LibWeb/CSS: Preserve original source text for ComponentValues

This requires a little bit of ad-hoc tracking of start/end Tokens for
Function and SimpleBlock.

Userland/Libraries/LibWeb/CSS/Parser/ComponentValue.cpp

@@ -36,10 +36,7 @@ bool ComponentValue::is_ident(StringView ident) const
 
 String ComponentValue::to_string() const
 {
-    return m_value.visit(
-        [](Token const& token) { return token.to_string(); },
-        [](SimpleBlock const& block) { return block.to_string(); },
-        [](Function const& function) { return function.to_string(); });
+    return m_value.visit([](auto const& it) { return it.to_string(); });
 }
 
 String ComponentValue::to_debug_string() const
@@ -56,4 +53,9 @@ String ComponentValue::to_debug_string() const
         });
 }
 
+String ComponentValue::original_source_text() const
+{
+    return m_value.visit([](auto const& it) { return it.original_source_text(); });
+}
+
 }

Userland/Libraries/LibWeb/CSS/Parser/ComponentValue.h

@@ -41,6 +41,7 @@ public:
 
     String to_string() const;
     String to_debug_string() const;
+    String original_source_text() const;
 
 private:
     Variant<Token, Function, SimpleBlock> m_value;

Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp

@@ -788,7 +788,8 @@ SimpleBlock Parser::consume_a_simple_block(TokenStream<T>& input)
         // ending token
         if (token.is(Token::Type::EndOfFile) || token.is(ending_token)) {
             // Discard a token from input. Return block.
-            input.discard_a_token();
+            // AD-HOC: Store the token instead as the "end token"
+            block.end_token = input.consume_a_token();
             return block;
         }
 
@@ -811,9 +812,11 @@ Function Parser::consume_a_function(TokenStream<T>& input)
 
     // Consume a token from input, and let function be a new function with its name equal the returned token’s value,
     // and a value set to an empty list.
+    auto name_token = ((Token)input.consume_a_token());
     Function function {
-        .name = ((Token)input.consume_a_token()).function(),
+        .name = name_token.function(),
         .value = {},
+        .name_token = name_token,
     };
 
     // Process input:
@@ -824,7 +827,8 @@ Function Parser::consume_a_function(TokenStream<T>& input)
         // <)-token>
         if (token.is(Token::Type::EndOfFile) || token.is(Token::Type::CloseParen)) {
             // Discard a token from input. Return function.
-            input.discard_a_token();
+            // AD-HOC: Store the token instead as the "end token"
+            function.end_token = input.consume_a_token();
             return function;
         }
 

Userland/Libraries/LibWeb/CSS/Parser/Types.cpp

@@ -40,6 +40,17 @@ String SimpleBlock::to_string() const
     return builder.to_string_without_validation();
 }
 
+String SimpleBlock::original_source_text() const
+{
+    StringBuilder builder;
+    builder.append(token.original_source_text());
+    for (auto const& component_value : value) {
+        builder.append(component_value.original_source_text());
+    }
+    builder.append(end_token.original_source_text());
+    return builder.to_string_without_validation();
+}
+
 String Function::to_string() const
 {
     StringBuilder builder;
@@ -53,6 +64,17 @@ String Function::to_string() const
     return builder.to_string_without_validation();
 }
 
+String Function::original_source_text() const
+{
+    StringBuilder builder;
+    builder.append(name_token.original_source_text());
+    for (auto const& component_value : value) {
+        builder.append(component_value.original_source_text());
+    }
+    builder.append(end_token.original_source_text());
+    return builder.to_string_without_validation();
+}
+
 void AtRule::for_each(AtRuleVisitor&& visit_at_rule, QualifiedRuleVisitor&& visit_qualified_rule, DeclarationVisitor&& visit_declaration) const
 {
     for (auto const& child : child_rules_and_lists_of_declarations) {

Userland/Libraries/LibWeb/CSS/Parser/Types.h

@@ -63,20 +63,25 @@ struct Declaration {
 struct SimpleBlock {
     Token token;
     Vector<ComponentValue> value;
+    Token end_token = {};
 
     bool is_curly() const { return token.is(Token::Type::OpenCurly); }
     bool is_paren() const { return token.is(Token::Type::OpenParen); }
     bool is_square() const { return token.is(Token::Type::OpenSquare); }
 
     String to_string() const;
+    String original_source_text() const;
 };
 
 // https://drafts.csswg.org/css-syntax/#function
 struct Function {
     FlyString name;
     Vector<ComponentValue> value;
+    Token name_token = {};
+    Token end_token = {};
 
     String to_string() const;
+    String original_source_text() const;
 };
 
 }