RTScheduler.cc

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#include "RTScheduler.hh"
#include "RTSchedulable.hh"
#include "ranges.hh"
#include <limits>
 
namespace openmsx {
 
struct EqualRTSchedulable {
        explicit EqualRTSchedulable(const RTSchedulable& schedulable_)
                : schedulable(schedulable_) {}
        bool operator()(const RTSyncPoint& sp) const {
                return sp.schedulable == &schedulable;
        }
        const RTSchedulable& schedulable;
};
 
void RTScheduler::add(uint64_t delta, RTSchedulable& schedulable)
{
        queue.insert(RTSyncPoint{Timer::getTime() + delta, &schedulable},
                     [](RTSyncPoint& sp) {
                             sp.time = std::numeric_limits<uint64_t>::max(); },
                     [](const RTSyncPoint& x, const RTSyncPoint& y) {
                             return x.time < y.time; });
}
 
bool RTScheduler::remove(RTSchedulable& schedulable)
{
        return queue.remove(EqualRTSchedulable(schedulable));
}
 
bool RTScheduler::isPending(const RTSchedulable& schedulable) const
{
        return ranges::any_of(queue, EqualRTSchedulable(schedulable));
}
 
void RTScheduler::scheduleHelper(uint64_t limit)
{
        // Process at most this many events to prevent getting stuck in an
        // infinite loop when a RTSchedulable keeps on rescheduling itself in
        // the (too) near future.
        auto count = queue.size();
        while (true) {
                auto* schedulable = queue.front().schedulable;
                queue.remove_front();
 
                schedulable->executeRT();
 
                // It's possible RTSchedulables are canceled in the mean time,
                // so we can't rely on 'count' to replace this empty check.
                if (queue.empty()) break;
                if (queue.front().time > limit) [[likely]] break;
                if (--count == 0) break;
        }
}
 
} // namespace openmsx