From 828b10cc337784444b18e4c178a75f87c771412a Mon Sep 17 00:00:00 2001
From: Richard Qin <richard.qin.x@gmail.com>
Date: Sat, 11 Apr 2026 03:26:17 +0800
Subject: feat: implement DOM tree builder to transform HTML tokens into a
 hierarchical structure

---
 src/parser/tree_builder.cc | 90 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 src/parser/tree_builder.cc

(limited to 'src/parser/tree_builder.cc')

diff --git a/src/parser/tree_builder.cc b/src/parser/tree_builder.cc
new file mode 100644
index 0000000..51a8a51
--- /dev/null
+++ b/src/parser/tree_builder.cc
@@ -0,0 +1,90 @@
+/*
+ * Ricochet - A minimalist CLI web browser for fast, distraction-free navigation.
+ * Copyright (C) 2026  Richard Qin
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "ricochet/parser/tree_builder.hh"
+#include "ricochet/parser/dom_tree.hh"
+#include <utility>
+#include <vector>
+
+namespace ricochet::parser {
+
+namespace {
+struct TokenVisitor {
+    std::vector<DomNode>* stack;
+
+    void operator()(const TextToken& token) const {
+        stack->back().children.emplace_back(
+            DomNode{
+                .tag_name = "",
+                .text_content = token.content, 
+                .children = {}
+            }
+        );
+    }
+
+    void operator()(const TagOpenToken& token) const {
+        DomNode new_node{
+            .tag_name = token.name, 
+            .text_content = "", 
+            .children = {}
+        };
+
+        if (token.name == "meta" || token.name == "link" || token.name == "img" || 
+            token.name == "br" || token.name == "hr" || token.name == "input" || 
+            token.name == "base" || token.name == "col") {
+            
+            stack->back().children.push_back(std::move(new_node));
+        } else {
+            stack->push_back(std::move(new_node));
+        }
+    }
+
+    void operator()(const TagCloseToken& /*token*/) const {
+        if (stack->size() > 1) {
+            DomNode completed_node = std::move(stack->back());
+            stack->pop_back();
+            stack->back().children.push_back(std::move(completed_node));
+        }
+    }
+};
+} // namespace
+
+DomNode TreeBuilder::build(const std::vector<HtmlToken>& tokens) const // NOLINT(readability-convert-member-functions-to-static)
+{
+    std::vector<DomNode> stack;
+    stack.emplace_back(DomNode{
+        .tag_name = "Document",
+        .text_content = "",
+        .children = {}
+    });
+
+    TokenVisitor visitor{&stack};
+    for (const auto& token : tokens) {
+        std::visit(visitor, token);
+    }
+
+    while (stack.size() > 1) {
+        DomNode completed_node = std::move(stack.back());
+        stack.pop_back();
+        stack.back().children.push_back(std::move(completed_node));
+    }
+
+    return std::move(stack.front());
+}
+
+} // namespace ricochet::parser
\ No newline at end of file
-- 
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