1 files changed, 289 insertions, 0 deletions
diff --git a/components/script/dom/shadowroot.rs b/components/script/dom/shadowroot.rs
new file mode 100644
index 00000000000..c70c13d8cef
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+++ b/components/script/dom/shadowroot.rs
@@ -0,0 +1,289 @@
+/* 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 https://mozilla.org/MPL/2.0/. */
+
+use crate::dom::bindings::cell::DomRefCell;
+use crate::dom::bindings::codegen::Bindings::ShadowRootBinding::ShadowRootBinding::ShadowRootMethods;
+use crate::dom::bindings::codegen::Bindings::ShadowRootBinding::ShadowRootMode;
+use crate::dom::bindings::inheritance::Castable;
+use crate::dom::bindings::num::Finite;
+use crate::dom::bindings::reflector::reflect_dom_object;
+use crate::dom::bindings::root::{Dom, DomRoot, LayoutDom, MutNullableDom};
+use crate::dom::cssstylesheet::CSSStyleSheet;
+use crate::dom::document::Document;
+use crate::dom::documentfragment::DocumentFragment;
+use crate::dom::documentorshadowroot::{DocumentOrShadowRoot, StyleSheetInDocument};
+use crate::dom::element::Element;
+use crate::dom::node::{Node, NodeDamage, NodeFlags, ShadowIncluding, UnbindContext};
+use crate::dom::stylesheetlist::{StyleSheetList, StyleSheetListOwner};
+use crate::dom::window::Window;
+use crate::stylesheet_set::StylesheetSetRef;
+use dom_struct::dom_struct;
+use selectors::context::QuirksMode;
+use servo_arc::Arc;
+use servo_atoms::Atom;
+use style::author_styles::AuthorStyles;
+use style::dom::TElement;
+use style::media_queries::Device;
+use style::shared_lock::SharedRwLockReadGuard;
+use style::stylesheets::Stylesheet;
+use style::stylist::CascadeData;
+
+/// Whether a shadow root hosts an User Agent widget.
+#[derive(JSTraceable, MallocSizeOf, PartialEq)]
+pub enum IsUserAgentWidget {
+    No,
+    Yes,
+}
+
+// https://dom.spec.whatwg.org/#interface-shadowroot
+#[dom_struct]
+pub struct ShadowRoot {
+    document_fragment: DocumentFragment,
+    document_or_shadow_root: DocumentOrShadowRoot,
+    document: Dom<Document>,
+    host: MutNullableDom<Element>,
+    /// List of author styles associated with nodes in this shadow tree.
+    author_styles: DomRefCell<AuthorStyles<StyleSheetInDocument>>,
+    stylesheet_list: MutNullableDom<StyleSheetList>,
+    window: Dom<Window>,
+}
+
+impl ShadowRoot {
+    #[allow(unrooted_must_root)]
+    fn new_inherited(host: &Element, document: &Document) -> ShadowRoot {
+        let document_fragment = DocumentFragment::new_inherited(document);
+        let node = document_fragment.upcast::<Node>();
+        node.set_flag(NodeFlags::IS_IN_SHADOW_TREE, true);
+        node.set_flag(
+            NodeFlags::IS_CONNECTED,
+            host.upcast::<Node>().is_connected(),
+        );
+        ShadowRoot {
+            document_fragment,
+            document_or_shadow_root: DocumentOrShadowRoot::new(document.window()),
+            document: Dom::from_ref(document),
+            host: MutNullableDom::new(Some(host)),
+            author_styles: DomRefCell::new(AuthorStyles::new()),
+            stylesheet_list: MutNullableDom::new(None),
+            window: Dom::from_ref(document.window()),
+        }
+    }
+
+    pub fn new(host: &Element, document: &Document) -> DomRoot<ShadowRoot> {
+        reflect_dom_object(
+            Box::new(ShadowRoot::new_inherited(host, document)),
+            document.window(),
+        )
+    }
+
+    pub fn detach(&self) {
+        self.document.unregister_shadow_root(&self);
+        let node = self.upcast::<Node>();
+        node.set_containing_shadow_root(None);
+        Node::complete_remove_subtree(&node, &UnbindContext::new(node, None, None, None));
+        self.host.set(None);
+    }
+
+    pub fn get_focused_element(&self) -> Option<DomRoot<Element>> {
+        //XXX get retargeted focused element
+        None
+    }
+
+    pub fn stylesheet_count(&self) -> usize {
+        self.author_styles.borrow().stylesheets.len()
+    }
+
+    pub fn stylesheet_at(&self, index: usize) -> Option<DomRoot<CSSStyleSheet>> {
+        let stylesheets = &self.author_styles.borrow().stylesheets;
+
+        stylesheets
+            .get(index)
+            .and_then(|s| s.owner.upcast::<Node>().get_cssom_stylesheet())
+    }
+
+    /// Add a stylesheet owned by `owner` to the list of shadow root sheets, in the
+    /// correct tree position.
+    #[allow(unrooted_must_root)] // Owner needs to be rooted already necessarily.
+    pub fn add_stylesheet(&self, owner: &Element, sheet: Arc<Stylesheet>) {
+        let stylesheets = &mut self.author_styles.borrow_mut().stylesheets;
+        let insertion_point = stylesheets
+            .iter()
+            .find(|sheet_in_shadow| {
+                owner
+                    .upcast::<Node>()
+                    .is_before(sheet_in_shadow.owner.upcast())
+            })
+            .cloned();
+        DocumentOrShadowRoot::add_stylesheet(
+            owner,
+            StylesheetSetRef::Author(stylesheets),
+            sheet,
+            insertion_point,
+            self.document.style_shared_lock(),
+        );
+    }
+
+    /// Remove a stylesheet owned by `owner` from the list of shadow root sheets.
+    #[allow(unrooted_must_root)] // Owner needs to be rooted already necessarily.
+    pub fn remove_stylesheet(&self, owner: &Element, s: &Arc<Stylesheet>) {
+        DocumentOrShadowRoot::remove_stylesheet(
+            owner,
+            s,
+            StylesheetSetRef::Author(&mut self.author_styles.borrow_mut().stylesheets),
+        )
+    }
+
+    pub fn invalidate_stylesheets(&self) {
+        self.document.invalidate_shadow_roots_stylesheets();
+        self.author_styles.borrow_mut().stylesheets.force_dirty();
+        // Mark the host element dirty so a reflow will be performed.
+        if let Some(host) = self.host.get() {
+            host.upcast::<Node>().dirty(NodeDamage::NodeStyleDamaged);
+        }
+    }
+
+    /// Remove any existing association between the provided id and any elements
+    /// in this shadow tree.
+    pub fn unregister_element_id(&self, to_unregister: &Element, id: Atom) {
+        self.document_or_shadow_root.unregister_named_element(
+            self.document_fragment.id_map(),
+            to_unregister,
+            &id,
+        );
+    }
+
+    /// Associate an element present in this shadow tree with the provided id.
+    pub fn register_element_id(&self, element: &Element, id: Atom) {
+        let root = self
+            .upcast::<Node>()
+            .inclusive_ancestors(ShadowIncluding::No)
+            .last()
+            .unwrap();
+        self.document_or_shadow_root.register_named_element(
+            self.document_fragment.id_map(),
+            element,
+            &id,
+            root,
+        );
+    }
+}
+
+impl ShadowRootMethods for ShadowRoot {
+    // https://html.spec.whatwg.org/multipage/#dom-document-activeelement
+    fn GetActiveElement(&self) -> Option<DomRoot<Element>> {
+        self.document_or_shadow_root
+            .get_active_element(self.get_focused_element(), None, None)
+    }
+
+    // https://drafts.csswg.org/cssom-view/#dom-document-elementfrompoint
+    fn ElementFromPoint(&self, x: Finite<f64>, y: Finite<f64>) -> Option<DomRoot<Element>> {
+        // Return the result of running the retargeting algorithm with context object
+        // and the original result as input.
+        match self.document_or_shadow_root.element_from_point(
+            x,
+            y,
+            None,
+            self.document.has_browsing_context(),
+        ) {
+            Some(e) => {
+                let retargeted_node = self.upcast::<Node>().retarget(e.upcast::<Node>());
+                retargeted_node
+                    .downcast::<Element>()
+                    .map(|n| DomRoot::from_ref(n))
+            },
+            None => None,
+        }
+    }
+
+    // https://drafts.csswg.org/cssom-view/#dom-document-elementsfrompoint
+    fn ElementsFromPoint(&self, x: Finite<f64>, y: Finite<f64>) -> Vec<DomRoot<Element>> {
+        // Return the result of running the retargeting algorithm with context object
+        // and the original result as input
+        let mut elements = Vec::new();
+        for e in self
+            .document_or_shadow_root
+            .elements_from_point(x, y, None, self.document.has_browsing_context())
+            .iter()
+        {
+            let retargeted_node = self.upcast::<Node>().retarget(e.upcast::<Node>());
+            if let Some(element) = retargeted_node
+                .downcast::<Element>()
+                .map(|n| DomRoot::from_ref(n))
+            {
+                elements.push(element);
+            }
+        }
+        elements
+    }
+
+    /// https://dom.spec.whatwg.org/#dom-shadowroot-mode
+    fn Mode(&self) -> ShadowRootMode {
+        ShadowRootMode::Closed
+    }
+
+    /// https://dom.spec.whatwg.org/#dom-shadowroot-host
+    fn Host(&self) -> DomRoot<Element> {
+        let host = self.host.get();
+        host.expect("Trying to get host from a detached shadow root")
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-document-stylesheets
+    fn StyleSheets(&self) -> DomRoot<StyleSheetList> {
+        self.stylesheet_list.or_init(|| {
+            StyleSheetList::new(
+                &self.window,
+                StyleSheetListOwner::ShadowRoot(Dom::from_ref(self)),
+            )
+        })
+    }
+}
+
+#[allow(unsafe_code)]
+pub trait LayoutShadowRootHelpers<'dom> {
+    fn get_host_for_layout(self) -> LayoutDom<'dom, Element>;
+    fn get_style_data_for_layout(self) -> &'dom CascadeData;
+    unsafe fn flush_stylesheets<E: TElement>(
+        self,
+        device: &Device,
+        quirks_mode: QuirksMode,
+        guard: &SharedRwLockReadGuard,
+    );
+}
+
+impl<'dom> LayoutShadowRootHelpers<'dom> for LayoutDom<'dom, ShadowRoot> {
+    #[inline]
+    #[allow(unsafe_code)]
+    fn get_host_for_layout(self) -> LayoutDom<'dom, Element> {
+        unsafe {
+            self.unsafe_get()
+                .host
+                .get_inner_as_layout()
+                .expect("We should never do layout on a detached shadow root")
+        }
+    }
+
+    #[inline]
+    #[allow(unsafe_code)]
+    fn get_style_data_for_layout(self) -> &'dom CascadeData {
+        fn is_sync<T: Sync>() {}
+        let _ = is_sync::<CascadeData>;
+        unsafe { &self.unsafe_get().author_styles.borrow_for_layout().data }
+    }
+
+    // FIXME(nox): This uses the dreaded borrow_mut_for_layout so this should
+    // probably be revisited.
+    #[inline]
+    #[allow(unsafe_code)]
+    unsafe fn flush_stylesheets<E: TElement>(
+        self,
+        device: &Device,
+        quirks_mode: QuirksMode,
+        guard: &SharedRwLockReadGuard,
+    ) {
+        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);
+        }
+    }
+}