1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786
use std::{
any::Any,
sync::{Arc, Mutex, MutexGuard},
};
use bevy_tasks::{ComputeTaskPool, Scope, TaskPool, ThreadExecutor};
use bevy_utils::default;
use bevy_utils::syncunsafecell::SyncUnsafeCell;
#[cfg(feature = "trace")]
use bevy_utils::tracing::{info_span, Span};
use std::panic::AssertUnwindSafe;
use concurrent_queue::ConcurrentQueue;
use fixedbitset::FixedBitSet;
use crate::{
archetype::ArchetypeComponentId,
prelude::Resource,
query::Access,
schedule::{is_apply_deferred, BoxedCondition, ExecutorKind, SystemExecutor, SystemSchedule},
system::BoxedSystem,
world::{unsafe_world_cell::UnsafeWorldCell, World},
};
use crate as bevy_ecs;
use super::__rust_begin_short_backtrace;
/// Borrowed data used by the [`MultiThreadedExecutor`].
struct Environment<'env, 'sys> {
executor: &'env MultiThreadedExecutor,
systems: &'sys [SyncUnsafeCell<BoxedSystem>],
conditions: SyncUnsafeCell<Conditions<'sys>>,
world_cell: UnsafeWorldCell<'env>,
}
struct Conditions<'a> {
system_conditions: &'a mut [Vec<BoxedCondition>],
set_conditions: &'a mut [Vec<BoxedCondition>],
sets_with_conditions_of_systems: &'a [FixedBitSet],
systems_in_sets_with_conditions: &'a [FixedBitSet],
}
impl<'env, 'sys> Environment<'env, 'sys> {
fn new(
executor: &'env MultiThreadedExecutor,
schedule: &'sys mut SystemSchedule,
world: &'env mut World,
) -> Self {
Environment {
executor,
systems: SyncUnsafeCell::from_mut(schedule.systems.as_mut_slice()).as_slice_of_cells(),
conditions: SyncUnsafeCell::new(Conditions {
system_conditions: &mut schedule.system_conditions,
set_conditions: &mut schedule.set_conditions,
sets_with_conditions_of_systems: &schedule.sets_with_conditions_of_systems,
systems_in_sets_with_conditions: &schedule.systems_in_sets_with_conditions,
}),
world_cell: world.as_unsafe_world_cell(),
}
}
}
/// Per-system data used by the [`MultiThreadedExecutor`].
// Copied here because it can't be read from the system when it's running.
struct SystemTaskMetadata {
/// The [`ArchetypeComponentId`] access of the system.
archetype_component_access: Access<ArchetypeComponentId>,
/// Indices of the systems that directly depend on the system.
dependents: Vec<usize>,
/// Is `true` if the system does not access `!Send` data.
is_send: bool,
/// Is `true` if the system is exclusive.
is_exclusive: bool,
}
/// The result of running a system that is sent across a channel.
struct SystemResult {
system_index: usize,
}
/// Runs the schedule using a thread pool. Non-conflicting systems can run in parallel.
pub struct MultiThreadedExecutor {
/// The running state, protected by a mutex so that a reference to the executor can be shared across tasks.
state: Mutex<ExecutorState>,
/// Queue of system completion events.
system_completion: ConcurrentQueue<SystemResult>,
/// Setting when true applies deferred system buffers after all systems have run
apply_final_deferred: bool,
/// When set, tells the executor that a thread has panicked.
panic_payload: Mutex<Option<Box<dyn Any + Send>>>,
starting_systems: FixedBitSet,
/// Cached tracing span
#[cfg(feature = "trace")]
executor_span: Span,
}
/// The state of the executor while running.
pub struct ExecutorState {
/// Metadata for scheduling and running system tasks.
system_task_metadata: Vec<SystemTaskMetadata>,
/// Union of the accesses of all currently running systems.
active_access: Access<ArchetypeComponentId>,
/// Returns `true` if a system with non-`Send` access is running.
local_thread_running: bool,
/// Returns `true` if an exclusive system is running.
exclusive_running: bool,
/// The number of systems that are running.
num_running_systems: usize,
/// The number of dependencies each system has that have not completed.
num_dependencies_remaining: Vec<usize>,
/// System sets whose conditions have been evaluated.
evaluated_sets: FixedBitSet,
/// Systems that have no remaining dependencies and are waiting to run.
ready_systems: FixedBitSet,
/// copy of `ready_systems`
ready_systems_copy: FixedBitSet,
/// Systems that are running.
running_systems: FixedBitSet,
/// Systems that got skipped.
skipped_systems: FixedBitSet,
/// Systems whose conditions have been evaluated and were run or skipped.
completed_systems: FixedBitSet,
/// Systems that have run but have not had their buffers applied.
unapplied_systems: FixedBitSet,
}
/// References to data required by the executor.
/// This is copied to each system task so that can invoke the executor when they complete.
// These all need to outlive 'scope in order to be sent to new tasks,
// and keeping them all in a struct means we can use lifetime elision.
#[derive(Copy, Clone)]
struct Context<'scope, 'env, 'sys> {
environment: &'env Environment<'env, 'sys>,
scope: &'scope Scope<'scope, 'env, ()>,
}
impl Default for MultiThreadedExecutor {
fn default() -> Self {
Self::new()
}
}
impl SystemExecutor for MultiThreadedExecutor {
fn kind(&self) -> ExecutorKind {
ExecutorKind::MultiThreaded
}
fn init(&mut self, schedule: &SystemSchedule) {
let state = self.state.get_mut().unwrap();
// pre-allocate space
let sys_count = schedule.system_ids.len();
let set_count = schedule.set_ids.len();
self.system_completion = ConcurrentQueue::bounded(sys_count.max(1));
self.starting_systems = FixedBitSet::with_capacity(sys_count);
state.evaluated_sets = FixedBitSet::with_capacity(set_count);
state.ready_systems = FixedBitSet::with_capacity(sys_count);
state.ready_systems_copy = FixedBitSet::with_capacity(sys_count);
state.running_systems = FixedBitSet::with_capacity(sys_count);
state.completed_systems = FixedBitSet::with_capacity(sys_count);
state.skipped_systems = FixedBitSet::with_capacity(sys_count);
state.unapplied_systems = FixedBitSet::with_capacity(sys_count);
state.system_task_metadata = Vec::with_capacity(sys_count);
for index in 0..sys_count {
state.system_task_metadata.push(SystemTaskMetadata {
archetype_component_access: default(),
dependents: schedule.system_dependents[index].clone(),
is_send: schedule.systems[index].is_send(),
is_exclusive: schedule.systems[index].is_exclusive(),
});
if schedule.system_dependencies[index] == 0 {
self.starting_systems.insert(index);
}
}
state.num_dependencies_remaining = Vec::with_capacity(sys_count);
}
fn run(
&mut self,
schedule: &mut SystemSchedule,
world: &mut World,
_skip_systems: Option<&FixedBitSet>,
) {
let state = self.state.get_mut().unwrap();
// reset counts
if schedule.systems.is_empty() {
return;
}
state.num_running_systems = 0;
state
.num_dependencies_remaining
.clone_from(&schedule.system_dependencies);
state.ready_systems.clone_from(&self.starting_systems);
// If stepping is enabled, make sure we skip those systems that should
// not be run.
#[cfg(feature = "bevy_debug_stepping")]
if let Some(skipped_systems) = _skip_systems {
debug_assert_eq!(skipped_systems.len(), state.completed_systems.len());
// mark skipped systems as completed
state.completed_systems |= skipped_systems;
// signal the dependencies for each of the skipped systems, as
// though they had run
for system_index in skipped_systems.ones() {
state.signal_dependents(system_index);
state.ready_systems.remove(system_index);
}
}
let thread_executor = world
.get_resource::<MainThreadExecutor>()
.map(|e| e.0.clone());
let thread_executor = thread_executor.as_deref();
let environment = &Environment::new(self, schedule, world);
ComputeTaskPool::get_or_init(TaskPool::default).scope_with_executor(
false,
thread_executor,
|scope| {
let context = Context { environment, scope };
// The first tick won't need to process finished systems, but we still need to run the loop in
// tick_executor() in case a system completes while the first tick still holds the mutex.
context.tick_executor();
},
);
// End the borrows of self and world in environment by copying out the reference to systems.
let systems = environment.systems;
let state = self.state.get_mut().unwrap();
if self.apply_final_deferred {
// Do one final apply buffers after all systems have completed
// Commands should be applied while on the scope's thread, not the executor's thread
let res = apply_deferred(&state.unapplied_systems, systems, world);
if let Err(payload) = res {
let panic_payload = self.panic_payload.get_mut().unwrap();
*panic_payload = Some(payload);
}
state.unapplied_systems.clear();
}
// check to see if there was a panic
let payload = self.panic_payload.get_mut().unwrap();
if let Some(payload) = payload.take() {
std::panic::resume_unwind(payload);
}
debug_assert!(state.ready_systems.is_clear());
debug_assert!(state.running_systems.is_clear());
state.active_access.clear();
state.evaluated_sets.clear();
state.skipped_systems.clear();
state.completed_systems.clear();
}
fn set_apply_final_deferred(&mut self, value: bool) {
self.apply_final_deferred = value;
}
}
impl<'scope, 'env: 'scope, 'sys> Context<'scope, 'env, 'sys> {
fn system_completed(
&self,
system_index: usize,
res: Result<(), Box<dyn Any + Send>>,
system: &BoxedSystem,
) {
// tell the executor that the system finished
self.environment
.executor
.system_completion
.push(SystemResult { system_index })
.unwrap_or_else(|error| unreachable!("{}", error));
if let Err(payload) = res {
eprintln!("Encountered a panic in system `{}`!", &*system.name());
// set the payload to propagate the error
{
let mut panic_payload = self.environment.executor.panic_payload.lock().unwrap();
*panic_payload = Some(payload);
}
}
self.tick_executor();
}
fn try_lock<'a>(&'a self) -> Option<(&'a mut Conditions<'sys>, MutexGuard<'a, ExecutorState>)> {
let guard = self.environment.executor.state.try_lock().ok()?;
// SAFETY: This is an exclusive access as no other location fetches conditions mutably, and
// is synchronized by the lock on the executor state.
let conditions = unsafe { &mut *self.environment.conditions.get() };
Some((conditions, guard))
}
fn tick_executor(&self) {
// Ensure that the executor handles any events pushed to the system_completion queue by this thread.
// If this thread acquires the lock, the exector runs after the push() and they are processed.
// If this thread does not acquire the lock, then the is_empty() check on the other thread runs
// after the lock is released, which is after try_lock() failed, which is after the push()
// on this thread, so the is_empty() check will see the new events and loop.
loop {
let Some((conditions, mut guard)) = self.try_lock() else {
return;
};
guard.tick(self, conditions);
// Make sure we drop the guard before checking system_completion.is_empty(), or we could lose events.
drop(guard);
if self.environment.executor.system_completion.is_empty() {
return;
}
}
}
}
impl MultiThreadedExecutor {
/// Creates a new `multi_threaded` executor for use with a [`Schedule`].
///
/// [`Schedule`]: crate::schedule::Schedule
pub fn new() -> Self {
Self {
state: Mutex::new(ExecutorState::new()),
system_completion: ConcurrentQueue::unbounded(),
starting_systems: FixedBitSet::new(),
apply_final_deferred: true,
panic_payload: Mutex::new(None),
#[cfg(feature = "trace")]
executor_span: info_span!("multithreaded executor"),
}
}
}
impl ExecutorState {
fn new() -> Self {
Self {
system_task_metadata: Vec::new(),
num_running_systems: 0,
num_dependencies_remaining: Vec::new(),
active_access: default(),
local_thread_running: false,
exclusive_running: false,
evaluated_sets: FixedBitSet::new(),
ready_systems: FixedBitSet::new(),
ready_systems_copy: FixedBitSet::new(),
running_systems: FixedBitSet::new(),
skipped_systems: FixedBitSet::new(),
completed_systems: FixedBitSet::new(),
unapplied_systems: FixedBitSet::new(),
}
}
fn tick(&mut self, context: &Context, conditions: &mut Conditions) {
#[cfg(feature = "trace")]
let _span = context.environment.executor.executor_span.enter();
for result in context.environment.executor.system_completion.try_iter() {
self.finish_system_and_handle_dependents(result);
}
self.rebuild_active_access();
// SAFETY:
// - `finish_system_and_handle_dependents` has updated the currently running systems.
// - `rebuild_active_access` locks access for all currently running systems.
unsafe {
self.spawn_system_tasks(context, conditions);
}
}
/// # Safety
/// - Caller must ensure that `self.ready_systems` does not contain any systems that
/// have been mutably borrowed (such as the systems currently running).
/// - `world_cell` must have permission to access all world data (not counting
/// any world data that is claimed by systems currently running on this executor).
unsafe fn spawn_system_tasks(&mut self, context: &Context, conditions: &mut Conditions) {
if self.exclusive_running {
return;
}
// can't borrow since loop mutably borrows `self`
let mut ready_systems = std::mem::take(&mut self.ready_systems_copy);
// Skipping systems may cause their dependents to become ready immediately.
// If that happens, we need to run again immediately or we may fail to spawn those dependents.
let mut check_for_new_ready_systems = true;
while check_for_new_ready_systems {
check_for_new_ready_systems = false;
ready_systems.clone_from(&self.ready_systems);
for system_index in ready_systems.ones() {
debug_assert!(!self.running_systems.contains(system_index));
// SAFETY: Caller assured that these systems are not running.
// Therefore, no other reference to this system exists and there is no aliasing.
let system = unsafe { &mut *context.environment.systems[system_index].get() };
if !self.can_run(
system_index,
system,
conditions,
context.environment.world_cell,
) {
// NOTE: exclusive systems with ambiguities are susceptible to
// being significantly displaced here (compared to single-threaded order)
// if systems after them in topological order can run
// if that becomes an issue, `break;` if exclusive system
continue;
}
self.ready_systems.remove(system_index);
// SAFETY: `can_run` returned true, which means that:
// - It must have called `update_archetype_component_access` for each run condition.
// - There can be no systems running whose accesses would conflict with any conditions.
if unsafe {
!self.should_run(
system_index,
system,
conditions,
context.environment.world_cell,
)
} {
self.skip_system_and_signal_dependents(system_index);
// signal_dependents may have set more systems to ready.
check_for_new_ready_systems = true;
continue;
}
self.running_systems.insert(system_index);
self.num_running_systems += 1;
if self.system_task_metadata[system_index].is_exclusive {
// SAFETY: `can_run` returned true for this system,
// which means no systems are currently borrowed.
unsafe {
self.spawn_exclusive_system_task(context, system_index);
}
check_for_new_ready_systems = false;
break;
}
// SAFETY:
// - Caller ensured no other reference to this system exists.
// - `can_run` has been called, which calls `update_archetype_component_access` with this system.
// - `can_run` returned true, so no systems with conflicting world access are running.
unsafe {
self.spawn_system_task(context, system_index);
}
}
}
// give back
self.ready_systems_copy = ready_systems;
}
fn can_run(
&mut self,
system_index: usize,
system: &mut BoxedSystem,
conditions: &mut Conditions,
world: UnsafeWorldCell,
) -> bool {
let system_meta = &self.system_task_metadata[system_index];
if system_meta.is_exclusive && self.num_running_systems > 0 {
return false;
}
if !system_meta.is_send && self.local_thread_running {
return false;
}
// TODO: an earlier out if world's archetypes did not change
for set_idx in conditions.sets_with_conditions_of_systems[system_index]
.difference(&self.evaluated_sets)
{
for condition in &mut conditions.set_conditions[set_idx] {
condition.update_archetype_component_access(world);
if !condition
.archetype_component_access()
.is_compatible(&self.active_access)
{
return false;
}
}
}
for condition in &mut conditions.system_conditions[system_index] {
condition.update_archetype_component_access(world);
if !condition
.archetype_component_access()
.is_compatible(&self.active_access)
{
return false;
}
}
if !self.skipped_systems.contains(system_index) {
system.update_archetype_component_access(world);
if !system
.archetype_component_access()
.is_compatible(&self.active_access)
{
return false;
}
self.system_task_metadata[system_index]
.archetype_component_access
.clone_from(system.archetype_component_access());
}
true
}
/// # Safety
/// * `world` must have permission to read any world data required by
/// the system's conditions: this includes conditions for the system
/// itself, and conditions for any of the system's sets.
/// * `update_archetype_component` must have been called with `world`
/// for each run condition in `conditions`.
unsafe fn should_run(
&mut self,
system_index: usize,
_system: &BoxedSystem,
conditions: &mut Conditions,
world: UnsafeWorldCell,
) -> bool {
let mut should_run = !self.skipped_systems.contains(system_index);
for set_idx in conditions.sets_with_conditions_of_systems[system_index].ones() {
if self.evaluated_sets.contains(set_idx) {
continue;
}
// Evaluate the system set's conditions.
// SAFETY:
// - The caller ensures that `world` has permission to read any data
// required by the conditions.
// - `update_archetype_component_access` has been called for each run condition.
let set_conditions_met = unsafe {
evaluate_and_fold_conditions(&mut conditions.set_conditions[set_idx], world)
};
if !set_conditions_met {
self.skipped_systems
.union_with(&conditions.systems_in_sets_with_conditions[set_idx]);
}
should_run &= set_conditions_met;
self.evaluated_sets.insert(set_idx);
}
// Evaluate the system's conditions.
// SAFETY:
// - The caller ensures that `world` has permission to read any data
// required by the conditions.
// - `update_archetype_component_access` has been called for each run condition.
let system_conditions_met = unsafe {
evaluate_and_fold_conditions(&mut conditions.system_conditions[system_index], world)
};
if !system_conditions_met {
self.skipped_systems.insert(system_index);
}
should_run &= system_conditions_met;
should_run
}
/// # Safety
/// - Caller must not alias systems that are running.
/// - `world` must have permission to access the world data
/// used by the specified system.
/// - `update_archetype_component_access` must have been called with `world`
/// on the system associated with `system_index`.
unsafe fn spawn_system_task(&mut self, context: &Context, system_index: usize) {
// SAFETY: this system is not running, no other reference exists
let system = unsafe { &mut *context.environment.systems[system_index].get() };
// Move the full context object into the new future.
let context = *context;
let system_meta = &self.system_task_metadata[system_index];
let task = async move {
let res = std::panic::catch_unwind(AssertUnwindSafe(|| {
// SAFETY:
// - The caller ensures that we have permission to
// access the world data used by the system.
// - `update_archetype_component_access` has been called.
unsafe {
__rust_begin_short_backtrace::run_unsafe(
&mut **system,
context.environment.world_cell,
);
};
}));
context.system_completed(system_index, res, system);
};
self.active_access
.extend(&system_meta.archetype_component_access);
if system_meta.is_send {
context.scope.spawn(task);
} else {
self.local_thread_running = true;
context.scope.spawn_on_external(task);
}
}
/// # Safety
/// Caller must ensure no systems are currently borrowed.
unsafe fn spawn_exclusive_system_task(&mut self, context: &Context, system_index: usize) {
// SAFETY: `can_run` returned true for this system, which means
// that no other systems currently have access to the world.
let world = unsafe { context.environment.world_cell.world_mut() };
// SAFETY: this system is not running, no other reference exists
let system = unsafe { &mut *context.environment.systems[system_index].get() };
// Move the full context object into the new future.
let context = *context;
if is_apply_deferred(system) {
// TODO: avoid allocation
let unapplied_systems = self.unapplied_systems.clone();
self.unapplied_systems.clear();
let task = async move {
let res = apply_deferred(&unapplied_systems, context.environment.systems, world);
context.system_completed(system_index, res, system);
};
context.scope.spawn_on_scope(task);
} else {
let task = async move {
let res = std::panic::catch_unwind(AssertUnwindSafe(|| {
__rust_begin_short_backtrace::run(&mut **system, world);
}));
context.system_completed(system_index, res, system);
};
context.scope.spawn_on_scope(task);
}
self.exclusive_running = true;
self.local_thread_running = true;
}
fn finish_system_and_handle_dependents(&mut self, result: SystemResult) {
let SystemResult { system_index, .. } = result;
if self.system_task_metadata[system_index].is_exclusive {
self.exclusive_running = false;
}
if !self.system_task_metadata[system_index].is_send {
self.local_thread_running = false;
}
debug_assert!(self.num_running_systems >= 1);
self.num_running_systems -= 1;
self.running_systems.remove(system_index);
self.completed_systems.insert(system_index);
self.unapplied_systems.insert(system_index);
self.signal_dependents(system_index);
}
fn skip_system_and_signal_dependents(&mut self, system_index: usize) {
self.completed_systems.insert(system_index);
self.signal_dependents(system_index);
}
fn signal_dependents(&mut self, system_index: usize) {
for &dep_idx in &self.system_task_metadata[system_index].dependents {
let remaining = &mut self.num_dependencies_remaining[dep_idx];
debug_assert!(*remaining >= 1);
*remaining -= 1;
if *remaining == 0 && !self.completed_systems.contains(dep_idx) {
self.ready_systems.insert(dep_idx);
}
}
}
fn rebuild_active_access(&mut self) {
self.active_access.clear();
for index in self.running_systems.ones() {
let system_meta = &self.system_task_metadata[index];
self.active_access
.extend(&system_meta.archetype_component_access);
}
}
}
fn apply_deferred(
unapplied_systems: &FixedBitSet,
systems: &[SyncUnsafeCell<BoxedSystem>],
world: &mut World,
) -> Result<(), Box<dyn Any + Send>> {
for system_index in unapplied_systems.ones() {
// SAFETY: none of these systems are running, no other references exist
let system = unsafe { &mut *systems[system_index].get() };
let res = std::panic::catch_unwind(AssertUnwindSafe(|| {
system.apply_deferred(world);
}));
if let Err(payload) = res {
eprintln!(
"Encountered a panic when applying buffers for system `{}`!",
&*system.name()
);
return Err(payload);
}
}
Ok(())
}
/// # Safety
/// - `world` must have permission to read any world data
/// required by `conditions`.
/// - `update_archetype_component_access` must have been called
/// with `world` for each condition in `conditions`.
unsafe fn evaluate_and_fold_conditions(
conditions: &mut [BoxedCondition],
world: UnsafeWorldCell,
) -> bool {
// not short-circuiting is intentional
#[allow(clippy::unnecessary_fold)]
conditions
.iter_mut()
.map(|condition| {
// SAFETY: The caller ensures that `world` has permission to
// access any data required by the condition.
unsafe { __rust_begin_short_backtrace::readonly_run_unsafe(&mut **condition, world) }
})
.fold(true, |acc, res| acc && res)
}
/// New-typed [`ThreadExecutor`] [`Resource`] that is used to run systems on the main thread
#[derive(Resource, Clone)]
pub struct MainThreadExecutor(pub Arc<ThreadExecutor<'static>>);
impl Default for MainThreadExecutor {
fn default() -> Self {
Self::new()
}
}
impl MainThreadExecutor {
/// Creates a new executor that can be used to run systems on the main thread.
pub fn new() -> Self {
MainThreadExecutor(TaskPool::get_thread_executor())
}
}
#[cfg(test)]
mod tests {
use crate::{
self as bevy_ecs,
prelude::Resource,
schedule::{ExecutorKind, IntoSystemConfigs, Schedule},
system::Commands,
world::World,
};
#[derive(Resource)]
struct R;
#[test]
fn skipped_systems_notify_dependents() {
let mut world = World::new();
let mut schedule = Schedule::default();
schedule.set_executor_kind(ExecutorKind::MultiThreaded);
schedule.add_systems(
(
(|| {}).run_if(|| false),
// This system depends on a system that is always skipped.
|mut commands: Commands| {
commands.insert_resource(R);
},
)
.chain(),
);
schedule.run(&mut world);
assert!(world.get_resource::<R>().is_some());
}
}