Reworks to the shuffle system to improve performance and allow fast shuffling from a big library (but this work for all database views)

This improvement brings a huge performance improvement to start a random mix of your library. Previously, the only way to do this was to increase the size of a playlist with absurd sizes number. Now it will respect the limitation but will insert random songs from the current view.

Database: Add true random songs in playlist if it is gonna exceed its maximum capacity

More context is available here : https://www.reddit.com/r/rockbox/comments/1ez0mq4/i_developped_true_full_library_shuffle_for/

Also :
- Improved layout in the DB browser
- New default max playlists capacity is now 2000 on old PortalPlayer targets to give a better user experience and not having to wait dozens of seconds while creating a playlist
- "Show insert shuffled" option is now true by default
- Add a new shortcut to play all songs shuffled in the DB browser
- Now the feature is fully optional and enabled only on targets that have more than 2MB of RAM
- Add entries about this feature in the manual to explain it to the users
Change-Id: I1aebaf7ebcff2bf907080f1861027d530619097c

Change-Id: I3354923b148eeef1975171990e814a1a505d1df0

1 files changed, 19 insertions, 8 deletions

diff --git a/apps/tree.c b/apps/tree.c
index 71a7ee3f62..b4cd9d77b0 100644
--- a/apps/tree.c
+++ b/apps/tree.c
@@ -735,6 +735,17 @@ static int dirbrowse(void)
         oldbutton = button;
         gui_synclist_do_button(&tree_lists, &button);
         tc.selected_item = gui_synclist_get_sel_pos(&tree_lists);
+        int customaction = ONPLAY_NO_CUSTOMACTION;
+        bool do_restore_display = true;
+        #ifdef HAVE_TAGCACHE
+            if (id3db && (button == ACTION_STD_OK || button == ACTION_STD_CONTEXT)) {
+                customaction = tagtree_get_custom_action(&tc);
+                if (customaction == ONPLAY_CUSTOMACTION_SHUFFLE_SONGS) {
+                    button = ACTION_STD_CONTEXT; /** The code to insert shuffled is on the context branch of the switch so we always go here */
+                    do_restore_display = false;
+                }
+            }
+        #endif
         switch ( button ) {
             case ACTION_STD_OK:
                 /* nothing to do if no files to display */
@@ -773,7 +784,7 @@ static int dirbrowse(void)
                     default:
                         break;
                 }
-                restore = true;
+                restore = do_restore_display;
                 break;
 
             case ACTION_STD_CANCEL:
@@ -798,12 +809,12 @@ static int dirbrowse(void)
                     if (ft_exit(&tc) == 3)
                         exit_func = true;
 
-                restore = true;
+                restore = do_restore_display;
                 break;
 
             case ACTION_TREE_STOP:
                 if (list_stop_handler())
-                    restore = true;
+                    restore = do_restore_display;
                 break;
 
             case ACTION_STD_MENU:
@@ -851,7 +862,7 @@ static int dirbrowse(void)
                         skin_update(CUSTOM_STATUSBAR, i, SKIN_REFRESH_ALL);
                 }
 
-                restore = true;
+                restore = do_restore_display;
                 break;
             }
 #endif
@@ -872,7 +883,7 @@ static int dirbrowse(void)
                     break;
 
                 if(!numentries)
-                    onplay_result = onplay(NULL, 0, curr_context, hotkey);
+                    onplay_result = onplay(NULL, 0, curr_context, hotkey, customaction);
                 else {
 #ifdef HAVE_TAGCACHE
                     if (id3db)
@@ -902,7 +913,7 @@ static int dirbrowse(void)
                         ft_assemble_path(buf, sizeof(buf), currdir, entry->name);
 
                     }
-                    onplay_result = onplay(buf, attr, curr_context, hotkey);
+                    onplay_result = onplay(buf, attr, curr_context, hotkey, customaction);
                 }
                 switch (onplay_result)
                 {
@@ -911,7 +922,7 @@ static int dirbrowse(void)
                         break;
 
                     case ONPLAY_OK:
-                        restore = true;
+                        restore = do_restore_display;
                         break;
 
                     case ONPLAY_RELOAD_DIR:
@@ -988,7 +999,7 @@ static int dirbrowse(void)
 
             lastfilter = *tc.dirfilter;
             lastsortcase = global_settings.sort_case;
-            restore = true;
+            restore = do_restore_display;
         }
 
         if (exit_func)