# Crow: include/crow/task_timer.h Source File

task_timer.h
#pragma once
#ifdef CROW_USE_BOOST
#include <boost/asio.hpp>
#include <boost/asio/basic_waitable_timer.hpp>
#else
#ifndef ASIO_STANDALONE
#define ASIO_STANDALONE
#endif
#include <asio.hpp>
#include <asio/basic_waitable_timer.hpp>
#endif
#include <chrono>
#include <functional>
#include <map>
#include <vector>
#include "crow/logging.h"
namespace crow
{
#ifdef CROW_USE_BOOST
namespace asio = boost::asio;
using error_code = boost::system::error_code;
#else
using error_code = asio::error_code;
#endif
namespace detail
{
/// A class for scheduling functions to be called after a specific amount of ticks. A tick is equal to 1 second.
class task_timer
{
public:
using task_type = std::function<void()>;
using identifier_type = size_t;
private:
using clock_type = std::chrono::steady_clock;
using time_type = clock_type::time_point;
public:
task_timer(asio::io_service& io_service):
io_service_(io_service), timer_(io_service_)
{
timer_.expires_after(std::chrono::seconds(1));
timer_.async_wait(
std::bind(&task_timer::tick_handler, this, std::placeholders::_1));
}
~task_timer() { timer_.cancel(); }
void cancel(identifier_type id)
{
tasks_.erase(id);
CROW_LOG_DEBUG << "task_timer cancelled: " << this << ' ' << id;
}
/// Schedule the given task to be executed after the default amount of ticks.
///
/// \return identifier_type Used to cancel the thread.
/// It is not bound to this task_timer instance and in some cases could lead to
/// undefined behavior if used with other task_timer objects or after the task
/// has been successfully executed.
identifier_type schedule(const task_type& task)
{
tasks_.insert(
{++highest_id_,
{clock_type::now() + std::chrono::seconds(get_default_timeout()),
task}});
CROW_LOG_DEBUG << "task_timer scheduled: " << this << ' ' << highest_id_;
return highest_id_;
}
/// Schedule the given task to be executed after the given time.
///
/// \param timeout The amount of ticks (seconds) to wait before execution.
///
/// \return identifier_type Used to cancel the thread.
/// It is not bound to this task_timer instance and in some cases could lead to
/// undefined behavior if used with other task_timer objects or after the task
/// has been successfully executed.
identifier_type schedule(const task_type& task, std::uint8_t timeout)
{
tasks_.insert({++highest_id_,
{clock_type::now() + std::chrono::seconds(timeout), task}});
CROW_LOG_DEBUG << "task_timer scheduled: " << this << ' ' << highest_id_;
return highest_id_;
}
/// Set the default timeout for this task_timer instance. (Default: 5)
///
/// \param timeout The amount of ticks (seconds) to wait before execution.
void set_default_timeout(std::uint8_t timeout) { default_timeout_ = timeout; }
/// Get the default timeout. (Default: 5)
std::uint8_t get_default_timeout() const { return default_timeout_; }
private:
void process_tasks()
{
time_type current_time = clock_type::now();
std::vector<identifier_type> finished_tasks;
for (const auto& task : tasks_)
{
if (task.second.first < current_time)
{
(task.second.second)();
finished_tasks.push_back(task.first);
CROW_LOG_DEBUG << "task_timer called: " << this << ' ' << task.first;
}
}
for (const auto& task : finished_tasks)
tasks_.erase(task);
// If no task is currently scheduled, reset the issued ids back to 0.
if (tasks_.empty()) highest_id_ = 0;
}
void tick_handler(const error_code& ec)
{
if (ec) return;
process_tasks();
timer_.expires_after(std::chrono::seconds(1));
timer_.async_wait(
std::bind(&task_timer::tick_handler, this, std::placeholders::_1));
}
private:
std::uint8_t default_timeout_{5};
asio::io_service& io_service_;
asio::basic_waitable_timer<clock_type> timer_;
std::map<identifier_type, std::pair<time_type, task_type>> tasks_;
// A continuosly increasing number to be issued to threads to identify them.
// If no tasks are scheduled, it will be reset to 0.
identifier_type highest_id_{0};
};
} // namespace detail
} // namespace crow
crow::detail::task_timer
A class for scheduling functions to be called after a specific amount of ticks. A tick is equal to 1 ...
Definition: task_timer.h:34
crow::detail::task_timer::schedule
identifier_type schedule(const task_type &task, std::uint8_t timeout)
Schedule the given task to be executed after the given time.
Definition: task_timer.h:86
crow::detail::task_timer::set_default_timeout
void set_default_timeout(std::uint8_t timeout)
Set the default timeout for this task_timer instance. (Default: 5)
Definition: task_timer.h:98
crow::detail::task_timer::schedule
identifier_type schedule(const task_type &task)
Schedule the given task to be executed after the default amount of ticks.
Definition: task_timer.h:67
crow::detail::task_timer::get_default_timeout
std::uint8_t get_default_timeout() const
Get the default timeout. (Default: 5)
Definition: task_timer.h:101
crow
The main namespace of the library. In this namespace is defined the most important classes and functi...