LibWeb: Make PolicyContainer GC allocated

This is required to store Content Security Policies, as their
Directives are implemented as subclasses with overridden virtual
functions. Thus, they cannot be stored as generic Directive classes, as
it'll lose the ability to call overridden functions when they are
copied.

Libraries/LibWeb/HTML/PolicyContainers.cpp

@@ -1,29 +1,69 @@
 /*
  * Copyright (c) 2024, Andrew Kaster <akaster@serenityos.org>
+ * Copyright (c) 2025, Luke Wilde <luke@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <LibIPC/Decoder.h>
-#include <LibIPC/Encoder.h>
+#include <LibJS/Runtime/Realm.h>
+#include <LibURL/URL.h>
+#include <LibWeb/Fetch/Infrastructure/URL.h>
 #include <LibWeb/HTML/PolicyContainers.h>
+#include <LibWeb/HTML/SerializedPolicyContainer.h>
 
-namespace IPC {
+namespace Web::HTML {
 
-template<>
-ErrorOr<void> encode(IPC::Encoder& encoder, Web::HTML::PolicyContainer const& policy_container)
+GC_DEFINE_ALLOCATOR(PolicyContainer);
+
+PolicyContainer::PolicyContainer(JS::Realm&)
 {
-    TRY(encode(encoder, policy_container.referrer_policy));
-
-    return {};
 }
 
-template<>
-ErrorOr<Web::HTML::PolicyContainer> decode(IPC::Decoder& decoder)
+// https://html.spec.whatwg.org/multipage/browsers.html#requires-storing-the-policy-container-in-history
+bool url_requires_storing_the_policy_container_in_history(URL::URL const& url)
 {
-    auto referrer_policy = TRY(decoder.decode<Web::ReferrerPolicy::ReferrerPolicy>());
+    // 1. If url's scheme is "blob", then return false.
+    if (url.scheme() == "blob"sv)
+        return false;
 
-    return Web::HTML::PolicyContainer { .referrer_policy = referrer_policy };
+    // 2. If url is local, then return true.
+    // 3. Return false.
+    return Fetch::Infrastructure::is_local_url(url);
+}
+
+GC::Ref<PolicyContainer> create_a_policy_container_from_serialized_policy_container(JS::Realm& realm, SerializedPolicyContainer const& serialized_policy_container)
+{
+    GC::Ref<PolicyContainer> result = realm.create<PolicyContainer>(realm);
+    result->embedder_policy = serialized_policy_container.embedder_policy;
+    result->referrer_policy = serialized_policy_container.referrer_policy;
+    return result;
+}
+
+// https://html.spec.whatwg.org/multipage/browsers.html#clone-a-policy-container
+GC::Ref<PolicyContainer> PolicyContainer::clone(JS::Realm& realm) const
+{
+    // 1. Let clone be a new policy container.
+    auto clone = realm.create<PolicyContainer>(realm);
+
+    // FIXME: 2. For each policy in policyContainer's CSP list, append a copy of policy into clone's CSP list.
+
+    // 3. Set clone's embedder policy to a copy of policyContainer's embedder policy.
+    // NOTE: This is a C++ copy.
+    clone->embedder_policy = embedder_policy;
+
+    // 4. Set clone's referrer policy to policyContainer's referrer policy.
+    clone->referrer_policy = referrer_policy;
+
+    // 5. Return clone.
+    return clone;
+}
+
+SerializedPolicyContainer PolicyContainer::serialize() const
+{
+    return SerializedPolicyContainer {
+        .embedder_policy = embedder_policy,
+        .referrer_policy = referrer_policy,
+    };
 }
 
 }