/// <summary>
/// Applies an operation based on another site document (defined by a list of ids of operations that were applied prior to this one)
/// and adjusts the supplied caret index as appropriate
/// </summary>
/// <param name="appliedOperation"></param>
/// <param name="caretIndex"></param>
public void ApplyTransform(AppliedOperation appliedOperation, ref int caretIndex)
{
var missingRemoteTransformIds = _AppliedOperationsOrder.Except(appliedOperation.PriorStateTransformIds);
var operation = appliedOperation.Operation;
foreach (var id in missingRemoteTransformIds.Reverse())
{
operation = OperationTransformer.Transform(operation, _AppliedOperations[id]);
}
TransformState(operation);
if (operation.Position < caretIndex)
{
if (operation is InsertOperation)
{
caretIndex += operation.Length;
caretIndex = Math.Min(caretIndex, CurrentState.Length);
}
else if (operation is DeleteOperation)
{
caretIndex -= operation.Length;
caretIndex = Math.Max(caretIndex, 0);
}
}
}
private IRequest TransformRequest(IRequest request)
{
if (request.Revision == _revision)
{
return(request);
}
if (request.Revision > _revision)
{
throw new System.ApplicationException("Request revision is ahead of server revision.");
}
IRequest tempRequest = request;
// get operations from revision log since request revision number
var logOperations = _revisionLog
.Where(pair => pair.Key >= tempRequest.Revision)
.OrderBy(pair => pair.Key).ToList();
List <IOperation> transformedOperations = new List <IOperation>(tempRequest.Operations);
foreach (var(revision, operations) in logOperations)
{
List <IOperation> temp = OperationTransformer.Transform(transformedOperations, operations).ToList();
transformedOperations = new List <IOperation>(temp);
tempRequest = RequestFactory.CreateRequest(tempRequest.ClientId, revision, transformedOperations);
}
return(tempRequest);
}
private void HandleReceivedRequests()
{
if (_receivedRequests.IsEmpty)
{
return;
}
if (!_receivedRequests.TryDequeue(out IRequest request))
{
return;
}
lock (_locker)
{
// check if request is acknowledgment for the awaiting request
if (request.IsAcknowledged &&
request.ClientId == ClientId &&
_awaitingRequests.Count() != 0 &&
request.Operations.All(o1 => _awaitingRequests.First().Operations.Any(o2 => o1.Timestamp == o2.Timestamp)))
{
_awaitingRequests.Clear();
_revision = request.Revision;
// logging
if (_logginEnabled)
{
_logger.LogWriteLine($"Client with ID: '{ClientId}' recieved ack message");
}
return;
}
IRequest transformedRequest = request;
// transform operations in buffer according to the received request operations
if (!_operationsBuffer.IsEmpty)
{
List <IOperation> transformedOperations = OperationTransformer.Transform(_operationsBuffer.ToList(), request.Operations.ToList()).ToList();
_operationsBuffer.Clear();
foreach (IOperation operation in transformedOperations)
{
_operationsBuffer.Enqueue(operation);
}
}
// transform incomming request operations according to the awating request operations
if (_awaitingRequests.Count() != 0)
{
List <IOperation> transformedOperations = OperationTransformer.Transform(request.Operations.ToList(), _awaitingRequests.First().Operations.ToList()).ToList();
transformedRequest = RequestFactory.CreateRequest(request.ClientId, request.Revision, transformedOperations, request.IsAcknowledged);
}
_revision = request.Revision;
ApplyOperations(transformedRequest.Operations.ToList());
if (_logginEnabled)
{
_logger.LogWriteLine($"Client with ID: '{ClientId}' processed incoming request");
}
}
}
public void OperationTransformer_TransformDeleteDelete_LocalEqualToRemote()
{
var state = new DocumentState(1, "123456789");
var localOperation = new DeleteOperation(state, 2);
var remoteOperation = new DeleteOperation(state, 2);
var transformed = OperationTransformer.Transform(remoteOperation, localOperation);
var stateStr = state.CurrentState;
stateStr = localOperation.ApplyTransform(stateStr);
stateStr = transformed.ApplyTransform(stateStr);
Assert.AreEqual("12456789", stateStr);
}
public void OperationTransformer_TransformInsertDelete_LocalBeforeRemote()
{
var state = new DocumentState(1, "123456789");
var localOperation = new InsertOperation(state, 2, 'a');
var remoteOperation = new DeleteOperation(state, 4);
var transformed = OperationTransformer.Transform(remoteOperation, localOperation);
var stateStr = state.CurrentState;
stateStr = localOperation.ApplyTransform(stateStr);
stateStr = transformed.ApplyTransform(stateStr);
Assert.AreEqual("12a346789", stateStr);
}
public void OperationTransformer_TransformInsertInsert_LocalEqualToRemote()
{
var localState = new DocumentState(0, "123456789");
var remoteState = new DocumentState(1, "123456789");
var localOperation = new InsertOperation(localState, 2, 'a');
var remoteOperation = new InsertOperation(remoteState, 2, 'b');
var transformed = OperationTransformer.Transform(remoteOperation, localOperation);
var stateStr = localState.CurrentState;
stateStr = localOperation.ApplyTransform(stateStr);
stateStr = transformed.ApplyTransform(stateStr);
Assert.AreEqual("12ba3456789", stateStr);
}
public void OperationTransformer_Transform_CP1TP1Satisfied()
{
var site1Str = "abcd";
var site2Str = "abcd";
var site1 = new DocumentState(1, site1Str);
var site2 = new DocumentState(2, site2Str);
var op1 = new InsertOperation(site1, 0, '1');
var op2 = new InsertOperation(site2, 0, '2');
site1Str = op2.ApplyTransform(site1Str);
site1Str = OperationTransformer.Transform(op1, op2).ApplyTransform(site1Str);
site2Str = op1.ApplyTransform(site2Str);
site2Str = OperationTransformer.Transform(op2, op1).ApplyTransform(site2Str);
Assert.AreEqual(site1Str, site2Str);
}
public void OperationTransformer_Transform_CP2TP2Satisfied()
{
var site1Str = "abcd";
var site2Str = "abcd";
var site3Str = "abcd";
var site1 = new DocumentState(1, site1Str);
var site2 = new DocumentState(2, site2Str);
var site3 = new DocumentState(3, site3Str);
var op1 = new InsertOperation(site1, 0, '1');
var op2 = new InsertOperation(site2, 1, '2');
var op3 = new InsertOperation(site3, 2, '3');
var op2dash = OperationTransformer.Transform(op2, op1);
var op3dashV1 = OperationTransformer.Transform(OperationTransformer.Transform(op3, op1), op2dash);
var op1dash = OperationTransformer.Transform(op1, op2);
var op3dashV2 = OperationTransformer.Transform(OperationTransformer.Transform(op3, op2), op1dash);
Assert.IsTrue(op3dashV1.IdenticalOperation(op3dashV2));
}
[TestMethod][Ignore] // TODO: Get IP2 succeeding (if needed)
public void OperationTransformer_Transform_IP2Satisfied()
{
var output = new List <(OperationBase op1, OperationBase op2, string message)>();
foreach (var opPair in GetOperationPairs())
{
var opx = opPair.op1;
var op = opPair.op2;
OperationBase opUndo = op.CreateInverse(opPair.ds2);
if (!opx.IdenticalOperation(OperationTransformer.Transform(opx, OperationTransformer.Transform(op, opUndo))))
{
output.Add((opx, op,
$"{Environment.NewLine}IP2 failed with opx = {opx} and op = {op}"));
// TODO: This needs to pass to support undo properly. Basically this is ensuring that transforming op2 by op1 then op1undone is the same as op2 on its own
}
}
if (output.Count != 0)
{
Assert.Fail(string.Join(string.Empty, output.Select(o => o.message)));
}
}
