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Viewing changes to external/nrefactory/ICSharpCode.NRefactory/Utils/BusyManager.cs

  • Committer: Package Import Robot
  • Author(s): Jo Shields
  • Date: 2013-05-12 09:46:03 UTC
  • mto: This revision was merged to the branch mainline in revision 29.
  • Revision ID: package-import@ubuntu.com-20130512094603-mad323bzcxvmcam0
Tags: upstream-4.0.5+dfsg
Import upstream version 4.0.5+dfsg

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external/nrefactory/ICSharpCode.NRefactory/Utils/BusyManager.cs
 
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// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop Team
 
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// 
 
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// Permission is hereby granted, free of charge, to any person obtaining a copy of this
 
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// software and associated documentation files (the "Software"), to deal in the Software
 
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// without restriction, including without limitation the rights to use, copy, modify, merge,
 
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// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
 
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// to whom the Software is furnished to do so, subject to the following conditions:
 
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// 
 
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// The above copyright notice and this permission notice shall be included in all copies or
 
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// substantial portions of the Software.
 
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// 
 
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 
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// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 
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// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
 
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// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 
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// DEALINGS IN THE SOFTWARE.
 
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using System;
 
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using System.Collections.Generic;
 
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namespace ICSharpCode.NRefactory.Utils
 
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{
 
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        /// <summary>
 
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        /// This class is used to prevent stack overflows by representing a 'busy' flag
 
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        /// that prevents reentrance when another call is running.
 
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        /// However, using a simple 'bool busy' is not thread-safe, so we use a
 
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        /// thread-static BusyManager.
 
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        /// </summary>
 
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        public static class BusyManager
 
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        {
 
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                [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1815:OverrideEqualsAndOperatorEqualsOnValueTypes")]
 
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                [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1034:NestedTypesShouldNotBeVisible",
 
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                                                                 Justification = "Should always be used with 'var'")]
 
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                public struct BusyLock : IDisposable
 
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                {
 
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                        public static readonly BusyLock Failed = new BusyLock(null);
 
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                        readonly List<object> objectList;
 
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                        internal BusyLock(List<object> objectList)
 
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                        {
 
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                                this.objectList = objectList;
 
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                        }
 
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                        public bool Success {
 
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                                get { return objectList != null; }
 
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                        }
 
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                        public void Dispose()
 
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                        {
 
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                                if (objectList != null) {
 
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                                        objectList.RemoveAt(objectList.Count - 1);
 
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                                }
 
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                        }
 
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                }
 
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                [ThreadStatic] static List<object> _activeObjects;
 
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                public static BusyLock Enter(object obj)
 
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                {
 
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                        List<object> activeObjects = _activeObjects;
 
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                        if (activeObjects == null)
 
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                                activeObjects = _activeObjects = new List<object>();
 
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                        for (int i = 0; i < activeObjects.Count; i++) {
 
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                                if (activeObjects[i] == obj)
 
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                                        return BusyLock.Failed;
 
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                        }
 
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                        activeObjects.Add(obj);
 
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                        return new BusyLock(activeObjects);
 
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                }
 
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        }
 
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}