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|
use crate::widget::Element;
use std::any::{self, Any};
pub struct Tree {
pub tag: any::TypeId,
pub state: Box<dyn Any>,
pub children: Vec<Tree>,
}
impl Tree {
pub fn empty() -> Self {
Self {
tag: any::TypeId::of::<()>(),
state: Box::new(()),
children: Vec::new(),
}
}
pub fn new<Message, Renderer>(
element: &Element<'_, Message, Renderer>,
) -> Self {
Self {
tag: element.as_widget().tag(),
state: element.as_widget().state(),
children: element
.as_widget()
.children()
.iter()
.map(Self::new)
.collect(),
}
}
pub fn diff<Message, Renderer>(
&mut self,
new: &Element<'_, Message, Renderer>,
) {
if self.tag == new.as_widget().tag() {
let new_children = new.as_widget().children();
if self.children.len() > new_children.len() {
self.children.truncate(new_children.len());
}
for (child_state, new) in
self.children.iter_mut().zip(new_children.iter())
{
child_state.diff(new);
}
if self.children.len() < new_children.len() {
self.children.extend(
new_children[self.children.len()..].iter().map(Self::new),
);
}
} else {
*self = Self::new(new);
}
}
}
|
