dioxus/packages/core/examples/borrowed.rs
Jonathan Kelley 73047fe956 feat: props memoization is more powerful
This commit solves the memoization , properly memoizing properties that don't have any generic parameters. This is a rough heuristic to prevent non-static lifetimes from creeping into props and breaking our minual lifetime management.

Props that have a generic parameter are opted-out of the `partialeq` requirement and props *without* lifetimes must implement partialeq. We're going to leave manual disabling of memoization for future work.
2021-06-22 17:20:54 -04:00

74 lines
2 KiB
Rust

//! Demonstrate that borrowed data is possible as a property type
//! Borrowing (rather than cloning) is very important for speed and ergonomics.
//!
//! It's slightly more advanced than just cloning, but well worth the investment.
//!
//! If you use the FC macro, we handle the lifetimes automatically, making it easy to write efficient & performant components.
fn main() {}
use dioxus_core::prelude::*;
use std::rc::Rc;
struct AppProps {
items: Vec<Rc<ListItem>>,
}
#[derive(PartialEq)]
struct ListItem {
name: String,
age: u32,
}
fn app(ctx: Context<AppProps>) -> VNode {
let (val, set_val) = use_state(&ctx, || 0);
ctx.render(LazyNodes::new(move |_nodectx| {
builder::ElementBuilder::new(_nodectx, "div")
.iter_child({
ctx.items.iter().map(|child| {
builder::virtual_child(
_nodectx,
ChildItem,
ChildProps {
item: child.clone(),
item_handler: set_val.clone(),
},
None,
&[],
)
})
})
.iter_child([builder::ElementBuilder::new(_nodectx, "div")
.iter_child([builder::text3(_nodectx.bump(), format_args!("{}", val))])
.finish()])
.finish()
}))
}
// props should derive a partialeq implementation automatically, but implement ptr compare for & fields
struct ChildProps {
// Pass down complex structs
item: Rc<ListItem>,
// Even pass down handlers!
item_handler: Rc<dyn Fn(i32)>,
}
fn ChildItem<'a>(cx: Context<'a, ChildProps>) -> VNode {
cx.render(LazyNodes::new(move |__cx| todo!()))
}
impl PartialEq for ChildProps {
fn eq(&self, other: &Self) -> bool {
false
}
}
impl Properties for ChildProps {
type Builder = ();
fn builder() -> Self::Builder {
()
}
unsafe fn memoize(&self, other: &Self) -> bool {
self == other
}
}