[gnome-games/wip/exalm/covers: 4/5] game-thumbnail: Load covers in a separate thread

[Alexander Mikhaylenko <alexm src gnome org>]

commit 9721a98d7f521406186b59b3990fcfd31c473de7
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Sun Nov 17 16:39:49 2019 +0500

    game-thumbnail: Load covers in a separate thread
    
    Use CoverLoader to fetch covers. Throw away the result if the thumbnail
    has been resized while it loaded.

 src/ui/application.vala    |   6 +++
 src/ui/game-thumbnail.vala | 131 ++++++++++++---------------------------------
 2 files changed, 39 insertions(+), 98 deletions(-)
---
diff --git a/src/ui/application.vala b/src/ui/application.vala
index e9106291..802d26b1 100644
--- a/src/ui/application.vala
+++ b/src/ui/application.vala
@@ -12,6 +12,7 @@ public class Games.Application : Gtk.Application {
        private bool game_list_loaded;
 
        private GameCollection game_collection;
+       private CoverLoader cover_loader;
 
        private Manette.Monitor manette_monitor;
 
@@ -208,6 +209,7 @@ public class Games.Application : Gtk.Application {
 
                init_game_sources ();
                load_game_list.begin ();
+               cover_loader = new CoverLoader ();
                ListStore list_store = new ListStore (typeof (Game));
                game_collection.game_added.connect (game => list_store.append (game));
 
@@ -456,6 +458,10 @@ public class Games.Application : Gtk.Application {
                return game_collection;
        }
 
+       internal CoverLoader get_cover_loader () {
+               return cover_loader;
+       }
+
        internal new static Application get_default () {
                return GLib.Application.get_default () as Application;
        }
diff --git a/src/ui/game-thumbnail.vala b/src/ui/game-thumbnail.vala
index 7df97cc8..04fab0ff 100644
--- a/src/ui/game-thumbnail.vala
+++ b/src/ui/game-thumbnail.vala
@@ -25,16 +25,19 @@ private class Games.GameThumbnail : Gtk.DrawingArea {
                        cover = game.get_cover ();
 
                        if (cover != null)
-                               cover_changed_id = cover.changed.connect (invalidate_cover);
+                               cover_changed_id = cover.changed.connect (() => {
+                                       try_load_cover = true;
+                                       queue_draw ();
+                               });
 
-                       invalidate_cover ();
+                       queue_draw ();
                }
        }
 
-       private bool tried_loading_cover;
-       private Gdk.Pixbuf? cover_cache;
-       private int previous_cover_width;
-       private int previous_cover_height;
+       private Gdk.Pixbuf? cover_pixbuf;
+       private bool loading_cover;
+       private bool try_load_cover;
+       private int last_size;
 
        public struct DrawingContext {
                Cairo.Context cr;
@@ -44,6 +47,10 @@ private class Games.GameThumbnail : Gtk.DrawingArea {
                int height;
        }
 
+       construct {
+               try_load_cover = true;
+       }
+
        static construct {
                set_css_name ("gamesgamethumbnail");
        }
@@ -177,107 +184,35 @@ private class Games.GameThumbnail : Gtk.DrawingArea {
        }
 
        private Gdk.Pixbuf? get_scaled_cover (DrawingContext context) {
-               if (previous_cover_width != context.width * scale_factor) {
-                       previous_cover_width = context.width * scale_factor;
-                       cover_cache = null;
-                       tried_loading_cover = false;
-               }
-
-               if (previous_cover_height != context.height * scale_factor) {
-                       previous_cover_height = context.height * scale_factor;
-                       cover_cache = null;
-                       tried_loading_cover = false;
-               }
-
-               if (cover_cache != null)
-                       return cover_cache;
-
                var size = int.min (context.width, context.height) * scale_factor;
 
-               load_cover_cache_from_disk (context, size);
-               if (cover_cache != null)
-                       return cover_cache;
-
-               var g_icon = cover.get_cover ();
-               if (g_icon == null)
-                       return null;
-
-               var theme = Gtk.IconTheme.get_default ();
-               var lookup_flags = Gtk.IconLookupFlags.FORCE_SIZE | Gtk.IconLookupFlags.FORCE_REGULAR;
-               var icon_info = theme.lookup_by_gicon (g_icon, (int) size, lookup_flags);
-
-               try {
-                       cover_cache = icon_info.load_icon ();
-                       save_cover_cache_to_disk (size);
-               }
-               catch (Error e) {
-                       warning (@"Couldn’t load the icon: $(e.message)\n");
+               if (size != last_size) {
+                       cover_pixbuf = null;
+                       try_load_cover = true;
                }
 
-               return cover_cache;
-       }
+               if (!try_load_cover)
+                       return cover_pixbuf;
 
-       private void load_cover_cache_from_disk (DrawingContext context, int size) {
-               if (tried_loading_cover)
-                       return;
+               var loader = Application.get_default ().get_cover_loader ();
 
-               tried_loading_cover = true;
+               last_size = size;
 
-               string cover_cache_path;
-               try {
-                       cover_cache_path = get_cover_cache_path (size);
-               }
-               catch (Error e) {
-                       critical (e.message);
+               try_load_cover = false;
+               loading_cover = true;
+               loader.fetch_cover (game, size, (s, pixbuf) => {
+                       if (s != last_size) {
+                               cover_pixbuf = null;
+                               try_load_cover = true;
+                       } else
+                       if (pixbuf != null)
+                               cover_pixbuf = pixbuf;
 
-                       return;
-               }
-
-               try {
-                       cover_cache = new Gdk.Pixbuf.from_file_at_scale (cover_cache_path,
-                                                                        context.width * scale_factor,
-                                                                        context.height * scale_factor,
-                                                                        true);
-               }
-               catch (Error e) {
-                       debug (e.message);
-               }
-       }
-
-       private void save_cover_cache_to_disk (int size) {
-               if (cover_cache == null)
-                       return;
-
-               Application.try_make_dir (Application.get_covers_cache_dir (size));
-               var now = new GLib.DateTime.now_local ();
-               var creation_time = now.to_string ();
-
-               try {
-                       var cover_cache_path = get_cover_cache_path (size);
-                       cover_cache.save (cover_cache_path, "png",
-                                         "tEXt::Software", "GNOME Games",
-                                         "tEXt::Creation Time", creation_time.to_string (),
-                                         null);
-               }
-               catch (Error e) {
-                       critical (e.message);
-               }
-       }
-
-       private string get_cover_cache_path (int size) throws Error {
-               var dir = Application.get_covers_cache_dir (size);
-
-               assert (uid != null);
-
-               var uid = uid.get_uid ();
-
-               return @"$dir/$uid.png";
-       }
+                       loading_cover = false;
+                       queue_draw ();
+               });
 
-       private void invalidate_cover () {
-               cover_cache = null;
-               tried_loading_cover = false;
-               queue_draw ();
+               return cover_pixbuf;
        }
 
        private void draw_pixbuf (DrawingContext context, Gdk.Pixbuf pixbuf) {