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wip: more changes to scheduler

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Jonathan Kelley committed 2021-11-06 23:23:56 -04:00
1 parent 2933e4bc11
commit 059294ab55
3 files changed
+229 -255
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packages/core/architecture.md
+31
View File
@@ -170,3 +170,34 @@ do anything too arduous from onInput.
For the rest, we defer to the rIC period and work down each queue from high to low. For the rest, we defer to the rIC period and work down each queue from high to low.
*/ */
Strategy:
- When called, check for any UI events that might've been received since the last frame.
- Dump all UI events into a "pending discrete" queue and a "pending continuous" queue.
- If there are any pending discrete events, then elevate our priority level. If our priority level is already "high,"
then we need to finish the high priority work first. If the current work is "low" then analyze what scopes
will be invalidated by this new work. If this interferes with any in-flight medium or low work, then we need
to bump the other work out of the way, or choose to process it so we don't have any conflicts.
'static components have a leg up here since their work can be re-used among multiple scopes.
"High priority" is only for blocking! Should only be used on "clicks"
- If there are no pending discrete events, then check for continuous events. These can be completely batched
- we batch completely until we run into a discrete event
- all continuous events are batched together
- so D C C C C C would be two separate events - D and C. IE onclick and onscroll
- D C C C C C C D C C C D would be D C D C D in 5 distinct phases.
- !listener bubbling is not currently implemented properly and will need to be implemented somehow in the future
- we need to keep track of element parents to be able to traverse properly
Open questions:
- what if we get two clicks from the component during the same slice?
- should we batch?
- react says no - they are continuous
- but if we received both - then we don't need to diff, do we? run as many as we can and then finally diff?
packages/core/src/virtual_dom.rs
+194 -252
View File
@@ -242,27 +242,6 @@ impl VirtualDom {
// Methods to actually run the VirtualDOM // Methods to actually run the VirtualDOM
impl VirtualDom { impl VirtualDom {
/// Performs a *full* rebuild of the virtual dom, returning every edit required to generate the actual dom from scratch
///
/// The diff machine expects the RealDom's stack to be the root of the application.
///
/// Tasks will not be polled with this method, nor will any events be processed from the event queue. Instead, the
/// root component will be ran once and then diffed. All updates will flow out as mutations.
///
/// All state stored in components will be completely wiped away.
///
/// # Example
/// ```
/// static App: FC<()> = |(cx, props)| cx.render(rsx!{ "hello world" });
/// let mut dom = VirtualDom::new();
/// let edits = dom.rebuild();
///
/// apply_edits(edits);
/// ```
pub fn rebuild(&mut self) -> Mutations {
self.hard_diff(&self.base_scope)
}
/// Waits for the scheduler to have work /// Waits for the scheduler to have work
/// This lets us poll async tasks during idle periods without blocking the main thread. /// This lets us poll async tasks during idle periods without blocking the main thread.
pub async fn wait_for_work(&mut self) { pub async fn wait_for_work(&mut self) {
@@ -373,71 +352,122 @@ impl VirtualDom {
&'a mut self, &'a mut self,
mut deadline: impl FnMut() -> bool, mut deadline: impl FnMut() -> bool,
) -> Vec<Mutations<'a>> { ) -> Vec<Mutations<'a>> {
/*
Strategy:
- When called, check for any UI events that might've been received since the last frame.
- Dump all UI events into a "pending discrete" queue and a "pending continuous" queue.
- If there are any pending discrete events, then elevate our priority level. If our priority level is already "high,"
then we need to finish the high priority work first. If the current work is "low" then analyze what scopes
will be invalidated by this new work. If this interferes with any in-flight medium or low work, then we need
to bump the other work out of the way, or choose to process it so we don't have any conflicts.
'static components have a leg up here since their work can be re-used among multiple scopes.
"High priority" is only for blocking! Should only be used on "clicks"
- If there are no pending discrete events, then check for continuous events. These can be completely batched
- we batch completely until we run into a discrete event
- all continuous events are batched together
- so D C C C C C would be two separate events - D and C. IE onclick and onscroll
- D C C C C C C D C C C D would be D C D C D in 5 distinct phases.
- !listener bubbling is not currently implemented properly and will need to be implemented somehow in the future
- we need to keep track of element parents to be able to traverse properly
Open questions:
- what if we get two clicks from the component during the same slice?
- should we batch?
- react says no - they are continuous
- but if we received both - then we don't need to diff, do we? run as many as we can and then finally diff?
*/
let mut committed_mutations = Vec::<Mutations<'static>>::new(); let mut committed_mutations = Vec::<Mutations<'static>>::new();
while self.has_any_work() { while self.has_any_work() {
while let Ok(Some(msg)) = self.receiver.try_next() { while let Ok(Some(msg)) = self.receiver.try_next() {
match msg { self.pending_messages.push_front(msg);
SchedulerMsg::Immediate(im) => {
self.dirty_scopes.insert(im);
}
SchedulerMsg::UiEvent(evt) => {
self.ui_events.push_back(evt);
}
}
} }
// switch our priority, pop off any work for msg in self.pending_messages.drain(..) {
while let Some(event) = self.ui_events.pop_front() { match msg {
if let Some(scope) = self.get_scope_mut(&event.scope) { SchedulerMsg::Immediate(id) => {
if let Some(element) = event.mounted_dom_id { // it's dirty
log::info!("Calling listener {:?}, {:?}", event.scope, element); self.dirty_scopes.insert(id);
}
SchedulerMsg::UiEvent(event) => {
// there's an event
let scope = self.scopes.get(&event.scope_id).unwrap();
if let Some(element) = event.mounted_dom_id {
log::info!("Calling listener {:?}, {:?}", event.scope_id, element);
// TODO: bubble properly here // TODO: bubble properly here
scope.call_listener(event, element); scope.call_listener(event, element);
while let Ok(Some(dirty_scope)) = self.receiver.try_next() { while let Ok(Some(dirty_scope)) = self.receiver.try_next() {
match dirty_scope { match dirty_scope {
SchedulerMsg::Immediate(im) => { SchedulerMsg::Immediate(im) => {
self.dirty_scopes.insert(im); self.dirty_scopes.insert(im);
}
SchedulerMsg::UiEvent(e) => self.ui_events.push_back(e),
} }
SchedulerMsg::UiEvent(e) => self.ui_events.push_back(e),
} }
} }
} }
} }
} }
let work_complete = self.work_on_current_lane(&mut deadline, &mut committed_mutations); let work_complete = {
// Work through the current subtree, and commit the results when it finishes
// When the deadline expires, give back the work
let saved_state = unsafe { self.load_work() };
// We have to split away some parts of ourself - current lane is borrowed mutably
let mut machine = unsafe { saved_state.promote() };
let mut ran_scopes = FxHashSet::default();
if machine.stack.is_empty() {
todo!("order scopes");
// self.dirty_scopes.retain(|id| self.get_scope(id).is_some());
// self.dirty_scopes.sort_by(|a, b| {
// let h1 = self.get_scope(a).unwrap().height;
// let h2 = self.get_scope(b).unwrap().height;
// h1.cmp(&h2).reverse()
// });
if let Some(scopeid) = self.dirty_scopes.pop() {
log::info!("handling dirty scope {:?}", scopeid);
if !ran_scopes.contains(&scopeid) {
ran_scopes.insert(scopeid);
log::debug!("about to run scope {:?}", scopeid);
// if let Some(component) = self.get_scope_mut(&scopeid) {
if self.run_scope(&scopeid) {
todo!("diff the scope")
// let (old, new) = (component.frames.wip_head(), component.frames.fin_head());
// // let (old, new) = (component.frames.wip_head(), component.frames.fin_head());
// machine.stack.scope_stack.push(scopeid);
// machine.stack.push(DiffInstruction::Diff { new, old });
}
// }
}
}
}
let work_completed: bool = todo!();
// let work_completed = machine.work(deadline_reached);
// log::debug!("raw edits {:?}", machine.mutations.edits);
let mut machine: DiffState<'static> = unsafe { std::mem::transmute(machine) };
// let mut saved = machine.save();
if work_completed {
for node in machine.seen_scopes.drain() {
// self.dirty_scopes.clear();
// self.ui_events.clear();
self.dirty_scopes.remove(&node);
// self.dirty_scopes.remove(&node);
}
let mut new_mutations = Mutations::new();
for edit in machine.mutations.edits.drain(..) {
new_mutations.edits.push(edit);
}
// for edit in saved.edits.drain(..) {
// new_mutations.edits.push(edit);
// }
// std::mem::swap(&mut new_mutations, &mut saved.mutations);
mutations.push(new_mutations);
// log::debug!("saved edits {:?}", mutations);
todo!();
// let mut saved = machine.save();
// self.save_work(saved);
true
// self.save_work(saved);
// false
} else {
false
}
};
if !work_complete { if !work_complete {
return committed_mutations; return committed_mutations;
@@ -446,193 +476,26 @@ impl VirtualDom {
committed_mutations committed_mutations
} }
}
pub enum SchedulerMsg { /// Performs a *full* rebuild of the virtual dom, returning every edit required to generate the actual dom from scratch
// events from the host
UiEvent(UserEvent),
// setstate
Immediate(ScopeId),
}
#[derive(Debug)]
pub struct UserEvent {
/// The originator of the event trigger
pub scope: ScopeId,
/// The optional real node associated with the trigger
pub mounted_dom_id: Option<ElementId>,
/// The event type IE "onclick" or "onmouseover"
/// ///
/// The name that the renderer will use to mount the listener. /// The diff machine expects the RealDom's stack to be the root of the application.
pub name: &'static str,
/// The type of event
pub event: Box<dyn Any + Send>,
}
/// Priority of Event Triggers.
///
/// Internally, Dioxus will abort work that's taking too long if new, more important work arrives. Unlike React, Dioxus
/// won't be afraid to pause work or flush changes to the RealDOM. This is called "cooperative scheduling". Some Renderers
/// implement this form of scheduling internally, however Dioxus will perform its own scheduling as well.
///
/// The ultimate goal of the scheduler is to manage latency of changes, prioritizing "flashier" changes over "subtler" changes.
///
/// React has a 5-tier priority system. However, they break things into "Continuous" and "Discrete" priority. For now,
/// we keep it simple, and just use a 3-tier priority system.
///
/// - NoPriority = 0
/// - LowPriority = 1
/// - NormalPriority = 2
/// - UserBlocking = 3
/// - HighPriority = 4
/// - ImmediatePriority = 5
///
/// We still have a concept of discrete vs continuous though - discrete events won't be batched, but continuous events will.
/// This means that multiple "scroll" events will be processed in a single frame, but multiple "click" events will be
/// flushed before proceeding. Multiple discrete events is highly unlikely, though.
#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, PartialOrd, Ord)]
pub enum EventPriority {
/// Work that must be completed during the EventHandler phase.
/// ///
/// Currently this is reserved for controlled inputs. /// Tasks will not be polled with this method, nor will any events be processed from the event queue. Instead, the
Immediate = 3, /// root component will be ran once and then diffed. All updates will flow out as mutations.
/// "High Priority" work will not interrupt other high priority work, but will interrupt medium and low priority work.
/// ///
/// This is typically reserved for things like user interaction. /// All state stored in components will be completely wiped away.
/// ///
/// React calls these "discrete" events, but with an extra category of "user-blocking" (Immediate). /// # Example
High = 2, /// ```
/// static App: FC<()> = |(cx, props)| cx.render(rsx!{ "hello world" });
/// "Medium priority" work is generated by page events not triggered by the user. These types of events are less important /// let mut dom = VirtualDom::new();
/// than "High Priority" events and will take precedence over low priority events. /// let edits = dom.rebuild();
/// ///
/// This is typically reserved for VirtualEvents that are not related to keyboard or mouse input. /// apply_edits(edits);
/// /// ```
/// React calls these "continuous" events (e.g. mouse move, mouse wheel, touch move, etc). pub fn rebuild(&mut self) -> Mutations {
Medium = 1, self.hard_diff(&self.base_scope)
/// "Low Priority" work will always be preempted unless the work is significantly delayed, in which case it will be
/// advanced to the front of the work queue until completed.
///
/// The primary user of Low Priority work is the asynchronous work system (Suspense).
///
/// This is considered "idle" work or "background" work.
Low = 0,
}
/// The scheduler holds basically everything around "working"
///
/// Each scope has the ability to lightly interact with the scheduler (IE, schedule an update) but ultimately the scheduler calls the components.
///
/// In Dioxus, the scheduler provides 4 priority levels - each with their own "DiffMachine". The DiffMachine state can be saved if the deadline runs
/// out.
///
/// Saved DiffMachine state can be self-referential, so we need to be careful about how we save it. All self-referential data is a link between
/// pending DiffInstructions, Mutations, and their underlying Scope. It's okay for us to be self-referential with this data, provided we don't priority
/// task shift to a higher priority task that needs mutable access to the same scopes.
///
/// We can prevent this safety issue from occurring if we track which scopes are invalidated when starting a new task.
///
/// There's a lot of raw pointers here...
///
/// Since we're building self-referential structures for each component, we need to make sure that the referencs stay stable
/// The best way to do that is a bump allocator.
///
///
///
impl VirtualDom {
/// Load the current lane, and work on it, periodically checking in if the deadline has been reached.
///
/// Returns true if the lane is finished before the deadline could be met.
pub fn work_on_current_lane(
&mut self,
deadline_reached: impl FnMut() -> bool,
mutations: &mut Vec<Mutations>,
) -> bool {
// Work through the current subtree, and commit the results when it finishes
// When the deadline expires, give back the work
let saved_state = unsafe { self.load_work() };
// We have to split away some parts of ourself - current lane is borrowed mutably
let mut machine = unsafe { saved_state.promote() };
let mut ran_scopes = FxHashSet::default();
if machine.stack.is_empty() {
todo!("order scopes");
// self.dirty_scopes.retain(|id| self.get_scope(id).is_some());
// self.dirty_scopes.sort_by(|a, b| {
// let h1 = self.get_scope(a).unwrap().height;
// let h2 = self.get_scope(b).unwrap().height;
// h1.cmp(&h2).reverse()
// });
if let Some(scopeid) = self.dirty_scopes.pop() {
log::info!("handling dirty scope {:?}", scopeid);
if !ran_scopes.contains(&scopeid) {
ran_scopes.insert(scopeid);
log::debug!("about to run scope {:?}", scopeid);
// if let Some(component) = self.get_scope_mut(&scopeid) {
if self.run_scope(&scopeid) {
todo!("diff the scope")
// let (old, new) = (component.frames.wip_head(), component.frames.fin_head());
// // let (old, new) = (component.frames.wip_head(), component.frames.fin_head());
// machine.stack.scope_stack.push(scopeid);
// machine.stack.push(DiffInstruction::Diff { new, old });
}
// }
}
}
}
let work_completed: bool = todo!();
// let work_completed = machine.work(deadline_reached);
// log::debug!("raw edits {:?}", machine.mutations.edits);
let mut machine: DiffState<'static> = unsafe { std::mem::transmute(machine) };
// let mut saved = machine.save();
if work_completed {
for node in machine.seen_scopes.drain() {
// self.dirty_scopes.clear();
// self.ui_events.clear();
self.dirty_scopes.remove(&node);
// self.dirty_scopes.remove(&node);
}
let mut new_mutations = Mutations::new();
for edit in machine.mutations.edits.drain(..) {
new_mutations.edits.push(edit);
}
// for edit in saved.edits.drain(..) {
// new_mutations.edits.push(edit);
// }
// std::mem::swap(&mut new_mutations, &mut saved.mutations);
mutations.push(new_mutations);
// log::debug!("saved edits {:?}", mutations);
todo!();
// let mut saved = machine.save();
// self.save_work(saved);
true
// self.save_work(saved);
// false
} else {
false
}
} }
/// Compute a manual diff of the VirtualDOM between states. /// Compute a manual diff of the VirtualDOM between states.
@@ -787,3 +650,82 @@ impl VirtualDom {
todo!() todo!()
} }
} }
pub enum SchedulerMsg {
// events from the host
UiEvent(UserEvent),
// setstate
Immediate(ScopeId),
}
#[derive(Debug)]
pub struct UserEvent {
/// The originator of the event trigger
pub scope_id: ScopeId,
pub priority: EventPriority,
/// The optional real node associated with the trigger
pub mounted_dom_id: Option<ElementId>,
/// The event type IE "onclick" or "onmouseover"
///
/// The name that the renderer will use to mount the listener.
pub name: &'static str,
/// The type of event
pub event: Box<dyn Any + Send>,
}
/// Priority of Event Triggers.
///
/// Internally, Dioxus will abort work that's taking too long if new, more important work arrives. Unlike React, Dioxus
/// won't be afraid to pause work or flush changes to the RealDOM. This is called "cooperative scheduling". Some Renderers
/// implement this form of scheduling internally, however Dioxus will perform its own scheduling as well.
///
/// The ultimate goal of the scheduler is to manage latency of changes, prioritizing "flashier" changes over "subtler" changes.
///
/// React has a 5-tier priority system. However, they break things into "Continuous" and "Discrete" priority. For now,
/// we keep it simple, and just use a 3-tier priority system.
///
/// - NoPriority = 0
/// - LowPriority = 1
/// - NormalPriority = 2
/// - UserBlocking = 3
/// - HighPriority = 4
/// - ImmediatePriority = 5
///
/// We still have a concept of discrete vs continuous though - discrete events won't be batched, but continuous events will.
/// This means that multiple "scroll" events will be processed in a single frame, but multiple "click" events will be
/// flushed before proceeding. Multiple discrete events is highly unlikely, though.
#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, PartialOrd, Ord)]
pub enum EventPriority {
/// Work that must be completed during the EventHandler phase.
///
/// Currently this is reserved for controlled inputs.
Immediate = 3,
/// "High Priority" work will not interrupt other high priority work, but will interrupt medium and low priority work.
///
/// This is typically reserved for things like user interaction.
///
/// React calls these "discrete" events, but with an extra category of "user-blocking" (Immediate).
High = 2,
/// "Medium priority" work is generated by page events not triggered by the user. These types of events are less important
/// than "High Priority" events and will take precedence over low priority events.
///
/// This is typically reserved for VirtualEvents that are not related to keyboard or mouse input.
///
/// React calls these "continuous" events (e.g. mouse move, mouse wheel, touch move, etc).
Medium = 1,
/// "Low Priority" work will always be preempted unless the work is significantly delayed, in which case it will be
/// advanced to the front of the work queue until completed.
///
/// The primary user of Low Priority work is the asynchronous work system (Suspense).
///
/// This is considered "idle" work or "background" work.
Low = 0,
}
packages/desktop/src/events.rs
+4 -3
View File
@@ -24,7 +24,7 @@ pub fn trigger_from_serialized(val: serde_json::Value) -> UserEvent {
contents, contents,
} = ims.into_iter().next().unwrap(); } = ims.into_iter().next().unwrap();
let scope = ScopeId(scope as usize); let scope_id = ScopeId(scope as usize);
let mounted_dom_id = Some(ElementId(mounted_dom_id as usize)); let mounted_dom_id = Some(ElementId(mounted_dom_id as usize));
let name = event_name_from_typ(&event); let name = event_name_from_typ(&event);
@@ -32,9 +32,10 @@ pub fn trigger_from_serialized(val: serde_json::Value) -> UserEvent {
UserEvent { UserEvent {
name, name,
event, priority: EventPriority::Low,
scope, scope_id,
mounted_dom_id, mounted_dom_id,
event,
} }
} }