mcs/class/corlib/System.Threading/Timer.cs

   1 //
   2 // System.Threading.Timer.cs
   3 //
   4 // Authors:
   5 //      Dick Porter (dick@ximian.com)
   6 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   7 //
   8 // (C) 2001, 2002 Ximian, Inc.  http://www.ximian.com
   9 // Copyright (C) 2004-2009 Novell, Inc (http://www.novell.com)
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System.Runtime.InteropServices;
  32 using System.Collections;
  33
  34 namespace System.Threading
  35 {
  36         [ComVisible (true)]
  37         public sealed class Timer
  38 #if MOONLIGHT
  39                 : IDisposable
  40 #else
  41                 : MarshalByRefObject, IDisposable
  42 #endif
  43         {
  44                 static readonly Scheduler scheduler = Scheduler.Instance;
  45 #region Timer instance fields
  46                 TimerCallback callback;
  47                 object state;
  48                 long due_time_ms;
  49                 long period_ms;
  50                 long next_run; // in ticks. Only 'Scheduler' can change it except for new timers without due time.
  51                 bool disposed;
  52 #endregion
  53                 public Timer (TimerCallback callback, object state, int dueTime, int period)
  54                 {
  55                         Init (callback, state, dueTime, period);
  56                 }
  57
  58                 public Timer (TimerCallback callback, object state, long dueTime, long period)
  59                 {
  60                         Init (callback, state, dueTime, period);
  61                 }
  62
  63                 public Timer (TimerCallback callback, object state, TimeSpan dueTime, TimeSpan period)
  64                 {
  65                         Init (callback, state, (long)dueTime.TotalMilliseconds, (long)period.TotalMilliseconds);
  66                 }
  67
  68                 [CLSCompliant(false)]
  69                 public Timer (TimerCallback callback, object state, uint dueTime, uint period)
  70                 {
  71                         // convert all values to long - with a special case for -1 / 0xffffffff
  72                         long d = (dueTime == UInt32.MaxValue) ? Timeout.Infinite : (long) dueTime;
  73                         long p = (period == UInt32.MaxValue) ? Timeout.Infinite : (long) period;
  74                         Init (callback, state, d, p);
  75                 }
  76
  77                 public Timer (TimerCallback callback)
  78                 {
  79                         Init (callback, this, Timeout.Infinite, Timeout.Infinite);
  80                 }
  81
  82                 void Init (TimerCallback callback, object state, long dueTime, long period)
  83                 {
  84                         if (callback == null)
  85                                 throw new ArgumentNullException ("callback");
  86
  87                         this.callback = callback;
  88                         this.state = state;
  89
  90                         Change (dueTime, period, true);
  91                 }
  92
  93                 public bool Change (int dueTime, int period)
  94                 {
  95                         return Change (dueTime, period, false);
  96                 }
  97
  98                 public bool Change (TimeSpan dueTime, TimeSpan period)
  99                 {
 100                         return Change ((long)dueTime.TotalMilliseconds, (long)period.TotalMilliseconds, false);
 101                 }
 102
 103                 [CLSCompliant(false)]
 104                 public bool Change (uint dueTime, uint period)
 105                 {
 106                         // convert all values to long - with a special case for -1 / 0xffffffff
 107                         long d = (dueTime == UInt32.MaxValue) ? Timeout.Infinite : (long) dueTime;
 108                         long p = (period == UInt32.MaxValue) ? Timeout.Infinite : (long) period;
 109                         return Change (d, p, false);
 110                 }
 111
 112                 public void Dispose ()
 113                 {
 114                         if (disposed)
 115                                 return;
 116
 117                         disposed = true;
 118                         scheduler.Remove (this);
 119                 }
 120
 121                 public bool Change (long dueTime, long period)
 122                 {
 123                         return Change (dueTime, period, false);
 124                 }
 125
 126                 const long MaxValue = UInt32.MaxValue - 1;
 127
 128                 bool Change (long dueTime, long period, bool first)
 129                 {
 130                         if (dueTime > MaxValue)
 131                                 throw new ArgumentOutOfRangeException ("dueTime", "Due time too large");
 132
 133                         if (period > MaxValue)
 134                                 throw new ArgumentOutOfRangeException ("period", "Period too large");
 135
 136                         // Timeout.Infinite == -1, so this accept everything greater than -1
 137                         if (dueTime < Timeout.Infinite)
 138                                 throw new ArgumentOutOfRangeException ("dueTime");
 139
 140                         if (period < Timeout.Infinite)
 141                                 throw new ArgumentOutOfRangeException ("period");
 142
 143                         if (disposed)
 144                                 return false;
 145
 146                         due_time_ms = dueTime;
 147                         period_ms = period;
 148                         long nr;
 149                         if (dueTime == 0) {
 150                                 nr = 0; // Due now
 151                         } else if (dueTime < 0) { // Infinite == -1
 152                                 nr = long.MaxValue;
 153                                 /* No need to call Change () */
 154                                 if (first) {
 155                                         next_run = nr;
 156                                         return true;
 157                                 }
 158                         } else {
 159                                 nr = dueTime * TimeSpan.TicksPerMillisecond + DateTime.GetTimeMonotonic ();
 160                         }
 161
 162                         scheduler.Change (this, nr);
 163                         return true;
 164                 }
 165
 166                 public bool Dispose (WaitHandle notifyObject)
 167                 {
 168                         if (notifyObject == null)
 169                                 throw new ArgumentNullException ("notifyObject");
 170                         Dispose ();
 171                         NativeEventCalls.SetEvent_internal (notifyObject.Handle);
 172                         return true;
 173                 }
 174
 175                 sealed class TimerComparer : IComparer {
 176                         public int Compare (object x, object y)
 177                         {
 178                                 Timer tx = (x as Timer);
 179                                 if (tx == null)
 180                                         return -1;
 181                                 Timer ty = (y as Timer);
 182                                 if (ty == null)
 183                                         return 1;
 184                                 long result = tx.next_run - ty.next_run;
 185                                 if (result == 0)
 186                                         return x == y ? 0 : -1;
 187                                 return result > 0 ? 1 : -1;
 188                         }
 189                 }
 190
 191                 sealed class Scheduler {
 192                         static Scheduler instance;
 193                         SortedList list;
 194                         ManualResetEvent changed;
 195
 196                         static Scheduler ()
 197                         {
 198                                 instance = new Scheduler ();
 199                         }
 200
 201                         public static Scheduler Instance {
 202                                 get { return instance; }
 203                         }
 204
 205                         private Scheduler ()
 206                         {
 207                                 changed = new ManualResetEvent (false);
 208                                 list = new SortedList (new TimerComparer (), 1024);
 209                                 Thread thread = new Thread (SchedulerThread);
 210                                 thread.IsBackground = true;
 211                                 thread.Start ();
 212                         }
 213
 214                         public void Remove (Timer timer)
 215                         {
 216                                 // We do not keep brand new items or those with no due time.
 217                                 if (timer.next_run == 0 || timer.next_run == Int64.MaxValue)
 218                                         return;
 219
 220                                 lock (this) {
 221                                         // If this is the next item due (index = 0), the scheduler will wake up and find nothing.
 222                                         // No need to Pulse ()
 223                                         InternalRemove (timer);
 224                                 }
 225                         }
 226
 227                         public void Change (Timer timer, long new_next_run)
 228                         {
 229                                 bool wake = false;
 230                                 lock (this) {
 231                                         InternalRemove (timer);
 232                                         if (new_next_run == Int64.MaxValue) {
 233                                                 timer.next_run = new_next_run;
 234                                                 return;
 235                                         }
 236
 237                                         if (!timer.disposed) {
 238                                                 // We should only change next_run after removing and before adding
 239                                                 timer.next_run = new_next_run;
 240                                                 Add (timer);
 241                                                 // If this timer is next in line, wake up the scheduler
 242                                                 wake = (list.GetByIndex (0) == timer);
 243                                         }
 244                                 }
 245                                 if (wake)
 246                                         changed.Set ();
 247                         }
 248
 249                         // lock held by caller
 250                         int FindByDueTime (long nr)
 251                         {
 252                                 int min = 0;
 253                                 int max = list.Count - 1;
 254                                 if (max < 0)
 255                                         return -1;
 256
 257                                 if (max < 20) {
 258                                         while (min <= max) {
 259                                                 Timer t = (Timer) list.GetByIndex (min);
 260                                                 if (t.next_run == nr)
 261                                                         return min;
 262                                                 if (t.next_run > nr)
 263                                                         return -1;
 264                                                 min++;
 265                                         }
 266                                         return -1;
 267                                 }
 268
 269                                 while (min <= max) {
 270                                         int half = min + ((max - min) >> 1);
 271                                         Timer t = (Timer) list.GetByIndex (half);
 272                                         if (nr == t.next_run)
 273                                                 return half;
 274                                         if (nr > t.next_run)
 275                                                 min = half + 1;
 276                                         else
 277                                                 max = half - 1;
 278                                 }
 279
 280                                 return -1;
 281                         }
 282
 283                         // This should be the only caller to list.Add!
 284                         void Add (Timer timer)
 285                         {
 286                                 // Make sure there are no collisions (10000 ticks == 1ms, so we should be safe here)
 287                                 // Do not use list.IndexOfKey here. See bug #648130
 288                                 int idx = FindByDueTime (timer.next_run);
 289                                 if (idx != -1) {
 290                                         bool up = (Int64.MaxValue - timer.next_run) > 20000 ? true : false;
 291                                         while (true) {
 292                                                 idx++;
 293                                                 if (up)
 294                                                         timer.next_run++;
 295                                                 else
 296                                                         timer.next_run--;
 297
 298                                                 if (idx >= list.Count)
 299                                                         break;
 300                                                 Timer t2 = (Timer) list.GetByIndex (idx);
 301                                                 if (t2.next_run != timer.next_run)
 302                                                         break;
 303                                         }
 304                                 }
 305                                 list.Add (timer, timer);
 306                                 //PrintList ();
 307                         }
 308
 309                         int InternalRemove (Timer timer)
 310                         {
 311                                 int idx = list.IndexOfKey (timer);
 312                                 if (idx >= 0)
 313                                         list.RemoveAt (idx);
 314                                 return idx;
 315                         }
 316
 317                         static WaitCallback TimerCaller = new WaitCallback (TimerCB);
 318                         static void TimerCB (object o)
 319                         {
 320                                 Timer timer = (Timer) o;
 321                                 try {
 322                                         timer.callback (timer.state);
 323                                 } catch {}
 324                         }
 325
 326                         void SchedulerThread ()
 327                         {
 328                                 Thread.CurrentThread.Name = "Timer-Scheduler";
 329                                 ArrayList new_time = new ArrayList (512);
 330                                 while (true) {
 331                                         int ms_wait = -1;
 332                                         long ticks = DateTime.GetTimeMonotonic ();
 333                                         lock (this) {
 334                                                 changed.Reset ();
 335                                                 //PrintList ();
 336                                                 int i;
 337                                                 int count = list.Count;
 338                                                 for (i = 0; i < count; i++) {
 339                                                         Timer timer = (Timer) list.GetByIndex (i);
 340                                                         if (timer.next_run > ticks)
 341                                                                 break;
 342
 343                                                         list.RemoveAt (i);
 344                                                         count--;
 345                                                         i--;
 346 #if MOONLIGHT
 347                                                         ThreadPool.QueueUserWorkItem (TimerCaller, timer);
 348 #else
 349                                                         ThreadPool.UnsafeQueueUserWorkItem (TimerCaller, timer);
 350 #endif
 351                                                         long period = timer.period_ms;
 352                                                         long due_time = timer.due_time_ms;
 353                                                         bool no_more = (period == -1 || ((period == 0 || period == Timeout.Infinite) && due_time != Timeout.Infinite));
 354                                                         if (no_more) {
 355                                                                 timer.next_run = Int64.MaxValue;
 356                                                         } else {
 357                                                                 timer.next_run = DateTime.GetTimeMonotonic () + TimeSpan.TicksPerMillisecond * timer.period_ms;
 358                                                                 new_time.Add (timer);
 359                                                         }
 360                                                 }
 361
 362                                                 // Reschedule timers with a new due time
 363                                                 count = new_time.Count;
 364                                                 for (i = 0; i < count; i++) {
 365                                                         Timer timer = (Timer) new_time [i];
 366                                                         Add (timer);
 367                                                 }
 368                                                 new_time.Clear ();
 369                                                 ShrinkIfNeeded (new_time, 512);
 370
 371                                                 // Shrink the list
 372                                                 int capacity = list.Capacity;
 373                                                 count = list.Count;
 374                                                 if (capacity > 1024 && count > 0 && (capacity / count) > 3)
 375                                                         list.Capacity = count * 2;
 376
 377                                                 long min_next_run = Int64.MaxValue;
 378                                                 if (list.Count > 0)
 379                                                         min_next_run = ((Timer) list.GetByIndex (0)).next_run;
 380
 381                                                 //PrintList ();
 382                                                 ms_wait = -1;
 383                                                 if (min_next_run != Int64.MaxValue) {
 384                                                         long diff = (min_next_run - DateTime.GetTimeMonotonic ())  / TimeSpan.TicksPerMillisecond;
 385                                                         if (diff > Int32.MaxValue)
 386                                                                 ms_wait = Int32.MaxValue - 1;
 387                                                         else {
 388                                                                 ms_wait = (int)(diff);
 389                                                                 if (ms_wait < 0)
 390                                                                         ms_wait = 0;
 391                                                         }
 392                                                 }
 393                                         }
 394                                         // Wait until due time or a timer is changed and moves from/to the first place in the list.
 395                                         changed.WaitOne (ms_wait);
 396                                 }
 397                         }
 398
 399                         void ShrinkIfNeeded (ArrayList list, int initial)
 400                         {
 401                                 int capacity = list.Capacity;
 402                                 int count = list.Count;
 403                                 if (capacity > initial && count > 0 && (capacity / count) > 3)
 404                                         list.Capacity = count * 2;
 405                         }
 406
 407                         /*
 408                         void PrintList ()
 409                         {
 410                                 Console.WriteLine ("BEGIN--");
 411                                 for (int i = 0; i < list.Count; i++) {
 412                                         Timer timer = (Timer) list.GetByIndex (i);
 413                                         Console.WriteLine ("{0}: {1}", i, timer.next_run);
 414                                 }
 415                                 Console.WriteLine ("END----");
 416                         }
 417                         */
 418                 }
 419         }
 420 }
 421