LightSong: new class to be used by DatabasePlugin callbacks

Detach the Song class completely from the public API, only to be used
by SimpleDatabase and the update thread.

1 files changed, 82 insertions, 0 deletions

diff --git a/src/LightSong.hxx b/src/LightSong.hxx
new file mode 100644
index 000000000..b93d5876c
--- /dev/null
+++ b/src/LightSong.hxx
@@ -0,0 +1,82 @@
+/*
+ * 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_LIGHT_SONG_HXX
+#define MPD_LIGHT_SONG_HXX
+
+#include "Compiler.h"
+
+#include <string>
+
+#include <time.h>
+
+struct Tag;
+
+/**
+ * A reference to a song file.  Unlike the other "Song" classes in the
+ * MPD code base, this one consists only of pointers.  It is supposed
+ * to be as light as possible while still providing all the
+ * information MPD has about a song file.  This class does not manage
+ * any memory, and the pointers become invalid quickly.  Only to be
+ * used to pass around during well-defined situations.
+ */
+struct LightSong {
+	/**
+	 * If this is not nullptr, then it denotes a prefix for the
+	 * #uri.  To build the full URI, join directory and uri with a
+	 * slash.
+	 */
+	const char *directory;
+
+	const char *uri;
+
+	/**
+	 * Must not be nullptr.
+	 */
+	const Tag *tag;
+
+	time_t mtime;
+
+	/**
+	 * Start of this sub-song within the file in milliseconds.
+	 */
+	unsigned start_ms;
+
+	/**
+	 * End of this sub-song within the file in milliseconds.
+	 * Unused if zero.
+	 */
+	unsigned end_ms;
+
+	gcc_pure
+	std::string GetURI() const {
+		if (directory == nullptr)
+			return std::string(uri);
+
+		std::string result(directory);
+		result.push_back('/');
+		result.append(uri);
+		return result;
+	}
+
+	gcc_pure
+	double GetDuration() const;
+};
+
+#endif