apps: Add "keep current track when replacing playlist" setting

Add a setting that makes Play and Play Shuffled in the playlist
context menu leave the current song (if any) playing when they
replace the playlist. Default to on, since this was the behavior
of the old "Clear List & Play Next" option.

Change-Id: I1340aed5c28bb3244e36d0953b3308ae59681c97

apps/lang/english.lang

@@ -16354,3 +16354,17 @@
     *: "Play Shuffled"
   </voice>
 </phrase>
+<phrase>
+  id: LANG_KEEP_CURRENT_TRACK_ON_REPLACE
+  desc: used in the playlist settings menu
+  user: core
+  <source>
+    *: "Keep Current Track When Replacing Playlist"
+  </source>
+  <dest>
+    *: "Keep Current Track When Replacing Playlist"
+  </dest>
+  <voice>
+    *: "Keep Current Track When Replacing Playlist"
+  </voice>
+</phrase>

apps/menus/playlist_menu.c

@@ -169,12 +169,17 @@ MAKE_MENU(viewer_settings_menu, ID2P(LANG_PLAYLISTVIEWER_SETTINGS),
 
 /* Current Playlist submenu */
 MENUITEM_SETTING(warn_on_erase, &global_settings.warnon_erase_dynplaylist, NULL);
+MENUITEM_SETTING(keep_current_track_on_replace, &global_settings.keep_current_track_on_replace_playlist, NULL);
 MENUITEM_SETTING(show_shuffled_adding_options, &global_settings.show_shuffled_adding_options, NULL);
 MENUITEM_SETTING(show_queue_options, &global_settings.show_queue_options, NULL);
 MENUITEM_SETTING(playlist_reload_after_save, &global_settings.playlist_reload_after_save, NULL);
 MAKE_MENU(currentplaylist_settings_menu, ID2P(LANG_CURRENT_PLAYLIST),
           NULL, Icon_Playlist,
-          &warn_on_erase, &show_shuffled_adding_options, &show_queue_options, &playlist_reload_after_save);
+          &warn_on_erase,
+          &keep_current_track_on_replace,
+          &show_shuffled_adding_options,
+          &show_queue_options,
+          &playlist_reload_after_save);
 
 MAKE_MENU(playlist_settings, ID2P(LANG_PLAYLISTS), NULL,
           Icon_Playlist,

apps/onplay.c

@@ -504,8 +504,8 @@ static int add_to_playlist(void* arg)
 {
     struct add_to_pl_param* param = arg;
     int position = param->position;
-    bool new_playlist = param->replace ? true : false;
+    bool new_playlist = !!param->replace;
-    bool queue = param->queue ? true : false;
+    bool queue = !!param->queue;
 
     /* warn if replacing the playlist */
     if (new_playlist && !warn_on_pl_erase())
@@ -519,6 +519,15 @@ static int add_to_playlist(void* arg)
 
     splash(0, ID2P(LANG_WAIT));
 
+    if (new_playlist && global_settings.keep_current_track_on_replace_playlist)
+    {
+        if (audio_status() & AUDIO_STATUS_PLAY)
+        {
+            playlist_remove_all_tracks(NULL);
+            new_playlist = false;
+        }
+    }
+
     if (new_playlist)
         playlist_create(NULL, NULL);
 

apps/settings.h

@@ -607,6 +607,7 @@ struct user_settings
     bool fade_on_stop; /* fade on pause/unpause/stop */
     bool playlist_shuffle;
     bool warnon_erase_dynplaylist; /* warn when erasing dynamic playlist */
+    bool keep_current_track_on_replace_playlist;
     bool show_shuffled_adding_options; /* whether to display options for adding shuffled tracks to dynamic playlist */
     int show_queue_options; /* how and whether to display options to queue tracks */
 #ifdef HAVE_ALBUMART

apps/settings_list.c

@@ -1753,9 +1753,11 @@ const struct settings_list settings[] = {
                    ID2P(LANG_CODEPAGE_JAPANESE),
                    ID2P(LANG_CODEPAGE_SIMPLIFIED), ID2P(LANG_CODEPAGE_KOREAN),
                    ID2P(LANG_CODEPAGE_TRADITIONAL), ID2P(LANG_CODEPAGE_UTF8)),
+
     OFFON_SETTING(0, warnon_erase_dynplaylist, LANG_WARN_ERASEDYNPLAYLIST_MENU,
                   true, "warn when erasing dynamic playlist",NULL),
-
+    OFFON_SETTING(0, keep_current_track_on_replace_playlist, LANG_KEEP_CURRENT_TRACK_ON_REPLACE,
+                  true, "keep current track when replacing playlist",NULL),
     OFFON_SETTING(0, show_shuffled_adding_options, LANG_SHOW_SHUFFLED_ADDING_OPTIONS, true,
                       "show shuffled adding options", NULL),
     CHOICE_SETTING(0, show_queue_options, LANG_SHOW_QUEUE_OPTIONS, 1,

manual/configure_rockbox/playlist_options.tex

@@ -31,6 +31,12 @@ related to playlists.
   If set to \setting{Yes}, Rockbox will provide a warning if the user attempts to
   take an action that will cause Rockbox to erase the current dynamic playlist.
 
+  \item[Keep Current Track When Replacing Playlist.]
+  If set to \setting{Yes}, then \setting{Play} and \setting{Play Shuffled} in
+  the \setting{Current Playlist submenu} will allow the current track to finish
+  playing before the new tracks play. If set to \setting{No}, the current
+  track will be interrupted and new tracks will start playing immediately.
+
   \item[Show Shuffled Adding Options.]
   If set to \setting{No}, Rockbox will not offer to add shuffled tracks
   in the \setting{Current Playlist submenu}.

manual/working_with_playlists/main.tex

@@ -118,7 +118,10 @@ following two options will achieve that effect.
 
 \begin{description}
 \item [Play.] Replace all entries in the dynamic playlist with the selected
-  tracks and start playing the new playlist immediately.
+  tracks. If \setting{Keep Current Track When Replacing Playlist} is set to
+  \setting{Yes}, the new tracks will play after the current track finishes
+  playing; if no track is playing or the setting is \setting{No}, the new
+  tracks will begin playing immediately.
 
 \item [Play Shuffled.] Similar, except the tracks will be added to the new
   playlist in random order.