[gnome-games] nintendo-ds: Set screen gap for top/bottom screen layout

[Alexander Mikhaylenko <alexm src gnome org>]

commit 6f2a37c443be33eabd2bd10d3c2e196e136867c0
Author: Neville <nevilleantony98 gmail com>
Date:   Thu Feb 27 22:22:12 2020 +0530

    nintendo-ds: Set screen gap for top/bottom screen layout
    
    Fixes #238

 plugins/nintendo-ds/src/nintendo-ds-runner.vala | 71 ++++++++++++++++++++++---
 1 file changed, 64 insertions(+), 7 deletions(-)
---
diff --git a/plugins/nintendo-ds/src/nintendo-ds-runner.vala b/plugins/nintendo-ds/src/nintendo-ds-runner.vala
index 83338e3e..5aea4cb9 100644
--- a/plugins/nintendo-ds/src/nintendo-ds-runner.vala
+++ b/plugins/nintendo-ds/src/nintendo-ds-runner.vala
@@ -3,8 +3,15 @@
 private class Games.NintendoDsRunner : RetroRunner {
        // Map the 1,2,3,4 key values to the 4 screen layouts of the Nintendo DS
        private static HashTable<uint, NintendoDsLayout?> layouts;
+       private static HashTable<string, string> gap_overrides;
 
        private const string SCREENS_LAYOUT_OPTION = "desmume_screens_layout";
+       private const string SCREENS_GAP_OPTION = "desmume_screens_gap";
+       private const string SCREENS_GAP_NONE = "0";
+       private const string SCREENS_GAP_DEFAULT = "80";
+
+       private const size_t HEADER_GAME_CODE_OFFSET = 12;
+       private const size_t HEADER_GAME_CODE_SIZE = 3;
 
        private NintendoDsLayout _screen_layout;
        public NintendoDsLayout screen_layout {
@@ -31,12 +38,55 @@ private class Games.NintendoDsRunner : RetroRunner {
                layouts[Gdk.Key.@2] = NintendoDsLayout.LEFT_RIGHT;
                layouts[Gdk.Key.@3] = NintendoDsLayout.RIGHT_LEFT;
                layouts[Gdk.Key.@4] = NintendoDsLayout.QUICK_SWITCH;
+
+               gap_overrides = new HashTable<string, string> (str_hash, str_equal);
+
+               try {
+                       var bytes = resources_lookup_data 
("/org/gnome/Games/plugins/nintendo-ds/layout-overrides", ResourceLookupFlags.NONE);
+                       var text = (string) bytes.get_data ();
+                       var lines = text.split ("\n");
+
+                       foreach (var line in lines) {
+                               var data = line.split ("#", 2);
+                               if (data.length < 2)
+                                       continue;
+
+                               var fields = data[0].strip ().split (" ", 2);
+                               if (fields.length < 2)
+                                       continue;
+
+                               var key = fields[0];
+                               var value = fields[1];
+                               gap_overrides[key] = value;
+                       }
+               }
+               catch (Error e) {
+                       critical ("Couldn't read layout overrides: %s", e.message);
+               }
        }
 
        private bool core_supports_layouts () {
                var core = get_core ();
 
-               return core != null && core.has_option (SCREENS_LAYOUT_OPTION);
+               return core != null && core.has_option (SCREENS_LAYOUT_OPTION) && core.has_option 
(SCREENS_GAP_OPTION);
+       }
+
+       private string get_screen_gap_width () {
+
+               try {
+                       assert (media_set.get_size () == 1);
+                       var uris = media_set.get_media (0).get_uris ();
+                       var file = uris[0].to_file ();
+                       var stream = new StringInputStream (file);
+                       string game_code = stream.read_string_for_size (HEADER_GAME_CODE_OFFSET, 
HEADER_GAME_CODE_SIZE);
+
+                       return gap_overrides[game_code] ?? SCREENS_GAP_DEFAULT;
+               }
+               catch (Error e) {
+                       critical ("Couldn't read the header: %s", e.message);
+
+                       return SCREENS_GAP_DEFAULT;
+               }
        }
 
        private void update_screen_layout () {
@@ -45,17 +95,24 @@ private class Games.NintendoDsRunner : RetroRunner {
 
                var core = get_core ();
 
-               var option = core.get_option (SCREENS_LAYOUT_OPTION);
-
-               var option_value = screen_layout.get_value ();
+               var screens_layout_option = core.get_option (SCREENS_LAYOUT_OPTION);
+               var screens_layout_option_value = screen_layout.get_value ();
                if (screen_layout == NintendoDsLayout.QUICK_SWITCH)
-                       option_value = view_bottom_screen ? "bottom only" : "top only";
+                       screens_layout_option_value = view_bottom_screen ? "bottom only" : "top only";
+
+               var screens_gap_option = core.get_option (SCREENS_GAP_OPTION);
+               string screens_gap;
+               if (screen_layout == NintendoDsLayout.TOP_BOTTOM)
+                       screens_gap = get_screen_gap_width ();
+               else
+                       screens_gap = SCREENS_GAP_NONE;
 
                try {
-                       option.set_value (option_value);
+                       screens_layout_option.set_value (screens_layout_option_value);
+                       screens_gap_option.set_value (screens_gap);
                }
                catch (Error e) {
-                       critical (e.message);
+                       critical ("Failed to set desmume option: %s", e.message);
                }
        }