mpd/src/event/MultiSocketMonitor.cxx
Rosen Penev edc4989d9c
change errno.h to cerrno
The former is deprecated by C++14. It's also functionally the same.

From the standard:

19.4
The header<cerrno>is described in Table 43. Its contents are the same as
the POSIX header<errno.h>,except that errno shall be defined as a macro.
[Note: The intent is to remain in close alignment with the POSIX
standard.] A separate errno value shall be provided for each thread.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
2020-03-12 15:51:16 -07:00

151 lines
3.2 KiB
C++

/*
* Copyright 2003-2020 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "MultiSocketMonitor.hxx"
#include "Loop.hxx"
#include <algorithm>
#ifdef USE_EPOLL
#include <cerrno>
#endif
#ifndef _WIN32
#include <poll.h>
#endif
MultiSocketMonitor::MultiSocketMonitor(EventLoop &_loop) noexcept
:IdleMonitor(_loop),
timeout_event(_loop, BIND_THIS_METHOD(OnTimeout)) {
}
void
MultiSocketMonitor::Reset() noexcept
{
assert(GetEventLoop().IsInside());
fds.clear();
#ifdef USE_EPOLL
always_ready_fds.clear();
#endif
IdleMonitor::Cancel();
timeout_event.Cancel();
ready = refresh = false;
}
bool
MultiSocketMonitor::AddSocket(SocketDescriptor fd, unsigned events) noexcept
{
fds.emplace_front(*this, fd);
bool success = fds.front().Schedule(events);
if (!success) {
fds.pop_front();
#ifdef USE_EPOLL
if (errno == EPERM)
/* not supported by epoll (e.g. "/dev/null"):
add it to the "always ready" list */
always_ready_fds.push_front({fd, events});
#endif
}
return success;
}
void
MultiSocketMonitor::ClearSocketList() noexcept
{
assert(GetEventLoop().IsInside());
fds.clear();
#ifdef USE_EPOLL
always_ready_fds.clear();
#endif
}
#ifndef _WIN32
void
MultiSocketMonitor::ReplaceSocketList(pollfd *pfds, unsigned n) noexcept
{
#ifdef USE_EPOLL
always_ready_fds.clear();
#endif
pollfd *const end = pfds + n;
UpdateSocketList([pfds, end](SocketDescriptor fd) -> unsigned {
auto i = std::find_if(pfds, end, [fd](const struct pollfd &pfd){
return pfd.fd == fd.Get();
});
if (i == end)
return 0;
return std::exchange(i->events, 0);
});
for (auto i = pfds; i != end; ++i)
if (i->events != 0)
AddSocket(SocketDescriptor(i->fd), i->events);
}
#endif
void
MultiSocketMonitor::Prepare() noexcept
{
auto timeout = PrepareSockets();
#ifdef USE_EPOLL
if (!always_ready_fds.empty()) {
/* if there was at least one file descriptor not
supported by epoll, install a very short timeout
because we assume it's always ready */
constexpr std::chrono::steady_clock::duration ready_timeout =
std::chrono::milliseconds(1);
if (timeout < timeout.zero() || timeout > ready_timeout)
timeout = ready_timeout;
}
#endif
if (timeout >= timeout.zero())
timeout_event.Schedule(timeout);
else
timeout_event.Cancel();
}
void
MultiSocketMonitor::OnIdle() noexcept
{
if (ready) {
ready = false;
DispatchSockets();
/* TODO: don't refresh always; require users to call
InvalidateSockets() */
refresh = true;
}
if (refresh) {
refresh = false;
Prepare();
}
}