LibHTML: Start building the style tree.

Walk the DOM and construct a parallel style tree that points back to the DOM
and has the relevant CSS property values hanging off of them.

The values are picked based on naive selector matching. There's no cascade
or specificity taken into account yet.

LibHTML/CSS/StyleResolver.cpp

@@ -1,5 +1,7 @@
 #include <LibHTML/CSS/StyleResolver.h>
 #include <LibHTML/CSS/StyleSheet.h>
+#include <LibHTML/CSS/StyledNode.h>
+#include <LibHTML/DOM/Document.h>
 #include <LibHTML/DOM/Element.h>
 #include <LibHTML/Dump.h>
 #include <stdio.h>
@@ -51,15 +53,19 @@ NonnullRefPtrVector<StyleRule> StyleResolver::collect_matching_rules(const Eleme
     return matching_rules;
 }
 
-OwnPtr<LayoutStyle> StyleResolver::resolve_document_style(const Document& document)
+NonnullRefPtr<StyledNode> StyleResolver::create_styled_node(const Document& document)
 {
-    UNUSED_PARAM(document);
-    return make<LayoutStyle>();
+    return StyledNode::create(document);
 }
 
-OwnPtr<LayoutStyle> StyleResolver::resolve_element_style(const Element& element)
+NonnullRefPtr<StyledNode> StyleResolver::create_styled_node(const Element& element)
 {
-    auto style = make<LayoutStyle>();
+    auto style = StyledNode::create(element);
     auto matching_rules = collect_matching_rules(element);
+    for (auto& rule : matching_rules) {
+        for (auto& declaration : rule.declarations()) {
+            style->set_property(declaration.property_name(), declaration.value());
+        }
+    }
     return style;
 }

LibHTML/CSS/StyleResolver.h

@@ -2,12 +2,13 @@
 
 #include <AK/OwnPtr.h>
 #include <AK/NonnullRefPtrVector.h>
-#include <LibHTML/Layout/LayoutStyle.h>
 
 class Document;
 class Element;
+class ParentNode;
 class StyleRule;
 class StyleSheet;
+class StyledNode;
 
 class StyleResolver {
 public:
@@ -19,8 +20,8 @@ public:
 
     void add_sheet(const StyleSheet& sheet) { m_sheets.append(sheet); }
 
-    OwnPtr<LayoutStyle> resolve_element_style(const Element&);
-    OwnPtr<LayoutStyle> resolve_document_style(const Document&);
+    NonnullRefPtr<StyledNode> create_styled_node(const Element&);
+    NonnullRefPtr<StyledNode> create_styled_node(const Document&);
 
     NonnullRefPtrVector<StyleRule> collect_matching_rules(const Element&) const;
 

LibHTML/CSS/StyledNode.h

@@ -10,6 +10,10 @@ class Node;
 
 class StyledNode : public TreeNode<StyledNode> {
 public:
+    static NonnullRefPtr<StyledNode> create(const Node& node)
+    {
+        return adopt(*new StyledNode(&node));
+    }
     ~StyledNode();
 
     const Node* node() const { return m_node; }
@@ -28,6 +32,18 @@ public:
             callback(*node);
     }
 
+    template<typename Callback>
+    inline void for_each_property(Callback callback) const
+    {
+        for (auto& it : m_property_values)
+            callback(it.key, *it.value);
+    }
+
+    void set_property(const String& name, NonnullRefPtr<StyleValue> value)
+    {
+        m_property_values.set(name, move(value));
+    }
+
 protected:
     explicit StyledNode(const Node*);
 

LibHTML/Dump.cpp

@@ -1,4 +1,5 @@
 #include <LibHTML/CSS/StyleSheet.h>
+#include <LibHTML/CSS/StyledNode.h>
 #include <LibHTML/DOM/Document.h>
 #include <LibHTML/DOM/Element.h>
 #include <LibHTML/DOM/Text.h>
@@ -67,6 +68,38 @@ void dump_tree(const LayoutNode& layout_node)
     --indent;
 }
 
+void dump_tree(const StyledNode& styled_node)
+{
+    static int indent = 0;
+    for (int i = 0; i < indent; ++i)
+        printf("    ");
+
+    String tag_name;
+    auto& node = *styled_node.node();
+    if (node.is_text())
+        tag_name = "#text";
+    else if (node.is_document())
+        tag_name = "#document";
+    else if (node.is_element())
+        tag_name = static_cast<const Element&>(node).tag_name();
+    else
+        tag_name = "???";
+
+    printf("%s", tag_name.characters());
+    printf("\n");
+
+    styled_node.for_each_property([&](auto& key, auto& value) {
+        for (int i = 0; i < indent; ++i)
+            printf("    ");
+        printf("  (%s: %s)\n", key.characters(), value.to_string().characters());
+    });
+    ++indent;
+    styled_node.for_each_child([](auto& child) {
+        dump_tree(child);
+    });
+    --indent;
+}
+
 void dump_rule(const StyleRule& rule)
 {
     printf("Rule:\n");

LibHTML/Dump.h

@@ -4,8 +4,10 @@ class Node;
 class LayoutNode;
 class StyleRule;
 class StyleSheet;
+class StyledNode;
 
 void dump_tree(const Node&);
+void dump_tree(const StyledNode&);
 void dump_tree(const LayoutNode&);
 void dump_sheet(const StyleSheet&);
 void dump_rule(const StyleRule&);

LibHTML/test.cpp

@@ -3,6 +3,7 @@
 #include <LibHTML/Frame.h>
 #include <LibHTML/Parser/CSSParser.h>
 #include <LibHTML/CSS/StyleResolver.h>
+#include <LibHTML/CSS/StyledNode.h>
 #include <LibHTML/DOM/Element.h>
 #include <LibHTML/Parser/HTMLParser.h>
 #include <stdio.h>
@@ -28,18 +29,29 @@ int main(int argc, char** argv)
     StyleResolver resolver(*doc);
     resolver.add_sheet(*sheet);
 
-    auto doc_style = resolver.resolve_document_style(*doc);
-
-    Function<void(const ParentNode&)> resolve_style = [&](const ParentNode& node) {
-        node.for_each_child([&](const Node& child) {
+    Function<RefPtr<StyledNode>(const Node&, StyledNode*)> resolve_style = [&](const Node& node, StyledNode* parent_styled_node) -> RefPtr<StyledNode> {
+        auto styled_node = [&]() -> RefPtr<StyledNode> {
+            if (node.is_element())
+                return resolver.create_styled_node(static_cast<const Element&>(node));
+            if (node.is_document())
+                return resolver.create_styled_node(static_cast<const Document&>(node));
+            return nullptr;
+        }();
+        if (!styled_node)
+            return nullptr;
+        if (parent_styled_node)
+            parent_styled_node->append_child(*styled_node);
+        static_cast<const ParentNode&>(node).for_each_child([&](const Node& child) {
             if (!child.is_element())
                 return;
-            auto style = resolver.resolve_element_style(static_cast<const Element&>(node));
-            printf("Resolved LayoutStyle{%p} for Element{%p}\n", style.ptr(), &node);
-            resolve_style(static_cast<const Element&>(child));
+            auto styled_child_node = resolve_style(static_cast<const Element&>(child), styled_node.ptr());
+            printf("Created StyledNode{%p} for Element{%p}\n", styled_child_node.ptr(), &node);
         });
+        return styled_node;
     };
-    resolve_style(*doc);
+    auto styled_root = resolve_style(*doc, nullptr);
+
+    dump_tree(*styled_root);
 
     doc->build_layout_tree();
     ASSERT(doc->layout_node());