LibWeb/HTML: Move WindowOrWorkerGlobalScope code into a mixin class

This will allow us to easily share the implementations of these methods
between Window and WorkerGlobalScope. The mixin class mirrors what I
already did for the Fetch API's Body mixin in 5ad62833.

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -303,6 +303,7 @@ set(SOURCES
     HTML/Timer.cpp
     HTML/Window.cpp
     HTML/WindowEventHandlers.cpp
+    HTML/WindowOrWorkerGlobalScope.cpp
     HTML/WindowProxy.cpp
     HTML/Worker.cpp
     HTML/WorkerDebugConsoleClient.cpp

Userland/Libraries/LibWeb/HTML/WindowOrWorkerGlobalScope.cpp

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2022, Andrew Kaster <akaster@serenityos.org>
+ * Copyright (c) 2023, Linus Groh <linusg@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Base64.h>
+#include <AK/String.h>
+#include <AK/Utf8View.h>
+#include <AK/Vector.h>
+#include <LibTextCodec/Decoder.h>
+#include <LibWeb/Forward.h>
+#include <LibWeb/HTML/WindowOrWorkerGlobalScope.h>
+#include <LibWeb/WebIDL/DOMException.h>
+#include <LibWeb/WebIDL/ExceptionOr.h>
+
+namespace Web::HTML {
+
+WindowOrWorkerGlobalScopeMixin::~WindowOrWorkerGlobalScopeMixin() = default;
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#dom-origin
+WebIDL::ExceptionOr<String> WindowOrWorkerGlobalScopeMixin::origin() const
+{
+    auto& vm = this_impl().vm();
+
+    // The origin getter steps are to return this's relevant settings object's origin, serialized.
+    return TRY_OR_THROW_OOM(vm, String::from_deprecated_string(relevant_settings_object(this_impl()).origin().serialize()));
+}
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#dom-issecurecontext
+bool WindowOrWorkerGlobalScopeMixin::is_secure_context() const
+{
+    // The isSecureContext getter steps are to return true if this's relevant settings object is a secure context, or false otherwise.
+    return HTML::is_secure_context(relevant_settings_object(this_impl()));
+}
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#dom-crossoriginisolated
+bool WindowOrWorkerGlobalScopeMixin::cross_origin_isolated() const
+{
+    // The crossOriginIsolated getter steps are to return this's relevant settings object's cross-origin isolated capability.
+    return relevant_settings_object(this_impl()).cross_origin_isolated_capability() == CanUseCrossOriginIsolatedAPIs::Yes;
+}
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#dom-btoa
+WebIDL::ExceptionOr<String> WindowOrWorkerGlobalScopeMixin::btoa(String const& data) const
+{
+    auto& vm = this_impl().vm();
+    auto& realm = *vm.current_realm();
+
+    // The btoa(data) method must throw an "InvalidCharacterError" DOMException if data contains any character whose code point is greater than U+00FF.
+    Vector<u8> byte_string;
+    byte_string.ensure_capacity(data.bytes().size());
+    for (u32 code_point : Utf8View(data)) {
+        if (code_point > 0xff)
+            return WebIDL::InvalidCharacterError::create(realm, "Data contains characters outside the range U+0000 and U+00FF");
+        byte_string.append(code_point);
+    }
+
+    // Otherwise, the user agent must convert data to a byte sequence whose nth byte is the eight-bit representation of the nth code point of data,
+    // and then must apply forgiving-base64 encode to that byte sequence and return the result.
+    return TRY_OR_THROW_OOM(vm, encode_base64(byte_string.span()));
+}
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#dom-atob
+WebIDL::ExceptionOr<String> WindowOrWorkerGlobalScopeMixin::atob(String const& data) const
+{
+    auto& vm = this_impl().vm();
+    auto& realm = *vm.current_realm();
+
+    // 1. Let decodedData be the result of running forgiving-base64 decode on data.
+    auto decoded_data = decode_base64(data.bytes_as_string_view());
+
+    // 2. If decodedData is failure, then throw an "InvalidCharacterError" DOMException.
+    if (decoded_data.is_error())
+        return WebIDL::InvalidCharacterError::create(realm, "Input string is not valid base64 data");
+
+    // 3. Return decodedData.
+    // decode_base64() returns a byte string. LibJS uses UTF-8 for strings. Use Latin1Decoder to convert bytes 128-255 to UTF-8.
+    auto decoder = TextCodec::decoder_for("windows-1252"sv);
+    VERIFY(decoder.has_value());
+    return TRY_OR_THROW_OOM(vm, decoder->to_utf8(decoded_data.value()));
+}
+
+}

Userland/Libraries/LibWeb/HTML/WindowOrWorkerGlobalScope.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2023, Linus Groh <linusg@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Forward.h>
+#include <LibWeb/Bindings/PlatformObject.h>
+#include <LibWeb/Forward.h>
+
+namespace Web::HTML {
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#windoworworkerglobalscope
+class WindowOrWorkerGlobalScopeMixin {
+public:
+    virtual ~WindowOrWorkerGlobalScopeMixin();
+
+    virtual Bindings::PlatformObject& this_impl() = 0;
+    virtual Bindings::PlatformObject const& this_impl() const = 0;
+
+    // JS API functions
+    WebIDL::ExceptionOr<String> origin() const;
+    bool is_secure_context() const;
+    bool cross_origin_isolated() const;
+    WebIDL::ExceptionOr<String> btoa(String const& data) const;
+    WebIDL::ExceptionOr<String> atob(String const& data) const;
+};
+
+}

Userland/Libraries/LibWeb/HTML/WorkerGlobalScope.cpp

@@ -1,26 +1,18 @@
 /*
  * Copyright (c) 2022, Andrew Kaster <akaster@serenityos.org>
- * Copyright (c) 2023, Linus Groh <linusg@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <AK/Base64.h>
-#include <AK/DeprecatedString.h>
-#include <AK/Utf8View.h>
 #include <AK/Vector.h>
-#include <LibJS/Runtime/Completion.h>
-#include <LibTextCodec/Decoder.h>
 #include <LibWeb/Bindings/ExceptionOrUtils.h>
 #include <LibWeb/Bindings/WorkerGlobalScopePrototype.h>
 #include <LibWeb/Forward.h>
 #include <LibWeb/HTML/EventHandler.h>
 #include <LibWeb/HTML/EventNames.h>
-#include <LibWeb/HTML/Window.h>
 #include <LibWeb/HTML/WorkerGlobalScope.h>
 #include <LibWeb/HTML/WorkerLocation.h>
 #include <LibWeb/HTML/WorkerNavigator.h>
-#include <LibWeb/WebIDL/DOMException.h>
 
 namespace Web::HTML {
 
@@ -104,67 +96,4 @@ JS::NonnullGCPtr<WorkerNavigator> WorkerGlobalScope::navigator() const
 ENUMERATE_WORKER_GLOBAL_SCOPE_EVENT_HANDLERS(__ENUMERATE)
 #undef __ENUMERATE
 
-// https://html.spec.whatwg.org/multipage/webappapis.html#dom-origin
-WebIDL::ExceptionOr<String> WorkerGlobalScope::origin() const
-{
-    auto& vm = this->vm();
-
-    // The origin getter steps are to return this's relevant settings object's origin, serialized.
-    return TRY_OR_THROW_OOM(vm, String::from_deprecated_string(relevant_settings_object(this_impl()).origin().serialize()));
-}
-
-// https://html.spec.whatwg.org/multipage/webappapis.html#dom-issecurecontext
-bool WorkerGlobalScope::is_secure_context() const
-{
-    // The isSecureContext getter steps are to return true if this's relevant settings object is a secure context, or false otherwise.
-    return HTML::is_secure_context(relevant_settings_object(*this));
-}
-
-// https://html.spec.whatwg.org/multipage/webappapis.html#dom-crossoriginisolated
-bool WorkerGlobalScope::cross_origin_isolated() const
-{
-    // The crossOriginIsolated getter steps are to return this's relevant settings object's cross-origin isolated capability.
-    return relevant_settings_object(*this).cross_origin_isolated_capability() == CanUseCrossOriginIsolatedAPIs::Yes;
-}
-
-// https://html.spec.whatwg.org/multipage/webappapis.html#dom-btoa
-WebIDL::ExceptionOr<String> WorkerGlobalScope::btoa(String const& data) const
-{
-    // FIXME: This is the same as the implementation in Bindings/WindowObject.cpp
-    //     Find a way to share this implementation, since they come from the same mixin.
-
-    // The btoa(data) method must throw an "InvalidCharacterError" DOMException if data contains any character whose code point is greater than U+00FF.
-    Vector<u8> byte_string;
-    byte_string.ensure_capacity(data.bytes().size());
-    for (u32 code_point : Utf8View(data)) {
-        if (code_point > 0xff)
-            return WebIDL::InvalidCharacterError::create(realm(), "Data contains characters outside the range U+0000 and U+00FF");
-        byte_string.append(code_point);
-    }
-
-    // Otherwise, the user agent must convert data to a byte sequence whose nth byte is the eight-bit representation of the nth code point of data,
-    // and then must apply forgiving-base64 encode to that byte sequence and return the result.
-    return TRY_OR_THROW_OOM(vm(), encode_base64(byte_string.span()));
-}
-
-// https://html.spec.whatwg.org/multipage/webappapis.html#dom-atob
-WebIDL::ExceptionOr<String> WorkerGlobalScope::atob(String const& data) const
-{
-    // FIXME: This is the same as the implementation in Bindings/WindowObject.cpp
-    //     Find a way to share this implementation, since they come from the same mixin.
-
-    // 1. Let decodedData be the result of running forgiving-base64 decode on data.
-    auto decoded_data = decode_base64(data.bytes_as_string_view());
-
-    // 2. If decodedData is failure, then throw an "InvalidCharacterError" DOMException.
-    if (decoded_data.is_error())
-        return WebIDL::InvalidCharacterError::create(realm(), "Input string is not valid base64 data");
-
-    // 3. Return decodedData.
-    // decode_base64() returns a byte string. LibJS uses UTF-8 for strings. Use Latin1Decoder to convert bytes 128-255 to UTF-8.
-    auto decoder = TextCodec::decoder_for("windows-1252"sv);
-    VERIFY(decoder.has_value());
-    return TRY_OR_THROW_OOM(vm(), decoder->to_utf8(decoded_data.value()));
-}
-
 }

Userland/Libraries/LibWeb/HTML/WorkerGlobalScope.h

@@ -11,6 +11,7 @@
 #include <AK/URL.h>
 #include <LibWeb/DOM/EventTarget.h>
 #include <LibWeb/Forward.h>
+#include <LibWeb/HTML/WindowOrWorkerGlobalScope.h>
 #include <LibWeb/HTML/WorkerLocation.h>
 #include <LibWeb/HTML/WorkerNavigator.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
@@ -28,12 +29,18 @@ namespace Web::HTML {
 // https://html.spec.whatwg.org/multipage/workers.html#the-workerglobalscope-common-interface
 // WorkerGlobalScope is the base class of each real WorkerGlobalScope that will be created when the
 // user agent runs the run a worker algorithm.
-class WorkerGlobalScope : public DOM::EventTarget {
+class WorkerGlobalScope
+    : public DOM::EventTarget
+    , public WindowOrWorkerGlobalScopeMixin {
     WEB_PLATFORM_OBJECT(WorkerGlobalScope, DOM::EventTarget);
 
 public:
     virtual ~WorkerGlobalScope() override;
 
+    // ^WindowOrWorkerGlobalScopeMixin
+    virtual Bindings::PlatformObject& this_impl() override { return *this; }
+    virtual Bindings::PlatformObject const& this_impl() const override { return *this; }
+
     // Following methods are from the WorkerGlobalScope IDL definition
     // https://html.spec.whatwg.org/multipage/workers.html#the-workerglobalscope-common-interface
 
@@ -51,15 +58,6 @@ public:
     ENUMERATE_WORKER_GLOBAL_SCOPE_EVENT_HANDLERS(__ENUMERATE)
 #undef __ENUMERATE
 
-    // Following methods are from the WindowOrWorkerGlobalScope mixin
-    // https://html.spec.whatwg.org/multipage/webappapis.html#windoworworkerglobalscope-mixin
-
-    WebIDL::ExceptionOr<String> origin() const;
-    bool is_secure_context() const;
-    bool cross_origin_isolated() const;
-    WebIDL::ExceptionOr<String> btoa(String const& data) const;
-    WebIDL::ExceptionOr<String> atob(String const& data) const;
-
     // Non-IDL public methods
 
     AK::URL const& url() const { return m_url.value(); }