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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
//! Supports dynamic assertions in debug builds about what sort of task is
//! running and what state it's in.
//!
//! In release builds, `get` returns 0. All of the other functions inline
//! away to nothing.
pub use self::imp::{initialize, get, enter, exit};
bitflags! {
#[derive(Show)]
flags TaskState: u32 {
const SCRIPT = 0x01,
const LAYOUT = 0x02,
const PAINT = 0x04,
const IN_WORKER = 0x0100,
const IN_GC = 0x0200,
const IN_HTML_PARSER = 0x0400,
}
}
macro_rules! task_types ( ( $( $fun:ident = $flag:ident ; )* ) => (
impl TaskState {
$(
pub fn $fun(self) -> bool {
self.contains($flag)
}
)*
}
#[cfg(not(ndebug))]
static TYPES: &'static [TaskState]
= &[ $( $flag ),* ];
));
task_types! {
is_script = SCRIPT;
is_layout = LAYOUT;
is_paint = PAINT;
}
#[cfg(not(ndebug))]
mod imp {
use super::{TaskState, TYPES};
use std::cell::RefCell;
thread_local!(static STATE: RefCell<Option<TaskState>> = RefCell::new(None));
pub fn initialize(x: TaskState) {
STATE.with(|ref k| {
match *k.borrow() {
Some(s) => panic!("Task state already initialized as {:?}", s),
None => ()
};
*k.borrow_mut() = Some(x);
});
get(); // check the assertion below
}
pub fn get() -> TaskState {
let state = STATE.with(|ref k| {
match *k.borrow() {
None => panic!("Task state not initialized"),
Some(s) => s,
}
});
// Exactly one of the task type flags should be set.
assert_eq!(1, TYPES.iter().filter(|&&ty| state.contains(ty)).count());
state
}
pub fn enter(x: TaskState) {
let state = get();
assert!(!state.intersects(x));
STATE.with(|ref k| {
*k.borrow_mut() = Some(state | x);
})
}
pub fn exit(x: TaskState) {
let state = get();
assert!(state.contains(x));
STATE.with(|ref k| {
*k.borrow_mut() = Some(state & !x);
})
}
}
#[cfg(ndebug)]
mod imp {
use super::TaskState;
#[inline(always)] pub fn initialize(_: TaskState) { }
#[inline(always)] pub fn get() -> TaskState { TaskState::empty() }
#[inline(always)] pub fn enter(_: TaskState) { }
#[inline(always)] pub fn exit(_: TaskState) { }
}
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