LibWeb/IDB: Implement clone_in_realm

Author: https://github.com/stelar7
Commit: https://github.com/LadybirdBrowser/ladybird/commit/499548c3d0f
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4317
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/kennethmyhra ✅

Libraries/LibWeb/IndexedDB/Internal/Algorithms.cpp

@@ -15,6 +15,7 @@
 #include <LibWeb/DOM/EventDispatcher.h>
 #include <LibWeb/HTML/EventNames.h>
 #include <LibWeb/HTML/Scripting/TemporaryExecutionContext.h>
+#include <LibWeb/HTML/StructuredSerialize.h>
 #include <LibWeb/IndexedDB/IDBDatabase.h>
 #include <LibWeb/IndexedDB/IDBRequest.h>
 #include <LibWeb/IndexedDB/IDBTransaction.h>
@@ -790,4 +791,28 @@ void commit_a_transaction(JS::Realm& realm, GC::Ref<IDBTransaction> transaction)
     }));
 }
 
+// https://w3c.github.io/IndexedDB/#clone
+WebIDL::ExceptionOr<JS::Value> clone_in_realm(JS::Realm& target_realm, JS::Value value, GC::Ref<IDBTransaction> transaction)
+{
+    auto& vm = target_realm.vm();
+
+    // 1. Assert: transaction’s state is active.
+    VERIFY(transaction->state() == IDBTransaction::TransactionState::Active);
+
+    // 2. Set transaction’s state to inactive.
+    transaction->set_state(IDBTransaction::TransactionState::Inactive);
+
+    // 3. Let serialized be ? StructuredSerializeForStorage(value).
+    auto serialized = TRY(HTML::structured_serialize_for_storage(vm, value));
+
+    // 4. Let clone be ? StructuredDeserialize(serialized, targetRealm).
+    auto clone = TRY(HTML::structured_deserialize(vm, serialized, target_realm));
+
+    // 5. Set transaction’s state to active.
+    transaction->set_state(IDBTransaction::TransactionState::Active);
+
+    // 6. Return clone.
+    return clone;
+}
+
 }