op.Index, op.FromItem, op.ToItem);
}
_connector.Update(op.Index, op.FromItem, op.ToItem);
break;
case DeleteOp <TTarget> op:
if (IsLoggingEnabled.Value)
{
Logging.Instance.LogInformation("CollectionUpdate:Delete {id} {index}:{item}", loggingId, op.Index, op.Item);
}
_connector.Remove(op.Index, op.Item);
break;
case InsertOp <TTarget> op:
if (IsLoggingEnabled.Value)
{
Logging.Instance.LogInformation("CollectionUpdate:Insert {id} {index}:{item}", loggingId, op.Index, op.Item);
}
_connector.Insert(op.Index, op.Item);
break;
default:
throw new ArgumentOutOfRangeException();
}
}
if (IsLoggingEnabled.Value)
{
Logging.Instance.LogInformation("CollectionUpdate:End {id}", loggingId);
}
}