LibWeb/CSS: Move PageSelector into its own files

The main motivation here is that the CSS Parser needs to know about
PageSelectorList so that we can parse one in
`CSSPageRule::set_selector_text()`. Including all of `CSSPageRule.h`
there would pull in a lot of other headers that aren't needed.

Libraries/LibWeb/CMakeLists.txt

@@ -116,6 +116,7 @@ set(SOURCES
     CSS/MediaQueryList.cpp
     CSS/MediaQueryListEvent.cpp
     CSS/Number.cpp
+    CSS/PageSelector.cpp
     CSS/ParsedFontFace.cpp
     CSS/Parser/ComponentValue.cpp
     CSS/Parser/DescriptorParsing.cpp

Libraries/LibWeb/CSS/CSSPageRule.cpp

@@ -15,50 +15,6 @@ namespace Web::CSS {
 
 GC_DEFINE_ALLOCATOR(CSSPageRule);
 
-Optional<PagePseudoClass> page_pseudo_class_from_string(StringView input)
-{
-    if (input.equals_ignoring_ascii_case("blank"sv))
-        return PagePseudoClass::Blank;
-    if (input.equals_ignoring_ascii_case("first"sv))
-        return PagePseudoClass::First;
-    if (input.equals_ignoring_ascii_case("left"sv))
-        return PagePseudoClass::Left;
-    if (input.equals_ignoring_ascii_case("right"sv))
-        return PagePseudoClass::Right;
-    return {};
-}
-
-StringView to_string(PagePseudoClass pseudo_class)
-{
-    switch (pseudo_class) {
-    case PagePseudoClass::Blank:
-        return "blank"sv;
-    case PagePseudoClass::First:
-        return "first"sv;
-    case PagePseudoClass::Left:
-        return "left"sv;
-    case PagePseudoClass::Right:
-        return "right"sv;
-    }
-    VERIFY_NOT_REACHED();
-}
-
-PageSelector::PageSelector(Optional<FlyString> name, Vector<PagePseudoClass> pseudo_classes)
-    : m_name(move(name))
-    , m_pseudo_classes(move(pseudo_classes))
-{
-}
-
-String PageSelector::serialize() const
-{
-    StringBuilder builder;
-    if (m_name.has_value())
-        builder.append(m_name.value());
-    for (auto pseudo_class : m_pseudo_classes)
-        builder.appendff(":{}", to_string(pseudo_class));
-    return builder.to_string_without_validation();
-}
-
 GC::Ref<CSSPageRule> CSSPageRule::create(JS::Realm& realm, PageSelectorList&& selectors, GC::Ref<CSSPageDescriptors> style, CSSRuleList& rules)
 {
     return realm.create<CSSPageRule>(realm, move(selectors), style, rules);

Libraries/LibWeb/CSS/CSSPageRule.h

@@ -8,32 +8,10 @@
 
 #include <LibWeb/CSS/CSSGroupingRule.h>
 #include <LibWeb/CSS/CSSPageDescriptors.h>
+#include <LibWeb/CSS/PageSelector.h>
 
 namespace Web::CSS {
 
-enum class PagePseudoClass : u8 {
-    Left,
-    Right,
-    First,
-    Blank,
-};
-Optional<PagePseudoClass> page_pseudo_class_from_string(StringView);
-StringView to_string(PagePseudoClass);
-
-class PageSelector {
-public:
-    PageSelector(Optional<FlyString> name, Vector<PagePseudoClass>);
-
-    Optional<FlyString> name() const { return m_name; }
-    Vector<PagePseudoClass> const& pseudo_classes() const { return m_pseudo_classes; }
-    String serialize() const;
-
-private:
-    Optional<FlyString> m_name;
-    Vector<PagePseudoClass> m_pseudo_classes;
-};
-using PageSelectorList = Vector<PageSelector>;
-
 // https://drafts.csswg.org/css-page-3/#at-ruledef-page
 class CSSPageRule final : public CSSGroupingRule {
     WEB_PLATFORM_OBJECT(CSSPageRule, CSSGroupingRule);

Libraries/LibWeb/CSS/PageSelector.cpp

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/CSS/PageSelector.h>
+
+namespace Web::CSS {
+
+Optional<PagePseudoClass> page_pseudo_class_from_string(StringView input)
+{
+    if (input.equals_ignoring_ascii_case("blank"sv))
+        return PagePseudoClass::Blank;
+    if (input.equals_ignoring_ascii_case("first"sv))
+        return PagePseudoClass::First;
+    if (input.equals_ignoring_ascii_case("left"sv))
+        return PagePseudoClass::Left;
+    if (input.equals_ignoring_ascii_case("right"sv))
+        return PagePseudoClass::Right;
+    return {};
+}
+
+StringView to_string(PagePseudoClass pseudo_class)
+{
+    switch (pseudo_class) {
+    case PagePseudoClass::Blank:
+        return "blank"sv;
+    case PagePseudoClass::First:
+        return "first"sv;
+    case PagePseudoClass::Left:
+        return "left"sv;
+    case PagePseudoClass::Right:
+        return "right"sv;
+    }
+    VERIFY_NOT_REACHED();
+}
+
+PageSelector::PageSelector(Optional<FlyString> name, Vector<PagePseudoClass> pseudo_classes)
+    : m_name(move(name))
+    , m_pseudo_classes(move(pseudo_classes))
+{
+}
+
+String PageSelector::serialize() const
+{
+    StringBuilder builder;
+    if (m_name.has_value())
+        builder.append(m_name.value());
+    for (auto pseudo_class : m_pseudo_classes)
+        builder.appendff(":{}", to_string(pseudo_class));
+    return builder.to_string_without_validation();
+}
+
+}

Libraries/LibWeb/CSS/PageSelector.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/FlyString.h>
+#include <AK/Optional.h>
+#include <AK/Vector.h>
+
+namespace Web::CSS {
+
+enum class PagePseudoClass : u8 {
+    Left,
+    Right,
+    First,
+    Blank,
+};
+Optional<PagePseudoClass> page_pseudo_class_from_string(StringView);
+StringView to_string(PagePseudoClass);
+
+class PageSelector {
+public:
+    PageSelector(Optional<FlyString> name, Vector<PagePseudoClass>);
+
+    Optional<FlyString> name() const { return m_name; }
+    Vector<PagePseudoClass> const& pseudo_classes() const { return m_pseudo_classes; }
+    String serialize() const;
+
+private:
+    Optional<FlyString> m_name;
+    Vector<PagePseudoClass> m_pseudo_classes;
+};
+using PageSelectorList = Vector<PageSelector>;
+
+}