granicus.if.org Git - icinga2/blob - lib/base/timer.cpp

   1 /******************************************************************************
   2  * Icinga 2                                                                   *
   3  * Copyright (C) 2012-2014 Icinga Development Team (http://www.icinga.org)    *
   4  *                                                                            *
   5  * This program is free software; you can redistribute it and/or              *
   6  * modify it under the terms of the GNU General Public License                *
   7  * as published by the Free Software Foundation; either version 2             *
   8  * of the License, or (at your option) any later version.                     *
   9  *                                                                            *
  10  * This program is distributed in the hope that it will be useful,            *
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of             *
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
  13  * GNU General Public License for more details.                               *
  14  *                                                                            *
  15  * You should have received a copy of the GNU General Public License          *
  16  * along with this program; if not, write to the Free Software Foundation     *
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
  18  ******************************************************************************/
  19
  20 #include "base/timer.h"
  21 #include "base/application.h"
  22 #include "base/debug.h"
  23 #include "base/utility.h"
  24 #include <boost/bind.hpp>
  25 #include <boost/foreach.hpp>
  26 #include <boost/thread/thread.hpp>
  27 #include <boost/thread/mutex.hpp>
  28 #include <boost/thread/condition_variable.hpp>
  29 #include <boost/multi_index_container.hpp>
  30 #include <boost/multi_index/ordered_index.hpp>
  31 #include <boost/multi_index/key_extractors.hpp>
  32
  33 using namespace icinga;
  34
  35 struct TimerHolder
  36 {
  37         Timer::WeakPtr Object;
  38         double Next;
  39 };
  40
  41 typedef boost::multi_index_container<
  42         TimerHolder,
  43         boost::multi_index::indexed_by<
  44                 boost::multi_index::ordered_unique<boost::multi_index::member<TimerHolder, Timer::WeakPtr, &TimerHolder::Object> >,
  45                 boost::multi_index::ordered_non_unique<boost::multi_index::member<TimerHolder, double, &TimerHolder::Next> >
  46         >
  47 > TimerSet;
  48
  49 static boost::mutex l_Mutex;
  50 static boost::condition_variable l_CV;
  51 static boost::thread l_Thread;
  52 static bool l_StopThread;
  53 static TimerSet l_Timers;
  54
  55 /**
  56  * Constructor for the Timer class.
  57  */
  58 Timer::Timer(void)
  59         : m_Interval(0), m_Next(0)
  60 { }
  61
  62 /**
  63  * Initializes the timer sub-system.
  64  */
  65 void Timer::Initialize(void)
  66 {
  67         boost::mutex::scoped_lock lock(l_Mutex);
  68         l_StopThread = false;
  69         l_Thread = boost::thread(&Timer::TimerThreadProc);
  70 }
  71
  72 /**
  73  * Disables the timer sub-system.
  74  */
  75 void Timer::Uninitialize(void)
  76 {
  77         {
  78                 boost::mutex::scoped_lock lock(l_Mutex);
  79                 l_StopThread = true;
  80                 l_CV.notify_all();
  81         }
  82
  83         l_Thread.join();
  84 }
  85
  86 /**
  87  * Calls this timer.
  88  */
  89 void Timer::Call(void)
  90 {
  91         ASSERT(!OwnsLock());
  92
  93         Timer::Ptr self = GetSelf();
  94
  95         try {
  96                 OnTimerExpired(self);
  97         } catch (...) {
  98                 Reschedule();
  99
 100                 throw;
 101         }
 102
 103         Reschedule();
 104 }
 105
 106 /**
 107  * Sets the interval for this timer.
 108  *
 109  * @param interval The new interval.
 110  */
 111 void Timer::SetInterval(double interval)
 112 {
 113         ASSERT(!OwnsLock());
 114
 115         boost::mutex::scoped_lock lock(l_Mutex);
 116         m_Interval = interval;
 117 }
 118
 119 /**
 120  * Retrieves the interval for this timer.
 121  *
 122  * @returns The interval.
 123  */
 124 double Timer::GetInterval(void) const
 125 {
 126         ASSERT(!OwnsLock());
 127
 128         boost::mutex::scoped_lock lock(l_Mutex);
 129         return m_Interval;
 130 }
 131
 132 /**
 133  * Registers the timer and starts processing events for it.
 134  */
 135 void Timer::Start(void)
 136 {
 137         ASSERT(!OwnsLock());
 138
 139         {
 140                 boost::mutex::scoped_lock lock(l_Mutex);
 141                 m_Started = true;
 142         }
 143
 144         Reschedule();
 145 }
 146
 147 /**
 148  * Unregisters the timer and stops processing events for it.
 149  */
 150 void Timer::Stop(void)
 151 {
 152         ASSERT(!OwnsLock());
 153
 154         boost::mutex::scoped_lock lock(l_Mutex);
 155
 156         m_Started = false;
 157         l_Timers.erase(GetSelf());
 158
 159         /* Notify the worker thread that we've disabled a timer. */
 160         l_CV.notify_all();
 161 }
 162
 163 /**
 164  * Reschedules this timer.
 165  *
 166  * @param next The time when this timer should be called again. Use -1 to let
 167  *             the timer figure out a suitable time based on the interval.
 168  */
 169 void Timer::Reschedule(double next)
 170 {
 171         ASSERT(!OwnsLock());
 172
 173         boost::mutex::scoped_lock lock(l_Mutex);
 174
 175         if (next < 0) {
 176                 /* Don't schedule the next call if this is not a periodic timer. */
 177                 if (m_Interval <= 0)
 178                         return;
 179
 180                 next = Utility::GetTime() + m_Interval;
 181         }
 182
 183         m_Next = next;
 184
 185         if (m_Started) {
 186                 /* Remove and re-add the timer to update the index. */
 187                 l_Timers.erase(GetSelf());
 188
 189                 TimerHolder th;
 190                 th.Object = GetSelf();
 191                 th.Next = m_Next;
 192                 l_Timers.insert(th);
 193
 194                 /* Notify the worker that we've rescheduled a timer. */
 195                 l_CV.notify_all();
 196         }
 197 }
 198
 199 /**
 200  * Retrieves when the timer is next due.
 201  *
 202  * @returns The timestamp.
 203  */
 204 double Timer::GetNext(void) const
 205 {
 206         ASSERT(!OwnsLock());
 207
 208         boost::mutex::scoped_lock lock(l_Mutex);
 209         return m_Next;
 210 }
 211
 212 /**
 213  * Adjusts all timers by adding the specified amount of time to their
 214  * next scheduled timestamp.
 215  *
 216  * @param adjustment The adjustment.
 217  */
 218 void Timer::AdjustTimers(double adjustment)
 219 {
 220         boost::mutex::scoped_lock lock(l_Mutex);
 221
 222         double now = Utility::GetTime();
 223
 224         typedef boost::multi_index::nth_index<TimerSet, 1>::type TimerView;
 225         TimerView& idx = boost::get<1>(l_Timers);
 226
 227         std::vector<Timer::Ptr> timers;
 228
 229         BOOST_FOREACH(const TimerHolder& th, idx) {
 230                 Timer::Ptr timer = th.Object.lock();
 231
 232                 if (!timer)
 233                         continue;
 234
 235                 if (abs(now - (timer->m_Next + adjustment)) <
 236                     abs(now - timer->m_Next)) {
 237                         timer->m_Next += adjustment;
 238                         timers.push_back(timer);
 239                 }
 240         }
 241
 242         BOOST_FOREACH(const Timer::Ptr& timer, timers) {
 243                 l_Timers.erase(timer);
 244
 245                 TimerHolder th;
 246                 th.Object = timer;
 247                 th.Next = timer->m_Next;
 248                 l_Timers.insert(th);
 249         }
 250
 251         /* Notify the worker that we've rescheduled some timers. */
 252         l_CV.notify_all();
 253 }
 254
 255 /**
 256  * Worker thread proc for Timer objects.
 257  */
 258 void Timer::TimerThreadProc(void)
 259 {
 260         Utility::SetThreadName("Timer Thread");
 261
 262         for (;;) {
 263                 boost::mutex::scoped_lock lock(l_Mutex);
 264
 265                 typedef boost::multi_index::nth_index<TimerSet, 1>::type NextTimerView;
 266                 NextTimerView& idx = boost::get<1>(l_Timers);
 267
 268                 /* Wait until there is at least one timer. */
 269                 while (idx.empty() && !l_StopThread)
 270                         l_CV.wait(lock);
 271
 272                 if (l_StopThread)
 273                         break;
 274
 275                 NextTimerView::iterator it = idx.begin();
 276                 Timer::Ptr timer = it->Object.lock();
 277
 278                 if (!timer) {
 279                         /* Remove the timer from the list if it's not alive anymore. */
 280                         idx.erase(it);
 281                         continue;
 282                 }
 283
 284                 double wait = timer->m_Next - Utility::GetTime();
 285
 286                 if (wait > 0.01) {
 287                         /* Make sure the timer we just examined can be destroyed while we're waiting. */
 288                         timer.reset();
 289
 290                         /* Wait for the next timer. */
 291                         l_CV.timed_wait(lock, boost::posix_time::milliseconds(wait * 1000));
 292
 293                         continue;
 294                 }
 295
 296                 /* Remove the timer from the list so it doesn't get called again
 297                  * until the current call is completed. */
 298                 l_Timers.erase(timer);
 299
 300                 lock.unlock();
 301
 302                 /* Asynchronously call the timer. */
 303                 Utility::QueueAsyncCallback(boost::bind(&Timer::Call, timer));
 304         }
 305 }