slint/internal/compiler/passes/lower_component_container.rs

103 lines
3.6 KiB
Rust

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
//! This pass lowers `ComponentContainer`s.
//!
//! The `ComponentContainer` is lowered to something like this:
//!
//! ```slint
//! ComponentContainer {
//! if false: Emtpy {}
//! }
//! ```
//!
//! The Repeater that is inserted is where the ComponentContainer will embed
//! its `ItemTree` under. It is never evaluated as a conditional, so we should
//! be able to use some invalid expression, but that triggers asserts in later
//! compiler passes.
//!
//! The Repeater that is marked as `is_component_placeholder`, so that
//! we can generate the expected code later.
//!
//! The `Empty` behind the conditional `Repeater` is never used.
use crate::diagnostics::BuildDiagnostics;
use crate::langtype::ElementType;
use crate::typeloader::TypeLoader;
use crate::{expression_tree, object_tree::*};
use std::cell::RefCell;
use std::rc::Rc;
pub fn lower_component_container(
doc: &Document,
type_loader: &mut TypeLoader,
diag: &mut BuildDiagnostics,
) {
let empty_type = type_loader.global_type_registry.borrow().empty_type();
doc.visit_all_used_components(|component| {
recurse_elem_including_sub_components_no_borrow(component, &(), &mut |elem, _| {
if matches!(&elem.borrow().builtin_type(), Some(b) if b.name == "ComponentContainer") {
diagnose_component_container(elem, diag);
process_component_container(elem, &empty_type);
}
})
});
}
fn diagnose_component_container(element: &ElementRc, diag: &mut BuildDiagnostics) {
let elem = element.borrow();
if !elem.children.is_empty() {
diag.push_error("ComponentContainers may not have children".into(), &*element.borrow());
}
if let Some(cip) =
elem.enclosing_component.upgrade().unwrap().child_insertion_point.borrow().clone()
{
if Rc::ptr_eq(&cip.parent, element) {
diag.push_error(
"The @children placeholder cannot appear in a ComponentContainer".into(),
&*element.borrow(),
);
}
}
}
fn process_component_container(element: &ElementRc, empty_type: &ElementType) {
let suffix = element.borrow().id.clone();
let component = Rc::new_cyclic(|component_weak| {
let root_element = Rc::new(RefCell::new(Element {
id: smol_str::format_smolstr!("component_container_internal_{}", suffix),
base_type: empty_type.clone(),
enclosing_component: component_weak.clone(),
..Default::default()
}));
Component {
id: smol_str::format_smolstr!("ComponentContainerInternal_{}", suffix),
root_element,
..Default::default()
}
});
let mut elem = element.borrow_mut();
let embedded_element = Element::make_rc(Element {
base_type: ElementType::Component(component.clone()),
id: smol_str::format_smolstr!("component_container_placeholder_{}", suffix),
debug: elem.debug.clone(),
enclosing_component: elem.enclosing_component.clone(),
default_fill_parent: (true, true),
inline_depth: elem.inline_depth,
repeated: Some(RepeatedElementInfo {
model: expression_tree::Expression::BoolLiteral(false),
model_data_id: Default::default(),
index_id: Default::default(),
is_conditional_element: true,
is_listview: None,
}),
is_component_placeholder: true,
..Default::default()
});
elem.children.push(embedded_element);
}