Move DOMRefCell to style.

This commit is contained in:
Simon Sapin 2016-08-30 17:23:21 +02:00
parent ec723057b2
commit c87180a2fb
5 changed files with 16 additions and 17 deletions

View file

@ -1,139 +0,0 @@
/* 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 dom::bindings::trace::JSTraceable;
use js::jsapi::JSTracer;
use style::refcell::{BorrowError, BorrowMutError, Ref, RefCell, RefMut};
use style::thread_state;
use style::thread_state::SCRIPT;
/// 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, HeapSizeOf)]
pub struct DOMRefCell<T> {
value: RefCell<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(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()
}
}
impl<T: JSTraceable> JSTraceable for DOMRefCell<T> {
fn trace(&self, trc: *mut JSTracer) {
unsafe {
(*self).borrow_for_gc_trace().trace(trc)
}
}
}
// 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()
}
}

View file

@ -128,8 +128,9 @@
//! 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 conversions;
pub mod error;
pub mod global;

View file

@ -88,6 +88,7 @@ use std::sync::mpsc::{Receiver, Sender};
use std::time::SystemTime;
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::{PseudoElement, ElementSnapshot};
@ -172,6 +173,13 @@ impl<T: JSTraceable> JSTraceable for UnsafeCell<T> {
}
}
impl<T: JSTraceable> JSTraceable for DOMRefCell<T> {
fn trace(&self, trc: *mut JSTracer) {
unsafe {
(*self).borrow_for_gc_trace().trace(trc)
}
}
}
impl JSTraceable for Heap<*mut JSObject> {
fn trace(&self, trc: *mut JSTracer) {