playlist_plugin: new plugin API for playlist parsers

Based on this API, we will add parsers for EXTM3U, PLS, ASX, last.fm
radio and others.

There is no integration into the MPD core yet.  Right now, we have a
command line test program.  This is work in progress.

1 files changed, 137 insertions, 0 deletions

diff --git a/src/playlist_plugin.h b/src/playlist_plugin.h
new file mode 100644
index 000000000..3515af109
--- /dev/null
+++ b/src/playlist_plugin.h
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2003-2009 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_PLAYLIST_PLUGIN_H
+#define MPD_PLAYLIST_PLUGIN_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+struct config_param;
+struct input_stream;
+struct tag;
+
+/**
+ * An object which provides the contents of a playlist.
+ */
+struct playlist_provider {
+	const struct playlist_plugin *plugin;
+};
+
+static inline void
+playlist_provider_init(struct playlist_provider *playlist,
+		       const struct playlist_plugin *plugin)
+{
+	playlist->plugin = plugin;
+}
+
+struct playlist_plugin {
+	const char *name;
+
+	/**
+	 * Initialize the plugin.  Optional method.
+	 *
+	 * @param param a configuration block for this plugin, or NULL
+	 * if none is configured
+	 * @return true if the plugin was initialized successfully,
+	 * false if the plugin is not available
+	 */
+	bool (*init)(const struct config_param *param);
+
+	/**
+	 * Deinitialize a plugin which was initialized successfully.
+	 * Optional method.
+	 */
+	void (*finish)(void);
+
+	/**
+	 * Opens the playlist on the specified URI.  This URI has
+	 * either matched one of the schemes or one of the suffixes.
+	 */
+	struct playlist_provider *(*open_uri)(const char *uri);
+
+	/**
+	 * Opens the playlist in the specified input stream.  It has
+	 * either matched one of the suffixes or one of the MIME
+	 * types.
+	 */
+	struct playlist_provider *(*open_stream)(struct input_stream *is);
+
+	void (*close)(struct playlist_provider *playlist);
+
+	struct song *(*read)(struct playlist_provider *playlist);
+
+	const char *const*schemes;
+	const char *const*suffixes;
+	const char *const*mime_types;
+};
+
+/**
+ * Initialize a plugin.
+ *
+ * @param param a configuration block for this plugin, or NULL if none
+ * is configured
+ * @return true if the plugin was initialized successfully, false if
+ * the plugin is not available
+ */
+static inline bool
+playlist_plugin_init(const struct playlist_plugin *plugin,
+		     const struct config_param *param)
+{
+	return plugin->init != NULL
+		? plugin->init(param)
+		: true;
+}
+
+/**
+ * Deinitialize a plugin which was initialized successfully.
+ */
+static inline void
+playlist_plugin_finish(const struct playlist_plugin *plugin)
+{
+	if (plugin->finish != NULL)
+		plugin->finish();
+}
+
+static inline struct playlist_provider *
+playlist_plugin_open_uri(const struct playlist_plugin *plugin, const char *uri)
+{
+	return plugin->open_uri(uri);
+}
+
+static inline struct playlist_provider *
+playlist_plugin_open_stream(const struct playlist_plugin *plugin,
+			    struct input_stream *is)
+{
+	return plugin->open_stream(is);
+}
+
+static inline void
+playlist_plugin_close(struct playlist_provider *playlist)
+{
+	playlist->plugin->close(playlist);
+}
+
+static inline struct song *
+playlist_plugin_read(struct playlist_provider *playlist)
+{
+	return playlist->plugin->read(playlist);
+}
+
+#endif