LibWeb/CSS: Implement converting CSSTransformValues to StyleValues

CSSTransformComponents hold other CSSStyleValues as their parameters. We
want to be able to create internal representations from those parameters
without them caring if they would be valid when directly assigned to the
property.

This is a temporary solution to make transform functions work. To be
completely correct, we need to know what is allowed in that context,
along with value ranges - a combination of the contexts we create when
parsing, and when computing calculations. For transform functions, this
doesn't matter, as there's no limit to the range of allowed values.

.github/workflows/js-and-wasm-artifacts.yml

@@ -49,6 +49,19 @@ jobs:
         with:
           ref: ${{ inputs.reference_to_build }}
 
+      - name: 'Determine build commit hash'
+        id: build-commit
+        shell: bash
+        run: |
+          echo "sha=$(git rev-parse HEAD)" >> "${GITHUB_OUTPUT}"
+
+      - name: 'Use latest custom actions'
+        if: ${{ inputs.reference_to_build != '' && github.sha != steps.build-commit.outputs.sha }}
+        shell: bash
+        run: |
+          git fetch origin master
+          git checkout origin/master -- .github/actions
+
       - name: "Set up environment"
         uses: ./.github/actions/setup
         with:
@@ -102,6 +115,17 @@ jobs:
         run: |
           cpack
 
+          # Inject the COMMIT file for older builds (before commit 5c5de0e30e04).
+          for package in ladybird-*.tar.gz; do
+            if ! tar -tzf "${package}" | grep -qx COMMIT; then
+              echo "${{ steps.build-commit.outputs.sha }}" > COMMIT
+              gunzip "${package}"
+              tar --append --file="${package%.gz}" COMMIT
+              gzip "${package%.gz}"
+              rm COMMIT
+            fi
+          done
+
       - name: Save Caches
         uses: ./.github/actions/cache-save
         with:
@@ -115,23 +139,27 @@ jobs:
       - name: Sanity-check the js repl
         shell: bash
         run: |
-          set -e
-          tar -xvzf Build/distribution/ladybird-js-${{ matrix.package_type }}.tar.gz
-          ./bin/js -c "console.log('Hello, World\!');" > js-repl-out.txt
-          if ! grep -q "\"Hello, World\!\"" js-repl-out.txt; then
+          path="Build/distribution/ladybird-js-${{ matrix.package_type }}.tar.gz"
+          if [ -f "${path}" ]; then
+            tar -xvzf "${path}"
+            bin/js -c "console.log('Hello, World\!');" > js-repl-out.txt
+            if ! grep -q "\"Hello, World\!\"" js-repl-out.txt; then
               echo "Sanity check failed: \"Hello, World\!\" not found in output."
               exit 1
+            fi
           fi
 
       - name: Sanity-check the wasm repl
         shell: bash
         run: |
-          set -e
-          tar -xvzf Build/distribution/ladybird-wasm-${{ matrix.package_type }}.tar.gz
-          ./bin/wasm -e run_sanity_check -w ${{ github.workspace }}/Libraries/LibWasm/Tests/CI/ci-sanity-check.wasm > wasm-repl-out.txt
-          if ! grep -q "Hello, World\!" wasm-repl-out.txt; then
+          path="Build/distribution/ladybird-wasm-${{ matrix.package_type }}.tar.gz"
+          if [ -f "${path}" ]; then
+            tar -xvzf "${path}"
+            bin/wasm -e run_sanity_check -w ${{ github.workspace }}/Libraries/LibWasm/Tests/CI/ci-sanity-check.wasm > wasm-repl-out.txt
+            if ! grep -q "Hello, World\!" wasm-repl-out.txt; then
               echo "Sanity check failed: Hello, World\! not found in output."
               exit 1
+            fi
           fi
 
       - name: Upload js package

Libraries/CMakeLists.txt

@@ -1,5 +1,6 @@
 add_subdirectory(LibCompress)
 add_subdirectory(LibCrypto)
+add_subdirectory(LibDatabase)
 add_subdirectory(LibDiff)
 add_subdirectory(LibDNS)
 add_subdirectory(LibGC)

Libraries/LibCore/StandardPaths.cpp

@@ -129,6 +129,27 @@ ByteString StandardPaths::videos_directory()
     return LexicalPath::canonicalized_path(builder.to_byte_string());
 }
 
+ByteString StandardPaths::cache_directory()
+{
+#if defined(AK_OS_WINDOWS) || defined(AK_OS_HAIKU)
+    return user_data_directory();
+#else
+    if (auto cache_directory = get_environment_if_not_empty("XDG_CACHE_HOME"sv); cache_directory.has_value())
+        return LexicalPath::canonicalized_path(*cache_directory);
+
+    StringBuilder builder;
+    builder.append(home_directory());
+
+#    if defined(AK_OS_MACOS)
+    builder.append("/Library/Caches"sv);
+#    else
+    builder.append("/.cache"sv);
+#    endif
+
+    return LexicalPath::canonicalized_path(builder.to_byte_string());
+#endif
+}
+
 ByteString StandardPaths::config_directory()
 {
     StringBuilder builder;

Libraries/LibCore/StandardPaths.h

@@ -22,6 +22,7 @@ public:
     static ByteString pictures_directory();
     static ByteString videos_directory();
     static ByteString tempfile_directory();
+    static ByteString cache_directory();
     static ByteString config_directory();
     static ByteString user_data_directory();
     static Vector<ByteString> system_data_directories();

Libraries/LibCore/System.cpp

@@ -870,4 +870,27 @@ ErrorOr<void> set_close_on_exec(int fd, bool enabled)
     return {};
 }
 
+ErrorOr<size_t> transfer_file_through_pipe(int source_fd, int target_fd, size_t source_offset, size_t source_length)
+{
+#if defined(AK_OS_LINUX)
+    auto sent = ::splice(source_fd, reinterpret_cast<off_t*>(&source_offset), target_fd, nullptr, source_length, SPLICE_F_MOVE | SPLICE_F_NONBLOCK);
+    if (sent < 0)
+        return Error::from_syscall("send_file_to_pipe"sv, errno);
+    return sent;
+#else
+    static auto page_size = PAGE_SIZE;
+
+    // mmap requires the offset to be page-aligned, so we must handle that here.
+    auto aligned_source_offset = (source_offset / page_size) * page_size;
+    auto offset_adjustment = source_offset - aligned_source_offset;
+    auto mapped_source_length = source_length + offset_adjustment;
+
+    // FIXME: We could use MappedFile here if we update it to support offsets and not auto-close the source fd.
+    auto* mapped = TRY(mmap(nullptr, mapped_source_length, PROT_READ, MAP_SHARED, source_fd, aligned_source_offset));
+    ScopeGuard guard { [&]() { (void)munmap(mapped, mapped_source_length); } };
+
+    return TRY(write(target_fd, { static_cast<u8*>(mapped) + offset_adjustment, source_length }));
+#endif
+}
+
 }

Libraries/LibCore/System.h

@@ -190,4 +190,6 @@ bool is_socket(int fd);
 ErrorOr<void> sleep_ms(u32 milliseconds);
 ErrorOr<void> set_close_on_exec(int fd, bool enabled);
 
+ErrorOr<size_t> transfer_file_through_pipe(int source_fd, int target_fd, size_t source_offset, size_t source_length);
+
 }

Libraries/LibCore/SystemWindows.cpp

@@ -403,4 +403,14 @@ ErrorOr<void> kill(pid_t pid, int signal)
     return {};
 }
 
+ErrorOr<size_t> transfer_file_through_pipe(int source_fd, int target_fd, size_t source_offset, size_t source_length)
+{
+    (void)source_fd;
+    (void)target_fd;
+    (void)source_offset;
+    (void)source_length;
+
+    return Error::from_string_literal("FIXME: Implement System::transfer_file_through_pipe on Windows (for HTTP disk cache)");
+}
+
 }

Libraries/LibDatabase/CMakeLists.txt

@@ -0,0 +1,8 @@
+set(SOURCES
+    Database.cpp
+)
+
+find_package(SQLite3 REQUIRED)
+
+ladybird_lib(LibDatabase database EXPLICIT_SYMBOL_EXPORT)
+target_link_libraries(LibDatabase PRIVATE LibCore SQLite::SQLite3)

Libraries/LibDatabase/Database.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022-2024, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2022-2025, Tim Flynn <trflynn89@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -8,12 +8,11 @@
 #include <AK/String.h>
 #include <AK/Time.h>
 #include <LibCore/Directory.h>
-#include <LibCore/StandardPaths.h>
-#include <LibWebView/Database.h>
+#include <LibDatabase/Database.h>
 
 #include <sqlite3.h>
 
-namespace WebView {
+namespace Database {
 
 static constexpr StringView sql_error(int error_code)
 {
@@ -39,13 +38,25 @@ static constexpr StringView sql_error(int error_code)
         }                                                                                                          \
     })
 
-ErrorOr<NonnullRefPtr<Database>> Database::create()
-{
-    // FIXME: Move this to a generic "Ladybird data directory" helper.
-    auto database_path = ByteString::formatted("{}/Ladybird", Core::StandardPaths::user_data_directory());
-    TRY(Core::Directory::create(database_path, Core::Directory::CreateDirectories::Yes));
+#define ENUMERATE_SQL_TYPES              \
+    __ENUMERATE_TYPE(String)             \
+    __ENUMERATE_TYPE(UnixDateTime)       \
+    __ENUMERATE_TYPE(i8)                 \
+    __ENUMERATE_TYPE(i16)                \
+    __ENUMERATE_TYPE(i32)                \
+    __ENUMERATE_TYPE(long)               \
+    __ENUMERATE_TYPE(long long)          \
+    __ENUMERATE_TYPE(u8)                 \
+    __ENUMERATE_TYPE(u16)                \
+    __ENUMERATE_TYPE(u32)                \
+    __ENUMERATE_TYPE(unsigned long)      \
+    __ENUMERATE_TYPE(unsigned long long) \
+    __ENUMERATE_TYPE(bool)
 
-    auto database_file = ByteString::formatted("{}/Ladybird.db", database_path);
+ErrorOr<NonnullRefPtr<Database>> Database::create(ByteString const& directory, StringView name)
+{
+    TRY(Core::Directory::create(directory, Core::Directory::CreateDirectories::Yes));
+    auto database_file = ByteString::formatted("{}/{}.db", directory, name);
 
     sqlite3* m_database { nullptr };
     SQL_TRY(sqlite3_open(database_file.characters(), &m_database));
@@ -67,7 +78,7 @@ Database::~Database()
     sqlite3_close(m_database);
 }
 
-ErrorOr<Database::StatementID> Database::prepare_statement(StringView statement)
+ErrorOr<StatementID> Database::prepare_statement(StringView statement)
 {
     sqlite3_stmt* prepared_statement { nullptr };
     SQL_TRY(sqlite3_prepare_v2(m_database, statement.characters_without_null_termination(), static_cast<int>(statement.length()), &prepared_statement, nullptr));
@@ -111,18 +122,21 @@ void Database::apply_placeholder(StatementID statement_id, int index, ValueType
         StringView string { value };
         SQL_MUST(sqlite3_bind_text(statement, index, string.characters_without_null_termination(), static_cast<int>(string.length()), SQLITE_TRANSIENT));
     } else if constexpr (IsSame<ValueType, UnixDateTime>) {
-        SQL_MUST(sqlite3_bind_int64(statement, index, value.offset_to_epoch().to_milliseconds()));
-    } else if constexpr (IsSame<ValueType, int>) {
-        SQL_MUST(sqlite3_bind_int(statement, index, value));
-    } else if constexpr (IsSame<ValueType, bool>) {
-        SQL_MUST(sqlite3_bind_int(statement, index, static_cast<int>(value)));
+        apply_placeholder(statement_id, index, value.offset_to_epoch().to_milliseconds());
+    } else if constexpr (IsIntegral<ValueType>) {
+        if constexpr (sizeof(ValueType) <= sizeof(int))
+            SQL_MUST(sqlite3_bind_int(statement, index, static_cast<int>(value)));
+        else
+            SQL_MUST(sqlite3_bind_int64(statement, index, static_cast<sqlite3_int64>(value)));
+    } else {
+        static_assert(DependentFalse<ValueType>);
     }
 }
 
-template void Database::apply_placeholder(StatementID, int, String const&);
-template void Database::apply_placeholder(StatementID, int, UnixDateTime const&);
-template void Database::apply_placeholder(StatementID, int, int const&);
-template void Database::apply_placeholder(StatementID, int, bool const&);
+#define __ENUMERATE_TYPE(type) \
+    template DATABASE_API void Database::apply_placeholder(StatementID, int, type const&);
+ENUMERATE_SQL_TYPES
+#undef __ENUMERATE_TYPE
 
 template<typename ValueType>
 ValueType Database::result_column(StatementID statement_id, int column)
@@ -133,20 +147,21 @@ ValueType Database::result_column(StatementID statement_id, int column)
         auto const* text = reinterpret_cast<char const*>(sqlite3_column_text(statement, column));
         return MUST(String::from_utf8(StringView { text, strlen(text) }));
     } else if constexpr (IsSame<ValueType, UnixDateTime>) {
-        auto milliseconds = sqlite3_column_int64(statement, column);
+        auto milliseconds = result_column<sqlite3_int64>(statement_id, column);
         return UnixDateTime::from_milliseconds_since_epoch(milliseconds);
-    } else if constexpr (IsSame<ValueType, int>) {
-        return sqlite3_column_int(statement, column);
-    } else if constexpr (IsSame<ValueType, bool>) {
-        return static_cast<bool>(sqlite3_column_int(statement, column));
+    } else if constexpr (IsIntegral<ValueType>) {
+        if constexpr (sizeof(ValueType) <= sizeof(int))
+            return static_cast<ValueType>(sqlite3_column_int(statement, column));
+        else
+            return static_cast<ValueType>(sqlite3_column_int64(statement, column));
+    } else {
+        static_assert(DependentFalse<ValueType>);
     }
-
-    VERIFY_NOT_REACHED();
 }
 
-template String Database::result_column(StatementID, int);
-template UnixDateTime Database::result_column(StatementID, int);
-template int Database::result_column(StatementID, int);
-template bool Database::result_column(StatementID, int);
+#define __ENUMERATE_TYPE(type) \
+    template DATABASE_API type Database::result_column(StatementID, int);
+ENUMERATE_SQL_TYPES
+#undef __ENUMERATE_TYPE
 
 }

Libraries/LibDatabase/Database.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022-2024, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2022-2025, Tim Flynn <trflynn89@ladybird.org>
  * Copyright (c) 2023, Jelle Raaijmakers <jelle@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -13,19 +13,18 @@
 #include <AK/RefCounted.h>
 #include <AK/StringView.h>
 #include <AK/Vector.h>
-#include <LibWebView/Forward.h>
+#include <LibDatabase/Forward.h>
 
 struct sqlite3;
 struct sqlite3_stmt;
 
-namespace WebView {
+namespace Database {
 
-class WEBVIEW_API Database : public RefCounted<Database> {
+class DATABASE_API Database : public RefCounted<Database> {
 public:
-    static ErrorOr<NonnullRefPtr<Database>> create();
+    static ErrorOr<NonnullRefPtr<Database>> create(ByteString const& directory, StringView name);
     ~Database();
 
-    using StatementID = size_t;
     using OnResult = Function<void(StatementID)>;
 
     ErrorOr<StatementID> prepare_statement(StringView statement);

Libraries/LibDatabase/Forward.h

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+#include <LibDatabase/Export.h>
+
+namespace Database {
+
+class Database;
+
+using StatementID = size_t;
+
+}

Libraries/LibGfx/Bitmap.cpp

@@ -10,6 +10,11 @@
 #include <AK/Checked.h>
 #include <LibGfx/Bitmap.h>
 #include <LibGfx/ShareableBitmap.h>
+#include <LibGfx/SkiaUtils.h>
+
+#include <core/SkBitmap.h>
+#include <core/SkColorSpace.h>
+#include <core/SkImage.h>
 #include <errno.h>
 
 #ifdef AK_OS_MACOS
@@ -184,6 +189,24 @@ ErrorOr<NonnullRefPtr<Gfx::Bitmap>> Bitmap::cropped(Gfx::IntRect crop, Gfx::Colo
     return new_bitmap;
 }
 
+ErrorOr<NonnullRefPtr<Bitmap>> Bitmap::scaled(int const width, int const height, ScalingMode const scaling_mode) const
+{
+    auto const source_info = SkImageInfo::Make(this->width(), this->height(), to_skia_color_type(format()), to_skia_alpha_type(format(), alpha_type()), nullptr);
+    SkPixmap const source_sk_pixmap(source_info, begin(), pitch());
+    SkBitmap source_sk_bitmap;
+    source_sk_bitmap.installPixels(source_sk_pixmap);
+    source_sk_bitmap.setImmutable();
+
+    auto scaled_bitmap = TRY(Gfx::Bitmap::create(format(), alpha_type(), { width, height }));
+    auto const scaled_info = SkImageInfo::Make(scaled_bitmap->width(), scaled_bitmap->height(), to_skia_color_type(scaled_bitmap->format()), to_skia_alpha_type(scaled_bitmap->format(), scaled_bitmap->alpha_type()), nullptr);
+    SkPixmap const scaled_sk_pixmap(scaled_info, scaled_bitmap->begin(), scaled_bitmap->pitch());
+
+    sk_sp<SkImage> source_sk_image = source_sk_bitmap.asImage();
+    if (!source_sk_image->scalePixels(scaled_sk_pixmap, to_skia_sampling_options(scaling_mode)))
+        return Error::from_string_literal("Unable to scale pixels for bitmap");
+    return scaled_bitmap;
+}
+
 ErrorOr<NonnullRefPtr<Bitmap>> Bitmap::to_bitmap_backed_by_anonymous_buffer() const
 {
     if (m_buffer.is_valid()) {

Libraries/LibGfx/Bitmap.h

@@ -13,6 +13,7 @@
 #include <LibGfx/Color.h>
 #include <LibGfx/Forward.h>
 #include <LibGfx/Rect.h>
+#include <LibGfx/ScalingMode.h>
 
 namespace Gfx {
 
@@ -74,6 +75,8 @@ public:
     ErrorOr<NonnullRefPtr<Gfx::Bitmap>> clone() const;
 
     ErrorOr<NonnullRefPtr<Gfx::Bitmap>> cropped(Gfx::IntRect, Gfx::Color outside_color = Gfx::Color::Black) const;
+    ErrorOr<NonnullRefPtr<Bitmap>> scaled(int width, int height, ScalingMode scaling_mode) const;
+
     ErrorOr<NonnullRefPtr<Gfx::Bitmap>> to_bitmap_backed_by_anonymous_buffer() const;
 
     [[nodiscard]] ShareableBitmap to_shareable_bitmap() const;

Libraries/LibRequests/NetworkError.h

@@ -21,6 +21,7 @@ enum class NetworkError {
     MalformedUrl,
     InvalidContentEncoding,
     RequestServerDied,
+    CacheReadFailed,
     Unknown,
 };
 
@@ -47,6 +48,8 @@ constexpr StringView network_error_to_string(NetworkError network_error)
         return "Response could not be decoded with its Content-Encoding"sv;
     case NetworkError::RequestServerDied:
         return "RequestServer is currently unavailable"sv;
+    case NetworkError::CacheReadFailed:
+        return "RequestServer encountered an error reading a cached HTTP response"sv;
     case NetworkError::Unknown:
         return "An unexpected network error occurred"sv;
     }

Libraries/LibWeb/CSS/CSSImageValue.cpp

@@ -40,7 +40,7 @@ WebIDL::ExceptionOr<String> CSSImageValue::to_string() const
 }
 
 // https://drafts.css-houdini.org/css-typed-om-1/#create-an-internal-representation
-WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSImageValue::create_an_internal_representation(PropertyNameAndID const& property) const
+WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSImageValue::create_an_internal_representation(PropertyNameAndID const& property, PerformTypeCheck perform_type_check) const
 {
     // If value is a CSSStyleValue subclass,
     //     If value does not match the grammar of a list-valued property iteration of property, throw a TypeError.
@@ -53,7 +53,7 @@ WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSImageValue::create_an_in
         }
         return property_accepts_type(property.id(), ValueType::Image);
     }();
-    if (!matches_grammar) {
+    if (perform_type_check == PerformTypeCheck::Yes && !matches_grammar) {
         return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, MUST(String::formatted("Property '{}' does not accept <image>", property.name())) };
     }
 

Libraries/LibWeb/CSS/CSSImageValue.h

@@ -21,7 +21,7 @@ public:
     virtual ~CSSImageValue() override = default;
 
     virtual WebIDL::ExceptionOr<String> to_string() const override;
-    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&) const override;
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&, PerformTypeCheck) const override;
 
 private:
     explicit CSSImageValue(JS::Realm&, NonnullRefPtr<StyleValue const> source_value);

Libraries/LibWeb/CSS/CSSKeywordValue.cpp

@@ -68,7 +68,7 @@ WebIDL::ExceptionOr<String> CSSKeywordValue::to_string() const
 }
 
 // https://drafts.css-houdini.org/css-typed-om-1/#create-an-internal-representation
-WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSKeywordValue::create_an_internal_representation(PropertyNameAndID const& property) const
+WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSKeywordValue::create_an_internal_representation(PropertyNameAndID const& property, PerformTypeCheck perform_type_check) const
 {
     // If value is a CSSStyleValue subclass,
     //     If value does not match the grammar of a list-valued property iteration of property, throw a TypeError.
@@ -87,7 +87,7 @@ WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSKeywordValue::create_an_
         auto keyword = keyword_from_string(m_value);
         return keyword.has_value() && property_accepts_keyword(property.id(), keyword.value());
     }();
-    if (!matches_grammar) {
+    if (perform_type_check == PerformTypeCheck::Yes && !matches_grammar) {
         return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, MUST(String::formatted("Property '{}' does not accept the keyword '{}'", property.name(), m_value)) };
     }
 

Libraries/LibWeb/CSS/CSSKeywordValue.h

@@ -29,7 +29,7 @@ public:
     WebIDL::ExceptionOr<void> set_value(FlyString value);
 
     virtual WebIDL::ExceptionOr<String> to_string() const override;
-    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&) const override;
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&, PerformTypeCheck) const override;
 
 private:
     explicit CSSKeywordValue(JS::Realm&, FlyString value);

Libraries/LibWeb/CSS/CSSMathValue.cpp

@@ -26,7 +26,7 @@ void CSSMathValue::initialize(JS::Realm& realm)
 }
 
 // https://drafts.css-houdini.org/css-typed-om-1/#create-an-internal-representation
-WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSMathValue::create_an_internal_representation(PropertyNameAndID const& property) const
+WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSMathValue::create_an_internal_representation(PropertyNameAndID const& property, PerformTypeCheck perform_type_check) const
 {
     // If value is a CSSStyleValue subclass,
     //     If value does not match the grammar of a list-valued property iteration of property, throw a TypeError.
@@ -59,7 +59,7 @@ WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSMathValue::create_an_int
         return false;
     }();
 
-    if (!matches)
+    if (perform_type_check == PerformTypeCheck::Yes && !matches)
         return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, "Property does not accept values of this type."sv };
 
     return CalculatedStyleValue::create(TRY(create_calculation_node(context)), type(), move(context));

Libraries/LibWeb/CSS/CSSMathValue.h

@@ -32,7 +32,7 @@ public:
     };
     virtual String serialize_math_value(Nested, Parens) const = 0;
 
-    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&) const final override;
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&, PerformTypeCheck) const final override;
 
 protected:
     explicit CSSMathValue(JS::Realm&, Bindings::CSSMathOperator, NumericType);

Libraries/LibWeb/CSS/CSSMatrixComponent.cpp

@@ -7,6 +7,9 @@
 #include "CSSMatrixComponent.h"
 #include <LibWeb/Bindings/CSSMatrixComponentPrototype.h>
 #include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/CSS/PropertyNameAndID.h>
+#include <LibWeb/CSS/StyleValues/NumberStyleValue.h>
+#include <LibWeb/CSS/StyleValues/TransformationStyleValue.h>
 #include <LibWeb/Geometry/DOMMatrix.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
 
@@ -82,4 +85,39 @@ WebIDL::ExceptionOr<void> CSSMatrixComponent::set_matrix(GC::Ref<Geometry::DOMMa
     return {};
 }
 
+WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> CSSMatrixComponent::create_style_value(PropertyNameAndID const& property) const
+{
+    if (is_2d()) {
+        return TransformationStyleValue::create(property.id(), TransformFunction::Matrix,
+            {
+                NumberStyleValue::create(m_matrix->a()),
+                NumberStyleValue::create(m_matrix->b()),
+                NumberStyleValue::create(m_matrix->c()),
+                NumberStyleValue::create(m_matrix->d()),
+                NumberStyleValue::create(m_matrix->e()),
+                NumberStyleValue::create(m_matrix->f()),
+            });
+    }
+
+    return TransformationStyleValue::create(property.id(), TransformFunction::Matrix3d,
+        {
+            NumberStyleValue::create(m_matrix->m11()),
+            NumberStyleValue::create(m_matrix->m12()),
+            NumberStyleValue::create(m_matrix->m13()),
+            NumberStyleValue::create(m_matrix->m14()),
+            NumberStyleValue::create(m_matrix->m21()),
+            NumberStyleValue::create(m_matrix->m22()),
+            NumberStyleValue::create(m_matrix->m23()),
+            NumberStyleValue::create(m_matrix->m24()),
+            NumberStyleValue::create(m_matrix->m31()),
+            NumberStyleValue::create(m_matrix->m32()),
+            NumberStyleValue::create(m_matrix->m33()),
+            NumberStyleValue::create(m_matrix->m34()),
+            NumberStyleValue::create(m_matrix->m41()),
+            NumberStyleValue::create(m_matrix->m42()),
+            NumberStyleValue::create(m_matrix->m43()),
+            NumberStyleValue::create(m_matrix->m44()),
+        });
+}
+
 }

Libraries/LibWeb/CSS/CSSMatrixComponent.h

@@ -33,6 +33,8 @@ public:
     GC::Ref<Geometry::DOMMatrix> matrix() const { return m_matrix; }
     WebIDL::ExceptionOr<void> set_matrix(GC::Ref<Geometry::DOMMatrix> matrix);
 
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> create_style_value(PropertyNameAndID const&) const override;
+
 private:
     explicit CSSMatrixComponent(JS::Realm&, Is2D, GC::Ref<Geometry::DOMMatrix>);
 

Libraries/LibWeb/CSS/CSSPerspective.cpp

@@ -9,6 +9,8 @@
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/CSS/CSSNumericValue.h>
 #include <LibWeb/CSS/CSSUnitValue.h>
+#include <LibWeb/CSS/PropertyNameAndID.h>
+#include <LibWeb/CSS/StyleValues/TransformationStyleValue.h>
 #include <LibWeb/Geometry/DOMMatrix.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
 
@@ -157,4 +159,12 @@ void CSSPerspective::set_is_2d(bool)
     // The is2D attribute of a CSSPerspective object must, on setting, do nothing.
 }
 
+WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> CSSPerspective::create_style_value(PropertyNameAndID const& property) const
+{
+    auto length = TRY(m_length.visit([&](auto const& value) {
+        return value->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No);
+    }));
+    return TransformationStyleValue::create(property.id(), TransformFunction::Perspective, { move(length) });
+}
+
 }

Libraries/LibWeb/CSS/CSSPerspective.h

@@ -37,6 +37,8 @@ public:
 
     virtual void set_is_2d(bool value) override;
 
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> create_style_value(PropertyNameAndID const&) const override;
+
 private:
     explicit CSSPerspective(JS::Realm&, CSSPerspectiveValueInternal);
 

Libraries/LibWeb/CSS/CSSRotate.cpp

@@ -8,6 +8,8 @@
 #include <LibWeb/Bindings/CSSRotatePrototype.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/CSS/CSSUnitValue.h>
+#include <LibWeb/CSS/PropertyNameAndID.h>
+#include <LibWeb/CSS/StyleValues/TransformationStyleValue.h>
 #include <LibWeb/Geometry/DOMMatrix.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
 
@@ -218,4 +220,22 @@ WebIDL::ExceptionOr<void> CSSRotate::set_angle(GC::Ref<CSSNumericValue> value)
     return {};
 }
 
+WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> CSSRotate::create_style_value(PropertyNameAndID const& property) const
+{
+    if (is_2d()) {
+        return TransformationStyleValue::create(property.id(), TransformFunction::Rotate,
+            {
+                TRY(m_angle->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            });
+    }
+
+    return TransformationStyleValue::create(property.id(), TransformFunction::Rotate3d,
+        {
+            TRY(m_x->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            TRY(m_y->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            TRY(m_z->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            TRY(m_angle->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+        });
+}
+
 }

Libraries/LibWeb/CSS/CSSRotate.h

@@ -36,6 +36,8 @@ public:
     WebIDL::ExceptionOr<void> set_z(CSSNumberish value);
     WebIDL::ExceptionOr<void> set_angle(GC::Ref<CSSNumericValue> value);
 
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> create_style_value(PropertyNameAndID const&) const override;
+
 private:
     explicit CSSRotate(JS::Realm&, Is2D, GC::Ref<CSSNumericValue> x, GC::Ref<CSSNumericValue> y, GC::Ref<CSSNumericValue> z, GC::Ref<CSSNumericValue> angle);
 

Libraries/LibWeb/CSS/CSSScale.cpp

@@ -9,6 +9,8 @@
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/CSS/CSSNumericValue.h>
 #include <LibWeb/CSS/CSSUnitValue.h>
+#include <LibWeb/CSS/PropertyNameAndID.h>
+#include <LibWeb/CSS/StyleValues/TransformationStyleValue.h>
 #include <LibWeb/Geometry/DOMMatrix.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
 
@@ -199,4 +201,22 @@ WebIDL::ExceptionOr<void> CSSScale::set_z(CSSNumberish value)
     return {};
 }
 
+WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> CSSScale::create_style_value(PropertyNameAndID const& property) const
+{
+    if (is_2d()) {
+        return TransformationStyleValue::create(property.id(), TransformFunction::Scale,
+            {
+                TRY(m_x->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+                TRY(m_y->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            });
+    }
+
+    return TransformationStyleValue::create(property.id(), TransformFunction::Scale3d,
+        {
+            TRY(m_x->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            TRY(m_y->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            TRY(m_z->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+        });
+}
+
 }

Libraries/LibWeb/CSS/CSSScale.h

@@ -33,6 +33,8 @@ public:
     WebIDL::ExceptionOr<void> set_y(CSSNumberish value);
     WebIDL::ExceptionOr<void> set_z(CSSNumberish value);
 
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> create_style_value(PropertyNameAndID const&) const override;
+
 private:
     explicit CSSScale(JS::Realm&, Is2D, GC::Ref<CSSNumericValue> x, GC::Ref<CSSNumericValue> y, GC::Ref<CSSNumericValue> z);
 

Libraries/LibWeb/CSS/CSSSkew.cpp

@@ -9,6 +9,8 @@
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/CSS/CSSNumericValue.h>
 #include <LibWeb/CSS/CSSUnitValue.h>
+#include <LibWeb/CSS/PropertyNameAndID.h>
+#include <LibWeb/CSS/StyleValues/TransformationStyleValue.h>
 #include <LibWeb/Geometry/DOMMatrix.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
 
@@ -136,4 +138,13 @@ void CSSSkew::set_is_2d(bool)
     // The is2D attribute of a CSSSkew, CSSSkewX, or CSSSkewY object must, on setting, do nothing.
 }
 
+WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> CSSSkew::create_style_value(PropertyNameAndID const& property) const
+{
+    return TransformationStyleValue::create(property.id(), TransformFunction::Skew,
+        {
+            TRY(m_ax->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            TRY(m_ay->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+        });
+}
+
 }

Libraries/LibWeb/CSS/CSSSkew.h

@@ -32,6 +32,8 @@ public:
 
     virtual void set_is_2d(bool value) override;
 
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> create_style_value(PropertyNameAndID const&) const override;
+
 private:
     explicit CSSSkew(JS::Realm&, GC::Ref<CSSNumericValue> ax, GC::Ref<CSSNumericValue> ay);
 

Libraries/LibWeb/CSS/CSSSkewX.cpp

@@ -9,6 +9,8 @@
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/CSS/CSSNumericValue.h>
 #include <LibWeb/CSS/CSSUnitValue.h>
+#include <LibWeb/CSS/PropertyNameAndID.h>
+#include <LibWeb/CSS/StyleValues/TransformationStyleValue.h>
 #include <LibWeb/Geometry/DOMMatrix.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
 
@@ -106,4 +108,12 @@ void CSSSkewX::set_is_2d(bool)
     // The is2D attribute of a CSSSkewX, CSSSkewXX, or CSSSkewXY object must, on setting, do nothing.
 }
 
+WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> CSSSkewX::create_style_value(PropertyNameAndID const& property) const
+{
+    return TransformationStyleValue::create(property.id(), TransformFunction::SkewX,
+        {
+            TRY(m_ax->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+        });
+}
+
 }

Libraries/LibWeb/CSS/CSSSkewX.h

@@ -30,6 +30,8 @@ public:
 
     virtual void set_is_2d(bool value) override;
 
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> create_style_value(PropertyNameAndID const&) const override;
+
 private:
     explicit CSSSkewX(JS::Realm&, GC::Ref<CSSNumericValue> ax);
 

Libraries/LibWeb/CSS/CSSSkewY.cpp

@@ -9,6 +9,8 @@
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/CSS/CSSNumericValue.h>
 #include <LibWeb/CSS/CSSUnitValue.h>
+#include <LibWeb/CSS/PropertyNameAndID.h>
+#include <LibWeb/CSS/StyleValues/TransformationStyleValue.h>
 #include <LibWeb/Geometry/DOMMatrix.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
 
@@ -106,4 +108,12 @@ void CSSSkewY::set_is_2d(bool)
     // The is2D attribute of a CSSSkewY, CSSSkewYX, or CSSSkewYY object must, on setting, do nothing.
 }
 
+WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> CSSSkewY::create_style_value(PropertyNameAndID const& property) const
+{
+    return TransformationStyleValue::create(property.id(), TransformFunction::SkewY,
+        {
+            TRY(m_ay->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+        });
+}
+
 }

Libraries/LibWeb/CSS/CSSSkewY.h

@@ -30,6 +30,8 @@ public:
 
     virtual void set_is_2d(bool value) override;
 
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> create_style_value(PropertyNameAndID const&) const override;
+
 private:
     explicit CSSSkewY(JS::Realm&, GC::Ref<CSSNumericValue> ay);
 

Libraries/LibWeb/CSS/CSSStyleValue.cpp

@@ -123,7 +123,7 @@ WebIDL::ExceptionOr<String> CSSStyleValue::to_string() const
 }
 
 // https://drafts.css-houdini.org/css-typed-om-1/#create-an-internal-representation
-WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSStyleValue::create_an_internal_representation(PropertyNameAndID const&) const
+WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSStyleValue::create_an_internal_representation(PropertyNameAndID const&, PerformTypeCheck) const
 {
     // If value is a direct CSSStyleValue,
     //     Return value’s associated value.

Libraries/LibWeb/CSS/CSSStyleValue.h

@@ -37,7 +37,12 @@ public:
 
     virtual WebIDL::ExceptionOr<String> to_string() const;
 
-    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&) const;
+    // FIXME: Temporary hack. Really we want to pass something like a CalculationContext with the valid types and ranges.
+    enum class PerformTypeCheck : u8 {
+        No,
+        Yes,
+    };
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&, PerformTypeCheck) const;
 
 protected:
     explicit CSSStyleValue(JS::Realm&);

Libraries/LibWeb/CSS/CSSTransformComponent.h

@@ -31,6 +31,8 @@ public:
 
     virtual WebIDL::ExceptionOr<GC::Ref<Geometry::DOMMatrix>> to_matrix() const = 0;
 
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> create_style_value(PropertyNameAndID const&) const = 0;
+
 protected:
     explicit CSSTransformComponent(JS::Realm&, Is2D is_2d);
 

Libraries/LibWeb/CSS/CSSTransformValue.cpp

@@ -8,6 +8,9 @@
 #include <LibWeb/Bindings/CSSTransformValuePrototype.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/CSS/CSSTransformComponent.h>
+#include <LibWeb/CSS/PropertyNameAndID.h>
+#include <LibWeb/CSS/StyleValues/StyleValueList.h>
+#include <LibWeb/CSS/StyleValues/TransformationStyleValue.h>
 #include <LibWeb/Geometry/DOMMatrix.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
 
@@ -155,4 +158,35 @@ WebIDL::ExceptionOr<String> CSSTransformValue::to_string() const
     return builder.to_string_without_validation();
 }
 
+// https://drafts.css-houdini.org/css-typed-om-1/#create-an-internal-representation
+WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSTransformValue::create_an_internal_representation(PropertyNameAndID const& property, PerformTypeCheck perform_type_check) const
+{
+    // NB: This can become <transform-function> or <transform-list>, and we don't know which is wanted without performing the type checking.
+    //     We can worry about that if and when we ever do have a CSSTransformValue that isn't top-level.
+    VERIFY(perform_type_check == PerformTypeCheck::Yes);
+
+    // If value is a CSSStyleValue subclass,
+    //     If value does not match the grammar of a list-valued property iteration of property, throw a TypeError.
+    //
+    //     If any component of property’s CSS grammar has a limited numeric range, and the corresponding part of value
+    //     is a CSSUnitValue that is outside of that range, replace that value with the result of wrapping it in a
+    //     fresh CSSMathSum whose values internal slot contains only that part of value.
+    //
+    //     Return the value.
+
+    // NB: We match <transform-function> if we have 1 transform. We match <transform-list> always.
+    if (m_transforms.size() == 1 && property_accepts_type(property.id(), ValueType::TransformFunction))
+        return TRY(m_transforms.first()->create_style_value(property));
+
+    if (property_accepts_type(property.id(), ValueType::TransformList)) {
+        StyleValueVector transforms;
+        transforms.ensure_capacity(m_transforms.size());
+        for (auto const transform : m_transforms)
+            transforms.unchecked_append(TRY(transform->create_style_value(property)));
+        return StyleValueList::create(move(transforms), StyleValueList::Separator::Space);
+    }
+
+    return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, "Property does not accept values of this type."sv };
+}
+
 }

Libraries/LibWeb/CSS/CSSTransformValue.h

@@ -32,6 +32,8 @@ public:
 
     virtual WebIDL::ExceptionOr<String> to_string() const override;
 
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&, PerformTypeCheck) const override;
+
 private:
     explicit CSSTransformValue(JS::Realm&, Vector<GC::Ref<CSSTransformComponent>>);
 

Libraries/LibWeb/CSS/CSSTranslate.cpp

@@ -9,6 +9,8 @@
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/CSS/CSSNumericValue.h>
 #include <LibWeb/CSS/CSSUnitValue.h>
+#include <LibWeb/CSS/PropertyNameAndID.h>
+#include <LibWeb/CSS/StyleValues/TransformationStyleValue.h>
 #include <LibWeb/Geometry/DOMMatrix.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
 
@@ -178,4 +180,22 @@ WebIDL::ExceptionOr<void> CSSTranslate::set_z(GC::Ref<CSSNumericValue> z)
     return {};
 }
 
+WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> CSSTranslate::create_style_value(PropertyNameAndID const& property) const
+{
+    if (is_2d()) {
+        return TransformationStyleValue::create(property.id(), TransformFunction::Translate,
+            {
+                TRY(m_x->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+                TRY(m_y->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            });
+    }
+
+    return TransformationStyleValue::create(property.id(), TransformFunction::Translate3d,
+        {
+            TRY(m_x->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            TRY(m_y->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+            TRY(m_z->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::No)),
+        });
+}
+
 }

Libraries/LibWeb/CSS/CSSTranslate.h

@@ -32,6 +32,8 @@ public:
     WebIDL::ExceptionOr<void> set_y(GC::Ref<CSSNumericValue> value);
     WebIDL::ExceptionOr<void> set_z(GC::Ref<CSSNumericValue> value);
 
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<TransformationStyleValue const>> create_style_value(PropertyNameAndID const&) const override;
+
 private:
     explicit CSSTranslate(JS::Realm&, Is2D, GC::Ref<CSSNumericValue> x, GC::Ref<CSSNumericValue> y, GC::Ref<CSSNumericValue> z);
 

Libraries/LibWeb/CSS/CSSUnitValue.cpp

@@ -326,7 +326,7 @@ static Optional<CalculationNode::NumericValue> create_numeric_value(double value
 }
 
 // https://drafts.css-houdini.org/css-typed-om-1/#create-an-internal-representation
-WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSUnitValue::create_an_internal_representation(PropertyNameAndID const& property) const
+WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSUnitValue::create_an_internal_representation(PropertyNameAndID const& property, PerformTypeCheck perform_type_check) const
 {
     // If value is a CSSStyleValue subclass,
     //     If value does not match the grammar of a list-valued property iteration of property, throw a TypeError.
@@ -338,7 +338,7 @@ WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSUnitValue::create_an_int
     //     Return the value.
 
     // NB: We store all custom properties as UnresolvedStyleValue, so we always need to create one here.
-    if (property.is_custom_property()) {
+    if (perform_type_check == PerformTypeCheck::Yes && property.is_custom_property()) {
         auto token = [this]() {
             if (m_unit == "number"_fly_string)
                 return Parser::Token::create_number(Number { Number::Type::Number, m_value });
@@ -361,6 +361,35 @@ WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSUnitValue::create_an_int
         return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, MUST(String::formatted("Unrecognized unit '{}'.", m_unit)) };
     }
 
+    if (perform_type_check == PerformTypeCheck::No) {
+        return value->visit(
+                        [&](Number const& number) -> RefPtr<StyleValue const> {
+                            return NumberStyleValue::create(number.value());
+                        },
+                        [&](Percentage const& percentage) -> RefPtr<StyleValue const> {
+                            return PercentageStyleValue::create(percentage);
+                        },
+                        [&](Angle const& angle) -> RefPtr<StyleValue const> {
+                            return AngleStyleValue::create(angle);
+                        },
+                        [&](Flex const& flex) -> RefPtr<StyleValue const> {
+                            return FlexStyleValue::create(flex);
+                        },
+                        [&](Frequency const& frequency) -> RefPtr<StyleValue const> {
+                            return FrequencyStyleValue::create(frequency);
+                        },
+                        [&](Length const& length) -> RefPtr<StyleValue const> {
+                            return LengthStyleValue::create(length);
+                        },
+                        [&](Resolution const& resolution) -> RefPtr<StyleValue const> {
+                            return ResolutionStyleValue::create(resolution);
+                        },
+                        [&](Time const& time) -> RefPtr<StyleValue const> {
+                            return TimeStyleValue::create(time);
+                        })
+            .release_nonnull();
+    }
+
     // FIXME: Check types allowed by registered custom properties.
     auto style_value = value->visit(
         [&](Number const& number) -> RefPtr<StyleValue const> {

Libraries/LibWeb/CSS/CSSUnitValue.h

@@ -35,7 +35,7 @@ public:
     virtual bool is_equal_numeric_value(GC::Ref<CSSNumericValue> other) const override;
     virtual Optional<SumValue> create_a_sum_value() const override;
 
-    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&) const override;
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&, PerformTypeCheck) const override;
     virtual WebIDL::ExceptionOr<NonnullRefPtr<CalculationNode const>> create_calculation_node(CalculationContext const&) const override;
 
 private:

Libraries/LibWeb/CSS/CSSUnparsedValue.cpp

@@ -168,7 +168,7 @@ WebIDL::ExceptionOr<String> CSSUnparsedValue::to_string() const
 }
 
 // https://drafts.css-houdini.org/css-typed-om-1/#create-an-internal-representation
-WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSUnparsedValue::create_an_internal_representation(PropertyNameAndID const&) const
+WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSUnparsedValue::create_an_internal_representation(PropertyNameAndID const&, PerformTypeCheck) const
 {
     // If value is a CSSStyleValue subclass,
     //     If value does not match the grammar of a list-valued property iteration of property, throw a TypeError.

Libraries/LibWeb/CSS/CSSUnparsedValue.h

@@ -31,7 +31,7 @@ public:
     virtual WebIDL::ExceptionOr<void> set_value_of_new_indexed_property(u32, JS::Value) override;
 
     virtual WebIDL::ExceptionOr<String> to_string() const override;
-    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&) const override;
+    virtual WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_representation(PropertyNameAndID const&, PerformTypeCheck) const override;
 
 private:
     explicit CSSUnparsedValue(JS::Realm&, Vector<CSSUnparsedSegment>);

Libraries/LibWeb/CSS/Parser/Parser.h

@@ -484,7 +484,8 @@ private:
     RefPtr<StyleValue const> parse_rotate_value(TokenStream<ComponentValue>&);
     RefPtr<StyleValue const> parse_stroke_dasharray_value(TokenStream<ComponentValue>&);
     RefPtr<StyleValue const> parse_easing_value(TokenStream<ComponentValue>&);
-    RefPtr<StyleValue const> parse_transform_value(TokenStream<ComponentValue>&);
+    RefPtr<StyleValue const> parse_transform_function_value(TokenStream<ComponentValue>&);
+    RefPtr<StyleValue const> parse_transform_list_value(TokenStream<ComponentValue>&);
     RefPtr<StyleValue const> parse_transform_origin_value(TokenStream<ComponentValue>&);
     RefPtr<StyleValue const> parse_transition_value(TokenStream<ComponentValue>&);
     RefPtr<StyleValue const> parse_transition_property_value(TokenStream<ComponentValue>&);

Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp

@@ -178,6 +178,10 @@ Optional<Parser::PropertyAndValue> Parser::parse_css_value_for_properties(Readon
         return parsed.release_value();
     if (auto parsed = parse_for_type(ValueType::String); parsed.has_value())
         return parsed.release_value();
+    if (auto parsed = parse_for_type(ValueType::TransformFunction); parsed.has_value())
+        return parsed.release_value();
+    if (auto parsed = parse_for_type(ValueType::TransformList); parsed.has_value())
+        return parsed.release_value();
     if (auto parsed = parse_for_type(ValueType::Url); parsed.has_value())
         return parsed.release_value();
 
@@ -802,10 +806,6 @@ Parser::ParseErrorOr<NonnullRefPtr<StyleValue const>> Parser::parse_css_value(Pr
         if (auto parsed_value = parse_touch_action_value(tokens); parsed_value && !tokens.has_next_token())
             return parsed_value.release_nonnull();
         return ParseError::SyntaxError;
-    case PropertyID::Transform:
-        if (auto parsed_value = parse_transform_value(tokens); parsed_value && !tokens.has_next_token())
-            return parsed_value.release_nonnull();
-        return ParseError::SyntaxError;
     case PropertyID::TransformOrigin:
         if (auto parsed_value = parse_transform_origin_value(tokens); parsed_value && !tokens.has_next_token())
             return parsed_value.release_nonnull();
@@ -4913,119 +4913,6 @@ RefPtr<StyleValue const> Parser::parse_touch_action_value(TokenStream<ComponentV
     return StyleValueList::create(move(parsed_values), StyleValueList::Separator::Space);
 }
 
-// https://www.w3.org/TR/css-transforms-1/#transform-property
-RefPtr<StyleValue const> Parser::parse_transform_value(TokenStream<ComponentValue>& tokens)
-{
-    // <transform> = none | <transform-list>
-    // <transform-list> = <transform-function>+
-
-    if (auto none = parse_all_as_single_keyword_value(tokens, Keyword::None))
-        return none;
-
-    StyleValueVector transformations;
-    auto transaction = tokens.begin_transaction();
-    while (tokens.has_next_token()) {
-        auto const& part = tokens.consume_a_token();
-        if (!part.is_function())
-            return nullptr;
-        auto maybe_function = transform_function_from_string(part.function().name);
-        if (!maybe_function.has_value())
-            return nullptr;
-
-        auto context_guard = push_temporary_value_parsing_context(FunctionContext { part.function().name });
-
-        auto function = maybe_function.release_value();
-        auto function_metadata = transform_function_metadata(function);
-
-        auto function_tokens = TokenStream { part.function().value };
-        auto arguments = parse_a_comma_separated_list_of_component_values(function_tokens);
-
-        if (arguments.size() > function_metadata.parameters.size()) {
-            ErrorReporter::the().report(InvalidValueError {
-                .value_type = "<transform-function>"_fly_string,
-                .value_string = part.function().original_source_text(),
-                .description = MUST(String::formatted("Too many arguments to {}. max: {}", part.function().name, function_metadata.parameters.size())),
-            });
-            return nullptr;
-        }
-
-        if (arguments.size() < function_metadata.parameters.size() && function_metadata.parameters[arguments.size()].required) {
-            ErrorReporter::the().report(InvalidValueError {
-                .value_type = "<transform-function>"_fly_string,
-                .value_string = part.function().original_source_text(),
-                .description = MUST(String::formatted("Required parameter at position {} is missing", arguments.size())),
-            });
-            return nullptr;
-        }
-
-        StyleValueVector values;
-        for (auto argument_index = 0u; argument_index < arguments.size(); ++argument_index) {
-            TokenStream argument_tokens { arguments[argument_index] };
-            argument_tokens.discard_whitespace();
-
-            switch (function_metadata.parameters[argument_index].type) {
-            case TransformFunctionParameterType::Angle: {
-                // These are `<angle> | <zero>` in the spec, so we have to check for both kinds.
-                if (auto angle_value = parse_angle_value(argument_tokens)) {
-                    values.append(angle_value.release_nonnull());
-                    break;
-                }
-                if (argument_tokens.next_token().is(Token::Type::Number) && argument_tokens.next_token().token().number_value() == 0) {
-                    argument_tokens.discard_a_token(); // 0
-                    values.append(AngleStyleValue::create(Angle::make_degrees(0)));
-                    break;
-                }
-                return nullptr;
-            }
-            case TransformFunctionParameterType::Length:
-            case TransformFunctionParameterType::LengthNone: {
-                if (auto length_value = parse_length_value(argument_tokens)) {
-                    values.append(length_value.release_nonnull());
-                    break;
-                }
-                if (function_metadata.parameters[argument_index].type == TransformFunctionParameterType::LengthNone
-                    && argument_tokens.next_token().is_ident("none"sv)) {
-
-                    argument_tokens.discard_a_token(); // none
-                    values.append(KeywordStyleValue::create(Keyword::None));
-                    break;
-                }
-                return nullptr;
-            }
-            case TransformFunctionParameterType::LengthPercentage: {
-                if (auto length_percentage_value = parse_length_percentage_value(argument_tokens)) {
-                    values.append(length_percentage_value.release_nonnull());
-                    break;
-                }
-                return nullptr;
-            }
-            case TransformFunctionParameterType::Number: {
-                if (auto number_value = parse_number_value(argument_tokens)) {
-                    values.append(number_value.release_nonnull());
-                    break;
-                }
-                return nullptr;
-            }
-            case TransformFunctionParameterType::NumberPercentage: {
-                if (auto number_percentage_value = parse_number_percentage_value(argument_tokens)) {
-                    values.append(number_percentage_value.release_nonnull());
-                    break;
-                }
-                return nullptr;
-            }
-            }
-
-            argument_tokens.discard_whitespace();
-            if (argument_tokens.has_next_token())
-                return nullptr;
-        }
-
-        transformations.append(TransformationStyleValue::create(PropertyID::Transform, function, move(values)));
-    }
-    transaction.commit();
-    return StyleValueList::create(move(transformations), StyleValueList::Separator::Space);
-}
-
 // https://www.w3.org/TR/css-transforms-1/#propdef-transform-origin
 RefPtr<StyleValue const> Parser::parse_transform_origin_value(TokenStream<ComponentValue>& tokens)
 {

Libraries/LibWeb/CSS/Parser/ValueParsing.cpp

@@ -67,6 +67,7 @@
 #include <LibWeb/CSS/StyleValues/StyleValueList.h>
 #include <LibWeb/CSS/StyleValues/SuperellipseStyleValue.h>
 #include <LibWeb/CSS/StyleValues/TimeStyleValue.h>
+#include <LibWeb/CSS/StyleValues/TransformationStyleValue.h>
 #include <LibWeb/CSS/StyleValues/URLStyleValue.h>
 #include <LibWeb/CSS/StyleValues/UnicodeRangeStyleValue.h>
 #include <LibWeb/CSS/StyleValues/UnresolvedStyleValue.h>
@@ -4700,6 +4701,131 @@ NonnullRefPtr<StyleValue const> Parser::resolve_unresolved_style_value(DOM::Abst
     return parsed_value.release_value();
 }
 
+// https://drafts.csswg.org/css-transforms-1/#typedef-transform-function
+RefPtr<StyleValue const> Parser::parse_transform_function_value(TokenStream<ComponentValue>& tokens)
+{
+    auto transaction = tokens.begin_transaction();
+    tokens.discard_whitespace();
+    auto const& part = tokens.consume_a_token();
+    if (!part.is_function())
+        return nullptr;
+    auto maybe_function = transform_function_from_string(part.function().name);
+    if (!maybe_function.has_value())
+        return nullptr;
+
+    auto context_guard = push_temporary_value_parsing_context(FunctionContext { part.function().name });
+
+    auto function = maybe_function.release_value();
+    auto function_metadata = transform_function_metadata(function);
+
+    auto function_tokens = TokenStream { part.function().value };
+    auto arguments = parse_a_comma_separated_list_of_component_values(function_tokens);
+
+    if (arguments.size() > function_metadata.parameters.size()) {
+        ErrorReporter::the().report(InvalidValueError {
+            .value_type = "<transform-function>"_fly_string,
+            .value_string = part.function().original_source_text(),
+            .description = MUST(String::formatted("Too many arguments to {}. max: {}", part.function().name, function_metadata.parameters.size())),
+        });
+        return nullptr;
+    }
+
+    if (arguments.size() < function_metadata.parameters.size() && function_metadata.parameters[arguments.size()].required) {
+        ErrorReporter::the().report(InvalidValueError {
+            .value_type = "<transform-function>"_fly_string,
+            .value_string = part.function().original_source_text(),
+            .description = MUST(String::formatted("Required parameter at position {} is missing", arguments.size())),
+        });
+        return nullptr;
+    }
+
+    StyleValueVector values;
+    for (auto argument_index = 0u; argument_index < arguments.size(); ++argument_index) {
+        TokenStream argument_tokens { arguments[argument_index] };
+        argument_tokens.discard_whitespace();
+
+        switch (function_metadata.parameters[argument_index].type) {
+        case TransformFunctionParameterType::Angle: {
+            // These are `<angle> | <zero>` in the spec, so we have to check for both kinds.
+            if (auto angle_value = parse_angle_value(argument_tokens)) {
+                values.append(angle_value.release_nonnull());
+                break;
+            }
+            if (argument_tokens.next_token().is(Token::Type::Number) && argument_tokens.next_token().token().number_value() == 0) {
+                argument_tokens.discard_a_token(); // 0
+                values.append(AngleStyleValue::create(Angle::make_degrees(0)));
+                break;
+            }
+            return nullptr;
+        }
+        case TransformFunctionParameterType::Length:
+        case TransformFunctionParameterType::LengthNone: {
+            if (auto length_value = parse_length_value(argument_tokens)) {
+                values.append(length_value.release_nonnull());
+                break;
+            }
+            if (function_metadata.parameters[argument_index].type == TransformFunctionParameterType::LengthNone
+                && argument_tokens.next_token().is_ident("none"sv)) {
+
+                argument_tokens.discard_a_token(); // none
+                values.append(KeywordStyleValue::create(Keyword::None));
+                break;
+            }
+            return nullptr;
+        }
+        case TransformFunctionParameterType::LengthPercentage: {
+            if (auto length_percentage_value = parse_length_percentage_value(argument_tokens)) {
+                values.append(length_percentage_value.release_nonnull());
+                break;
+            }
+            return nullptr;
+        }
+        case TransformFunctionParameterType::Number: {
+            if (auto number_value = parse_number_value(argument_tokens)) {
+                values.append(number_value.release_nonnull());
+                break;
+            }
+            return nullptr;
+        }
+        case TransformFunctionParameterType::NumberPercentage: {
+            if (auto number_percentage_value = parse_number_percentage_value(argument_tokens)) {
+                values.append(number_percentage_value.release_nonnull());
+                break;
+            }
+            return nullptr;
+        }
+        }
+
+        argument_tokens.discard_whitespace();
+        if (argument_tokens.has_next_token())
+            return nullptr;
+    }
+
+    transaction.commit();
+    return TransformationStyleValue::create(PropertyID::Transform, function, move(values));
+}
+
+// https://drafts.csswg.org/css-transforms-1/#typedef-transform-list
+RefPtr<StyleValue const> Parser::parse_transform_list_value(TokenStream<ComponentValue>& tokens)
+{
+    // <transform-list> = <transform-function>+
+    // https://www.w3.org/TR/css-transforms-1/#transform-property
+    StyleValueVector transformations;
+    auto transaction = tokens.begin_transaction();
+    while (tokens.has_next_token()) {
+        if (auto maybe_function = parse_transform_function_value(tokens)) {
+            transformations.append(maybe_function.release_nonnull());
+            tokens.discard_whitespace();
+            continue;
+        }
+        break;
+    }
+    if (transformations.is_empty())
+        return {};
+    transaction.commit();
+    return StyleValueList::create(move(transformations), StyleValueList::Separator::Space);
+}
+
 RefPtr<StyleValue const> Parser::parse_value(ValueType value_type, TokenStream<ComponentValue>& tokens)
 {
     switch (value_type) {
@@ -4758,6 +4884,10 @@ RefPtr<StyleValue const> Parser::parse_value(ValueType value_type, TokenStream<C
         return parse_string_value(tokens);
     case ValueType::Time:
         return parse_time_value(tokens);
+    case ValueType::TransformFunction:
+        return parse_transform_function_value(tokens);
+    case ValueType::TransformList:
+        return parse_transform_list_value(tokens);
     case ValueType::Url:
         return parse_url_value(tokens);
     }

Libraries/LibWeb/CSS/Properties.json

@@ -3783,7 +3783,13 @@
     "affects-layout": false,
     "affects-stacking-context": true,
     "percentages-resolve-to": "length",
-    "multiplicity": "list"
+    "multiplicity": "list",
+    "valid-types": [
+      "transform-list"
+    ],
+    "valid-identifiers": [
+      "none"
+    ]
   },
   "transform-box": {
     "animation-type": "discrete",

Libraries/LibWeb/CSS/PropertyNameAndID.h

@@ -7,7 +7,6 @@
 #pragma once
 
 #include <AK/FlyString.h>
-#include <AK/GenericShorthands.h>
 #include <AK/Optional.h>
 #include <LibWeb/CSS/PropertyID.h>
 #include <LibWeb/CSS/PropertyName.h>

Libraries/LibWeb/CSS/StylePropertyMap.cpp

@@ -62,7 +62,7 @@ static WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_r
     // To create an internal representation, given a string property and a string or CSSStyleValue value:
     return value.visit(
         [&property](GC::Root<CSSStyleValue> const& css_style_value) {
-            return css_style_value->create_an_internal_representation(property);
+            return css_style_value->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::Yes);
         },
         [&](String const& css_text) -> WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> {
             // If value is a USVString,
@@ -71,7 +71,7 @@ static WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> create_an_internal_r
             // FIXME: Avoid passing name as a string, as it gets immediately converted back to PropertyNameAndID.
             auto result = TRY(CSSStyleValue::parse_a_css_style_value(vm, property.name(), css_text, CSSStyleValue::ParseMultiple::No));
             // AD-HOC: Result is a CSSStyleValue but we want an internal representation, so... convert it again I guess?
-            return result.get<GC::Ref<CSSStyleValue>>()->create_an_internal_representation(property);
+            return result.get<GC::Ref<CSSStyleValue>>()->create_an_internal_representation(property, CSSStyleValue::PerformTypeCheck::Yes);
         });
 }
 

Libraries/LibWeb/CSS/ValueType.cpp

@@ -61,6 +61,10 @@ Optional<ValueType> value_type_from_string(StringView string)
         return ValueType::String;
     if (string.equals_ignoring_ascii_case("time"sv))
         return ValueType::Time;
+    if (string.equals_ignoring_ascii_case("transform-function"sv))
+        return ValueType::TransformFunction;
+    if (string.equals_ignoring_ascii_case("transform-list"sv))
+        return ValueType::TransformList;
     if (string.equals_ignoring_ascii_case("url"sv))
         return ValueType::Url;
     return {};
@@ -123,6 +127,10 @@ StringView value_type_to_string(ValueType value_type)
         return "String"sv;
     case Web::CSS::ValueType::Time:
         return "Time"sv;
+    case Web::CSS::ValueType::TransformFunction:
+        return "TransformFunction"sv;
+    case Web::CSS::ValueType::TransformList:
+        return "TransformList"sv;
     case Web::CSS::ValueType::Url:
         return "Url"sv;
     }

Libraries/LibWeb/CSS/ValueType.h

@@ -40,6 +40,8 @@ enum class ValueType : u8 {
     Resolution,
     String,
     Time,
+    TransformFunction,
+    TransformList,
     Url,
 };
 

Libraries/LibWeb/DOM/Document.cpp

@@ -3329,11 +3329,6 @@ StringView Document::visibility_state() const
     VERIFY_NOT_REACHED();
 }
 
-void Document::set_visibility_state(Badge<HTML::BrowsingContext>, HTML::VisibilityState visibility_state)
-{
-    m_visibility_state = visibility_state;
-}
-
 // https://html.spec.whatwg.org/multipage/interaction.html#update-the-visibility-state
 void Document::update_the_visibility_state(HTML::VisibilityState visibility_state)
 {

Libraries/LibWeb/DOM/Document.h

@@ -542,9 +542,6 @@ public:
     // https://html.spec.whatwg.org/multipage/interaction.html#update-the-visibility-state
     void update_the_visibility_state(HTML::VisibilityState);
 
-    // NOTE: This does not fire any events, unlike update_the_visibility_state().
-    void set_visibility_state(Badge<HTML::BrowsingContext>, HTML::VisibilityState);
-
     void run_the_resize_steps();
     void run_the_scroll_steps();
 

Libraries/LibWeb/DOM/Element.cpp

@@ -1245,7 +1245,7 @@ Vector<CSSPixelRect> Element::get_client_rects() const
     Vector<CSSPixelRect> rects;
     if (auto const* paintable_box = this->paintable_box()) {
         transform = Gfx::extract_2d_affine_transform(paintable_box->transform());
-        for (auto const* containing_block = paintable->containing_block(); !containing_block->is_viewport(); containing_block = containing_block->containing_block()) {
+        for (auto const* containing_block = paintable->containing_block(); !containing_block->is_viewport_paintable(); containing_block = containing_block->containing_block()) {
             transform = Gfx::extract_2d_affine_transform(containing_block->transform()).multiply(transform);
         }
 

Libraries/LibWeb/HTML/HTMLElement.cpp

@@ -788,6 +788,9 @@ void HTMLElement::set_subtree_inertness(bool is_inert)
         html_element.set_inert(is_inert);
         return TraversalDecision::Continue;
     });
+
+    if (auto paintable_box = this->paintable_box())
+        paintable_box->set_needs_paint_only_properties_update(true);
 }
 
 WebIDL::ExceptionOr<void> HTMLElement::cloned(Web::DOM::Node& copy, bool clone_children) const

Libraries/LibWeb/HTML/ImageBitmap.h

@@ -8,6 +8,7 @@
 
 #include <AK/OwnPtr.h>
 #include <LibGfx/Bitmap.h>
+#include <LibWeb/Bindings/ImageBitmapPrototype.h>
 #include <LibWeb/Bindings/PlatformObject.h>
 #include <LibWeb/Bindings/Serializable.h>
 #include <LibWeb/Bindings/Transferable.h>
@@ -23,6 +24,7 @@ struct ImageBitmapOptions {
     // FIXME: Implement the rest of the fields
     Optional<WebIDL::UnsignedLong> resize_width;
     Optional<WebIDL::UnsignedLong> resize_height;
+    Bindings::ResizeQuality resize_quality = Bindings::ResizeQuality::Low;
 };
 
 class ImageBitmap final : public Bindings::PlatformObject

Libraries/LibWeb/HTML/ImageBitmap.idl

@@ -28,5 +28,5 @@ dictionary ImageBitmapOptions {
     // FIXME: ColorSpaceConversion colorSpaceConversion = "default";
     [EnforceRange] unsigned long resizeWidth;
     [EnforceRange] unsigned long resizeHeight;
-    // FIXME: ResizeQuality resizeQuality = "low";
+    ResizeQuality resizeQuality = "low";
 };

Libraries/LibWeb/HTML/WindowOrWorkerGlobalScope.cpp

@@ -12,8 +12,10 @@
 #include <AK/Utf8View.h>
 #include <AK/Vector.h>
 #include <LibGC/Function.h>
+#include <LibGfx/ScalingMode.h>
 #include <LibJS/Runtime/Array.h>
 #include <LibJS/Runtime/TypedArray.h>
+#include <LibWeb/Bindings/ImageBitmapPrototype.h>
 #include <LibWeb/Bindings/MainThreadVM.h>
 #include <LibWeb/ContentSecurityPolicy/BlockingAlgorithms.h>
 #include <LibWeb/Crypto/Crypto.h>
@@ -198,10 +200,49 @@ static ErrorOr<NonnullRefPtr<Gfx::Bitmap>> crop_to_the_source_rectangle_with_for
     // 6. Let output be the rectangle on the plane denoted by sourceRectangle.
     auto output = TRY(input->cropped(source_rectangle, Gfx::Color::Transparent));
 
-    // FIXME: 7. Scale output to the size specified by outputWidth and outputHeight. The user agent should use the
+    // 7. Scale output to the size specified by outputWidth and outputHeight. The user agent should use the
     //  value of the resizeQuality option to guide the choice of scaling algorithm.
-    (void)output_width;
-    (void)output_height;
+    struct ScalingPass {
+        Gfx::ScalingMode mode { Gfx::ScalingMode::None };
+        int width { 0 };
+        int height { 0 };
+    };
+    Vector<ScalingPass> scaling_passes;
+    switch (options.has_value() ? options->resize_quality : Bindings::ResizeQuality::Low) {
+        // NOTE: The spec mentions Bicubic or Lanczos scaling as higher quality options; however, Skia does not implement the latter, so for now we will use SkCubicResampler::Mitchell() for both medium and high
+    case Bindings::ResizeQuality::High:
+        // The "high" value indicates a preference for a high level of image interpolation quality. High-quality image interpolation may be more computationally expensive than lower settings.
+    case Bindings::ResizeQuality::Medium:
+        // The "medium" value indicates a preference for a medium level of image interpolation quality.
+        scaling_passes.append(ScalingPass { .mode = Gfx::ScalingMode::BoxSampling, .width = output_width, .height = output_height });
+        break;
+    case Bindings::ResizeQuality::Low:
+        // The "low" value indicates a preference for a low level of image interpolation quality. Low-quality image interpolation may be more computationally efficient than higher settings.
+        scaling_passes.append(ScalingPass { .mode = Gfx::ScalingMode::BilinearBlend, .width = output_width, .height = output_height });
+        break;
+    case Bindings::ResizeQuality::Pixelated: {
+        // The "pixelated" value indicates a preference for scaling the image to preserve the pixelation of the original as much as possible, with minor smoothing as necessary to avoid distorting the image when the target size is not a clean multiple of the original.
+
+        // To implement "pixelated", for each axis independently, first determine the integer multiple of its natural size that puts it closest to the target size and is greater than zero. Scale it to this integer-multiple-size using nearest neighbor,
+        auto determine_closest_multiple = [](int const source_length, int const output_length) {
+            // NOTE: The previous cropping action would've failed if the source bitmap we are scaling had invalid lengths. Given the precondition that are lengths are always > 0, this integer division is safe from divide-by-zero and the quotient truncation is also safe as we will always round down
+            ASSERT(source_length > 0);
+            return output_length / source_length;
+        };
+        auto const source_width = source_rectangle.width();
+        auto const source_height = source_rectangle.height();
+        auto const width_multiple = determine_closest_multiple(source_width, output_width);
+        auto const height_multiple = determine_closest_multiple(source_height, output_height);
+        if (width_multiple > 0 && height_multiple > 0)
+            scaling_passes.append(ScalingPass { .mode = Gfx::ScalingMode::NearestNeighbor, .width = source_width * width_multiple, .height = source_height * height_multiple });
+
+        // then scale it the rest of the way to the target size using bilinear interpolation.
+        scaling_passes.append(ScalingPass { .mode = Gfx::ScalingMode::BilinearBlend, .width = output_width, .height = output_height });
+    } break;
+    }
+    for (ScalingPass& scaling_pass : scaling_passes) {
+        output = TRY(output->scaled(scaling_pass.width, scaling_pass.height, scaling_pass.mode));
+    }
 
     // FIXME: 8. If the value of the imageOrientation member of options is "flipY", output must be flipped vertically,
     //  disregarding any image orientation metadata of the source (such as EXIF metadata), if any. [EXIF]

Libraries/LibWeb/IndexedDB/Internal/Algorithms.cpp

@@ -1293,20 +1293,21 @@ void possibly_update_the_key_generator(GC::Ref<ObjectStore> store, GC::Ref<Key>
         return;
 
     // 2. Let value be the value of key.
-    auto temp_value = key->value_as_double();
+    auto value = key->value_as_double();
 
     // 3. Set value to the minimum of value and 2^53 (9007199254740992).
-    temp_value = min(temp_value, MAX_KEY_GENERATOR_VALUE);
+    value = min(value, MAX_KEY_GENERATOR_VALUE);
 
     // 4. Set value to the largest integer not greater than value.
-    u64 value = floor(temp_value);
+    value = floor(value);
 
     // 5. Let generator be store’s key generator.
     auto& generator = store->key_generator();
 
     // 6. If value is greater than or equal to generator’s current number, then set generator’s current number to value + 1.
-    if (value >= generator.current_number())
-        generator.set(value + 1);
+    if (value >= static_cast<double>(generator.current_number())) {
+        generator.set(static_cast<u64>(value + 1));
+    }
 }
 
 // https://w3c.github.io/IndexedDB/#inject-a-key-into-a-value-using-a-key-path

Libraries/LibWeb/Layout/BlockFormattingContext.cpp

@@ -809,14 +809,18 @@ void BlockFormattingContext::layout_block_level_box(Box const& box, BlockContain
     // This monster basically means: "a ListItemBox that does not have specified content in the ::marker pseudo-element".
     // This happens for ::marker with content 'normal'.
     // FIXME: We currently so not support ListItemBox-es generated by pseudo-elements. We will need to, eventually.
-    ListItemBox const* li_box = as_if<ListItemBox>(box);
-    bool is_list_item_box_without_css_content = li_box && (!(box.dom_node() && box.dom_node()->is_element() && as_if<DOM::Element const>(box.dom_node())->computed_properties(CSS::PseudoElement::Marker)->property(CSS::PropertyID::Content).is_content()));
+    auto const* li_box = as_if<ListItemBox>(box);
+    auto is_list_item_box_without_css_content = li_box != nullptr;
+    if (auto const* dom_node = as_if<DOM::Element>(box.dom_node()); li_box && dom_node) {
+        if (auto const computed_properties = dom_node->computed_properties(CSS::PseudoElement::Marker))
+            is_list_item_box_without_css_content = !computed_properties->property(CSS::PropertyID::Content).is_content();
+    }
 
     // Before we insert the children of a list item we need to know the location of the marker.
     // If we do not do this then left-floating elements inside the list item will push the marker to the right,
     // in some cases even causing it to overlap with the non-floating content of the list.
     CSSPixels left_space_before_children_formatted;
-    if (is_list_item_box_without_css_content) {
+    if (is_list_item_box_without_css_content && li_box->marker()) {
         // We need to ensure that our height and width are final before we calculate our left offset.
         // Otherwise, the y at which we calculate the intrusion by floats might be incorrect.
         ensure_sizes_correct_for_left_offset_calculation(*li_box);

Libraries/LibWeb/Layout/FormattingContext.cpp

@@ -1163,17 +1163,19 @@ void FormattingContext::compute_height_for_absolutely_positioned_non_replaced_el
     box_state.margin_bottom = margin_bottom.to_px_or_zero(box, width_of_containing_block);
 }
 
-CSSPixelRect FormattingContext::content_box_rect_in_static_position_ancestor_coordinate_space(Box const& box, Box const& ancestor_box) const
+CSSPixelRect FormattingContext::content_box_rect_in_static_position_ancestor_coordinate_space(Box const& box) const
 {
     auto box_used_values = m_state.get(box);
     CSSPixelRect rect = { { 0, 0 }, box_used_values.content_size() };
-    for (auto const* current = &box; current; current = current->static_position_containing_block()) {
-        if (current == &ancestor_box)
+    VERIFY(box_used_values.offset.is_zero()); // Set as result of this calculation
+    for (auto const* current = box.static_position_containing_block(); current; current = current->containing_block()) {
+        if (current == box.containing_block())
             return rect;
         auto const& current_state = m_state.get(*current);
         rect.translate_by(current_state.offset);
     }
-    // If we get here, ancestor_box was not an ancestor of `box`!
+    // If we get here, `ancestor_box` was not in the containing block chain of the static position containing block of `box`!
+    // Something about the containing block chain is set up incorrectly then.
     VERIFY_NOT_REACHED();
 }
 
@@ -1245,7 +1247,7 @@ void FormattingContext::layout_absolutely_positioned_element(Box const& box, Ava
     CSSPixelPoint used_offset;
 
     auto static_position = m_state.get(box).static_position();
-    auto offset_to_static_parent = content_box_rect_in_static_position_ancestor_coordinate_space(box, *box.containing_block());
+    auto offset_to_static_parent = content_box_rect_in_static_position_ancestor_coordinate_space(box);
     static_position += offset_to_static_parent.location();
 
     if (box.computed_values().inset().top().is_auto() && box.computed_values().inset().bottom().is_auto()) {

Libraries/LibWeb/Layout/FormattingContext.h

@@ -87,7 +87,7 @@ public:
     [[nodiscard]] CSSPixelRect content_box_rect(LayoutState::UsedValues const&) const;
     [[nodiscard]] CSSPixelRect content_box_rect_in_ancestor_coordinate_space(LayoutState::UsedValues const&, Box const& ancestor_box) const;
     [[nodiscard]] CSSPixels box_baseline(Box const&) const;
-    [[nodiscard]] CSSPixelRect content_box_rect_in_static_position_ancestor_coordinate_space(Box const&, Box const& ancestor_box) const;
+    [[nodiscard]] CSSPixelRect content_box_rect_in_static_position_ancestor_coordinate_space(Box const&) const;
 
     [[nodiscard]] CSSPixels containing_block_width_for(NodeWithStyleAndBoxModelMetrics const&) const;
 

Libraries/LibWeb/Painting/BackgroundPainting.cpp

@@ -167,7 +167,7 @@ void paint_background(DisplayListRecordingContext& context, PaintableBox const&
             background_positioning_area.set_location(paintable_box.layout_node().root().navigable()->viewport_scroll_offset());
             break;
         case CSS::BackgroundAttachment::Local:
-            if (!paintable_box.is_viewport()) {
+            if (!paintable_box.is_viewport_paintable()) {
                 auto scroll_offset = paintable_box.scroll_offset();
                 background_positioning_area.translate_by(-scroll_offset.x(), -scroll_offset.y());
             }

Libraries/LibWeb/Painting/Paintable.cpp

@@ -52,6 +52,17 @@ String Paintable::debug_description() const
     return MUST(String::formatted("{}({})", class_name(), layout_node().debug_description()));
 }
 
+void Paintable::resolve_paint_properties()
+{
+    m_visible_for_hit_testing = true;
+    if (auto dom_node = this->dom_node(); dom_node && dom_node->is_inert()) {
+        // https://html.spec.whatwg.org/multipage/interaction.html#inert-subtrees
+        // When a node is inert:
+        // - Hit-testing must act as if the 'pointer-events' CSS property were set to 'none'.
+        m_visible_for_hit_testing = false;
+    }
+}
+
 bool Paintable::is_visible() const
 {
     auto const& computed_values = this->computed_values();
@@ -90,13 +101,7 @@ CSS::ImmutableComputedValues const& Paintable::computed_values() const
 
 bool Paintable::visible_for_hit_testing() const
 {
-    // https://html.spec.whatwg.org/multipage/interaction.html#inert-subtrees
-    // When a node is inert:
-    // - Hit-testing must act as if the 'pointer-events' CSS property were set to 'none'.
-    if (auto dom_node = this->dom_node(); dom_node && dom_node->is_inert())
-        return false;
-
-    return computed_values().pointer_events() != CSS::PointerEvents::None;
+    return m_visible_for_hit_testing && computed_values().pointer_events() != CSS::PointerEvents::None;
 }
 
 void Paintable::set_dom_node(GC::Ptr<DOM::Node> dom_node)

Libraries/LibWeb/Painting/Paintable.h

@@ -145,7 +145,7 @@ public:
     SelectionState selection_state() const { return m_selection_state; }
     void set_selection_state(SelectionState state) { m_selection_state = state; }
 
-    virtual void resolve_paint_properties() { }
+    virtual void resolve_paint_properties();
 
     [[nodiscard]] String debug_description() const;
 
@@ -177,6 +177,7 @@ private:
     bool m_absolutely_positioned : 1 { false };
     bool m_floating : 1 { false };
     bool m_inline : 1 { false };
+    bool m_visible_for_hit_testing : 1 { true };
     bool m_needs_paint_only_properties_update : 1 { true };
 };
 

Libraries/LibWeb/Painting/PaintableBox.cpp

@@ -95,7 +95,7 @@ PaintableWithLines::~PaintableWithLines()
 
 CSSPixelPoint PaintableBox::scroll_offset() const
 {
-    if (is_viewport()) {
+    if (is_viewport_paintable()) {
         auto navigable = document().navigable();
         VERIFY(navigable);
         return navigable->viewport_scroll_offset();
@@ -361,7 +361,7 @@ bool PaintableBox::could_be_scrolled_by_wheel_event(ScrollDirection direction) c
     auto scrollable_overflow_size = direction == ScrollDirection::Horizontal ? scrollable_overflow_rect->width() : scrollable_overflow_rect->height();
     auto scrollport_size = direction == ScrollDirection::Horizontal ? absolute_padding_box_rect().width() : absolute_padding_box_rect().height();
     auto overflow_value_allows_scrolling = overflow == CSS::Overflow::Auto || overflow == CSS::Overflow::Scroll;
-    if ((is_viewport() && overflow != CSS::Overflow::Hidden) || overflow_value_allows_scrolling)
+    if ((is_viewport_paintable() && overflow != CSS::Overflow::Hidden) || overflow_value_allows_scrolling)
         return scrollable_overflow_size > scrollport_size;
     return false;
 }
@@ -488,7 +488,7 @@ void PaintableBox::paint(DisplayListRecordingContext& context, PaintPhase phase)
         }
     }
 
-    if (phase == PaintPhase::Overlay && (g_paint_viewport_scrollbars || !is_viewport()) && computed_values().scrollbar_width() != CSS::ScrollbarWidth::None) {
+    if (phase == PaintPhase::Overlay && (g_paint_viewport_scrollbars || !is_viewport_paintable()) && computed_values().scrollbar_width() != CSS::ScrollbarWidth::None) {
         auto scrollbar_colors = computed_values().scrollbar_color();
         if (auto scrollbar_data = compute_scrollbar_data(ScrollDirection::Vertical); scrollbar_data.has_value()) {
             auto gutter_rect = context.rounded_device_rect(scrollbar_data->gutter_rect).to_type<int>();
@@ -1153,10 +1153,10 @@ void PaintableBox::scroll_to_mouse_position(CSSPixelPoint position)
     auto scroll_position_in_pixels = CSSPixels::nearest_value_for(scroll_position * (scrollable_overflow_size - padding_size));
 
     // Set the new scroll offset.
-    auto new_scroll_offset = is_viewport() ? document().navigable()->viewport_scroll_offset() : scroll_offset();
+    auto new_scroll_offset = is_viewport_paintable() ? document().navigable()->viewport_scroll_offset() : scroll_offset();
     new_scroll_offset.set_primary_offset_for_orientation(orientation, scroll_position_in_pixels);
 
-    if (is_viewport())
+    if (is_viewport_paintable())
         document().navigable()->perform_scroll_of_viewport(new_scroll_offset);
     else
         (void)set_scroll_offset(new_scroll_offset);
@@ -1213,7 +1213,7 @@ TraversalDecision PaintableBox::hit_test(CSSPixelPoint position, HitTestType typ
     if (hit_test_scrollbars(position, callback) == TraversalDecision::Break)
         return TraversalDecision::Break;
 
-    if (is_viewport()) {
+    if (is_viewport_paintable()) {
         auto& viewport_paintable = const_cast<ViewportPaintable&>(static_cast<ViewportPaintable const&>(*this));
         viewport_paintable.build_stacking_context_tree_if_needed();
         viewport_paintable.document().update_paint_and_hit_testing_properties_if_needed();
@@ -1279,7 +1279,7 @@ Optional<HitTestResult> PaintableBox::hit_test(CSSPixelPoint position, HitTestTy
 TraversalDecision PaintableBox::hit_test_children(CSSPixelPoint position, HitTestType type, Function<TraversalDecision(HitTestResult)> const& callback) const
 {
     for (auto const* child = last_child(); child; child = child->previous_sibling()) {
-        if (child->layout_node().is_positioned() && child->computed_values().z_index().value_or(0) == 0)
+        if (child->is_positioned() && child->computed_values().z_index().value_or(0) == 0)
             continue;
         if (child->has_stacking_context())
             continue;
@@ -1390,7 +1390,7 @@ TraversalDecision PaintableWithLines::hit_test(CSSPixelPoint position, HitTestTy
         }
     }
 
-    if (!stacking_context() && is_visible() && (!layout_node().is_anonymous() || layout_node().is_positioned())
+    if (!stacking_context() && is_visible() && (!layout_node().is_anonymous() || is_positioned())
         && absolute_border_box_rect().contains(offset_position_adjusted_by_scroll_offset)) {
         if (callback(HitTestResult { const_cast<PaintableWithLines&>(*this) }) == TraversalDecision::Break)
             return TraversalDecision::Break;

Libraries/LibWeb/Painting/PaintableBox.h

@@ -213,8 +213,6 @@ public:
 
     Optional<CSSPixelRect> get_clip_rect() const;
 
-    bool is_viewport() const { return layout_node_with_style_and_box_metrics().is_viewport(); }
-
     virtual bool wants_mouse_events() const override;
 
     CSSPixelRect transform_box_rect() const;

Libraries/LibWeb/Painting/SVGPathPaintable.cpp

@@ -24,11 +24,6 @@ SVGPathPaintable::SVGPathPaintable(Layout::SVGGraphicsBox const& layout_box)
 {
 }
 
-Layout::SVGGraphicsBox const& SVGPathPaintable::layout_box() const
-{
-    return static_cast<Layout::SVGGraphicsBox const&>(layout_node());
-}
-
 TraversalDecision SVGPathPaintable::hit_test(CSSPixelPoint position, HitTestType type, Function<TraversalDecision(HitTestResult)> const& callback) const
 {
     if (!computed_path().has_value())
@@ -55,8 +50,7 @@ void SVGPathPaintable::resolve_paint_properties()
 {
     Base::resolve_paint_properties();
 
-    auto& graphics_element = layout_box().dom_node();
-
+    auto& graphics_element = dom_node();
     m_stroke_thickness = graphics_element.stroke_width().value_or(1);
     m_stroke_dasharray = graphics_element.stroke_dasharray();
     m_stroke_dashoffset = graphics_element.stroke_dashoffset().value_or(0);
@@ -72,7 +66,7 @@ void SVGPathPaintable::paint(DisplayListRecordingContext& context, PaintPhase ph
     if (phase != PaintPhase::Foreground)
         return;
 
-    auto& graphics_element = layout_box().dom_node();
+    auto& graphics_element = dom_node();
 
     auto const* svg_node = layout_box().first_ancestor_of_type<Layout::SVGSVGBox>();
     auto svg_element_rect = svg_node->paintable_box()->absolute_rect();

Libraries/LibWeb/Painting/SVGPathPaintable.h

@@ -24,7 +24,7 @@ public:
 
     virtual void paint(DisplayListRecordingContext&, PaintPhase) const override;
 
-    Layout::SVGGraphicsBox const& layout_box() const;
+    SVG::SVGGraphicsElement const& dom_node() const { return as<SVG::SVGGraphicsElement>(*Paintable::dom_node()); }
 
     void set_computed_path(Gfx::Path path)
     {

Libraries/LibWeb/Painting/StackingContext.cpp

@@ -86,7 +86,7 @@ static PaintPhase to_paint_phase(StackingContext::StackingContextPaintPhase phas
 
 void StackingContext::paint_node_as_stacking_context(Paintable const& paintable, DisplayListRecordingContext& context)
 {
-    if (paintable.layout_node().is_svg_svg_box()) {
+    if (paintable.is_svg_svg_paintable()) {
         paint_svg(context, static_cast<PaintableBox const&>(paintable), PaintPhase::Foreground);
         return;
     }
@@ -121,7 +121,7 @@ void StackingContext::paint_descendants(DisplayListRecordingContext& context, Pa
         if (child.has_stacking_context())
             return IterationDecision::Continue;
 
-        if (child.layout_node().is_svg_svg_box()) {
+        if (child.is_svg_svg_paintable()) {
             paint_svg(context, static_cast<PaintableBox const&>(child), to_paint_phase(phase));
             return IterationDecision::Continue;
         }
@@ -198,15 +198,15 @@ void StackingContext::paint_descendants(DisplayListRecordingContext& context, Pa
 
 void StackingContext::paint_child(DisplayListRecordingContext& context, StackingContext const& child)
 {
-    VERIFY(!child.paintable_box().layout_node().is_svg_box());
+    VERIFY(!child.paintable_box().is_svg_paintable());
     const_cast<StackingContext&>(child).set_last_paint_generation_id(context.paint_generation_id());
     child.paint(context);
 }
 
 void StackingContext::paint_internal(DisplayListRecordingContext& context) const
 {
-    VERIFY(!paintable_box().layout_node().is_svg_box());
-    if (paintable_box().layout_node().is_svg_svg_box()) {
+    VERIFY(!paintable_box().is_svg_paintable());
+    if (paintable_box().is_svg_svg_paintable()) {
         auto const& svg_svg_paintable = static_cast<SVGSVGPaintable const&>(paintable_box());
         paint_node(svg_svg_paintable, context, PaintPhase::Background);
         paint_node(svg_svg_paintable, context, PaintPhase::Border);

Libraries/LibWeb/Painting/ViewportPaintable.cpp

@@ -139,7 +139,7 @@ void ViewportPaintable::assign_clip_frames()
                 paintable_box.set_own_clip_frame(clip_frame.value());
             }
         }
-        for (auto block = paintable.containing_block(); !block->is_viewport(); block = block->containing_block()) {
+        for (auto block = paintable.containing_block(); !block->is_viewport_paintable(); block = block->containing_block()) {
             if (auto clip_frame = clip_state.get(block); clip_frame.has_value()) {
                 if (paintable.is_paintable_box()) {
                     auto& paintable_box = static_cast<PaintableBox&>(paintable);

Libraries/LibWebView/Application.cpp

@@ -10,6 +10,7 @@
 #include <LibCore/StandardPaths.h>
 #include <LibCore/System.h>
 #include <LibCore/TimeZoneWatcher.h>
+#include <LibDatabase/Database.h>
 #include <LibDevTools/DevToolsServer.h>
 #include <LibFileSystem/FileSystem.h>
 #include <LibImageDecoderClient/Client.h>
@@ -17,7 +18,6 @@
 #include <LibWeb/Loader/UserAgent.h>
 #include <LibWebView/Application.h>
 #include <LibWebView/CookieJar.h>
-#include <LibWebView/Database.h>
 #include <LibWebView/HeadlessWebView.h>
 #include <LibWebView/HelperProcess.h>
 #include <LibWebView/Menu.h>
@@ -117,6 +117,7 @@ ErrorOr<void> Application::initialize(Main::Arguments const& arguments)
     bool disable_site_isolation = false;
     bool enable_idl_tracing = false;
     bool disable_http_cache = false;
+    bool enable_http_disk_cache = false;
     bool enable_autoplay = false;
     bool expose_internals_object = false;
     bool force_cpu_painting = false;
@@ -164,6 +165,7 @@ ErrorOr<void> Application::initialize(Main::Arguments const& arguments)
     args_parser.add_option(disable_site_isolation, "Disable site isolation", "disable-site-isolation");
     args_parser.add_option(enable_idl_tracing, "Enable IDL tracing", "enable-idl-tracing");
     args_parser.add_option(disable_http_cache, "Disable HTTP cache", "disable-http-cache");
+    args_parser.add_option(enable_http_disk_cache, "Enable HTTP disk cache", "enable-http-disk-cache");
     args_parser.add_option(enable_autoplay, "Enable multimedia autoplay", "enable-autoplay");
     args_parser.add_option(expose_internals_object, "Expose internals object", "expose-internals-object");
     args_parser.add_option(force_cpu_painting, "Force CPU painting", "force-cpu-painting");
@@ -228,7 +230,6 @@ ErrorOr<void> Application::initialize(Main::Arguments const& arguments)
         .urls = sanitize_urls(raw_urls, m_settings.new_tab_page_url()),
         .raw_urls = move(raw_urls),
         .headless_mode = headless_mode,
-        .certificates = move(certificates),
         .new_window = new_window ? NewWindow::Yes : NewWindow::No,
         .force_new_process = force_new_process ? ForceNewProcess::Yes : ForceNewProcess::No,
         .allow_popups = allow_popups ? AllowPopups::Yes : AllowPopups::No,
@@ -252,6 +253,11 @@ ErrorOr<void> Application::initialize(Main::Arguments const& arguments)
     if (webdriver_content_ipc_path.has_value())
         m_browser_options.webdriver_content_ipc_path = *webdriver_content_ipc_path;
 
+    m_request_server_options = {
+        .certificates = move(certificates),
+        .enable_http_disk_cache = enable_http_disk_cache ? EnableHTTPDiskCache::Yes : EnableHTTPDiskCache::No,
+    };
+
     m_web_content_options = {
         .command_line = MUST(String::join(' ', m_arguments.strings)),
         .executable_path = MUST(String::from_byte_string(MUST(Core::System::current_executable_path()))),
@@ -347,9 +353,12 @@ ErrorOr<void> Application::launch_services()
     };
 
     if (m_browser_options.disable_sql_database == DisableSQLDatabase::No) {
-        m_database = Database::create().release_value_but_fixme_should_propagate_errors();
-        m_cookie_jar = CookieJar::create(*m_database).release_value_but_fixme_should_propagate_errors();
-        m_storage_jar = StorageJar::create(*m_database).release_value_but_fixme_should_propagate_errors();
+        // FIXME: Move this to a generic "Ladybird data directory" helper.
+        auto database_path = ByteString::formatted("{}/Ladybird", Core::StandardPaths::user_data_directory());
+
+        m_database = TRY(Database::Database::create(database_path, "Ladybird"sv));
+        m_cookie_jar = TRY(CookieJar::create(*m_database));
+        m_storage_jar = TRY(StorageJar::create(*m_database));
     } else {
         m_cookie_jar = CookieJar::create();
         m_storage_jar = StorageJar::create();
@@ -815,7 +824,10 @@ void Application::initialize_actions()
     m_debug_menu->add_separator();
 
     m_debug_menu->add_action(Action::create("Collect Garbage"sv, ActionID::CollectGarbage, debug_request("collect-garbage"sv)));
-    m_debug_menu->add_action(Action::create("Clear Cache"sv, ActionID::ClearCache, debug_request("clear-cache"sv)));
+    m_debug_menu->add_action(Action::create("Clear Cache"sv, ActionID::ClearCache, [this, clear_memory_cache = debug_request("clear_cache")]() {
+        m_request_server_client->async_clear_cache();
+        clear_memory_cache();
+    }));
     m_debug_menu->add_action(Action::create("Clear All Cookies"sv, ActionID::ClearCookies, [this]() { m_cookie_jar->clear_all_cookies(); }));
     m_debug_menu->add_separator();
 

Libraries/LibWebView/Application.h

@@ -12,6 +12,7 @@
 #include <AK/Swift.h>
 #include <LibCore/EventLoop.h>
 #include <LibCore/Forward.h>
+#include <LibDatabase/Forward.h>
 #include <LibDevTools/DevToolsDelegate.h>
 #include <LibDevTools/Forward.h>
 #include <LibImageDecoderClient/Client.h>
@@ -47,6 +48,7 @@ public:
     static Settings& settings() { return the().m_settings; }
 
     static BrowserOptions const& browser_options() { return the().m_browser_options; }
+    static RequestServerOptions const& request_server_options() { return the().m_request_server_options; }
     static WebContentOptions& web_content_options() { return the().m_web_content_options; }
 
     static Requests::RequestClient& request_server_client() { return *the().m_request_server_client; }
@@ -173,6 +175,7 @@ private:
 
     Main::Arguments m_arguments;
     BrowserOptions m_browser_options;
+    RequestServerOptions m_request_server_options;
     WebContentOptions m_web_content_options;
 
     RefPtr<Requests::RequestClient> m_request_server_client;
@@ -181,7 +184,7 @@ private:
     RefPtr<WebContentClient> m_spare_web_content_process;
     bool m_has_queued_task_to_launch_spare_web_content_process { false };
 
-    RefPtr<Database> m_database;
+    RefPtr<Database::Database> m_database;
     OwnPtr<CookieJar> m_cookie_jar;
     OwnPtr<StorageJar> m_storage_jar;
 

Libraries/LibWebView/CMakeLists.txt

@@ -7,7 +7,6 @@ set(SOURCES
     BrowserProcess.cpp
     ConsoleOutput.cpp
     CookieJar.cpp
-    Database.cpp
     DOMNodeProperties.cpp
     HeadlessWebView.cpp
     HelperProcess.cpp
@@ -70,16 +69,13 @@ set(GENERATED_SOURCES
 )
 
 ladybird_lib(LibWebView webview EXPLICIT_SYMBOL_EXPORT)
-target_link_libraries(LibWebView PRIVATE LibCore LibDevTools LibFileSystem LibGfx LibImageDecoderClient LibIPC LibRequests LibJS LibWeb LibUnicode LibURL LibSyntax LibTextCodec)
+target_link_libraries(LibWebView PRIVATE LibCore LibDatabase LibDevTools LibFileSystem LibGfx LibImageDecoderClient LibIPC LibRequests LibJS LibWeb LibUnicode LibURL LibSyntax LibTextCodec)
 
 if (APPLE)
     target_link_libraries(LibWebView PRIVATE LibThreading)
 endif()
 
 # Third-party
-find_package(SQLite3 REQUIRED)
-target_link_libraries(LibWebView PRIVATE SQLite::SQLite3)
-
 if (HAS_FONTCONFIG)
     target_link_libraries(LibWebView PRIVATE Fontconfig::Fontconfig)
 endif()

Libraries/LibWebView/CookieJar.cpp

@@ -11,6 +11,7 @@
 #include <AK/StringBuilder.h>
 #include <AK/Time.h>
 #include <AK/Vector.h>
+#include <LibDatabase/Database.h>
 #include <LibURL/URL.h>
 #include <LibWeb/Cookie/ParsedCookie.h>
 #include <LibWebView/CookieJar.h>
@@ -20,7 +21,7 @@ namespace WebView {
 
 static constexpr auto DATABASE_SYNCHRONIZATION_TIMER = AK::Duration::from_seconds(30);
 
-ErrorOr<NonnullOwnPtr<CookieJar>> CookieJar::create(Database& database)
+ErrorOr<NonnullOwnPtr<CookieJar>> CookieJar::create(Database::Database& database)
 {
     Statements statements {};
 
@@ -665,7 +666,7 @@ void CookieJar::PersistedStorage::insert_cookie(Web::Cookie::Cookie const& cooki
         cookie.persistent);
 }
 
-static Web::Cookie::Cookie parse_cookie(Database& database, Database::StatementID statement_id)
+static Web::Cookie::Cookie parse_cookie(Database::Database& database, Database::StatementID statement_id)
 {
     int column = 0;
     auto convert_text = [&](auto& field) { field = database.result_column<String>(statement_id, column++); };

Libraries/LibWebView/CookieJar.h

@@ -13,10 +13,10 @@
 #include <AK/StringView.h>
 #include <AK/Traits.h>
 #include <LibCore/Timer.h>
+#include <LibDatabase/Forward.h>
 #include <LibURL/Forward.h>
 #include <LibWeb/Cookie/Cookie.h>
 #include <LibWeb/Forward.h>
-#include <LibWebView/Database.h>
 #include <LibWebView/Forward.h>
 
 namespace WebView {
@@ -76,13 +76,13 @@ class WEBVIEW_API CookieJar {
         void insert_cookie(Web::Cookie::Cookie const& cookie);
         TransientStorage::Cookies select_all_cookies();
 
-        Database& database;
+        Database::Database& database;
         Statements statements;
         RefPtr<Core::Timer> synchronization_timer {};
     };
 
 public:
-    static ErrorOr<NonnullOwnPtr<CookieJar>> create(Database&);
+    static ErrorOr<NonnullOwnPtr<CookieJar>> create(Database::Database&);
     static NonnullOwnPtr<CookieJar> create();
 
     ~CookieJar();

Libraries/LibWebView/Forward.h

@@ -16,7 +16,6 @@ class Action;
 class Application;
 class Autocomplete;
 class CookieJar;
-class Database;
 class Menu;
 class OutOfProcessWebView;
 class ProcessManager;

Libraries/LibWebView/HelperProcess.cpp

@@ -201,17 +201,23 @@ ErrorOr<NonnullRefPtr<Web::HTML::WebWorkerClient>> launch_web_worker_process(Web
 
 ErrorOr<NonnullRefPtr<Requests::RequestClient>> launch_request_server_process()
 {
+    auto const& request_server_options = Application::request_server_options();
+
     Vector<ByteString> arguments;
 
-    for (auto const& certificate : WebView::Application::browser_options().certificates)
+    for (auto const& certificate : request_server_options.certificates)
         arguments.append(ByteString::formatted("--certificate={}", certificate));
 
+    if (request_server_options.enable_http_disk_cache == EnableHTTPDiskCache::Yes)
+        arguments.append("--enable-http-disk-cache"sv);
+
     if (auto server = mach_server_name(); server.has_value()) {
         arguments.append("--mach-server-name"sv);
         arguments.append(server.value());
     }
 
     auto client = TRY(launch_server_process<Requests::RequestClient>("RequestServer"sv, move(arguments)));
+
     WebView::Application::settings().dns_settings().visit(
         [](WebView::SystemDNS) {},
         [&](WebView::DNSOverTLS const& dns_over_tls) {

Libraries/LibWebView/Options.h

@@ -74,7 +74,6 @@ struct BrowserOptions {
     Optional<HeadlessMode> headless_mode;
     int window_width { 800 };
     int window_height { 600 };
-    Vector<ByteString> certificates {};
     NewWindow new_window { NewWindow::No };
     ForceNewProcess force_new_process { ForceNewProcess::No };
     AllowPopups allow_popups { AllowPopups::No };
@@ -87,6 +86,16 @@ struct BrowserOptions {
     Optional<u16> devtools_port;
 };
 
+enum class EnableHTTPDiskCache {
+    No,
+    Yes,
+};
+
+struct RequestServerOptions {
+    Vector<ByteString> certificates;
+    EnableHTTPDiskCache enable_http_disk_cache { EnableHTTPDiskCache::No };
+};
+
 enum class IsLayoutTestMode {
     No,
     Yes,

Libraries/LibWebView/StorageJar.cpp

@@ -6,6 +6,7 @@
 
 #include <AK/NonnullOwnPtr.h>
 #include <AK/StdLibExtras.h>
+#include <LibDatabase/Database.h>
 #include <LibWebView/StorageJar.h>
 
 namespace WebView {
@@ -13,7 +14,7 @@ namespace WebView {
 // Quota size is specified in https://storage.spec.whatwg.org/#registered-storage-endpoints
 static constexpr size_t LOCAL_STORAGE_QUOTA = 5 * MiB;
 
-ErrorOr<NonnullOwnPtr<StorageJar>> StorageJar::create(Database& database)
+ErrorOr<NonnullOwnPtr<StorageJar>> StorageJar::create(Database::Database& database)
 {
     Statements statements {};
 

Libraries/LibWebView/StorageJar.h

@@ -9,8 +9,8 @@
 #include <AK/HashMap.h>
 #include <AK/String.h>
 #include <AK/Traits.h>
+#include <LibDatabase/Forward.h>
 #include <LibWeb/StorageAPI/StorageEndpoint.h>
-#include <LibWebView/Database.h>
 #include <LibWebView/Forward.h>
 #include <LibWebView/StorageOperationError.h>
 
@@ -31,7 +31,7 @@ class WEBVIEW_API StorageJar {
     AK_MAKE_NONMOVABLE(StorageJar);
 
 public:
-    static ErrorOr<NonnullOwnPtr<StorageJar>> create(Database&);
+    static ErrorOr<NonnullOwnPtr<StorageJar>> create(Database::Database&);
     static NonnullOwnPtr<StorageJar> create();
 
     ~StorageJar();
@@ -71,7 +71,7 @@ private:
         void clear(StorageEndpointType storage_endpoint, String const& storage_key);
         Vector<String> get_keys(StorageEndpointType storage_endpoint, String const& storage_key);
 
-        Database& database;
+        Database::Database& database;
         Statements statements;
     };
 

Meta/import-wpt-test.py

@@ -157,6 +157,10 @@ def map_to_path(
         if source.resource.startswith("/") or not is_resource:
             file_path = Path(base_directory, source.resource.lstrip("/"))
         else:
+            parsed_url = urlparse(source.resource)
+            if parsed_url.scheme != "":
+                print(f"Skipping '{source.resource}'. Downloading external resources is not supported.")
+                continue
             # Add it as a sibling path if it's a relative resource
             sibling_location = Path(resource_path).parent
             parent_directory = Path(base_directory, sibling_location)

Services/RequestServer/CMakeLists.txt

@@ -3,6 +3,10 @@ set(CMAKE_AUTORCC OFF)
 set(CMAKE_AUTOUIC OFF)
 
 set(SOURCES
+    Cache/CacheEntry.cpp
+    Cache/CacheIndex.cpp
+    Cache/DiskCache.cpp
+    Cache/Utilities.cpp
     ConnectionFromClient.cpp
     WebSocketImplCurl.cpp
 )
@@ -33,7 +37,7 @@ target_include_directories(requestserverservice PRIVATE ${CMAKE_CURRENT_BINARY_D
 target_include_directories(requestserverservice PRIVATE ${LADYBIRD_SOURCE_DIR}/Services/)
 
 target_link_libraries(RequestServer PRIVATE requestserverservice)
-target_link_libraries(requestserverservice PUBLIC LibCore LibDNS LibMain LibCrypto LibFileSystem LibIPC LibMain LibTLS LibWebSocket LibURL LibTextCodec LibThreading CURL::libcurl)
+target_link_libraries(requestserverservice PUBLIC LibCore LibDatabase LibDNS LibCrypto LibFileSystem LibIPC LibMain LibTLS LibWebSocket LibURL LibTextCodec LibThreading CURL::libcurl)
 target_link_libraries(requestserverservice PRIVATE OpenSSL::Crypto OpenSSL::SSL)
 
 if (${CMAKE_SYSTEM_NAME} MATCHES "SunOS")

Services/RequestServer/Cache/CacheEntry.cpp

@@ -0,0 +1,368 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/JsonArray.h>
+#include <AK/JsonArraySerializer.h>
+#include <AK/JsonObject.h>
+#include <AK/JsonObjectSerializer.h>
+#include <AK/JsonValue.h>
+#include <AK/ScopeGuard.h>
+#include <LibCore/Notifier.h>
+#include <LibCore/System.h>
+#include <LibFileSystem/FileSystem.h>
+#include <RequestServer/Cache/CacheEntry.h>
+#include <RequestServer/Cache/CacheIndex.h>
+#include <RequestServer/Cache/DiskCache.h>
+#include <RequestServer/Cache/Utilities.h>
+
+namespace RequestServer {
+
+static LexicalPath path_for_cache_key(LexicalPath const& cache_directory, u64 cache_key)
+{
+    return cache_directory.append(MUST(String::formatted("{:016x}", cache_key)));
+}
+
+ErrorOr<CacheHeader> CacheHeader::read_from_stream(Stream& stream)
+{
+    CacheHeader header;
+    header.magic = TRY(stream.read_value<u32>());
+    header.version = TRY(stream.read_value<u32>());
+    header.url_size = TRY(stream.read_value<u32>());
+    header.url_hash = TRY(stream.read_value<u32>());
+    header.status_code = TRY(stream.read_value<u32>());
+    header.reason_phrase_size = TRY(stream.read_value<u32>());
+    header.reason_phrase_hash = TRY(stream.read_value<u32>());
+    header.headers_size = TRY(stream.read_value<u32>());
+    header.headers_hash = TRY(stream.read_value<u32>());
+    return header;
+}
+
+ErrorOr<void> CacheHeader::write_to_stream(Stream& stream) const
+{
+    TRY(stream.write_value(magic));
+    TRY(stream.write_value(version));
+    TRY(stream.write_value(url_size));
+    TRY(stream.write_value(url_hash));
+    TRY(stream.write_value(status_code));
+    TRY(stream.write_value(reason_phrase_size));
+    TRY(stream.write_value(reason_phrase_hash));
+    TRY(stream.write_value(headers_size));
+    TRY(stream.write_value(headers_hash));
+    return {};
+}
+
+ErrorOr<void> CacheFooter::write_to_stream(Stream& stream) const
+{
+    TRY(stream.write_value(data_size));
+    TRY(stream.write_value(crc32));
+    return {};
+}
+
+ErrorOr<CacheFooter> CacheFooter::read_from_stream(Stream& stream)
+{
+    CacheFooter footer;
+    footer.data_size = TRY(stream.read_value<u64>());
+    footer.crc32 = TRY(stream.read_value<u32>());
+    return footer;
+}
+
+CacheEntry::CacheEntry(DiskCache& disk_cache, CacheIndex& index, u64 cache_key, String url, LexicalPath path, CacheHeader cache_header)
+    : m_disk_cache(disk_cache)
+    , m_index(index)
+    , m_cache_key(cache_key)
+    , m_url(move(url))
+    , m_path(move(path))
+    , m_cache_header(cache_header)
+{
+}
+
+void CacheEntry::remove()
+{
+    (void)FileSystem::remove(m_path.string(), FileSystem::RecursionMode::Disallowed);
+    m_index.remove_entry(m_cache_key);
+}
+
+void CacheEntry::close_and_destory_cache_entry()
+{
+    m_disk_cache.cache_entry_closed({}, *this);
+}
+
+ErrorOr<NonnullOwnPtr<CacheEntryWriter>> CacheEntryWriter::create(DiskCache& disk_cache, CacheIndex& index, u64 cache_key, String url, u32 status_code, Optional<String> reason_phrase, HTTP::HeaderMap const& headers, UnixDateTime request_time)
+{
+    auto path = path_for_cache_key(disk_cache.cache_directory(), cache_key);
+
+    auto unbuffered_file = TRY(Core::File::open(path.string(), Core::File::OpenMode::Write));
+    auto file = TRY(Core::OutputBufferedFile::create(move(unbuffered_file)));
+
+    CacheHeader cache_header;
+
+    auto result = [&]() -> ErrorOr<void> {
+        StringBuilder builder;
+        auto headers_serializer = TRY(JsonArraySerializer<>::try_create(builder));
+
+        for (auto const& header : headers.headers()) {
+            if (is_header_exempted_from_storage(header.name))
+                continue;
+
+            auto header_serializer = TRY(headers_serializer.add_object());
+            TRY(header_serializer.add("name"sv, header.name));
+            TRY(header_serializer.add("value"sv, header.value));
+            TRY(header_serializer.finish());
+        }
+
+        TRY(headers_serializer.finish());
+
+        cache_header.url_size = url.byte_count();
+        cache_header.url_hash = url.hash();
+
+        cache_header.status_code = status_code;
+        cache_header.reason_phrase_size = reason_phrase.has_value() ? reason_phrase->byte_count() : 0;
+        cache_header.reason_phrase_hash = reason_phrase.has_value() ? reason_phrase->hash() : 0;
+
+        auto serialized_headers = builder.string_view();
+        cache_header.headers_size = serialized_headers.length();
+        cache_header.headers_hash = serialized_headers.hash();
+
+        TRY(file->write_value(cache_header));
+        TRY(file->write_until_depleted(url));
+        if (reason_phrase.has_value())
+            TRY(file->write_until_depleted(*reason_phrase));
+        TRY(file->write_until_depleted(serialized_headers));
+
+        return {};
+    }();
+
+    if (result.is_error()) {
+        (void)FileSystem::remove(path.string(), FileSystem::RecursionMode::Disallowed);
+        return result.release_error();
+    }
+
+    return adopt_own(*new CacheEntryWriter { disk_cache, index, cache_key, move(url), path, move(file), cache_header, request_time });
+}
+
+CacheEntryWriter::CacheEntryWriter(DiskCache& disk_cache, CacheIndex& index, u64 cache_key, String url, LexicalPath path, NonnullOwnPtr<Core::OutputBufferedFile> file, CacheHeader cache_header, UnixDateTime request_time)
+    : CacheEntry(disk_cache, index, cache_key, move(url), move(path), cache_header)
+    , m_file(move(file))
+    , m_request_time(request_time)
+    , m_response_time(UnixDateTime::now())
+{
+}
+
+ErrorOr<void> CacheEntryWriter::write_data(ReadonlyBytes data)
+{
+    if (m_marked_for_deletion) {
+        close_and_destory_cache_entry();
+        return Error::from_string_literal("Cache entry has been deleted");
+    }
+
+    if (auto result = m_file->write_until_depleted(data); result.is_error()) {
+        dbgln("\033[31;1mUnable to write to cache entry for{}\033[0m {}: {}", m_url, result.error());
+
+        remove();
+        close_and_destory_cache_entry();
+
+        return result.release_error();
+    }
+
+    m_cache_footer.data_size += data.size();
+
+    // FIXME: Update the crc.
+
+    dbgln("\033[36;1mSaved {} bytes for\033[0m {}", data.size(), m_url);
+    return {};
+}
+
+ErrorOr<void> CacheEntryWriter::flush()
+{
+    ScopeGuard guard { [&]() { close_and_destory_cache_entry(); } };
+
+    if (m_marked_for_deletion)
+        return Error::from_string_literal("Cache entry has been deleted");
+
+    if (auto result = m_file->write_value(m_cache_footer); result.is_error()) {
+        dbgln("\033[31;1mUnable to flush cache entry for{}\033[0m {}: {}", m_url, result.error());
+        remove();
+
+        return result.release_error();
+    }
+
+    m_index.create_entry(m_cache_key, m_url, m_cache_footer.data_size, m_request_time, m_response_time);
+
+    dbgln("\033[34;1mFinished caching\033[0m {} ({} bytes)", m_url, m_cache_footer.data_size);
+    return {};
+}
+
+ErrorOr<NonnullOwnPtr<CacheEntryReader>> CacheEntryReader::create(DiskCache& disk_cache, CacheIndex& index, u64 cache_key, u64 data_size)
+{
+    auto path = path_for_cache_key(disk_cache.cache_directory(), cache_key);
+
+    auto file = TRY(Core::File::open(path.string(), Core::File::OpenMode::Read));
+    auto fd = file->fd();
+
+    CacheHeader cache_header;
+
+    String url;
+    Optional<String> reason_phrase;
+    HTTP::HeaderMap headers;
+
+    auto result = [&]() -> ErrorOr<void> {
+        cache_header = TRY(file->read_value<CacheHeader>());
+
+        if (cache_header.magic != CacheHeader::CACHE_MAGIC)
+            return Error::from_string_literal("Magic value mismatch");
+        if (cache_header.version != CacheHeader::CACHE_VERSION)
+            return Error::from_string_literal("Version mismatch");
+
+        url = TRY(String::from_stream(*file, cache_header.url_size));
+        if (url.hash() != cache_header.url_hash)
+            return Error::from_string_literal("URL hash mismatch");
+
+        if (cache_header.reason_phrase_size != 0) {
+            reason_phrase = TRY(String::from_stream(*file, cache_header.reason_phrase_size));
+            if (reason_phrase->hash() != cache_header.reason_phrase_hash)
+                return Error::from_string_literal("Reason phrase hash mismatch");
+        }
+
+        auto serialized_headers = TRY(String::from_stream(*file, cache_header.headers_size));
+        if (serialized_headers.hash() != cache_header.headers_hash)
+            return Error::from_string_literal("HTTP headers hash mismatch");
+
+        auto json_headers = TRY(JsonValue::from_string(serialized_headers));
+        if (!json_headers.is_array())
+            return Error::from_string_literal("Expected HTTP headers to be a JSON array");
+
+        TRY(json_headers.as_array().try_for_each([&](JsonValue const& header) -> ErrorOr<void> {
+            if (!header.is_object())
+                return Error::from_string_literal("Expected headers entry to be a JSON object");
+
+            auto name = header.as_object().get_string("name"sv);
+            auto value = header.as_object().get_string("value"sv);
+
+            if (!name.has_value() || !value.has_value())
+                return Error::from_string_literal("Missing/invalid data in headers entry");
+
+            headers.set(name->to_byte_string(), value->to_byte_string());
+            return {};
+        }));
+
+        return {};
+    }();
+
+    if (result.is_error()) {
+        (void)FileSystem::remove(path.string(), FileSystem::RecursionMode::Disallowed);
+        return result.release_error();
+    }
+
+    auto data_offset = sizeof(CacheHeader) + cache_header.url_size + cache_header.reason_phrase_size + cache_header.headers_size;
+
+    return adopt_own(*new CacheEntryReader { disk_cache, index, cache_key, move(url), move(path), move(file), fd, cache_header, move(reason_phrase), move(headers), data_offset, data_size });
+}
+
+CacheEntryReader::CacheEntryReader(DiskCache& disk_cache, CacheIndex& index, u64 cache_key, String url, LexicalPath path, NonnullOwnPtr<Core::File> file, int fd, CacheHeader cache_header, Optional<String> reason_phrase, HTTP::HeaderMap header_map, u64 data_offset, u64 data_size)
+    : CacheEntry(disk_cache, index, cache_key, move(url), move(path), cache_header)
+    , m_file(move(file))
+    , m_fd(fd)
+    , m_reason_phrase(move(reason_phrase))
+    , m_headers(move(header_map))
+    , m_data_offset(data_offset)
+    , m_data_size(data_size)
+{
+}
+
+void CacheEntryReader::pipe_to(int pipe_fd, Function<void(u64)> on_complete, Function<void(u64)> on_error)
+{
+    VERIFY(m_pipe_fd == -1);
+    m_pipe_fd = pipe_fd;
+
+    m_on_pipe_complete = move(on_complete);
+    m_on_pipe_error = move(on_error);
+
+    if (m_marked_for_deletion) {
+        pipe_error(Error::from_string_literal("Cache entry has been deleted"));
+        return;
+    }
+
+    m_pipe_write_notifier = Core::Notifier::construct(m_pipe_fd, Core::NotificationType::Write);
+    m_pipe_write_notifier->set_enabled(false);
+
+    m_pipe_write_notifier->on_activation = [this]() {
+        m_pipe_write_notifier->set_enabled(false);
+        pipe_without_blocking();
+    };
+
+    pipe_without_blocking();
+}
+
+void CacheEntryReader::pipe_without_blocking()
+{
+    if (m_marked_for_deletion) {
+        pipe_error(Error::from_string_literal("Cache entry has been deleted"));
+        return;
+    }
+
+    auto result = Core::System::transfer_file_through_pipe(m_fd, m_pipe_fd, m_data_offset + m_bytes_piped, m_data_size - m_bytes_piped);
+
+    if (result.is_error()) {
+        if (result.error().code() != EAGAIN && result.error().code() != EWOULDBLOCK)
+            pipe_error(result.release_error());
+        else
+            m_pipe_write_notifier->set_enabled(true);
+
+        return;
+    }
+
+    m_bytes_piped += result.value();
+
+    if (m_bytes_piped == m_data_size) {
+        pipe_complete();
+        return;
+    }
+
+    pipe_without_blocking();
+}
+
+void CacheEntryReader::pipe_complete()
+{
+    if (auto result = read_and_validate_footer(); result.is_error()) {
+        dbgln("\033[31;1mError validating cache entry for\033[0m {}: {}", m_url, result.error());
+        remove();
+
+        if (m_on_pipe_error)
+            m_on_pipe_error(m_bytes_piped);
+    } else {
+        m_index.update_last_access_time(m_cache_key);
+
+        if (m_on_pipe_complete)
+            m_on_pipe_complete(m_bytes_piped);
+    }
+
+    close_and_destory_cache_entry();
+}
+
+void CacheEntryReader::pipe_error(Error error)
+{
+    dbgln("\033[31;1mError transferring cache to pipe for\033[0m {}: {}", m_url, error);
+
+    if (m_on_pipe_error)
+        m_on_pipe_error(m_bytes_piped);
+
+    close_and_destory_cache_entry();
+}
+
+ErrorOr<void> CacheEntryReader::read_and_validate_footer()
+{
+    TRY(m_file->seek(m_data_offset + m_data_size, SeekMode::SetPosition));
+    m_cache_footer = TRY(m_file->read_value<CacheFooter>());
+
+    if (m_cache_footer.data_size != m_data_size)
+        return Error::from_string_literal("Invalid data size in footer");
+
+    // FIXME: Validate the crc.
+
+    return {};
+}
+
+}

Services/RequestServer/Cache/CacheEntry.h

@@ -0,0 +1,135 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Error.h>
+#include <AK/LexicalPath.h>
+#include <AK/Optional.h>
+#include <AK/String.h>
+#include <AK/Types.h>
+#include <LibCore/File.h>
+#include <LibHTTP/HeaderMap.h>
+#include <RequestServer/Forward.h>
+
+namespace RequestServer {
+
+struct [[gnu::packed]] CacheHeader {
+    static ErrorOr<CacheHeader> read_from_stream(Stream&);
+    ErrorOr<void> write_to_stream(Stream&) const;
+
+    static constexpr auto CACHE_MAGIC = 0xcafef00du;
+    static constexpr auto CACHE_VERSION = 1;
+
+    u32 magic { CACHE_MAGIC };
+    u32 version { CACHE_VERSION };
+
+    u32 url_size { 0 };
+    u32 url_hash { 0 };
+
+    u32 status_code { 0 };
+    u32 reason_phrase_size { 0 };
+    u32 reason_phrase_hash { 0 };
+
+    u32 headers_size { 0 };
+    u32 headers_hash { 0 };
+};
+
+struct [[gnu::packed]] CacheFooter {
+    static ErrorOr<CacheFooter> read_from_stream(Stream&);
+    ErrorOr<void> write_to_stream(Stream&) const;
+
+    u64 data_size { 0 };
+    u32 crc32 { 0 };
+};
+
+// A cache entry is an amalgamation of all information needed to reconstruct HTTP responses. It is created once we have
+// received the response headers for a request. The body is streamed into the entry as it is received. The cache format
+// on disk is:
+//
+//     [CacheHeader][URL][ReasonPhrase][HttpHeaders][Data][CacheFooter]
+class CacheEntry {
+public:
+    virtual ~CacheEntry() = default;
+
+    void remove();
+
+    void mark_for_deletion(Badge<DiskCache>) { m_marked_for_deletion = true; }
+
+protected:
+    CacheEntry(DiskCache&, CacheIndex&, u64 cache_key, String url, LexicalPath, CacheHeader);
+
+    void close_and_destory_cache_entry();
+
+    DiskCache& m_disk_cache;
+    CacheIndex& m_index;
+
+    u64 m_cache_key { 0 };
+
+    String m_url;
+    LexicalPath m_path;
+
+    CacheHeader m_cache_header;
+    CacheFooter m_cache_footer;
+
+    bool m_marked_for_deletion { false };
+};
+
+class CacheEntryWriter : public CacheEntry {
+public:
+    static ErrorOr<NonnullOwnPtr<CacheEntryWriter>> create(DiskCache&, CacheIndex&, u64 cache_key, String url, u32 status_code, Optional<String> reason_phrase, HTTP::HeaderMap const&, UnixDateTime request_time);
+    virtual ~CacheEntryWriter() override = default;
+
+    ErrorOr<void> write_data(ReadonlyBytes);
+    ErrorOr<void> flush();
+
+private:
+    CacheEntryWriter(DiskCache&, CacheIndex&, u64 cache_key, String url, LexicalPath, NonnullOwnPtr<Core::OutputBufferedFile>, CacheHeader, UnixDateTime request_time);
+
+    NonnullOwnPtr<Core::OutputBufferedFile> m_file;
+
+    UnixDateTime m_request_time;
+    UnixDateTime m_response_time;
+};
+
+class CacheEntryReader : public CacheEntry {
+public:
+    static ErrorOr<NonnullOwnPtr<CacheEntryReader>> create(DiskCache&, CacheIndex&, u64 cache_key, u64 data_size);
+    virtual ~CacheEntryReader() override = default;
+
+    void pipe_to(int pipe_fd, Function<void(u64 bytes_piped)> on_complete, Function<void(u64 bytes_piped)> on_error);
+
+    u32 status_code() const { return m_cache_header.status_code; }
+    Optional<String> const& reason_phrase() const { return m_reason_phrase; }
+    HTTP::HeaderMap const& headers() const { return m_headers; }
+
+private:
+    CacheEntryReader(DiskCache&, CacheIndex&, u64 cache_key, String url, LexicalPath, NonnullOwnPtr<Core::File>, int fd, CacheHeader, Optional<String> reason_phrase, HTTP::HeaderMap, u64 data_offset, u64 data_size);
+
+    void pipe_without_blocking();
+    void pipe_complete();
+    void pipe_error(Error);
+
+    ErrorOr<void> read_and_validate_footer();
+
+    NonnullOwnPtr<Core::File> m_file;
+    int m_fd { -1 };
+
+    RefPtr<Core::Notifier> m_pipe_write_notifier;
+    int m_pipe_fd { -1 };
+
+    Function<void(u64)> m_on_pipe_complete;
+    Function<void(u64)> m_on_pipe_error;
+    u64 m_bytes_piped { 0 };
+
+    Optional<String> m_reason_phrase;
+    HTTP::HeaderMap m_headers;
+
+    u64 const m_data_offset { 0 };
+    u64 const m_data_size { 0 };
+};
+
+}

Services/RequestServer/Cache/CacheIndex.cpp

@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <RequestServer/Cache/CacheIndex.h>
+
+namespace RequestServer {
+
+ErrorOr<CacheIndex> CacheIndex::create(Database::Database& database)
+{
+    auto create_table = TRY(database.prepare_statement(R"#(
+        CREATE TABLE IF NOT EXISTS CacheIndex (
+            cache_key INTEGER,
+            url TEXT,
+            data_size INTEGER,
+            request_time INTEGER,
+            response_time INTEGER,
+            last_access_time INTEGER,
+            PRIMARY KEY(cache_key)
+        );)#"sv));
+    database.execute_statement(create_table, {});
+
+    Statements statements {};
+    statements.insert_entry = TRY(database.prepare_statement("INSERT OR REPLACE INTO CacheIndex VALUES (?, ?, ?, ?, ?, ?);"sv));
+    statements.remove_entry = TRY(database.prepare_statement("DELETE FROM CacheIndex WHERE cache_key = ?;"sv));
+    statements.remove_all_entries = TRY(database.prepare_statement("DELETE FROM CacheIndex;"sv));
+    statements.select_entry = TRY(database.prepare_statement("SELECT * FROM CacheIndex WHERE cache_key = ?;"sv));
+    statements.update_last_access_time = TRY(database.prepare_statement("UPDATE CacheIndex SET last_access_time = ? WHERE cache_key = ?;"sv));
+
+    return CacheIndex { database, statements };
+}
+
+CacheIndex::CacheIndex(Database::Database& database, Statements statements)
+    : m_database(database)
+    , m_statements(statements)
+{
+}
+
+void CacheIndex::create_entry(u64 cache_key, String url, u64 data_size, UnixDateTime request_time, UnixDateTime response_time)
+{
+    auto now = UnixDateTime::now();
+
+    Entry entry {
+        .cache_key = cache_key,
+        .url = move(url),
+        .data_size = data_size,
+        .request_time = request_time,
+        .response_time = response_time,
+        .last_access_time = now,
+    };
+
+    m_database.execute_statement(m_statements.insert_entry, {}, entry.cache_key, entry.url, entry.data_size, entry.request_time, entry.response_time, entry.last_access_time);
+    m_entries.set(cache_key, move(entry));
+}
+
+void CacheIndex::remove_entry(u64 cache_key)
+{
+    m_database.execute_statement(m_statements.remove_entry, {}, cache_key);
+    m_entries.remove(cache_key);
+}
+
+void CacheIndex::remove_all_entries()
+{
+    m_database.execute_statement(m_statements.remove_all_entries, {});
+    m_entries.clear();
+}
+
+void CacheIndex::update_last_access_time(u64 cache_key)
+{
+    auto entry = m_entries.get(cache_key);
+    if (!entry.has_value())
+        return;
+
+    auto now = UnixDateTime::now();
+
+    m_database.execute_statement(m_statements.update_last_access_time, {}, now, cache_key);
+    entry->last_access_time = now;
+}
+
+Optional<CacheIndex::Entry&> CacheIndex::find_entry(u64 cache_key)
+{
+    if (auto entry = m_entries.get(cache_key); entry.has_value())
+        return entry;
+
+    m_database.execute_statement(
+        m_statements.select_entry, [&](auto statement_id) {
+            int column = 0;
+
+            auto cache_key = m_database.result_column<u64>(statement_id, column++);
+            auto url = m_database.result_column<String>(statement_id, column++);
+            auto data_size = m_database.result_column<u64>(statement_id, column++);
+            auto request_time = m_database.result_column<UnixDateTime>(statement_id, column++);
+            auto response_time = m_database.result_column<UnixDateTime>(statement_id, column++);
+            auto last_access_time = m_database.result_column<UnixDateTime>(statement_id, column++);
+
+            Entry entry { cache_key, move(url), data_size, request_time, response_time, last_access_time };
+            m_entries.set(cache_key, move(entry));
+        },
+        cache_key);
+
+    return m_entries.get(cache_key);
+}
+
+}

Services/RequestServer/Cache/CacheIndex.h

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Error.h>
+#include <AK/HashMap.h>
+#include <AK/Time.h>
+#include <AK/Types.h>
+#include <LibDatabase/Database.h>
+
+namespace RequestServer {
+
+// The cache index is a SQL database containing metadata about each cache entry. An entry in the index is created once
+// the entire cache entry has been successfully written to disk.
+class CacheIndex {
+    struct Entry {
+        u64 cache_key { 0 };
+
+        String url;
+        u64 data_size { 0 };
+
+        UnixDateTime request_time;
+        UnixDateTime response_time;
+        UnixDateTime last_access_time;
+    };
+
+public:
+    static ErrorOr<CacheIndex> create(Database::Database&);
+
+    void create_entry(u64 cache_key, String url, u64 data_size, UnixDateTime request_time, UnixDateTime response_time);
+    void remove_entry(u64 cache_key);
+    void remove_all_entries();
+
+    Optional<Entry&> find_entry(u64 cache_key);
+
+    void update_last_access_time(u64 cache_key);
+
+private:
+    struct Statements {
+        Database::StatementID insert_entry { 0 };
+        Database::StatementID remove_entry { 0 };
+        Database::StatementID remove_all_entries { 0 };
+        Database::StatementID select_entry { 0 };
+        Database::StatementID update_last_access_time { 0 };
+    };
+
+    CacheIndex(Database::Database&, Statements);
+
+    Database::Database& m_database;
+    Statements m_statements;
+
+    HashMap<u32, Entry> m_entries;
+};
+
+}

Services/RequestServer/Cache/DiskCache.cpp

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibCore/DirIterator.h>
+#include <LibCore/StandardPaths.h>
+#include <LibFileSystem/FileSystem.h>
+#include <LibURL/URL.h>
+#include <RequestServer/Cache/DiskCache.h>
+#include <RequestServer/Cache/Utilities.h>
+
+namespace RequestServer {
+
+static constexpr auto INDEX_DATABASE = "INDEX"sv;
+
+ErrorOr<DiskCache> DiskCache::create()
+{
+    auto cache_directory = LexicalPath::join(Core::StandardPaths::cache_directory(), "Ladybird"sv, "Cache"sv);
+
+    auto database = TRY(Database::Database::create(cache_directory.string(), INDEX_DATABASE));
+    auto index = TRY(CacheIndex::create(database));
+
+    return DiskCache { move(database), move(cache_directory), move(index) };
+}
+
+DiskCache::DiskCache(NonnullRefPtr<Database::Database> database, LexicalPath cache_directory, CacheIndex index)
+    : m_database(move(database))
+    , m_cache_directory(move(cache_directory))
+    , m_index(move(index))
+{
+}
+
+Optional<CacheEntryWriter&> DiskCache::create_entry(URL::URL const& url, StringView method, u32 status_code, Optional<String> reason_phrase, HTTP::HeaderMap const& headers, UnixDateTime request_time)
+{
+    if (!is_cacheable(method, status_code, headers))
+        return {};
+
+    if (auto freshness = calculate_freshness_lifetime(headers); freshness.is_negative() || freshness.is_zero())
+        return {};
+
+    auto serialized_url = serialize_url_for_cache_storage(url);
+    auto cache_key = create_cache_key(serialized_url, method);
+
+    auto cache_entry = CacheEntryWriter::create(*this, m_index, cache_key, move(serialized_url), status_code, move(reason_phrase), headers, request_time);
+    if (cache_entry.is_error()) {
+        dbgln("\033[31;1mUnable to create cache entry for\033[0m {}: {}", url, cache_entry.error());
+        return {};
+    }
+
+    dbgln("\033[32;1mCreated disk cache entry for\033[0m {}", url);
+
+    auto address = reinterpret_cast<FlatPtr>(cache_entry.value().ptr());
+    m_open_cache_entries.set(address, cache_entry.release_value());
+
+    return static_cast<CacheEntryWriter&>(**m_open_cache_entries.get(address));
+}
+
+Optional<CacheEntryReader&> DiskCache::open_entry(URL::URL const& url, StringView method)
+{
+    auto serialized_url = serialize_url_for_cache_storage(url);
+    auto cache_key = create_cache_key(serialized_url, method);
+
+    auto index_entry = m_index.find_entry(cache_key);
+    if (!index_entry.has_value()) {
+        dbgln("\033[35;1mNo disk cache entry for\033[0m {}", url);
+        return {};
+    }
+
+    auto cache_entry = CacheEntryReader::create(*this, m_index, cache_key, index_entry->data_size);
+    if (cache_entry.is_error()) {
+        dbgln("\033[31;1mUnable to open cache entry for\033[0m {}: {}", url, cache_entry.error());
+        m_index.remove_entry(cache_key);
+        return {};
+    }
+
+    auto freshness_lifetime = calculate_freshness_lifetime(cache_entry.value()->headers());
+    auto current_age = calculate_age(cache_entry.value()->headers(), index_entry->request_time, index_entry->response_time);
+
+    if (!is_response_fresh(freshness_lifetime, current_age)) {
+        dbgln("\033[33;1mCache entry expired for\033[0m {} (lifetime={}s age={}s)", url, freshness_lifetime.to_seconds(), current_age.to_seconds());
+        cache_entry.value()->remove();
+        return {};
+    }
+
+    dbgln("\033[32;1mOpened disk cache entry for\033[0m {} (lifetime={}s age={}s) ({} bytes)", url, freshness_lifetime.to_seconds(), current_age.to_seconds(), index_entry->data_size);
+
+    auto address = reinterpret_cast<FlatPtr>(cache_entry.value().ptr());
+    m_open_cache_entries.set(address, cache_entry.release_value());
+
+    return static_cast<CacheEntryReader&>(**m_open_cache_entries.get(address));
+}
+
+void DiskCache::clear_cache()
+{
+    for (auto& [_, cache_entry] : m_open_cache_entries)
+        cache_entry->mark_for_deletion({});
+
+    m_index.remove_all_entries();
+
+    Core::DirIterator it { m_cache_directory.string(), Core::DirIterator::SkipDots };
+    size_t cache_entries { 0 };
+
+    while (it.has_next()) {
+        auto entry = it.next_full_path();
+        if (LexicalPath { entry }.title() == INDEX_DATABASE)
+            continue;
+
+        (void)FileSystem::remove(entry, FileSystem::RecursionMode::Disallowed);
+        ++cache_entries;
+    }
+
+    dbgln("Cleared {} disk cache entries", cache_entries);
+}
+
+void DiskCache::cache_entry_closed(Badge<CacheEntry>, CacheEntry const& cache_entry)
+{
+    auto address = reinterpret_cast<FlatPtr>(&cache_entry);
+    m_open_cache_entries.remove(address);
+}
+
+}

Services/RequestServer/Cache/DiskCache.h

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Error.h>
+#include <AK/LexicalPath.h>
+#include <AK/Optional.h>
+#include <AK/StringView.h>
+#include <AK/Time.h>
+#include <AK/Types.h>
+#include <LibDatabase/Database.h>
+#include <LibHTTP/HeaderMap.h>
+#include <LibURL/Forward.h>
+#include <RequestServer/Cache/CacheEntry.h>
+#include <RequestServer/Cache/CacheIndex.h>
+
+namespace RequestServer {
+
+class DiskCache {
+public:
+    static ErrorOr<DiskCache> create();
+
+    Optional<CacheEntryWriter&> create_entry(URL::URL const&, StringView method, u32 status_code, Optional<String> reason_phrase, HTTP::HeaderMap const&, UnixDateTime request_time);
+    Optional<CacheEntryReader&> open_entry(URL::URL const&, StringView method);
+    void clear_cache();
+
+    LexicalPath const& cache_directory() { return m_cache_directory; }
+
+    void cache_entry_closed(Badge<CacheEntry>, CacheEntry const&);
+
+private:
+    DiskCache(NonnullRefPtr<Database::Database>, LexicalPath cache_directory, CacheIndex);
+
+    NonnullRefPtr<Database::Database> m_database;
+
+    HashMap<FlatPtr, NonnullOwnPtr<CacheEntry>> m_open_cache_entries;
+
+    LexicalPath m_cache_directory;
+    CacheIndex m_index;
+};
+
+}

Services/RequestServer/Cache/Utilities.cpp

@@ -0,0 +1,220 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibCrypto/Hash/SHA1.h>
+#include <LibURL/URL.h>
+#include <RequestServer/Cache/Utilities.h>
+
+namespace RequestServer {
+
+static Optional<StringView> extract_cache_control_directive(StringView cache_control, StringView directive)
+{
+    Optional<StringView> result;
+
+    cache_control.for_each_split_view(","sv, SplitBehavior::Nothing, [&](StringView candidate) {
+        if (!candidate.contains(directive, CaseSensitivity::CaseInsensitive))
+            return IterationDecision::Continue;
+
+        auto index = candidate.find('=');
+        if (!index.has_value())
+            return IterationDecision::Continue;
+
+        result = candidate.substring_view(*index + 1);
+        return IterationDecision::Break;
+    });
+
+    return result;
+}
+
+// https://httpwg.org/specs/rfc9110.html#field.date
+static Optional<UnixDateTime> parse_http_date(Optional<ByteString const&> date)
+{
+    // <day-name>, <day> <month> <year> <hour>:<minute>:<second> GMT
+    if (date.has_value())
+        return UnixDateTime::parse("%a, %d %b %Y %T GMT"sv, *date, true);
+    return {};
+}
+
+String serialize_url_for_cache_storage(URL::URL const& url)
+{
+    if (!url.fragment().has_value())
+        return url.serialize();
+
+    auto sanitized = url;
+    sanitized.set_fragment({});
+    return sanitized.serialize();
+}
+
+u64 create_cache_key(StringView url, StringView method)
+{
+    auto hasher = Crypto::Hash::SHA1::create();
+    hasher->update(url);
+    hasher->update(method);
+
+    auto digest = hasher->digest();
+    auto bytes = digest.bytes();
+
+    u64 result = 0;
+    result |= static_cast<u64>(bytes[0]) << 56;
+    result |= static_cast<u64>(bytes[1]) << 48;
+    result |= static_cast<u64>(bytes[2]) << 40;
+    result |= static_cast<u64>(bytes[3]) << 32;
+    result |= static_cast<u64>(bytes[4]) << 24;
+    result |= static_cast<u64>(bytes[5]) << 16;
+    result |= static_cast<u64>(bytes[6]) << 8;
+    result |= static_cast<u64>(bytes[7]);
+
+    return result;
+}
+
+// https://httpwg.org/specs/rfc9111.html#response.cacheability
+bool is_cacheable(StringView method, u32 status_code, HTTP::HeaderMap const& headers)
+{
+    // A cache MUST NOT store a response to a request unless:
+
+    // * the request method is understood by the cache;
+    if (!method.is_one_of("GET"sv, "HEAD"sv))
+        return false;
+
+    // * the response status code is final (see Section 15 of [HTTP]);
+    if (status_code < 200)
+        return false;
+
+    auto cache_control = headers.get("Cache-Control"sv);
+    if (!cache_control.has_value())
+        return false;
+
+    // * if the response status code is 206 or 304, or the must-understand cache directive (see Section 5.2.2.3) is
+    //   present: the cache understands the response status code;
+
+    // * the no-store cache directive is not present in the response (see Section 5.2.2.5);
+    if (cache_control->contains("no-store"sv, CaseSensitivity::CaseInsensitive))
+        return false;
+
+    // * if the cache is shared: the private response directive is either not present or allows a shared cache to store
+    //   a modified response; see Section 5.2.2.7);
+
+    // * if the cache is shared: the Authorization header field is not present in the request (see Section 11.6.2 of
+    //   [HTTP]) or a response directive is present that explicitly allows shared caching (see Section 3.5); and
+
+    // * the response contains at least one of the following:
+    //     - a public response directive (see Section 5.2.2.9);
+    //     - a private response directive, if the cache is not shared (see Section 5.2.2.7);
+    //     - an Expires header field (see Section 5.3);
+    //     - a max-age response directive (see Section 5.2.2.1);
+    //     - if the cache is shared: an s-maxage response directive (see Section 5.2.2.10);
+    //     - a cache extension that allows it to be cached (see Section 5.2.3); or
+    //     - a status code that is defined as heuristically cacheable (see Section 4.2.2).
+
+    // FIXME: Implement cache revalidation.
+    if (cache_control->contains("no-cache"sv, CaseSensitivity::CaseInsensitive))
+        return false;
+    if (cache_control->contains("revalidate"sv, CaseSensitivity::CaseInsensitive))
+        return false;
+
+    return true;
+}
+
+// https://httpwg.org/specs/rfc9111.html#storing.fields
+bool is_header_exempted_from_storage(StringView name)
+{
+    // Caches MUST include all received response header fields — including unrecognized ones — when storing a response;
+    // this assures that new HTTP header fields can be successfully deployed. However, the following exceptions are made:
+    return name.is_one_of_ignoring_ascii_case(
+        // * The Connection header field and fields whose names are listed in it are required by Section 7.6.1 of [HTTP]
+        //   to be removed before forwarding the message. This MAY be implemented by doing so before storage.
+        "Connection"sv,
+        "Keep-Alive"sv,
+        "Proxy-Connection"sv,
+        "TE"sv,
+        "Transfer-Encoding"sv,
+        "Upgrade"sv
+
+        // * Likewise, some fields' semantics require them to be removed before forwarding the message, and this MAY be
+        //   implemented by doing so before storage; see Section 7.6.1 of [HTTP] for some examples.
+
+        // * The no-cache (Section 5.2.2.4) and private (Section 5.2.2.7) cache directives can have arguments that
+        //   prevent storage of header fields by all caches and shared caches, respectively.
+
+        // * Header fields that are specific to the proxy that a cache uses when forwarding a request MUST NOT be stored,
+        //   unless the cache incorporates the identity of the proxy into the cache key. Effectively, this is limited to
+        //   Proxy-Authenticate (Section 11.7.1 of [HTTP]), Proxy-Authentication-Info (Section 11.7.3 of [HTTP]), and
+        //   Proxy-Authorization (Section 11.7.2 of [HTTP]).
+    );
+}
+
+// https://httpwg.org/specs/rfc9111.html#calculating.freshness.lifetime
+AK::Duration calculate_freshness_lifetime(HTTP::HeaderMap const& headers)
+{
+    // A cache can calculate the freshness lifetime (denoted as freshness_lifetime) of a response by evaluating the
+    // following rules and using the first match:
+
+    // * If the cache is shared and the s-maxage response directive (Section 5.2.2.10) is present, use its value, or
+
+    // * If the max-age response directive (Section 5.2.2.1) is present, use its value, or
+    if (auto cache_control = headers.get("Cache-Control"sv); cache_control.has_value()) {
+        if (auto max_age = extract_cache_control_directive(*cache_control, "max-age"sv); max_age.has_value()) {
+            if (auto seconds = max_age->to_number<i64>(); seconds.has_value())
+                return AK::Duration::from_seconds(*seconds);
+        }
+    }
+
+    // * If the Expires response header field (Section 5.3) is present, use its value minus the value of the Date response
+    //   header field (using the time the message was received if it is not present, as per Section 6.6.1 of [HTTP]), or
+    if (auto expires = parse_http_date(headers.get("Expires"sv)); expires.has_value()) {
+        auto date = parse_http_date(headers.get("Date"sv)).value_or_lazy_evaluated([]() {
+            return UnixDateTime::now();
+        });
+
+        return *expires - date;
+    }
+
+    // * Otherwise, no explicit expiration time is present in the response. A heuristic freshness lifetime might be
+    //   applicable; see Section 4.2.2.
+
+    return {};
+}
+
+// https://httpwg.org/specs/rfc9111.html#age.calculations
+AK::Duration calculate_age(HTTP::HeaderMap const& headers, UnixDateTime request_time, UnixDateTime response_time)
+{
+    // The term "age_value" denotes the value of the Age header field (Section 5.1), in a form appropriate for arithmetic
+    // operation; or 0, if not available.
+    AK::Duration age_value;
+
+    if (auto age = headers.get("Age"sv); age.has_value()) {
+        if (auto seconds = age->to_number<i64>(); seconds.has_value())
+            age_value = AK::Duration::from_seconds(*seconds);
+    }
+
+    // The term "now" means the current value of this implementation's clock (Section 5.6.7 of [HTTP]).
+    auto now = UnixDateTime::now();
+
+    // The term "date_value" denotes the value of the Date header field, in a form appropriate for arithmetic operations.
+    // See Section 6.6.1 of [HTTP] for the definition of the Date header field and for requirements regarding responses
+    // without it.
+    auto date_value = parse_http_date(headers.get("Date"sv)).value_or(now);
+
+    auto apparent_age = max(0LL, (response_time - date_value).to_seconds());
+
+    auto response_delay = response_time - request_time;
+    auto corrected_age_value = age_value + response_delay;
+
+    auto corrected_initial_age = max(apparent_age, corrected_age_value.to_seconds());
+
+    auto resident_time = (now - response_time).to_seconds();
+    auto current_age = corrected_initial_age + resident_time;
+
+    return AK::Duration::from_seconds(current_age);
+}
+
+// https://httpwg.org/specs/rfc9111.html#expiration.model
+bool is_response_fresh(AK::Duration freshness_lifetime, AK::Duration current_age)
+{
+    return freshness_lifetime > current_age;
+}
+
+}

Services/RequestServer/Cache/Utilities.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/StringView.h>
+#include <AK/Time.h>
+#include <AK/Types.h>
+#include <LibHTTP/HeaderMap.h>
+#include <LibURL/Forward.h>
+
+namespace RequestServer {
+
+String serialize_url_for_cache_storage(URL::URL const&);
+u64 create_cache_key(StringView url, StringView method);
+
+bool is_cacheable(StringView method, u32 status_code, HTTP::HeaderMap const&);
+bool is_header_exempted_from_storage(StringView name);
+
+AK::Duration calculate_freshness_lifetime(HTTP::HeaderMap const&);
+AK::Duration calculate_age(HTTP::HeaderMap const&, UnixDateTime request_time, UnixDateTime response_time);
+bool is_response_fresh(AK::Duration freshness_lifetime, AK::Duration current_age);
+
+}

Services/RequestServer/ConnectionFromClient.cpp

@@ -20,12 +20,15 @@
 #include <LibTextCodec/Decoder.h>
 #include <LibWebSocket/ConnectionInfo.h>
 #include <LibWebSocket/Message.h>
+#include <RequestServer/Cache/DiskCache.h>
 #include <RequestServer/ConnectionFromClient.h>
 #include <RequestServer/RequestClientEndpoint.h>
+
 #ifdef AK_OS_WINDOWS
 // needed because curl.h includes winsock2.h
 #    include <AK/Windows.h>
 #endif
+
 #include <curl/curl.h>
 
 namespace RequestServer {
@@ -42,6 +45,8 @@ static struct {
     bool validate_dnssec_locally = false;
 } g_dns_info;
 
+Optional<DiskCache> g_disk_cache;
+
 static WeakPtr<Resolver> s_resolver {};
 static NonnullRefPtr<Resolver> default_resolver()
 {
@@ -116,13 +121,17 @@ struct ConnectionFromClient::ActiveRequest : public Weakable<ActiveRequest> {
     bool got_all_headers { false };
     bool is_connect_only { false };
     size_t downloaded_so_far { 0 };
-    String url;
+    URL::URL url;
+    ByteString method;
     Optional<String> reason_phrase;
     ByteBuffer body;
     AllocatingMemoryStream send_buffer;
     NonnullRefPtr<Core::Notifier> write_notifier;
     bool done_fetching { false };
 
+    Optional<CacheEntryWriter&> cache_entry;
+    UnixDateTime request_start_time;
+
     ActiveRequest(ConnectionFromClient& client, CURLM* multi, CURL* easy, i32 request_id, int writer_fd)
         : multi(multi)
         , easy(easy)
@@ -130,6 +139,7 @@ struct ConnectionFromClient::ActiveRequest : public Weakable<ActiveRequest> {
         , client(client)
         , writer_fd(writer_fd)
         , write_notifier(Core::Notifier::construct(writer_fd, Core::NotificationType::Write))
+        , request_start_time(UnixDateTime::now())
     {
         write_notifier->set_enabled(false);
         write_notifier->on_activation = [this] {
@@ -163,6 +173,13 @@ struct ConnectionFromClient::ActiveRequest : public Weakable<ActiveRequest> {
             return {};
         }
 
+        if (cache_entry.has_value()) {
+            auto bytes_sent = bytes_to_send.span().slice(0, result.value());
+
+            if (cache_entry->write_data(bytes_sent).is_error())
+                cache_entry.clear();
+        }
+
         MUST(send_buffer.discard(result.value()));
         write_notifier->set_enabled(!send_buffer.is_eof());
         if (send_buffer.is_eof() && done_fetching)
@@ -193,6 +210,9 @@ struct ConnectionFromClient::ActiveRequest : public Weakable<ActiveRequest> {
 
         for (auto* string_list : curl_string_lists)
             curl_slist_free_all(string_list);
+
+        if (cache_entry.has_value())
+            (void)cache_entry->flush();
     }
 
     void flush_headers_if_needed()
@@ -204,6 +224,9 @@ struct ConnectionFromClient::ActiveRequest : public Weakable<ActiveRequest> {
         auto result = curl_easy_getinfo(easy, CURLINFO_RESPONSE_CODE, &http_status_code);
         VERIFY(result == CURLE_OK);
         client->async_headers_became_available(request_id, headers, http_status_code, reason_phrase);
+
+        if (g_disk_cache.has_value())
+            cache_entry = g_disk_cache->create_entry(url, method, http_status_code, reason_phrase, headers, request_start_time);
     }
 };
 
@@ -464,6 +487,33 @@ void ConnectionFromClient::start_request(i32, ByteString, URL::URL, HTTP::Header
 void ConnectionFromClient::start_request(i32 request_id, ByteString method, URL::URL url, HTTP::HeaderMap request_headers, ByteBuffer request_body, Core::ProxyData proxy_data)
 {
     dbgln_if(REQUESTSERVER_DEBUG, "RequestServer: start_request({}, {})", request_id, url);
+
+    if (g_disk_cache.has_value()) {
+        if (auto cache_entry = g_disk_cache->open_entry(url, method); cache_entry.has_value()) {
+            auto fds = MUST(Core::System::pipe2(O_NONBLOCK));
+            auto writer_fd = fds[1];
+            auto reader_fd = fds[0];
+
+            async_request_started(request_id, IPC::File::adopt_fd(reader_fd));
+            async_headers_became_available(request_id, cache_entry->headers(), cache_entry->status_code(), cache_entry->reason_phrase());
+
+            cache_entry->pipe_to(
+                writer_fd,
+                [this, request_id, writer_fd](auto bytes_sent) {
+                    // FIXME: Implement timing info for cache hits.
+                    async_request_finished(request_id, bytes_sent, {}, {});
+                    MUST(Core::System::close(writer_fd));
+                },
+                [this, request_id, writer_fd](auto bytes_sent) {
+                    // FIXME: We should switch to a network request automatically if reading from cache has failed.
+                    async_request_finished(request_id, bytes_sent, {}, Requests::NetworkError::CacheReadFailed);
+                    (void)Core::System::close(writer_fd);
+                });
+
+            return;
+        }
+    }
+
     auto host = url.serialized_host().to_byte_string();
 
     m_resolver->dns.lookup(host, DNS::Messages::Class::IN, { DNS::Messages::ResourceType::A, DNS::Messages::ResourceType::AAAA }, { .validate_dnssec_locally = g_dns_info.validate_dnssec_locally })
@@ -500,7 +550,8 @@ void ConnectionFromClient::start_request(i32 request_id, ByteString method, URL:
             async_request_started(request_id, IPC::File::adopt_fd(reader_fd));
 
             auto request = make<ActiveRequest>(*this, m_curl_multi, easy, request_id, writer_fd);
-            request->url = url.to_string();
+            request->url = url;
+            request->method = method;
 
             auto set_option = [easy](auto option, auto value) {
                 auto result = curl_easy_setopt(easy, option, value);
@@ -760,8 +811,6 @@ Messages::RequestServer::SetCertificateResponse ConnectionFromClient::set_certif
 
 void ConnectionFromClient::ensure_connection(URL::URL url, ::RequestServer::CacheLevel cache_level)
 {
-    auto const url_string_value = url.to_string();
-
     if (cache_level == CacheLevel::CreateConnection) {
         auto* easy = curl_easy_init();
         if (!easy) {
@@ -781,11 +830,11 @@ void ConnectionFromClient::ensure_connection(URL::URL url, ::RequestServer::Cach
         auto connect_only_request_id = get_random<i32>();
 
         auto request = make<ActiveRequest>(*this, m_curl_multi, easy, connect_only_request_id, 0);
-        request->url = url_string_value;
+        request->url = url;
         request->is_connect_only = true;
 
         set_option(CURLOPT_PRIVATE, request.ptr());
-        set_option(CURLOPT_URL, url_string_value.to_byte_string().characters());
+        set_option(CURLOPT_URL, url.to_byte_string().characters());
         set_option(CURLOPT_PORT, url.port_or_default());
         set_option(CURLOPT_CONNECTTIMEOUT, s_connect_timeout_seconds);
         set_option(CURLOPT_CONNECT_ONLY, 1L);
@@ -812,6 +861,12 @@ void ConnectionFromClient::ensure_connection(URL::URL url, ::RequestServer::Cach
     }
 }
 
+void ConnectionFromClient::clear_cache()
+{
+    if (g_disk_cache.has_value())
+        g_disk_cache->clear_cache();
+}
+
 void ConnectionFromClient::websocket_connect(i64 websocket_id, URL::URL url, ByteString origin, Vector<ByteString> protocols, Vector<ByteString> extensions, HTTP::HeaderMap additional_request_headers)
 {
     auto host = url.serialized_host().to_byte_string();

Services/RequestServer/ConnectionFromClient.h

@@ -49,6 +49,8 @@ private:
     virtual Messages::RequestServer::SetCertificateResponse set_certificate(i32, ByteString, ByteString) override;
     virtual void ensure_connection(URL::URL url, ::RequestServer::CacheLevel cache_level) override;
 
+    virtual void clear_cache() override;
+
     virtual void websocket_connect(i64 websocket_id, URL::URL, ByteString, Vector<ByteString>, Vector<ByteString>, HTTP::HeaderMap) override;
     virtual void websocket_send(i64 websocket_id, bool, ByteBuffer) override;
     virtual void websocket_close(i64 websocket_id, u16, ByteString) override;

Services/RequestServer/Forward.h

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+namespace RequestServer {
+
+class CacheEntry;
+class CacheEntryReader;
+class CacheEntryWriter;
+class CacheIndex;
+class DiskCache;
+
+}

Services/RequestServer/RequestServer.ipc

@@ -22,6 +22,8 @@ endpoint RequestServer
 
     ensure_connection(URL::URL url, ::RequestServer::CacheLevel cache_level) =|
 
+    clear_cache() =|
+
     // Websocket Connection API
     websocket_connect(i64 websocket_id, URL::URL url, ByteString origin, Vector<ByteString> protocols, Vector<ByteString> extensions, HTTP::HeaderMap additional_request_headers) =|
     websocket_send(i64 websocket_id, bool is_text, ByteBuffer data) =|

Services/RequestServer/main.cpp

@@ -14,6 +14,7 @@
 #include <LibCore/Process.h>
 #include <LibIPC/SingleServer.h>
 #include <LibMain/Main.h>
+#include <RequestServer/Cache/DiskCache.h>
 #include <RequestServer/ConnectionFromClient.h>
 
 #if defined(AK_OS_MACOS)
@@ -23,6 +24,7 @@
 namespace RequestServer {
 
 extern ByteString g_default_certificate_path;
+extern Optional<DiskCache> g_disk_cache;
 
 }
 
@@ -32,11 +34,13 @@ ErrorOr<int> ladybird_main(Main::Arguments arguments)
 
     Vector<ByteString> certificates;
     StringView mach_server_name;
+    bool enable_http_disk_cache = false;
     bool wait_for_debugger = false;
 
     Core::ArgsParser args_parser;
     args_parser.add_option(certificates, "Path to a certificate file", "certificate", 'C', "certificate");
     args_parser.add_option(mach_server_name, "Mach server name", "mach-server-name", 0, "mach_server_name");
+    args_parser.add_option(enable_http_disk_cache, "Enable HTTP disk cache", "enable-http-disk-cache");
     args_parser.add_option(wait_for_debugger, "Wait for debugger", "wait-for-debugger");
     args_parser.parse(arguments);
 
@@ -54,6 +58,13 @@ ErrorOr<int> ladybird_main(Main::Arguments arguments)
         Core::Platform::register_with_mach_server(mach_server_name);
 #endif
 
+    if (enable_http_disk_cache) {
+        if (auto cache = RequestServer::DiskCache::create(); cache.is_error())
+            warnln("Unable to create disk cache: {}", cache.error());
+        else
+            RequestServer::g_disk_cache = cache.release_value();
+    }
+
     auto client = TRY(IPC::take_over_accepted_client_from_system_server<RequestServer::ConnectionFromClient>());
 
     return event_loop.exec();

Tests/LibWeb/Ref/expected/position-absolute-fixed-nested-static-position.html

@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<style>
+div {
+  height: 100px;
+  width: 100px;
+  background-color: green;
+}
+</style>
+<div></div>

Tests/LibWeb/Ref/input/position-absolute-and-fixed-nested-static-position.html

@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<link rel="match" href="../expected/position-absolute-fixed-nested-static-position.html" />
+<style>
+div {
+  height: 100px;
+  width: 100px;
+}
+.absolute { position: absolute; }
+.fixed { position: fixed; }
+.outside { background-color: red; }
+.inside { background-color: orange; }
+.deep { background-color: yellow; }
+.deeper { background-color: green; }
+</style>
+<div class="outside">
+  <div class="fixed inside">
+    <div class="deep">
+      <div class="absolute deeper"></div>
+    </div>
+  </div>
+</div>