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authorJohn Hurliman2009-10-13 18:56:54 -0700
committerJohn Hurliman2009-10-13 18:56:54 -0700
commite8c1e69a0dbab1a7db894eeff6b052bbd350a8f5 (patch)
tree6d29a3bae418c1c5a06e3f1b8ad4a59db57a8d9e /OpenSim/Framework/LocklessQueue.cs
parent* Consolidated adding / removing ClientManager IClientAPIs to two places in S... (diff)
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* Copied LocklessQueue.cs into OpenSim.Framework and added the .Count property and .Clear() method
* Changed the way the QueueEmpty callback is fired. It will be fired asynchronously as soon as an empty queue is detected (this can happen immediately following a dequeue), and will not be fired again until at least one packet is dequeued from that queue. This will give callbacks advanced notice of an empty queue and prevent callbacks from stacking up while the queue is empty * Added LLUDPClient.IsConnected checks in several places to prevent unwanted network activity after a client disconnects * Prevent LLClientView.Close() from being called twice every disconnect * Removed the packet resend limit and improved the client timeout check
Diffstat (limited to '')
-rw-r--r--OpenSim/Framework/LocklessQueue.cs130
1 files changed, 130 insertions, 0 deletions
diff --git a/OpenSim/Framework/LocklessQueue.cs b/OpenSim/Framework/LocklessQueue.cs
new file mode 100644
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1/*
2 * Copyright (c) 2009, openmetaverse.org
3 * All rights reserved.
4 *
5 * - Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * - Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 * - Neither the name of the openmetaverse.org nor the names
11 * of its contributors may be used to endorse or promote products derived from
12 * this software without specific prior written permission.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
15 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
18 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
19 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
20 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
21 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
22 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
23 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
24 * POSSIBILITY OF SUCH DAMAGE.
25 */
26
27using System;
28using System.Threading;
29
30namespace OpenSim.Framework
31{
32 public sealed class LocklessQueue<T>
33 {
34 private sealed class SingleLinkNode
35 {
36 public SingleLinkNode Next;
37 public T Item;
38 }
39
40 SingleLinkNode head;
41 SingleLinkNode tail;
42 int count;
43
44 public int Count { get { return count; } }
45
46 public LocklessQueue()
47 {
48 Init();
49 }
50
51 public void Enqueue(T item)
52 {
53 SingleLinkNode oldTail = null;
54 SingleLinkNode oldTailNext;
55
56 SingleLinkNode newNode = new SingleLinkNode();
57 newNode.Item = item;
58
59 bool newNodeWasAdded = false;
60
61 while (!newNodeWasAdded)
62 {
63 oldTail = tail;
64 oldTailNext = oldTail.Next;
65
66 if (tail == oldTail)
67 {
68 if (oldTailNext == null)
69 newNodeWasAdded = CAS(ref tail.Next, null, newNode);
70 else
71 CAS(ref tail, oldTail, oldTailNext);
72 }
73 }
74
75 CAS(ref tail, oldTail, newNode);
76 Interlocked.Increment(ref count);
77 }
78
79 public bool Dequeue(out T item)
80 {
81 item = default(T);
82 SingleLinkNode oldHead = null;
83 bool haveAdvancedHead = false;
84
85 while (!haveAdvancedHead)
86 {
87 oldHead = head;
88 SingleLinkNode oldTail = tail;
89 SingleLinkNode oldHeadNext = oldHead.Next;
90
91 if (oldHead == head)
92 {
93 if (oldHead == oldTail)
94 {
95 if (oldHeadNext == null)
96 return false;
97
98 CAS(ref tail, oldTail, oldHeadNext);
99 }
100 else
101 {
102 item = oldHeadNext.Item;
103 haveAdvancedHead = CAS(ref head, oldHead, oldHeadNext);
104 }
105 }
106 }
107
108 Interlocked.Decrement(ref count);
109 return true;
110 }
111
112 public void Clear()
113 {
114 Init();
115 }
116
117 private void Init()
118 {
119 count = 0;
120 head = tail = new SingleLinkNode();
121 }
122
123 private static bool CAS(ref SingleLinkNode location, SingleLinkNode comparand, SingleLinkNode newValue)
124 {
125 return
126 (object)comparand ==
127 (object)Interlocked.CompareExchange<SingleLinkNode>(ref location, newValue, comparand);
128 }
129 }
130} \ No newline at end of file