Auto merge of #22771 - MaT1g3R:refactor_follow_hyperlink, r=jdm

Refactor follow_hyperlink and its callers

Now they follow the new spec stated at:
https://html.spec.whatwg.org/multipage/links.html#following-hyperlinks-2

It seems like choosing a browsing context is already done in the
follow_hyperlink method, so I have removed the TODO in
activation_behavior for HTMLAreaElement.

The tests in `tests/wpt/web-platform-tests/html/semantics/links/following-hyperlinks/`
pass in release builds, but still don't pass in dev build,
since the timeout in
`tests/wpt/web-platform-tests/html/semantics/links/following-hyperlinks/activation-behavior.window.js`
seems to be too short for dev builds.

Navigating to error page on failed URL parsing is still not implemented.

There seem to be potential code duplication in activation_behavior
methods for both htmlanchorelement.rs and htmlareaelement.rs, in:

    let referrer_policy = match self.RelList().Contains("noreferrer".into()) {
        true => Some(ReferrerPolicy::NoReferrer),
        false => None,
    };

I didn't pull them out to a separate function since I don't know
where I would put that new function.

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- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #22761 (GitHub issue number if applicable)

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1 files changed, 23 insertions, 28 deletions

diff --git a/components/script/dom/htmlanchorelement.rs b/components/script/dom/htmlanchorelement.rs
index e024fb6a00a..3f078c51071 100644
--- a/components/script/dom/htmlanchorelement.rs
+++ b/components/script/dom/htmlanchorelement.rs
@@ -3,9 +3,9 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use crate::dom::activation::Activatable;
+use crate::dom::attr::Attr;
 use crate::dom::bindings::cell::DomRefCell;
 use crate::dom::bindings::codegen::Bindings::AttrBinding::AttrMethods;
-use crate::dom::bindings::codegen::Bindings::DOMTokenListBinding::DOMTokenListMethods;
 use crate::dom::bindings::codegen::Bindings::HTMLAnchorElementBinding;
 use crate::dom::bindings::codegen::Bindings::HTMLAnchorElementBinding::HTMLAnchorElementMethods;
 use crate::dom::bindings::codegen::Bindings::MouseEventBinding::MouseEventMethods;
@@ -13,6 +13,7 @@ use crate::dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use crate::dom::bindings::inheritance::Castable;
 use crate::dom::bindings::root::{DomRoot, MutNullableDom};
 use crate::dom::bindings::str::{DOMString, USVString};
+use crate::dom::document::determine_policy_for_token;
 use crate::dom::document::Document;
 use crate::dom::domtokenlist::DOMTokenList;
 use crate::dom::element::Element;
@@ -26,7 +27,6 @@ use crate::dom::urlhelper::UrlHelper;
 use crate::dom::virtualmethods::VirtualMethods;
 use dom_struct::dom_struct;
 use html5ever::{LocalName, Prefix};
-use net_traits::ReferrerPolicy;
 use num_traits::ToPrimitive;
 use servo_url::ServoUrl;
 use std::default::Default;
@@ -541,7 +541,7 @@ impl Activatable for HTMLAnchorElement {
         // hyperlink"
         // https://html.spec.whatwg.org/multipage/#the-a-element
         // "The activation behaviour of a elements *that create hyperlinks*"
-        self.upcast::<Element>().has_attribute(&local_name!("href"))
+        self.as_element().has_attribute(&local_name!("href"))
     }
 
     //TODO:https://html.spec.whatwg.org/multipage/#the-a-element
@@ -553,16 +553,12 @@ impl Activatable for HTMLAnchorElement {
 
     //https://html.spec.whatwg.org/multipage/#the-a-element:activation-behaviour
     fn activation_behavior(&self, event: &Event, target: &EventTarget) {
-        //Step 1. If the node document is not fully active, abort.
-        let doc = document_from_node(self);
-        if !doc.is_fully_active() {
-            return;
-        }
-        //TODO: Step 2. Check if browsing context is specified and act accordingly.
-        //Step 3. Handle <img ismap/>.
-        let element = self.upcast::<Element>();
+        let element = self.as_element();
         let mouse_event = event.downcast::<MouseEvent>().unwrap();
         let mut ismap_suffix = None;
+
+        // Step 1: If the target of the click event is an img element with an ismap attribute
+        // specified, then server-side image map processing must be performed.
         if let Some(element) = target.downcast::<Element>() {
             if target.is::<HTMLImageElement>() && element.has_attribute(&local_name!("ismap")) {
                 let target_node = element.upcast::<Node>();
@@ -575,16 +571,9 @@ impl Activatable for HTMLAnchorElement {
             }
         }
 
-        // Step 4.
+        // Step 2.
         //TODO: Download the link is `download` attribute is set.
-
-        // https://w3c.github.io/webappsec-referrer-policy/#referrer-policy-delivery
-        let referrer_policy = match self.RelList().Contains("noreferrer".into()) {
-            true => Some(ReferrerPolicy::NoReferrer),
-            false => None,
-        };
-
-        follow_hyperlink(element, ismap_suffix, referrer_policy);
+        follow_hyperlink(element, ismap_suffix);
     }
 
     //TODO:https://html.spec.whatwg.org/multipage/#the-a-element
@@ -599,12 +588,11 @@ impl Activatable for HTMLAnchorElement {
 }
 
 /// <https://html.spec.whatwg.org/multipage/#following-hyperlinks-2>
-pub fn follow_hyperlink(
-    subject: &Element,
-    hyperlink_suffix: Option<String>,
-    referrer_policy: Option<ReferrerPolicy>,
-) {
-    // Step 1: TODO: If subject cannot navigate, then return.
+pub fn follow_hyperlink(subject: &Element, hyperlink_suffix: Option<String>) {
+    // Step 1.
+    if subject.cannot_navigate() {
+        return;
+    }
     // Step 2, done in Step 7.
 
     let document = document_from_node(subject);
@@ -631,13 +619,15 @@ pub fn follow_hyperlink(
         Some(name) => source.choose_browsing_context(name.Value(), noopener),
         None => (Some(window.window_proxy()), false),
     };
+
+    // Step 8.
     let chosen = match maybe_chosen {
         Some(proxy) => proxy,
         None => return,
     };
+
     if let Some(target_document) = chosen.document() {
         let target_window = target_document.window();
-
         // Step 9, dis-owning target's opener, if necessary
         // will have been done as part of Step 7 above
         // in choose_browsing_context/create_auxiliary_browsing_context.
@@ -645,7 +635,7 @@ pub fn follow_hyperlink(
         // Step 10, 11, 12, 13. TODO: if parsing the URL failed, navigate to error page.
         let attribute = subject.get_attribute(&ns!(), &local_name!("href")).unwrap();
         let mut href = attribute.Value();
-        // Step 12: append a hyperlink suffix.
+        // Step 11: append a hyperlink suffix.
         // https://www.w3.org/Bugs/Public/show_bug.cgi?id=28925
         if let Some(suffix) = hyperlink_suffix {
             href.push_str(&suffix);
@@ -655,6 +645,11 @@ pub fn follow_hyperlink(
             Err(_) => return,
         };
 
+        // Step 12.
+        let referrer_policy = subject
+            .get_attribute_by_name(DOMString::from_string(String::from("referrerpolicy")))
+            .and_then(|attribute: DomRoot<Attr>| (determine_policy_for_token(&attribute.Value())));
+
         // Step 13, 14.
         debug!("following hyperlink to {}", url);
         target_window.load_url(url, replace, false, referrer_policy);