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.Generic;
  33 using System.Collections;
  34
  35 namespace System.Threading
  36 {
  37         [ComVisible (true)]
  38         public sealed class Timer
  39                 : MarshalByRefObject, IDisposable
  40         {
  41                 static readonly Scheduler scheduler = Scheduler.Instance;
  42 #region Timer instance fields
  43                 TimerCallback callback;
  44                 object state;
  45                 long due_time_ms;
  46                 long period_ms;
  47                 long next_run; // in ticks. Only 'Scheduler' can change it except for new timers without due time.
  48                 bool disposed;
  49 #endregion
  50                 public Timer (TimerCallback callback, object state, int dueTime, int period)
  51                 {
  52                         Init (callback, state, dueTime, period);
  53                 }
  54
  55                 public Timer (TimerCallback callback, object state, long dueTime, long period)
  56                 {
  57                         Init (callback, state, dueTime, period);
  58                 }
  59
  60                 public Timer (TimerCallback callback, object state, TimeSpan dueTime, TimeSpan period)
  61                 {
  62                         Init (callback, state, (long)dueTime.TotalMilliseconds, (long)period.TotalMilliseconds);
  63                 }
  64
  65                 [CLSCompliant(false)]
  66                 public Timer (TimerCallback callback, object state, uint dueTime, uint period)
  67                 {
  68                         // convert all values to long - with a special case for -1 / 0xffffffff
  69                         long d = (dueTime == UInt32.MaxValue) ? Timeout.Infinite : (long) dueTime;
  70                         long p = (period == UInt32.MaxValue) ? Timeout.Infinite : (long) period;
  71                         Init (callback, state, d, p);
  72                 }
  73
  74                 public Timer (TimerCallback callback)
  75                 {
  76                         Init (callback, this, Timeout.Infinite, Timeout.Infinite);
  77                 }
  78
  79                 void Init (TimerCallback callback, object state, long dueTime, long period)
  80                 {
  81                         if (callback == null)
  82                                 throw new ArgumentNullException ("callback");
  83
  84                         this.callback = callback;
  85                         this.state = state;
  86
  87                         Change (dueTime, period, true);
  88                 }
  89
  90                 public bool Change (int dueTime, int period)
  91                 {
  92                         return Change (dueTime, period, false);
  93                 }
  94
  95                 public bool Change (TimeSpan dueTime, TimeSpan period)
  96                 {
  97                         return Change ((long)dueTime.TotalMilliseconds, (long)period.TotalMilliseconds, false);
  98                 }
  99
 100                 [CLSCompliant(false)]
 101                 public bool Change (uint dueTime, uint period)
 102                 {
 103                         // convert all values to long - with a special case for -1 / 0xffffffff
 104                         long d = (dueTime == UInt32.MaxValue) ? Timeout.Infinite : (long) dueTime;
 105                         long p = (period == UInt32.MaxValue) ? Timeout.Infinite : (long) period;
 106                         return Change (d, p, false);
 107                 }
 108
 109                 public void Dispose ()
 110                 {
 111                         if (disposed)
 112                                 return;
 113
 114                         disposed = true;
 115                         scheduler.Remove (this);
 116                 }
 117
 118                 public bool Change (long dueTime, long period)
 119                 {
 120                         return Change (dueTime, period, false);
 121                 }
 122
 123                 const long MaxValue = UInt32.MaxValue - 1;
 124
 125                 bool Change (long dueTime, long period, bool first)
 126                 {
 127                         if (dueTime > MaxValue)
 128                                 throw new ArgumentOutOfRangeException ("dueTime", "Due time too large");
 129
 130                         if (period > MaxValue)
 131                                 throw new ArgumentOutOfRangeException ("period", "Period too large");
 132
 133                         // Timeout.Infinite == -1, so this accept everything greater than -1
 134                         if (dueTime < Timeout.Infinite)
 135                                 throw new ArgumentOutOfRangeException ("dueTime");
 136
 137                         if (period < Timeout.Infinite)
 138                                 throw new ArgumentOutOfRangeException ("period");
 139
 140                         if (disposed)
 141                                 return false;
 142
 143                         due_time_ms = dueTime;
 144                         period_ms = period;
 145                         long nr;
 146                         if (dueTime == 0) {
 147                                 nr = 0; // Due now
 148                         } else if (dueTime < 0) { // Infinite == -1
 149                                 nr = long.MaxValue;
 150                                 /* No need to call Change () */
 151                                 if (first) {
 152                                         next_run = nr;
 153                                         return true;
 154                                 }
 155                         } else {
 156                                 nr = dueTime * TimeSpan.TicksPerMillisecond + DateTime.GetTimeMonotonic ();
 157                         }
 158
 159                         scheduler.Change (this, nr);
 160                         return true;
 161                 }
 162
 163                 public bool Dispose (WaitHandle notifyObject)
 164                 {
 165                         if (notifyObject == null)
 166                                 throw new ArgumentNullException ("notifyObject");
 167                         Dispose ();
 168                         NativeEventCalls.SetEvent_internal (notifyObject.Handle);
 169                         return true;
 170                 }
 171
 172                 sealed class TimerComparer : IComparer {
 173                         public int Compare (object x, object y)
 174                         {
 175                                 Timer tx = (x as Timer);
 176                                 if (tx == null)
 177                                         return -1;
 178                                 Timer ty = (y as Timer);
 179                                 if (ty == null)
 180                                         return 1;
 181                                 long result = tx.next_run - ty.next_run;
 182                                 if (result == 0)
 183                                         return x == y ? 0 : -1;
 184                                 return result > 0 ? 1 : -1;
 185                         }
 186                 }
 187
 188                 sealed class Scheduler {
 189                         static Scheduler instance;
 190                         SortedList list;
 191                         ManualResetEvent changed;
 192
 193                         static Scheduler ()
 194                         {
 195                                 instance = new Scheduler ();
 196                         }
 197
 198                         public static Scheduler Instance {
 199                                 get { return instance; }
 200                         }
 201
 202                         private Scheduler ()
 203                         {
 204                                 changed = new ManualResetEvent (false);
 205                                 list = new SortedList (new TimerComparer (), 1024);
 206                                 Thread thread = new Thread (SchedulerThread);
 207                                 thread.IsBackground = true;
 208                                 thread.Start ();
 209                         }
 210
 211                         public void Remove (Timer timer)
 212                         {
 213                                 // We do not keep brand new items or those with no due time.
 214                                 if (timer.next_run == 0 || timer.next_run == Int64.MaxValue)
 215                                         return;
 216
 217                                 lock (this) {
 218                                         // If this is the next item due (index = 0), the scheduler will wake up and find nothing.
 219                                         // No need to Pulse ()
 220                                         InternalRemove (timer);
 221                                 }
 222                         }
 223
 224                         public void Change (Timer timer, long new_next_run)
 225                         {
 226                                 bool wake = false;
 227                                 lock (this) {
 228                                         InternalRemove (timer);
 229                                         if (new_next_run == Int64.MaxValue) {
 230                                                 timer.next_run = new_next_run;
 231                                                 return;
 232                                         }
 233
 234                                         if (!timer.disposed) {
 235                                                 // We should only change next_run after removing and before adding
 236                                                 timer.next_run = new_next_run;
 237                                                 Add (timer);
 238                                                 // If this timer is next in line, wake up the scheduler
 239                                                 wake = (list.GetByIndex (0) == timer);
 240                                         }
 241                                 }
 242                                 if (wake)
 243                                         changed.Set ();
 244                         }
 245
 246                         // lock held by caller
 247                         int FindByDueTime (long nr)
 248                         {
 249                                 int min = 0;
 250                                 int max = list.Count - 1;
 251                                 if (max < 0)
 252                                         return -1;
 253
 254                                 if (max < 20) {
 255                                         while (min <= max) {
 256                                                 Timer t = (Timer) list.GetByIndex (min);
 257                                                 if (t.next_run == nr)
 258                                                         return min;
 259                                                 if (t.next_run > nr)
 260                                                         return -1;
 261                                                 min++;
 262                                         }
 263                                         return -1;
 264                                 }
 265
 266                                 while (min <= max) {
 267                                         int half = min + ((max - min) >> 1);
 268                                         Timer t = (Timer) list.GetByIndex (half);
 269                                         if (nr == t.next_run)
 270                                                 return half;
 271                                         if (nr > t.next_run)
 272                                                 min = half + 1;
 273                                         else
 274                                                 max = half - 1;
 275                                 }
 276
 277                                 return -1;
 278                         }
 279
 280                         // This should be the only caller to list.Add!
 281                         void Add (Timer timer)
 282                         {
 283                                 // Make sure there are no collisions (10000 ticks == 1ms, so we should be safe here)
 284                                 // Do not use list.IndexOfKey here. See bug #648130
 285                                 int idx = FindByDueTime (timer.next_run);
 286                                 if (idx != -1) {
 287                                         bool up = (Int64.MaxValue - timer.next_run) > 20000 ? true : false;
 288                                         while (true) {
 289                                                 idx++;
 290                                                 if (up)
 291                                                         timer.next_run++;
 292                                                 else
 293                                                         timer.next_run--;
 294
 295                                                 if (idx >= list.Count)
 296                                                         break;
 297                                                 Timer t2 = (Timer) list.GetByIndex (idx);
 298                                                 if (t2.next_run != timer.next_run)
 299                                                         break;
 300                                         }
 301                                 }
 302                                 list.Add (timer, timer);
 303                                 //PrintList ();
 304                         }
 305
 306                         int InternalRemove (Timer timer)
 307                         {
 308                                 int idx = list.IndexOfKey (timer);
 309                                 if (idx >= 0)
 310                                         list.RemoveAt (idx);
 311                                 return idx;
 312                         }
 313
 314                         static WaitCallback TimerCaller = new WaitCallback (TimerCB);
 315                         static void TimerCB (object o)
 316                         {
 317                                 Timer timer = (Timer) o;
 318                                 try {
 319                                         timer.callback (timer.state);
 320                                 } catch {}
 321                         }
 322
 323                         void SchedulerThread ()
 324                         {
 325                                 Thread.CurrentThread.Name = "Timer-Scheduler";
 326                                 var new_time = new List<Timer> (512);
 327                                 while (true) {
 328                                         int ms_wait = -1;
 329                                         long ticks = DateTime.GetTimeMonotonic ();
 330                                         lock (this) {
 331                                                 changed.Reset ();
 332                                                 //PrintList ();
 333                                                 int i;
 334                                                 int count = list.Count;
 335                                                 for (i = 0; i < count; i++) {
 336                                                         Timer timer = (Timer) list.GetByIndex (i);
 337                                                         if (timer.next_run > ticks)
 338                                                                 break;
 339
 340                                                         list.RemoveAt (i);
 341                                                         count--;
 342                                                         i--;
 343                                                         ThreadPool.UnsafeQueueUserWorkItem (TimerCaller, timer);
 344                                                         long period = timer.period_ms;
 345                                                         long due_time = timer.due_time_ms;
 346                                                         bool no_more = (period == -1 || ((period == 0 || period == Timeout.Infinite) && due_time != Timeout.Infinite));
 347                                                         if (no_more) {
 348                                                                 timer.next_run = Int64.MaxValue;
 349                                                         } else {
 350                                                                 timer.next_run = DateTime.GetTimeMonotonic () + TimeSpan.TicksPerMillisecond * timer.period_ms;
 351                                                                 new_time.Add (timer);
 352                                                         }
 353                                                 }
 354
 355                                                 // Reschedule timers with a new due time
 356                                                 count = new_time.Count;
 357                                                 for (i = 0; i < count; i++) {
 358                                                         Timer timer = new_time [i];
 359                                                         Add (timer);
 360                                                 }
 361                                                 new_time.Clear ();
 362                                                 ShrinkIfNeeded (new_time, 512);
 363
 364                                                 // Shrink the list
 365                                                 int capacity = list.Capacity;
 366                                                 count = list.Count;
 367                                                 if (capacity > 1024 && count > 0 && (capacity / count) > 3)
 368                                                         list.Capacity = count * 2;
 369
 370                                                 long min_next_run = Int64.MaxValue;
 371                                                 if (list.Count > 0)
 372                                                         min_next_run = ((Timer) list.GetByIndex (0)).next_run;
 373
 374                                                 //PrintList ();
 375                                                 ms_wait = -1;
 376                                                 if (min_next_run != Int64.MaxValue) {
 377                                                         long diff = (min_next_run - DateTime.GetTimeMonotonic ())  / TimeSpan.TicksPerMillisecond;
 378                                                         if (diff > Int32.MaxValue)
 379                                                                 ms_wait = Int32.MaxValue - 1;
 380                                                         else {
 381                                                                 ms_wait = (int)(diff);
 382                                                                 if (ms_wait < 0)
 383                                                                         ms_wait = 0;
 384                                                         }
 385                                                 }
 386                                         }
 387                                         // Wait until due time or a timer is changed and moves from/to the first place in the list.
 388                                         changed.WaitOne (ms_wait);
 389                                 }
 390                         }
 391
 392                         void ShrinkIfNeeded (List<Timer> list, int initial)
 393                         {
 394                                 int capacity = list.Capacity;
 395                                 int count = list.Count;
 396                                 if (capacity > initial && count > 0 && (capacity / count) > 3)
 397                                         list.Capacity = count * 2;
 398                         }
 399
 400                         /*
 401                         void PrintList ()
 402                         {
 403                                 Console.WriteLine ("BEGIN--");
 404                                 for (int i = 0; i < list.Count; i++) {
 405                                         Timer timer = (Timer) list.GetByIndex (i);
 406                                         Console.WriteLine ("{0}: {1}", i, timer.next_run);
 407                                 }
 408                                 Console.WriteLine ("END----");
 409                         }
 410                         */
 411                 }
 412         }
 413 }
 414