public static List <RdTextChange> ToRdTextChanges(this OtOperation op)
{
var documentLength = op.DocumentLengthBefore();
var currOffset = 0;
InsertText lastInsert = null;
DeleteText lastDelete = null;
var res = new List <RdTextChange>();
foreach (var change in op.Changes)
{
switch (change)
{
case Retain _:
{
if (lastDelete != null || lastInsert != null)
{
res.Add(CreateTextChange(currOffset, lastInsert, lastDelete, documentLength));
lastDelete = null;
lastInsert = null;
}
break;
}
case InsertText i:
{
if (lastInsert != null)
{
res.Add(CreateTextChange(currOffset, lastInsert, lastDelete, documentLength));
lastDelete = null;
}
documentLength += change.GetTextLengthAfter();
lastInsert = i;
break;
}
case DeleteText d:
{
if (lastDelete != null)
{
res.Add(CreateTextChange(currOffset, lastInsert, lastDelete, documentLength));
lastInsert = null;
}
documentLength -= change.GetTextLengthBefore();
lastDelete = d;
break;
}
}
currOffset += change.GetTextLengthAfter();
}
if (lastDelete != null || lastInsert != null)
{
res.Add(CreateTextChange(currOffset, lastInsert, lastDelete, documentLength));
}
return(res);
}
/*
* public static OtOperation Compose(this OtOperation o1, OtOperation o2)
* {
* var after = o1.DocumentLengthAfter();
* var before = o2.DocumentLengthBefore();
*
* Assertion.Assert(after == before, "after == before");
* Assertion.Assert(o1.Origin == o2.Origin, "o1.Role == o2.Role");
* Assertion.Assert(o1.Timestamp == o2.Timestamp, "o1.Timestamp == o2.Timestamp");
* Assertion.Assert(o1.Kind == o2.Kind, "o1.Kind == o2.Kind");
*
*
* var ops1 = new Stack<OtChange>(Enumerable.Reverse(o1.Changes));
* var ops2 = new Stack<OtChange>(Enumerable.Reverse(o2.Changes));
* var acc = new List<OtChange>();
*
* while (true)
* {
* var op1 = ops1.Count != 0 ? ops1.Peek() : null;
* var op2 = ops2.Count != 0 ? ops2.Peek() : null;
*
* if (op1 == null && op2 == null)
* break;
*
* if (op1 != null && op2 == null)
* {
* acc.Add(op1);
* ops1.Pop();
* continue;
* }
*
* if (op1 == null && op2 != null)
* {
* acc.Add(op2);
* ops2.Pop();
* continue;
* }
*
* switch (op1)
* {
* case DeleteText d1 when op2 is InsertText d2 && d1.Text == d2.Text:
* {
* var length = d1.Text.Length;
* acc.Add(new Retain(length));
* ops1.Pop();
* ops2.Pop();
* break;
* }
* case OtChange _ when op2 is InsertText:
* {
* acc.Add(op2);
* ops2.Pop();
* break;
* }
* case DeleteText _ when op2 != null:
* {
* acc.Add(op1);
* ops1.Pop();
* break;
* }
* case Retain r1 when op2 is Retain r2:
* {
* var offset1 = r1.Offset;
* var offset2 = r2.Offset;
* if (offset1 > offset2)
* {
* acc.Add(op2);
* ops1.Pop();
* ops2.Pop();
* ops1.Push(new Retain(offset1 - offset2));
* }
* else if (offset1 == offset2)
* {
* acc.Add(op1);
* ops1.Pop();
* ops2.Pop();
* }
* else if (offset1 < offset2)
* {
* acc.Add(op1);
* ops1.Pop();
* ops2.Pop();
* ops2.Push(new Retain(offset2 - offset1));
* }
*
* break;
* }
* case InsertText i1 when op2 is DeleteText d2:
* {
* var text1 = i1.Text;
* var text2 = d2.Text;
* if (text1.Length > text2.Length)
* {
* Assertion.Assert(text1.StartsWith(text2), "text1.StartsWith(text2)");
* ops1.Pop();
* ops2.Pop();
* ops1.Push(new InsertText(text1.Substring(text2.Length)));
* }
* else if (text1.Length == text2.Length)
* {
* Assertion.Assert(text1 == text2, "text1 == text2");
* ops1.Pop();
* ops2.Pop();
* }
* else if (text1.Length < text2.Length)
* {
* Assertion.Assert(text2.StartsWith(text1), "text2.StartsWith(text1)");
* ops1.Pop();
* ops2.Pop();
* ops2.Push(new DeleteText(text2.Substring(text1.Length)));
* }
*
* break;
* }
* case InsertText i1 when op2 is Retain r2:
* {
* var text1 = i1.Text;
* var offset2 = r2.Offset;
* if (text1.Length > offset2)
* {
* acc.Add(new InsertText(text1.Substring(0, offset2)));
* ops1.Pop();
* ops2.Pop();
* ops1.Push(new InsertText(text1.Substring(offset2)));
* }
* else if (text1.Length == offset2)
* {
* acc.Add(op1);
* ops1.Pop();
* ops2.Pop();
* }
* else if (text1.Length < offset2)
* {
* acc.Add(op1);
* ops1.Pop();
* ops2.Pop();
* ops2.Push(new Retain(offset2 - text1.Length));
* }
*
* break;
* }
* case Retain r1 when op2 is DeleteText d2:
* {
* var offset1 = r1.Offset;
* var text2 = d2.Text;
* if (offset1 > text2.Length)
* {
* acc.Add(op2);
* ops1.Pop();
* ops2.Pop();
* ops1.Push(new Retain(offset1 - text2.Length));
* }
* else if (offset1 == text2.Length)
* {
* acc.Add(op2);
* ops1.Pop();
* ops2.Pop();
* }
* else if (offset1 < text2.Length)
* {
* acc.Add(new DeleteText(text2.Substring(0, offset1)));
* ops1.Pop();
* ops2.Pop();
* ops2.Push(new DeleteText(text2.Substring(offset1)));
* }
*
* break;
* }
* default: throw new ArgumentOutOfRangeException($"Not matched pair: (op1 = {op1}, op2 = {op2})");
* }
* }
*
* return new OtOperation(acc, o1.Origin, o1.Timestamp, o1.Kind);
* }
*/
// Ressel’s transformation function
public static OtTransformResult Transform(OtOperation localDiff, OtOperation remoteApplyToDocument)
{
Assertion.Assert(localDiff.DocumentLengthBefore() == remoteApplyToDocument.DocumentLengthBefore(),
"localDiff.DocumentLengthBefore() == remoteApplyToDocument.DocumentLengthBefore()");
Assertion.Assert(localDiff.Origin != remoteApplyToDocument.Origin, "localDiff.Role != remoteApplyToDocument.Role");
Assertion.Assert(localDiff.Kind == OtOperationKind.Normal && remoteApplyToDocument.Kind == OtOperationKind.Normal,
"localDiff.Kind == OtOperationKind.Normal && remoteApplyToDocument.Kind == OtOperationKind.Normal");
var resOp1 = new List <OtChange>();
var resOp2 = new List <OtChange>();
var ops1 = new Stack <OtChange>(Enumerable.Reverse(localDiff.Changes));
var ops2 = new Stack <OtChange>(Enumerable.Reverse(remoteApplyToDocument.Changes));
while (true)
{
var op1 = ops1.Count != 0 ? ops1.Peek() : null;
var op2 = ops2.Count != 0 ? ops2.Peek() : null;
if (op1 == null && op2 == null)
{
break;
}
if (op1 == null && op2 != null)
{
var offset = op2.GetTextLengthAfter();
if (offset > 0)
{
resOp1.Add(new Retain(offset));
resOp2.Add(op2);
ops2.Pop();
}
else
{
resOp2.Add(op2);
ops2.Pop();
}
continue;
}
if (op1 != null && op2 == null)
{
var offset = op1.GetTextLengthAfter();
if (offset > 0)
{
resOp1.Add(op1);
resOp2.Add(new Retain(offset));
ops1.Pop();
}
else
{
resOp2.Add(op1);
ops1.Pop();
}
continue;
}
switch (op1)
{
case InsertText i1 when op2 is InsertText i2:
{
if (localDiff.Origin < remoteApplyToDocument.Origin)
{
resOp1.Add(i1);
resOp2.Add(new Retain(i1.Text.Length));
ops1.Pop();
}
else
{
resOp1.Add(new Retain(i2.Text.Length));
resOp2.Add(op2);
ops2.Pop();
}
break;
}
case InsertText i1:
{
resOp1.Add(i1);
resOp2.Add(new Retain(i1.Text.Length));
ops1.Pop();
break;
}
case var _ when op2 is InsertText i2:
{
resOp1.Add(new Retain(i2.Text.Length));
resOp2.Add(i2);
ops2.Pop();
break;
}
case Retain r1 when op2 is Retain r2:
{
var offset1 = r1.Offset;
var offset2 = r2.Offset;
if (offset1 > offset2)
{
resOp1.Add(op2);
resOp2.Add(op2);
ops1.Pop();
ops2.Pop();
ops1.Push(new Retain(offset1 - offset2));
}
else if (offset1 == offset2)
{
resOp1.Add(op1);
resOp2.Add(op1);
ops1.Pop();
ops2.Pop();
}
else if (offset1 < offset2)
{
resOp1.Add(op1);
resOp2.Add(op1);
ops1.Pop();
ops2.Pop();
ops2.Push(new Retain(offset2 - offset1));
}
break;
}
case DeleteText d1 when op2 is DeleteText d2:
{
var text1 = d1.Text;
var text2 = d2.Text;
if (text1.Length > text2.Length)
{
ops1.Pop();
ops2.Pop();
ops1.Push(new DeleteText(text1.Substring(text2.Length)));
}
else if (text1.Length == text2.Length)
{
Assertion.Assert(text1 == text2, "text1 == text2");
ops1.Pop();
ops2.Pop();
}
else if (text1.Length < text2.Length)
{
ops1.Pop();
ops2.Pop();
ops2.Push(new DeleteText(text2.Substring(text1.Length)));
}
break;
}
case DeleteText d1 when op2 is Retain r2:
{
var text1 = d1.Text;
var offset2 = r2.Offset;
if (text1.Length > offset2)
{
resOp1.Add(new DeleteText(text1.Substring(0, offset2)));
ops1.Pop();
ops2.Pop();
ops1.Push(new DeleteText(text1.Substring(offset2)));
}
else if (text1.Length == offset2)
{
resOp1.Add(op1);
ops1.Pop();
ops2.Pop();
}
else if (text1.Length < offset2)
{
resOp1.Add(op1);
ops1.Pop();
ops2.Pop();
ops2.Push(new Retain(offset2 - text1.Length));
}
break;
}
case Retain r1 when op2 is DeleteText r2:
{
var offset1 = r1.Offset;
var text2 = r2.Text;
if (offset1 > text2.Length)
{
resOp2.Add(op2);
ops1.Pop();
ops2.Pop();
ops1.Push(new Retain(offset1 - text2.Length));
}
else if (offset1 == text2.Length)
{
resOp2.Add(op2);
ops1.Pop();
ops2.Pop();
}
else if (offset1 < text2.Length)
{
resOp2.Add(new DeleteText(text2.Substring(0, offset1)));
ops1.Pop();
ops2.Pop();
ops2.Push(new DeleteText(text2.Substring(offset1)));
}
break;
}
default: throw new ArgumentOutOfRangeException($"Not matched pair: (op1 = {op1}, op2 = {op2})");
}
}
return(new OtTransformResult(
new OtOperation(resOp1, localDiff.Origin, localDiff.Timestamp, OtOperationKind.Normal),
new OtOperation(resOp2, remoteApplyToDocument.Origin, remoteApplyToDocument.Timestamp, OtOperationKind.Normal)));
}
