db/upnp: move lazy Open() call to new class LazyDatabase

Generic approach for the workaround.

1 files changed, 69 insertions, 0 deletions

diff --git a/src/db/LazyDatabase.hxx b/src/db/LazyDatabase.hxx
new file mode 100644
index 000000000..3910cb7fa
--- /dev/null
+++ b/src/db/LazyDatabase.hxx
@@ -0,0 +1,69 @@
+/*
+ * 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.
+ */
+
+#ifndef MPD_LAZY_DATABASE_PLUGIN_HXX
+#define MPD_LAZY_DATABASE_PLUGIN_HXX
+
+#include "DatabasePlugin.hxx"
+
+/**
+ * A wrapper for a #Database object that gets opened on the first
+ * database access.  This works around daemonization problems with
+ * some plugins.
+ */
+class LazyDatabase final : public Database {
+	Database *const db;
+
+	mutable bool open;
+
+public:
+	gcc_nonnull_all
+	LazyDatabase(Database *_db)
+		:db(_db), open(false) {}
+
+	virtual ~LazyDatabase();
+
+	virtual void Close() override;
+
+	virtual Song *GetSong(const char *uri_utf8,
+			      Error &error) const override;
+	virtual void ReturnSong(Song *song) const;
+
+	virtual bool Visit(const DatabaseSelection &selection,
+			   VisitDirectory visit_directory,
+			   VisitSong visit_song,
+			   VisitPlaylist visit_playlist,
+			   Error &error) const override;
+
+	virtual bool VisitUniqueTags(const DatabaseSelection &selection,
+				     TagType tag_type,
+				     VisitString visit_string,
+				     Error &error) const override;
+
+	virtual bool GetStats(const DatabaseSelection &selection,
+			      DatabaseStats &stats,
+			      Error &error) const override;
+
+	virtual time_t GetUpdateStamp() const override;
+
+private:
+	bool EnsureOpen(Error &error) const;
+};
+
+#endif