LibWeb: Spec-comment parse_a_stylesheet()

Also introduce a `location` parameter when parsing a CSSStyleSheet. This
is not provided by anyone yet.

Userland/Libraries/LibWeb/CSS/CSSStyleSheet.cpp

@@ -12,9 +12,11 @@
 
 namespace Web::CSS {
 
-CSSStyleSheet::CSSStyleSheet(NonnullRefPtrVector<CSSRule> rules)
+CSSStyleSheet::CSSStyleSheet(NonnullRefPtrVector<CSSRule> rules, Optional<AK::URL> location)
     : m_rules(CSSRuleList::create(move(rules)))
 {
+    if (location.has_value())
+        set_location(location->to_string());
 }
 
 // https://www.w3.org/TR/cssom/#dom-cssstylesheet-insertrule

Userland/Libraries/LibWeb/CSS/CSSStyleSheet.h

@@ -24,9 +24,9 @@ class CSSStyleSheet final
 public:
     using WrapperType = Bindings::CSSStyleSheetWrapper;
 
-    static NonnullRefPtr<CSSStyleSheet> create(NonnullRefPtrVector<CSSRule> rules)
+    static NonnullRefPtr<CSSStyleSheet> create(NonnullRefPtrVector<CSSRule> rules, Optional<AK::URL> location)
     {
-        return adopt_ref(*new CSSStyleSheet(move(rules)));
+        return adopt_ref(*new CSSStyleSheet(move(rules), move(location)));
     }
 
     virtual ~CSSStyleSheet() override = default;
@@ -53,7 +53,7 @@ public:
     void set_style_sheet_list(Badge<StyleSheetList>, StyleSheetList*);
 
 private:
-    explicit CSSStyleSheet(NonnullRefPtrVector<CSSRule>);
+    explicit CSSStyleSheet(NonnullRefPtrVector<CSSRule>, Optional<AK::URL> location);
 
     NonnullRefPtr<CSSRuleList> m_rules;
 

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

@@ -160,14 +160,26 @@ Parser::Parser(ParsingContext const& context, StringView input, String const& en
 {
 }
 
-NonnullRefPtr<CSSStyleSheet> Parser::parse_as_stylesheet()
+NonnullRefPtr<CSSStyleSheet> Parser::parse_as_stylesheet(Optional<AK::URL> location)
 {
-    return parse_a_stylesheet(m_token_stream);
+    return parse_a_stylesheet(m_token_stream, location);
 }
 
+// 5.3.3. Parse a stylesheet
+// https://www.w3.org/TR/css-syntax-3/#parse-stylesheet
 template<typename T>
-NonnullRefPtr<CSSStyleSheet> Parser::parse_a_stylesheet(TokenStream<T>& tokens)
+NonnullRefPtr<CSSStyleSheet> Parser::parse_a_stylesheet(TokenStream<T>& tokens, Optional<AK::URL> location)
 {
+    // To parse a stylesheet from an input given an optional url location:
+
+    // 1. If input is a byte stream for stylesheet, decode bytes from input, and set input to the result.
+    // 2. Normalize input, and set input to the result.
+    // NOTE: These are done automatically when creating the Parser.
+
+    // 3. Create a new stylesheet, with its location set to location (or null, if location was not passed).
+    // NOTE: We create the stylesheet at the end.
+
+    // 4. Consume a list of rules from input, with the top-level flag set, and set the stylesheet’s value to the result.
     auto parser_rules = consume_a_list_of_rules(tokens, true);
     NonnullRefPtrVector<CSSRule> rules;
 
@@ -177,7 +189,8 @@ NonnullRefPtr<CSSStyleSheet> Parser::parse_a_stylesheet(TokenStream<T>& tokens)
             rules.append(*rule);
     }
 
-    return CSSStyleSheet::create(rules);
+    // 5. Return the stylesheet.
+    return CSSStyleSheet::create(move(rules), move(location));
 }
 
 Optional<SelectorList> Parser::parse_as_selector(SelectorParsingMode parsing_mode)
@@ -5224,12 +5237,12 @@ TimePercentage Parser::Dimension::time_percentage() const
 
 namespace Web {
 
-RefPtr<CSS::CSSStyleSheet> parse_css_stylesheet(CSS::ParsingContext const& context, StringView css)
+RefPtr<CSS::CSSStyleSheet> parse_css_stylesheet(CSS::ParsingContext const& context, StringView css, Optional<AK::URL> location)
 {
     if (css.is_empty())
-        return CSS::CSSStyleSheet::create({});
+        return CSS::CSSStyleSheet::create({}, location);
     CSS::Parser parser(context, css);
-    return parser.parse_as_stylesheet();
+    return parser.parse_as_stylesheet(location);
 }
 
 RefPtr<CSS::ElementInlineCSSStyleDeclaration> parse_css_style_attribute(CSS::ParsingContext const& context, StringView css, DOM::Element& element)

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

@@ -90,7 +90,7 @@ public:
     ~Parser() = default;
 
     // The normal parser entry point, for parsing stylesheets.
-    NonnullRefPtr<CSSStyleSheet> parse_as_stylesheet();
+    NonnullRefPtr<CSSStyleSheet> parse_as_stylesheet(Optional<AK::URL> location);
     // For the content of at-rules such as @media. It differs from "Parse a stylesheet" in the handling of <CDO-token> and <CDC-token>.
     NonnullRefPtrVector<CSSRule> parse_as_list_of_rules();
     // For use by the CSSStyleSheet#insertRule method, and similar functions which might exist, which parse text into a single rule.
@@ -135,7 +135,7 @@ private:
     };
 
     template<typename T>
-    NonnullRefPtr<CSSStyleSheet> parse_a_stylesheet(TokenStream<T>&);
+    NonnullRefPtr<CSSStyleSheet> parse_a_stylesheet(TokenStream<T>&, Optional<AK::URL> location);
     template<typename T>
     NonnullRefPtrVector<CSSRule> parse_a_list_of_rules(TokenStream<T>&);
     template<typename T>
@@ -361,7 +361,7 @@ private:
 
 namespace Web {
 
-RefPtr<CSS::CSSStyleSheet> parse_css_stylesheet(CSS::ParsingContext const&, StringView);
+RefPtr<CSS::CSSStyleSheet> parse_css_stylesheet(CSS::ParsingContext const&, StringView, Optional<AK::URL> location = {});
 RefPtr<CSS::ElementInlineCSSStyleDeclaration> parse_css_style_attribute(CSS::ParsingContext const&, StringView, DOM::Element&);
 RefPtr<CSS::StyleValue> parse_css_value(CSS::ParsingContext const&, StringView, CSS::PropertyID property_id = CSS::PropertyID::Invalid);
 Optional<CSS::SelectorList> parse_selector(CSS::ParsingContext const&, StringView);