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#include "cru/base/platform/unix/EventLoop.h"
#include "cru/base/Exception.h"
#include "cru/base/log/Logger.h"
#include <poll.h>
#include <algorithm>
#include <chrono>
#include <thread>
namespace cru::platform::unix {
int UnixTimerFile::GetReadFd() const { return this->read_fd_; }
UnixEventLoop::UnixEventLoop() : timer_tag_(1), polls_(1), poll_actions_(1) {
auto timer_pipe = OpenUniDirectionalPipe(UnixPipeFlags::NonBlock);
timer_pipe_read_end_ = std::move(timer_pipe.read);
timer_pipe_write_end_ = std::move(timer_pipe.write);
polls_[0].fd = timer_pipe_read_end_;
polls_[0].events = POLLIN;
poll_actions_[0] = [](auto _) {};
}
UnixEventLoop::~UnixEventLoop() { CRU_LOG_TAG_DEBUG("Event loop destroyed."); }
int UnixEventLoop::Run() {
CRU_LOG_TAG_DEBUG("Event loop started.");
running_thread_ = std::this_thread::get_id();
while (!exit_code_) {
int poll_timeout = -1;
while (CheckPoll()) {
continue;
}
while (CheckTimer()) {
continue;
}
while (ReadTimerPipe()) {
continue;
}
if (!timers_.empty()) {
poll_timeout =
std::ranges::min_element(timers_, [](const TimerData &left,
const TimerData &right) {
return left.timeout < right.timeout;
})->timeout.count();
}
auto start = std::chrono::steady_clock::now();
auto result = ::poll(polls_.data(), polls_.size(), poll_timeout);
if (result < 0) {
throw Exception("Failed to poll in event loop.");
}
auto end = std::chrono::steady_clock::now();
auto time =
std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
for (auto &timer : timers_) {
timer.timeout -= time;
}
}
return exit_code_.value();
}
void UnixEventLoop::RequestQuit(int exit_code) {
exit_code_ = exit_code;
if (std::this_thread::get_id() != running_thread_) {
SetImmediate([] {});
}
}
int UnixEventLoop::SetTimer(std::function<void()> action,
std::chrono::milliseconds timeout, bool repeat) {
if (repeat) {
if (timeout <= std::chrono::milliseconds::zero()) {
throw Exception("Interval must be bigger than 0.");
}
} else {
if (timeout < std::chrono::milliseconds::zero()) {
throw Exception("Timeout must be at least 0.");
}
}
auto tag = timer_tag_++;
if (std::this_thread::get_id() == running_thread_) {
timers_.push_back(
TimerData(tag, std::move(timeout), repeat, std::move(action)));
} else {
auto timer =
new TimerData(tag, std::move(timeout), repeat, std::move(action));
timer_pipe_write_end_.Write(&timer, sizeof(decltype(timer)));
}
return tag;
}
void UnixEventLoop::CancelTimer(int id) {
if (std::this_thread::get_id() == running_thread_) {
RemoveTimer(id);
} else {
SetImmediate([this, id] { RemoveTimer(id); });
}
}
bool UnixEventLoop::CheckPoll() {
auto iter = std::ranges::find_if(
polls_, [](const pollfd &poll_fd) { return poll_fd.revents != 0; });
if (iter == polls_.cend()) {
return false;
}
auto &revents = iter->revents;
if (revents != 0) {
poll_actions_[iter - polls_.cbegin()](revents);
}
revents = 0;
return true;
}
bool UnixEventLoop::CheckTimer() {
auto iter = std::ranges::find_if(timers_, [](const TimerData &timer) {
return timer.timeout <= std::chrono::milliseconds::zero();
});
if (iter == timers_.end()) {
return false;
}
CRU_LOG_TAG_INFO("A timer is to be executed.");
auto &timer = *iter;
if (timer.repeat) {
while (timer.timeout <= std::chrono::milliseconds::zero()) {
timer.timeout += timer.original_timeout;
timer.action();
}
} else {
auto action = timer.action;
timers_.erase(iter);
action();
}
return true;
}
bool UnixEventLoop::ReadTimerPipe() {
TimerData *pointer;
constexpr size_t pointer_size = sizeof(decltype(pointer));
auto rest = pointer_size;
while (true) {
auto result = timer_pipe_read_end_.Read(&pointer, rest);
if (result == -1) { // If no data.
if (rest == pointer_size) {
return false;
} else {
continue; // Try read again (might spin), as we are in the middle of
// reading a pointer.
}
}
if (result == 0) {
throw Exception("Unexpected EOF of the timer pipe.");
}
rest -= result;
}
timers_.push_back(std::move(*pointer));
delete pointer;
CRU_LOG_TAG_INFO("A timer from pipe is received.");
return true;
}
void UnixEventLoop::RemoveTimer(int id) {
auto iter = std::ranges::find_if(
timers_, [id](const TimerData &timer) { return timer.id == id; });
if (iter != timers_.cend()) {
timers_.erase(iter);
}
}
} // namespace cru::platform::unix
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