Faster loading of playlists from the playlist editor

src/mpdpp.cpp

@@ -567,16 +567,18 @@ int Connection::AddSong(const Song &s, int pos)
 	return AddSong((!s.isFromDatabase() ? "file://" : "") + s.getURI(), pos);
 }
 
-void Connection::Add(const std::string &path)
+bool Connection::Add(const std::string &path)
 {
+	bool result;
 	prechecks();
 	if (m_command_list_active)
-		mpd_send_add(m_connection.get(), path.c_str());
+		result = mpd_send_add(m_connection.get(), path.c_str());
 	else
 	{
-		mpd_run_add(m_connection.get(), path.c_str());
+		result = mpd_run_add(m_connection.get(), path.c_str());
 		checkErrors();
 	}
+	return result;
 }
 
 bool Connection::AddRandomTag(mpd_tag_type tag, size_t number, std::mt19937 &rng)
@@ -689,11 +691,12 @@ void Connection::DeletePlaylist(const std::string &name)
 	checkErrors();
 }
 
-void Connection::LoadPlaylist(const std::string &name)
+bool Connection::LoadPlaylist(const std::string &name)
 {
 	prechecksNoCommandsList();
-	mpd_run_load(m_connection.get(), name.c_str());
+	bool result = mpd_run_load(m_connection.get(), name.c_str());
 	checkErrors();
+	return result;
 }
 
 void Connection::SavePlaylist(const std::string &name)

src/mpdpp.h

@@ -548,14 +548,14 @@ struct Connection
 	int AddSong(const Song &, int = -1); // returns id of added song
 	bool AddRandomTag(mpd_tag_type, size_t, std::mt19937 &rng);
 	bool AddRandomSongs(size_t number, const std::string &random_exclude_pattern, std::mt19937 &rng);
-	void Add(const std::string &path);
+	bool Add(const std::string &path);
 	void Delete(unsigned int pos);
 	void PlaylistDelete(const std::string &playlist, unsigned int pos);
 	void StartCommandsList();
 	void CommitCommandsList();
 	
 	void DeletePlaylist(const std::string &name);
-	void LoadPlaylist(const std::string &name);
+	bool LoadPlaylist(const std::string &name);
 	void SavePlaylist(const std::string &);
 	void ClearPlaylist(const std::string &playlist);
 	void AddToPlaylist(const std::string &, const Song &);

src/screens/browser.cpp

@@ -305,14 +305,13 @@ bool Browser::itemAvailable()
 
 bool Browser::addItemToPlaylist(bool play)
 {
-	bool result = false;
+	bool success = false;
 
 	auto tryToPlay = [] {
-		// Cheap trick that might fail in presence of multiple
+		// Cheap trick that might fail in presence of multiple clients modifying the
-		// clients modifying the playlist at the same time, but
+		// playlist at the same time, but oh well, this approach correctly loads cue
-		// oh well, this approach correctly loads cue playlists
+		// playlists and is much faster in general as it doesn't require fetching
-		// and is much faster in general as it doesn't require
+		// song data.
-		// fetching song data.
 		try
 		{
 			Mpd.Play(Status::State::playlistLength());
@@ -334,31 +333,30 @@ bool Browser::addItemToPlaylist(bool play)
 			{
 				std::vector<MPD::Song> songs;
 				getLocalDirectoryRecursively(songs, item.directory().path());
-				result = addSongsToPlaylist(songs.begin(), songs.end(), play, -1);
+				success = addSongsToPlaylist(songs.begin(), songs.end(), play, -1);
 			}
 			else
 			{
-				Mpd.Add(item.directory().path());
+				success = Mpd.Add(item.directory().path());
 				if (play)
 					tryToPlay();
-				result = true;
 			}
 			Statusbar::printf("Directory \"%1%\" added%2%",
-				item.directory().path(), withErrors(result));
+				item.directory().path(), withErrors(success));
 			break;
 		}
 		case MPD::Item::Type::Song:
-			result = addSongToPlaylist(item.song(), play);
+			success = addSongToPlaylist(item.song(), play);
 			break;
 		case MPD::Item::Type::Playlist:
-			Mpd.LoadPlaylist(item.playlist().path());
+			success = Mpd.LoadPlaylist(item.playlist().path());
 			if (play)
 				tryToPlay();
+			if (success)
 				Statusbar::printf("Playlist \"%1%\" loaded", item.playlist().path());
-			result = true;
 			break;
 	}
-	return result;
+	return success;
 }
 
 std::vector<MPD::Song> Browser::getSelectedSongs()

src/screens/playlist_editor.cpp

@@ -374,17 +374,34 @@ bool PlaylistEditor::itemAvailable()
 
 bool PlaylistEditor::addItemToPlaylist(bool play)
 {
-	bool result = false;
+	bool success = false;
 	if (isActiveWindow(Playlists))
 	{
-		ScopedUnfilteredMenu<MPD::Song> sunfilter_content(ReapplyFilter::No, Content);
+		const auto &playlist = Playlists.current()->value();
-		result = addSongsToPlaylist(Content.beginV(), Content.endV(), play, -1);
+		success = Mpd.LoadPlaylist(playlist.path());
-		Statusbar::printf("Playlist \"%1%\" loaded%2%",
+		if (play)
-		                  Playlists.current()->value().path(), withErrors(result));
+		{
+			// Cheap trick that might fail in presence of multiple clients modifying the
+			// playlist at the same time, but oh well, this approach correctly loads cue
+			// playlists and is much faster in general as it doesn't require fetching
+			// song data.
+			try
+			{
+				Mpd.Play(Status::State::playlistLength());
+			}
+			catch (MPD::ServerError &e)
+			{
+				// If not bad index, rethrow.
+				if (e.code() != MPD_SERVER_ERROR_ARG)
+					throw;
+			}
+		}
+		if (success)
+			Statusbar::printf("Playlist \"%1%\" loaded", playlist.path());
 	}
 	else if (isActiveWindow(Content))
-		result = addSongToPlaylist(Content.current()->value(), play);
+		success = addSongToPlaylist(Content.current()->value(), play);
-	return result;
+	return success;
 }
 
 std::vector<MPD::Song> PlaylistEditor::getSelectedSongs()