event: implement PollGroup based on Windows select

1 files changed, 158 insertions, 0 deletions

diff --git a/src/event/PollGroupWinSelect.cxx b/src/event/PollGroupWinSelect.cxx
new file mode 100644
index 000000000..1050ffa8a
--- /dev/null
+++ b/src/event/PollGroupWinSelect.cxx
@@ -0,0 +1,158 @@
+/*
+ * 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_WINSELECT
+
+#include "PollGroupWinSelect.hxx"
+
+constexpr int EVENT_READ = 0;
+constexpr int EVENT_WRITE = 1;
+
+static inline bool HasEvent(unsigned events, int event_id)
+{
+	return (events & (1 << event_id)) != 0;
+}
+
+bool PollGroupWinSelect::CanModify(PollGroupWinSelect::Item &item,
+				   unsigned events, int event_id)
+{
+	if (item.index[event_id] < 0 && HasEvent(events, event_id))
+		return !event_set[event_id].IsFull();
+	return true;
+}
+
+void PollGroupWinSelect::Modify(PollGroupWinSelect::Item &item, int fd,
+				unsigned events, int event_id)
+{
+	int index = item.index[event_id];
+	auto &set = event_set[event_id];
+
+	if (index < 0 && HasEvent(events, event_id))
+		item.index[event_id] = set.Add(fd);
+	else if (index >= 0 && !HasEvent(events, event_id)) {
+		if (index != set.Size() - 1) {
+			set.MoveToEnd(index);
+			items[set[index]].index[event_id] = index;
+		}
+		set.RemoveLast();
+		item.index[event_id] = -1;
+	}
+}
+
+bool PollGroupWinSelect::Add(int fd, unsigned events, void *obj)
+{
+	assert(items.find(fd) == items.end());
+	auto &item = items[fd];
+
+	item.index[EVENT_READ] = -1;
+	item.index[EVENT_WRITE] = -1;
+	item.obj = obj;
+	item.events = 0;
+
+	if (!CanModify(item, events, EVENT_READ)) {
+		items.erase(fd);
+		return false;
+	}
+	if (!CanModify(item, events, EVENT_WRITE)) {
+		items.erase(fd);
+		return false;
+	}
+
+	Modify(item, fd, events, EVENT_READ);
+	Modify(item, fd, events, EVENT_WRITE);
+	return true;
+}
+
+bool PollGroupWinSelect::Modify(int fd, unsigned events, void *obj)
+{
+	auto item_iter = items.find(fd);
+	assert(item_iter != items.end());
+	auto &item = item_iter->second;
+
+	if (!CanModify(item, events, EVENT_READ))
+		return false;
+	if (!CanModify(item, events, EVENT_WRITE))
+		return false;
+
+	item.obj = obj;
+	Modify(item, fd, events, EVENT_READ);
+	Modify(item, fd, events, EVENT_WRITE);
+	return true;
+}
+
+bool PollGroupWinSelect::Remove(int fd)
+{
+	auto item_iter = items.find(fd);
+	assert(item_iter != items.end());
+	auto &item = item_iter->second;
+
+	Modify(item, fd, 0, EVENT_READ);
+	Modify(item, fd, 0, EVENT_WRITE);
+	items.erase(item_iter);
+	return true;
+}
+
+void PollGroupWinSelect::ReadEvents(PollResultGeneric &result, int timeout_ms)
+{
+	bool use_sleep = event_set[EVENT_READ].IsEmpty() &&
+			 event_set[EVENT_WRITE].IsEmpty();
+
+	if (use_sleep) {
+		Sleep(timeout_ms < 0 ? INFINITE : (DWORD) timeout_ms);
+		return;
+	}
+
+	SocketSet read_set(event_set[EVENT_READ]);
+	SocketSet write_set(event_set[EVENT_WRITE]);
+	SocketSet except_set(event_set[EVENT_WRITE]);
+
+	timeval tv;
+	if (timeout_ms >= 0) {
+		tv.tv_sec = timeout_ms / 1000;
+		tv.tv_usec = (timeout_ms % 1000) * 1000;
+	}
+
+	int ret = select(0,
+			 read_set.IsEmpty() ? nullptr : read_set.GetPtr(),
+			 write_set.IsEmpty() ? nullptr : write_set.GetPtr(),
+			 except_set.IsEmpty() ? nullptr : except_set.GetPtr(),
+			 timeout_ms < 0 ? nullptr : &tv);
+
+	if (ret == 0 || ret == SOCKET_ERROR)
+		return;
+
+	for (int i = 0; i < read_set.Size(); ++i)
+		items[read_set[i]].events |= READ;
+
+	for (int i = 0; i < write_set.Size(); ++i)
+		items[write_set[i]].events |= WRITE;
+
+	for (int i = 0; i < except_set.Size(); ++i)
+		items[except_set[i]].events |= WRITE;
+
+	for (auto i = items.begin(); i != items.end(); ++i)
+		if (i->second.events != 0) {
+			result.Add(i->second.events, i->second.obj);
+			i->second.events = 0;
+		}
+}
+
+#endif