new feature: custom command execution on song change

src/settings.cpp

@@ -533,6 +533,11 @@ void ReadConfiguration(ncmpcpp_config &conf)
 				if (!v.empty())
 					conf.system_encoding = v + "//TRANSLIT";
 			}
+			else if (cl.find("execute_on_song_change") != string::npos)
+			{
+				if (!v.empty())
+					conf.execute_on_song_change = v;
+			}
 			else if (cl.find("browser_playlist_prefix") != string::npos)
 			{
 				if (!v.empty())

src/settings.h

@@ -119,6 +119,7 @@ struct ncmpcpp_config
 	std::string tag_editor_album_format;
 	std::string external_editor;
 	std::string system_encoding;
+	std::string execute_on_song_change;
 	
 	std::string pattern;
 	

src/status.cpp

@@ -343,6 +343,8 @@ void NcmpcppStatusChanged(Connection *Mpd, StatusChanges changed, void *)
 		if (myPlaylist->isPlaying())
 		{
 			np = Mpd->GetCurrentSong();
+			if (!Config.execute_on_song_change.empty())
+				system(np.toString(Config.execute_on_song_change).c_str());
 			if (Mpd->GetState() > psStop)
 				WindowTitle(utf_to_locale_cpy(np.toString(Config.song_window_title_format)));
 			if (Config.autocenter_mode && !myPlaylist->Main()->isFiltered())