Issue 7720: Add target selector and update when scrolling to fragment

components/script/dom/document.rs

@@ -241,6 +241,8 @@ pub struct Document {
     referrer_policy: Cell<Option<ReferrerPolicy>>,
     /// https://html.spec.whatwg.org/multipage/#dom-document-referrer
     referrer: Option<String>,
+    /// https://html.spec.whatwg.org/multipage/#target-element
+    target_element: MutNullableHeap<JS<Element>>,
 }
 
 #[derive(JSTraceable, HeapSizeOf)]
@@ -1735,6 +1737,7 @@ impl Document {
             origin: origin,
             referrer: referrer,
             referrer_policy: Cell::new(referrer_policy),
+            target_element: MutNullableHeap::new(None),
         }
     }
 
@@ -1886,6 +1889,22 @@ impl Document {
     pub fn get_referrer_policy(&self) -> Option<ReferrerPolicy> {
         return self.referrer_policy.get();
     }
+
+    pub fn set_target_element(&self, node: Option<&Element>) {
+        if let Some(ref element) = self.target_element.get() {
+            element.set_target_state(false);
+        }
+
+        self.target_element.set(node);
+
+        if let Some(ref element) = self.target_element.get() {
+            element.set_target_state(true);
+        }
+
+        self.window.reflow(ReflowGoal::ForDisplay,
+                           ReflowQueryType::NoQuery,
+                           ReflowReason::ElementStateChanged);
+    }
 }
 
 

components/script/dom/element.rs

@@ -2324,7 +2324,8 @@ impl<'a> ::selectors::Element for Root<Element> {
             NonTSPseudoClass::Checked |
             NonTSPseudoClass::Indeterminate |
             NonTSPseudoClass::ReadWrite |
-            NonTSPseudoClass::PlaceholderShown =>
+            NonTSPseudoClass::PlaceholderShown |
+            NonTSPseudoClass::Target =>
                 Element::state(self).contains(pseudo_class.state_flag()),
         }
     }
@@ -2586,6 +2587,14 @@ impl Element {
             self.upcast::<Node>().dirty(NodeDamage::OtherNodeDamage);
         }
     }
+
+    pub fn target_state(&self) -> bool {
+        self.state.get().contains(IN_TARGET_STATE)
+    }
+
+    pub fn set_target_state(&self, value: bool) {
+       self.set_state(IN_TARGET_STATE, value)
+    }
 }
 
 impl Element {

components/script/layout_wrapper.rs

@@ -551,7 +551,8 @@ impl<'le> ::selectors::Element for ServoLayoutElement<'le> {
             NonTSPseudoClass::Checked |
             NonTSPseudoClass::Indeterminate |
             NonTSPseudoClass::ReadWrite |
-            NonTSPseudoClass::PlaceholderShown =>
+            NonTSPseudoClass::PlaceholderShown |
+            NonTSPseudoClass::Target =>
                 self.element.get_state_for_layout().contains(pseudo_class.state_flag())
         }
     }

components/script/script_thread.rs

@@ -1198,6 +1198,22 @@ impl ScriptThread {
         // https://html.spec.whatwg.org/multipage/#the-end step 7
         let handler = box DocumentProgressHandler::new(Trusted::new(doc));
         self.dom_manipulation_task_source.queue(handler, GlobalRef::Window(doc.window())).unwrap();
+
+        if let Some(fragment) = doc.url().fragment() {
+            self.check_and_scroll_fragment(fragment, pipeline, doc);
+        }
+    }
+
+    fn check_and_scroll_fragment(&self, fragment: &str, pipeline_id: PipelineId, doc: &Document) {
+        match doc.find_fragment_node(fragment) {
+            Some(ref node) => {
+                doc.set_target_element(Some(node.r()));
+                self.scroll_fragment_point(pipeline_id, node.r());
+            }
+            None => {
+                doc.set_target_element(None);
+            }
+        }
     }
 
     fn collect_reports(&self, reports_chan: ReportsChan) {
@@ -1996,7 +2012,7 @@ impl ScriptThread {
     /// The entry point for content to notify that a new load has been requested
     /// for the given pipeline (specifically the "navigate" algorithm).
     fn handle_navigate(&self, pipeline_id: PipelineId, subpage_id: Option<SubpageId>, load_data: LoadData) {
-        // Step 8.
+        // Step 7.
         {
             let nurl = &load_data.url;
             if let Some(fragment) = nurl.fragment() {
@@ -2007,12 +2023,7 @@ impl ScriptThread {
                 let url = document.url();
                 if &url[..Position::AfterQuery] == &nurl[..Position::AfterQuery] &&
                     load_data.method == Method::Get {
-                    match document.find_fragment_node(fragment) {
-                        Some(ref node) => {
-                            self.scroll_fragment_point(pipeline_id, node.r());
-                        }
-                        None => {}
-                    }
+                    self.check_and_scroll_fragment(fragment, pipeline_id, document.r());
                     return;
                 }
             }