public override VersionVector Merge(VersionVector other)
{
if (other is MultiVersionVector)
{
var vector = (MultiVersionVector)other;
var v2 = vector.Versions.GetValueOrDefault(Node, 0L);
var mergedVersions = v2 >= Version ? vector.Versions : vector.Versions.SetItem(Node, Version);
return(new MultiVersionVector(mergedVersions));
}
else if (other is SingleVersionVector)
{
var vector = (SingleVersionVector)other;
if (Node == vector.Node)
{
return(Version >= vector.Version ? this : new SingleVersionVector(vector.Node, vector.Version));
}
else
{
return(new MultiVersionVector(
new KeyValuePair <UniqueAddress, long>(Node, Version),
new KeyValuePair <UniqueAddress, long>(vector.Node, vector.Version)));
}
}
else
{
throw new NotSupportedException("SingleVersionVector doesn't support merge with provided version vector");
}
}
public override VersionVector Merge(VersionVector other)
{
if (other is MultiVersionVector)
{
var vector = (MultiVersionVector)other;
var merged = vector.Versions.ToBuilder();
foreach (var pair in Versions)
{
var mergedCurrentTime = merged.GetValueOrDefault(pair.Key, 0L);
if (pair.Value >= mergedCurrentTime)
{
merged.AddOrSet(pair.Key, pair.Value);
}
}
return(new MultiVersionVector(merged.ToImmutable()));
}
else if (other is SingleVersionVector)
{
var vector = (SingleVersionVector)other;
var v1 = Versions.GetValueOrDefault(vector.Node, 0L);
var merged = v1 >= vector.Version ? Versions : Versions.SetItem(vector.Node, vector.Version);
return(new MultiVersionVector(merged));
}
else
{
throw new NotSupportedException("MultiVersionVector doesn't support merge with provided version vector");
}
}
/// <summary>
/// INTERNAL API
/// Subtract the <paramref name="vvector"/> from the <paramref name="dot"/>.
/// What this means is that any (node, version) pair in
/// <paramref name="dot"/> that is <= an entry in <paramref name="vvector"/> is removed from <paramref name="dot"/>.
/// Example [{a, 3}, {b, 2}, {d, 14}, {g, 22}] -
/// [{a, 4}, {b, 1}, {c, 1}, {d, 14}, {e, 5}, {f, 2}] =
/// [{b, 2}, {g, 22}]
/// </summary>
internal static VersionVector SubtractDots(VersionVector dot, VersionVector vvector)
{
if (dot.IsEmpty)
{
return(VersionVector.Empty);
}
if (dot is SingleVersionVector single)
{
// if dot is dominated by version vector, drop it
return(vvector.VersionAt(single.Node) >= single.Version ? VersionVector.Empty : single);
}
if (dot is MultiVersionVector multi)
{
var acc = ImmutableDictionary <UniqueAddress, long> .Empty.ToBuilder();
foreach (var pair in multi.Versions)
{
var v2 = vvector.VersionAt(pair.Key);
if (v2 < pair.Value)
{
acc.Add(pair);
}
}
return(VersionVector.Create(acc.ToImmutable()));
}
throw new NotSupportedException("Cannot subtract dots from provided version vector");
}