Free graphics resources without item tree traversal

api/sixtyfps-cpp/include/sixtyfps.h

@@ -96,11 +96,9 @@ public:
         sixtyfps_component_window_set_scale_factor(&inner, value);
     }
 
-    template<typename Component>
-    void free_graphics_resources(Component *c) const
+    void free_graphics_resources(const sixtyfps::Slice<ItemRef> &items) const
     {
-        cbindgen_private::sixtyfps_component_window_free_graphics_resources(
-                &inner, vtable::VRef<ComponentVTable> { &Component::component_type, c });
+        cbindgen_private::sixtyfps_component_window_free_graphics_resources(&inner, &items);
     }
 
     void set_focus_item(vtable::VRef<ComponentVTable> c, vtable::VRef<ItemVTable> item)

sixtyfps_compiler/generator/cpp.rs

@@ -894,6 +894,7 @@ fn generate_component(
     let mut repeated_input_branch = vec![];
     let mut repeater_layout_code = vec![];
     let mut tree_array = vec![];
+    let mut item_names_and_vt_symbols = vec![];
     let mut repeater_count = 0;
     super::build_array_helper(component, |item_rc, children_offset, is_flickable_rect| {
         let item = item_rc.borrow();
@@ -944,6 +945,8 @@ fn generate_component(
                 children_offset,
             ));
             handle_item(item_rc, &mut component_struct, &mut init);
+            item_names_and_vt_symbols
+                .push((item.id.clone(), item.base_type.as_native().vtable_symbol.clone()));
         }
     });
 
@@ -979,7 +982,15 @@ fn generate_component(
         if component.parent_element.upgrade().is_some() {
             destructor.push("if (!parent) return;".to_owned())
         }
-        destructor.push("self->window.free_graphics_resources(this);".into());
+        if !item_names_and_vt_symbols.is_empty() {
+            destructor.push("sixtyfps::private_api::ItemRef items[] = {".into());
+            destructor.push(item_names_and_vt_symbols.iter()
+                .map(|(item_name, vt_symbol)|
+                    format!("{{ &sixtyfps::private_api::{vt}, const_cast<decltype(this->{id})*>(&this->{id}) }}", id = item_name, vt = vt_symbol)
+                ).join(","));
+            destructor.push("};".into());
+            destructor.push("window.free_graphics_resources(sixtyfps::Slice<sixtyfps::private_api::ItemRef>{items, std::size(items)});".into());
+        }
 
         component_struct.members.push((
             Access::Public,

sixtyfps_compiler/generator/rust.rs

@@ -611,7 +611,10 @@ fn generate_component(
             Some(quote!(impl sixtyfps::re_exports::PinnedDrop for #component_id {
                 fn drop(self: core::pin::Pin<&mut #component_id>) {
                     use sixtyfps::re_exports::*;
-                    self.window.free_graphics_resources(VRef::new_pin(self.as_ref()));
+                    let items = [
+                        #(VRef::new_pin(Self::FIELD_OFFSETS.#item_names.apply_pin(self.as_ref())),)*
+                    ];
+                    self.window.free_graphics_resources(&Slice::from_slice(&items));
                 }
             })),
             quote!(#[pin_drop]),

sixtyfps_runtime/corelib/eventloop.rs

@@ -13,7 +13,11 @@ LICENSE END */
     [GenericWindow] trait used by the generated code and the run-time to change
     aspects of windows on the screen.
 */
-use crate::component::{ComponentRc, ComponentVTable};
+use crate::{
+    component::{ComponentRc, ComponentVTable},
+    items::ItemRef,
+    slice::Slice,
+};
 use std::cell::RefCell;
 use std::{
     convert::TryInto,
@@ -91,10 +95,7 @@ pub trait GenericWindow {
 
     /// This function is called by the generated code when a component and therefore its tree of items are destroyed. The
     /// implementation typically uses this to free the underlying graphics resources cached via [`crate::graphics::RenderingCache`].
-    fn free_graphics_resources(
-        self: Rc<Self>,
-        component: core::pin::Pin<crate::component::ComponentRef>,
-    );
+    fn free_graphics_resources<'a>(self: Rc<Self>, items: &Slice<'a, Pin<ItemRef<'a>>>);
     /// Installs a binding on the specified property that's toggled whenever the text cursor is supposed to be visible or not.
     fn set_cursor_blink_binding(&self, prop: &crate::properties::Property<bool>);
 
@@ -151,11 +152,8 @@ impl ComponentWindow {
 
     /// This function is called by the generated code when a component and therefore its tree of items are destroyed. The
     /// implementation typically uses this to free the underlying graphics resources cached via [RenderingCache][`crate::graphics::RenderingCache`].
-    pub fn free_graphics_resources(
-        &self,
-        component: core::pin::Pin<crate::component::ComponentRef>,
-    ) {
-        self.0.clone().free_graphics_resources(component);
+    pub fn free_graphics_resources<'a>(&self, items: &Slice<'a, Pin<ItemRef<'a>>>) {
+        self.0.clone().free_graphics_resources(items);
     }
 
     /// Installs a binding on the specified property that's toggled whenever the text cursor is supposed to be visible or not.
@@ -599,12 +597,12 @@ pub mod ffi {
 
     /// Sets the window scale factor, merely for testing purposes.
     #[no_mangle]
-    pub unsafe extern "C" fn sixtyfps_component_window_free_graphics_resources(
+    pub unsafe extern "C" fn sixtyfps_component_window_free_graphics_resources<'a>(
         handle: *const ComponentWindowOpaque,
-        component: Pin<VRef<ComponentVTable>>,
+        items: &Slice<'a, Pin<ItemRef<'a>>>,
     ) {
         let window = &*(handle as *const ComponentWindow);
-        window.free_graphics_resources(component)
+        window.free_graphics_resources(items)
     }
 
     /// Sets the focus item.

sixtyfps_runtime/corelib/graphics.rs

@@ -20,7 +20,6 @@ LICENSE END */
     created by the backend in a type-erased manner.
 */
 extern crate alloc;
-use crate::component::{ComponentRc, ComponentWeak};
 use crate::input::{KeyEvent, KeyboardModifiers, MouseEvent, MouseEventType};
 use crate::items::ItemRef;
 use crate::properties::{InterpolatedPropertyValue, Property, PropertyTracker};
@@ -29,6 +28,10 @@ use crate::rtti::{BuiltinItem, FieldInfo, PropertyInfo, ValueType};
 use crate::SharedArray;
 #[cfg(feature = "rtti")]
 use crate::Signal;
+use crate::{
+    component::{ComponentRc, ComponentWeak},
+    slice::Slice,
+};
 
 use auto_enums::auto_enum;
 use cgmath::Matrix4;
@@ -820,14 +823,11 @@ impl<Backend: GraphicsBackend> crate::eventloop::GenericWindow for GraphicsWindo
         )
     }
 
-    fn free_graphics_resources(
-        self: Rc<Self>,
-        component: core::pin::Pin<crate::component::ComponentRef>,
-    ) {
+    fn free_graphics_resources<'a>(self: Rc<Self>, items: &Slice<'a, Pin<ItemRef<'a>>>) {
         match &*self.map_state.borrow() {
             GraphicsWindowBackendState::Unmapped => {}
             GraphicsWindowBackendState::Mapped(window) => {
-                crate::item_rendering::free_item_rendering_data(component, &window.rendering_cache)
+                crate::item_rendering::free_item_rendering_data(items, &window.rendering_cache)
             }
         }
     }

sixtyfps_runtime/corelib/item_rendering.rs

@@ -14,8 +14,8 @@ use super::graphics::{
     Frame, GraphicsBackend, GraphicsWindow, RenderingCache, RenderingPrimitivesBuilder,
 };
 use super::items::ItemRef;
-use crate::eventloop::ComponentWindow;
 use crate::item_tree::ItemVisitorResult;
+use crate::{eventloop::ComponentWindow, slice::Slice};
 use cgmath::{Matrix4, SquareMatrix, Vector3};
 use std::cell::{Cell, RefCell};
 
@@ -123,18 +123,12 @@ pub(crate) fn render_component_items<Backend: GraphicsBackend>(
     );
 }
 
-pub(crate) fn free_item_rendering_data<Backend: GraphicsBackend>(
-    component: crate::component::ComponentRefPin,
+pub(crate) fn free_item_rendering_data<'a, Backend: GraphicsBackend>(
+    items: &Slice<'a, core::pin::Pin<ItemRef<'a>>>,
     rendering_cache: &RefCell<RenderingCache<Backend>>,
 ) {
-    crate::item_tree::visit_items(
-        component,
-        crate::item_tree::TraversalOrder::FrontToBack,
-        |_, item, _| {
+    for item in items.iter() {
         let cached_rendering_data = item.cached_rendering_data_offset();
         cached_rendering_data.release(rendering_cache);
-            ItemVisitorResult::Continue(())
-        },
-        (),
-    );
+    }
 }

sixtyfps_runtime/interpreter/dynamic_component.rs

@@ -77,9 +77,19 @@ impl<'id> ComponentBox<'id> {
 
 impl<'id> Drop for ComponentBox<'id> {
     fn drop(&mut self) {
-        match eval::window_ref(self.borrow_instance()) {
+        let instance_ref = self.borrow_instance();
+        match eval::window_ref(instance_ref) {
             Some(window) => {
-                window.free_graphics_resources(self.borrow());
+                let items = self
+                    .component_type
+                    .items
+                    .values()
+                    .map(|item_within_component| unsafe {
+                        item_within_component.item_from_component(instance_ref.as_ptr())
+                    })
+                    .collect::<Vec<_>>();
+
+                window.free_graphics_resources(&Slice::from_slice(items.as_slice()));
             }
             None => {}
         }