From 5d57723ebf85c58e38166859c70d09dfc96110c9 Mon Sep 17 00:00:00 2001
From: Tim Ledbetter <tim.ledbetter@ladybird.org>
Date: Wed, 19 Mar 2025 11:32:34 +0000
Subject: [PATCH] LibWeb: Implement `CSSImportRule.supportsText`

Returns the supports condition specified by the given import at-rule.
---
 Libraries/LibWeb/CSS/CSSImportRule.cpp          |  7 +++++++
 Libraries/LibWeb/CSS/CSSImportRule.h            |  2 ++
 Libraries/LibWeb/CSS/CSSImportRule.idl          |  2 +-
 Libraries/LibWeb/CSS/Parser/Parser.cpp          |  4 +++-
 Libraries/LibWeb/CSS/Supports.cpp               |  2 +-
 .../expected/css/CSSImportRule-supportsText.txt |  4 ++++
 .../input/css/CSSImportRule-supportsText.html   | 17 +++++++++++++++++
 7 files changed, 35 insertions(+), 3 deletions(-)
 create mode 100644 Tests/LibWeb/Text/expected/css/CSSImportRule-supportsText.txt
 create mode 100644 Tests/LibWeb/Text/input/css/CSSImportRule-supportsText.html

diff --git a/Libraries/LibWeb/CSS/CSSImportRule.cpp b/Libraries/LibWeb/CSS/CSSImportRule.cpp
index 9c9d77088e3..f0cc8d7fa8d 100644
--- a/Libraries/LibWeb/CSS/CSSImportRule.cpp
+++ b/Libraries/LibWeb/CSS/CSSImportRule.cpp
@@ -171,4 +171,11 @@ void CSSImportRule::set_style_sheet(GC::Ref<CSSStyleSheet> style_sheet)
     m_document->invalidate_style(DOM::StyleInvalidationReason::CSSImportRule);
 }
 
+Optional<String> CSSImportRule::supports_text() const
+{
+    if (!m_supports)
+        return {};
+    return m_supports->to_string();
+}
+
 }
diff --git a/Libraries/LibWeb/CSS/CSSImportRule.h b/Libraries/LibWeb/CSS/CSSImportRule.h
index bfb6a2dcbe7..e6989188074 100644
--- a/Libraries/LibWeb/CSS/CSSImportRule.h
+++ b/Libraries/LibWeb/CSS/CSSImportRule.h
@@ -33,6 +33,8 @@ public:
     CSSStyleSheet const* loaded_style_sheet() const { return m_style_sheet; }
     CSSStyleSheet* style_sheet_for_bindings() { return m_style_sheet; }
 
+    Optional<String> supports_text() const;
+
 private:
     CSSImportRule(URL::URL, DOM::Document&, RefPtr<Supports>);
 
diff --git a/Libraries/LibWeb/CSS/CSSImportRule.idl b/Libraries/LibWeb/CSS/CSSImportRule.idl
index d474386d076..d6f7446e4af 100644
--- a/Libraries/LibWeb/CSS/CSSImportRule.idl
+++ b/Libraries/LibWeb/CSS/CSSImportRule.idl
@@ -9,5 +9,5 @@ interface CSSImportRule : CSSRule {
     // FIXME: [SameObject, PutForwards=mediaText] readonly attribute MediaList media;
     [SameObject, ImplementedAs=style_sheet_for_bindings] readonly attribute CSSStyleSheet? styleSheet;
     [FIXME] readonly attribute CSSOMString? layerName;
-    [FIXME] readonly attribute CSSOMString? supportsText;
+    readonly attribute CSSOMString? supportsText;
 };
diff --git a/Libraries/LibWeb/CSS/Parser/Parser.cpp b/Libraries/LibWeb/CSS/Parser/Parser.cpp
index f54ed099c31..f01ec0aa5ff 100644
--- a/Libraries/LibWeb/CSS/Parser/Parser.cpp
+++ b/Libraries/LibWeb/CSS/Parser/Parser.cpp
@@ -291,9 +291,11 @@ OwnPtr<BooleanExpression> Parser::parse_supports_feature(TokenStream<ComponentVa
         // FIXME: Parsing and then converting back to a string is weird.
         if (auto declaration = consume_a_declaration(block_tokens); declaration.has_value()) {
             transaction.commit();
-            return Supports::Declaration::create(
+            auto supports_declaration = Supports::Declaration::create(
                 declaration->to_string(),
                 convert_to_style_property(*declaration).has_value());
+
+            return BooleanExpressionInParens::create(supports_declaration.release_nonnull<BooleanExpression>());
         }
     }
 
diff --git a/Libraries/LibWeb/CSS/Supports.cpp b/Libraries/LibWeb/CSS/Supports.cpp
index 99112242623..09ef0411099 100644
--- a/Libraries/LibWeb/CSS/Supports.cpp
+++ b/Libraries/LibWeb/CSS/Supports.cpp
@@ -22,7 +22,7 @@ MatchResult Supports::Declaration::evaluate(HTML::Window const*) const
 
 String Supports::Declaration::to_string() const
 {
-    return MUST(String::formatted("({})", m_declaration));
+    return m_declaration;
 }
 
 void Supports::Declaration::dump(StringBuilder& builder, int indent_levels) const
diff --git a/Tests/LibWeb/Text/expected/css/CSSImportRule-supportsText.txt b/Tests/LibWeb/Text/expected/css/CSSImportRule-supportsText.txt
new file mode 100644
index 00000000000..52162806d0d
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/css/CSSImportRule-supportsText.txt
@@ -0,0 +1,4 @@
+cssText: @import url("https://something.invalid/") supports(foo: bar);
+supportsText: foo: bar
+cssText: @import url("https://something.invalid/") supports((display: block) and (foo: bar));
+supportsText: (display: block) and (foo: bar)
diff --git a/Tests/LibWeb/Text/input/css/CSSImportRule-supportsText.html b/Tests/LibWeb/Text/input/css/CSSImportRule-supportsText.html
new file mode 100644
index 00000000000..6704b7af171
--- /dev/null
+++ b/Tests/LibWeb/Text/input/css/CSSImportRule-supportsText.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<style>
+    @import url("https://something.invalid") supports(foo: bar);
+    @import url("https://something.invalid") supports((display: block) and (foo: bar));
+</style>
+<script src="../include.js"></script>
+<script>
+    test(() => {
+        function printImportRule(importRule) {
+            println(`cssText: ${importRule.cssText}`);
+            println(`supportsText: ${importRule.supportsText}`);
+        }
+
+        printImportRule(document.styleSheets[0].cssRules[0]);
+        printImportRule(document.styleSheets[0].cssRules[1]);
+    });
+</script>