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Allow Timers to be cancelled during callback execution #94

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Allow Timers to be cancelled during callback execution #94

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2 changes: 2 additions & 0 deletions src/misc/pv/timer.h
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Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,8 @@ class epicsShareClass TimerCallback {
epicsTime timeToRun;
double period;
bool onList;
bool cancelled;
bool processing;
friend class Timer;
struct IncreasingTime;
};
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15 changes: 13 additions & 2 deletions src/misc/timer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,9 @@ namespace epics { namespace pvData {

TimerCallback::TimerCallback()
: period(0.0),
onList(false)
onList(false),
cancelled(false),
processing(false)
{
}

Expand All @@ -50,6 +52,7 @@ void Timer::addElement(TimerCallbackPtr const & timerCallback)
temp.push_back(timerCallback);

timerCallback->onList = true;
timerCallback->cancelled = false;

// merge sorted lists.
// for us effectively insertion sort.
Expand All @@ -60,6 +63,11 @@ void Timer::addElement(TimerCallbackPtr const & timerCallback)
bool Timer::cancel(TimerCallbackPtr const &timerCallback)
{
Lock xx(mutex);
/* If we're processing, just set the cancel flag */
if (timerCallback->processing) {
timerCallback->cancelled = true;
return true;
}
if(!timerCallback->onList) return false;
if(!alive) {
timerCallback->onList = false;
Expand Down Expand Up @@ -107,6 +115,7 @@ void Timer::run()
TimerCallbackPtr work;
work.swap(queue.front());
work->onList = false;
work->processing = true;
queue.pop_front();

{
Expand All @@ -115,7 +124,9 @@ void Timer::run()
work->callback();
}

if(work->period > 0.0 && alive) {
work->processing = false;

if(work->period > 0.0 && alive && !work->cancelled) {
work->timeToRun += work->period;
addElement(work);
}
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