transmission/libtransmission/timer-ev.cc

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// This file Copyright 2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <chrono>
#include <memory>
2022-08-17 16:08:36 +00:00
#include <utility>
#include <event2/event.h>
#include "timer-ev.h"
#include "tr-assert.h"
#include "utils-ev.h"
using namespace std::literals;
namespace libtransmission
{
class EvTimer final : public Timer
{
public:
explicit EvTimer(struct event_base* base)
: base_{ base }
{
}
EvTimer(EvTimer&&) = delete;
EvTimer(EvTimer const&) = delete;
EvTimer& operator=(EvTimer&&) = delete;
EvTimer& operator=(EvTimer const&) = delete;
~EvTimer() override = default;
void stop() override
{
if (!is_running_)
{
return;
}
event_del(evtimer_.get());
is_running_ = false;
}
void start() override
{
if (is_running_)
{
return;
}
using namespace std::chrono;
auto const secs = duration_cast<seconds>(interval_);
auto tv = timeval{};
tv.tv_sec = secs.count();
tv.tv_usec = static_cast<decltype(tv.tv_usec)>(duration_cast<microseconds>(interval_ - secs).count());
evtimer_add(evtimer_.get(), &tv);
is_running_ = true;
}
void setCallback(std::function<void()> callback) override
{
callback_ = std::move(callback);
}
[[nodiscard]] std::chrono::milliseconds interval() const noexcept override
{
return interval_;
}
void setInterval(std::chrono::milliseconds interval) override
{
TR_ASSERT_MSG(interval.count() > 0 || !isRepeating(), "repeating timers must have a positive interval");
if (interval_ == interval)
{
return;
}
interval_ = interval;
applyChanges();
}
[[nodiscard]] bool isRepeating() const noexcept override
{
return is_repeating_;
}
void setRepeating(bool repeating) override
{
if (is_repeating_ == repeating)
{
return;
}
is_repeating_ = repeating;
applyChanges();
}
private:
[[nodiscard]] static constexpr short events(bool is_repeating) noexcept
{
return static_cast<short>(EV_TIMEOUT | (is_repeating ? EV_PERSIST : 0));
}
void applyChanges()
{
auto const old_events = event_get_events(evtimer_.get());
auto const new_events = events(isRepeating());
auto const was_running = isRunning();
if (was_running)
{
stop();
}
if (new_events != old_events)
{
[[maybe_unused]] auto const val = event_assign(evtimer_.get(), base_, -1, new_events, &EvTimer::onTimer, this);
TR_ASSERT(val == 0);
}
if (was_running)
{
start();
}
}
static void onTimer(evutil_socket_t /*unused*/, short /*unused*/, void* vself)
{
static_cast<EvTimer*>(vself)->handleTimer();
}
void handleTimer()
{
is_running_ = is_repeating_;
TR_ASSERT(callback_);
callback_();
}
[[nodiscard]] constexpr bool isRunning() const noexcept
{
return is_running_;
}
std::chrono::milliseconds interval_ = 100ms;
bool is_repeating_ = false;
bool is_running_ = false;
std::function<void()> callback_;
struct event_base* const base_;
evhelpers::event_unique_ptr const evtimer_{ event_new(base_, -1, events(is_repeating_), &EvTimer::onTimer, this) };
};
std::unique_ptr<Timer> EvTimerMaker::create()
{
return std::make_unique<EvTimer>(event_base_);
}
} // namespace libtransmission