private void UndoOp(DocumentModel doc, BaseOpMessage op, ITextEdit edit)
{
switch (op.MessageType)
{
case "insert":
var insert = (OpInsertMessage)op;
this.UndoInsert(doc, insert, edit);
break;
case "delete":
var delete = (OpDeleteMessage)op;
this.UndoDelete(doc, delete, edit);
break;
case "replace":
var replace = (OpReplaceMessage)op;
this.UndoReplace(doc, replace, edit);
break;
}
}
private int RedoOp(DocumentModel doc, BaseOpMessage op, ITextEdit edit)
{
var len = 0;
switch (op.MessageType)
{
case "insert":
var insert = (OpInsertMessage)op;
len = insert.Content.Length;
this.Insert(doc, insert, edit);
break;
case "delete":
var delete = (OpDeleteMessage)op;
len = delete.Index - delete.End;
this.Delete(doc, delete, edit);
break;
case "replace":
var replace = (OpReplaceMessage)op;
len = replace.OldContent.Length - replace.Content.Length;
this.Replace(doc, replace, edit);
break;
}
return len;
}
private int DoOp(DocumentModel doc, ITextEdit edit, BaseOpMessage op)
{
var len = 0;
switch (op.MessageType)
{
case "insert":
var insert = op as OpInsertMessage;
len = insert.Content.Length;
doc.Changes.Add(insert);
this.Insert(doc, insert, edit);
break;
case "delete":
var delete = op as OpDeleteMessage;
len = delete.Index - delete.End;
doc.Changes.Add(delete);
this.Delete(doc, delete, edit);
break;
case "replace":
var replace = op as OpReplaceMessage;
len = replace.OldContent.Length - replace.Content.Length;
doc.Changes.Add(replace);
this.Replace(doc, replace, edit);
break;
}
return len;
}
private int MoveOp(BaseOpMessage winner, BaseOpMessage loser)
{
var offset = 0;
// the loser only needs to move if its position is after the winner
if (loser.Index >= winner.Index)
{
switch (winner.MessageType)
{
case "insert":
var i = winner as OpInsertMessage;
offset = i.Content.Length;
break;
case "delete":
var d = winner as OpDeleteMessage;
offset = d.Index - d.End;
break;
case "replace":
var r = winner as OpReplaceMessage;
offset = r.Content.Length - r.OldContent.Length;
break;
}
switch (loser.MessageType)
{
case "insert":
loser.Index += offset;
break;
case "delete":
var d = winner as OpDeleteMessage;
d.Index += offset;
d.End += offset;
break;
case "replace":
var r = winner as OpReplaceMessage;
r.Index += offset;
r.End += offset;
break;
}
}
return offset;
}
/// <summary>
/// Resolves the operations.
/// </summary>
/// <param name="doc">The doc.</param>
/// <param name="remote">The remote.</param>
/// <param name="local">The local.</param>
public static void Resolve(DocumentModel doc, BaseOpMessage remoteOp, BaseOpMessage localOp)
{
if (remoteOp is OpDeleteMessage)
{
var remote = remoteOp as OpDeleteMessage;
Debug.WriteLine("Remote: {0} Delete", remote.User);
if (localOp is OpDeleteMessage)
{
var local = localOp as OpDeleteMessage;
int noOpLength = 0;
if (remote.Index < local.Index)
{
// no overlap, remote OK as is, local needs modifications
local.Index = local.Index - remote.ReplacementLength;
}
else if (remote.Index + remote.ReplacementLength < local.Index + local.ReplacementLength)
{
// remote del at lower index reaches into locally
// applied del, local del reaches further out
// --> shorten remote del appropriately, move and
// shorten local del left
remote.Length = (remote.Index + remote.ReplacementLength) - local.Index;
local.Length = (remote.Index + remote.ReplacementLength) - local.Index;
local.Index = remote.Index;
}
else if ((remote.Index + remote.ReplacementLength >= local.Index + local.ReplacementLength))
{
// remote del at lower index, remote del fully extends
// over local del
// --> shorten remote by local length
// make local no-op
remote.ReplacementLength = remote.ReplacementLength - local.ReplacementLength;
// TODO: verify this...
local.Index = remote.Index;
local.ReplacementLength = noOpLength;
}
else if (remote.Index == local.Index)
{
if (remote.Index + remote.ReplacementLength < local.Index + local.ReplacementLength)
{
// start indeces are equal, remote is shorter
// --> make remote no-op
remote.ReplacementLength = noOpLength;
// --> shorten local to only delete
// non-overlapping region
local.ReplacementLength = local.ReplacementLength - remote.ReplacementLength;
}
else if (remote.Index + remote.ReplacementLength == local.Index + local.ReplacementLength)
{
// same endIndex, same deletion
// --> make remote op be no-op
remote.ReplacementLength = noOpLength;
// --> make local op appear as no-op
local.ReplacementLength = noOpLength;
}
else if (remote.Index + remote.ReplacementLength > local.Index + local.ReplacementLength)
{
// remote del extends over local del
// --> shorten remote del by length of local del,
// index/offset does not need to be updated
remote.ReplacementLength = remote.ReplacementLength - local.ReplacementLength;
// --> make local del appear as no-op
local.ReplacementLength = noOpLength;
}
}
else if (remote.Index > local.Index)
{
if (remote.Index > local.Index + local.ReplacementLength)
{
// move remote delete left by length of local deletion
remote.Index = remote.Index - local.ReplacementLength;
}
else if (remote.Index + remote.ReplacementLength < local.Index + local.ReplacementLength)
{
//remote is fully contained in/overlapping with local del
// --> remote is no-op
remote.ReplacementLength = noOpLength;
// --> local needs to be shortened by length of remote
local.ReplacementLength = local.ReplacementLength - remote.ReplacementLength;
}
else if (remote.Index < local.Index + local.ReplacementLength)
{
// remote del starts within local del, but extends further
// --> shorten remote by overlap and move left
// to index of local del
remote.ReplacementLength = remote.ReplacementLength - (local.Index + local.ReplacementLength) - remote.Index;
}
}
}
else if (localOp is OpInsertMessage)
{
var local = localOp as OpInsertMessage;
if (remote.Index < localOp.Index)
{
if (remote.Index + remote.ReplacementLength < local.Index)
{
// remote remains unchanged, deletion happens fully
// before local insertion
// local insert needs to be moved left by full length of deletion
local.Index -= remote.ReplacementLength;
}
else if (remote.Index + remote.ReplacementLength >= local.Index)
{
// TODO ???
}
else if (remote.Index >= local.Index)
{
// remote del needs to be moved right by full length of insertion
remote.Index += local.Content.Length;
}
}
}
}
else if (remoteOp is OpInsertMessage)
{
var remote = remoteOp as OpInsertMessage;
if (localOp is OpInsertMessage)
{
var local = localOp as OpInsertMessage;
if (remote.Index < local.Index)
{
local.Index += remote.Content.Length;
}
else if (remote.Index == local.Index)
{
var compare = local.User.CompareTo(remote.User);
if (compare < 0)
{
remote.Index += local.Content.Length;
}
else
{
local.Index += remote.Content.Length;
}
}
else if (remote.Index > local.Index)
{
remote.Index += local.Content.Length;
}
}
else if (localOp is OpDeleteMessage)
{
var local = localOp as OpDeleteMessage;
if (remote.Index <= localOp.Index)
{
localOp.Index += remote.Content.Length;
}
else if (remote.Index > localOp.Index)
{
if (remote.Index > local.Index + local.ReplacementLength)
{
remote.Index -= local.ReplacementLength;
}
else if (remote.Index <= local.Index + local.ReplacementLength)
{
// TODO ???
}
}
}
}
}
