LibWeb/CSS: Make @page selector parsing accessible

Mostly minor changes - the code has moved, and has to support Token or
ComponentValue TokenStreams, but otherwise it's the same.

Libraries/LibWeb/CSS/Parser/Helpers.cpp

@@ -106,6 +106,11 @@ Optional<CSS::SelectorList> parse_selector_for_nested_style_rule(CSS::Parser::Pa
     return adapt_nested_relative_selector_list(*maybe_selectors);
 }
 
+Optional<CSS::PageSelectorList> parse_page_selector_list(CSS::Parser::ParsingParams const& params, StringView selector_text)
+{
+    return CSS::Parser::Parser::create(params, selector_text).parse_as_page_selector_list();
+}
+
 Optional<CSS::Selector::PseudoElementSelector> parse_pseudo_element_selector(CSS::Parser::ParsingParams const& context, StringView selector_text)
 {
     return CSS::Parser::Parser::create(context, selector_text).parse_as_pseudo_element_selector();

Libraries/LibWeb/CSS/Parser/Parser.h

@@ -19,6 +19,7 @@
 #include <LibWeb/CSS/Descriptor.h>
 #include <LibWeb/CSS/DescriptorID.h>
 #include <LibWeb/CSS/MediaQuery.h>
+#include <LibWeb/CSS/PageSelector.h>
 #include <LibWeb/CSS/ParsedFontFace.h>
 #include <LibWeb/CSS/Parser/ComponentValue.h>
 #include <LibWeb/CSS/Parser/Dimension.h>
@@ -117,6 +118,8 @@ public:
 
     Optional<Selector::PseudoElementSelector> parse_as_pseudo_element_selector();
 
+    Optional<PageSelectorList> parse_as_page_selector_list();
+
     Vector<NonnullRefPtr<MediaQuery>> parse_as_media_query_list();
     RefPtr<MediaQuery> parse_as_media_query();
 
@@ -188,6 +191,9 @@ private:
     template<typename T>
     ParseErrorOr<SelectorList> parse_a_selector_list(TokenStream<T>&, SelectorType, SelectorParsingMode = SelectorParsingMode::Standard);
 
+    template<typename T>
+    ParseErrorOr<PageSelectorList> parse_a_page_selector_list(TokenStream<T>&);
+
     template<typename T>
     Vector<NonnullRefPtr<MediaQuery>> parse_a_media_query_list(TokenStream<T>&);
     template<typename T>
@@ -523,6 +529,7 @@ RefPtr<CSS::CSSStyleValue const> parse_css_value(CSS::Parser::ParsingParams cons
 RefPtr<CSS::CSSStyleValue const> parse_css_descriptor(CSS::Parser::ParsingParams const&, CSS::AtRuleID, CSS::DescriptorID, StringView);
 Optional<CSS::SelectorList> parse_selector(CSS::Parser::ParsingParams const&, StringView);
 Optional<CSS::SelectorList> parse_selector_for_nested_style_rule(CSS::Parser::ParsingParams const&, StringView);
+Optional<CSS::PageSelectorList> parse_page_selector_list(CSS::Parser::ParsingParams const&, StringView);
 Optional<CSS::Selector::PseudoElementSelector> parse_pseudo_element_selector(CSS::Parser::ParsingParams const&, StringView);
 CSS::CSSRule* parse_css_rule(CSS::Parser::ParsingParams const&, StringView);
 RefPtr<CSS::MediaQuery> parse_media_query(CSS::Parser::ParsingParams const&, StringView);

Libraries/LibWeb/CSS/Parser/RuleParsing.cpp

@@ -639,74 +639,13 @@ GC::Ptr<CSSFontFaceRule> Parser::convert_to_font_face_rule(AtRule const& rule)
     return CSSFontFaceRule::create(realm(), CSSFontFaceDescriptors::create(realm(), descriptors.release_descriptors()));
 }
 
-static Optional<PageSelectorList> parse_page_selector_list(Vector<ComponentValue> const& component_values)
-{
-    // https://drafts.csswg.org/css-page-3/#syntax-page-selector
-    // <page-selector-list> = <page-selector>#
-    // <page-selector> = [ <ident-token>? <pseudo-page>* ]!
-    // <pseudo-page> = : [ left | right | first | blank ]
-
-    PageSelectorList selector_list;
-
-    TokenStream tokens { component_values };
-    tokens.discard_whitespace();
-
-    while (tokens.has_next_token()) {
-        // First optional ident
-        Optional<FlyString> maybe_ident;
-        if (tokens.next_token().is(Token::Type::Ident))
-            maybe_ident = tokens.consume_a_token().token().ident();
-
-        // Then an optional series of pseudo-classes
-        Vector<PagePseudoClass> pseudo_classes;
-        while (tokens.next_token().is(Token::Type::Colon)) {
-            tokens.discard_a_token(); // :
-            if (!tokens.next_token().is(Token::Type::Ident)) {
-                dbgln_if(CSS_PARSER_DEBUG, "Invalid @page selector: pseudo-class is not an ident: `{}`", tokens.next_token().to_debug_string());
-                return {};
-            }
-            auto pseudo_class_name = tokens.consume_a_token().token().ident();
-            if (auto pseudo_class = page_pseudo_class_from_string(pseudo_class_name); pseudo_class.has_value()) {
-                pseudo_classes.append(*pseudo_class);
-            } else {
-                dbgln_if(CSS_PARSER_DEBUG, "Invalid @page selector: unrecognized pseudo-class `:{}`", pseudo_class_name);
-                return {};
-            }
-        }
-
-        if (!maybe_ident.has_value() && pseudo_classes.is_empty()) {
-            // Nothing parsed
-            dbgln_if(CSS_PARSER_DEBUG, "Invalid @page selector: is empty");
-            return {};
-        }
-
-        selector_list.empend(move(maybe_ident), move(pseudo_classes));
-
-        tokens.discard_whitespace();
-
-        if (tokens.next_token().is(Token::Type::Comma)) {
-            tokens.discard_a_token(); // ,
-            tokens.discard_whitespace();
-            if (!tokens.has_next_token()) {
-                dbgln_if(CSS_PARSER_DEBUG, "Invalid @page selector: trailing comma");
-                return {};
-            }
-
-        } else if (tokens.has_next_token()) {
-            dbgln_if(CSS_PARSER_DEBUG, "Invalid @page selector: trailing token `{}`", tokens.next_token().to_debug_string());
-            return {};
-        }
-    }
-
-    return selector_list;
-}
-
 GC::Ptr<CSSPageRule> Parser::convert_to_page_rule(AtRule const& page_rule)
 {
     // https://drafts.csswg.org/css-page-3/#syntax-page-selector
     // @page = @page <page-selector-list>? { <declaration-rule-list> }
-    auto page_selectors = parse_page_selector_list(page_rule.prelude);
+    TokenStream tokens { page_rule.prelude };
-    if (!page_selectors.has_value())
+    auto page_selectors = parse_a_page_selector_list(tokens);
+    if (page_selectors.is_error())
         return nullptr;
 
     GC::RootVector<GC::Ref<CSSRule>> child_rules { realm().heap() };

Libraries/LibWeb/CSS/Parser/SelectorParsing.cpp

@@ -1147,4 +1147,76 @@ Optional<Selector::SimpleSelector::ANPlusBPattern> Parser::parse_a_n_plus_b_patt
     return syntax_error();
 }
 
+Optional<PageSelectorList> Parser::parse_as_page_selector_list()
+{
+    auto selector_list = parse_a_page_selector_list(m_token_stream);
+    if (!selector_list.is_error())
+        return selector_list.release_value();
+    return {};
+}
+
+template<typename T>
+Parser::ParseErrorOr<PageSelectorList> Parser::parse_a_page_selector_list(TokenStream<T>& tokens)
+{
+    // https://drafts.csswg.org/css-page-3/#syntax-page-selector
+    // <page-selector-list> = <page-selector>#
+    // <page-selector> = [ <ident-token>? <pseudo-page>* ]!
+    // <pseudo-page> = : [ left | right | first | blank ]
+
+    PageSelectorList selector_list;
+
+    tokens.discard_whitespace();
+
+    while (tokens.has_next_token()) {
+        // First optional ident
+        Optional<FlyString> maybe_ident;
+        if (tokens.next_token().is(Token::Type::Ident))
+            maybe_ident = static_cast<Token>(tokens.consume_a_token()).ident();
+
+        // Then an optional series of pseudo-classes
+        Vector<PagePseudoClass> pseudo_classes;
+        while (tokens.next_token().is(Token::Type::Colon)) {
+            tokens.discard_a_token(); // :
+            if (!tokens.next_token().is(Token::Type::Ident)) {
+                dbgln_if(CSS_PARSER_DEBUG, "Invalid @page selector: pseudo-class is not an ident: `{}`", tokens.next_token().to_debug_string());
+                return ParseError::SyntaxError;
+            }
+            auto pseudo_class_name = static_cast<Token>(tokens.consume_a_token()).ident();
+            if (auto pseudo_class = page_pseudo_class_from_string(pseudo_class_name); pseudo_class.has_value()) {
+                pseudo_classes.append(*pseudo_class);
+            } else {
+                dbgln_if(CSS_PARSER_DEBUG, "Invalid @page selector: unrecognized pseudo-class `:{}`", pseudo_class_name);
+                return ParseError::SyntaxError;
+            }
+        }
+
+        if (!maybe_ident.has_value() && pseudo_classes.is_empty()) {
+            // Nothing parsed
+            dbgln_if(CSS_PARSER_DEBUG, "Invalid @page selector: is empty");
+            return ParseError::SyntaxError;
+        }
+
+        selector_list.empend(move(maybe_ident), move(pseudo_classes));
+
+        tokens.discard_whitespace();
+
+        if (tokens.next_token().is(Token::Type::Comma)) {
+            tokens.discard_a_token(); // ,
+            tokens.discard_whitespace();
+            if (!tokens.has_next_token()) {
+                dbgln_if(CSS_PARSER_DEBUG, "Invalid @page selector: trailing comma");
+                return ParseError::SyntaxError;
+            }
+
+        } else if (tokens.has_next_token()) {
+            dbgln_if(CSS_PARSER_DEBUG, "Invalid @page selector: trailing token `{}`", tokens.next_token().to_debug_string());
+            return ParseError::SyntaxError;
+        }
+    }
+
+    return selector_list;
+}
+template Parser::ParseErrorOr<PageSelectorList> Parser::parse_a_page_selector_list(TokenStream<ComponentValue>&);
+template Parser::ParseErrorOr<PageSelectorList> Parser::parse_a_page_selector_list(TokenStream<Token>&);
+
 }