/* * Copyright 2003-2016 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. */ #ifndef MPD_MULTI_SOCKET_MONITOR_HXX #define MPD_MULTI_SOCKET_MONITOR_HXX #include "check.h" #include "IdleMonitor.hxx" #include "TimeoutMonitor.hxx" #include "SocketMonitor.hxx" #include "Compiler.h" #include #include #include #ifdef WIN32 /* ERROR is a WIN32 macro that poisons our namespace; this is a kludge to allow us to use it anyway */ #ifdef ERROR #undef ERROR #endif #endif #ifndef WIN32 struct pollfd; #endif class EventLoop; /** * Similar to #SocketMonitor, but monitors multiple sockets. To use * it, implement the methods PrepareSockets() and DispatchSockets(). * In PrepareSockets(), use UpdateSocketList() and AddSocket(). * DispatchSockets() will be called if at least one socket is ready. */ class MultiSocketMonitor : IdleMonitor, TimeoutMonitor { class SingleFD final : public SocketMonitor { MultiSocketMonitor &multi; unsigned revents; public: SingleFD(MultiSocketMonitor &_multi, int _fd, unsigned events) :SocketMonitor(_fd, _multi.GetEventLoop()), multi(_multi), revents(0) { Schedule(events); } int GetFD() const { return SocketMonitor::Get(); } unsigned GetEvents() const { return SocketMonitor::GetScheduledFlags(); } void SetEvents(unsigned _events) { revents &= _events; SocketMonitor::Schedule(_events); } unsigned GetReturnedEvents() const { return revents; } void ClearReturnedEvents() { revents = 0; } protected: virtual bool OnSocketReady(unsigned flags) override { revents = flags; multi.SetReady(); return true; } }; friend class SingleFD; bool ready, refresh; std::forward_list fds; public: static constexpr unsigned READ = SocketMonitor::READ; static constexpr unsigned WRITE = SocketMonitor::WRITE; static constexpr unsigned ERROR = SocketMonitor::ERROR; static constexpr unsigned HANGUP = SocketMonitor::HANGUP; MultiSocketMonitor(EventLoop &_loop); ~MultiSocketMonitor(); using IdleMonitor::GetEventLoop; public: /** * Invalidate the socket list. A call to PrepareSockets() is * scheduled which will then update the list. */ void InvalidateSockets() { refresh = true; IdleMonitor::Schedule(); } void AddSocket(int fd, unsigned events) { fds.emplace_front(*this, fd, events); } /** * Remove all sockets. */ void ClearSocketList(); /** * Update the known sockets by invoking the given function for * each one; its return value is the events bit mask. A * return value of 0 means the socket will be removed from the * list. */ template void UpdateSocketList(E &&e) { for (auto prev = fds.before_begin(), end = fds.end(), i = std::next(prev); i != end; i = std::next(prev)) { assert(i->GetEvents() != 0); unsigned events = e(i->GetFD()); if (events != 0) { i->SetEvents(events); prev = i; } else { fds.erase_after(prev); } } } #ifndef WIN32 /** * Replace the socket list with the given file descriptors. * The given pollfd array will be modified by this method. */ void ReplaceSocketList(pollfd *pfds, unsigned n); #endif protected: /** * @return timeout or a negative value for no timeout */ virtual std::chrono::steady_clock::duration PrepareSockets() = 0; virtual void DispatchSockets() = 0; private: void SetReady() { ready = true; IdleMonitor::Schedule(); } void Prepare(); virtual void OnTimeout() final { SetReady(); IdleMonitor::Schedule(); } virtual void OnIdle() final; }; #endif