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-rw-r--r--OpenSim/Region/Framework/Scenes/ScenePresenceStateMachine.cs102
1 files changed, 102 insertions, 0 deletions
diff --git a/OpenSim/Region/Framework/Scenes/ScenePresenceStateMachine.cs b/OpenSim/Region/Framework/Scenes/ScenePresenceStateMachine.cs
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1/*
2 * Copyright (c) Contributors, http://opensimulator.org/
3 * See CONTRIBUTORS.TXT for a full list of copyright holders.
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 * * Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * * Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * * Neither the name of the OpenSimulator Project nor the
13 * names of its contributors may be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
17 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
20 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
23 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28using System;
29
30namespace OpenSim.Region.Framework.Scenes
31{
32 /// <summary>
33 /// The possible states that a scene presence can be in. This is currently orthagonal to whether a scene presence
34 /// is root or child.
35 /// </summary>
36 /// <remarks>
37 /// This is a state machine.
38 ///
39 /// [Entry] => Running
40 /// Running => Removing
41 /// Removing => Removed
42 ///
43 /// All other methods should only see the scene presence in running state - this is the normal operational state
44 /// Removed state occurs when the presence has been removed. This is the end state with no exit.
45 /// </remarks>
46 public enum ScenePresenceState
47 {
48 Running, // Normal operation state. The scene presence is available.
49 Removing, // The presence is in the process of being removed from the scene via Scene.RemoveClient.
50 Removed, // The presence has been removed from the scene and is effectively dead.
51 // There is no exit from this state.
52 }
53
54 internal class ScenePresenceStateMachine
55 {
56 private ScenePresence m_sp;
57 private ScenePresenceState m_state;
58
59 internal ScenePresenceStateMachine(ScenePresence sp)
60 {
61 m_sp = sp;
62 m_state = ScenePresenceState.Running;
63 }
64
65 internal ScenePresenceState GetState()
66 {
67 return m_state;
68 }
69
70 /// <summary>
71 /// Updates the state of an agent that is already in transit.
72 /// </summary>
73 /// <param name='id'></param>
74 /// <param name='newState'></param>
75 /// <returns></returns>
76 /// <exception cref='Exception'>Illegal transitions will throw an Exception</exception>
77 internal void SetState(ScenePresenceState newState)
78 {
79 bool transitionOkay = false;
80
81 lock (this)
82 {
83 if (newState == ScenePresenceState.Removing && m_state == ScenePresenceState.Running)
84 transitionOkay = true;
85 else if (newState == ScenePresenceState.Removed && m_state == ScenePresenceState.Removing)
86 transitionOkay = true;
87 }
88
89 if (!transitionOkay)
90 {
91 throw new Exception(
92 string.Format(
93 "Scene presence {0} is not allowed to move from state {1} to new state {2} in {3}",
94 m_sp.Name, m_state, newState, m_sp.Scene.Name));
95 }
96 else
97 {
98 m_state = newState;
99 }
100 }
101 }
102} \ No newline at end of file