Make DomRefCell not mutate the borrow flag non-atomically

servo · May 18, 2020 · 15db317 · 15db317
1 parent 45f1316
commit 15db317
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Showing 2 changed files with 6 additions and 5 deletions.
diff --git a/components/script/dom/bindings/cell.rs b/components/script/dom/bindings/cell.rs
@@ -45,11 +45,12 @@ impl<T> DomRefCell<T> {
         &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> {
+    /// Mutably borrow a cell for layout. Ideally this would use
+    /// `RefCell::try_borrow_mut_unguarded` but that doesn't exist yet.
+    #[allow(unsafe_code)]
+    pub unsafe fn borrow_mut_for_layout(&self) -> &mut T {
         debug_assert!(thread_state::get().is_layout());
-        self.value.borrow_mut()
+        &mut *self.value.as_ptr()
     }
 }
 

diff --git a/components/script/dom/shadowroot.rs b/components/script/dom/shadowroot.rs
@@ -281,7 +281,7 @@ impl<'dom> LayoutShadowRootHelpers<'dom> for LayoutDom<'dom, ShadowRoot> {
         quirks_mode: QuirksMode,
         guard: &SharedRwLockReadGuard,
     ) {
-        let mut author_styles = (*self.unsafe_get()).author_styles.borrow_mut_for_layout();
+        let author_styles = self.unsafe_get().author_styles.borrow_mut_for_layout();
         if author_styles.stylesheets.dirty() {
             author_styles.flush::<E>(device, quirks_mode, guard);
         }