event: introduce generic API for internal event loop

1 files changed, 91 insertions, 0 deletions

diff --git a/src/event/PollGroupEPoll.hxx b/src/event/PollGroupEPoll.hxx
new file mode 100644
index 000000000..5d50cef93
--- /dev/null
+++ b/src/event/PollGroupEPoll.hxx
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2003-2013 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_EVENT_POLLGROUP_EPOLL_HXX
+#define MPD_EVENT_POLLGROUP_EPOLL_HXX
+
+#include "check.h"
+
+#include "Compiler.h"
+#include "system/EPollFD.hxx"
+
+#include <array>
+#include <algorithm>
+
+class PollResultEPoll
+{
+	friend class PollGroupEPoll;
+
+	std::array<epoll_event, 16> events;
+	int n_events;
+public:
+	PollResultEPoll() : n_events(0) { }
+
+	int GetSize() const { return n_events; }
+	unsigned GetEvents(int i) { return events[i].events; }
+	void *GetObject(int i) { return events[i].data.ptr; }
+	void Reset() { n_events = 0; }
+
+	void Clear(void *obj) {
+		for (int i = 0; i < n_events; ++i)
+			if (events[i].data.ptr == obj)
+				events[i].events = 0;
+	}
+};
+
+class PollGroupEPoll
+{
+	EPollFD epoll;
+
+	PollGroupEPoll(PollGroupEPoll &) = delete;
+	PollGroupEPoll &operator=(PollGroupEPoll &) = delete;
+public:
+	static constexpr unsigned READ = EPOLLIN;
+	static constexpr unsigned WRITE = EPOLLOUT;
+	static constexpr unsigned ERROR = EPOLLERR;
+	static constexpr unsigned HANGUP = EPOLLHUP;
+
+	PollGroupEPoll() = default;
+
+	void ReadEvents(PollResultEPoll &result, int timeout_ms) {
+		int ret = epoll.Wait(result.events.data(), result.events.size(),
+				     timeout_ms);
+		result.n_events = std::max(0, ret);
+	}
+
+	bool Add(int fd, unsigned events, void *obj) {
+		return epoll.Add(fd, events, obj);
+	}
+
+	bool Modify(int fd, unsigned events, void *obj) {
+		return epoll.Modify(fd, events, obj);
+	}
+
+	bool Remove(int fd) {
+		return epoll.Remove(fd);
+	}
+
+	bool Abandon(gcc_unused int fd) {
+		// Nothing to do in this implementation.
+		// Closed descriptors are automatically unregistered.
+		return true;
+	}
+};
+
+#endif