mapper: make the music_directory optional

Without a music_directory, MPD is an excellent streaming client.

NEWS

@@ -12,7 +12,7 @@ ver 0.15 - (200?/??/??)
 * failure to read the state file is non-fatal
 * added Icy-Metadata support
 * --create-db starts the MPD daemon instead of exiting
-* playlist_directory is optional
+* playlist_directory and music_directory are optional
 
 
 ver 0.14.1 (2009/01/17)

doc/mpd.conf.5

@@ -29,9 +29,6 @@ See \fBdocs/mpdconf.example\fP in the source tarball for an example
 configuration file.
 .SH REQUIRED PARAMETERS
 .TP
-.B music_directory <directory>
-This specifies the directory where music is located.
-.TP
 .B follow_outside_symlinks <yes or no>
 Control if MPD will follow symbolic links pointing outside the music dir.
 You must recreate the database after changing this option.
@@ -54,6 +51,10 @@ The special value "syslog" makes MPD use the local syslog daemon.
 .B pid_file <file>
 This specifies the file to save mpd's process ID in.
 .TP
+.B music_directory <directory>
+This specifies the directory where music is located.
+If you do not configure this, you can only play streams.
+.TP
 .B playlist_directory <directory>
 This specifies the directory where saved playlists are stored.
 If you do not configure this, you cannot save playlists.

src/database.c

@@ -49,12 +49,16 @@ db_init(const char *path)
 {
 	database_path = g_strdup(path);
 
+	if (path != NULL)
 		music_root = directory_new("", NULL);
 }
 
 void
 db_finish(void)
 {
+	assert((database_path == NULL) == (music_root == NULL));
+
+	if (music_root != NULL)
 		directory_free(music_root);
 
 	g_free(database_path);
@@ -63,6 +67,8 @@ db_finish(void)
 void
 db_clear(void)
 {
+	assert(music_root != NULL);
+
 	directory_free(music_root);
 	music_root = directory_new("", NULL);
 }
@@ -78,6 +84,9 @@ db_get_root(void)
 struct directory *
 db_get_directory(const char *name)
 {
+	if (music_root == NULL)
+		return NULL;
+
 	if (name == NULL)
 		return music_root;
 
@@ -89,14 +98,20 @@ db_get_song(const char *file)
 {
 	struct song *song = NULL;
 	struct directory *directory;
-	char *dir = NULL;
-	char *duplicated = g_strdup(file);
-	char *shortname = strrchr(duplicated, '/');
+	char *duplicated, *shortname, *dir;
+
+	assert(file != NULL);
 
 	g_debug("get song: %s", file);
 
+	if (music_root == NULL)
+		return NULL;
+
+	duplicated = g_strdup(file);
+	shortname = strrchr(duplicated, '/');
 	if (!shortname) {
 		shortname = duplicated;
+		dir = NULL;
 	} else {
 		*shortname = '\0';
 		++shortname;
@@ -121,6 +136,9 @@ db_walk(const char *name,
 {
 	struct directory *directory;
 
+	if (music_root == NULL)
+		return -1;
+
 	if ((directory = db_get_directory(name)) == NULL) {
 		struct song *song;
 		if ((song = db_get_song(name)) && forEachSong) {

src/database.h

@@ -42,6 +42,10 @@ db_finish(void);
 void
 db_clear(void);
 
+/**
+ * Returns the root directory object.  Returns NULL if there is no
+ * configured music directory.
+ */
 struct directory *
 db_get_root(void);
 

src/main.c

@@ -128,7 +128,16 @@ static void openDB(Options * options, char *argv0)
 {
 	struct config_param *param;
 
-	param = parseConfigFilePath(CONF_DB_FILE, true);
+	param = parseConfigFilePath(CONF_DB_FILE,
+				    mapper_has_music_directory());
+	if (!mapper_has_music_directory()) {
+		if (param != NULL)
+			g_message("Found " CONF_DB_FILE " setting without "
+				  CONF_MUSIC_DIR " - disabling database");
+		db_init(NULL);
+		return;
+	}
+
 	db_init(param->value);
 
 	if (options->createDB > 0 || !db_load()) {

src/mapper.c

@@ -40,6 +40,24 @@ static size_t music_dir_length;
 
 static char *playlist_dir;
 
+static void
+mapper_set_music_dir(const char *path, int line)
+{
+	int ret;
+	struct stat st;
+
+	music_dir = g_strdup(path);
+	music_dir_length = strlen(music_dir);
+
+	ret = stat(music_dir, &st);
+	if (ret < 0)
+		g_warning("failed to stat music directory \"%s\" (config line %i): %s\n",
+			  music_dir, line, g_strerror(errno));
+	else if (!S_ISDIR(st.st_mode))
+		g_warning("music directory is not a directory: \"%s\" (config line %i)\n",
+			  music_dir, line);
+}
+
 static void
 mapper_set_playlist_dir(const char *path, int line)
 {
@@ -59,34 +77,19 @@ mapper_set_playlist_dir(const char *path, int line)
 
 void mapper_init(void)
 {
-	struct config_param *music_dir_param =
-		parseConfigFilePath(CONF_MUSIC_DIR, false);
 	struct config_param *param;
-	int ret;
-	struct stat st;
 
-	if (music_dir_param != NULL) {
-		music_dir = g_strdup(music_dir_param->value);
-	} else {
+	param = parseConfigFilePath(CONF_MUSIC_DIR, false);
+	if (param != NULL)
+		mapper_set_music_dir(param->value, param->line);
 #if GLIB_MAJOR_VERSION > 2 || (GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION >= 14)
-		music_dir = g_strdup(g_get_user_special_dir(G_USER_DIRECTORY_MUSIC));
-		if (music_dir == NULL)
-			/* GLib failed to determine the XDG music
-			   directory - abort */
-#endif
-			g_error("config parameter \"%s\" not found\n", CONF_MUSIC_DIR);
+	else {
+		const char *path =
+			g_get_user_special_dir(G_USER_DIRECTORY_MUSIC);
+		if (path != NULL)
+			mapper_set_music_dir(path, -1);
 	}
-
-	music_dir_length = strlen(music_dir);
-
-	ret = stat(music_dir, &st);
-	if (ret < 0)
-		g_warning("failed to stat music directory \"%s\" (config line %i): %s\n",
-			  music_dir_param->value, music_dir_param->line,
-			  strerror(errno));
-	else if (!S_ISDIR(st.st_mode))
-		g_warning("music directory is not a directory: \"%s\" (config line %i)\n",
-			  music_dir_param->value, music_dir_param->line);
+#endif
 
 	param = parseConfigFilePath(CONF_PLAYLIST_DIR, false);
 	if (param != NULL)
@@ -99,6 +102,12 @@ void mapper_finish(void)
 	g_free(playlist_dir);
 }
 
+bool
+mapper_has_music_directory(void)
+{
+	return music_dir != NULL;
+}
+
 char *
 map_uri_fs(const char *uri)
 {
@@ -107,6 +116,9 @@ map_uri_fs(const char *uri)
 	assert(uri != NULL);
 	assert(*uri != '/');
 
+	if (music_dir == NULL)
+		return NULL;
+
 	uri_fs = utf8_to_fs_charset(uri);
 	if (uri_fs == NULL)
 		return NULL;
@@ -120,6 +132,8 @@ map_uri_fs(const char *uri)
 char *
 map_directory_fs(const struct directory *directory)
 {
+	assert(music_dir != NULL);
+
 	if (directory_is_root(directory))
 		return g_strdup(music_dir);
 
@@ -131,6 +145,8 @@ map_directory_child_fs(const struct directory *directory, const char *name)
 {
 	char *name_fs, *parent_fs, *path;
 
+	assert(music_dir != NULL);
+
 	/* check for invalid or unauthorized base names */
 	if (*name == 0 || strchr(name, '/') != NULL ||
 	    strcmp(name, ".") == 0 || strcmp(name, "..") == 0)
@@ -167,7 +183,8 @@ map_song_fs(const struct song *song)
 char *
 map_fs_to_utf8(const char *path_fs)
 {
-	if (strncmp(path_fs, music_dir, music_dir_length) == 0 &&
+	if (music_dir != NULL &&
+	    strncmp(path_fs, music_dir, music_dir_length) == 0 &&
 	    path_fs[music_dir_length] == '/')
 		/* remove musicDir prefix */
 		path_fs += music_dir_length + 1;

src/mapper.h

@@ -23,6 +23,8 @@
 #ifndef MPD_MAPPER_H
 #define MPD_MAPPER_H
 
+#include <stdbool.h>
+
 #define PLAYLIST_FILE_SUFFIX "m3u"
 
 struct directory;
@@ -32,6 +34,12 @@ void mapper_init(void);
 
 void mapper_finish(void);
 
+/**
+ * Returns true if a music directory was configured.
+ */
+bool
+mapper_has_music_directory(void);
+
 /**
  * Determines the absolute file system path of a relative URI.  This
  * is basically done by converting the URI to the file system charset

src/update.c

@@ -680,6 +680,9 @@ directory_update_init(char *path)
 {
 	assert(g_thread_self() == main_task);
 
+	if (!mapper_has_music_directory())
+		return 0;
+
 	if (progress != UPDATE_PROGRESS_IDLE) {
 		unsigned next_task_id;