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wip: think about dyn any for ScopeState

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Jonathan Kelley committed 2022-11-19 15:24:28 -08:00
1 parent 5253ce6b65
commit 12808ec0aa
5 files changed
+119 -139
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packages/core/src/scopes.rs
+87 -116
View File
@@ -1,14 +1,3 @@
use std::{
any::{Any, TypeId},
cell::{Cell, RefCell},
collections::{HashMap, HashSet},
rc::Rc,
sync::Arc,
};
use bumpalo::Bump;
use std::future::Future;
use crate::{
any_props::AnyProps,
arena::ElementId,
@@ -18,17 +7,40 @@ use crate::{
nodes::VNode,
TaskId,
};
use bumpalo::Bump;
use std::future::Future;
use std::{
any::{Any, TypeId},
cell::{Cell, RefCell},
collections::{HashMap, HashSet},
rc::Rc,
sync::Arc,
};
/// A wrapper around the [`Scoped`] object that contains a reference to the [`ScopeState`] and properties for a given
/// component.
///
/// The [`Scope`] is your handle to the [`VirtualDom`] and the component state. Every component is given its own
/// [`ScopeState`] and merged with its properties to create a [`Scoped`].
///
/// The [`Scope`] handle specifically exists to provide a stable reference to these items for the lifetime of the
/// component render.
pub type Scope<'a, T = ()> = &'a Scoped<'a, T>;
/// A wrapper around a component's [`ScopeState`] and properties. The [`ScopeState`] provides the majority of methods
/// for the VirtualDom and component state.
pub struct Scoped<'a, T = ()> {
/// The component's state and handle to the scheduler.
///
/// Stores things like the custom bump arena, spawn functions, hooks, and the scheduler.
pub scope: &'a ScopeState,
/// The component's properties.
pub props: &'a T,
}
impl<'a, T> std::ops::Deref for Scoped<'a, T> {
type Target = &'a ScopeState;
fn deref(&self) -> &Self::Target {
&self.scope
}
@@ -42,6 +54,9 @@ impl<'a, T> std::ops::Deref for Scoped<'a, T> {
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, PartialOrd, Ord)]
pub struct ScopeId(pub usize);
/// A component's state.
///
/// This struct stores all the important information about a component's state without the props.
pub struct ScopeState {
pub(crate) render_cnt: Cell<usize>,
@@ -55,7 +70,7 @@ pub struct ScopeState {
pub(crate) height: u32,
pub(crate) hook_arena: Bump,
pub(crate) hook_vals: RefCell<Vec<*mut dyn Any>>,
pub(crate) hook_list: RefCell<Vec<*mut dyn Any>>,
pub(crate) hook_idx: Cell<usize>,
pub(crate) shared_contexts: RefCell<HashMap<TypeId, Box<dyn Any>>>,
@@ -75,6 +90,7 @@ impl ScopeState {
_ => unreachable!(),
}
}
pub fn previous_frame(&self) -> &BumpFrame {
match self.render_cnt.get() % 2 {
1 => &self.node_arena_1,
@@ -83,10 +99,19 @@ impl ScopeState {
}
}
/// Get a handle to the currently active bump arena for this Scope
///
/// This is a bump memory allocator. Be careful using this directly since the contents will be wiped on the next render.
/// It's easy to leak memory here since the drop implementation will not be called for any objects allocated in this arena.
///
/// If you need to allocate items that need to be dropped, use bumpalo's box.
pub fn bump(&self) -> &Bump {
&self.current_frame().bump
}
/// Get a handle to the currently active head node arena for this Scope
///
/// This is useful for traversing the tree outside of the VirtualDom, such as in a custom renderer or in SSR.
pub fn root_node<'a>(&'a self) -> &'a VNode<'a> {
let r = unsafe { &*self.current_frame().node.get() };
unsafe { std::mem::transmute(r) }
@@ -166,6 +191,7 @@ impl ScopeState {
Arc::new(move |id| drop(chan.unbounded_send(SchedulerMsg::Immediate(id))))
}
/// Mark this scope as dirty, and schedule a render for it.
pub fn needs_update(&self) {
self.needs_update_any(self.scope_id());
}
@@ -180,6 +206,42 @@ impl ScopeState {
.expect("Scheduler to exist if scope exists");
}
/// Return any context of type T if it exists on this scope
pub fn has_context<T: 'static + Clone>(&self) -> Option<T> {
self.shared_contexts
.borrow()
.get(&TypeId::of::<T>())
.and_then(|shared| shared.downcast_ref::<T>())
.cloned()
}
/// Try to retrieve a shared state with type `T` from any parent scope.
///
/// The state will be cloned and returned, if it exists.
///
/// We recommend wrapping the state in an `Rc` or `Arc` to avoid deep cloning.
pub fn consume_context<T: 'static + Clone>(&self) -> Option<T> {
if let Some(this_ctx) = self.has_context() {
return Some(this_ctx);
}
let mut search_parent = self.parent;
while let Some(parent_ptr) = search_parent {
// safety: all parent pointers are valid thanks to the bump arena
let parent = unsafe { &*parent_ptr };
if let Some(shared) = parent.shared_contexts.borrow().get(&TypeId::of::<T>()) {
return Some(
shared
.downcast_ref::<T>()
.expect("Context of type T should exist")
.clone(),
);
}
search_parent = parent.parent;
}
None
}
/// This method enables the ability to expose state to children further down the [`VirtualDom`] Tree.
///
/// This is a "fundamental" operation and should only be called during initialization of a hook.
@@ -212,96 +274,6 @@ impl ScopeState {
value
}
/// Provide a context for the root component from anywhere in your app.
///
///
/// # Example
///
/// ```rust, ignore
/// struct SharedState(&'static str);
///
/// static App: Component = |cx| {
/// cx.use_hook(|| cx.provide_root_context(SharedState("world")));
/// render!(Child {})
/// }
///
/// static Child: Component = |cx| {
/// let state = cx.consume_state::<SharedState>();
/// render!(div { "hello {state.0}" })
/// }
/// ```
pub fn provide_root_context<T: 'static + Clone>(&self, value: T) -> T {
// if we *are* the root component, then we can just provide the context directly
if self.scope_id() == ScopeId(0) {
self.shared_contexts
.borrow_mut()
.insert(TypeId::of::<T>(), Box::new(value.clone()))
.and_then(|f| f.downcast::<T>().ok());
return value;
}
let mut search_parent = self.parent;
while let Some(parent) = search_parent.take() {
let parent = unsafe { &*parent };
if parent.scope_id() == ScopeId(0) {
let _ = parent
.shared_contexts
.borrow_mut()
.insert(TypeId::of::<T>(), Box::new(value.clone()));
return value;
}
search_parent = parent.parent;
}
unreachable!("all apps have a root scope")
}
/// Try to retrieve a shared state with type T from the any parent Scope.
pub fn consume_context<T: 'static + Clone>(&self) -> Option<T> {
if let Some(shared) = self.shared_contexts.borrow().get(&TypeId::of::<T>()) {
Some(
(*shared
.downcast_ref::<T>()
.expect("Context of type T should exist"))
.clone(),
)
} else {
let mut search_parent = self.parent;
while let Some(parent_ptr) = search_parent {
// safety: all parent pointers are valid thanks to the bump arena
let parent = unsafe { &*parent_ptr };
if let Some(shared) = parent.shared_contexts.borrow().get(&TypeId::of::<T>()) {
return Some(
shared
.downcast_ref::<T>()
.expect("Context of type T should exist")
.clone(),
);
}
search_parent = parent.parent;
}
None
}
}
/// Return any context of type T if it exists on this scope
pub fn has_context<T: 'static + Clone>(&self) -> Option<T> {
match self.shared_contexts.borrow().get(&TypeId::of::<T>()) {
Some(shared) => Some(
(*shared
.downcast_ref::<T>()
.expect("Context of type T should exist"))
.clone(),
),
None => None,
}
}
/// Pushes the future onto the poll queue to be polled after the component renders.
pub fn push_future(&self, fut: impl Future<Output = ()> + 'static) -> TaskId {
self.tasks.spawn(self.id, fut)
@@ -312,7 +284,7 @@ impl ScopeState {
self.push_future(fut);
}
/// Spawn a future that Dioxus will never clean up
/// Spawn a future that Dioxus won't clean up when this component is unmounted
///
/// This is good for tasks that need to be run after the component has been dropped.
pub fn spawn_forever(&self, fut: impl Future<Output = ()> + 'static) -> TaskId {
@@ -328,13 +300,14 @@ impl ScopeState {
id
}
/// Informs the scheduler that this task is no longer needed and should be removed
/// on next poll.
/// Informs the scheduler that this task is no longer needed and should be removed.
///
/// This drops the task immediately.
pub fn remove_future(&self, id: TaskId) {
self.tasks.remove(id);
}
/// Take a lazy [`VNode`] structure and actually build it with the context of the Vdoms efficient [`VNode`] allocator.
/// Take a lazy [`VNode`] structure and actually build it with the context of the efficient [`Bump`] allocator.
///
/// ## Example
///
@@ -369,19 +342,17 @@ impl ScopeState {
/// ```
#[allow(clippy::mut_from_ref)]
pub fn use_hook<State: 'static>(&self, initializer: impl FnOnce() -> State) -> &mut State {
let mut vals = self.hook_vals.borrow_mut();
let cur_hook = self.hook_idx.get();
let mut hook_list = self.hook_list.borrow_mut();
let hook_len = vals.len();
let cur_idx = self.hook_idx.get();
if cur_idx >= hook_len {
vals.push(self.hook_arena.alloc(initializer()));
if cur_hook >= hook_list.len() {
hook_list.push(self.hook_arena.alloc(initializer()));
}
vals
.get(cur_idx)
hook_list
.get(cur_hook)
.and_then(|inn| {
self.hook_idx.set(cur_idx + 1);
self.hook_idx.set(cur_hook + 1);
let raw_box = unsafe { &mut **inn };
raw_box.downcast_mut::<State>()
})