Add DOMRefCell<T> for safe borrowing in layout.

This type simply wraps `RefCell<T>` to add the special method,
and introduce the method to return the pointer of the value contained in
itself, for used in layout task.
This commit is contained in:
Tetsuharu OHZEKI 2014-10-15 02:34:03 +09:00
parent f1c050531f
commit 80593d9cc5
2 changed files with 69 additions and 0 deletions

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@ -0,0 +1,68 @@
/* 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/. */
use dom::bindings::trace::JSTraceable;
use js::jsapi::{JSTracer};
use std::cell;
use std::cell::RefCell;
use std::mem;
/// A mutable field in DOM for large sized value.
/// This has a special method to return the pointer of itself
/// for used in layout task.
/// This simply wraps `RefCell<T>` to add the special method.
pub struct DOMRefCell<T> {
base: RefCell<T>,
}
pub type Ref<'a, T> = cell::Ref<'a, T>;
pub type RefMut<'a, T> = cell::RefMut<'a, T>;
impl<T> DOMRefCell<T> {
#[inline(always)]
pub fn new(value: T) -> DOMRefCell<T> {
DOMRefCell {
base: RefCell::new(value),
}
}
#[inline(always)]
pub fn unwrap(self) -> T {
self.base.unwrap()
}
#[inline(always)]
pub fn try_borrow<'a>(&'a self) -> Option<Ref<'a, T>> {
self.base.try_borrow()
}
#[inline(always)]
pub fn borrow<'a>(&'a self) -> Ref<'a, T> {
self.base.borrow()
}
#[inline(always)]
pub fn try_borrow_mut<'a>(&'a self) -> Option<RefMut<'a, T>> {
self.base.try_borrow_mut()
}
#[inline(always)]
pub fn borrow_mut<'a>(&'a self) -> RefMut<'a, T> {
self.base.borrow_mut()
}
/// This returns the pointer which refers T in `RefCell<T>` directly.
pub unsafe fn borrow_for_layout<'a>(&'a self) -> &'a T {
let val = mem::transmute::<&RefCell<T>, &T>(&self.base);
val
}
}
impl<T: JSTraceable> JSTraceable for DOMRefCell<T> {
fn trace(&self, trc: *mut JSTracer) {
(*self).base.borrow().trace(trc)
}
}

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@ -56,6 +56,7 @@ pub mod dom {
/// The code to expose the DOM to JavaScript through IDL bindings.
pub mod bindings {
pub mod cell;
pub mod global;
pub mod js;
pub mod utils;