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/*
* Copyright (c) Contributors, http://opensimulator.org/
* See CONTRIBUTORS.TXT for a full list of copyright holders.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the OpenSimulator Project nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
using System;
using System.Collections.Generic;
using System.Net;
using OpenMetaverse;
namespace OpenSim.Region.ClientStack.LindenUDP
{
/// <summary>
/// Special collection that is optimized for tracking unacknowledged packets
/// </summary>
public sealed class UnackedPacketCollection
{
/// <summary>Synchronization primitive. A lock must be acquired on this
/// object before calling any of the unsafe methods</summary>
public object SyncRoot = new object();
/// <summary>Holds the actual unacked packet data, sorted by sequence number</summary>
private SortedDictionary<uint, OutgoingPacket> packets = new SortedDictionary<uint, OutgoingPacket>();
/// <summary>Gets the total number of unacked packets</summary>
public int Count { get { return packets.Count; } }
/// <summary>
/// Default constructor
/// </summary>
public UnackedPacketCollection()
{
}
/// <summary>
/// Add an unacked packet to the collection
/// </summary>
/// <param name="packet">Packet that is awaiting acknowledgement</param>
/// <returns>True if the packet was successfully added, false if the
/// packet already existed in the collection</returns>
public bool Add(OutgoingPacket packet)
{
lock (SyncRoot)
{
if (!packets.ContainsKey(packet.SequenceNumber))
{
packets.Add(packet.SequenceNumber, packet);
return true;
}
return false;
}
}
/// <summary>
/// Removes a packet from the collection without attempting to obtain a
/// lock first
/// </summary>
/// <param name="sequenceNumber">Sequence number of the packet to remove</param>
/// <returns>True if the packet was found and removed, otherwise false</returns>
public bool RemoveUnsafe(uint sequenceNumber)
{
return packets.Remove(sequenceNumber);
}
/// <summary>
/// Removes a packet from the collection without attempting to obtain a
/// lock first
/// </summary>
/// <param name="sequenceNumber">Sequence number of the packet to remove</param>
/// <param name="packet">Returns the removed packet</param>
/// <returns>True if the packet was found and removed, otherwise false</returns>
public bool RemoveUnsafe(uint sequenceNumber, out OutgoingPacket packet)
{
if (packets.TryGetValue(sequenceNumber, out packet))
{
packets.Remove(sequenceNumber);
return true;
}
return false;
}
/// <summary>
/// Removes all elements from the collection
/// </summary>
public void Clear()
{
lock (SyncRoot)
packets.Clear();
}
/// <summary>
/// Gets the packet with the lowest sequence number
/// </summary>
/// <returns>The packet with the lowest sequence number, or null if the
/// collection is empty</returns>
public OutgoingPacket GetOldest()
{
lock (SyncRoot)
{
using (SortedDictionary<uint, OutgoingPacket>.ValueCollection.Enumerator e = packets.Values.GetEnumerator())
{
if (e.MoveNext())
return e.Current;
else
return null;
}
}
}
/// <summary>
/// Returns a list of all of the packets with a TickCount older than
/// the specified timeout
/// </summary>
/// <param name="timeoutMS">Number of ticks (milliseconds) before a
/// packet is considered expired</param>
/// <returns>A list of all expired packets according to the given
/// expiration timeout</returns>
public List<OutgoingPacket> GetExpiredPackets(int timeoutMS)
{
List<OutgoingPacket> expiredPackets = null;
lock (SyncRoot)
{
int now = Environment.TickCount;
foreach (OutgoingPacket packet in packets.Values)
{
// TickCount of zero means a packet is in the resend queue
// but hasn't actually been sent over the wire yet
if (packet.TickCount == 0)
continue;
if (now - packet.TickCount >= timeoutMS)
{
if (expiredPackets == null)
expiredPackets = new List<OutgoingPacket>();
expiredPackets.Add(packet);
}
else
{
break;
}
}
}
return expiredPackets;
}
}
}
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