Refactor app launching (#174)

- Refactor the way apps work: Instead of a C interface, they are now C++ classes. The main reasoning is that attaching data to an app was cumbersome. Having different implementations for different kinds of apps was cumbersome too. (3 or 4 layers of manifest nesting for the TactilityC project)
- External apps are still written in C, but they get a createData/destroyData in their manifest, so:
- External apps now have their own manifest.
- All functions in the original AppManifest are removed and replaced by a single `createApp` function
- External apps now automatically register (each app individually!) when they run the first time. As a side-effect they become visible in the `AppList` app!
- Adapted all apps for the new interface.
- Adapted all internal logic for these changes (Gui, ViewPort, Loader, AppContext, AppInstance, etc.)
- Rewrote parts of Loader to use std::shared_ptr to make the code much safer.
- Added a refcount check for the `AppInstance` and `App` at the end of their lifecycle. Show warning if refcount is too high.

Tactility/Source/app/applist/AppList.cpp

@@ -8,54 +8,61 @@
 
 namespace tt::app::applist {
 
-static void onAppPressed(lv_event_t* e) {
-    const auto* manifest = static_cast<const AppManifest*>(lv_event_get_user_data(e));
-    service::loader::startApp(manifest->id);
-}
 
-static void createAppWidget(const AppManifest* manifest, void* parent) {
-    tt_check(parent);
-    auto* list = reinterpret_cast<lv_obj_t*>(parent);
-    const void* icon = !manifest->icon.empty() ? manifest->icon.c_str() : TT_ASSETS_APP_ICON_FALLBACK;
-    lv_obj_t* btn = lv_list_add_button(list, icon, manifest->name.c_str());
-    lv_obj_add_event_cb(btn, &onAppPressed, LV_EVENT_SHORT_CLICKED, (void*)manifest);
-}
+class AppListApp : public App {
 
-static void onShow(TT_UNUSED AppContext& app, lv_obj_t* parent) {
-    auto* toolbar = lvgl::toolbar_create(parent, app);
-    lv_obj_align(toolbar, LV_ALIGN_TOP_MID, 0, 0);
+private:
 
-    lv_obj_t* list = lv_list_create(parent);
-    lv_obj_set_width(list, LV_PCT(100));
-    lv_obj_align_to(list, toolbar, LV_ALIGN_OUT_BOTTOM_MID, 0, 0);
-
-    auto toolbar_height = lv_obj_get_height(toolbar);
-    auto parent_content_height = lv_obj_get_content_height(parent);
-    lv_obj_set_height(list, parent_content_height - toolbar_height);
-
-    auto manifests = getApps();
-    std::sort(manifests.begin(), manifests.end(), SortAppManifestByName);
-
-    lv_list_add_text(list, "User");
-    for (const auto& manifest: manifests) {
-        if (manifest->type == TypeUser) {
-            createAppWidget(manifest, list);
-        }
+    static void onAppPressed(lv_event_t* e) {
+        const auto* manifest = static_cast<const AppManifest*>(lv_event_get_user_data(e));
+        service::loader::startApp(manifest->id);
     }
 
-    lv_list_add_text(list, "System");
-    for (const auto& manifest: manifests) {
-        if (manifest->type == TypeSystem) {
-            createAppWidget(manifest, list);
+    static void createAppWidget(const std::shared_ptr<AppManifest>& manifest, lv_obj_t* list) {
+        const void* icon = !manifest->icon.empty() ? manifest->icon.c_str() : TT_ASSETS_APP_ICON_FALLBACK;
+        lv_obj_t* btn = lv_list_add_button(list, icon, manifest->name.c_str());
+        lv_obj_add_event_cb(btn, &onAppPressed, LV_EVENT_SHORT_CLICKED, (void*)manifest.get());
+    }
+
+public:
+
+    void onShow(TT_UNUSED AppContext& app, lv_obj_t* parent) override {
+        auto* toolbar = lvgl::toolbar_create(parent, app);
+        lv_obj_align(toolbar, LV_ALIGN_TOP_MID, 0, 0);
+
+        lv_obj_t* list = lv_list_create(parent);
+        lv_obj_set_width(list, LV_PCT(100));
+        lv_obj_align_to(list, toolbar, LV_ALIGN_OUT_BOTTOM_MID, 0, 0);
+
+        auto toolbar_height = lv_obj_get_height(toolbar);
+        auto parent_content_height = lv_obj_get_content_height(parent);
+        lv_obj_set_height(list, parent_content_height - toolbar_height);
+
+        auto manifests = getApps();
+        std::sort(manifests.begin(), manifests.end(), SortAppManifestByName);
+
+        lv_list_add_text(list, "User");
+        for (const auto& manifest: manifests) {
+            if (manifest->type == Type::User) {
+                createAppWidget(manifest, list);
+            }
+        }
+
+        lv_list_add_text(list, "System");
+        for (const auto& manifest: manifests) {
+            if (manifest->type == Type::System) {
+                createAppWidget(manifest, list);
+            }
         }
     }
-}
+};
+
 
 extern const AppManifest manifest = {
     .id = "AppList",
     .name = "Apps",
-    .type = TypeHidden,
-    .onShow = onShow,
+    .type = Type::Hidden,
+    .createApp = create<AppListApp>,
 };
 
 } // namespace