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diff --git a/OpenSim/Framework/ACL.cs b/OpenSim/Framework/ACL.cs
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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 OpenSim 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;
+
+namespace OpenSim.Framework
+{
+    // ACL Class
+    // Modelled after the structure of the Zend ACL Framework Library
+    // with one key difference - the tree will search for all matching
+    // permissions rather than just the first. Deny permissions will
+    // override all others.
+
+    #region ACL Core Class
+
+    /// <summary>
+    /// Access Control List Engine
+    /// </summary>
+    public class ACL
+    {
+        private Dictionary<string, Role> Roles = new Dictionary<string, Role>();
+        private Dictionary<string, Resource> Resources = new Dictionary<string, Resource>();
+
+        public ACL AddRole(Role role)
+        {
+            if (Roles.ContainsKey(role.Name))
+                throw new AlreadyContainsRoleException(role);
+
+            Roles.Add(role.Name, role);
+
+            return this;
+        }
+
+        public ACL AddResource(Resource resource)
+        {
+            Resources.Add(resource.Name, resource);
+
+            return this;
+        }
+
+        public Permission HasPermission(string role, string resource)
+        {
+            if (!Roles.ContainsKey(role))
+                throw new KeyNotFoundException();
+
+            if (!Resources.ContainsKey(resource))
+                throw new KeyNotFoundException();
+
+            return Roles[role].RequestPermission(resource);
+        }
+
+        public ACL GrantPermission(string role, string resource)
+        {
+            if (!Roles.ContainsKey(role))
+                throw new KeyNotFoundException();
+
+            if (!Resources.ContainsKey(resource))
+                throw new KeyNotFoundException();
+
+            Roles[role].GivePermission(resource, Permission.Allow);
+
+            return this;
+        }
+
+        public ACL DenyPermission(string role, string resource)
+        {
+            if (!Roles.ContainsKey(role))
+                throw new KeyNotFoundException();
+
+            if (!Resources.ContainsKey(resource))
+                throw new KeyNotFoundException();
+
+            Roles[role].GivePermission(resource, Permission.Deny);
+
+            return this;
+        }
+
+        public ACL ResetPermission(string role, string resource)
+        {
+            if (!Roles.ContainsKey(role))
+                throw new KeyNotFoundException();
+
+            if (!Resources.ContainsKey(resource))
+                throw new KeyNotFoundException();
+
+            Roles[role].GivePermission(resource, Permission.None);
+
+            return this;
+        }
+    }
+
+    #endregion
+
+    #region Exceptions
+
+    /// <summary>
+    /// Thrown when an ACL attempts to add a duplicate role.
+    /// </summary>
+    public class AlreadyContainsRoleException : Exception
+    {
+        protected Role m_role;
+
+        public Role ErrorRole
+        {
+            get { return m_role; }
+        }
+
+        public AlreadyContainsRoleException(Role role)
+        {
+            m_role = role;
+        }
+
+        public override string ToString()
+        {
+            return "This ACL already contains a role called '" + m_role.Name + "'.";
+        }
+    }
+
+    #endregion
+
+    #region Roles and Resources
+
+    /// <summary>
+    /// Does this Role have permission to access a specified Resource?
+    /// </summary>
+    public enum Permission
+    {
+        Deny,
+        None,
+        Allow
+    } ;
+
+    /// <summary>
+    /// A role class, for use with Users or Groups
+    /// </summary>
+    public class Role
+    {
+        private string m_name;
+        private Role[] m_parents;
+        private Dictionary<string, Permission> m_resources = new Dictionary<string, Permission>();
+
+        public string Name
+        {
+            get { return m_name; }
+        }
+
+        public Permission RequestPermission(string resource)
+        {
+            return RequestPermission(resource, Permission.None);
+        }
+
+        public Permission RequestPermission(string resource, Permission current)
+        {
+            // Deny permissions always override any others
+            if (current == Permission.Deny)
+                return current;
+
+            Permission temp = Permission.None;
+
+            // Pickup non-None permissions
+            if (m_resources.ContainsKey(resource) && m_resources[resource] != Permission.None)
+                temp = m_resources[resource];
+
+            if (m_parents != null)
+            {
+                foreach (Role parent in m_parents)
+                {
+                    temp = parent.RequestPermission(resource, temp);
+                }
+            }
+
+            return temp;
+        }
+
+        public void GivePermission(string resource, Permission perm)
+        {
+            m_resources[resource] = perm;
+        }
+
+        public Role(string name)
+        {
+            m_name = name;
+            m_parents = null;
+        }
+
+        public Role(string name, Role[] parents)
+        {
+            m_name = name;
+            m_parents = parents;
+        }
+    }
+
+    public class Resource
+    {
+        private string m_name;
+
+        public string Name
+        {
+            get { return m_name; }
+        }
+
+        public Resource(string name)
+        {
+            m_name = name;
+        }
+    }
+
+    #endregion
+
+    #region Tests
+
+    internal class ACLTester
+    {
+        public ACLTester()
+        {
+            ACL acl = new ACL();
+
+            Role Guests = new Role("Guests");
+            acl.AddRole(Guests);
+
+            Role[] parents = new Role[0];
+            parents[0] = Guests;
+
+            Role JoeGuest = new Role("JoeGuest", parents);
+            acl.AddRole(JoeGuest);
+
+            Resource CanBuild = new Resource("CanBuild");
+            acl.AddResource(CanBuild);
+
+
+            acl.GrantPermission("Guests", "CanBuild");
+
+            acl.HasPermission("JoeGuest", "CanBuild");
+        }
+    }
+
+    #endregion
+}
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