/usr/include/boost/asio/detail
Edit: /usr/include/boost/asio/detail/timer_queue.hpp (9873B)
//
// detail/timer_queue.hpp
// ~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef BOOST_ASIO_DETAIL_TIMER_QUEUE_HPP
#define BOOST_ASIO_DETAIL_TIMER_QUEUE_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
namespace boost {
namespace asio {
namespace detail {
template
class timer_queue
: public timer_queue_base
{
public:
// The time type.
typedef typename Time_Traits::time_type time_type;
// The duration type.
typedef typename Time_Traits::duration_type duration_type;
// Per-timer data.
class per_timer_data
{
public:
per_timer_data() :
heap_index_((std::numeric_limits::max)()),
next_(0), prev_(0)
{
}
private:
friend class timer_queue;
// The operations waiting on the timer.
op_queue op_queue_;
// The index of the timer in the heap.
std::size_t heap_index_;
// Pointers to adjacent timers in a linked list.
per_timer_data* next_;
per_timer_data* prev_;
};
// Constructor.
timer_queue()
: timers_(),
heap_()
{
}
// Add a new timer to the queue. Returns true if this is the timer that is
// earliest in the queue, in which case the reactor's event demultiplexing
// function call may need to be interrupted and restarted.
bool enqueue_timer(const time_type& time, per_timer_data& timer, wait_op* op)
{
// Enqueue the timer object.
if (timer.prev_ == 0 && &timer != timers_)
{
if (this->is_positive_infinity(time))
{
// No heap entry is required for timers that never expire.
timer.heap_index_ = (std::numeric_limits::max)();
}
else
{
// Put the new timer at the correct position in the heap. This is done
// first since push_back() can throw due to allocation failure.
timer.heap_index_ = heap_.size();
heap_entry entry = { time, &timer };
heap_.push_back(entry);
up_heap(heap_.size() - 1);
}
// Insert the new timer into the linked list of active timers.
timer.next_ = timers_;
timer.prev_ = 0;
if (timers_)
timers_->prev_ = &timer;
timers_ = &timer;
}
// Enqueue the individual timer operation.
timer.op_queue_.push(op);
// Interrupt reactor only if newly added timer is first to expire.
return timer.heap_index_ == 0 && timer.op_queue_.front() == op;
}
// Whether there are no timers in the queue.
virtual bool empty() const
{
return timers_ == 0;
}
// Get the time for the timer that is earliest in the queue.
virtual long wait_duration_msec(long max_duration) const
{
if (heap_.empty())
return max_duration;
return this->to_msec(
Time_Traits::to_posix_duration(
Time_Traits::subtract(heap_[0].time_, Time_Traits::now())),
max_duration);
}
// Get the time for the timer that is earliest in the queue.
virtual long wait_duration_usec(long max_duration) const
{
if (heap_.empty())
return max_duration;
return this->to_usec(
Time_Traits::to_posix_duration(
Time_Traits::subtract(heap_[0].time_, Time_Traits::now())),
max_duration);
}
// Dequeue all timers not later than the current time.
virtual void get_ready_timers(op_queue& ops)
{
if (!heap_.empty())
{
const time_type now = Time_Traits::now();
while (!heap_.empty() && !Time_Traits::less_than(now, heap_[0].time_))
{
per_timer_data* timer = heap_[0].timer_;
ops.push(timer->op_queue_);
remove_timer(*timer);
}
}
}
// Dequeue all timers.
virtual void get_all_timers(op_queue& ops)
{
while (timers_)
{
per_timer_data* timer = timers_;
timers_ = timers_->next_;
ops.push(timer->op_queue_);
timer->next_ = 0;
timer->prev_ = 0;
}
heap_.clear();
}
// Cancel and dequeue operations for the given timer.
std::size_t cancel_timer(per_timer_data& timer, op_queue& ops,
std::size_t max_cancelled = (std::numeric_limits::max)())
{
std::size_t num_cancelled = 0;
if (timer.prev_ != 0 || &timer == timers_)
{
while (wait_op* op = (num_cancelled != max_cancelled)
? timer.op_queue_.front() : 0)
{
op->ec_ = boost::asio::error::operation_aborted;
timer.op_queue_.pop();
ops.push(op);
++num_cancelled;
}
if (timer.op_queue_.empty())
remove_timer(timer);
}
return num_cancelled;
}
// Move operations from one timer to another, empty timer.
void move_timer(per_timer_data& target, per_timer_data& source)
{
target.op_queue_.push(source.op_queue_);
target.heap_index_ = source.heap_index_;
source.heap_index_ = (std::numeric_limits::max)();
if (target.heap_index_ < heap_.size())
heap_[target.heap_index_].timer_ = ⌖
if (timers_ == &source)
timers_ = ⌖
if (source.prev_)
source.prev_->next_ = ⌖
if (source.next_)
source.next_->prev_= ⌖
target.next_ = source.next_;
target.prev_ = source.prev_;
source.next_ = 0;
source.prev_ = 0;
}
private:
// Move the item at the given index up the heap to its correct position.
void up_heap(std::size_t index)
{
while (index > 0)
{
std::size_t parent = (index - 1) / 2;
if (!Time_Traits::less_than(heap_[index].time_, heap_[parent].time_))
break;
swap_heap(index, parent);
index = parent;
}
}
// Move the item at the given index down the heap to its correct position.
void down_heap(std::size_t index)
{
std::size_t child = index * 2 + 1;
while (child < heap_.size())
{
std::size_t min_child = (child + 1 == heap_.size()
|| Time_Traits::less_than(
heap_[child].time_, heap_[child + 1].time_))
? child : child + 1;
if (Time_Traits::less_than(heap_[index].time_, heap_[min_child].time_))
break;
swap_heap(index, min_child);
index = min_child;
child = index * 2 + 1;
}
}
// Swap two entries in the heap.
void swap_heap(std::size_t index1, std::size_t index2)
{
heap_entry tmp = heap_[index1];
heap_[index1] = heap_[index2];
heap_[index2] = tmp;
heap_[index1].timer_->heap_index_ = index1;
heap_[index2].timer_->heap_index_ = index2;
}
// Remove a timer from the heap and list of timers.
void remove_timer(per_timer_data& timer)
{
// Remove the timer from the heap.
std::size_t index = timer.heap_index_;
if (!heap_.empty() && index < heap_.size())
{
if (index == heap_.size() - 1)
{
timer.heap_index_ = (std::numeric_limits::max)();
heap_.pop_back();
}
else
{
swap_heap(index, heap_.size() - 1);
timer.heap_index_ = (std::numeric_limits::max)();
heap_.pop_back();
if (index > 0 && Time_Traits::less_than(
heap_[index].time_, heap_[(index - 1) / 2].time_))
up_heap(index);
else
down_heap(index);
}
}
// Remove the timer from the linked list of active timers.
if (timers_ == &timer)
timers_ = timer.next_;
if (timer.prev_)
timer.prev_->next_ = timer.next_;
if (timer.next_)
timer.next_->prev_= timer.prev_;
timer.next_ = 0;
timer.prev_ = 0;
}
// Determine if the specified absolute time is positive infinity.
template
static bool is_positive_infinity(const Time_Type&)
{
return false;
}
// Determine if the specified absolute time is positive infinity.
template
static bool is_positive_infinity(
const boost::date_time::base_time& time)
{
return time.is_pos_infinity();
}
// Helper function to convert a duration into milliseconds.
template
long to_msec(const Duration& d, long max_duration) const
{
if (d.ticks() <= 0)
return 0;
int64_t msec = d.total_milliseconds();
if (msec == 0)
return 1;
if (msec > max_duration)
return max_duration;
return static_cast(msec);
}
// Helper function to convert a duration into microseconds.
template
long to_usec(const Duration& d, long max_duration) const
{
if (d.ticks() <= 0)
return 0;
int64_t usec = d.total_microseconds();
if (usec == 0)
return 1;
if (usec > max_duration)
return max_duration;
return static_cast(usec);
}
// The head of a linked list of all active timers.
per_timer_data* timers_;
struct heap_entry
{
// The time when the timer should fire.
time_type time_;
// The associated timer with enqueued operations.
per_timer_data* timer_;
};
// The heap of timers, with the earliest timer at the front.
std::vector heap_;
};
} // namespace detail
} // namespace asio
} // namespace boost
#include
#endif // BOOST_ASIO_DETAIL_TIMER_QUEUE_HPP