6987ad22e4
Previously, the entire runtime API surface was publicly exposed, but that is neither necessary nor desirable. This commit hides most of the module, using librustrt directly as needed. The arrangement will need to be revisited when rustrt is pulled into std. [breaking-change]
528 lines
16 KiB
Rust
528 lines
16 KiB
Rust
// Copyright 2012-2013 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.
|
|
|
|
//! Task creation
|
|
//!
|
|
//! An executing Rust program consists of a collection of tasks, each
|
|
//! with their own stack and local state.
|
|
//!
|
|
//! Tasks generally have their memory *isolated* from each other by
|
|
//! virtue of Rust's owned types (which of course may only be owned by
|
|
//! a single task at a time). Communication between tasks is primarily
|
|
//! done through [channels](../../std/comm/index.html), Rust's
|
|
//! message-passing types, though [other forms of task
|
|
//! synchronization](../../std/sync/index.html) are often employed to
|
|
//! achieve particular performance goals. In particular, types that
|
|
//! are guaranteed to be threadsafe are easily shared between threads
|
|
//! using the atomically-reference-counted container,
|
|
//! [`Arc`](../../std/sync/struct.Arc.html).
|
|
//!
|
|
//! Fatal logic errors in Rust cause *task panic*, during which
|
|
//! a task will unwind the stack, running destructors and freeing
|
|
//! owned resources. Task panic is unrecoverable from within
|
|
//! the panicking task (i.e. there is no 'try/catch' in Rust), but
|
|
//! panic may optionally be detected from a different task. If
|
|
//! the main task panics the application will exit with a non-zero
|
|
//! exit code.
|
|
//!
|
|
//! ## Example
|
|
//!
|
|
//! ```rust
|
|
//! spawn(proc() {
|
|
//! println!("Hello, World!");
|
|
//! })
|
|
//! ```
|
|
|
|
#![unstable = "The task spawning model will be changed as part of runtime reform, and the module \
|
|
will likely be renamed from `task` to `thread`."]
|
|
|
|
use any::Any;
|
|
use comm::channel;
|
|
use io::{Writer, stdio};
|
|
use kinds::{Send, marker};
|
|
use option::{None, Some, Option};
|
|
use boxed::Box;
|
|
use result::Result;
|
|
use rustrt::local::Local;
|
|
use rustrt::task;
|
|
use rustrt::task::Task;
|
|
use str::{Str, SendStr, IntoMaybeOwned};
|
|
use string::{String, ToString};
|
|
use sync::Future;
|
|
|
|
/// The task builder type.
|
|
///
|
|
/// Provides detailed control over the properties and behavior of new tasks.
|
|
|
|
// NB: Builders are designed to be single-use because they do stateful
|
|
// things that get weird when reusing - e.g. if you create a result future
|
|
// it only applies to a single task, so then you have to maintain Some
|
|
// potentially tricky state to ensure that everything behaves correctly
|
|
// when you try to reuse the builder to spawn a new task. We'll just
|
|
// sidestep that whole issue by making builders uncopyable and making
|
|
// the run function move them in.
|
|
pub struct TaskBuilder {
|
|
// A name for the task-to-be, for identification in panic messages
|
|
name: Option<SendStr>,
|
|
// The size of the stack for the spawned task
|
|
stack_size: Option<uint>,
|
|
// Task-local stdout
|
|
stdout: Option<Box<Writer + Send>>,
|
|
// Task-local stderr
|
|
stderr: Option<Box<Writer + Send>>,
|
|
// Optionally wrap the eventual task body
|
|
gen_body: Option<proc(v: proc():Send):Send -> proc():Send>,
|
|
nocopy: marker::NoCopy,
|
|
}
|
|
|
|
impl TaskBuilder {
|
|
/// Generate the base configuration for spawning a task, off of which more
|
|
/// configuration methods can be chained.
|
|
pub fn new() -> TaskBuilder {
|
|
TaskBuilder {
|
|
name: None,
|
|
stack_size: None,
|
|
stdout: None,
|
|
stderr: None,
|
|
gen_body: None,
|
|
nocopy: marker::NoCopy,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl TaskBuilder {
|
|
/// Name the task-to-be. Currently the name is used for identification
|
|
/// only in panic messages.
|
|
#[unstable = "IntoMaybeOwned will probably change."]
|
|
pub fn named<T: IntoMaybeOwned<'static>>(mut self, name: T) -> TaskBuilder {
|
|
self.name = Some(name.into_maybe_owned());
|
|
self
|
|
}
|
|
|
|
/// Set the size of the stack for the new task.
|
|
pub fn stack_size(mut self, size: uint) -> TaskBuilder {
|
|
self.stack_size = Some(size);
|
|
self
|
|
}
|
|
|
|
/// Redirect task-local stdout.
|
|
#[experimental = "May not want to make stdio overridable here."]
|
|
pub fn stdout(mut self, stdout: Box<Writer + Send>) -> TaskBuilder {
|
|
self.stdout = Some(stdout);
|
|
self
|
|
}
|
|
|
|
/// Redirect task-local stderr.
|
|
#[experimental = "May not want to make stdio overridable here."]
|
|
pub fn stderr(mut self, stderr: Box<Writer + Send>) -> TaskBuilder {
|
|
self.stderr = Some(stderr);
|
|
self
|
|
}
|
|
|
|
// Where spawning actually happens (whether yielding a future or not)
|
|
fn spawn_internal(self, f: proc():Send,
|
|
on_exit: Option<proc(Result<(), Box<Any + Send>>):Send>) {
|
|
let TaskBuilder {
|
|
name, stack_size, stdout, stderr, mut gen_body, nocopy: _
|
|
} = self;
|
|
let f = match gen_body.take() {
|
|
Some(gen) => gen(f),
|
|
None => f
|
|
};
|
|
let opts = task::TaskOpts {
|
|
on_exit: on_exit,
|
|
name: name,
|
|
stack_size: stack_size,
|
|
};
|
|
if stdout.is_some() || stderr.is_some() {
|
|
Task::spawn(opts, proc() {
|
|
let _ = stdout.map(stdio::set_stdout);
|
|
let _ = stderr.map(stdio::set_stderr);
|
|
f();
|
|
})
|
|
} else {
|
|
Task::spawn(opts, f)
|
|
}
|
|
}
|
|
|
|
/// Creates and executes a new child task.
|
|
///
|
|
/// Sets up a new task with its own call stack and schedules it to run
|
|
/// the provided proc. The task has the properties and behavior
|
|
/// specified by the `TaskBuilder`.
|
|
pub fn spawn(self, f: proc():Send) {
|
|
self.spawn_internal(f, None)
|
|
}
|
|
|
|
/// Execute a proc in a newly-spawned task and return a future representing
|
|
/// the task's result. The task has the properties and behavior
|
|
/// specified by the `TaskBuilder`.
|
|
///
|
|
/// Taking the value of the future will block until the child task
|
|
/// terminates.
|
|
///
|
|
/// # Return value
|
|
///
|
|
/// If the child task executes successfully (without panicking) then the
|
|
/// future returns `result::Ok` containing the value returned by the
|
|
/// function. If the child task panics then the future returns `result::Err`
|
|
/// containing the argument to `panic!(...)` as an `Any` trait object.
|
|
#[experimental = "Futures are experimental."]
|
|
pub fn try_future<T:Send>(self, f: proc():Send -> T)
|
|
-> Future<Result<T, Box<Any + Send>>> {
|
|
// currently, the on_exit proc provided by librustrt only works for unit
|
|
// results, so we use an additional side-channel to communicate the
|
|
// result.
|
|
|
|
let (tx_done, rx_done) = channel(); // signal that task has exited
|
|
let (tx_retv, rx_retv) = channel(); // return value from task
|
|
|
|
let on_exit = proc(res) { let _ = tx_done.send_opt(res); };
|
|
self.spawn_internal(proc() { let _ = tx_retv.send_opt(f()); },
|
|
Some(on_exit));
|
|
|
|
Future::from_fn(proc() {
|
|
rx_done.recv().map(|_| rx_retv.recv())
|
|
})
|
|
}
|
|
|
|
/// Execute a function in a newly-spawnedtask and block until the task
|
|
/// completes or panics. Equivalent to `.try_future(f).unwrap()`.
|
|
#[unstable = "Error type may change."]
|
|
pub fn try<T:Send>(self, f: proc():Send -> T) -> Result<T, Box<Any + Send>> {
|
|
self.try_future(f).unwrap()
|
|
}
|
|
}
|
|
|
|
/* Convenience functions */
|
|
|
|
/// Creates and executes a new child task
|
|
///
|
|
/// Sets up a new task with its own call stack and schedules it to run
|
|
/// the provided unique closure.
|
|
///
|
|
/// This function is equivalent to `TaskBuilder::new().spawn(f)`.
|
|
pub fn spawn(f: proc(): Send) {
|
|
TaskBuilder::new().spawn(f)
|
|
}
|
|
|
|
/// Execute a function in a newly-spawned task and return either the return
|
|
/// value of the function or an error if the task panicked.
|
|
///
|
|
/// This is equivalent to `TaskBuilder::new().try`.
|
|
#[unstable = "Error type may change."]
|
|
pub fn try<T: Send>(f: proc(): Send -> T) -> Result<T, Box<Any + Send>> {
|
|
TaskBuilder::new().try(f)
|
|
}
|
|
|
|
/// Execute a function in another task and return a future representing the
|
|
/// task's result.
|
|
///
|
|
/// This is equivalent to `TaskBuilder::new().try_future`.
|
|
#[experimental = "Futures are experimental."]
|
|
pub fn try_future<T:Send>(f: proc():Send -> T) -> Future<Result<T, Box<Any + Send>>> {
|
|
TaskBuilder::new().try_future(f)
|
|
}
|
|
|
|
|
|
/* Lifecycle functions */
|
|
|
|
/// Read the name of the current task.
|
|
#[stable]
|
|
pub fn name() -> Option<String> {
|
|
use rustrt::task::Task;
|
|
|
|
let task = Local::borrow(None::<Task>);
|
|
match task.name {
|
|
Some(ref name) => Some(name.as_slice().to_string()),
|
|
None => None
|
|
}
|
|
}
|
|
|
|
/// Yield control to the task scheduler.
|
|
#[unstable = "Name will change."]
|
|
pub fn deschedule() {
|
|
use rustrt::task::Task;
|
|
Task::yield_now();
|
|
}
|
|
|
|
/// True if the running task is currently panicking (e.g. will return `true` inside a
|
|
/// destructor that is run while unwinding the stack after a call to `panic!()`).
|
|
#[unstable = "May move to a different module."]
|
|
pub fn failing() -> bool {
|
|
use rustrt::task::Task;
|
|
Local::borrow(None::<Task>).unwinder.unwinding()
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test {
|
|
use any::{Any, AnyRefExt};
|
|
use boxed::BoxAny;
|
|
use result;
|
|
use result::{Ok, Err};
|
|
use string::String;
|
|
use std::io::{ChanReader, ChanWriter};
|
|
use prelude::*;
|
|
use super::*;
|
|
|
|
// !!! These tests are dangerous. If something is buggy, they will hang, !!!
|
|
// !!! instead of exiting cleanly. This might wedge the buildbots. !!!
|
|
|
|
#[test]
|
|
fn test_unnamed_task() {
|
|
try(proc() {
|
|
assert!(name().is_none());
|
|
}).map_err(|_| ()).unwrap();
|
|
}
|
|
|
|
#[test]
|
|
fn test_owned_named_task() {
|
|
TaskBuilder::new().named("ada lovelace".to_string()).try(proc() {
|
|
assert!(name().unwrap() == "ada lovelace".to_string());
|
|
}).map_err(|_| ()).unwrap();
|
|
}
|
|
|
|
#[test]
|
|
fn test_static_named_task() {
|
|
TaskBuilder::new().named("ada lovelace").try(proc() {
|
|
assert!(name().unwrap() == "ada lovelace".to_string());
|
|
}).map_err(|_| ()).unwrap();
|
|
}
|
|
|
|
#[test]
|
|
fn test_send_named_task() {
|
|
TaskBuilder::new().named("ada lovelace".into_maybe_owned()).try(proc() {
|
|
assert!(name().unwrap() == "ada lovelace".to_string());
|
|
}).map_err(|_| ()).unwrap();
|
|
}
|
|
|
|
#[test]
|
|
fn test_run_basic() {
|
|
let (tx, rx) = channel();
|
|
TaskBuilder::new().spawn(proc() {
|
|
tx.send(());
|
|
});
|
|
rx.recv();
|
|
}
|
|
|
|
#[test]
|
|
fn test_try_future() {
|
|
let result = TaskBuilder::new().try_future(proc() {});
|
|
assert!(result.unwrap().is_ok());
|
|
|
|
let result = TaskBuilder::new().try_future(proc() -> () {
|
|
panic!();
|
|
});
|
|
assert!(result.unwrap().is_err());
|
|
}
|
|
|
|
#[test]
|
|
fn test_try_success() {
|
|
match try(proc() {
|
|
"Success!".to_string()
|
|
}).as_ref().map(|s| s.as_slice()) {
|
|
result::Ok("Success!") => (),
|
|
_ => panic!()
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_try_panic() {
|
|
match try(proc() {
|
|
panic!()
|
|
}) {
|
|
result::Err(_) => (),
|
|
result::Ok(()) => panic!()
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_spawn_sched() {
|
|
use clone::Clone;
|
|
|
|
let (tx, rx) = channel();
|
|
|
|
fn f(i: int, tx: Sender<()>) {
|
|
let tx = tx.clone();
|
|
spawn(proc() {
|
|
if i == 0 {
|
|
tx.send(());
|
|
} else {
|
|
f(i - 1, tx);
|
|
}
|
|
});
|
|
|
|
}
|
|
f(10, tx);
|
|
rx.recv();
|
|
}
|
|
|
|
#[test]
|
|
fn test_spawn_sched_childs_on_default_sched() {
|
|
let (tx, rx) = channel();
|
|
|
|
spawn(proc() {
|
|
spawn(proc() {
|
|
tx.send(());
|
|
});
|
|
});
|
|
|
|
rx.recv();
|
|
}
|
|
|
|
fn avoid_copying_the_body(spawnfn: |v: proc():Send|) {
|
|
let (tx, rx) = channel::<uint>();
|
|
|
|
let x = box 1;
|
|
let x_in_parent = (&*x) as *const int as uint;
|
|
|
|
spawnfn(proc() {
|
|
let x_in_child = (&*x) as *const int as uint;
|
|
tx.send(x_in_child);
|
|
});
|
|
|
|
let x_in_child = rx.recv();
|
|
assert_eq!(x_in_parent, x_in_child);
|
|
}
|
|
|
|
#[test]
|
|
fn test_avoid_copying_the_body_spawn() {
|
|
avoid_copying_the_body(spawn);
|
|
}
|
|
|
|
#[test]
|
|
fn test_avoid_copying_the_body_task_spawn() {
|
|
avoid_copying_the_body(|f| {
|
|
let builder = TaskBuilder::new();
|
|
builder.spawn(proc() {
|
|
f();
|
|
});
|
|
})
|
|
}
|
|
|
|
#[test]
|
|
fn test_avoid_copying_the_body_try() {
|
|
avoid_copying_the_body(|f| {
|
|
let _ = try(proc() {
|
|
f()
|
|
});
|
|
})
|
|
}
|
|
|
|
#[test]
|
|
fn test_child_doesnt_ref_parent() {
|
|
// If the child refcounts the parent task, this will stack overflow when
|
|
// climbing the task tree to dereference each ancestor. (See #1789)
|
|
// (well, it would if the constant were 8000+ - I lowered it to be more
|
|
// valgrind-friendly. try this at home, instead..!)
|
|
static GENERATIONS: uint = 16;
|
|
fn child_no(x: uint) -> proc(): Send {
|
|
return proc() {
|
|
if x < GENERATIONS {
|
|
TaskBuilder::new().spawn(child_no(x+1));
|
|
}
|
|
}
|
|
}
|
|
TaskBuilder::new().spawn(child_no(0));
|
|
}
|
|
|
|
#[test]
|
|
fn test_simple_newsched_spawn() {
|
|
spawn(proc()())
|
|
}
|
|
|
|
#[test]
|
|
fn test_try_panic_message_static_str() {
|
|
match try(proc() {
|
|
panic!("static string");
|
|
}) {
|
|
Err(e) => {
|
|
type T = &'static str;
|
|
assert!(e.is::<T>());
|
|
assert_eq!(*e.downcast::<T>().unwrap(), "static string");
|
|
}
|
|
Ok(()) => panic!()
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_try_panic_message_owned_str() {
|
|
match try(proc() {
|
|
panic!("owned string".to_string());
|
|
}) {
|
|
Err(e) => {
|
|
type T = String;
|
|
assert!(e.is::<T>());
|
|
assert_eq!(*e.downcast::<T>().unwrap(), "owned string".to_string());
|
|
}
|
|
Ok(()) => panic!()
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_try_panic_message_any() {
|
|
match try(proc() {
|
|
panic!(box 413u16 as Box<Any + Send>);
|
|
}) {
|
|
Err(e) => {
|
|
type T = Box<Any + Send>;
|
|
assert!(e.is::<T>());
|
|
let any = e.downcast::<T>().unwrap();
|
|
assert!(any.is::<u16>());
|
|
assert_eq!(*any.downcast::<u16>().unwrap(), 413u16);
|
|
}
|
|
Ok(()) => panic!()
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_try_panic_message_unit_struct() {
|
|
struct Juju;
|
|
|
|
match try(proc() {
|
|
panic!(Juju)
|
|
}) {
|
|
Err(ref e) if e.is::<Juju>() => {}
|
|
Err(_) | Ok(()) => panic!()
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_stdout() {
|
|
let (tx, rx) = channel();
|
|
let mut reader = ChanReader::new(rx);
|
|
let stdout = ChanWriter::new(tx);
|
|
|
|
let r = TaskBuilder::new().stdout(box stdout as Box<Writer + Send>)
|
|
.try(proc() {
|
|
print!("Hello, world!");
|
|
});
|
|
assert!(r.is_ok());
|
|
|
|
let output = reader.read_to_string().unwrap();
|
|
assert_eq!(output, "Hello, world!".to_string());
|
|
}
|
|
|
|
// NOTE: the corresponding test for stderr is in run-pass/task-stderr, due
|
|
// to the test harness apparently interfering with stderr configuration.
|
|
}
|
|
|
|
#[test]
|
|
fn task_abort_no_kill_runtime() {
|
|
use std::io::timer;
|
|
use time::Duration;
|
|
use mem;
|
|
|
|
let tb = TaskBuilder::new();
|
|
let rx = tb.try_future(proc() {});
|
|
mem::drop(rx);
|
|
timer::sleep(Duration::milliseconds(1000));
|
|
}
|