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

#if NET_4_0 || BOOTSTRAP_NET_4_0
// 
// Barrier.cs
//  
// Author:
//       Jrmie "Garuma" Laval <jeremie.laval@gmail.com>
// 
// Copyright (c) 2009 Jrmie "Garuma" Laval
// 
// 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;

namespace System.Threading{
  public class Barrier : IDisposable
  {
    const int MaxParticipants = 32767;
    Action<Barrier> postPhaseAction;
    
    int participants;
    CountdownEvent cntd;
    AtomicBoolean cleaned = new AtomicBoolean ();
    long phase;
    
    public Barrier (int participants) : this (participants, null)
    {
    }
    
    public Barrier (int participants, Action<Barrier> postPhaseAction)
    {
      if (participants < 0 || participants > MaxParticipants)
        throw new ArgumentOutOfRangeException ("participants");
      
      this.participants = participants;
      this.postPhaseAction = postPhaseAction;
      
      InitCountdownEvent ();
    }

    public void Dispose ()
    {
      Dispose (true);
    }

    protected virtual void Dispose (bool disposing)
    {
      if (disposing){
        if (cntd != null){
          cntd.Dispose ();
          cntd = null;
        }
        cleaned = null;
        postPhaseAction = null;
      }
    }
      
    void InitCountdownEvent ()
    {
      cleaned = new AtomicBoolean ();
      cntd = new CountdownEvent (participants);
    }
    
    public long AddParticipant ()
    {
      return AddParticipants (1);
    }

    static Exception GetDisposed ()
    {
      return new ObjectDisposedException ("Barrier");
    }
    
    public long AddParticipants (int participantCount)
    {
      if (cleaned == null)
        throw GetDisposed ();
      
      if (participantCount < 0)
        throw new InvalidOperationException ();
      
      // Basically, we try to add ourselves and return
      // the phase. If the call return false, we repeatdly try
      // to add ourselves for the next phase
      do {
        if (cntd.TryAddCount (participantCount)) {
          Interlocked.Add (ref participants, participantCount);
          return phase;
        }
      } while (true);
    }
    
    public void RemoveParticipant ()
    {
      RemoveParticipants (1);
    }
    
    public void RemoveParticipants (int participantCount)
    {
      if (cleaned == null)
        throw GetDisposed ();
      if (participantCount < 0)
        throw new ArgumentOutOfRangeException ("participantCount");
      
      if (cntd.Signal (participantCount))
        PostPhaseAction (cleaned);

      Interlocked.Add (ref participants, -participantCount);
    }
    
    public void SignalAndWait ()
    {
      if (cleaned == null)
        throw GetDisposed ();
      SignalAndWait ((c) => { c.Wait (); return true; });
    }
    
    public bool SignalAndWait (int millisecondTimeout)
    {
      if (cleaned == null)
        throw GetDisposed ();
      return SignalAndWait ((c) => c.Wait (millisecondTimeout));
    }
    
    public bool SignalAndWait (TimeSpan ts)
    {
      if (cleaned == null)
        throw GetDisposed ();
      return SignalAndWait ((c) => c.Wait (ts));
    }
    
    public bool SignalAndWait (int millisecondTimeout, CancellationToken token)
    {
      if (cleaned == null)
        throw GetDisposed ();
      return SignalAndWait ((c) => c.Wait (millisecondTimeout, token));
    }
    
    public bool SignalAndWait (TimeSpan ts, CancellationToken token)
    {
      if (cleaned == null)
        throw GetDisposed ();
      return SignalAndWait ((c) => c.Wait (ts, token));
    }
    
    bool SignalAndWait (Func<CountdownEvent, bool> associate)
    {
      bool result;
      AtomicBoolean cl = cleaned;
      CountdownEvent temp = cntd;
      
      if (!temp.Signal ()) {
        result = Wait (associate, temp, cl);
      } else {
        result = true;
        PostPhaseAction (cl);
      }
      
      return result;
    }
    
    bool Wait (Func<CountdownEvent, bool> associate, CountdownEvent temp, AtomicBoolean cl)
    {
      if (!associate (temp))
        return false;
      
      SpinWait sw = new SpinWait ();
      while (!cl.Value)
        sw.SpinOnce ();
      
      return true;
    }
    
    void PostPhaseAction (AtomicBoolean cl)
    {
      if (postPhaseAction != null)
        postPhaseAction (this);
      
      InitCountdownEvent ();
      
      cl.Value = true;
      phase++;
    }
    
    public long CurrentPhaseNumber {
      get {
        return phase;
      }
    }
    
    public int ParticipantCount  {
      get {
        return participants;
      }
    }
  }
}
#endif