LibHTML: Detect hovering over links

HtmlView now calls Node::enclosing_link_element() to find the nearest
ancestor <a> element.

This patch also adds HTMLElement and HTMLAnchorElement.

Libraries/LibHTML/DOM/HTMLAnchorElement.cpp

@@ -0,0 +1,10 @@
+#include <LibHTML/DOM/HTMLAnchorElement.h>
+
+HTMLAnchorElement::HTMLAnchorElement(Document& document, const String& tag_name)
+    : HTMLElement(document, tag_name)
+{
+}
+
+HTMLAnchorElement::~HTMLAnchorElement()
+{
+}

Libraries/LibHTML/DOM/HTMLAnchorElement.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <LibHTML/DOM/HTMLElement.h>
+
+class HTMLAnchorElement : public HTMLElement {
+public:
+    HTMLAnchorElement(Document&, const String& tag_name);
+    virtual ~HTMLAnchorElement() override;
+
+    String href() const { return attribute("href"); }
+};

Libraries/LibHTML/DOM/HTMLElement.cpp

@@ -0,0 +1,10 @@
+#include <LibHTML/DOM/HTMLElement.h>
+
+HTMLElement::HTMLElement(Document& document, const String& tag_name)
+    : Element(document, tag_name)
+{
+}
+
+HTMLElement::~HTMLElement()
+{
+}

Libraries/LibHTML/DOM/HTMLElement.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <LibHTML/DOM/Element.h>
+
+class HTMLElement : public Element {
+public:
+    HTMLElement(Document&, const String& tag_name);
+    virtual ~HTMLElement() override;
+};

Libraries/LibHTML/DOM/Node.cpp

@@ -1,5 +1,6 @@
 #include <LibHTML/DOM/Node.h>
 #include <LibHTML/DOM/Element.h>
+#include <LibHTML/DOM/HTMLAnchorElement.h>
 #include <LibHTML/CSS/StyleResolver.h>
 #include <LibHTML/Layout/LayoutNode.h>
 #include <LibHTML/Layout/LayoutBlock.h>
@@ -73,3 +74,10 @@ RefPtr<LayoutNode> Node::create_layout_tree(const StyleResolver& resolver, const
         }
     return layout_node;
 }
+
+const HTMLAnchorElement* Node::enclosing_link_element() const
+{
+    if (is_element() && tag_name().to_lowercase() == "a")
+        return static_cast<const HTMLAnchorElement*>(this);
+    return parent() ? parent()->enclosing_link_element() : nullptr;
+}

Libraries/LibHTML/DOM/Node.h

@@ -14,6 +14,7 @@ enum class NodeType : unsigned {
 };
 
 class Document;
+class HTMLAnchorElement;
 class ParentNode;
 class LayoutNode;
 class StyleResolver;
@@ -37,6 +38,8 @@ public:
     Document& document() { return m_document; }
     const Document& document() const { return m_document; }
 
+    const HTMLAnchorElement* enclosing_link_element() const;
+
 protected:
     Node(Document&, NodeType);
 

Libraries/LibHTML/HtmlView.cpp

@@ -1,6 +1,7 @@
 #include <LibGUI/GPainter.h>
 #include <LibGUI/GScrollBar.h>
 #include <LibHTML/DOM/Element.h>
+#include <LibHTML/DOM/HTMLAnchorElement.h>
 #include <LibHTML/Dump.h>
 #include <LibHTML/HtmlView.h>
 #include <LibHTML/Layout/LayoutNode.h>
@@ -93,6 +94,9 @@ void HtmlView::mousemove_event(GMouseEvent& event)
         hovered_node_changed = node == m_document->hovered_node();
         if (node) {
             dbg() << "HtmlView: mousemove: " << node->tag_name() << "{" << node << "}";
+            if (auto* link = node->enclosing_link_element()) {
+                dbg() << "HtmlView: hovering over a link to " << link->href();
+            }
         }
     }
     if (hovered_node_changed)

Libraries/LibHTML/Makefile.shared

@@ -2,6 +2,8 @@ LIBHTML_OBJS = \
     DOM/Node.o \
     DOM/ParentNode.o \
     DOM/Element.o \
+    DOM/HTMLElement.o \
+    DOM/HTMLAnchorElement.o \
     DOM/Document.o \
     DOM/Text.o \
     CSS/Selector.o \

Libraries/LibHTML/Parser/HTMLParser.cpp

@@ -1,6 +1,7 @@
 #include <AK/NonnullRefPtrVector.h>
 #include <AK/StringBuilder.h>
 #include <LibHTML/DOM/Element.h>
+#include <LibHTML/DOM/HTMLAnchorElement.h>
 #include <LibHTML/DOM/Text.h>
 #include <LibHTML/Parser/HTMLParser.h>
 #include <ctype.h>
@@ -8,6 +9,8 @@
 
 static NonnullRefPtr<Element> create_element(Document& document, const String& tag_name)
 {
+    if (tag_name.to_lowercase() == "a")
+        return adopt(*new HTMLAnchorElement(document, tag_name));
     return adopt(*new Element(document, tag_name));
 }