Use ComponentRc during item tree traversal

This is in preparation for allowing the run-time / items to clone VRc's
of the component.

ComponentVTable functions like visit_children_item contine to take a
ComponentRefPin as "self" parameter type, as a VRc would not be
supported by rust right now. That means the implementation then uses
self_weak to obtain a strong self-reference.

api/sixtyfps-cpp/include/sixtyfps.h

@@ -62,6 +62,7 @@ using ComponentRef = vtable::VRef<private_api::ComponentVTable>;
 using ItemRef = vtable::VRef<private_api::ItemVTable>;
 using ItemVisitorRefMut = vtable::VRefMut<cbindgen_private::ItemVisitorVTable>;
 }
+using cbindgen_private::ComponentRc;
 using cbindgen_private::EasingCurve;
 using cbindgen_private::PropertyAnimation;
 using cbindgen_private::Slice;
@@ -174,7 +175,7 @@ using cbindgen_private::MouseEvent;
 using cbindgen_private::sixtyfps_visit_item_tree;
 namespace private_api {
 template<typename GetDynamic>
-inline InputEventResult process_input_event(ComponentRef component, int64_t &mouse_grabber,
+inline InputEventResult process_input_event(const ComponentRc &component_rc, int64_t &mouse_grabber,
                                             MouseEvent mouse_event, Slice<ItemTreeNode> tree,
                                             GetDynamic get_dynamic, const ComponentWindow *window,
                                             const ComponentRef *app_component)
@@ -182,7 +183,8 @@ inline InputEventResult process_input_event(ComponentRef component, int64_t &mou
     if (mouse_grabber != -1) {
         auto item_index = mouse_grabber & 0xffffffff;
         auto rep_index = mouse_grabber >> 32;
-        auto offset = cbindgen_private::sixtyfps_item_offset(component, tree, item_index);
+        auto offset =
+                cbindgen_private::sixtyfps_item_offset(component_rc.borrow(), tree, item_index);
         mouse_event.pos = { mouse_event.pos.x - offset.x, mouse_event.pos.y - offset.y };
         const auto &item_node = tree.ptr[item_index];
         InputEventResult result = InputEventResult::EventIgnored;
@@ -191,7 +193,7 @@ inline InputEventResult process_input_event(ComponentRef component, int64_t &mou
             result = item_node.item.item.vtable->input_event(
                     {
                             item_node.item.item.vtable,
-                            reinterpret_cast<char *>(component.instance)
+                            reinterpret_cast<char *>(component_rc.borrow().instance)
                                     + item_node.item.item.offset,
                     },
                     mouse_event, window, *app_component);
@@ -207,7 +209,7 @@ inline InputEventResult process_input_event(ComponentRef component, int64_t &mou
         return result;
     } else {
         return cbindgen_private::sixtyfps_process_ungrabbed_mouse_event(
-                component, mouse_event, window, *app_component, &mouse_grabber);
+                &component_rc, mouse_event, window, *app_component, &mouse_grabber);
     }
 }
 template<typename GetDynamic>
@@ -238,14 +240,14 @@ inline KeyEventResult process_key_event(ComponentRef component, int64_t focus_it
 }
 
 template<typename GetDynamic>
-inline FocusEventResult process_focus_event(ComponentRef component, int64_t &focus_item,
+inline FocusEventResult process_focus_event(const ComponentRc &component_rc, int64_t &focus_item,
                                             const FocusEvent *event, Slice<ItemTreeNode> tree,
                                             GetDynamic get_dynamic, const ComponentWindow *window)
 {
     switch (event->tag) {
     case FocusEvent::Tag::FocusIn:
-        return cbindgen_private::sixtyfps_locate_and_activate_focus_item(component, event, window,
+        return cbindgen_private::sixtyfps_locate_and_activate_focus_item(&component_rc, event,
-                                                                         &focus_item);
+                                                                         window, &focus_item);
     case FocusEvent::Tag::FocusOut:
         [[fallthrough]];
     case FocusEvent::Tag::WindowReceivedFocus:
@@ -260,7 +262,7 @@ inline FocusEventResult process_focus_event(ComponentRef component, int64_t &foc
                 item_node.item.item.vtable->focus_event(
                         {
                                 item_node.item.item.vtable,
-                                reinterpret_cast<char *>(component.instance)
+                                reinterpret_cast<char *>(component_rc.borrow().instance)
                                         + item_node.item.item.offset,
                         },
                         event, window);

api/sixtyfps-cpp/include/vtable.h

@@ -74,6 +74,8 @@ private:
         X data;
         Layout layout;
     };
+
+    void *data_ptr() { return reinterpret_cast<char *>(this) + data_offset; }
 };
 
 struct Dyn {};
@@ -120,6 +122,8 @@ public:
     }
 
     VRc<VTable, Dyn> into_dyn() const { return *reinterpret_cast<const VRc<VTable, Dyn> *>(this); }
+
+    VRef<VTable> borrow() const { return { inner->vtable, inner->data_ptr() }; }
 };
 
 template<typename VTable, typename X = Dyn>

sixtyfps_compiler/generator/cpp.rs

@@ -1020,7 +1020,8 @@ fn generate_component(
                     format!("    [[maybe_unused]] auto self = reinterpret_cast<const {}*>(base);", component_id),
                     format!("    switch(dyn_index) {{ {} }};", children_visitor_cases.join("")),
                     "    std::abort();\n};".to_owned(),
-                    "return sixtyfps::sixtyfps_visit_item_tree(component, item_tree() , index, order, visitor, dyn_visit);".to_owned(),
+                    format!("auto self_rc = reinterpret_cast<const {}*>(component.instance)->self_weak.lock()->into_dyn();", component_id),
+                    "return sixtyfps::sixtyfps_visit_item_tree(&self_rc, item_tree() , index, order, visitor, dyn_visit);".to_owned(),
                 ]),
                 ..Default::default()
             }),
@@ -1073,7 +1074,8 @@ fn generate_component(
                 is_static: true,
                 statements: Some(vec![
                     format!("auto self = reinterpret_cast<{}*>(component.instance);", component_id),
-                    "return sixtyfps::private_api::process_input_event(component, self->mouse_grabber, mouse_event, item_tree(), [self](int dyn_index, [[maybe_unused]] int rep_index) {".into(),
+                    "auto self_rc = self->self_weak.lock()->into_dyn();".into(),
+                    "return sixtyfps::private_api::process_input_event(self_rc, self->mouse_grabber, mouse_event, item_tree(), [self](int dyn_index, [[maybe_unused]] int rep_index) {".into(),
                     "    (void)self;".into(),
                     format!("    switch(dyn_index) {{ {} }};", repeated_input_branch.join("")),
                     "    return sixtyfps::private_api::ComponentRef{nullptr, nullptr};\n}, window, app_component);".into(),
@@ -1119,7 +1121,8 @@ fn generate_component(
                 is_static: true,
                 statements: Some(vec![
                     format!("auto self = reinterpret_cast<{}*>(component.instance);", component_id),
-                    "return sixtyfps::private_api::process_focus_event(component, self->focus_item, focus_event, item_tree(), [self](int dyn_index, [[maybe_unused]] int rep_index) {".into(),
+                    "auto self_rc = self->self_weak.lock()->into_dyn();".into(),
+                    "return sixtyfps::private_api::process_focus_event(self_rc, self->focus_item, focus_event, item_tree(), [self](int dyn_index, [[maybe_unused]] int rep_index) {".into(),
                     "    (void)self;".into(),
                     format!("    switch(dyn_index) {{ {} }};", repeated_input_branch.join("")),
                     "    return sixtyfps::private_api::ComponentRef{nullptr, nullptr};\n}, window);".into(),

sixtyfps_compiler/generator/rust.rs

@@ -651,7 +651,7 @@ fn generate_component(
                 -> sixtyfps::re_exports::VisitChildrenResult
             {
                 use sixtyfps::re_exports::*;
-                return sixtyfps::re_exports::visit_item_tree(self, VRef::new_pin(self), Self::item_tree(), index, order, visitor, visit_dynamic);
+                return sixtyfps::re_exports::visit_item_tree(self, &VRc::into_dyn(self.as_ref().self_weak.get().unwrap().upgrade().unwrap()), Self::item_tree(), index, order, visitor, visit_dynamic);
                 #[allow(unused)]
                 fn visit_dynamic(self_pinned: ::core::pin::Pin<&#component_id>, order: sixtyfps::re_exports::TraversalOrder, visitor: ItemVisitorRefMut, dyn_index: usize) -> VisitChildrenResult  {
                     let _self = self_pinned;
@@ -688,7 +688,7 @@ fn generate_component(
                         _ => (res, VisitChildrenResult::CONTINUE),
                     }
                 } else {
-                    process_ungrabbed_mouse_event(VRef::new_pin(self), mouse_event, window, app_component.clone())
+                    process_ungrabbed_mouse_event(&VRc::into_dyn(self.as_ref().self_weak.get().unwrap().upgrade().unwrap()), mouse_event, window, app_component.clone())
                 };
                 self.mouse_grabber.set(new_grab);
                 status
@@ -722,7 +722,7 @@ fn generate_component(
                 #[allow(unused)]
                 match event {
                     FocusEvent::FocusIn(_) => {
-                        let (event_result, visit_result) = locate_and_activate_focus_item(VRef::new_pin(self), event, window);
+                        let (event_result, visit_result) = locate_and_activate_focus_item(&VRc::into_dyn(self.as_ref().self_weak.get().unwrap().upgrade().unwrap()), event, window);
                         if event_result == FocusEventResult::FocusItemFound {
                             self.focus_item.set(visit_result)
                         }

sixtyfps_runtime/corelib/graphics.rs

@@ -609,8 +609,8 @@ impl<Backend: GraphicsBackend> crate::eventloop::GenericWindow for GraphicsWindo
     }
 
     fn draw(self: Rc<Self>) {
-        let component = self.component.borrow().upgrade().unwrap();
+        let component_rc = self.component.borrow().upgrade().unwrap();
-        let component = ComponentRc::borrow_pin(&component);
+        let component = ComponentRc::borrow_pin(&component_rc);
 
         {
             if self.layout_listener.as_ref().is_dirty() {
@@ -629,7 +629,7 @@ impl<Backend: GraphicsBackend> crate::eventloop::GenericWindow for GraphicsWindo
 
             // Generate cached rendering data once
             crate::item_tree::visit_items(
-                component,
+                &component_rc,
                 crate::item_tree::TraversalOrder::BackToFront,
                 |_, item, _| {
                     crate::item_rendering::update_item_rendering_data(
@@ -656,7 +656,7 @@ impl<Backend: GraphicsBackend> crate::eventloop::GenericWindow for GraphicsWindo
             &ARGBColor { red: 255 as u8, green: 255, blue: 255, alpha: 255 }.into(),
         );
         crate::item_rendering::render_component_items(
-            component,
+            &component_rc,
             &mut frame,
             &window.rendering_cache,
             &self,

sixtyfps_runtime/corelib/input.rs

@@ -11,7 +11,7 @@ LICENSE END */
 */
 #![warn(missing_docs)]
 
-use crate::component::ComponentRefPin;
+use crate::component::{ComponentRc, ComponentRefPin};
 use crate::graphics::Point;
 use crate::item_tree::{ItemVisitorResult, VisitChildrenResult};
 use euclid::default::Vector2D;
@@ -480,7 +480,7 @@ pub enum FocusEventResult {
 /// the focus_event (assuming it is of type FocusIn). Once located, the focus in
 /// even will also be dispatched to the item itself.
 pub fn locate_and_activate_focus_item(
-    component: ComponentRefPin,
+    component: &ComponentRc,
     focus_event: &FocusEvent,
     window: &crate::eventloop::ComponentWindow,
 ) -> (FocusEventResult, VisitChildrenResult) {
@@ -522,7 +522,7 @@ pub fn locate_and_activate_focus_item(
 /// * `component`: The component to deliver the event to.
 /// * `event`: The mouse event to deliver.
 pub fn process_ungrabbed_mouse_event(
-    component: ComponentRefPin,
+    component: &ComponentRc,
     event: MouseEvent,
     window: &crate::eventloop::ComponentWindow,
     app_component: ComponentRefPin,
@@ -596,7 +596,7 @@ pub(crate) mod ffi {
 
     #[no_mangle]
     pub extern "C" fn sixtyfps_process_ungrabbed_mouse_event(
-        component: core::pin::Pin<crate::component::ComponentRef>,
+        component: &ComponentRc,
         event: MouseEvent,
         window: &crate::eventloop::ComponentWindow,
         app_component: core::pin::Pin<crate::component::ComponentRef>,
@@ -620,7 +620,7 @@ pub(crate) mod ffi {
 
     #[no_mangle]
     pub extern "C" fn sixtyfps_locate_and_activate_focus_item(
-        component: core::pin::Pin<crate::component::ComponentRef>,
+        component: &ComponentRc,
         event: &FocusEvent,
         window: &crate::eventloop::ComponentWindow,
         new_focus_item: &mut crate::item_tree::VisitChildrenResult,

sixtyfps_runtime/corelib/item_rendering.rs

@@ -14,8 +14,10 @@ use super::graphics::{
     Frame, GraphicsBackend, GraphicsWindow, RenderingCache, RenderingPrimitivesBuilder,
 };
 use super::items::ItemRef;
+use crate::component::ComponentRc;
+use crate::eventloop::ComponentWindow;
 use crate::item_tree::ItemVisitorResult;
-use crate::{eventloop::ComponentWindow, slice::Slice};
+use crate::slice::Slice;
 use cgmath::{Matrix4, SquareMatrix, Vector3};
 use std::cell::{Cell, RefCell};
 
@@ -80,7 +82,7 @@ pub(crate) fn update_item_rendering_data<Backend: GraphicsBackend>(
 }
 
 pub(crate) fn render_component_items<Backend: GraphicsBackend>(
-    component: crate::component::ComponentRefPin,
+    component: &ComponentRc,
     frame: &mut Backend::Frame,
     rendering_cache: &RefCell<RenderingCache<Backend>>,
     window: &std::rc::Rc<GraphicsWindow<Backend>>,

sixtyfps_runtime/corelib/item_tree.rs

@@ -7,7 +7,7 @@
     This file is also available under commercial licensing terms.
     Please contact info@sixtyfps.io for more information.
 LICENSE END */
-use crate::component::{ComponentRefPin, ComponentVTable};
+use crate::component::{ComponentRc, ComponentVTable};
 use crate::graphics::Point;
 use crate::items::{ItemRef, ItemVTable};
 use core::pin::Pin;
@@ -106,7 +106,7 @@ pub struct ItemVisitorVTable {
     /// and `item` is a reference to the item itself
     visit_item: fn(
         VRefMut<ItemVisitorVTable>,
-        component: Pin<VRef<ComponentVTable>>,
+        component: &VRc<ComponentVTable, vtable::Dyn>,
         index: isize,
         item: Pin<VRef<ItemVTable>>,
     ) -> VisitChildrenResult,
@@ -117,12 +117,10 @@ pub struct ItemVisitorVTable {
 /// Type alias to `vtable::VRefMut<ItemVisitorVTable>`
 pub type ItemVisitorRefMut<'a> = vtable::VRefMut<'a, ItemVisitorVTable>;
 
-impl<T: FnMut(crate::component::ComponentRefPin, isize, Pin<ItemRef>) -> VisitChildrenResult>
+impl<T: FnMut(&ComponentRc, isize, Pin<ItemRef>) -> VisitChildrenResult> ItemVisitor for T {
-    ItemVisitor for T
-{
     fn visit_item(
         &mut self,
-        component: crate::component::ComponentRefPin,
+        component: &ComponentRc,
         index: isize,
         item: Pin<ItemRef>,
     ) -> VisitChildrenResult {
@@ -140,9 +138,9 @@ pub enum ItemVisitorResult<State> {
 ///
 /// Returns the index of the item that cancelled, or -1 if nobody cancelled
 pub fn visit_items<State>(
-    component: ComponentRefPin,
+    component: &ComponentRc,
     order: TraversalOrder,
-    mut visitor: impl FnMut(ComponentRefPin, Pin<ItemRef>, &State) -> ItemVisitorResult<State>,
+    mut visitor: impl FnMut(&ComponentRc, Pin<ItemRef>, &State) -> ItemVisitorResult<State>,
     state: State,
 ) -> VisitChildrenResult {
     visit_internal(
@@ -161,33 +159,33 @@ pub fn visit_items<State>(
 ///
 /// Returns the index of the item that cancelled, or -1 if nobody cancelled
 pub fn visit_items_with_post_visit<State, PostVisitState>(
-    component: ComponentRefPin,
+    component: &ComponentRc,
     order: TraversalOrder,
     mut visitor: impl FnMut(
-        ComponentRefPin,
+        &ComponentRc,
         Pin<ItemRef>,
         &State,
     ) -> (ItemVisitorResult<State>, PostVisitState),
-    mut post_visitor: impl FnMut(ComponentRefPin, Pin<ItemRef>, PostVisitState),
+    mut post_visitor: impl FnMut(&ComponentRc, Pin<ItemRef>, PostVisitState),
     state: State,
 ) -> VisitChildrenResult {
     visit_internal(component, order, &mut visitor, &mut post_visitor, -1, &state)
 }
 
 fn visit_internal<State, PostVisitState>(
-    component: ComponentRefPin,
+    component: &ComponentRc,
     order: TraversalOrder,
     visitor: &mut impl FnMut(
-        ComponentRefPin,
+        &ComponentRc,
         Pin<ItemRef>,
         &State,
     ) -> (ItemVisitorResult<State>, PostVisitState),
-    post_visitor: &mut impl FnMut(ComponentRefPin, Pin<ItemRef>, PostVisitState),
+    post_visitor: &mut impl FnMut(&ComponentRc, Pin<ItemRef>, PostVisitState),
     index: isize,
     state: &State,
 ) -> VisitChildrenResult {
     let mut actual_visitor =
-        |component: ComponentRefPin, index: isize, item: Pin<ItemRef>| -> VisitChildrenResult {
+        |component: &ComponentRc, index: isize, item: Pin<ItemRef>| -> VisitChildrenResult {
             match visitor(component, item, state) {
                 (ItemVisitorResult::Continue(state), post_visit_state) => {
                     let result =
@@ -199,7 +197,7 @@ fn visit_internal<State, PostVisitState>(
             }
         };
     vtable::new_vref!(let mut actual_visitor : VRefMut<ItemVisitorVTable> for ItemVisitor = &mut actual_visitor);
-    component.as_ref().visit_children_item(index, order, actual_visitor)
+    VRc::borrow_pin(component).as_ref().visit_children_item(index, order, actual_visitor)
 }
 
 /// Visit the children within an array of ItemTreeNode
@@ -212,7 +210,7 @@ fn visit_internal<State, PostVisitState>(
 /// Possibly we should generate code that directly call the visitor instead
 pub fn visit_item_tree<Base>(
     base: Pin<&Base>,
-    component: ComponentRefPin,
+    component: &ComponentRc,
     item_tree: &[ItemTreeNode<Base>],
     index: isize,
     order: TraversalOrder,
@@ -307,7 +305,7 @@ pub(crate) mod ffi {
     /// Safety: Assume a correct implementation of the item_tree array
     #[no_mangle]
     pub unsafe extern "C" fn sixtyfps_visit_item_tree(
-        component: Pin<VRef<ComponentVTable>>,
+        component: &ComponentRc,
         item_tree: Slice<ItemTreeNode<u8>>,
         index: isize,
         order: TraversalOrder,
@@ -320,7 +318,7 @@ pub(crate) mod ffi {
         ) -> VisitChildrenResult,
     ) -> VisitChildrenResult {
         crate::item_tree::visit_item_tree(
-            Pin::new_unchecked(&*(component.as_ptr() as *const u8)),
+            Pin::new_unchecked(&*(&**component as *const Dyn as *const u8)),
             component,
             item_tree.as_slice(),
             index,

sixtyfps_runtime/interpreter/dynamic_component.rs

@@ -336,9 +336,10 @@ extern "C" fn visit_children_item(
 ) -> VisitChildrenResult {
     generativity::make_guard!(guard);
     let instance_ref = unsafe { InstanceRef::from_pin_ref(component, guard) };
+    let comp_rc = instance_ref.self_weak().get().unwrap().upgrade().unwrap();
     sixtyfps_corelib::item_tree::visit_item_tree(
         instance_ref.instance,
-        component,
+        &vtable::VRc::into_dyn(comp_rc),
         instance_ref.component_type.item_tree.as_slice().into(),
         index,
         order,
@@ -1014,6 +1015,7 @@ pub fn instantiate<'id>(
             );
         }
     }
+
     comp_rc
 }
 
@@ -1459,8 +1461,12 @@ extern "C" fn input_event(
             _ => (res, VisitChildrenResult::CONTINUE),
         }
     } else {
+        generativity::make_guard!(guard);
+        let instance_ref = unsafe { InstanceRef::from_pin_ref(component, guard) };
+        let comp_rc = instance_ref.self_weak().get().unwrap().upgrade().unwrap();
+
         sixtyfps_corelib::input::process_ungrabbed_mouse_event(
-            component,
+            &vtable::VRc::into_dyn(comp_rc),
             mouse_event,
             window,
             app_component.clone(),
@@ -1508,8 +1514,16 @@ extern "C" fn focus_event(
 
     match event {
         FocusEvent::FocusIn(_) => {
+            generativity::make_guard!(guard);
+            let instance_ref = unsafe { InstanceRef::from_pin_ref(component, guard) };
+            let comp_rc = instance_ref.self_weak().get().unwrap().upgrade().unwrap();
+
             let (event_result, visit_result) =
-                sixtyfps_corelib::input::locate_and_activate_focus_item(component, event, window);
+                sixtyfps_corelib::input::locate_and_activate_focus_item(
+                    &vtable::VRc::into_dyn(comp_rc),
+                    event,
+                    window,
+                );
             if event_result == FocusEventResult::FocusItemFound {
                 extra_data.focus_item.set(visit_result)
             }