make function 'clear' in playlist editor clear selected playlist

src/help.cpp

@@ -238,6 +238,7 @@ void Help::GetKeybindings()
 #	endif // ! HAVE_TAGLIB_H
 	*w << DisplayKeys(Key.MvSongUp) << "Move item(s) up\n";
 	*w << DisplayKeys(Key.MvSongDown) << "Move item(s) down\n";
+	*w << DisplayKeys(Key.Clear) << "Clear current playlist\n";
 	
 	*w << "\n\n   " << fmtBold << "Keys - Lyrics\n -----------------------------------------\n" << fmtBoldEnd;
 	*w << DisplayKeys(Key.Space) << "Switch for following lyrics of now playing song\n";

src/libmpdclient.c

@@ -2026,7 +2026,7 @@ void mpd_sendListPlaylistCommand(mpd_Connection *connection, char *path)
 	free(query);
 }
 
-void mpd_sendPlaylistClearCommand(mpd_Connection *connection, char *path)
+void mpd_sendPlaylistClearCommand(mpd_Connection *connection, const char *path)
 {
 	char *sPath = mpd_sanitizeArg(path);
 	int len = strlen("playlistclear")+2+strlen(sPath)+3;

src/libmpdclient.h

@@ -664,7 +664,7 @@ void mpd_startPlaylistSearch(mpd_Connection *connection, int exact);
 
 void mpd_startStatsSearch(mpd_Connection *connection);
 
-void mpd_sendPlaylistClearCommand(mpd_Connection *connection, char *path);
+void mpd_sendPlaylistClearCommand(mpd_Connection *connection, const char *path);
 
 void mpd_sendPlaylistAddCommand(mpd_Connection *connection,
                                 const char *playlist, const char *path);

src/mpdpp.cpp

@@ -338,6 +338,16 @@ void Connection::ClearPlaylist() const
 	}
 }
 
+void Connection::ClearPlaylist(const string &playlist) const
+{
+	if (isConnected)
+	{
+		mpd_sendPlaylistClearCommand(itsConnection, playlist.c_str());
+		if (!isCommandsListEnabled)
+			mpd_finishCommand(itsConnection);
+	}
+}
+
 void Connection::AddToPlaylist(const string &path, const Song &s) const
 {
 	if (!s.Empty())

src/ncmpcpp.cpp

@@ -1512,8 +1512,18 @@ int main(int argc, char *argv[])
 			}
 			else
 			{
+				if (myScreen == myPlaylistEditor && myPlaylistEditor->Playlists->Empty())
+					continue;
 				ShowMessage("Clearing playlist...");
+				if (myScreen == myPlaylistEditor)
+				{
+					Mpd->ClearPlaylist(locale_to_utf_cpy(myPlaylistEditor->Playlists->Current()));
+					myPlaylistEditor->Content->Clear(0);
+				}
+				else
+				{
 					Mpd->ClearPlaylist();
+				}
 				ShowMessage("Cleared playlist!");
 			}
 		}