Wrap filesystem iterator

Change to wrapping the filesystem iterator rather than iterating over
table values. Also centralise the is_playlist check and hide Playlists
menu if none are present

lua/file_browser.lua

@@ -8,11 +8,11 @@ local backstack = require("backstack")
 local font = require("font")
 local queue = require("queue")
 local playing = require("playing")
-local styles = require("styles")
 local playback = require("playback")
 local theme = require("theme")
 local screen = require("screen")
 local filesystem = require("filesystem")
+local playlist_iterator = require("playlist_iterator")
 
 return screen:new {
   create_ui = function(self)
@@ -70,8 +70,7 @@ return screen:new {
               breadcrumb = item:filepath()
             })
           elseif
-              item:filepath():match("%.playlist$") or
-              item:filepath():match("%.m3u8?$") then
+              playlist_iterator:is_playlist(item) then
             queue.open_playlist(item:filepath())
             playback.playing:set(true)
             backstack.push(playing:new())

lua/main_menu.lua

@@ -11,7 +11,6 @@ local browser = require("browser")
 local playing = require("playing")
 local styles = require("styles")
 local filesystem = require("filesystem")
-local screen = require("screen")
 local font = require("font")
 local theme = require("theme")
 local img = require("images")
@@ -151,6 +150,14 @@ return widgets.MenuScreen:new {
       indexes_list:clear_flag(lvgl.FLAG.HIDDEN)
     end
 
+    local function hide_playlist_listing()
+      playlist_btn:add_flag(lvgl.FLAG.HIDDEN)
+    end
+
+    local function show_playlist_listing()
+      playlist_btn:clear_flag(lvgl.FLAG.HIDDEN)
+    end
+
     local function update_visible_indexes()
       local has_valid_index = false
       for _, idx in ipairs(indexes) do
@@ -164,6 +171,13 @@ return widgets.MenuScreen:new {
       end
       if has_valid_index then
         hide_no_indexes()
+
+        -- If we have valid indexes, then also check for playlists
+        if filesystem.iterator("/Playlists/"):next() == nil then
+          hide_playlist_listing()
+        else
+          show_playlist_listing()
+        end
       else
         if require("database").updating:get() then
           show_no_indexes("The database is updating for the first time. Please wait.")

lua/playlist_browser.lua

@@ -12,7 +12,7 @@ local font = require("font")
 local theme = require("theme")
 local playback = require("playback")
 local queue = require("queue")
-local table_iterator = require("table_iterator")
+local playlist_iterator = require("playlist_iterator")
 local img = require("images")
 
 
@@ -60,11 +60,6 @@ return screen:new {
       }
     end
 
-    local is_playlist = function(item)
-      return item:filepath():match("%.playlist$")
-          or item:filepath():match("%.m3u8?$")
-    end
-
     local get_icon_func = function(item)
       if item:is_directory() then
         return img.files
@@ -73,16 +68,7 @@ return screen:new {
       end
     end
 
-    local playlists_and_dirs = {};
-    for item in self.iterator do
-      if
-          is_playlist(item) or
-          item:is_directory() then
-        table.insert(playlists_and_dirs, item)
-      end
-    end
-
-    widgets.InfiniteList(self.root, table_iterator:create(playlists_and_dirs), {
+    widgets.InfiniteList(self.root, playlist_iterator:create(self.iterator), {
       focus_first_item = true,
       get_icon = get_icon_func,
       callback = function(item)
@@ -95,7 +81,7 @@ return screen:new {
                 breadcrumb = item:filepath()
               })
           elseif
-              is_playlist(item) then
+              playlist_iterator:is_playlist(item) then
             -- TODO: playlist viewer
             queue.open_playlist(item:filepath())
             playback.playing:set(true)

lua/playlist_iterator.lua

@@ -0,0 +1,35 @@
+local PlaylistIterator = {}
+
+function PlaylistIterator:is_playlist(item)
+  return item:filepath():match("%.playlist$")
+      or item:filepath():match("%.m3u8?$")
+end
+
+function PlaylistIterator:create(fs_iterator)
+  local iterator = fs_iterator:clone()
+  local obj = {};
+
+  local find_matching = function(iterate_fn)
+    local next = iterate_fn(iterator);
+    while next and (not PlaylistIterator:is_playlist(next) and not next:is_directory()) do
+      next = iterate_fn();
+    end
+    return next;
+  end
+
+  function obj:clone()
+    return PlaylistIterator:create(iterator)
+  end
+
+  function obj:next()
+    return find_matching(iterator.next)
+  end
+
+  function obj:prev()
+    return find_matching(iterator.prev)
+  end
+
+  return obj
+end
+
+return PlaylistIterator

lua/table_iterator.lua

@@ -1,27 +0,0 @@
-
-local TableIterator = {}
-
-function TableIterator:create(table)
-  local iterator = {};
-  iterator.index = 0;
-  iterator.table = table;
-
-  function iterator:clone()
-    return TableIterator:create(table)
-  end
-  
-  function iterator:next()
-    self.index = self.index + 1
-    return self.table[self.index]
-  end  
-  
-  function iterator:prev()
-    self.index = self.index - 1
-    return self.table[self.index]
-  end
-
-  return iterator
-end
-
-
-return TableIterator