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	 0795b9f7bb
			
		
	
	
		0795b9f7bb
		
	
	
	
	
		
			
			Using doubles isn't necessary, and they make things slightly bigger and slower, so let's use floats instead.
		
			
				
	
	
		
			481 lines
		
	
	
	
		
			16 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			481 lines
		
	
	
	
		
			16 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #include <LibWeb/CSS/MediaQuery.h>
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| #include <LibWeb/CSS/Serialize.h>
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| #include <LibWeb/DOM/Document.h>
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| #include <LibWeb/HTML/Window.h>
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| 
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| namespace Web::CSS {
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| 
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| NonnullRefPtr<MediaQuery> MediaQuery::create_not_all()
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| {
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|     auto media_query = new MediaQuery;
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|     media_query->m_negated = true;
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|     media_query->m_media_type = MediaType::All;
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| 
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|     return adopt_ref(*media_query);
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| }
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| 
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| String MediaFeatureValue::to_string() const
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| {
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|     return m_value.visit(
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|         [](ValueID const& ident) { return String { string_from_value_id(ident) }; },
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|         [](Length const& length) { return length.to_string(); },
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|         [](Ratio const& ratio) { return ratio.to_string(); },
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|         [](Resolution const& resolution) { return resolution.to_string(); },
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|         [](float number) { return String::number(number); });
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| }
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| 
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| bool MediaFeatureValue::is_same_type(MediaFeatureValue const& other) const
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| {
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|     return m_value.visit(
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|         [&](ValueID const&) { return other.is_ident(); },
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|         [&](Length const&) { return other.is_length(); },
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|         [&](Ratio const&) { return other.is_ratio(); },
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|         [&](Resolution const&) { return other.is_resolution(); },
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|         [&](float) { return other.is_number(); });
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| }
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| 
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| String MediaFeature::to_string() const
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| {
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|     auto comparison_string = [](Comparison comparison) -> StringView {
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|         switch (comparison) {
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|         case Comparison::Equal:
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|             return "="sv;
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|         case Comparison::LessThan:
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|             return "<"sv;
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|         case Comparison::LessThanOrEqual:
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|             return "<="sv;
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|         case Comparison::GreaterThan:
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|             return ">"sv;
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|         case Comparison::GreaterThanOrEqual:
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|             return ">="sv;
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|         }
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|         VERIFY_NOT_REACHED();
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|     };
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| 
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|     switch (m_type) {
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|     case Type::IsTrue:
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|         return string_from_media_feature_id(m_id);
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|     case Type::ExactValue:
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|         return String::formatted("{}:{}", string_from_media_feature_id(m_id), m_value->to_string());
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|     case Type::MinValue:
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|         return String::formatted("min-{}:{}", string_from_media_feature_id(m_id), m_value->to_string());
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|     case Type::MaxValue:
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|         return String::formatted("max-{}:{}", string_from_media_feature_id(m_id), m_value->to_string());
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|     case Type::Range:
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|         if (!m_range->right_comparison.has_value())
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|             return String::formatted("{} {} {}", m_range->left_value.to_string(), comparison_string(m_range->left_comparison), string_from_media_feature_id(m_id));
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| 
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|         return String::formatted("{} {} {} {} {}", m_range->left_value.to_string(), comparison_string(m_range->left_comparison), string_from_media_feature_id(m_id), comparison_string(*m_range->right_comparison), m_range->right_value->to_string());
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|     }
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| 
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|     VERIFY_NOT_REACHED();
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| }
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| 
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| bool MediaFeature::evaluate(HTML::Window const& window) const
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| {
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|     auto maybe_queried_value = window.query_media_feature(m_id);
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|     if (!maybe_queried_value.has_value())
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|         return false;
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|     auto queried_value = maybe_queried_value.release_value();
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| 
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|     switch (m_type) {
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|     case Type::IsTrue:
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|         if (queried_value.is_number())
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|             return queried_value.number() != 0;
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|         if (queried_value.is_length())
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|             return queried_value.length().raw_value() != 0;
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|         // FIXME: I couldn't figure out from the spec how ratios should be evaluated in a boolean context.
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|         if (queried_value.is_ratio())
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|             return !queried_value.ratio().is_degenerate();
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|         if (queried_value.is_resolution())
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|             return queried_value.resolution().to_dots_per_pixel() != 0;
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|         if (queried_value.is_ident()) {
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|             // NOTE: It is not technically correct to always treat `no-preference` as false, but every
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|             //       media-feature that accepts it as a value treats it as false, so good enough. :^)
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|             //       If other features gain this property for other identifiers in the future, we can
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|             //       add more robust handling for them then.
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|             return queried_value.ident() != ValueID::None
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|                 && queried_value.ident() != ValueID::NoPreference;
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|         }
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|         return false;
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| 
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|     case Type::ExactValue:
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|         return compare(window, *m_value, Comparison::Equal, queried_value);
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| 
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|     case Type::MinValue:
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|         return compare(window, queried_value, Comparison::GreaterThanOrEqual, *m_value);
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| 
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|     case Type::MaxValue:
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|         return compare(window, queried_value, Comparison::LessThanOrEqual, *m_value);
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| 
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|     case Type::Range:
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|         if (!compare(window, m_range->left_value, m_range->left_comparison, queried_value))
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|             return false;
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| 
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|         if (m_range->right_comparison.has_value())
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|             if (!compare(window, queried_value, *m_range->right_comparison, *m_range->right_value))
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|                 return false;
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| 
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|         return true;
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|     }
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| 
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|     VERIFY_NOT_REACHED();
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| }
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| 
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| bool MediaFeature::compare(HTML::Window const& window, MediaFeatureValue left, Comparison comparison, MediaFeatureValue right)
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| {
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|     if (!left.is_same_type(right))
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|         return false;
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| 
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|     if (left.is_ident()) {
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|         if (comparison == Comparison::Equal)
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|             return left.ident() == right.ident();
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|         return false;
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|     }
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| 
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|     if (left.is_number()) {
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|         switch (comparison) {
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|         case Comparison::Equal:
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|             return left.number() == right.number();
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|         case Comparison::LessThan:
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|             return left.number() < right.number();
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|         case Comparison::LessThanOrEqual:
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|             return left.number() <= right.number();
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|         case Comparison::GreaterThan:
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|             return left.number() > right.number();
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|         case Comparison::GreaterThanOrEqual:
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|             return left.number() >= right.number();
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|         }
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|         VERIFY_NOT_REACHED();
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|     }
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| 
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|     if (left.is_length()) {
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|         float left_px;
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|         float right_px;
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|         // Save ourselves some work if neither side is a relative length.
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|         if (left.length().is_absolute() && right.length().is_absolute()) {
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|             left_px = left.length().absolute_length_to_px();
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|             right_px = right.length().absolute_length_to_px();
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|         } else {
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|             Gfx::IntRect viewport_rect { 0, 0, window.inner_width(), window.inner_height() };
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| 
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|             auto const& initial_font = window.associated_document().style_computer().initial_font();
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|             Gfx::FontMetrics const& initial_font_metrics = initial_font.metrics('M');
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|             float initial_font_size = initial_font.presentation_size();
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| 
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|             left_px = left.length().to_px(viewport_rect, initial_font_metrics, initial_font_size, initial_font_size);
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|             right_px = right.length().to_px(viewport_rect, initial_font_metrics, initial_font_size, initial_font_size);
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|         }
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| 
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|         switch (comparison) {
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|         case Comparison::Equal:
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|             return left_px == right_px;
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|         case Comparison::LessThan:
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|             return left_px < right_px;
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|         case Comparison::LessThanOrEqual:
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|             return left_px <= right_px;
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|         case Comparison::GreaterThan:
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|             return left_px > right_px;
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|         case Comparison::GreaterThanOrEqual:
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|             return left_px >= right_px;
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|         }
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| 
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|         VERIFY_NOT_REACHED();
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|     }
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| 
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|     if (left.is_ratio()) {
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|         auto left_decimal = left.ratio().value();
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|         auto right_decimal = right.ratio().value();
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| 
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|         switch (comparison) {
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|         case Comparison::Equal:
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|             return left_decimal == right_decimal;
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|         case Comparison::LessThan:
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|             return left_decimal < right_decimal;
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|         case Comparison::LessThanOrEqual:
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|             return left_decimal <= right_decimal;
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|         case Comparison::GreaterThan:
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|             return left_decimal > right_decimal;
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|         case Comparison::GreaterThanOrEqual:
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|             return left_decimal >= right_decimal;
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|         }
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|         VERIFY_NOT_REACHED();
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|     }
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| 
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|     if (left.is_resolution()) {
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|         auto left_dppx = left.resolution().to_dots_per_pixel();
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|         auto right_dppx = right.resolution().to_dots_per_pixel();
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| 
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|         switch (comparison) {
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|         case Comparison::Equal:
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|             return left_dppx == right_dppx;
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|         case Comparison::LessThan:
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|             return left_dppx < right_dppx;
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|         case Comparison::LessThanOrEqual:
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|             return left_dppx <= right_dppx;
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|         case Comparison::GreaterThan:
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|             return left_dppx > right_dppx;
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|         case Comparison::GreaterThanOrEqual:
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|             return left_dppx >= right_dppx;
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|         }
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|         VERIFY_NOT_REACHED();
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|     }
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| 
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|     VERIFY_NOT_REACHED();
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| }
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| 
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| NonnullOwnPtr<MediaCondition> MediaCondition::from_general_enclosed(GeneralEnclosed&& general_enclosed)
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| {
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|     auto result = new MediaCondition;
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|     result->type = Type::GeneralEnclosed;
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|     result->general_enclosed = move(general_enclosed);
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| 
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|     return adopt_own(*result);
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| }
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| 
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| NonnullOwnPtr<MediaCondition> MediaCondition::from_feature(MediaFeature&& feature)
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| {
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|     auto result = new MediaCondition;
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|     result->type = Type::Single;
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|     result->feature = move(feature);
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| 
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|     return adopt_own(*result);
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| }
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| 
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| NonnullOwnPtr<MediaCondition> MediaCondition::from_not(NonnullOwnPtr<MediaCondition>&& condition)
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| {
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|     auto result = new MediaCondition;
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|     result->type = Type::Not;
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|     result->conditions.append(move(condition));
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| 
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|     return adopt_own(*result);
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| }
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| 
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| NonnullOwnPtr<MediaCondition> MediaCondition::from_and_list(NonnullOwnPtrVector<MediaCondition>&& conditions)
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| {
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|     auto result = new MediaCondition;
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|     result->type = Type::And;
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|     result->conditions = move(conditions);
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| 
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|     return adopt_own(*result);
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| }
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| 
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| NonnullOwnPtr<MediaCondition> MediaCondition::from_or_list(NonnullOwnPtrVector<MediaCondition>&& conditions)
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| {
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|     auto result = new MediaCondition;
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|     result->type = Type::Or;
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|     result->conditions = move(conditions);
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| 
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|     return adopt_own(*result);
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| }
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| 
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| String MediaCondition::to_string() const
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| {
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|     StringBuilder builder;
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|     builder.append('(');
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|     switch (type) {
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|     case Type::Single:
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|         builder.append(feature->to_string());
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|         break;
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|     case Type::Not:
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|         builder.append("not ");
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|         builder.append(conditions.first().to_string());
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|         break;
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|     case Type::And:
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|         builder.join(" and ", conditions);
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|         break;
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|     case Type::Or:
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|         builder.join(" or ", conditions);
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|         break;
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|     case Type::GeneralEnclosed:
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|         builder.append(general_enclosed->to_string());
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|         break;
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|     }
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|     builder.append(')');
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|     return builder.to_string();
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| }
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| 
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| MatchResult MediaCondition::evaluate(HTML::Window const& window) const
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| {
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|     switch (type) {
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|     case Type::Single:
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|         return as_match_result(feature->evaluate(window));
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|     case Type::Not:
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|         return negate(conditions.first().evaluate(window));
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|     case Type::And:
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|         return evaluate_and(conditions, [&](auto& child) { return child.evaluate(window); });
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|     case Type::Or:
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|         return evaluate_or(conditions, [&](auto& child) { return child.evaluate(window); });
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|     case Type::GeneralEnclosed:
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|         return general_enclosed->evaluate();
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|     }
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|     VERIFY_NOT_REACHED();
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| }
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| 
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| String MediaQuery::to_string() const
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| {
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|     StringBuilder builder;
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| 
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|     if (m_negated)
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|         builder.append("not ");
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| 
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|     if (m_negated || m_media_type != MediaType::All || !m_media_condition) {
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|         switch (m_media_type) {
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|         case MediaType::All:
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|             builder.append("all");
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|             break;
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|         case MediaType::Aural:
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|             builder.append("aural");
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|             break;
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|         case MediaType::Braille:
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|             builder.append("braille");
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|             break;
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|         case MediaType::Embossed:
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|             builder.append("embossed");
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|             break;
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|         case MediaType::Handheld:
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|             builder.append("handheld");
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|             break;
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|         case MediaType::Print:
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|             builder.append("print");
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|             break;
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|         case MediaType::Projection:
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|             builder.append("projection");
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|             break;
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|         case MediaType::Screen:
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|             builder.append("screen");
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|             break;
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|         case MediaType::Speech:
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|             builder.append("speech");
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|             break;
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|         case MediaType::TTY:
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|             builder.append("tty");
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|             break;
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|         case MediaType::TV:
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|             builder.append("tv");
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|             break;
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|         }
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|         if (m_media_condition)
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|             builder.append(" and ");
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|     }
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| 
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|     if (m_media_condition) {
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|         builder.append(m_media_condition->to_string());
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|     }
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| 
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|     return builder.to_string();
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| }
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| 
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| bool MediaQuery::evaluate(HTML::Window const& window)
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| {
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|     auto matches_media = [](MediaType media) -> MatchResult {
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|         switch (media) {
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|         case MediaType::All:
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|             return MatchResult::True;
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|         case MediaType::Print:
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|             // FIXME: Enable for printing, when we have printing!
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|             return MatchResult::False;
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|         case MediaType::Screen:
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|             // FIXME: Disable for printing, when we have printing!
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|             return MatchResult::True;
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|         // Deprecated, must never match:
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|         case MediaType::TTY:
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|         case MediaType::TV:
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|         case MediaType::Projection:
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|         case MediaType::Handheld:
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|         case MediaType::Braille:
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|         case MediaType::Embossed:
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|         case MediaType::Aural:
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|         case MediaType::Speech:
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|             return MatchResult::False;
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|         }
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|         VERIFY_NOT_REACHED();
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|     };
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| 
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|     MatchResult result = matches_media(m_media_type);
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| 
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|     if ((result == MatchResult::True) && m_media_condition)
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|         result = m_media_condition->evaluate(window);
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| 
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|     if (m_negated)
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|         result = negate(result);
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| 
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|     m_matches = result == MatchResult::True;
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|     return m_matches;
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| }
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| 
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| // https://www.w3.org/TR/cssom-1/#serialize-a-media-query-list
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| String serialize_a_media_query_list(NonnullRefPtrVector<MediaQuery> const& media_queries)
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| {
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|     // 1. If the media query list is empty, then return the empty string.
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|     if (media_queries.is_empty())
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|         return "";
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| 
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|     // 2. Serialize each media query in the list of media queries, in the same order as they
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|     // appear in the media query list, and then serialize the list.
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|     StringBuilder builder;
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|     builder.join(", ", media_queries);
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|     return builder.to_string();
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| }
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| 
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| bool is_media_feature_name(StringView name)
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| {
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|     // MEDIAQUERIES-4 - https://www.w3.org/TR/mediaqueries-4/#media-descriptor-table
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|     if (name.equals_ignoring_case("any-hover"sv))
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|         return true;
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|     if (name.equals_ignoring_case("any-pointer"sv))
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|         return true;
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|     if (name.equals_ignoring_case("aspect-ratio"sv))
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|         return true;
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|     if (name.equals_ignoring_case("color"sv))
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|         return true;
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|     if (name.equals_ignoring_case("color-gamut"sv))
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|         return true;
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|     if (name.equals_ignoring_case("color-index"sv))
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|         return true;
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|     if (name.equals_ignoring_case("device-aspect-ratio"sv))
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|         return true;
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|     if (name.equals_ignoring_case("device-height"sv))
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|         return true;
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|     if (name.equals_ignoring_case("device-width"sv))
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|         return true;
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|     if (name.equals_ignoring_case("grid"sv))
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|         return true;
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|     if (name.equals_ignoring_case("height"sv))
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|         return true;
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|     if (name.equals_ignoring_case("hover"sv))
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|         return true;
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|     if (name.equals_ignoring_case("monochrome"sv))
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|         return true;
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|     if (name.equals_ignoring_case("orientation"sv))
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|         return true;
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|     if (name.equals_ignoring_case("overflow-block"sv))
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|         return true;
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|     if (name.equals_ignoring_case("overflow-inline"sv))
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|         return true;
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|     if (name.equals_ignoring_case("pointer"sv))
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|         return true;
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|     if (name.equals_ignoring_case("resolution"sv))
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|         return true;
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|     if (name.equals_ignoring_case("scan"sv))
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|         return true;
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|     if (name.equals_ignoring_case("update"sv))
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|         return true;
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|     if (name.equals_ignoring_case("width"sv))
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|         return true;
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| 
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|     // MEDIAQUERIES-5 - https://www.w3.org/TR/mediaqueries-5/#media-descriptor-table
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|     if (name.equals_ignoring_case("prefers-color-scheme"sv))
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|         return true;
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|     // FIXME: Add other level 5 feature names
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| 
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|     return false;
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| }
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| 
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| }
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