LibManual: Refactor SectionNode in preparation for subsections

- Calculate the full name on demand
- Make section and name protected
- Reorder some members logically
- Change the name getter to be fallible, as some implementors need to
  allocate

Userland/Applications/Help/MainWidget.cpp

@@ -307,6 +307,7 @@ void MainWidget::open_page(Optional<String> const& path)
         m_web_view->load_empty_document();
         return;
     }
+    dbgln("open page: {}", path.value());
     open_url(URL::create_with_url_or_path(path.value().to_deprecated_string()));
 }
 

Userland/Applications/Help/ManualModel.cpp

@@ -47,7 +47,10 @@ Optional<String> ManualModel::page_name(const GUI::ModelIndex& index) const
     if (!node->is_page())
         return {};
     auto* page = static_cast<Manual::PageNode const*>(node);
-    return page->name();
+    auto path = page->name();
+    if (path.is_error())
+        return {};
+    return path.release_value();
 }
 
 Optional<String> ManualModel::page_path(const GUI::ModelIndex& index) const
@@ -159,7 +162,9 @@ GUI::Variant ManualModel::data(const GUI::ModelIndex& index, GUI::ModelRole role
                 return DeprecatedString(page.release_value());
         return {};
     case GUI::ModelRole::Display:
-        return node->name();
+        if (auto name = node->name(); !name.is_error())
+            return name.release_value();
+        return {};
     case GUI::ModelRole::Icon:
         if (node->is_page())
             return m_page_icon;

Userland/Libraries/LibManual/Node.h

@@ -22,7 +22,7 @@ public:
 
     virtual NonnullRefPtrVector<Node>& children() const = 0;
     virtual Node const* parent() const = 0;
-    virtual String name() const = 0;
+    virtual ErrorOr<String> name() const = 0;
     virtual bool is_page() const { return false; }
     virtual bool is_open() const { return false; }
 };

Userland/Libraries/LibManual/PageNode.h

@@ -25,7 +25,7 @@ public:
 
     virtual NonnullRefPtrVector<Node>& children() const override;
     virtual Node const* parent() const override;
-    virtual String name() const override { return m_page; };
+    virtual ErrorOr<String> name() const override { return m_page; };
     virtual bool is_page() const override { return true; }
 
     ErrorOr<String> path() const;

Userland/Libraries/LibManual/SectionNode.cpp

@@ -17,6 +17,11 @@ ErrorOr<String> SectionNode::path() const
     return String::formatted("/usr/share/man/man{}", m_section);
 }
 
+ErrorOr<String> SectionNode::name() const
+{
+    return String::formatted("{}. {}", m_section, m_name);
+}
+
 ErrorOr<void> SectionNode::reify_if_needed() const
 {
     if (m_reified)

Userland/Libraries/LibManual/SectionNode.h

@@ -19,7 +19,7 @@ public:
 
     SectionNode(StringView section, StringView name)
         : m_section(MUST(String::from_utf8(section)))
-        , m_full_name(MUST(String::formatted("{}. {}", section, name)))
+        , m_name(MUST(String::from_utf8(name)))
     {
     }
 
@@ -30,18 +30,20 @@ public:
     }
 
     virtual Node const* parent() const override { return nullptr; }
-    virtual String name() const override { return m_full_name; }
+    virtual ErrorOr<String> name() const override;
+    String const& section_name() const { return m_section; }
+    ErrorOr<String> path() const;
+
     virtual bool is_open() const override { return m_open; }
     void set_open(bool open);
 
-    String const& section_name() const { return m_section; }
-    ErrorOr<String> path() const;
+protected:
+    String m_section;
+    String m_name;
 
 private:
     ErrorOr<void> reify_if_needed() const;
 
-    String m_section;
-    String m_full_name;
     mutable NonnullRefPtrVector<Node> m_children;
     mutable bool m_reified { false };
     bool m_open { false };