use crate::{
any_props::AnyProps,
any_props::VProps,
arena::ElementId,
bump_frame::BumpFrame,
innerlude::{DynamicNode, EventHandler, VComponent, VText},
innerlude::{ErrorBoundary, Scheduler, SchedulerMsg},
lazynodes::LazyNodes,
nodes::{ComponentReturn, IntoAttributeValue, IntoDynNode, RenderReturn},
AnyValue, Attribute, AttributeValue, Element, Event, Properties, TaskId,
};
use bumpalo::{boxed::Box as BumpBox, Bump};
use bumpslab::{BumpSlab, Slot};
use rustc_hash::{FxHashMap, FxHashSet};
use slab::{Slab, VacantEntry};
use std::{
any::{Any, TypeId},
cell::{Cell, RefCell},
fmt::{Arguments, Debug},
future::Future,
ops::{Index, IndexMut},
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 [`crate::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>;
// This ScopedType exists because we want to limit the amount of monomorphization that occurs when making inner
// state type generic over props. When the state is generic, it causes every method to be monomorphized for every
// instance of Scope<T> in the codebase.
//
//
/// 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
}
}
/// A component's unique identifier.
///
/// `ScopeId` is a `usize` that acts a key for the internal slab of Scopes. This means that the key is not unqiue across
/// time. We do try and guarantee that between calls to `wait_for_work`, no ScopeIds will be recycled in order to give
/// time for any logic that relies on these IDs to properly update.
#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, PartialOrd, Ord)]
pub struct ScopeId(pub usize);
/// A thin wrapper around a BumpSlab that uses ids to index into the slab.
pub(crate) struct ScopeSlab {
slab: BumpSlab<ScopeState>,
// a slab of slots of stable pointers to the ScopeState in the bump slab
entries: Slab<Slot<'static, ScopeState>>,
}
impl Drop for ScopeSlab {
fn drop(&mut self) {
// Bump slab doesn't drop its contents, so we need to do it manually
for slot in self.entries.drain() {
self.slab.remove(slot);
}
}
}
impl Default for ScopeSlab {
fn default() -> Self {
Self {
slab: BumpSlab::new(),
entries: Slab::new(),
}
}
}
impl ScopeSlab {
pub(crate) fn get(&self, id: ScopeId) -> Option<&ScopeState> {
self.entries.get(id.0).map(|slot| unsafe { &*slot.ptr() })
}
pub(crate) fn get_mut(&mut self, id: ScopeId) -> Option<&mut ScopeState> {
self.entries
.get(id.0)
.map(|slot| unsafe { &mut *slot.ptr_mut() })
}
pub(crate) fn vacant_entry(&mut self) -> ScopeSlabEntry {
let entry = self.entries.vacant_entry();
ScopeSlabEntry {
slab: &mut self.slab,
entry,
}
}
pub(crate) fn remove(&mut self, id: ScopeId) {
self.slab.remove(self.entries.remove(id.0));
}
pub(crate) fn contains(&self, id: ScopeId) -> bool {
self.entries.contains(id.0)
}
pub(crate) fn iter(&self) -> impl Iterator<Item = &ScopeState> {
self.entries.iter().map(|(_, slot)| unsafe { &*slot.ptr() })
}
}
pub(crate) struct ScopeSlabEntry<'a> {
slab: &'a mut BumpSlab<ScopeState>,
entry: VacantEntry<'a, Slot<'static, ScopeState>>,
}
impl<'a> ScopeSlabEntry<'a> {
pub(crate) fn key(&self) -> ScopeId {
ScopeId(self.entry.key())
}
pub(crate) fn insert(self, scope: ScopeState) -> &'a ScopeState {
let slot = self.slab.push(scope);
// this is safe because the slot is only ever accessed with the lifetime of the borrow of the slab
let slot = unsafe { std::mem::transmute(slot) };
let entry = self.entry.insert(slot);
unsafe { &*entry.ptr() }
}
}
impl Index<ScopeId> for ScopeSlab {
type Output = ScopeState;
fn index(&self, id: ScopeId) -> &Self::Output {
self.get(id).unwrap()
}
}
impl IndexMut<ScopeId> for ScopeSlab {
fn index_mut(&mut self, id: ScopeId) -> &mut Self::Output {
self.get_mut(id).unwrap()
}
}
/// A component's state separate from its props.
///
/// This struct exists to provide a common interface for all scopes without relying on generics.
pub struct ScopeState {
pub(crate) render_cnt: Cell<usize>,
pub(crate) name: &'static str,
pub(crate) node_arena_1: BumpFrame,
pub(crate) node_arena_2: BumpFrame,
pub(crate) parent: Option<*const ScopeState>,
pub(crate) id: ScopeId,
pub(crate) height: u32,
pub(crate) hook_arena: Bump,
pub(crate) hook_list: RefCell<Vec<*mut dyn Any>>,
pub(crate) hook_idx: Cell<usize>,
pub(crate) shared_contexts: RefCell<FxHashMap<TypeId, Box<dyn Any>>>,
pub(crate) tasks: Rc<Scheduler>,
pub(crate) spawned_tasks: RefCell<FxHashSet<TaskId>>,
pub(crate) borrowed_props: RefCell<Vec<*const VComponent<'static>>>,
pub(crate) attributes_to_drop: RefCell<Vec<*const Attribute<'static>>>,
pub(crate) props: Option<Box<dyn AnyProps<'static>>>,
pub(crate) placeholder: Cell<Option<ElementId>>,
}
impl<'src> ScopeState {
pub(crate) fn current_frame(&self) -> &BumpFrame {
match self.render_cnt.get() % 2 {
0 => &self.node_arena_1,
1 => &self.node_arena_2,
_ => unreachable!(),
}
}
pub(crate) fn previous_frame(&self) -> &BumpFrame {
match self.render_cnt.get() % 2 {
1 => &self.node_arena_1,
0 => &self.node_arena_2,
_ => unreachable!(),
}
}
/// Get the name of this component
pub fn name(&self) -> &str {
self.name
}
/// Get the current render since the inception of this component
///
/// This can be used as a helpful diagnostic when debugging hooks/renders, etc
pub fn generation(&self) -> usize {
self.render_cnt.get()
}
/// 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 {
// note that this is actually the previous frame since we use that as scratch space while the component is rendering
self.previous_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.
///
/// Panics if the tree has not been built yet.
pub fn root_node(&self) -> &RenderReturn {
self.try_root_node()
.expect("The tree has not been built yet. Make sure to call rebuild on the tree before accessing its nodes.")
}
/// Try to 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.
///
/// Returns [`None`] if the tree has not been built yet.
pub fn try_root_node(&self) -> Option<&RenderReturn> {
let ptr = self.current_frame().node.get();
if ptr.is_null() {
return None;
}
let r: &RenderReturn = unsafe { &*ptr };
unsafe { std::mem::transmute(r) }
}
/// Get the height of this Scope - IE the number of scopes above it.
///
/// A Scope with a height of `0` is the root scope - there are no other scopes above it.
///
/// # Example
///
/// ```rust, ignore
/// let mut dom = VirtualDom::new(|cx| cx.render(rsx!{ div {} }));
/// dom.rebuild();
///
/// let base = dom.base_scope();
///
/// assert_eq!(base.height(), 0);
/// ```
pub fn height(&self) -> u32 {
self.height
}
/// Get the Parent of this [`Scope`] within this Dioxus [`crate::VirtualDom`].
///
/// This ID is not unique across Dioxus [`crate::VirtualDom`]s or across time. IDs will be reused when components are unmounted.
///
/// The base component will not have a parent, and will return `None`.
///
/// # Example
///
/// ```rust, ignore
/// let mut dom = VirtualDom::new(|cx| cx.render(rsx!{ div {} }));
/// dom.rebuild();
///
/// let base = dom.base_scope();
///
/// assert_eq!(base.parent(), None);
/// ```
pub fn parent(&self) -> Option<ScopeId> {
// safety: the pointer to our parent is *always* valid thanks to the bump arena
self.parent.map(|p| unsafe { &*p }.id)
}
/// Get the ID of this Scope within this Dioxus [`crate::VirtualDom`].
///
/// This ID is not unique across Dioxus [`crate::VirtualDom`]s or across time. IDs will be reused when components are unmounted.
///
/// # Example
///
/// ```rust, ignore
/// let mut dom = VirtualDom::new(|cx| cx.render(rsx!{ div {} }));
/// dom.rebuild();
/// let base = dom.base_scope();
///
/// assert_eq!(base.scope_id(), 0);
/// ```
pub fn scope_id(&self) -> ScopeId {
self.id
}
/// Create a subscription that schedules a future render for the reference component
///
/// ## Notice: you should prefer using [`Self::schedule_update_any`] and [`Self::scope_id`]
pub fn schedule_update(&self) -> Arc<dyn Fn() + Send + Sync + 'static> {
let (chan, id) = (self.tasks.sender.clone(), self.scope_id());
Arc::new(move || drop(chan.unbounded_send(SchedulerMsg::Immediate(id))))
}
/// Schedule an update for any component given its [`ScopeId`].
///
/// A component's [`ScopeId`] can be obtained from `use_hook` or the [`ScopeState::scope_id`] method.
///
/// This method should be used when you want to schedule an update for a component
pub fn schedule_update_any(&self) -> Arc<dyn Fn(ScopeId) + Send + Sync> {
let chan = self.tasks.sender.clone();
Arc::new(move |id| {
chan.unbounded_send(SchedulerMsg::Immediate(id)).unwrap();
})
}
/// Mark this scope as dirty, and schedule a render for it.
pub fn needs_update(&self) {
self.needs_update_any(self.scope_id());
}
/// Get the [`ScopeId`] of a mounted component.
///
/// `ScopeId` is not unique for the lifetime of the [`crate::VirtualDom`] - a [`ScopeId`] will be reused if a component is unmounted.
pub fn needs_update_any(&self, id: ScopeId) {
self.tasks
.sender
.unbounded_send(SchedulerMsg::Immediate(id))
.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>())?
.downcast_ref::<T>()
.cloned()
}
/// Try to retrieve a shared state with type `T` from any parent scope.
///
/// Clones the state if it exists.
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 shared.downcast_ref::<T>().cloned();
}
search_parent = parent.parent;
}
None
}
/// Expose state to children further down the [`crate::VirtualDom`] Tree. Does not require `clone` on the context,
/// though we do recommend it.
///
/// This is a "fundamental" operation and should only be called during initialization of a hook.
///
/// For a hook that provides the same functionality, use `use_provide_context` and `use_context` instead.
///
/// If a state is provided that already exists, the new value will not be inserted. Instead, this method will
/// return the existing value. This behavior is chosen so shared values do not need to be `Clone`. This particular
/// behavior might change in the future.
///
/// # Example
///
/// ```rust, ignore
/// struct SharedState(&'static str);
///
/// static App: Component = |cx| {
/// cx.use_hook(|| cx.provide_context(SharedState("world")));
/// render!(Child {})
/// }
///
/// static Child: Component = |cx| {
/// let state = cx.consume_state::<SharedState>();
/// render!(div { "hello {state.0}" })
/// }
/// ```
pub fn provide_context<T: 'static + Clone>(&self, value: T) -> T {
let value2 = value.clone();
self.shared_contexts
.borrow_mut()
.insert(TypeId::of::<T>(), Box::new(value));
value2
}
/// 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 {
let id = self.tasks.spawn(self.id, fut);
self.spawned_tasks.borrow_mut().insert(id);
id
}
/// Spawns the future but does not return the [`TaskId`]
pub fn spawn(&self, fut: impl Future<Output = ()> + 'static) {
self.push_future(fut);
}
/// 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 {
// The root scope will never be unmounted so we can just add the task at the top of the app
let id = self.tasks.spawn(ScopeId(0), fut);
// wake up the scheduler if it is sleeping
self.tasks
.sender
.unbounded_send(SchedulerMsg::TaskNotified(id))
.expect("Scheduler should exist");
self.spawned_tasks.borrow_mut().insert(id);
id
}
/// 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 [`crate::VNode`] structure and actually build it with the context of the efficient [`bumpalo::Bump`] allocator.
///
/// ## Example
///
/// ```ignore
/// fn Component(cx: Scope<Props>) -> Element {
/// // Lazy assemble the VNode tree
/// let lazy_nodes = rsx!("hello world");
///
/// // Actually build the tree and allocate it
/// cx.render(lazy_tree)
/// }
///```
pub fn render(&'src self, rsx: LazyNodes<'src, '_>) -> Element<'src> {
let element = rsx.call(self);
let mut listeners = self.attributes_to_drop.borrow_mut();
for attr in element.dynamic_attrs {
match attr.value {
AttributeValue::Any(_) | AttributeValue::Listener(_) => {
let unbounded = unsafe { std::mem::transmute(attr as *const Attribute) };
listeners.push(unbounded);
}
_ => (),
}
}
let mut props = self.borrowed_props.borrow_mut();
for node in element.dynamic_nodes {
if let DynamicNode::Component(comp) = node {
let unbounded = unsafe { std::mem::transmute(comp as *const VComponent) };
props.push(unbounded);
}
}
Some(element)
}
/// Create a dynamic text node using [`Arguments`] and the [`ScopeState`]'s internal [`Bump`] allocator
pub fn text_node(&'src self, args: Arguments) -> DynamicNode<'src> {
DynamicNode::Text(VText {
value: self.raw_text(args),
id: Default::default(),
})
}
/// Allocate some text inside the [`ScopeState`] from [`Arguments`]
///
/// Uses the currently active [`Bump`] allocator
pub fn raw_text(&'src self, args: Arguments) -> &'src str {
args.as_str().unwrap_or_else(|| {
use bumpalo::core_alloc::fmt::Write;
let mut str_buf = bumpalo::collections::String::new_in(self.bump());
str_buf.write_fmt(args).unwrap();
str_buf.into_bump_str()
})
}
/// Convert any item that implements [`IntoDynNode`] into a [`DynamicNode`] using the internal [`Bump`] allocator
pub fn make_node<'c, I>(&'src self, into: impl IntoDynNode<'src, I> + 'c) -> DynamicNode {
into.into_vnode(self)
}
/// Create a new [`Attribute`] from a name, value, namespace, and volatile bool
///
/// "Volatile" referes to whether or not Dioxus should always override the value. This helps prevent the UI in
/// some renderers stay in sync with the VirtualDom's understanding of the world
pub fn attr(
&'src self,
name: &'static str,
value: impl IntoAttributeValue<'src>,
namespace: Option<&'static str>,
volatile: bool,
) -> Attribute<'src> {
Attribute {
name,
namespace,
volatile,
mounted_element: Default::default(),
value: value.into_value(self.bump()),
}
}
/// Create a new [`DynamicNode::Component`] variant
///
///
/// The given component can be any of four signatures. Remember that an [`Element`] is really a [`Result<VNode>`].
///
/// ```rust, ignore
/// // Without explicit props
/// fn(Scope) -> Element;
/// async fn(Scope<'_>) -> Element;
///
/// // With explicit props
/// fn(Scope<Props>) -> Element;
/// async fn(Scope<Props<'_>>) -> Element;
/// ```
pub fn component<P, A, F: ComponentReturn<'src, A>>(
&'src self,
component: fn(Scope<'src, P>) -> F,
props: P,
fn_name: &'static str,
) -> DynamicNode<'src>
where
P: Properties + 'src,
{
let vcomp = VProps::new(component, P::memoize, props);
// cast off the lifetime of the render return
let as_dyn: Box<dyn AnyProps<'src> + '_> = Box::new(vcomp);
let extended: Box<dyn AnyProps<'src> + 'src> = unsafe { std::mem::transmute(as_dyn) };
DynamicNode::Component(VComponent {
name: fn_name,
render_fn: component as *const (),
static_props: P::IS_STATIC,
props: RefCell::new(Some(extended)),
scope: Cell::new(None),
})
}
/// Create a new [`EventHandler`] from an [`FnMut`]
pub fn event_handler<T>(&'src self, f: impl FnMut(T) + 'src) -> EventHandler<'src, T> {
let handler: &mut dyn FnMut(T) = self.bump().alloc(f);
let caller = unsafe { BumpBox::from_raw(handler as *mut dyn FnMut(T)) };
let callback = RefCell::new(Some(caller));
EventHandler { callback }
}
/// Create a new [`AttributeValue`] with the listener variant from a callback
///
/// The callback must be confined to the lifetime of the ScopeState
pub fn listener<T: 'static>(
&'src self,
mut callback: impl FnMut(Event<T>) + 'src,
) -> AttributeValue<'src> {
// safety: there's no other way to create a dynamicly-dispatched bump box other than alloc + from-raw
// This is the suggested way to build a bumpbox
//
// In theory, we could just use regular boxes
let boxed: BumpBox<'src, dyn FnMut(_) + 'src> = unsafe {
BumpBox::from_raw(self.bump().alloc(move |event: Event<dyn Any>| {
if let Ok(data) = event.data.downcast::<T>() {
callback(Event {
propagates: event.propagates,
data,
})
}
}))
};
AttributeValue::Listener(RefCell::new(Some(boxed)))
}
/// Create a new [`AttributeValue`] with a value that implements [`AnyValue`]
pub fn any_value<T: AnyValue>(&'src self, value: T) -> AttributeValue<'src> {
// safety: there's no other way to create a dynamicly-dispatched bump box other than alloc + from-raw
// This is the suggested way to build a bumpbox
//
// In theory, we could just use regular boxes
let boxed: BumpBox<'src, dyn AnyValue> =
unsafe { BumpBox::from_raw(self.bump().alloc(value)) };
AttributeValue::Any(RefCell::new(Some(boxed)))
}
/// Inject an error into the nearest error boundary and quit rendering
///
/// The error doesn't need to implement Error or any specific traits since the boundary
/// itself will downcast the error into a trait object.
pub fn throw(&self, error: impl Debug + 'static) -> Option<()> {
if let Some(cx) = self.consume_context::<Rc<ErrorBoundary>>() {
cx.insert_error(self.scope_id(), Box::new(error));
}
// Always return none during a throw
None
}
/// Store a value between renders. The foundational hook for all other hooks.
///
/// Accepts an `initializer` closure, which is run on the first use of the hook (typically the initial render). The return value of this closure is stored for the lifetime of the component, and a mutable reference to it is provided on every render as the return value of `use_hook`.
///
/// When the component is unmounted (removed from the UI), the value is dropped. This means you can return a custom type and provide cleanup code by implementing the [`Drop`] trait
///
/// # Example
///
/// ```
/// use dioxus_core::ScopeState;
///
/// // prints a greeting on the initial render
/// pub fn use_hello_world(cx: &ScopeState) {
/// cx.use_hook(|| println!("Hello, world!"));
/// }
/// ```
#[allow(clippy::mut_from_ref)]
pub fn use_hook<State: 'static>(&self, initializer: impl FnOnce() -> State) -> &mut State {
let cur_hook = self.hook_idx.get();
let mut hook_list = self.hook_list.try_borrow_mut().expect("The hook list is already borrowed: This error is likely caused by trying to use a hook inside a hook which violates the rules of hooks.");
if cur_hook >= hook_list.len() {
hook_list.push(self.hook_arena.alloc(initializer()));
}
hook_list
.get(cur_hook)
.and_then(|inn| {
self.hook_idx.set(cur_hook + 1);
let raw_box = unsafe { &mut **inn };
raw_box.downcast_mut::<State>()
})
.expect(
r###"
Unable to retrieve the hook that was initialized at this index.
Consult the `rules of hooks` to understand how to use hooks properly.
You likely used the hook in a conditional. Hooks rely on consistent ordering between renders.
Functions prefixed with "use" should never be called conditionally.
"###,
)
}
}