public bool RemoveStaleContact(NodeContact contact)
{
KBucket currentBucket = this;
while (true)
{
NodeContact[] contacts;
KBucket leftBucket;
KBucket rightBucket;
lock (currentBucket)
{
contacts = currentBucket._contacts;
leftBucket = currentBucket._leftBucket;
rightBucket = currentBucket._rightBucket;
if (contacts != null)
{
#region remove contact from this bucket
if (currentBucket._contactCount <= DhtNode.KADEMLIA_K)
{
return(false); //k-bucket is not full and replacement cache is empty
}
//check if there is more deserving contact to be removed than the current one
foreach (NodeContact testContact in contacts)
{
if ((testContact != null) && testContact.IsStale() && (contact.SuccessfulRpcCount > testContact.SuccessfulRpcCount))
{
//set test contact for removal
contact = testContact;
break;
}
}
for (int i = 0; i < contacts.Length; i++)
{
if (contact.Equals(contacts[i]))
{
if (contacts[i].IsStale())
{
//remove stale contact
contacts[i] = null;
currentBucket._lastChanged = DateTime.UtcNow;
KBucket bucket = currentBucket;
do
{
Interlocked.Decrement(ref bucket._contactCount);
bucket = bucket._parentBucket;
}while (bucket != null);
return(true);
}
break;
}
}
return(false); //contact was not found or was not stale
#endregion
}
}
if ((leftBucket._bucketID & contact.NodeId) == leftBucket._bucketID)
{
currentBucket = leftBucket;
}
else
{
currentBucket = rightBucket;
}
}
}
public bool AddContact(NodeContact contact)
{
KBucket currentBucket = this;
while (true)
{
NodeContact[] contacts;
KBucket leftBucket;
KBucket rightBucket;
lock (currentBucket)
{
contacts = currentBucket._contacts;
leftBucket = currentBucket._leftBucket;
rightBucket = currentBucket._rightBucket;
if (contacts != null)
{
#region add contact in this bucket
//search if contact already exists
for (int i = 0; i < contacts.Length; i++)
{
if (contact.Equals(contacts[i]))
{
return(false); //contact already exists
}
}
//try add contact
for (int i = 0; i < contacts.Length; i++)
{
if (contacts[i] == null)
{
contacts[i] = contact;
currentBucket._lastChanged = DateTime.UtcNow;
KBucket bucket = currentBucket;
do
{
Interlocked.Increment(ref bucket._contactCount);
bucket = bucket._parentBucket;
}while (bucket != null);
return(true);
}
}
//k-bucket is full so contact was not added
//if current contact is not stale then find and replace with any existing stale contact
if (!contact.IsStale())
{
for (int i = 0; i < contacts.Length; i++)
{
if (contacts[i].IsStale())
{
contacts[i] = contact;
currentBucket._lastChanged = DateTime.UtcNow;
KBucket bucket = currentBucket;
do
{
Interlocked.Increment(ref bucket._contactCount);
bucket = bucket._parentBucket;
}while (bucket != null);
return(true);
}
}
}
//no stale contact in this k-bucket to replace!
if (contacts[0].IsCurrentNode || (currentBucket._bucketDepth < (DhtNode.KADEMLIA_B - 1)))
{
//split current bucket and add contact!
SplitBucket(currentBucket, contact);
KBucket bucket = currentBucket;
do
{
Interlocked.Increment(ref bucket._contactCount);
bucket = bucket._parentBucket;
}while (bucket != null);
return(true);
}
//k-bucket is full!
return(false);
#endregion
}
}
if ((leftBucket._bucketID & contact.NodeId) == leftBucket._bucketID)
{
currentBucket = leftBucket;
}
else
{
currentBucket = rightBucket;
}
}
}
