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/*
* Copyright © 2015 Canonical Ltd.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Authored by: Andreas Pokorny <andreas.pokorny@canonical.com>
*/
#include "mir/dispatch/action_queue.h"
#include <boost/throw_exception.hpp>
#include <sys/eventfd.h>
mir::dispatch::ActionQueue::ActionQueue()
: event_fd{eventfd(0, EFD_CLOEXEC|EFD_NONBLOCK)}
{
if (event_fd < 0)
BOOST_THROW_EXCEPTION((std::system_error{errno,
std::system_category(),
"Failed to create event fd for action queue"}));
}
mir::Fd mir::dispatch::ActionQueue::watch_fd() const
{
return event_fd;
}
void mir::dispatch::ActionQueue::enqueue(std::function<void()> const& action)
{
std::unique_lock<std::mutex> lock(list_lock);
actions.push_back(action);
wake();
}
bool mir::dispatch::ActionQueue::dispatch(FdEvents events)
{
if (events&FdEvent::error)
return false;
std::list<std::function<void()>> actions_to_process;
{
std::unique_lock<std::mutex> lock(list_lock);
consume();
std::swap(actions_to_process, actions);
}
while(!actions_to_process.empty())
{
actions_to_process.front()();
actions_to_process.pop_front();
}
return true;
}
mir::dispatch::FdEvents mir::dispatch::ActionQueue::relevant_events() const
{
return FdEvent::readable;
}
void mir::dispatch::ActionQueue::consume()
{
uint64_t num_actions;
if (read(event_fd, &num_actions, sizeof num_actions) != sizeof num_actions)
BOOST_THROW_EXCEPTION((std::system_error{errno,
std::system_category(),
"Failed to consume action queue notification"}));
}
void mir::dispatch::ActionQueue::wake()
{
uint64_t one_more{1};
if (write(event_fd, &one_more, sizeof one_more) != sizeof one_more)
BOOST_THROW_EXCEPTION((std::system_error{errno,
std::system_category(),
"Failed to wake action queue"}));
}
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