input/nfs: use the asynchronous libnfs API

More robust and cancellable.

src/lib/nfs/Manager.hxx

@@ -0,0 +1,72 @@
+/*
+ * 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.
+ */
+
+#ifndef MPD_NFS_MANAGER_HXX
+#define MPD_NFS_MANAGER_HXX
+
+#include "check.h"
+#include "Connection.hxx"
+
+#include <string>
+#include <map>
+
+/**
+ * A manager for NFS connections.  Handles multiple connections to
+ * multiple NFS servers.
+ */
+class NfsManager {
+	class ManagedConnection final : public NfsConnection {
+		NfsManager &manager;
+
+	public:
+		ManagedConnection(NfsManager &_manager, EventLoop &_loop,
+				  const char *_server,
+				  const char *_export_name)
+			:NfsConnection(_loop, _server, _export_name),
+			 manager(_manager) {}
+
+	protected:
+		/* virtual methods from NfsConnection */
+		void OnNfsConnectionError(Error &&error) override;
+	};
+
+	EventLoop &loop;
+
+	/**
+	 * Maps server+":"+export_name (see method Key()) to
+	 * #ManagedConnection.
+	 */
+	std::map<std::string, ManagedConnection> connections;
+
+public:
+	NfsManager(EventLoop &_loop)
+		:loop(_loop) {}
+
+	gcc_pure
+	NfsConnection &GetConnection(const char *server,
+				     const char *export_name);
+
+private:
+	gcc_pure
+	static std::string Key(const char *server, const char *export_name) {
+		return std::string(server) + ':' + export_name;
+	}
+};
+
+#endif