Move DOMRefCell back into script.

We’re not using it in style after all.
This commit is contained in:
Simon Sapin 2016-09-28 02:28:59 +02:00
parent 89a29a7f12
commit c831369e3e
4 changed files with 5 additions and 8 deletions

View file

@ -0,0 +1,135 @@
/* 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/. */
//! A shareable mutable container for the DOM.
use style::refcell::{BorrowError, BorrowMutError, Ref, RefCell, RefMut};
use style::thread_state;
/// A mutable field in the DOM.
///
/// This extends the API of `core::cell::RefCell` to allow unsafe access in
/// certain situations, with dynamic checking in debug builds.
#[derive(Clone, PartialEq, Debug, HeapSizeOf)]
pub struct DOMRefCell<T> {
value: RefCell<T>,
}
// FIXME: These two impls make promises that are not quite true,
// but maybe the debug_assert! makes it close enough.
#[allow(unsafe_code)]
unsafe impl<T: Send> Send for DOMRefCell<T> {}
#[allow(unsafe_code)]
unsafe impl<T: Sync> Sync for DOMRefCell<T> {}
// Functionality specific to Servo's `DOMRefCell` type
// ===================================================
impl<T> DOMRefCell<T> {
/// Return a reference to the contents.
///
/// For use in the layout thread only.
#[allow(unsafe_code)]
pub unsafe fn borrow_for_layout(&self) -> &T {
debug_assert!(thread_state::get().is_layout());
&*self.value.as_ptr()
}
/// Borrow the contents for the purpose of GC tracing.
///
/// This succeeds even if the object is mutably borrowed,
/// so you have to be careful in trace code!
#[allow(unsafe_code)]
pub unsafe fn borrow_for_gc_trace(&self) -> &T {
// FIXME: IN_GC isn't reliable enough - doesn't catch minor GCs
// https://github.com/servo/servo/issues/6389
// debug_assert!(thread_state::get().contains(SCRIPT | IN_GC));
&*self.value.as_ptr()
}
/// Borrow the contents for the purpose of script deallocation.
///
#[allow(unsafe_code)]
pub unsafe fn borrow_for_script_deallocation(&self) -> &mut T {
debug_assert!(thread_state::get().contains(thread_state::SCRIPT));
&mut *self.value.as_ptr()
}
/// Version of the above that we use during restyle while the script thread
/// is blocked.
pub fn borrow_mut_for_layout(&self) -> RefMut<T> {
debug_assert!(thread_state::get().is_layout());
self.value.borrow_mut()
}
}
// Functionality duplicated with `core::cell::RefCell`
// ===================================================
impl<T> DOMRefCell<T> {
/// Create a new `DOMRefCell` containing `value`.
pub fn new(value: T) -> DOMRefCell<T> {
DOMRefCell {
value: RefCell::new(value),
}
}
/// Immutably borrows the wrapped value.
///
/// The borrow lasts until the returned `Ref` exits scope. Multiple
/// immutable borrows can be taken out at the same time.
///
/// # Panics
///
/// Panics if this is called off the script thread.
///
/// Panics if the value is currently mutably borrowed.
pub fn borrow(&self) -> Ref<T> {
self.try_borrow().expect("DOMRefCell<T> already mutably borrowed")
}
/// Mutably borrows the wrapped value.
///
/// The borrow lasts until the returned `RefMut` exits scope. The value
/// cannot be borrowed while this borrow is active.
///
/// # Panics
///
/// Panics if this is called off the script thread.
///
/// Panics if the value is currently borrowed.
pub fn borrow_mut(&self) -> RefMut<T> {
self.try_borrow_mut().expect("DOMRefCell<T> already borrowed")
}
/// Attempts to immutably borrow the wrapped value.
///
/// The borrow lasts until the returned `Ref` exits scope. Multiple
/// immutable borrows can be taken out at the same time.
///
/// Returns `None` if the value is currently mutably borrowed.
///
/// # Panics
///
/// Panics if this is called off the script thread.
pub fn try_borrow(&self) -> Result<Ref<T>, BorrowError<T>> {
debug_assert!(thread_state::get().is_script());
self.value.try_borrow()
}
/// Mutably borrows the wrapped value.
///
/// The borrow lasts until the returned `RefMut` exits scope. The value
/// cannot be borrowed while this borrow is active.
///
/// Returns `None` if the value is currently borrowed.
///
/// # Panics
///
/// Panics if this is called off the script thread.
pub fn try_borrow_mut(&self) -> Result<RefMut<T>, BorrowMutError<T>> {
debug_assert!(thread_state::get().is_script());
self.value.try_borrow_mut()
}
}

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@ -128,9 +128,8 @@
//! return `Err()` from the method with the appropriate [error value]
//! (error/enum.Error.html).
pub use style::domrefcell as cell;
pub mod callback;
pub mod cell;
pub mod constant;
pub mod conversions;
pub mod error;

View file

@ -35,6 +35,7 @@ use cssparser::RGBA;
use devtools_traits::CSSError;
use devtools_traits::WorkerId;
use dom::abstractworker::SharedRt;
use dom::bindings::cell::DOMRefCell;
use dom::bindings::js::{JS, Root};
use dom::bindings::refcounted::{Trusted, TrustedPromise};
use dom::bindings::reflector::{Reflectable, Reflector};
@ -89,7 +90,6 @@ use std::sync::mpsc::{Receiver, Sender};
use std::time::{SystemTime, Instant};
use string_cache::{Atom, Namespace, QualName};
use style::attr::{AttrIdentifier, AttrValue, LengthOrPercentageOrAuto};
use style::domrefcell::DOMRefCell;
use style::element_state::*;
use style::properties::PropertyDeclarationBlock;
use style::selector_impl::{ElementSnapshot, PseudoElement};