LibWeb: Support :active pseudo-class for hyperlinks, :focus possibly

Adds support for the :active pseudo-class for hyperlinks (<a> tags
only).

Also, since it was very similar to :focus and an element having a
focused state was already implemented, I went ahead and implemented
that pseudo-class too, although I cannot come up with a working
example to validate it.

Userland/Libraries/LibWeb/CSS/Parser/DeprecatedCSSParser.cpp

@@ -563,6 +563,8 @@ public:
                 simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::Link;
             } else if (pseudo_name.equals_ignoring_case("visited")) {
                 simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::Visited;
+            } else if (pseudo_name.equals_ignoring_case("active")) {
+                simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::Active;
             } else if (pseudo_name.equals_ignoring_case("hover")) {
                 simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::Hover;
             } else if (pseudo_name.equals_ignoring_case("focus")) {

Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp

@@ -200,6 +200,8 @@ Vector<CSS::Selector::ComplexSelector> Parser::parse_selectors(Vector<String> pa
                 simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::Link;
             } else if (pseudo_name.equals_ignoring_case("visited")) {
                 simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::Visited;
+            } else if (pseudo_name.equals_ignoring_case("active")) {
+                simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::Active;
             } else if (pseudo_name.equals_ignoring_case("hover")) {
                 simple_selector.pseudo_class = CSS::Selector::SimpleSelector::PseudoClass::Hover;
             } else if (pseudo_name.equals_ignoring_case("focus")) {

Userland/Libraries/LibWeb/CSS/Selector.h

@@ -43,6 +43,7 @@ public:
             Enabled,
             Checked,
             Not,
+            Active,
         };
         PseudoClass pseudo_class { PseudoClass::None };
 

Userland/Libraries/LibWeb/CSS/SelectorEngine.cpp

@@ -44,13 +44,18 @@ static bool matches(const CSS::Selector::SimpleSelector& component, const DOM::E
     case CSS::Selector::SimpleSelector::PseudoClass::Visited:
         // FIXME: Maybe match this selector sometimes?
         return false;
+    case CSS::Selector::SimpleSelector::PseudoClass::Active:
+        if (!element.is_active())
+            return false;
+        break;
     case CSS::Selector::SimpleSelector::PseudoClass::Hover:
         if (!matches_hover_pseudo_class(element))
             return false;
         break;
     case CSS::Selector::SimpleSelector::PseudoClass::Focus:
-        // FIXME: Implement matches_focus_pseudo_class(element)
+        if (!element.is_focused())
             return false;
+        break;
     case CSS::Selector::SimpleSelector::PseudoClass::FirstChild:
         if (element.previous_element_sibling())
             return false;

Userland/Libraries/LibWeb/DOM/Document.cpp

@@ -876,6 +876,17 @@ void Document::set_focused_element(Element* element)
         m_layout_root->set_needs_display();
 }
 
+void Document::set_active_element(Element* element)
+{
+    if (m_active_element == element)
+        return;
+
+    m_active_element = element;
+
+    if (m_layout_root)
+        m_layout_root->set_needs_display();
+}
+
 void Document::set_ready_state(const String& ready_state)
 {
     m_ready_state = ready_state;

Userland/Libraries/LibWeb/DOM/Document.h

@@ -208,6 +208,10 @@ public:
 
     void set_focused_element(Element*);
 
+    const Element* active_element() const { return m_active_element; }
+
+    void set_active_element(Element*);
+
     bool created_for_appropriate_template_contents() const { return m_created_for_appropriate_template_contents; }
     void set_created_for_appropriate_template_contents(bool value) { m_created_for_appropriate_template_contents = value; }
 
@@ -323,6 +327,7 @@ private:
     bool m_editable { false };
 
     WeakPtr<Element> m_focused_element;
+    WeakPtr<Element> m_active_element;
 
     bool m_created_for_appropriate_template_contents { false };
     RefPtr<Document> m_associated_inert_template_document;

Userland/Libraries/LibWeb/DOM/Element.cpp

@@ -327,6 +327,11 @@ bool Element::is_focused() const
     return document().focused_element() == this;
 }
 
+bool Element::is_active() const
+{
+    return document().active_element() == this;
+}
+
 NonnullRefPtr<HTMLCollection> Element::get_elements_by_tag_name(FlyString const& tag_name)
 {
     // FIXME: Support "*" for tag_name

Userland/Libraries/LibWeb/DOM/Element.h

@@ -86,6 +86,8 @@ public:
     bool is_focused() const;
     virtual bool is_focusable() const { return false; }
 
+    bool is_active() const;
+
     NonnullRefPtr<HTMLCollection> get_elements_by_tag_name(FlyString const&);
     NonnullRefPtr<HTMLCollection> get_elements_by_class_name(FlyString const&);
 

Userland/Libraries/LibWeb/Dump.cpp

@@ -341,6 +341,9 @@ void dump_selector(StringBuilder& builder, const CSS::Selector& selector)
             case CSS::Selector::SimpleSelector::PseudoClass::Visited:
                 pseudo_class_description = "Visited";
                 break;
+            case CSS::Selector::SimpleSelector::PseudoClass::Active:
+                pseudo_class_description = "Active";
+                break;
             case CSS::Selector::SimpleSelector::PseudoClass::None:
                 pseudo_class_description = "None";
                 break;

Userland/Libraries/LibWeb/Page/EventHandler.cpp

@@ -237,6 +237,7 @@ bool EventHandler::handle_mousedown(const Gfx::IntPoint& position, unsigned butt
                 auto anchor = href.substring_view(1, href.length() - 1);
                 m_frame.scroll_to_anchor(anchor);
             } else {
+                document->set_active_element(link);
                 if (m_frame.is_top_level()) {
                     if (auto* page = m_frame.page())
                         page->client().page_did_click_link(url, link->target(), modifiers);