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                 : MarshalByRefObject, IDisposable
  39         {
  40                 static readonly Scheduler scheduler = Scheduler.Instance;
  41 #region Timer instance fields
  42                 TimerCallback callback;
  43                 object state;
  44                 long due_time_ms;
  45                 long period_ms;
  46                 long next_run; // in ticks. Only 'Scheduler' can change it except for new timers without due time.
  47                 bool disposed;
  48 #endregion
  49                 public Timer (TimerCallback callback, object state, int dueTime, int period)
  50                 {
  51                         Init (callback, state, dueTime, period);
  52                 }
  53
  54                 public Timer (TimerCallback callback, object state, long dueTime, long period)
  55                 {
  56                         Init (callback, state, dueTime, period);
  57                 }
  58
  59                 public Timer (TimerCallback callback, object state, TimeSpan dueTime, TimeSpan period)
  60                 {
  61                         Init (callback, state, (long)dueTime.TotalMilliseconds, (long)period.TotalMilliseconds);
  62                 }
  63
  64                 [CLSCompliant(false)]
  65                 public Timer (TimerCallback callback, object state, uint dueTime, uint period)
  66                 {
  67                         // convert all values to long - with a special case for -1 / 0xffffffff
  68                         long d = (dueTime == UInt32.MaxValue) ? Timeout.Infinite : (long) dueTime;
  69                         long p = (period == UInt32.MaxValue) ? Timeout.Infinite : (long) period;
  70                         Init (callback, state, d, p);
  71                 }
  72
  73                 public Timer (TimerCallback callback)
  74                 {
  75                         Init (callback, this, Timeout.Infinite, Timeout.Infinite);
  76                 }
  77
  78                 void Init (TimerCallback callback, object state, long dueTime, long period)
  79                 {
  80                         if (callback == null)
  81                                 throw new ArgumentNullException ("callback");
  82
  83                         this.callback = callback;
  84                         this.state = state;
  85
  86                         Change (dueTime, period, true);
  87                 }
  88
  89                 public bool Change (int dueTime, int period)
  90                 {
  91                         return Change (dueTime, period, false);
  92                 }
  93
  94                 public bool Change (TimeSpan dueTime, TimeSpan period)
  95                 {
  96                         return Change ((long)dueTime.TotalMilliseconds, (long)period.TotalMilliseconds, false);
  97                 }
  98
  99                 [CLSCompliant(false)]
 100                 public bool Change (uint dueTime, uint period)
 101                 {
 102                         // convert all values to long - with a special case for -1 / 0xffffffff
 103                         long d = (dueTime == UInt32.MaxValue) ? Timeout.Infinite : (long) dueTime;
 104                         long p = (period == UInt32.MaxValue) ? Timeout.Infinite : (long) period;
 105                         return Change (d, p, false);
 106                 }
 107
 108                 public void Dispose ()
 109                 {
 110                         if (disposed)
 111                                 return;
 112
 113                         disposed = true;
 114                         scheduler.Remove (this);
 115                 }
 116
 117                 public bool Change (long dueTime, long period)
 118                 {
 119                         return Change (dueTime, period, false);
 120                 }
 121
 122                 const long MaxValue = UInt32.MaxValue - 1;
 123
 124                 bool Change (long dueTime, long period, bool first)
 125                 {
 126                         if (dueTime > MaxValue)
 127                                 throw new ArgumentOutOfRangeException ("dueTime", "Due time too large");
 128
 129                         if (period > MaxValue)
 130                                 throw new ArgumentOutOfRangeException ("period", "Period too large");
 131
 132                         // Timeout.Infinite == -1, so this accept everything greater than -1
 133                         if (dueTime < Timeout.Infinite)
 134                                 throw new ArgumentOutOfRangeException ("dueTime");
 135
 136                         if (period < Timeout.Infinite)
 137                                 throw new ArgumentOutOfRangeException ("period");
 138
 139                         if (disposed)
 140                                 return false;
 141
 142                         due_time_ms = dueTime;
 143                         period_ms = period;
 144                         long nr;
 145                         if (dueTime == 0) {
 146                                 nr = 0; // Due now
 147                         } else if (dueTime < 0) { // Infinite == -1
 148                                 nr = long.MaxValue;
 149                                 /* No need to call Change () */
 150                                 if (first) {
 151                                         next_run = nr;
 152                                         return true;
 153                                 }
 154                         } else {
 155                                 nr = dueTime * TimeSpan.TicksPerMillisecond + DateTime.GetTimeMonotonic ();
 156                         }
 157
 158                         scheduler.Change (this, nr);
 159                         return true;
 160                 }
 161
 162                 public bool Dispose (WaitHandle notifyObject)
 163                 {
 164                         if (notifyObject == null)
 165                                 throw new ArgumentNullException ("notifyObject");
 166                         Dispose ();
 167                         NativeEventCalls.SetEvent_internal (notifyObject.Handle);
 168                         return true;
 169                 }
 170
 171                 sealed class TimerComparer : IComparer {
 172                         public int Compare (object x, object y)
 173                         {
 174                                 Timer tx = (x as Timer);
 175                                 if (tx == null)
 176                                         return -1;
 177                                 Timer ty = (y as Timer);
 178                                 if (ty == null)
 179                                         return 1;
 180                                 long result = tx.next_run - ty.next_run;
 181                                 if (result == 0)
 182                                         return x == y ? 0 : -1;
 183                                 return result > 0 ? 1 : -1;
 184                         }
 185                 }
 186
 187                 sealed class Scheduler {
 188                         static Scheduler instance;
 189                         SortedList list;
 190                         ManualResetEvent changed;
 191
 192                         static Scheduler ()
 193                         {
 194                                 instance = new Scheduler ();
 195                         }
 196
 197                         public static Scheduler Instance {
 198                                 get { return instance; }
 199                         }
 200
 201                         private Scheduler ()
 202                         {
 203                                 changed = new ManualResetEvent (false);
 204                                 list = new SortedList (new TimerComparer (), 1024);
 205                                 Thread thread = new Thread (SchedulerThread);
 206                                 thread.IsBackground = true;
 207                                 thread.Start ();
 208                         }
 209
 210                         public void Remove (Timer timer)
 211                         {
 212                                 // We do not keep brand new items or those with no due time.
 213                                 if (timer.next_run == 0 || timer.next_run == Int64.MaxValue)
 214                                         return;
 215
 216                                 lock (this) {
 217                                         // If this is the next item due (index = 0), the scheduler will wake up and find nothing.
 218                                         // No need to Pulse ()
 219                                         InternalRemove (timer);
 220                                 }
 221                         }
 222
 223                         public void Change (Timer timer, long new_next_run)
 224                         {
 225                                 bool wake = false;
 226                                 lock (this) {
 227                                         InternalRemove (timer);
 228                                         if (new_next_run == Int64.MaxValue) {
 229                                                 timer.next_run = new_next_run;
 230                                                 return;
 231                                         }
 232
 233                                         if (!timer.disposed) {
 234                                                 // We should only change next_run after removing and before adding
 235                                                 timer.next_run = new_next_run;
 236                                                 Add (timer);
 237                                                 // If this timer is next in line, wake up the scheduler
 238                                                 wake = (list.GetByIndex (0) == timer);
 239                                         }
 240                                 }
 241                                 if (wake)
 242                                         changed.Set ();
 243                         }
 244
 245                         // lock held by caller
 246                         int FindByDueTime (long nr)
 247                         {
 248                                 int min = 0;
 249                                 int max = list.Count - 1;
 250                                 if (max < 0)
 251                                         return -1;
 252
 253                                 if (max < 20) {
 254                                         while (min <= max) {
 255                                                 Timer t = (Timer) list.GetByIndex (min);
 256                                                 if (t.next_run == nr)
 257                                                         return min;
 258                                                 if (t.next_run > nr)
 259                                                         return -1;
 260                                                 min++;
 261                                         }
 262                                         return -1;
 263                                 }
 264
 265                                 while (min <= max) {
 266                                         int half = min + ((max - min) >> 1);
 267                                         Timer t = (Timer) list.GetByIndex (half);
 268                                         if (nr == t.next_run)
 269                                                 return half;
 270                                         if (nr > t.next_run)
 271                                                 min = half + 1;
 272                                         else
 273                                                 max = half - 1;
 274                                 }
 275
 276                                 return -1;
 277                         }
 278
 279                         // This should be the only caller to list.Add!
 280                         void Add (Timer timer)
 281                         {
 282                                 // Make sure there are no collisions (10000 ticks == 1ms, so we should be safe here)
 283                                 // Do not use list.IndexOfKey here. See bug #648130
 284                                 int idx = FindByDueTime (timer.next_run);
 285                                 if (idx != -1) {
 286                                         bool up = (Int64.MaxValue - timer.next_run) > 20000 ? true : false;
 287                                         while (true) {
 288                                                 idx++;
 289                                                 if (up)
 290                                                         timer.next_run++;
 291                                                 else
 292                                                         timer.next_run--;
 293
 294                                                 if (idx >= list.Count)
 295                                                         break;
 296                                                 Timer t2 = (Timer) list.GetByIndex (idx);
 297                                                 if (t2.next_run != timer.next_run)
 298                                                         break;
 299                                         }
 300                                 }
 301                                 list.Add (timer, timer);
 302                                 //PrintList ();
 303                         }
 304
 305                         int InternalRemove (Timer timer)
 306                         {
 307                                 int idx = list.IndexOfKey (timer);
 308                                 if (idx >= 0)
 309                                         list.RemoveAt (idx);
 310                                 return idx;
 311                         }
 312
 313                         static WaitCallback TimerCaller = new WaitCallback (TimerCB);
 314                         static void TimerCB (object o)
 315                         {
 316                                 Timer timer = (Timer) o;
 317                                 try {
 318                                         timer.callback (timer.state);
 319                                 } catch {}
 320                         }
 321
 322                         void SchedulerThread ()
 323                         {
 324                                 Thread.CurrentThread.Name = "Timer-Scheduler";
 325                                 ArrayList new_time = new ArrayList (512);
 326                                 while (true) {
 327                                         int ms_wait = -1;
 328                                         long ticks = DateTime.GetTimeMonotonic ();
 329                                         lock (this) {
 330                                                 changed.Reset ();
 331                                                 //PrintList ();
 332                                                 int i;
 333                                                 int count = list.Count;
 334                                                 for (i = 0; i < count; i++) {
 335                                                         Timer timer = (Timer) list.GetByIndex (i);
 336                                                         if (timer.next_run > ticks)
 337                                                                 break;
 338
 339                                                         list.RemoveAt (i);
 340                                                         count--;
 341                                                         i--;
 342                                                         ThreadPool.UnsafeQueueUserWorkItem (TimerCaller, timer);
 343                                                         long period = timer.period_ms;
 344                                                         long due_time = timer.due_time_ms;
 345                                                         bool no_more = (period == -1 || ((period == 0 || period == Timeout.Infinite) && due_time != Timeout.Infinite));
 346                                                         if (no_more) {
 347                                                                 timer.next_run = Int64.MaxValue;
 348                                                         } else {
 349                                                                 timer.next_run = DateTime.GetTimeMonotonic () + TimeSpan.TicksPerMillisecond * timer.period_ms;
 350                                                                 new_time.Add (timer);
 351                                                         }
 352                                                 }
 353
 354                                                 // Reschedule timers with a new due time
 355                                                 count = new_time.Count;
 356                                                 for (i = 0; i < count; i++) {
 357                                                         Timer timer = (Timer) new_time [i];
 358                                                         Add (timer);
 359                                                 }
 360                                                 new_time.Clear ();
 361                                                 ShrinkIfNeeded (new_time, 512);
 362
 363                                                 // Shrink the list
 364                                                 int capacity = list.Capacity;
 365                                                 count = list.Count;
 366                                                 if (capacity > 1024 && count > 0 && (capacity / count) > 3)
 367                                                         list.Capacity = count * 2;
 368
 369                                                 long min_next_run = Int64.MaxValue;
 370                                                 if (list.Count > 0)
 371                                                         min_next_run = ((Timer) list.GetByIndex (0)).next_run;
 372
 373                                                 //PrintList ();
 374                                                 ms_wait = -1;
 375                                                 if (min_next_run != Int64.MaxValue) {
 376                                                         long diff = (min_next_run - DateTime.GetTimeMonotonic ())  / TimeSpan.TicksPerMillisecond;
 377                                                         if (diff > Int32.MaxValue)
 378                                                                 ms_wait = Int32.MaxValue - 1;
 379                                                         else {
 380                                                                 ms_wait = (int)(diff);
 381                                                                 if (ms_wait < 0)
 382                                                                         ms_wait = 0;
 383                                                         }
 384                                                 }
 385                                         }
 386                                         // Wait until due time or a timer is changed and moves from/to the first place in the list.
 387                                         changed.WaitOne (ms_wait);
 388                                 }
 389                         }
 390
 391                         void ShrinkIfNeeded (ArrayList list, int initial)
 392                         {
 393                                 int capacity = list.Capacity;
 394                                 int count = list.Count;
 395                                 if (capacity > initial && count > 0 && (capacity / count) > 3)
 396                                         list.Capacity = count * 2;
 397                         }
 398
 399                         /*
 400                         void PrintList ()
 401                         {
 402                                 Console.WriteLine ("BEGIN--");
 403                                 for (int i = 0; i < list.Count; i++) {
 404                                         Timer timer = (Timer) list.GetByIndex (i);
 405                                         Console.WriteLine ("{0}: {1}", i, timer.next_run);
 406                                 }
 407                                 Console.WriteLine ("END----");
 408                         }
 409                         */
 410                 }
 411         }
 412 }
 413