Optimize deletion/cropping of main playlist by using ranges

src/actions.cpp

@@ -681,8 +681,7 @@ void DeletePlaylistItems::run()
 	if (myScreen == myPlaylist)
 	{
 		Statusbar::print("Deleting items...");
-		auto delete_fun = std::bind(&MPD::Connection::Delete, ph::_1, ph::_2);
-		deleteSelectedSongs(myPlaylist->main(), delete_fun);
+		deleteSelectedSongsFromPlaylist(myPlaylist->main());
 		Statusbar::print("Item(s) deleted");
 	}
 	else if (myScreen->isActiveWindow(myPlaylistEditor->Content))
@@ -1926,7 +1925,8 @@ void CropMainPlaylist::run()
 		confirmAction("Do you really want to crop main playlist?");
 	Statusbar::print("Cropping playlist...");
 	selectCurrentIfNoneSelected(w);
-	cropPlaylist(w, std::bind(&MPD::Connection::Delete, ph::_1, ph::_2));
+	reverseSelectionHelper(w.begin(), w.end());
+	deleteSelectedSongsFromPlaylist(w);
 	Statusbar::print("Playlist cropped");
 }
 

src/helpers.cpp

@@ -76,6 +76,30 @@ MPD::SongIterator getDatabaseIterator(MPD::Connection &mpd)
 	return result;
 }
 
+void deleteSelectedSongsFromPlaylist(NC::Menu<MPD::Song> &playlist)
+{
+	selectCurrentIfNoneSelected(playlist);
+	boost::optional<int> range_end;
+	Mpd.StartCommandsList();
+	for (auto &s : boost::adaptors::reverse(playlist))
+	{
+		if (s.isSelected())
+		{
+			s.setSelected(false);
+			if (range_end == boost::none)
+				range_end = s.value().getPosition() + 1;
+		}
+		else if (range_end != boost::none)
+		{
+			Mpd.DeleteRange(s.value().getPosition() + 1, *range_end);
+			range_end.reset();
+		}
+	}
+	if (range_end != boost::none)
+		Mpd.DeleteRange(0, *range_end);
+	Mpd.CommitCommandsList();
+}
+
 void removeSongFromPlaylist(const SongMenu &playlist, const MPD::Song &s)
 {
 	Mpd.StartCommandsList();

src/helpers.h

@@ -528,6 +528,8 @@ inline const char *withErrors(bool success)
 	return success ? "" : " " "(with errors)";
 }
 
+void deleteSelectedSongsFromPlaylist(NC::Menu<MPD::Song> &playlist);
+
 bool addSongToPlaylist(const MPD::Song &s, bool play, int position = -1);
 
 const MPD::Song *currentSong(const BaseScreen *screen);

src/mpdpp.cpp

@@ -655,6 +655,17 @@ void Connection::Delete(unsigned pos)
 	}
 }
 
+void Connection::DeleteRange(unsigned begin, unsigned end)
+{
+	prechecks();
+	mpd_send_delete_range(m_connection.get(), begin, end);
+	if (!m_command_list_active)
+	{
+		mpd_response_finish(m_connection.get());
+		checkErrors();
+	}
+}
+
 void Connection::PlaylistDelete(const std::string &playlist, unsigned pos)
 {
 	prechecks();

src/mpdpp.h

@@ -550,6 +550,7 @@ struct Connection
 	bool AddRandomSongs(size_t number, const std::string &random_exclude_pattern, std::mt19937 &rng);
 	bool Add(const std::string &path);
 	void Delete(unsigned int pos);
+	void DeleteRange(unsigned begin, unsigned end);
 	void PlaylistDelete(const std::string &playlist, unsigned int pos);
 	void StartCommandsList();
 	void CommitCommandsList();