input/nfs: use the asynchronous libnfs API

More robust and cancellable.

src/lib/nfs/Manager.cxx

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2003-2014 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"
+#include "Manager.hxx"
+#include "event/Loop.hxx"
+#include "Log.hxx"
+
+void
+NfsManager::ManagedConnection::OnNfsConnectionError(Error &&error)
+{
+	FormatError(error, "NFS error on %s:%s", GetServer(), GetExportName());
+
+	manager.connections.erase(Key(GetServer(), GetExportName()));
+}
+
+NfsConnection &
+NfsManager::GetConnection(const char *server, const char *export_name)
+{
+	assert(server != nullptr);
+	assert(export_name != nullptr);
+	assert(loop.IsInside());
+
+	const std::string key = Key(server, export_name);
+
+	auto e = connections.emplace(std::piecewise_construct,
+				     std::forward_as_tuple(key),
+				     std::forward_as_tuple(*this, loop,
+							   server,
+							   export_name));
+	return e.first->second;
+}