Prepare for optional inlining

Even if we make inlining optional, there are *some* situations where we just
need to do the inlining anyway to avoid
needless complexity.

sixtyfps_compiler/object_tree.rs

@@ -23,8 +23,8 @@ use crate::parser;
 use crate::parser::{syntax_nodes, SyntaxKind, SyntaxNode};
 use crate::typeloader::ImportedTypes;
 use crate::typeregister::TypeRegister;
-use std::cell::RefCell;
 use std::collections::btree_map::Entry;
+use std::cell::{Cell, RefCell};
 use std::collections::{BTreeMap, HashMap};
 use std::iter::FromIterator;
 use std::rc::{Rc, Weak};
@@ -225,6 +225,7 @@ pub struct Component {
     /// The names under which this component should be accessible
     /// if it is a global singleton and exported.
     pub exported_global_names: RefCell<Vec<ExportedName>>,
+    pub requires_inlining: Cell<bool>,
 }
 
 impl Component {

sixtyfps_compiler/passes.rs

@@ -67,55 +67,64 @@ pub async fn run_passes(
     check_public_api::check_public_api(doc, diag);
 
     collect_subcomponents::collect_subcomponents(root_component);
-    for component in root_component
+
+    let components = root_component
         .used_types
         .borrow()
         .sub_components
         .iter()
-        .chain(std::iter::once(root_component))
-    {
+        .cloned()
+        .chain(std::iter::once(root_component.clone()))
+        .collect::<Vec<_>>();
+
+    for component in &components {
         compile_paths::compile_paths(component, &doc.local_registry, diag);
         lower_tabwidget::lower_tabwidget(component, &mut type_loader, diag).await;
     }
 
     embed_images::embed_images(root_component, compiler_config.embed_resources, diag);
 
-    inlining::inline(doc);
-    focus_item::resolve_element_reference_in_set_focus_calls(root_component, diag);
-    focus_item::determine_initial_focus_item(root_component, diag);
-    focus_item::erase_forward_focus_properties(root_component);
-    flickable::handle_flickable(root_component, &global_type_registry.borrow());
-    lower_states::lower_states(root_component, &doc.local_registry, diag);
-    repeater_component::process_repeater_components(root_component);
-    lower_popups::lower_popups(root_component, &doc.local_registry, diag);
-    lower_layout::lower_layouts(root_component, &mut type_loader, diag).await;
-    z_order::reorder_by_z_order(root_component, diag);
-    lower_shadows::lower_shadow_properties(root_component, &doc.local_registry, diag);
-    clip::handle_clip(root_component, &global_type_registry.borrow(), diag);
-    transform_and_opacity::handle_transform_and_opacity(
-        root_component,
-        &global_type_registry.borrow(),
-        diag,
-    );
-    default_geometry::default_geometry(root_component, diag);
-    visible::handle_visible(root_component, &global_type_registry.borrow());
-    materialize_fake_properties::materialize_fake_properties(root_component);
-    ensure_window::ensure_window(root_component, &doc.local_registry);
-    apply_default_properties_from_style::apply_default_properties_from_style(
-        root_component,
-        &mut type_loader,
-        diag,
-    )
-    .await;
-    collect_globals::collect_globals(doc, diag);
-    unique_id::assign_unique_id(root_component);
-    binding_analysis::binding_analysis(root_component, diag);
+    inlining::inline(doc, inlining::InlineSelection::InlineOnlyRequiredComponents);
+
+    for component in &components {
+        focus_item::resolve_element_reference_in_set_focus_calls(component, diag);
+        focus_item::determine_initial_focus_item(component, diag);
+        focus_item::erase_forward_focus_properties(component);
+        flickable::handle_flickable(component, &global_type_registry.borrow());
+        lower_states::lower_states(component, &doc.local_registry, diag);
+        repeater_component::process_repeater_components(component);
+        lower_popups::lower_popups(component, &doc.local_registry, diag);
+        lower_layout::lower_layouts(component, &mut type_loader, diag).await;
+        z_order::reorder_by_z_order(component, diag);
+        lower_shadows::lower_shadow_properties(component, &doc.local_registry, diag);
+        clip::handle_clip(component, &global_type_registry.borrow(), diag);
+        transform_and_opacity::handle_transform_and_opacity(
+            component,
+            &global_type_registry.borrow(),
+            diag,
+        );
+        default_geometry::default_geometry(component, diag);
+        materialize_fake_properties::materialize_fake_properties(component);
+        apply_default_properties_from_style::apply_default_properties_from_style(
+            component,
+            &mut type_loader,
+            diag,
+        )
+        .await;
+        ensure_window::ensure_window(component, &doc.local_registry);
+        unique_id::assign_unique_id(component);
+        collect_globals::collect_globals(&doc, diag);
+
+        binding_analysis::binding_analysis(component, diag);
+    }
+
     deduplicate_property_read::deduplicate_property_read(root_component);
     optimize_useless_rectangles::optimize_useless_rectangles(root_component);
     move_declarations::move_declarations(root_component, diag);
     remove_aliases::remove_aliases(root_component, diag);
     resolve_native_classes::resolve_native_classes(root_component);
     remove_unused_properties::remove_unused_properties(root_component);
+
     collect_structs::collect_structs(root_component, diag);
     generate_item_indices::generate_item_indices(root_component);
     collect_custom_fonts::collect_custom_fonts(

sixtyfps_compiler/passes/collect_subcomponents.rs

@@ -44,6 +44,8 @@ fn collect_subcomponents_recursive(
             _ => return,
         };
         collect_subcomponents_recursive(&base_comp, result, hash);
-        result.push(base_comp);
+        if !base_comp.requires_inlining.get() {
+            result.push(base_comp);
+        }
     });
 }

sixtyfps_compiler/passes/default_geometry.rs

@@ -275,3 +275,31 @@ fn make_default_aspect_ratio_preserving_binding(
 
     elem.borrow_mut().bindings.insert(missing_size_property.to_string(), binding.into());
 }
+
+fn implicit_layout_info_call(elem: &ElementRc, orientation: Orientation) -> Expression {
+    Expression::FunctionCall {
+        function: Box::new(Expression::BuiltinFunctionReference(
+            BuiltinFunction::ImplicitLayoutInfo(orientation),
+            None,
+        )),
+        arguments: vec![Expression::ElementReference(Rc::downgrade(elem))],
+        source_location: None,
+    }
+}
+
+pub fn element_requires_parent_for_geometry(element: &ElementRc) -> bool {
+    for property in ["width", "height"] {
+        if !element.borrow().bindings.get(property).map_or(false, |b| b.ty() == Type::Percent) {
+            return true;
+        }
+    }
+    if let Type::Builtin(builtin_type) = &element.borrow().base_type {
+        if matches!(builtin_type.default_size_binding, DefaultSizeBinding::ExpandsToParentGeometry)
+        {
+            // FIXME: this does not apply to children of layouts
+            return true;
+        }
+    }
+
+    false
+}

sixtyfps_compiler/passes/flickable.rs

@@ -27,6 +27,10 @@ use crate::langtype::{NativeClass, Type};
 use crate::object_tree::{Component, Element, ElementRc};
 use crate::typeregister::TypeRegister;
 
+pub fn is_flickable_element(element: &ElementRc) -> bool {
+    matches!(&element.borrow().base_type, Type::Builtin(n) if n.name == "Flickable")
+}
+
 pub fn handle_flickable(root_component: &Rc<Component>, tr: &TypeRegister) {
     let mut native_rect = tr.lookup("Rectangle").as_builtin().native_class.clone();
     while let Some(p) = native_rect.parent.clone() {
@@ -37,7 +41,7 @@ pub fn handle_flickable(root_component: &Rc<Component>, tr: &TypeRegister) {
         root_component,
         &(),
         &mut |elem: &ElementRc, _| {
-            if !matches!(&elem.borrow().base_type, Type::Builtin(n) if n.name == "Flickable") {
+            if !is_flickable_element(elem) {
                 return;
             }
 

sixtyfps_compiler/passes/focus_item.rs

@@ -13,7 +13,7 @@ LICENSE END */
 use std::rc::Rc;
 
 use crate::diagnostics::{BuildDiagnostics, SourceLocation, Spanned};
-use crate::expression_tree::{BuiltinFunction, Expression};
+use crate::expression_tree::{BindingExpression, BuiltinFunction, Expression};
 use crate::langtype::Type;
 use crate::object_tree::*;
 
@@ -23,8 +23,19 @@ enum FocusCheckResult {
     ElementIsNotFocusable,
 }
 
+pub fn get_explicit_forward_focus(
+    element: &ElementRc,
+) -> Option<std::cell::Ref<BindingExpression>> {
+    let element = element.borrow();
+    if element.bindings.contains_key("forward_focus") {
+        Some(std::cell::Ref::map(element, |elem| &elem.bindings["forward_focus"]))
+    } else {
+        None
+    }
+}
+
 fn element_focus_check(element: &ElementRc) -> FocusCheckResult {
-    if let Some(forwarded_focus_binding) = element.borrow().bindings.get("forward-focus") {
+    if let Some(forwarded_focus_binding) = get_explicit_forward_focus(element) {
         if let Expression::ElementReference(target) = &forwarded_focus_binding.expression {
             return FocusCheckResult::FocusForwarded(
                 target.upgrade().unwrap(),

sixtyfps_compiler/passes/inlining.rs

@@ -17,19 +17,37 @@ use std::cell::RefCell;
 use std::collections::HashMap;
 use std::rc::Rc;
 
-pub fn inline(doc: &Document) {
-    fn inline_components_recursively(component: &Rc<Component>) {
+#[derive(Copy, Clone)]
+pub enum InlineSelection {
+    InlineAllComponents,
+    #[allow(dead_code)] // allow until it's an option globally used in the compiler
+    InlineOnlyRequiredComponents,
+}
+
+pub fn inline(doc: &Document, inline_selection: InlineSelection) {
+    fn inline_components_recursively(component: &Rc<Component>, inline_selection: InlineSelection) {
         recurse_elem(&component.root_element, &(), &mut |elem, _| {
             let base = elem.borrow().base_type.clone();
             if let Type::Component(c) = base {
                 // First, make sure that the component itself is properly inlined
-                inline_components_recursively(&c);
+                inline_components_recursively(&c, inline_selection);
                 // Inline this component.
-                inline_element(elem, &c, component);
+                if match inline_selection {
+                    InlineSelection::InlineAllComponents => true,
+                    InlineSelection::InlineOnlyRequiredComponents
+                        if component_requires_inlining(&c) =>
+                    {
+                        c.requires_inlining.set(true);
+                        true
+                    }
+                    _ => false,
+                } {
+                    inline_element(elem, &c, component);
+                }
             }
         })
     }
-    inline_components_recursively(&doc.root_component)
+    inline_components_recursively(&doc.root_component, inline_selection)
 }
 
 fn clone_tuple<U: Clone, V: Clone>((u, v): (&U, &V)) -> (U, V) {
@@ -261,3 +279,27 @@ fn duplicate_transition(
         node: t.node.clone(),
     }
 }
+
+// Some components need to be inlined to avoid increased complexity in handling them
+// in the code generators and subsequent passes.
+fn component_requires_inlining(component: &Rc<Component>) -> bool {
+    if component.child_insertion_point.borrow().is_some() {
+        return true;
+    }
+
+    let root_element = &component.root_element;
+    if super::flickable::is_flickable_element(root_element)
+        || super::focus_item::get_explicit_forward_focus(root_element).is_some()
+        || super::lower_layout::is_layout_element(root_element)
+    {
+        return true;
+    }
+
+    // For now any implicit bindings to the parent geometry require inlining, but this should
+    // be changed to instead create the bindings on the use-site instead.
+    if super::default_geometry::element_requires_parent_for_geometry(root_element) {
+        return true;
+    }
+
+    false
+}

sixtyfps_compiler/passes/lower_layout.rs

@@ -94,6 +94,10 @@ fn lower_element_layout(
     }
 }
 
+pub fn is_layout_element(element: &ElementRc) -> bool {
+    matches!(&element.borrow().base_type, Type::Builtin(n) if n.name == "GridLayout" || n.name == "HorizontalLayout" || n.name == "VerticalLayout" || n.name == "PathLayout")
+}
+
 fn lower_grid_layout(
     component: &Rc<Component>,
     grid_layout_element: &ElementRc,