Brian Anderson brson

This is a prototype task scheduler, written in Rust, that is driven by an abstract event loop, along with the beginnings of an I/O interface for translating asynchronous I/O to synchronous I/O via scheduler context switches. It is part of issue #4419.

It is not ready to merge, but this is an opportunity to review and discuss.

While I am primarily interested in proving the integration of I/O with the scheduler, this is also written with a number of other goals in mind:

Replacing C++ code with Rust
Clean up stack management (#2044, #4479, #4480)
Supporting the work stealing algorithm (#3095)
Providing scheduling operations for different scenarios, some that avoid memory synchronization.

A simple test of read performance, newsched (-O) vs. node. The server command is yes | netcat -v -v -l 127.0.0.1 2931.

node:

var net = require('net');
var total = 0;
var client = net.connect(2931,
                         function() {
                             console.log('connected');

Both resume_task_from_queue and callback take &mut self

            fn run_scheduler_once() {
                do Scheduler::local |scheduler| {
                    if scheduler.resume_task_from_queue() {
                        // Ok, a task ran. Nice! We'll do it again later
                        scheduler.event_loop.callback(run_scheduler_once);
                    }
                }

	<core-macros>:17:32: 17:39 error: mismatched types: expected `~str` but found `&static/str` (str storage differs: expected ~ but found &static)
	<core-macros>:17 let _: &~str = &($msg);
	^~~~~~~
	<core-macros>:13:4: 1:0 note: in expansion of die!
	/home/brian/dev/rust/src/test/compile-fail/die-not-unique.rs:2:4: 2:17 note: expansion site
	/home/brian/dev/rust/src/test/compile-fail/die-not-unique.rs:2:9: 2:15 error: mismatched types: expected `~str` but found `&static/str` (str storage differs: expected ~ but found &static)
	/home/brian/dev/rust/src/test/compile-fail/die-not-unique.rs:2 die!("test"); //~ ERROR what
	^~~~~~
	<core-macros>:13:4: 1:0 note: in expansion of die!
	/home/brian/dev/rust/src/test/compile-fail/die-not-unique.rs:2:4: 2:17 note: expansion site

	Mozilla and the Rust community are pleased to announce version 0.5 of
	the Rust compiler and associated tools.

	The brief release notes are included in this announcement, and there is
	further explanation in the detailed release [notes] on the wiki.
	Documentation and all the links in this email are available on the
	[website]. As usual, version 0.5 should be considered an alpha release,
	suitable for early adopters and language enthusiasts. Please file [bugs].

	[notes]: https://github.com/mozilla/rust/wiki/Doc-detailed-release-notes

	pub trait Trig<T> {
	pure fn sin(&self) -> T;
	}

	pub trait Angle<T>: Trig<T> {}

	//type Trait<R> = Trig<R>;
	type Trait<R> = Angle<R>;

	pub fn sin<A:Trait<R>, R>(theta: &A) -> R { theta.sin() }

	The UI is nice.

	Output is now in `~/.rustpkg`, not `./.rustpkg`, and I don't see an option to use the local directory. We made cargo use the current directory instead of the user's directory to be like npm and isolate projects from each other. I don't want my four Rust workspaces all competing over resources under `~/.rustpkg`, and I don't want to wipe out all my builds globally when something goes wrong in one project

	Trying to run `hunter`:

	* When I `rustpkg build` inside the `rustpkg-test2` directory I build a binary that ends up ... somewhere
	* I tried to `rustpkg prefer hunter` but 'package not found'
	* Then I `rustpkg install` and that did something different
	* Then `rustpkg prefer hunter` and finally my binary moves to `~/.rustpkg/bin`

	# Useful Rust runtime tasks

	https://github.com/mozilla/rust/issues/4770 port pipes to pthreads
	https://github.com/mozilla/rust/issues/4768 remove dec_weak_task
	https://github.com/mozilla/rust/issues/4392 remove lazy scheduler initialization
	https://github.com/mozilla/rust/issues/3309 redesign logging - convert to task/pipe-based Rust
	https://github.com/mozilla/rust/issues/2044 extract all the stack management from rust_task
	https://github.com/mozilla/rust/issues/3695 change behavior of out-of-stack errors (graydon may have this on a branch)
	https://github.com/mozilla/rust/issues/3406 rewrite rust_start in rust
	https://github.com/mozilla/rust/issues/4812 rewrite various helper functions in rust

	pub fn spawn(f: ~fn()) {
	do task::task().sched_mode(task::PlatformThread).spawn {
	use core::private::finally::Finally;
	do (\|\| {
	// task work goes here
	}).finally {
	// terminate runs inside the task
	terminate();
	}
	}

	pub struct VariantDoc {
	desc: Option<~str>,
	sig: Option<~str>
	}

	fn main() {
	let variants = ~[
	VariantDoc {
	desc: None,
	sig: None