Instance: add GetDatabaseOrThrow()

src/Instance.cxx

@@ -44,6 +44,16 @@ Instance::GetDatabase(Error &error)
 	return database;
 }
 
+const Database &
+Instance::GetDatabaseOrThrow() const
+{
+	if (database == nullptr)
+		throw DatabaseError(DatabaseErrorCode::DISABLED,
+				    "No database");
+
+	return *database;
+}
+
 void
 Instance::OnDatabaseModified()
 {

src/Instance.hxx

@@ -110,6 +110,14 @@ struct Instance final
 	 * music_directory was configured).
 	 */
 	Database *GetDatabase(Error &error);
+
+	/**
+	 * Returns the global #Database instance.  Throws
+	 * DatabaseError if this MPD configuration has no database (no
+	 * music_directory was configured).
+	 */
+	gcc_pure
+	const Database &GetDatabaseOrThrow() const;
 #endif
 
 private:

src/Partition.cxx

@@ -50,6 +50,12 @@ Partition::GetDatabase(Error &error) const
 	return instance.GetDatabase(error);
 }
 
+const Database &
+Partition::GetDatabaseOrThrow() const
+{
+	return instance.GetDatabaseOrThrow();
+}
+
 void
 Partition::DatabaseModified(const Database &db)
 {

src/Partition.hxx

@@ -185,6 +185,9 @@ struct Partition final : QueueListener, PlayerListener, MixerListener {
 	 */
 	const Database *GetDatabase(Error &error) const;
 
+	gcc_pure
+	const Database &GetDatabaseOrThrow() const;
+
 	/**
 	 * The database has been modified.  Propagate the change to
 	 * all subsystems.

src/client/Client.cxx

@@ -33,6 +33,12 @@ Client::GetDatabase(Error &error) const
 	return partition.instance.GetDatabase(error);
 }
 
+const Database &
+Client::GetDatabaseOrThrow() const
+{
+	return partition.instance.GetDatabaseOrThrow();
+}
+
 const Storage *
 Client::GetStorage() const
 {

src/client/Client.hxx

@@ -187,6 +187,12 @@ public:
 	gcc_pure
 	const Database *GetDatabase(Error &error) const;
 
+	/**
+	 * Wrapper for Instance::GetDatabaseOrThrow().
+	 */
+	gcc_pure
+	const Database &GetDatabaseOrThrow() const;
+
 	gcc_pure
 	const Storage *GetStorage() const;
 

src/command/DatabaseCommands.cxx

@@ -143,11 +143,9 @@ handle_searchaddpl(Client &client, Request args, Response &r)
 	}
 
 	Error error;
-	const Database *db = client.GetDatabase(error);
+	const Database &db = client.GetDatabaseOrThrow();
-	if (db == nullptr)
-		return print_error(r, error);
 
-	return search_add_to_playlist(*db, *client.GetStorage(),
+	return search_add_to_playlist(db, *client.GetStorage(),
 				      "", playlist, &filter, error)
 		? CommandResult::OK
 		: print_error(r, error);

src/command/PlaylistCommands.cxx

@@ -168,11 +168,9 @@ handle_playlistadd(Client &client, Request args, Response &r)
 		success = spl_append_uri(playlist, loader, uri, error);
 	} else {
 #ifdef ENABLE_DATABASE
-		const Database *db = client.GetDatabase(error);
+		const Database &db = client.GetDatabaseOrThrow();
-		if (db == nullptr)
-			return print_error(r, error);
 
-		success = search_add_to_playlist(*db, *client.GetStorage(),
+		success = search_add_to_playlist(db, *client.GetStorage(),
 						 uri, playlist, nullptr,
 						 error);
 #else

src/command/StickerCommands.cxx

@@ -54,19 +54,17 @@ static CommandResult
 handle_sticker_song(Response &r, Partition &partition, Request args)
 {
 	Error error;
-	const Database *db = partition.GetDatabase(error);
+	const Database &db = partition.GetDatabaseOrThrow();
-	if (db == nullptr)
-		return print_error(r, error);
 
 	const char *const cmd = args.front();
 
 	/* get song song_id key */
 	if (args.size == 4 && StringIsEqual(cmd, "get")) {
-		const LightSong *song = db->GetSong(args[2]);
+		const LightSong *song = db.GetSong(args[2]);
 
 		const auto value = sticker_song_get_value(*song, args[3],
 							  error);
-		db->ReturnSong(song);
+		db.ReturnSong(song);
 		if (value.empty()) {
 			if (error.IsDefined())
 				return print_error(r, error);
@@ -80,11 +78,11 @@ handle_sticker_song(Response &r, Partition &partition, Request args)
 		return CommandResult::OK;
 	/* list song song_id */
 	} else if (args.size == 3 && StringIsEqual(cmd, "list")) {
-		const LightSong *song = db->GetSong(args[2]);
+		const LightSong *song = db.GetSong(args[2]);
 		assert(song != nullptr);
 
 		Sticker *sticker = sticker_song_get(*song, error);
-		db->ReturnSong(song);
+		db.ReturnSong(song);
 		if (sticker) {
 			sticker_print(r, *sticker);
 			sticker_free(sticker);
@@ -94,12 +92,12 @@ handle_sticker_song(Response &r, Partition &partition, Request args)
 		return CommandResult::OK;
 	/* set song song_id id key */
 	} else if (args.size == 5 && StringIsEqual(cmd, "set")) {
-		const LightSong *song = db->GetSong(args[2]);
+		const LightSong *song = db.GetSong(args[2]);
 		assert(song != nullptr);
 
 		bool ret = sticker_song_set_value(*song, args[3], args[4],
 						  error);
-		db->ReturnSong(song);
+		db.ReturnSong(song);
 		if (!ret) {
 			if (error.IsDefined())
 				return print_error(r, error);
@@ -113,13 +111,13 @@ handle_sticker_song(Response &r, Partition &partition, Request args)
 	/* delete song song_id [key] */
 	} else if ((args.size == 3 || args.size == 4) &&
 		   StringIsEqual(cmd, "delete")) {
-		const LightSong *song = db->GetSong(args[2]);
+		const LightSong *song = db.GetSong(args[2]);
 		assert(song != nullptr);
 
 		bool ret = args.size == 3
 			? sticker_song_delete(*song, error)
 			: sticker_song_delete_value(*song, args[3], error);
-		db->ReturnSong(song);
+		db.ReturnSong(song);
 		if (!ret) {
 			if (error.IsDefined())
 				return print_error(r, error);
@@ -163,7 +161,7 @@ handle_sticker_song(Response &r, Partition &partition, Request args)
 			args[3],
 		};
 
-		if (!sticker_song_find(*db, base_uri, data.name,
+		if (!sticker_song_find(db, base_uri, data.name,
 				       op, value,
 				       sticker_song_find_print_cb, &data,
 				       error)) {

src/db/Count.cxx

@@ -113,9 +113,7 @@ PrintSongCount(Response &r, const Partition &partition, const char *name,
 	       TagType group,
 	       Error &error)
 {
-	const Database *db = partition.GetDatabase(error);
+	const Database &db = partition.GetDatabaseOrThrow();
-	if (db == nullptr)
-		return false;
 
 	const DatabaseSelection selection(name, true, filter);
 
@@ -127,7 +125,7 @@ PrintSongCount(Response &r, const Partition &partition, const char *name,
 		using namespace std::placeholders;
 		const auto f = std::bind(stats_visitor_song, std::ref(stats),
 					 _1);
-		if (!db->Visit(selection, f, error))
+		if (!db.Visit(selection, f, error))
 			return false;
 
 		PrintSearchStats(r, stats);
@@ -140,7 +138,7 @@ PrintSongCount(Response &r, const Partition &partition, const char *name,
 		using namespace std::placeholders;
 		const auto f = std::bind(GroupCountVisitor, std::ref(map),
 					 group, _1);
-		if (!db->Visit(selection, f, error))
+		if (!db.Visit(selection, f, error))
 			return false;
 
 		Print(r, group, map);

src/db/DatabasePrint.cxx

@@ -155,9 +155,7 @@ db_selection_print(Response &r, Partition &partition,
 		   unsigned window_start, unsigned window_end,
 		   Error &error)
 {
-	const Database *db = partition.GetDatabase(error);
+	const Database &db = partition.GetDatabaseOrThrow();
-	if (db == nullptr)
-		return false;
 
 	unsigned i = 0;
 
@@ -182,7 +180,7 @@ db_selection_print(Response &r, Partition &partition,
 			return !in_window || s(song, error2);
 		};
 
-	return db->Visit(selection, d, s, p, error);
+	return db.Visit(selection, d, s, p, error);
 }
 
 bool
@@ -226,9 +224,7 @@ PrintUniqueTags(Response &r, Partition &partition,
 		const SongFilter *filter,
 		Error &error)
 {
-	const Database *db = partition.GetDatabase(error);
+	const Database &db = partition.GetDatabaseOrThrow();
-	if (db == nullptr)
-		return false;
 
 	const DatabaseSelection selection("", true, filter);
 
@@ -236,15 +232,15 @@ PrintUniqueTags(Response &r, Partition &partition,
 		using namespace std::placeholders;
 		const auto f = std::bind(PrintSongURIVisitor,
 					 std::ref(r), std::ref(partition), _1);
-		return db->Visit(selection, f, error);
+		return db.Visit(selection, f, error);
 	} else {
 		assert(type < TAG_NUM_OF_ITEM_TYPES);
 
 		using namespace std::placeholders;
 		const auto f = std::bind(PrintUniqueTag, std::ref(r),
 					 (TagType)type, _1);
-		return db->VisitUniqueTags(selection, (TagType)type,
+		return db.VisitUniqueTags(selection, (TagType)type,
-					   group_mask,
+					  group_mask,
-					   f, error);
+					  f, error);
 	}
 }

src/db/DatabaseQueue.cxx

@@ -41,11 +41,9 @@ bool
 AddFromDatabase(Partition &partition, const DatabaseSelection &selection,
 		Error &error)
 {
-	const Database *db = partition.instance.GetDatabase(error);
+	const Database &db = partition.instance.GetDatabaseOrThrow();
-	if (db == nullptr)
-		return false;
 
 	using namespace std::placeholders;
 	const auto f = std::bind(AddToQueue, std::ref(partition), _1);
-	return db->Visit(selection, f, error);
+	return db.Visit(selection, f, error);
 }