From 5d332c1f11b06328cf45cc0e4bbbd220b0a4c974 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sun, 24 May 2020 20:36:43 +0200
Subject: [PATCH] LibWeb: Parse enough to handle a <style> inside a <head> :^)

---
 .../LibWeb/Parser/HTMLDocumentParser.cpp      | 13 +++
 Libraries/LibWeb/Parser/HTMLDocumentParser.h  |  2 +
 Libraries/LibWeb/Parser/HTMLTokenizer.cpp     | 88 +++++++++++++++++++
 3 files changed, 103 insertions(+)
diff --git a/Libraries/LibWeb/Parser/HTMLDocumentParser.cpp b/Libraries/LibWeb/Parser/HTMLDocumentParser.cpp
index 51088e300f..84be5dd5e0 100644
--- a/Libraries/LibWeb/Parser/HTMLDocumentParser.cpp
+++ b/Libraries/LibWeb/Parser/HTMLDocumentParser.cpp
@@ -207,6 +207,11 @@ void HTMLDocumentParser::handle_in_head(HTMLToken& token)
         return;
     }
 
+    if (token.is_start_tag() && ((token.tag_name() == "noscript" && m_scripting_enabled) || token.tag_name() == "noframes" || token.tag_name() == "style")) {
+        parse_generic_raw_text_element(token);
+        return;
+    }
+
     if (token.is_start_tag() && token.tag_name() == "meta") {
         auto element = insert_html_element(token);
         m_stack_of_open_elements.pop();
@@ -228,6 +233,14 @@ void HTMLDocumentParser::handle_in_head_noscript(HTMLToken&)
     ASSERT_NOT_REACHED();
 }
 
+void HTMLDocumentParser::parse_generic_raw_text_element(HTMLToken& token)
+{
+    insert_html_element(token);
+    m_tokenizer.switch_to({}, HTMLTokenizer::State::RAWTEXT);
+    m_original_insertion_mode = m_insertion_mode;
+    m_insertion_mode = InsertionMode::Text;
+}
+
 void HTMLDocumentParser::insert_character(u32 data)
 {
     auto adjusted_insertion_location = find_appropriate_place_for_inserting_node();
diff --git a/Libraries/LibWeb/Parser/HTMLDocumentParser.h b/Libraries/LibWeb/Parser/HTMLDocumentParser.h
index f74d018876..437e6c1cc8 100644
--- a/Libraries/LibWeb/Parser/HTMLDocumentParser.h
+++ b/Libraries/LibWeb/Parser/HTMLDocumentParser.h
@@ -99,6 +99,7 @@ private:
     void insert_comment(HTMLToken&);
     void reconstruct_the_active_formatting_elements();
     void process_using_the_rules_for(InsertionMode, HTMLToken&);
+    void parse_generic_raw_text_element(HTMLToken&);
 
     InsertionMode m_insertion_mode { InsertionMode::Initial };
     InsertionMode m_original_insertion_mode { InsertionMode::Initial };
@@ -112,6 +113,7 @@ private:
     bool m_foster_parenting { false };
     bool m_frameset_ok { true };
     bool m_parsing_fragment { false };
+    bool m_scripting_enabled { true };
 
     RefPtr<Document> m_document;
     RefPtr<HTMLHeadElement> m_head_element;
diff --git a/Libraries/LibWeb/Parser/HTMLTokenizer.cpp b/Libraries/LibWeb/Parser/HTMLTokenizer.cpp
index a364fc8af6..98d6948cb5 100644
--- a/Libraries/LibWeb/Parser/HTMLTokenizer.cpp
+++ b/Libraries/LibWeb/Parser/HTMLTokenizer.cpp
@@ -827,6 +827,94 @@ Optional<HTMLToken> HTMLTokenizer::next_token()
             }
             END_STATE
 
+            BEGIN_STATE(RAWTEXT)
+            {
+                ON('<')
+                {
+                    SWITCH_TO(RAWTEXTLessThanSign);
+                }
+                ON(0)
+                {
+                    TODO();
+                }
+                ON_EOF
+                {
+                    EMIT_EOF;
+                }
+                ANYTHING_ELSE
+                {
+                    EMIT_CURRENT_CHARACTER;
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(RAWTEXTLessThanSign)
+            {
+                ON('/')
+                {
+                    m_temporary_buffer.clear();
+                    SWITCH_TO(RAWTEXTEndTagOpen);
+                }
+                ANYTHING_ELSE
+                {
+                    EMIT_CHARACTER('<');
+                    RECONSUME_IN(RAWTEXT);
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(RAWTEXTEndTagOpen)
+            {
+                ON_ASCII_ALPHA
+                {
+                    create_new_token(HTMLToken::Type::EndTag);
+                    RECONSUME_IN(RAWTEXTEndTagName);
+                }
+                ANYTHING_ELSE
+                {
+                    // FIXME: Emit a U+003C LESS-THAN SIGN character token and a U+002F SOLIDUS character token. Reconsume in the RAWTEXT state.
+                    TODO();
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(RAWTEXTEndTagName)
+            {
+                ON_WHITESPACE
+                {
+                    TODO();
+                }
+                ON('/')
+                {
+                    TODO();
+                }
+                ON('>')
+                {
+                    if (!current_end_tag_token_is_appropriate()) {
+                        // FIXME: Otherwise, treat it as per the "anything else" entry below.
+                        TODO();
+                    }
+                    SWITCH_TO_AND_EMIT_CURRENT_TOKEN(Data);
+                }
+                ON_ASCII_UPPER_ALPHA
+                {
+                    m_current_token.m_tag.tag_name.append(tolower(current_input_character.value()));
+                    m_temporary_buffer.append(current_input_character.value());
+                    continue;
+                }
+                ON_ASCII_LOWER_ALPHA
+                {
+                    m_current_token.m_tag.tag_name.append(current_input_character.value());
+                    m_temporary_buffer.append(current_input_character.value());
+                    continue;
+                }
+                ANYTHING_ELSE
+                {
+                    TODO();
+                }
+            }
+            END_STATE
+
         default:
             ASSERT_NOT_REACHED();
         }
