event/PollGroup: rename to PollBackend

2020-10-19 14:14:32 +02:00
parent c18e00daa4
commit 8348a1ec8f
11 changed files with 63 additions and 63 deletions
@@ -0,0 +1,166 @@
+/*
+ * 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 "WinSelectBackend.hxx"
+#include "WinSelectEvents.hxx"
+
+static constexpr int EVENT_READ = 0;
+static constexpr int EVENT_WRITE = 1;
+
+static constexpr
+bool HasEvent(unsigned events, int event_id) noexcept
+{
+	return (events & (1 << event_id)) != 0;
+}
+
+WinSelectBackend::WinSelectBackend() noexcept = default;
+WinSelectBackend::~WinSelectBackend() noexcept = default;
+
+bool
+WinSelectBackend::CanModify(WinSelectBackend::Item &item,
+			    unsigned events, int event_id) const noexcept
+{
+	if (item.index[event_id] < 0 && HasEvent(events, event_id))
+		return !event_set[event_id].IsFull();
+	return true;
+}
+
+void
+WinSelectBackend::Modify(WinSelectBackend::Item &item, SOCKET fd,
+			 unsigned events, int event_id) noexcept
+{
+	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 (size_t(index) != set.Size() - 1) {
+			set.MoveToEnd(index);
+			items[set[index]].index[event_id] = index;
+		}
+		set.RemoveLast();
+		item.index[event_id] = -1;
+	}
+}
+
+bool
+WinSelectBackend::Add(SOCKET fd, unsigned events, void *obj) noexcept
+{
+	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
+WinSelectBackend::Modify(SOCKET fd, unsigned events, void *obj) noexcept
+{
+	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
+WinSelectBackend::Remove(SOCKET fd) noexcept
+{
+	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;
+}
+
+PollResultGeneric
+WinSelectBackend::ReadEvents(int timeout_ms) noexcept
+{
+	bool use_sleep = event_set[EVENT_READ].IsEmpty() &&
+			 event_set[EVENT_WRITE].IsEmpty();
+
+	PollResultGeneric result;
+	if (use_sleep) {
+		Sleep(timeout_ms < 0 ? INFINITE : (DWORD) timeout_ms);
+		return result;
+	}
+
+	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.GetPtr(),
+			 write_set.GetPtr(),
+			 except_set.GetPtr(),
+			 timeout_ms < 0 ? nullptr : &tv);
+
+	if (ret == 0 || ret == SOCKET_ERROR)
+		return result;
+
+	for (const auto i : read_set)
+		items[i].events |= WinSelectEvents::READ;
+
+	for (const auto i : write_set)
+		items[i].events |= WinSelectEvents::WRITE;
+
+	for (const auto i : except_set)
+		items[i].events |= WinSelectEvents::WRITE;
+
+	for (auto &i : items)
+		if (i.second.events != 0) {
+			result.Add(i.second.events, i.second.obj);
+			i.second.events = 0;
+		}
+
+	return result;
+}