51 lines
1.7 KiB
C#
51 lines
1.7 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Diagnostics.CodeAnalysis;
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using System.Linq;
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namespace Unity.CodeEditor.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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internal static class BusyManager
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{
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[SuppressMessage("Microsoft.Performance", "CA1815:OverrideEqualsAndOperatorEqualsOnValueTypes")]
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[SuppressMessage("Microsoft.Design", "CA1034:NestedTypesShouldNotBeVisible",
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Justification = "Should always be used with 'var'")]
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internal struct BusyLock : IDisposable
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{
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internal static readonly BusyLock Failed = new BusyLock(null);
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private readonly List<object> _objectList;
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internal BusyLock(List<object> objectList)
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{
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_objectList = objectList;
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}
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internal bool Success => _objectList != null;
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public void Dispose()
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{
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_objectList?.RemoveAt(_objectList.Count - 1);
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}
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}
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[ThreadStatic] private static List<object> _activeObjects;
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internal static BusyLock Enter(object obj)
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{
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var activeObjects = _activeObjects ?? (_activeObjects = new List<object>());
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if (activeObjects.Any(t => t == obj))
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{
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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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} |