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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.
// Coroutines represent nothing more than a context and a stack
// segment.
use std::rt::env;
use context::Context;
use stack::{StackPool, StackSegment};
/// A coroutine is nothing more than a (register context, stack) pair.
pub struct Coroutine {
/// The segment of stack on which the task is currently running or
/// if the task is blocked, on which the task will resume
/// execution.
///
/// Servo needs this to be public in order to tell SpiderMonkey
/// about the stack bounds.
current_stack_segment: StackSegment,
/// Always valid if the task is alive and not running.
saved_context: Context
}
impl Coroutine {
pub fn new(stack_pool: &mut StackPool,
stack_size: Option<uint>,
start: proc())
-> Coroutine {
let stack_size = match stack_size {
Some(size) => size,
None => env::min_stack()
};
let mut stack = stack_pool.take_segment(stack_size);
let initial_context = Context::new(start, &mut stack);
Coroutine {
current_stack_segment: stack,
saved_context: initial_context
}
}
pub fn empty() -> Coroutine {
Coroutine {
current_stack_segment: StackSegment::new(0),
saved_context: Context::empty()
}
}
/// Destroy coroutine and try to reuse std::stack segment.
pub fn recycle(self, stack_pool: &mut StackPool) {
let Coroutine { current_stack_segment, .. } = self;
stack_pool.give_segment(current_stack_segment);
}
}
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