event: add poll() based PollGroup implementation

1 files changed, 88 insertions, 0 deletions

diff --git a/src/event/PollGroupPoll.cxx b/src/event/PollGroupPoll.cxx
new file mode 100644
index 000000000..a2b4d1d88
--- /dev/null
+++ b/src/event/PollGroupPoll.cxx
@@ -0,0 +1,88 @@
+/*
+ * 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.
+ */
+
+#include "config.h"
+
+#ifdef USE_POLL
+
+#include "PollGroupPoll.hxx"
+
+#include <assert.h>
+
+PollGroupPoll::PollGroupPoll() { }
+PollGroupPoll::~PollGroupPoll() { }
+
+bool PollGroupPoll::Add(int fd, unsigned events, void *obj)
+{
+	assert(items.find(fd) == items.end());
+	poll_events.resize(poll_events.size() + 1);
+	size_t index = poll_events.size() - 1;
+	auto &e = poll_events[index];
+	e.fd = fd;
+	e.events = events;
+	e.revents = 0;
+	auto &item = items[fd];
+	item.index = index;
+	item.obj = obj;
+	return true;
+}
+
+bool PollGroupPoll::Modify(int fd, unsigned events, void *obj)
+{
+	auto item_iter = items.find(fd);
+	assert(item_iter != items.end());
+	auto &item = item_iter->second;
+	item.obj = obj;
+	auto &e = poll_events[item.index];
+	e.events = events;
+	e.revents &= events;
+	return true;
+}
+
+bool PollGroupPoll::Remove(int fd)
+{
+	auto item_iter = items.find(fd);
+	assert(item_iter != items.end());
+	auto &item = item_iter->second;
+	size_t index = item.index;
+	size_t last_index = poll_events.size() - 1;
+	if (index != last_index) {
+		std::swap(poll_events[index], poll_events[last_index]);
+		items[poll_events[index].fd].index = index;
+	}
+	poll_events.pop_back();
+	items.erase(item_iter);
+	return true;
+}
+
+void PollGroupPoll::ReadEvents(PollResultGeneric &result, int timeout_ms)
+{
+	int n = poll(poll_events.empty() ? nullptr : &poll_events[0],
+		     poll_events.size(), timeout_ms);
+
+	for (size_t i = 0; n > 0 && i < poll_events.size(); ++i) {
+		const auto &e = poll_events[i];
+		if (e.revents != 0) {
+			result.Add(e.revents, items[e.fd].obj);
+			--n;
+		}
+	}
+}
+
+#endif