[gnome-software/wip/hughsie/cachekey: 4/4] Allow GsApp objects to implement a custom cache key

[Richard Hughes <rhughes src gnome org>]

commit 9ff905cd53a94774c8b13c214b3aa6cd348f0b68
Author: Richard Hughes <richard hughsie com>
Date:   Thu Jun 20 11:31:46 2019 +0100

    Allow GsApp objects to implement a custom cache key
    
    This allows us to maintain a plugin cache when the unique ID is not unique
    enough to disambiguate the objects. For instance, flatpak applications created
    from an AppStream search result do not have a "branch" set.
    
    Fixes https://gitlab.gnome.org/GNOME/gnome-software/issues/684

 lib/gs-app.c                     | 21 +++++++++++++++++++++
 lib/gs-app.h                     |  4 +++-
 plugins/core/gs-appstream.c      |  2 +-
 plugins/flatpak/gs-flatpak-app.c |  8 ++++++++
 4 files changed, 33 insertions(+), 2 deletions(-)
---
diff --git a/lib/gs-app.c b/lib/gs-app.c
index 186ceb54..7fefc7b4 100644
--- a/lib/gs-app.c
+++ b/lib/gs-app.c
@@ -1260,6 +1260,27 @@ gs_app_get_unique_id (GsApp *app)
        return gs_app_get_unique_id_unlocked (app);
 }
 
+/**
+ * gs_app_get_cache_key:
+ * @app: a #GsApp
+ *
+ * Gets the cache key used for de-duplication.
+ * If the plugin has not provided a custom #GsApp subclass with the `get_cache_key`
+ * vfunc implemented then gs_app_get_unique_id() will be used.
+ *
+ * Returns: A string ID suitable for deduplication
+ *
+ * Since: 3.34
+ **/
+const gchar *
+gs_app_get_cache_key (GsApp *app)
+{
+       GsAppClass *klass = GS_APP_GET_CLASS (app);
+       if (klass->get_cache_key != NULL)
+               return klass->get_cache_key (app);
+       return gs_app_get_unique_id (app);
+}
+
 /**
  * gs_app_set_unique_id:
  * @app: a #GsApp
diff --git a/lib/gs-app.h b/lib/gs-app.h
index cd185154..35240081 100644
--- a/lib/gs-app.h
+++ b/lib/gs-app.h
@@ -26,7 +26,8 @@ struct _GsAppClass
        GObjectClass             parent_class;
        void                     (*to_string)   (GsApp          *app,
                                                 GString        *str);
-       gpointer                 padding[30];
+       const gchar             *(*get_cache_key) (GsApp        *app);
+       gpointer                 padding[29];
 };
 
 /**
@@ -191,6 +192,7 @@ gboolean    gs_app_get_allow_cancel         (GsApp  *app);
 void           gs_app_set_allow_cancel          (GsApp *app,
                                                  gboolean      allow_cancel);
 const gchar    *gs_app_get_unique_id           (GsApp          *app);
+const gchar    *gs_app_get_cache_key           (GsApp          *app);
 const gchar    *gs_app_get_branch              (GsApp          *app);
 void            gs_app_set_branch              (GsApp          *app,
                                                 const gchar    *branch);
diff --git a/plugins/core/gs-appstream.c b/plugins/core/gs-appstream.c
index edab1271..f680f656 100644
--- a/plugins/core/gs-appstream.c
+++ b/plugins/core/gs-appstream.c
@@ -27,7 +27,7 @@ gs_appstream_create_app (GsPlugin *plugin, XbSilo *silo, XbNode *component, GErr
                return NULL;
 
        /* look for existing object */
-       app = gs_plugin_cache_lookup (plugin, gs_app_get_unique_id (app_new));
+       app = gs_plugin_cache_lookup (plugin, gs_app_get_cache_key (app_new));
        if (app != NULL)
                return app;
 
diff --git a/plugins/flatpak/gs-flatpak-app.c b/plugins/flatpak/gs-flatpak-app.c
index 0f587877..50885557 100644
--- a/plugins/flatpak/gs-flatpak-app.c
+++ b/plugins/flatpak/gs-flatpak-app.c
@@ -51,6 +51,13 @@ gs_flatpak_app_file_kind_to_string (GsFlatpakAppFileKind file_kind)
        return NULL;
 }
 
+static const gchar *
+gs_flatpak_app_get_cache_key (GsApp *app)
+{
+       /* created by AppStream to be 'runtime/org.test.Runtime/x86_64/master' */
+       return gs_app_get_source_default (app);
+}
+
 static void
 gs_flatpak_app_to_string (GsApp *app, GString *str)
 {
@@ -296,6 +303,7 @@ gs_flatpak_app_class_init (GsFlatpakAppClass *klass)
        GObjectClass *object_class = G_OBJECT_CLASS (klass);
        GsAppClass *klass_app = GS_APP_CLASS (klass);
        klass_app->to_string = gs_flatpak_app_to_string;
+       klass_app->get_cache_key = gs_flatpak_app_get_cache_key;
        object_class->finalize = gs_flatpak_app_finalize;
 }