xref: /recipes/reactor/s11-s10-TimerQueue.cc.diff

 // excerpts from http://code.google.com/p/muduo/
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the License file.
 //
 // Author: Shuo Chen (chenshuo at chenshuo dot com)
 
 #define __STDC_LIMIT_MACROS
 #include "TimerQueue.h"
 
 #include "logging/Logging.h"
 #include "EventLoop.h"
 #include "Timer.h"
 #include "TimerId.h"
 
 #include <boost/bind.hpp>
+#include <boost/foreach.hpp>
 
 #include <sys/timerfd.h>
 
 namespace muduo
 {
 namespace detail
 {
 
 int createTimerfd()
 {
   int timerfd = ::timerfd_create(CLOCK_MONOTONIC,
                                  TFD_NONBLOCK | TFD_CLOEXEC);
   if (timerfd < 0)
   {
     LOG_SYSFATAL << "Failed in timerfd_create";
   }
   return timerfd;
 }
 
 struct timespec howMuchTimeFromNow(Timestamp when)
 {
   int64_t microseconds = when.microSecondsSinceEpoch()
                          - Timestamp::now().microSecondsSinceEpoch();
   if (microseconds < 100)
   {
     microseconds = 100;
   }
   struct timespec ts;
   ts.tv_sec = static_cast<time_t>(
       microseconds / Timestamp::kMicroSecondsPerSecond);
   ts.tv_nsec = static_cast<long>(
       (microseconds % Timestamp::kMicroSecondsPerSecond) * 1000);
   return ts;
 }
 
 void readTimerfd(int timerfd, Timestamp now)
 {
   uint64_t howmany;
   ssize_t n = ::read(timerfd, &howmany, sizeof howmany);
   LOG_TRACE << "TimerQueue::handleRead() " << howmany << " at " << now.toString();
   if (n != sizeof howmany)
   {
     LOG_ERROR << "TimerQueue::handleRead() reads " << n << " bytes instead of 8";
   }
 }
 
 void resetTimerfd(int timerfd, Timestamp expiration)
 {
   // wake up loop by timerfd_settime()
   struct itimerspec newValue;
   struct itimerspec oldValue;
   bzero(&newValue, sizeof newValue);
   bzero(&oldValue, sizeof oldValue);
   newValue.it_value = howMuchTimeFromNow(expiration);
   int ret = ::timerfd_settime(timerfd, 0, &newValue, &oldValue);
   if (ret)
   {
     LOG_SYSERR << "timerfd_settime()";
   }
 }
 
 }
 }
 
 using namespace muduo;
 using namespace muduo::detail;
 
 TimerQueue::TimerQueue(EventLoop* loop)
   : loop_(loop),
     timerfd_(createTimerfd()),
     timerfdChannel_(loop, timerfd_),
-    timers_()
+    timers_(),
+    callingExpiredTimers_(false)
 {
   timerfdChannel_.setReadCallback(
       boost::bind(&TimerQueue::handleRead, this));
   // we are always reading the timerfd, we disarm it with timerfd_settime.
   timerfdChannel_.enableReading();
 }
 
 TimerQueue::~TimerQueue()
 {
   ::close(timerfd_);
   // do not remove channel, since we're in EventLoop::dtor();
   for (TimerList::iterator it = timers_.begin();
       it != timers_.end(); ++it)
   {
     delete it->second;
   }
 }
 
 TimerId TimerQueue::addTimer(const TimerCallback& cb,
                              Timestamp when,
                              double interval)
 {
   Timer* timer = new Timer(cb, when, interval);
   loop_->runInLoop(
       boost::bind(&TimerQueue::addTimerInLoop, this, timer));
!  return TimerId(timer, timer->sequence());
 }
 
+void TimerQueue::cancel(TimerId timerId)
+{
+  loop_->runInLoop(
+      boost::bind(&TimerQueue::cancelInLoop, this, timerId));
+}
+
 void TimerQueue::addTimerInLoop(Timer* timer)
 {
   loop_->assertInLoopThread();
   bool earliestChanged = insert(timer);
 
   if (earliestChanged)
   {
     resetTimerfd(timerfd_, timer->expiration());
   }
 }
 
+void TimerQueue::cancelInLoop(TimerId timerId)
+{
+  loop_->assertInLoopThread();
+  assert(timers_.size() == activeTimers_.size());
+  ActiveTimer timer(timerId.timer_, timerId.seq_);
+  ActiveTimerSet::iterator it = activeTimers_.find(timer);
+  if (it != activeTimers_.end())
+  {
+    size_t n = timers_.erase(Entry(it->first->expiration(), it->first));
+    assert(n == 1); (void)n;
+    delete it->first; // FIXME: no delete please
+    activeTimers_.erase(it);
+  }
+  else if (callingExpiredTimers_)
+  {
+    cancelingTimers_.insert(timer);
+  }
+  assert(timers_.size() == activeTimers_.size());
+}
+
 void TimerQueue::handleRead()
 {
   loop_->assertInLoopThread();
   Timestamp now(Timestamp::now());
   readTimerfd(timerfd_, now);
 
   std::vector<Entry> expired = getExpired(now);
 
+  callingExpiredTimers_ = true;
+  cancelingTimers_.clear();
   // safe to callback outside critical section
   for (std::vector<Entry>::iterator it = expired.begin();
       it != expired.end(); ++it)
   {
     it->second->run();
   }
+  callingExpiredTimers_ = false;
 
   reset(expired, now);
 }
 
 std::vector<TimerQueue::Entry> TimerQueue::getExpired(Timestamp now)
 {
+  assert(timers_.size() == activeTimers_.size());
   std::vector<Entry> expired;
   Entry sentry = std::make_pair(now, reinterpret_cast<Timer*>(UINTPTR_MAX));
   TimerList::iterator it = timers_.lower_bound(sentry);
   assert(it == timers_.end() || now < it->first);
   std::copy(timers_.begin(), it, back_inserter(expired));
   timers_.erase(timers_.begin(), it);
 
+  BOOST_FOREACH(Entry entry, expired)
+  {
+    ActiveTimer timer(entry.second, entry.second->sequence());
+    size_t n = activeTimers_.erase(timer);
+    assert(n == 1); (void)n;
+  }
+
+  assert(timers_.size() == activeTimers_.size());
   return expired;
 }
 
 void TimerQueue::reset(const std::vector<Entry>& expired, Timestamp now)
 {
   Timestamp nextExpire;
 
   for (std::vector<Entry>::const_iterator it = expired.begin();
       it != expired.end(); ++it)
   {
+    ActiveTimer timer(it->second, it->second->sequence());
!    if (it->second->repeat()
+        && cancelingTimers_.find(timer) == cancelingTimers_.end())
     {
       it->second->restart(now);
       insert(it->second);
     }
     else
     {
       // FIXME move to a free list
       delete it->second;
     }
   }
 
   if (!timers_.empty())
   {
     nextExpire = timers_.begin()->second->expiration();
   }
 
   if (nextExpire.valid())
   {
     resetTimerfd(timerfd_, nextExpire);
   }
 }
 
 bool TimerQueue::insert(Timer* timer)
 {
+  loop_->assertInLoopThread();
+  assert(timers_.size() == activeTimers_.size());
   bool earliestChanged = false;
   Timestamp when = timer->expiration();
   TimerList::iterator it = timers_.begin();
   if (it == timers_.end() || when < it->first)
   {
     earliestChanged = true;
   }
+
+  {
     std::pair<TimerList::iterator, bool> result
       = timers_.insert(Entry(when, timer));
     assert(result.second); (void)result;
+  }
+  {
+    std::pair<ActiveTimerSet::iterator, bool> result
+      = activeTimers_.insert(ActiveTimer(timer, timer->sequence()));
+    assert(result.second); (void)result;
+  }
+
+  assert(timers_.size() == activeTimers_.size());
   return earliestChanged;
 }