/// <summary>
/// Implements operational transforms as per http://cooffice.ntu.edu.sg/otfaq/ 2.15
/// It take a remote operation, that was indented to be applied to a document that hadn't yet had the local operation
/// applied, and translates it to one that maintains the intent when used one a document that did have the local operation applied.
/// </summary>
/// <param name="remoteOperation">The remote operation we want to transform</param>
/// <param name="localOperation">The local operation we want to transform using</param>
/// <returns></returns>
public static OperationBase Transform(OperationBase remoteOperation, OperationBase localOperation)
{
switch (remoteOperation)
{
case InsertOperation remoteInsert:
switch (localOperation)
{
case InsertOperation localInsert: return(TransformInsertInsert(remoteInsert, localInsert));
case DeleteOperation localDelete: return(TransformInsertDelete(remoteInsert, localDelete));
case IdentityOperation localIdentity: return(remoteOperation);
default: throw new InvalidOperationException();
}
case DeleteOperation remoteDelete:
switch (localOperation)
{
case InsertOperation localInsert: return(TransformDeleteInsert(remoteDelete, localInsert));
case DeleteOperation localDelete: return(TransformDeleteDelete(remoteDelete, localDelete));
case IdentityOperation localIdentity: return(remoteOperation);
default: throw new InvalidOperationException();
}
case IdentityOperation remoteIdentity: return(remoteOperation);
default: throw new InvalidOperationException();
}
}
public bool IdenticalOperation(OperationBase other)
{
if (other == null)
{
return(false);
}
if (GetType() != other.GetType())
{
return(false);
}
return(Position == other.Position && Text == other.Text);
}
/// <summary> /// Create a new applied operation against a site with no prior transformations /// </summary> /// <param name="operation"></param> internal AppliedOperation(OperationBase operation) => Operation = operation;