AsyncFlowControl.cs :  » 2.6.4-mono-.net-core » System.Threading » System » Threading » C# / CSharp Open Source

//
// System.Threading.AsyncFlowControl.cs
//
// Author:
//  Sebastien Pouliot  <sebastien@ximian.com>
//
// Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System.Globalization;
using System.Runtime.InteropServices;
using System.Security;

namespace System.Threading{

  internal enum AsyncFlowControlType {
    None,
    Execution,
    Security
  }

  public struct AsyncFlowControl : IDisposable {
    private Thread _t;
    private AsyncFlowControlType _type;

    internal AsyncFlowControl (Thread t, AsyncFlowControlType type)
    {
      _t = t;
      _type = type;
    }

    public void Undo ()
    {
      if (_t == null) {
        throw new InvalidOperationException (Locale.GetText (
          "Can only be called once."));
      }
      switch (_type) {
      case AsyncFlowControlType.Execution:
        ExecutionContext.RestoreFlow ();
        break;
      case AsyncFlowControlType.Security:
        SecurityContext.RestoreFlow ();
        break;
      }
      _t = null;
    }

    void IDisposable.Dispose () 
    {
      if (_t != null) {
        Undo ();
        _t = null;
        _type = AsyncFlowControlType.None;
      }
    }

    public override int GetHashCode ()
    {
      return(base.GetHashCode ());
    }
    
    public override bool Equals (object obj)
    {
      if (!(obj is AsyncFlowControl)) {
        return(false);
      }
      
      return(obj.Equals (this));
    }
    
    public bool Equals (AsyncFlowControl obj)
    {
      if (this._t == obj._t &&
          this._type == obj._type) {
        return(true);
      } else {
        return(false);
      }
    }

    public static bool operator == (AsyncFlowControl a, AsyncFlowControl b)
    {
      return a.Equals (b);
    }

    public static bool operator != (AsyncFlowControl a, AsyncFlowControl b)
    {
      return !a.Equals (b);
    }
  }
}