LibWeb: Propagate errors when parsing StyleValues

This necessitated returning `nullptr` instead of just `{}` in a lot of
places. Also, some temporary hackiness in `parse_css_value()`: That
returns a special `ParseError` type already, so we now have a
`FIXME_TRY()` macro which logs the error and then returns a generic
`ParseError::InternalError` value. Eventually this macro will go away,
once I figure out how to deal with this more nicely.

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

@@ -85,16 +85,17 @@ public:
 
     RefPtr<Supports> parse_as_supports();
 
-    RefPtr<StyleValue> parse_as_css_value(PropertyID);
+    ErrorOr<RefPtr<StyleValue>> parse_as_css_value(PropertyID);
 
-    static RefPtr<StyleValue> parse_css_value(Badge<StyleComputer>, ParsingContext const&, PropertyID, Vector<ComponentValue> const&);
-    static RefPtr<CalculatedStyleValue> parse_calculated_value(Badge<StyleComputer>, ParsingContext const&, Vector<ComponentValue> const&);
+    static ErrorOr<RefPtr<StyleValue>> parse_css_value(Badge<StyleComputer>, ParsingContext const&, PropertyID, Vector<ComponentValue> const&);
+    static ErrorOr<RefPtr<CalculatedStyleValue>> parse_calculated_value(Badge<StyleComputer>, ParsingContext const&, Vector<ComponentValue> const&);
 
 private:
     Parser(ParsingContext const&, Vector<Token>);
 
     enum class ParseError {
         IncludesIgnoredVendorPrefix,
+        InternalError,
         SyntaxError,
     };
     template<typename T>
@@ -267,64 +268,64 @@ private:
         Font,
     };
     Optional<AK::URL> parse_url_function(ComponentValue const&, AllowedDataUrlType = AllowedDataUrlType::None);
-    RefPtr<StyleValue> parse_url_value(ComponentValue const&, AllowedDataUrlType = AllowedDataUrlType::None);
+    ErrorOr<RefPtr<StyleValue>> parse_url_value(ComponentValue const&, AllowedDataUrlType = AllowedDataUrlType::None);
 
     Optional<Vector<LinearColorStopListElement>> parse_linear_color_stop_list(TokenStream<ComponentValue>&);
     Optional<Vector<AngularColorStopListElement>> parse_angular_color_stop_list(TokenStream<ComponentValue>&);
 
-    RefPtr<StyleValue> parse_linear_gradient_function(ComponentValue const&);
-    RefPtr<StyleValue> parse_conic_gradient_function(ComponentValue const&);
-    RefPtr<StyleValue> parse_radial_gradient_function(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_linear_gradient_function(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_conic_gradient_function(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_radial_gradient_function(ComponentValue const&);
 
     ParseErrorOr<NonnullRefPtr<StyleValue>> parse_css_value(PropertyID, TokenStream<ComponentValue>&);
-    RefPtr<StyleValue> parse_css_value(ComponentValue const&);
-    RefPtr<StyleValue> parse_builtin_value(ComponentValue const&);
-    RefPtr<StyleValue> parse_dynamic_value(ComponentValue const&);
-    RefPtr<CalculatedStyleValue> parse_calculated_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_dimension_value(ComponentValue const&);
-    RefPtr<StyleValue> parse_numeric_value(ComponentValue const&);
-    RefPtr<StyleValue> parse_identifier_value(ComponentValue const&);
-    RefPtr<StyleValue> parse_color_value(ComponentValue const&);
-    RefPtr<StyleValue> parse_rect_value(ComponentValue const&);
-    RefPtr<StyleValue> parse_string_value(ComponentValue const&);
-    RefPtr<StyleValue> parse_image_value(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_css_value(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_builtin_value(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_dynamic_value(ComponentValue const&);
+    ErrorOr<RefPtr<CalculatedStyleValue>> parse_calculated_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_dimension_value(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_numeric_value(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_identifier_value(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_color_value(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_rect_value(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_string_value(ComponentValue const&);
+    ErrorOr<RefPtr<StyleValue>> parse_image_value(ComponentValue const&);
     template<typename ParseFunction>
-    RefPtr<StyleValue> parse_comma_separated_value_list(Vector<ComponentValue> const&, ParseFunction);
-    RefPtr<StyleValue> parse_simple_comma_separated_value_list(Vector<ComponentValue> const&);
-
-    RefPtr<StyleValue> parse_filter_value_list_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_background_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_single_background_position_value(TokenStream<ComponentValue>&);
-    RefPtr<StyleValue> parse_single_background_position_x_or_y_value(TokenStream<ComponentValue>&, PropertyID);
-    RefPtr<StyleValue> parse_single_background_repeat_value(TokenStream<ComponentValue>&);
-    RefPtr<StyleValue> parse_single_background_size_value(TokenStream<ComponentValue>&);
-    RefPtr<StyleValue> parse_border_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_border_radius_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_border_radius_shorthand_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_content_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_display_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_flex_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_flex_flow_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_font_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_font_family_value(Vector<ComponentValue> const&, size_t start_index = 0);
-    RefPtr<StyleValue> parse_list_style_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_overflow_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_comma_separated_value_list(Vector<ComponentValue> const&, ParseFunction);
+    ErrorOr<RefPtr<StyleValue>> parse_simple_comma_separated_value_list(Vector<ComponentValue> const&);
+
+    ErrorOr<RefPtr<StyleValue>> parse_filter_value_list_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_background_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_single_background_position_value(TokenStream<ComponentValue>&);
+    ErrorOr<RefPtr<StyleValue>> parse_single_background_position_x_or_y_value(TokenStream<ComponentValue>&, PropertyID);
+    ErrorOr<RefPtr<StyleValue>> parse_single_background_repeat_value(TokenStream<ComponentValue>&);
+    ErrorOr<RefPtr<StyleValue>> parse_single_background_size_value(TokenStream<ComponentValue>&);
+    ErrorOr<RefPtr<StyleValue>> parse_border_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_border_radius_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_border_radius_shorthand_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_content_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_display_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_flex_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_flex_flow_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_font_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_font_family_value(Vector<ComponentValue> const&, size_t start_index = 0);
+    ErrorOr<RefPtr<StyleValue>> parse_list_style_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_overflow_value(Vector<ComponentValue> const&);
     enum class AllowInsetKeyword {
         No,
         Yes,
     };
-    RefPtr<StyleValue> parse_shadow_value(Vector<ComponentValue> const&, AllowInsetKeyword);
-    RefPtr<StyleValue> parse_single_shadow_value(TokenStream<ComponentValue>&, AllowInsetKeyword);
-    RefPtr<StyleValue> parse_text_decoration_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_text_decoration_line_value(TokenStream<ComponentValue>&);
-    RefPtr<StyleValue> parse_transform_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_transform_origin_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_grid_track_size_list(Vector<ComponentValue> const&, bool allow_separate_line_name_blocks = false);
-    RefPtr<StyleValue> parse_grid_track_size_list_shorthand_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_grid_track_placement(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_grid_track_placement_shorthand_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_grid_template_areas_value(Vector<ComponentValue> const&);
-    RefPtr<StyleValue> parse_grid_area_shorthand_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_shadow_value(Vector<ComponentValue> const&, AllowInsetKeyword);
+    ErrorOr<RefPtr<StyleValue>> parse_single_shadow_value(TokenStream<ComponentValue>&, AllowInsetKeyword);
+    ErrorOr<RefPtr<StyleValue>> parse_text_decoration_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_text_decoration_line_value(TokenStream<ComponentValue>&);
+    ErrorOr<RefPtr<StyleValue>> parse_transform_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_transform_origin_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_grid_track_size_list(Vector<ComponentValue> const&, bool allow_separate_line_name_blocks = false);
+    ErrorOr<RefPtr<StyleValue>> parse_grid_track_size_list_shorthand_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_grid_track_placement(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_grid_track_placement_shorthand_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_grid_template_areas_value(Vector<ComponentValue> const&);
+    ErrorOr<RefPtr<StyleValue>> parse_grid_area_shorthand_value(Vector<ComponentValue> const&);
 
     ErrorOr<OwnPtr<CalculationNode>> parse_a_calculation(Vector<ComponentValue> const&);
 

Userland/Libraries/LibWeb/CSS/StyleComputer.cpp

@@ -802,7 +802,7 @@ bool StyleComputer::expand_unresolved_values(DOM::Element& element, StringView p
 
             if (value.function().name().equals_ignoring_ascii_case("calc"sv)) {
                 auto const& calc_function = value.function();
-                if (auto calc_value = CSS::Parser::Parser::parse_calculated_value({}, Parser::ParsingContext { document() }, calc_function.values())) {
+                if (auto calc_value = Parser::Parser::parse_calculated_value({}, Parser::ParsingContext { document() }, calc_function.values()).release_value_but_fixme_should_propagate_errors()) {
                     switch (calc_value->resolved_type()) {
                     case CalculatedStyleValue::ResolvedType::Integer: {
                         auto resolved_value = calc_value->resolve_integer();
@@ -865,7 +865,7 @@ RefPtr<StyleValue> StyleComputer::resolve_unresolved_style_value(DOM::Element& e
     if (!expand_unresolved_values(element, string_from_property_id(property_id), unresolved_values_with_variables_expanded, expanded_values))
         return {};
 
-    if (auto parsed_value = Parser::Parser::parse_css_value({}, Parser::ParsingContext { document() }, property_id, expanded_values))
+    if (auto parsed_value = Parser::Parser::parse_css_value({}, Parser::ParsingContext { document() }, property_id, expanded_values).release_value_but_fixme_should_propagate_errors())
         return parsed_value.release_nonnull();
 
     return {};