[gnome-games/wip/exalm/platform-preferences: 50/65] retro: Add RetroCoreManager

[Alexander Mikhaylenko <alexm src gnome org>]

commit 5748f5222f6589b7ed90fbaeb1db368aa0a8bd68
Author: Alexander Mikhaylenko <exalm7659 gmail com>
Date:   Thu Sep 27 21:59:15 2018 +0500

    retro: Add RetroCoreManager
    
    Searching cores can take some time, so make it a singleton.

 src/meson.build                   |  1 +
 src/retro/retro-core-manager.vala | 76 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+)
---
diff --git a/src/meson.build b/src/meson.build
index 7366e14e..b9ab1f29 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -109,6 +109,7 @@ vala_sources = [
   'keyboard/keyboard-mapping-builder.vala',
   'keyboard/keyboard-mapping-manager.vala',
 
+  'retro/retro-core-manager.vala',
   'retro/retro-core-source.vala',
   'retro/retro-error.vala',
   'retro/retro-gamepad.vala',
diff --git a/src/retro/retro-core-manager.vala b/src/retro/retro-core-manager.vala
new file mode 100644
index 00000000..07c21ba1
--- /dev/null
+++ b/src/retro/retro-core-manager.vala
@@ -0,0 +1,76 @@
+// This file is part of GNOME Games. License: GPL-3.0+.
+
+public class Games.RetroCoreManager : Object {
+       private static RetroCoreManager instance;
+
+       private Retro.CoreDescriptor[] core_descriptors;
+       private bool searched;
+
+       public static RetroCoreManager get_instance () {
+               if (instance == null)
+                       instance = new RetroCoreManager ();
+
+               return instance;
+       }
+
+       private RetroCoreManager () {
+               searched = false;
+               core_descriptors = {};
+       }
+
+       private void search_modules () {
+               var modules = new Retro.ModuleQuery (true);
+               foreach (var core_descriptor in modules) {
+                       try {
+                               if (!core_descriptor.get_is_emulator ())
+                                       continue;
+
+                               if (core_descriptor.get_module_file () == null)
+                                       continue;
+
+                               core_descriptors += core_descriptor;
+                       }
+                       catch (Error e) {
+                               debug (e.message);
+                       }
+               }
+       }
+
+       public Retro.CoreDescriptor[] get_cores_for_platform (RetroPlatform platform) {
+               if (!searched) {
+                       searched = true;
+                       search_modules ();
+               }
+
+               var result = new Array<Retro.CoreDescriptor> ();
+
+               var path = "/org/gnome/Games/platforms/%s/".printf (platform.get_id ());
+               var settings = new Settings.with_path ("org.gnome.Games.platforms", path);
+
+               var preferred_core = settings.get_string ("preferred-core");
+
+               foreach (var core_descriptor in core_descriptors) {
+                       try {
+                               var platform_id = platform.get_id ();
+                               var mime_types = platform.get_mime_types ();
+
+                               if (!core_descriptor.has_platform (platform_id))
+                                       continue;
+
+                               if (!core_descriptor.get_platform_supports_mime_types (platform_id, 
mime_types))
+                                       continue;
+
+                               // Insert preferred core at the start of the list
+                               if (core_descriptor.get_id () == preferred_core)
+                                       result.prepend_val (core_descriptor);
+                               else
+                                       result.append_val (core_descriptor);
+                       }
+                       catch (Error e) {
+                               debug (e.message);
+                       }
+               }
+
+               return result.data;
+       }
+}