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

//
// System.Timers.Timer
//
// Authors:
//  Gonzalo Paniagua Javier (gonzalo@ximian.com)
//
// (C) 2002 Ximian, Inc (http://www.ximian.com)
// Copyright (C) 2005 Novell, Inc (http://www.novell.com)
//
// The docs talk about server timers and such...

//
// 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.ComponentModel;
using System.Threading;

namespace System.Timers{
#if MOONLIGHT
  internal class Timer {
#else
  [DefaultEventAttribute("Elapsed")]
  [DefaultProperty("Interval")]
  public class Timer : Component, ISupportInitialize {
#endif
    double interval;
    bool autoReset;
    System.Threading.Timer timer;
    object _lock = new object ();
    ISynchronizeInvoke so;

    [Category("Behavior")]
    [TimersDescription("Occurs when the Interval has elapsed.")]
    public event ElapsedEventHandler Elapsed;

    public Timer () : this (100)
    {
    }

    public Timer (double interval)
    {
      // MSBUG: https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=296761
      if (interval > 0x7FFFFFFF)
        throw new ArgumentException ("Invalid value: " + interval, "interval");

      autoReset = true;
      Interval = interval;
    }

    [Category("Behavior")]
    [DefaultValue(true)]
    [TimersDescription("Indicates whether the timer will be restarted when it is enabled.")]
    public bool AutoReset
    {
      get { return autoReset; }
      set { autoReset = value; }
    }

    [Category("Behavior")]
    [DefaultValue(false)]
    [TimersDescription("Indicates whether the timer is enabled to fire events at a defined interval.")]
    public bool Enabled
    {
      get {
        lock (_lock)
          return timer != null;
      }
      set {
        lock (_lock) {
          bool enabled = timer != null;
          if (enabled == value)
            return;

          if (value) {
            timer = new System.Threading.Timer (Callback, this, (int)interval, autoReset ? (int)interval: 0);
          } else {
            timer.Dispose ();
            timer = null;
          }
        }
      }
    }

    [Category("Behavior")]
    [DefaultValue(100)]
    [RecommendedAsConfigurable(true)]
    [TimersDescription( "The number of milliseconds between timer events.")]
    public double Interval
    {
      get { return interval; }
      set { 
        // The doc says 'less than 0', but 0 also throws the exception
        if (value <= 0)
          throw new ArgumentException ("Invalid value: " + value);

        lock (_lock) {
          interval = value;
          if (timer != null)
            timer.Change ((int)interval, autoReset? (int)interval: 0);
        }
      }
    }

#if !MOONLIGHT
    public override ISite Site
    {
      get { return base.Site; }
      set { base.Site = value; }
    }
#endif
    [DefaultValue(null)]
    [TimersDescriptionAttribute("The object used to marshal the event handler calls issued " +
              "when an interval has elapsed.")]
    [Browsable (false)]
    public ISynchronizeInvoke SynchronizingObject
    {
      get { return so; }
      set { so = value; }
    }

    public void BeginInit ()
    {
      // Nothing to do
    }

    public void Close ()
    {
      Enabled = false;
    }

    public void EndInit ()
    {
      // Nothing to do
    }

    public void Start ()
    {
      Enabled = true;
    }

    public void Stop ()
    {
      Enabled = false;
    }

#if MOONLIGHT
    protected void Dispose (bool disposing)
    {
      Close ();
    }
#else
    protected override void Dispose (bool disposing)
    {
      Close ();
      base.Dispose (disposing);
    }
#endif

    static void Callback (object state)
    {
      Timer timer = (Timer) state;
      if (timer.Enabled == false)
        return;
      ElapsedEventHandler events = timer.Elapsed;
      if (!timer.autoReset)
        timer.Enabled = false;
      if (events == null)
        return;

      ElapsedEventArgs arg = new ElapsedEventArgs (DateTime.Now);

      if (timer.so != null && timer.so.InvokeRequired) {
        timer.so.BeginInvoke (events, new object [2] {timer, arg});
      } else {
        try {
          events (timer, arg);
        } catch {
        }
      }
    }

  }
}