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use std::cell::Cell;
use std::collections::{HashMap, HashSet, VecDeque};
use std::default::Default;
use crossbeam_channel::{self, Receiver, Sender};
use msg::constellation_msg::PipelineId;
use crate::dom::bindings::cell::DomRefCell;
use crate::dom::worker::TrustedWorkerAddress;
use crate::script_runtime::ScriptThreadEventCategory;
use crate::script_thread::ScriptThread;
use crate::task::TaskBox;
use crate::task_source::TaskSourceName;
pub type QueuedTask = (
Option<TrustedWorkerAddress>,
ScriptThreadEventCategory,
Box<dyn TaskBox>,
Option<PipelineId>,
TaskSourceName,
);
pub trait QueuedTaskConversion {
fn task_source_name(&self) -> Option<&TaskSourceName>;
fn pipeline_id(&self) -> Option<PipelineId>;
fn into_queued_task(self) -> Option<QueuedTask>;
fn from_queued_task(queued_task: QueuedTask) -> Self;
fn inactive_msg() -> Self;
fn wake_up_msg() -> Self;
fn is_wake_up(&self) -> bool;
}
pub struct TaskQueue<T> {
port: Receiver<T>,
wake_up_sender: Sender<T>,
msg_queue: DomRefCell<VecDeque<T>>,
taken_task_counter: Cell<u64>,
throttled: DomRefCell<HashMap<TaskSourceName, VecDeque<QueuedTask>>>,
inactive: DomRefCell<HashMap<PipelineId, VecDeque<QueuedTask>>>,
}
impl<T: QueuedTaskConversion> TaskQueue<T> {
pub fn new(port: Receiver<T>, wake_up_sender: Sender<T>) -> TaskQueue<T> {
TaskQueue {
port,
wake_up_sender,
msg_queue: DomRefCell::new(VecDeque::new()),
taken_task_counter: Default::default(),
throttled: Default::default(),
inactive: Default::default(),
}
}
fn release_tasks_for_fully_active_documents(
&self,
fully_active: &HashSet<PipelineId>,
) -> Vec<T> {
self.inactive
.borrow_mut()
.iter_mut()
.filter(|(pipeline_id, _)| fully_active.contains(pipeline_id))
.flat_map(|(_, inactive_queue)| {
inactive_queue
.drain(0..)
.map(|queued_task| T::from_queued_task(queued_task))
})
.collect()
}
fn store_task_for_inactive_pipeline(&self, msg: T, pipeline_id: &PipelineId) {
let mut inactive = self.inactive.borrow_mut();
let inactive_queue = inactive.entry(pipeline_id.clone()).or_default();
inactive_queue.push_back(
msg.into_queued_task()
.expect("Incoming messages should always be convertible into queued tasks"),
);
let mut msg_queue = self.msg_queue.borrow_mut();
if msg_queue.is_empty() {
msg_queue.push_back(T::inactive_msg());
}
}
fn process_incoming_tasks(&self, first_msg: T, fully_active: &HashSet<PipelineId>) {
let mut incoming = self.release_tasks_for_fully_active_documents(fully_active);
if !first_msg.is_wake_up() {
incoming.push(first_msg);
}
while let Ok(msg) = self.port.try_recv() {
if !msg.is_wake_up() {
incoming.push(msg);
}
}
let mut to_be_throttled = Vec::new();
let mut index = 0;
while index != incoming.len() {
index += 1; let task_source = match incoming[index - 1].task_source_name() {
Some(task_source) => task_source,
None => continue,
};
match task_source {
TaskSourceName::PerformanceTimeline => {
to_be_throttled.push(incoming.remove(index - 1));
index -= 1; },
_ => {
self.taken_task_counter
.set(self.taken_task_counter.get() + 1);
},
}
}
for msg in incoming {
if let Some(pipeline_id) = msg.pipeline_id() {
if !fully_active.contains(&pipeline_id) {
self.store_task_for_inactive_pipeline(msg, &pipeline_id);
continue;
}
}
let _ = self.msg_queue.borrow_mut().push_back(msg);
}
for msg in to_be_throttled {
let (worker, category, boxed, pipeline_id, task_source) = match msg.into_queued_task() {
Some(queued_task) => queued_task,
None => unreachable!(
"A message to be throttled should always be convertible into a queued task"
),
};
let mut throttled_tasks = self.throttled.borrow_mut();
throttled_tasks
.entry(task_source.clone())
.or_default()
.push_back((worker, category, boxed, pipeline_id, task_source));
}
}
pub fn select(&self) -> &crossbeam_channel::Receiver<T> {
self.taken_task_counter.set(0);
&self.port
}
pub fn recv(&self) -> Result<T, ()> {
self.msg_queue.borrow_mut().pop_front().ok_or(())
}
pub fn try_recv(&self) -> Result<T, ()> {
self.recv()
}
pub fn take_tasks(&self, first_msg: T) {
const PER_ITERATION_MAX: u64 = 5;
let fully_active = ScriptThread::get_fully_active_document_ids();
self.process_incoming_tasks(first_msg, &fully_active);
let mut throttled = self.throttled.borrow_mut();
let mut throttled_length: usize = throttled.values().map(|queue| queue.len()).sum();
let task_source_names = TaskSourceName::all();
let mut task_source_cycler = task_source_names.iter().cycle();
loop {
let max_reached = self.taken_task_counter.get() > PER_ITERATION_MAX;
let none_left = throttled_length == 0;
match (max_reached, none_left) {
(_, true) => break,
(true, false) => {
let _ = self.wake_up_sender.send(T::wake_up_msg());
break;
},
(false, false) => {
let task_source = task_source_cycler.next().unwrap();
let throttled_queue = match throttled.get_mut(&task_source) {
Some(queue) => queue,
None => continue,
};
let queued_task = match throttled_queue.pop_front() {
Some(queued_task) => queued_task,
None => continue,
};
let msg = T::from_queued_task(queued_task);
if let Some(pipeline_id) = msg.pipeline_id() {
if !fully_active.contains(&pipeline_id) {
self.store_task_for_inactive_pipeline(msg, &pipeline_id);
throttled_length = throttled_length - 1;
continue;
}
}
let _ = self.msg_queue.borrow_mut().push_back(msg);
self.taken_task_counter
.set(self.taken_task_counter.get() + 1);
throttled_length = throttled_length - 1;
},
}
}
}
}