/// <summary>
/// Updates the reference to the node within the table.
/// </summary>
/// <param name="nodeId"></param>
/// <param name="nodeData"></param>
/// <param name="nodeEvents"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
public ValueTask TouchAsync(TKNodeId nodeId, TKNodeData nodeData = default, IKNodeEvents nodeEvents = null, CancellationToken cancellationToken = default)
{
return(GetBucket(nodeId).TouchAsync(nodeId, nodeData, nodeEvents, protocol, cancellationToken));
}
/// <summary>
/// Initializes a new instance.
/// </summary>
/// <param name="id"></param>
/// <param name="data"></param>
/// <param name="events"></param>
public KBucketItem(TKNodeId id, TKNodeData data, IKNodeEvents events)
{
this.id = id;
this.data = data;
this.events = events;
}
/// <summary>
/// Updates the position of the node in the bucket.
/// </summary>
/// <typeparam name="TKNetwork"></typeparam>
/// <param name="nodeId"></param>
/// <param name="nodeData"></param>
/// <param name="nodeEvents"></param>
/// <param name="protocol"></param>
/// <param name="cancellationToken"></param>
internal async ValueTask TouchAsync(TKNodeId nodeId, TKNodeData nodeData, IKNodeEvents nodeEvents, IKNodeProtocol <TKNodeId, TKNodeData> protocol, CancellationToken cancellationToken)
{
var lk = rw.BeginUpgradableReadLock();
try
{
var i = GetNode(nodeId);
if (i != null)
{
using (rw.BeginWriteLock())
{
// item already exists, move to tail
l.Remove(i);
l.AddLast(i.Value);
}
}
else if (l.Count < k)
{
using (rw.BeginWriteLock())
{
// item does not exist, but bucket has room, insert at tail
l.AddLast(new KBucketItem <TKNodeId, TKNodeData>(nodeId, nodeData, nodeEvents));
}
}
else
{
// item does not exist, but bucket does not have room, ping first entry
var n = l.First;
// start ping, check for async completion
KNodePingResponse r;
var t = protocol.PingAsync(n.Value.Id, n.Value.Data, cancellationToken);
// completed synchronously (or immediately)
if (t.IsCompleted)
{
r = t.Result;
}
else
{
// temporarily release lock and wait for completion
lk.Dispose();
r = await t;
lk = rw.BeginUpgradableReadLock();
}
// was able to successfully ping the node
if (r.Status == KNodeResponseStatus.OK)
{
// entry had response, move to tail, discard new entry
if (l.Count > 1)
{
using (rw.BeginWriteLock())
{
// remove from list if not already done (async operation could have overlapped)
if (n.List != null)
{
l.Remove(n);
}
// node goes to end
l.AddLast(n.Value);
}
}
}
else
{
using (rw.BeginWriteLock())
{
// first entry had no response, remove, insert new at tail
l.Remove(n);
l.AddLast(new KBucketItem <TKNodeId, TKNodeData>(nodeId, nodeData, nodeEvents));
}
}
}
}
finally
{
lk.Dispose();
}
}
