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Reorganise Select traits to not expose internal runtime types. Close #5160. Pending #8215.

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This commit is contained in:
Ben Blum 2013-08-08 18:34:10 -04:00
parent ee5cfb0c2d
commit c8c09d40fc
5 changed files with 348 additions and 313 deletions
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23
src/libstd/rt/comm.rs
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@ -18,7 +18,8 @@ use kinds::Send;
use rt;
use rt::sched::Scheduler;
use rt::local::Local;
use rt::select::{Select, SelectPort};
use rt::select::{SelectInner, SelectPortInner};
use select::{Select, SelectPort};
use unstable::atomics::{AtomicUint, AtomicOption, Acquire, Relaxed, SeqCst};
use unstable::sync::UnsafeAtomicRcBox;
use util::Void;
@ -215,7 +216,7 @@ impl<T> PortOne<T> {
}
}
impl<T> Select for PortOne<T> {
impl<T> SelectInner for PortOne<T> {
#[inline] #[cfg(not(test))]
fn optimistic_check(&mut self) -> bool {
unsafe { (*self.packet()).state.load(Acquire) == STATE_ONE }
@ -318,7 +319,9 @@ impl<T> Select for PortOne<T> {
}
}
impl<T> SelectPort<T> for PortOne<T> {
impl<T> Select for PortOne<T> { }
impl<T> SelectPortInner<T> for PortOne<T> {
fn recv_ready(self) -> Option<T> {
let mut this = self;
let packet = this.packet();
@ -349,6 +352,8 @@ impl<T> SelectPort<T> for PortOne<T> {
}
}
impl<T> SelectPort<T> for PortOne<T> { }
impl<T> Peekable<T> for PortOne<T> {
fn peek(&self) -> bool {
unsafe {
@ -513,7 +518,7 @@ impl<T> Peekable<T> for Port<T> {
// of them, but a &Port<T> should also be selectable so you can select2 on it
// alongside a PortOne<U> without passing the port by value in recv_ready.
impl<'self, T> Select for &'self Port<T> {
impl<'self, T> SelectInner for &'self Port<T> {
#[inline]
fn optimistic_check(&mut self) -> bool {
do self.next.with_mut_ref |pone| { pone.optimistic_check() }
@ -531,7 +536,9 @@ impl<'self, T> Select for &'self Port<T> {
}
}
impl<T> Select for Port<T> {
impl<'self, T> Select for &'self Port<T> { }
impl<T> SelectInner for Port<T> {
#[inline]
fn optimistic_check(&mut self) -> bool {
(&*self).optimistic_check()
@ -548,7 +555,9 @@ impl<T> Select for Port<T> {
}
}
impl<'self, T> SelectPort<T> for &'self Port<T> {
impl<T> Select for Port<T> { }
impl<'self, T> SelectPortInner<T> for &'self Port<T> {
fn recv_ready(self) -> Option<T> {
match self.next.take().recv_ready() {
Some(StreamPayload { val, next }) => {
@ -560,6 +569,8 @@ impl<'self, T> SelectPort<T> for &'self Port<T> {
}
}
impl<'self, T> SelectPort<T> for &'self Port<T> { }
pub struct SharedChan<T> {
// Just like Chan, but a shared AtomicOption instead of Cell
priv next: UnsafeAtomicRcBox<AtomicOption<StreamChanOne<T>>>

3
src/libstd/rt/mod.rs
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@ -142,8 +142,7 @@ pub mod tube;
/// Simple reimplementation of core::comm
pub mod comm;
/// Routines for select()ing on pipes.
pub mod select;
mod select;
// FIXME #5248 shouldn't be pub
/// The runtime needs to be able to put a pointer into thread-local storage.

310
src/libstd/rt/select.rs
View File

@ -8,14 +8,13 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use option::*;
// use either::{Either, Left, Right};
//! Module for private, abstraction-leaking select traits. Wrapped in std::select.
use rt::kill::BlockedTask;
use rt::sched::Scheduler;
use rt::local::Local;
use option::Option;
/// Trait for message-passing primitives that can be select()ed on.
pub trait Select {
pub trait SelectInner {
// Returns true if data was available.
fn optimistic_check(&mut self) -> bool;
// Returns true if data was available. If so, shall also wake() the task.
@ -24,305 +23,6 @@ pub trait Select {
fn unblock_from(&mut self) -> bool;
}
/// Trait for message-passing primitives that can use the select2() convenience wrapper.
// (This is separate from the above trait to enable heterogeneous lists of ports
// that implement Select on different types to use select().)
pub trait SelectPort<T> : Select {
pub trait SelectPortInner<T> {
fn recv_ready(self) -> Option<T>;
}
/// Receive a message from any one of many ports at once.
pub fn select<A: Select>(ports: &mut [A]) -> uint {
if ports.is_empty() {
fail!("can't select on an empty list");
}
for (index, port) in ports.mut_iter().enumerate() {
if port.optimistic_check() {
return index;
}
}
// If one of the ports already contains data when we go to block on it, we
// don't bother enqueueing on the rest of them, so we shouldn't bother
// unblocking from it either. This is just for efficiency, not correctness.
// (If not, we need to unblock from all of them. Length is a placeholder.)
let mut ready_index = ports.len();
let sched = Local::take::<Scheduler>();
do sched.deschedule_running_task_and_then |sched, task| {
let task_handles = task.make_selectable(ports.len());
for (index, (port, task_handle)) in
ports.mut_iter().zip(task_handles.move_iter()).enumerate() {
// If one of the ports has data by now, it will wake the handle.
if port.block_on(sched, task_handle) {
ready_index = index;
break;
}
}
}
// Task resumes. Now unblock ourselves from all the ports we blocked on.
// If the success index wasn't reset, 'take' will just take all of them.
// Iterate in reverse so the 'earliest' index that's ready gets returned.
for (index, port) in ports.mut_slice(0, ready_index).mut_rev_iter().enumerate() {
if port.unblock_from() {
ready_index = index;
}
}
assert!(ready_index < ports.len());
return ready_index;
}
/* FIXME(#5121, #7914) This all should be legal, but rust is not clever enough yet.
impl <'self> Select for &'self mut Select {
fn optimistic_check(&mut self) -> bool { self.optimistic_check() }
fn block_on(&mut self, sched: &mut Scheduler, task: BlockedTask) -> bool {
self.block_on(sched, task)
}
fn unblock_from(&mut self) -> bool { self.unblock_from() }
}
pub fn select2<TA, A: SelectPort<TA>, TB, B: SelectPort<TB>>(mut a: A, mut b: B)
-> Either<(Option<TA>, B), (A, Option<TB>)> {
let result = {
let mut ports = [&mut a as &mut Select, &mut b as &mut Select];
select(ports)
};
match result {
0 => Left ((a.recv_ready(), b)),
1 => Right((a, b.recv_ready())),
x => fail!("impossible case in select2: %?", x)
}
}
*/
#[cfg(test)]
mod test {
use super::*;
use option::*;
use rt::comm::*;
use rt::test::*;
use vec::*;
use comm::GenericChan;
use task;
use cell::Cell;
use iterator::{Iterator, range};
#[test] #[ignore(cfg(windows))] #[should_fail]
fn select_doesnt_get_trolled() {
select::<PortOne<()>>([]);
}
/* non-blocking select tests */
#[cfg(test)]
fn select_helper(num_ports: uint, send_on_chans: &[uint]) {
// Unfortunately this does not actually test the block_on early-break
// codepath in select -- racing between the sender and the receiver in
// separate tasks is necessary to get around the optimistic check.
let (ports, chans) = unzip(from_fn(num_ports, |_| oneshot::<()>()));
let mut dead_chans = ~[];
let mut ports = ports;
for (i, chan) in chans.move_iter().enumerate() {
if send_on_chans.contains(&i) {
chan.send(());
} else {
dead_chans.push(chan);
}
}
let ready_index = select(ports);
assert!(send_on_chans.contains(&ready_index));
assert!(ports.swap_remove(ready_index).recv_ready().is_some());
let _ = dead_chans;
// Same thing with streams instead.
// FIXME(#7971): This should be in a macro but borrowck isn't smart enough.
let (ports, chans) = unzip(from_fn(num_ports, |_| stream::<()>()));
let mut dead_chans = ~[];
let mut ports = ports;
for (i, chan) in chans.move_iter().enumerate() {
if send_on_chans.contains(&i) {
chan.send(());
} else {
dead_chans.push(chan);
}
}
let ready_index = select(ports);
assert!(send_on_chans.contains(&ready_index));
assert!(ports.swap_remove(ready_index).recv_ready().is_some());
let _ = dead_chans;
}
#[test]
fn select_one() {
do run_in_newsched_task { select_helper(1, [0]) }
}
#[test]
fn select_two() {
// NB. I would like to have a test that tests the first one that is
// ready is the one that's returned, but that can't be reliably tested
// with the randomized behaviour of optimistic_check.
do run_in_newsched_task { select_helper(2, [1]) }
do run_in_newsched_task { select_helper(2, [0]) }
do run_in_newsched_task { select_helper(2, [1,0]) }
}
#[test]
fn select_a_lot() {
do run_in_newsched_task { select_helper(12, [7,8,9]) }
}
#[test]
fn select_stream() {
use util;
use comm::GenericChan;
use iter::Times;
// Sends 10 buffered packets, and uses select to retrieve them all.
// Puts the port in a different spot in the vector each time.
do run_in_newsched_task {
let (ports, _) = unzip(from_fn(10, |_| stream()));
let (port, chan) = stream();
do 10.times { chan.send(31337); }
let mut ports = ports;
let mut port = Some(port);
let order = [5u,0,4,3,2,6,9,8,7,1];
for &index in order.iter() {
// put the port in the vector at any index
util::swap(port.get_mut_ref(), &mut ports[index]);
assert!(select(ports) == index);
// get it back out
util::swap(port.get_mut_ref(), &mut ports[index]);
// NB. Not recv(), because optimistic_check randomly fails.
assert!(port.get_ref().recv_ready().unwrap() == 31337);
}
}
}
#[test]
fn select_unkillable() {
do run_in_newsched_task {
do task::unkillable { select_helper(2, [1]) }
}
}
/* blocking select tests */
#[test]
fn select_blocking() {
select_blocking_helper(true);
select_blocking_helper(false);
fn select_blocking_helper(killable: bool) {
do run_in_newsched_task {
let (p1,_c) = oneshot();
let (p2,c2) = oneshot();
let mut ports = [p1,p2];
let (p3,c3) = oneshot();
let (p4,c4) = oneshot();
let x = Cell::new((c2, p3, c4));
do task::spawn {
let (c2, p3, c4) = x.take();
p3.recv(); // handshake parent
c4.send(()); // normal receive
task::yield();
c2.send(()); // select receive
}
// Try to block before child sends on c2.
c3.send(());
p4.recv();
if killable {
assert!(select(ports) == 1);
} else {
do task::unkillable { assert!(select(ports) == 1); }
}
}
}
}
#[test]
fn select_racing_senders() {
static NUM_CHANS: uint = 10;
select_racing_senders_helper(true, ~[0,1,2,3,4,5,6,7,8,9]);
select_racing_senders_helper(false, ~[0,1,2,3,4,5,6,7,8,9]);
select_racing_senders_helper(true, ~[0,1,2]);
select_racing_senders_helper(false, ~[0,1,2]);
select_racing_senders_helper(true, ~[3,4,5,6]);
select_racing_senders_helper(false, ~[3,4,5,6]);
select_racing_senders_helper(true, ~[7,8,9]);
select_racing_senders_helper(false, ~[7,8,9]);
fn select_racing_senders_helper(killable: bool, send_on_chans: ~[uint]) {
use rt::test::spawntask_random;
use iter::Times;
do run_in_newsched_task {
// A bit of stress, since ordinarily this is just smoke and mirrors.
do 4.times {
let send_on_chans = send_on_chans.clone();
do task::spawn {
let mut ports = ~[];
for i in range(0u, NUM_CHANS) {
let (p,c) = oneshot();
ports.push(p);
if send_on_chans.contains(&i) {
let c = Cell::new(c);
do spawntask_random {
task::yield();
c.take().send(());
}
}
}
// nondeterministic result, but should succeed
if killable {
select(ports);
} else {
do task::unkillable { select(ports); }
}
}
}
}
}
}
#[test] #[ignore(cfg(windows))]
fn select_killed() {
do run_in_newsched_task {
let (success_p, success_c) = oneshot::<bool>();
let success_c = Cell::new(success_c);
do task::try {
let success_c = Cell::new(success_c.take());
do task::unkillable {
let (p,c) = oneshot();
let c = Cell::new(c);
do task::spawn {
let (dead_ps, dead_cs) = unzip(from_fn(5, |_| oneshot::<()>()));
let mut ports = dead_ps;
select(ports); // should get killed; nothing should leak
c.take().send(()); // must not happen
// Make sure dead_cs doesn't get closed until after select.
let _ = dead_cs;
}
do task::spawn {
fail!(); // should kill sibling awake
}
// wait for killed selector to close (NOT send on) its c.
// hope to send 'true'.
success_c.take().send(p.try_recv().is_none());
}
};
assert!(success_p.recv());
}
}
}

324
src/libstd/select.rs Normal file
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@ -0,0 +1,324 @@
// 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.
use container::Container;
use iterator::Iterator;
use option::*;
// use either::{Either, Left, Right};
// use rt::kill::BlockedTask;
use rt::sched::Scheduler;
use rt::select::{SelectInner, SelectPortInner};
use rt::local::Local;
use vec::{OwnedVector, MutableVector};
/// Trait for message-passing primitives that can be select()ed on.
pub trait Select : SelectInner { }
/// Trait for message-passing primitives that can use the select2() convenience wrapper.
// (This is separate from the above trait to enable heterogeneous lists of ports
// that implement Select on different types to use select().)
pub trait SelectPort<T> : SelectPortInner<T> { }
/// Receive a message from any one of many ports at once. Returns the index of the
/// port whose data is ready. (If multiple are ready, returns the lowest index.)
pub fn select<A: Select>(ports: &mut [A]) -> uint {
if ports.is_empty() {
fail!("can't select on an empty list");
}
for (index, port) in ports.mut_iter().enumerate() {
if port.optimistic_check() {
return index;
}
}
// If one of the ports already contains data when we go to block on it, we
// don't bother enqueueing on the rest of them, so we shouldn't bother
// unblocking from it either. This is just for efficiency, not correctness.
// (If not, we need to unblock from all of them. Length is a placeholder.)
let mut ready_index = ports.len();
let sched = Local::take::<Scheduler>();
do sched.deschedule_running_task_and_then |sched, task| {
let task_handles = task.make_selectable(ports.len());
for (index, (port, task_handle)) in
ports.mut_iter().zip(task_handles.move_iter()).enumerate() {
// If one of the ports has data by now, it will wake the handle.
if port.block_on(sched, task_handle) {
ready_index = index;
break;
}
}
}
// Task resumes. Now unblock ourselves from all the ports we blocked on.
// If the success index wasn't reset, 'take' will just take all of them.
// Iterate in reverse so the 'earliest' index that's ready gets returned.
for (index, port) in ports.mut_slice(0, ready_index).mut_rev_iter().enumerate() {
if port.unblock_from() {
ready_index = index;
}
}
assert!(ready_index < ports.len());
return ready_index;
}
/* FIXME(#5121, #7914) This all should be legal, but rust is not clever enough yet.
impl <'self> Select for &'self mut Select {
fn optimistic_check(&mut self) -> bool { self.optimistic_check() }
fn block_on(&mut self, sched: &mut Scheduler, task: BlockedTask) -> bool {
self.block_on(sched, task)
}
fn unblock_from(&mut self) -> bool { self.unblock_from() }
}
pub fn select2<TA, A: SelectPort<TA>, TB, B: SelectPort<TB>>(mut a: A, mut b: B)
-> Either<(Option<TA>, B), (A, Option<TB>)> {
let result = {
let mut ports = [&mut a as &mut Select, &mut b as &mut Select];
select(ports)
};
match result {
0 => Left ((a.recv_ready(), b)),
1 => Right((a, b.recv_ready())),
x => fail!("impossible case in select2: %?", x)
}
}
*/
#[cfg(test)]
mod test {
use super::*;
use clone::Clone;
use iter::Times;
use option::*;
use rt::comm::*;
use rt::test::*;
use vec::*;
use comm::GenericChan;
use task;
use cell::Cell;
use iterator::{Iterator, range};
#[test] #[ignore(cfg(windows))] #[should_fail]
fn select_doesnt_get_trolled() {
select::<PortOne<()>>([]);
}
/* non-blocking select tests */
#[cfg(test)]
fn select_helper(num_ports: uint, send_on_chans: &[uint]) {
// Unfortunately this does not actually test the block_on early-break
// codepath in select -- racing between the sender and the receiver in
// separate tasks is necessary to get around the optimistic check.
let (ports, chans) = unzip(from_fn(num_ports, |_| oneshot::<()>()));
let mut dead_chans = ~[];
let mut ports = ports;
for (i, chan) in chans.move_iter().enumerate() {
if send_on_chans.contains(&i) {
chan.send(());
} else {
dead_chans.push(chan);
}
}
let ready_index = select(ports);
assert!(send_on_chans.contains(&ready_index));
assert!(ports.swap_remove(ready_index).recv_ready().is_some());
let _ = dead_chans;
// Same thing with streams instead.
// FIXME(#7971): This should be in a macro but borrowck isn't smart enough.
let (ports, chans) = unzip(from_fn(num_ports, |_| stream::<()>()));
let mut dead_chans = ~[];
let mut ports = ports;
for (i, chan) in chans.move_iter().enumerate() {
if send_on_chans.contains(&i) {
chan.send(());
} else {
dead_chans.push(chan);
}
}
let ready_index = select(ports);
assert!(send_on_chans.contains(&ready_index));
assert!(ports.swap_remove(ready_index).recv_ready().is_some());
let _ = dead_chans;
}
#[test]
fn select_one() {
do run_in_newsched_task { select_helper(1, [0]) }
}
#[test]
fn select_two() {
// NB. I would like to have a test that tests the first one that is
// ready is the one that's returned, but that can't be reliably tested
// with the randomized behaviour of optimistic_check.
do run_in_newsched_task { select_helper(2, [1]) }
do run_in_newsched_task { select_helper(2, [0]) }
do run_in_newsched_task { select_helper(2, [1,0]) }
}
#[test]
fn select_a_lot() {
do run_in_newsched_task { select_helper(12, [7,8,9]) }
}
#[test]
fn select_stream() {
use util;
use comm::GenericChan;
// Sends 10 buffered packets, and uses select to retrieve them all.
// Puts the port in a different spot in the vector each time.
do run_in_newsched_task {
let (ports, _) = unzip(from_fn(10, |_| stream()));
let (port, chan) = stream();
do 10.times { chan.send(31337); }
let mut ports = ports;
let mut port = Some(port);
let order = [5u,0,4,3,2,6,9,8,7,1];
for &index in order.iter() {
// put the port in the vector at any index
util::swap(port.get_mut_ref(), &mut ports[index]);
assert!(select(ports) == index);
// get it back out
util::swap(port.get_mut_ref(), &mut ports[index]);
// NB. Not recv(), because optimistic_check randomly fails.
assert!(port.get_ref().recv_ready().unwrap() == 31337);
}
}
}
#[test]
fn select_unkillable() {
do run_in_newsched_task {
do task::unkillable { select_helper(2, [1]) }
}
}
/* blocking select tests */
#[test]
fn select_blocking() {
select_blocking_helper(true);
select_blocking_helper(false);
fn select_blocking_helper(killable: bool) {
do run_in_newsched_task {
let (p1,_c) = oneshot();
let (p2,c2) = oneshot();
let mut ports = [p1,p2];
let (p3,c3) = oneshot();
let (p4,c4) = oneshot();
let x = Cell::new((c2, p3, c4));
do task::spawn {
let (c2, p3, c4) = x.take();
p3.recv(); // handshake parent
c4.send(()); // normal receive
task::yield();
c2.send(()); // select receive
}
// Try to block before child sends on c2.
c3.send(());
p4.recv();
if killable {
assert!(select(ports) == 1);
} else {
do task::unkillable { assert!(select(ports) == 1); }
}
}
}
}
#[test]
fn select_racing_senders() {
static NUM_CHANS: uint = 10;
select_racing_senders_helper(true, ~[0,1,2,3,4,5,6,7,8,9]);
select_racing_senders_helper(false, ~[0,1,2,3,4,5,6,7,8,9]);
select_racing_senders_helper(true, ~[0,1,2]);
select_racing_senders_helper(false, ~[0,1,2]);
select_racing_senders_helper(true, ~[3,4,5,6]);
select_racing_senders_helper(false, ~[3,4,5,6]);
select_racing_senders_helper(true, ~[7,8,9]);
select_racing_senders_helper(false, ~[7,8,9]);
fn select_racing_senders_helper(killable: bool, send_on_chans: ~[uint]) {
use rt::test::spawntask_random;
do run_in_newsched_task {
// A bit of stress, since ordinarily this is just smoke and mirrors.
do 4.times {
let send_on_chans = send_on_chans.clone();
do task::spawn {
let mut ports = ~[];
for i in range(0u, NUM_CHANS) {
let (p,c) = oneshot();
ports.push(p);
if send_on_chans.contains(&i) {
let c = Cell::new(c);
do spawntask_random {
task::yield();
c.take().send(());
}
}
}
// nondeterministic result, but should succeed
if killable {
select(ports);
} else {
do task::unkillable { select(ports); }
}
}
}
}
}
}
#[test] #[ignore(cfg(windows))]
fn select_killed() {
do run_in_newsched_task {
let (success_p, success_c) = oneshot::<bool>();
let success_c = Cell::new(success_c);
do task::try {
let success_c = Cell::new(success_c.take());
do task::unkillable {
let (p,c) = oneshot();
let c = Cell::new(c);
do task::spawn {
let (dead_ps, dead_cs) = unzip(from_fn(5, |_| oneshot::<()>()));
let mut ports = dead_ps;
select(ports); // should get killed; nothing should leak
c.take().send(()); // must not happen
// Make sure dead_cs doesn't get closed until after select.
let _ = dead_cs;
}
do task::spawn {
fail!(); // should kill sibling awake
}
// wait for killed selector to close (NOT send on) its c.
// hope to send 'true'.
success_c.take().send(p.try_recv().is_none());
}
};
assert!(success_p.recv());
}
}
}

1
src/libstd/std.rs
View File

@ -164,6 +164,7 @@ pub mod trie;
pub mod task;
pub mod comm;
pub mod select;
pub mod local_data;