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|
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! A very simple unsynchronized channel type for sending buffered data from
//! scheduler context to task context.
//!
//! XXX: This would be safer to use if split into two types like Port/Chan
use option::*;
use clone::Clone;
use super::rc::RC;
use rt::sched::{Scheduler, Coroutine};
use rt::{context, TaskContext, SchedulerContext};
use rt::local::Local;
use vec::OwnedVector;
use container::Container;
struct TubeState<T> {
blocked_task: Option<~Coroutine>,
buf: ~[T]
}
pub struct Tube<T> {
p: RC<TubeState<T>>
}
impl<T> Tube<T> {
pub fn new() -> Tube<T> {
Tube {
p: RC::new(TubeState {
blocked_task: None,
buf: ~[]
})
}
}
pub fn send(&mut self, val: T) {
rtdebug!("tube send");
assert!(context() == SchedulerContext);
unsafe {
let state = self.p.unsafe_borrow_mut();
(*state).buf.push(val);
if (*state).blocked_task.is_some() {
// There's a waiting task. Wake it up
rtdebug!("waking blocked tube");
let task = (*state).blocked_task.swap_unwrap();
let sched = Local::take::<Scheduler>();
sched.resume_task_immediately(task);
}
}
}
pub fn recv(&mut self) -> T {
assert!(context() == TaskContext);
unsafe {
let state = self.p.unsafe_borrow_mut();
if !(*state).buf.is_empty() {
return (*state).buf.shift();
} else {
// Block and wait for the next message
rtdebug!("blocking on tube recv");
assert!(self.p.refcount() > 1); // There better be somebody to wake us up
assert!((*state).blocked_task.is_none());
let sched = Local::take::<Scheduler>();
do sched.deschedule_running_task_and_then |task| {
(*state).blocked_task = Some(task);
}
rtdebug!("waking after tube recv");
let buf = &mut (*state).buf;
assert!(!buf.is_empty());
return buf.shift();
}
}
}
}
impl<T> Clone for Tube<T> {
fn clone(&self) -> Tube<T> {
Tube { p: self.p.clone() }
}
}
#[cfg(test)]
mod test {
use int;
use cell::Cell;
use rt::test::*;
use rt::rtio::EventLoop;
use rt::sched::Scheduler;
use rt::local::Local;
use super::*;
#[test]
fn simple_test() {
do run_in_newsched_task {
let mut tube: Tube<int> = Tube::new();
let tube_clone = tube.clone();
let tube_clone_cell = Cell::new(tube_clone);
let sched = Local::take::<Scheduler>();
do sched.deschedule_running_task_and_then |task| {
let mut tube_clone = tube_clone_cell.take();
tube_clone.send(1);
let sched = Local::take::<Scheduler>();
sched.resume_task_immediately(task);
}
assert!(tube.recv() == 1);
}
}
#[test]
fn blocking_test() {
do run_in_newsched_task {
let mut tube: Tube<int> = Tube::new();
let tube_clone = tube.clone();
let tube_clone = Cell::new(Cell::new(Cell::new(tube_clone)));
let sched = Local::take::<Scheduler>();
do sched.deschedule_running_task_and_then |task| {
let tube_clone = tube_clone.take();
do Local::borrow::<Scheduler> |sched| {
let tube_clone = tube_clone.take();
do sched.event_loop.callback {
let mut tube_clone = tube_clone.take();
// The task should be blocked on this now and
// sending will wake it up.
tube_clone.send(1);
}
}
let sched = Local::take::<Scheduler>();
sched.resume_task_immediately(task);
}
assert!(tube.recv() == 1);
}
}
#[test]
fn many_blocking_test() {
static MAX: int = 100;
do run_in_newsched_task {
let mut tube: Tube<int> = Tube::new();
let tube_clone = tube.clone();
let tube_clone = Cell::new(tube_clone);
let sched = Local::take::<Scheduler>();
do sched.deschedule_running_task_and_then |task| {
callback_send(tube_clone.take(), 0);
fn callback_send(tube: Tube<int>, i: int) {
if i == 100 { return; }
let tube = Cell::new(Cell::new(tube));
do Local::borrow::<Scheduler> |sched| {
let tube = tube.take();
do sched.event_loop.callback {
let mut tube = tube.take();
// The task should be blocked on this now and
// sending will wake it up.
tube.send(i);
callback_send(tube, i + 1);
}
}
}
let sched = Local::take::<Scheduler>();
sched.resume_task_immediately(task);
}
for int::range(0, MAX) |i| {
let j = tube.recv();
assert!(j == i);
}
}
}
}
|
