LibWeb: Implement transfer for Resizable/ArrayBuffer

Implement transfer logic for ArrayBuffer and ResizableArrayBuffer.

Change TransferDataHolder data type to Vector<u32> to reuse existing
serialization infrastructure.

Fix 5 WPT tests in `window-postmessage.window.html` that relates to
transport.
Fix `LibWeb/Text/input/Worker/Worker-postMessage-transfer.html`.
The latter is currently ignored due to flakiness, no rebaseline is
needed.

During serialization with transfer, initialize memory with known index
and initialize Serializer at position that dependent on the memory.
This is mandatory to make ArrayBuffer transport to work. It also happens
to fix 4 WPT tests, that are related to curcular references during
serialization.

Libraries/LibWeb/HTML/StructuredSerialize.cpp

@@ -16,6 +16,7 @@
 #include <LibJS/Forward.h>
 #include <LibJS/Runtime/Array.h>
 #include <LibJS/Runtime/ArrayBuffer.h>
+#include <LibJS/Runtime/ArrayBufferConstructor.h>
 #include <LibJS/Runtime/BigInt.h>
 #include <LibJS/Runtime/BigIntObject.h>
 #include <LibJS/Runtime/BooleanObject.h>
@@ -153,6 +154,7 @@ class Serializer {
     Serializer(JS::VM& vm, SerializationMemory& memory, bool for_storage)
         : m_vm(vm)
         , m_memory(memory)
+        , m_next_id(memory.size())
         , m_for_storage(for_storage)
     {
     }
@@ -635,14 +637,16 @@ WebIDL::ExceptionOr<void> serialize_viewed_array_buffer(JS::VM& vm, Vector<u32>&
     }
 
     // 2. Let buffer be the value of value's [[ViewedArrayBuffer]] internal slot.
-    auto* buffer = view.viewed_array_buffer();
+    JS::Value buffer = view.viewed_array_buffer();
 
     // 3. Let bufferSerialized be ? StructuredSerializeInternal(buffer, forStorage, memory).
-    auto buffer_serialized = TRY(structured_serialize_internal(vm, JS::Value(buffer), for_storage, memory));
+    auto buffer_serialized = TRY(structured_serialize_internal(vm, buffer, for_storage, memory));
 
     // 4. Assert: bufferSerialized.[[Type]] is "ArrayBuffer", "ResizableArrayBuffer", "SharedArrayBuffer", or "GrowableSharedArrayBuffer".
     // NOTE: We currently only implement this for ArrayBuffer
-    VERIFY(buffer_serialized[0] == ValueTag::ArrayBuffer);
+    // NOTE: Object reference + memory check is required when ArrayBuffer is transfered.
+    auto tag = buffer_serialized[0];
+    VERIFY(tag == ValueTag::ArrayBuffer || (tag == ValueTag::ObjectReference && memory.contains(buffer)));
 
     // 5. If value has a [[DataView]] internal slot, then set serialized to { [[Type]]: "ArrayBufferView", [[Constructor]]: "DataView",
     //    [[ArrayBufferSerialized]]: bufferSerialized, [[ByteLength]]: value.[[ByteLength]], [[ByteOffset]]: value.[[ByteOffset]] }.
@@ -1114,14 +1118,18 @@ WebIDL::ExceptionOr<SerializedTransferRecord> structured_serialize_with_transfer
 
     // 2. For each transferable of transferList:
     for (auto const& transferable : transfer_list) {
+        auto is_array_buffer = is<JS::ArrayBuffer>(*transferable);
 
         // 1. If transferable has neither an [[ArrayBufferData]] internal slot nor a [[Detached]] internal slot, then throw a "DataCloneError" DOMException.
-        // FIXME: Handle transferring ArrayBufferData objects
-        if (!is<Bindings::Transferable>(*transferable)) {
+        // FIXME: Handle transferring objects with [[Detached]] internal slot.
+        if (!is_array_buffer && !is<Bindings::Transferable>(*transferable)) {
             return WebIDL::DataCloneError::create(*vm.current_realm(), "Cannot transfer type"_string);
         }
 
-        // FIXME: 2. If transferable has an [[ArrayBufferData]] internal slot and IsSharedArrayBuffer(transferable) is true, then throw a "DataCloneError" DOMException.
+        // 2. If transferable has an [[ArrayBufferData]] internal slot and IsSharedArrayBuffer(transferable) is true, then throw a "DataCloneError" DOMException.
+        if (is_array_buffer && dynamic_cast<JS::ArrayBuffer&>(*transferable).is_shared_array_buffer()) {
+            return WebIDL::DataCloneError::create(*vm.current_realm(), "Cannot transfer shared array buffer"_string);
+        }
 
         // 3. If memory[transferable] exists, then throw a "DataCloneError" DOMException.
         auto transferable_value = JS::Value(transferable);
@@ -1130,7 +1138,7 @@ WebIDL::ExceptionOr<SerializedTransferRecord> structured_serialize_with_transfer
         }
 
         // 4. Set memory[transferable] to { [[Type]]: an uninitialized value }.
-        memory.set(GC::make_root(transferable_value), NumericLimits<u32>::max());
+        memory.set(GC::make_root(transferable_value), memory.size());
     }
 
     // 3. Let serialized be ? StructuredSerializeInternal(value, false, memory).
@@ -1142,7 +1150,13 @@ WebIDL::ExceptionOr<SerializedTransferRecord> structured_serialize_with_transfer
 
     // 5. For each transferable of transferList:
     for (auto& transferable : transfer_list) {
-        // 1. FIXME: If transferable has an [[ArrayBufferData]] internal slot and IsDetachedBuffer(transferable) is true, then throw a "DataCloneError" DOMException.
+        auto is_array_buffer = is<JS::ArrayBuffer>(*transferable);
+        auto is_detached = is_array_buffer && dynamic_cast<JS::ArrayBuffer&>(*transferable).is_detached();
+
+        // 1. If transferable has an [[ArrayBufferData]] internal slot and IsDetachedBuffer(transferable) is true, then throw a "DataCloneError" DOMException.
+        if (is_detached) {
+            return WebIDL::DataCloneError::create(*vm.current_realm(), "Cannot transfer detached buffer"_string);
+        }
 
         // 2. If transferable has a [[Detached]] internal slot and transferable.[[Detached]] is true, then throw a "DataCloneError" DOMException.
         if (is<Bindings::Transferable>(*transferable)) {
@@ -1156,8 +1170,32 @@ WebIDL::ExceptionOr<SerializedTransferRecord> structured_serialize_with_transfer
         // IMPLEMENTATION DEFINED: We just create a data holder here, our memory holds indices into the SerializationRecord
         TransferDataHolder data_holder;
 
-        // FIXME 4. If transferable has an [[ArrayBufferData]] internal slot, then:
-        if (false) {
+        // 4. If transferable has an [[ArrayBufferData]] internal slot, then:
+        if (is_array_buffer) {
+            // 1. If transferable has an [[ArrayBufferMaxByteLength]] internal slot, then:
+            auto& array_buffer = dynamic_cast<JS::ArrayBuffer&>(*transferable);
+            if (!array_buffer.is_fixed_length()) {
+                // 1. Set dataHolder.[[Type]] to "ResizableArrayBuffer".
+                // 2. Set dataHolder.[[ArrayBufferData]] to transferable.[[ArrayBufferData]].
+                // 3. Set dataHolder.[[ArrayBufferByteLength]] to transferable.[[ArrayBufferByteLength]].
+                // 4. Set dataHolder.[[ArrayBufferMaxByteLength]] to transferable.[[ArrayBufferMaxByteLength]].
+                serialize_enum<TransferType>(data_holder.data, TransferType::ResizableArrayBuffer);
+                MUST(serialize_bytes(vm, data_holder.data, array_buffer.buffer().bytes())); // serializes both byte length and bytes
+                serialize_primitive_type<size_t>(data_holder.data, array_buffer.max_byte_length());
+            }
+
+            // 2. Otherwise:
+            else {
+                // 1. Set dataHolder.[[Type]] to "ArrayBuffer".
+                // 2. Set dataHolder.[[ArrayBufferData]] to transferable.[[ArrayBufferData]].
+                // 3. Set dataHolder.[[ArrayBufferByteLength]] to transferable.[[ArrayBufferByteLength]].
+                serialize_enum<TransferType>(data_holder.data, TransferType::ArrayBuffer);
+                MUST(serialize_bytes(vm, data_holder.data, array_buffer.buffer().bytes())); // serializes both byte length and bytes
+            }
+
+            // 3. Perform ? DetachArrayBuffer(transferable).
+            // NOTE: Specifications can use the [[ArrayBufferDetachKey]] internal slot to prevent ArrayBuffers from being detached. This is used in WebAssembly JavaScript Interface, for example. See: https://html.spec.whatwg.org/multipage/references.html#refsWASMJS
+            MUST(JS::detach_array_buffer(vm, array_buffer));
         }
 
         // 5. Otherwise:
@@ -1170,7 +1208,7 @@ WebIDL::ExceptionOr<SerializedTransferRecord> structured_serialize_with_transfer
             auto interface_name = transferable_object.primary_interface();
 
             // 3. Set dataHolder.[[Type]] to interfaceName.
-            data_holder.data.append(to_underlying(interface_name));
+            serialize_enum<TransferType>(data_holder.data, interface_name);
 
             // 4. Perform the appropriate transfer steps for the interface identified by interfaceName, given transferable and dataHolder.
             TRY(transferable_object.transfer_steps(data_holder));
@@ -1187,15 +1225,15 @@ WebIDL::ExceptionOr<SerializedTransferRecord> structured_serialize_with_transfer
     return SerializedTransferRecord { .serialized = move(serialized), .transfer_data_holders = move(transfer_data_holders) };
 }
 
-static bool is_interface_exposed_on_target_realm(u8 name, JS::Realm& realm)
+static bool is_interface_exposed_on_target_realm(TransferType name, JS::Realm& realm)
 {
     auto const& intrinsics = Bindings::host_defined_intrinsics(realm);
-    switch (static_cast<TransferType>(name)) {
+    switch (name) {
     case TransferType::MessagePort:
         return intrinsics.is_exposed("MessagePort"sv);
         break;
     default:
-        dbgln("Unknown interface type for transfer: {}", name);
+        dbgln("Unknown interface type for transfer: {}", to_underlying(name));
         break;
     }
     return false;
@@ -1209,6 +1247,9 @@ static WebIDL::ExceptionOr<GC::Ref<Bindings::PlatformObject>> create_transferred
         TRY(message_port->transfer_receiving_steps(transfer_data_holder));
         return message_port;
     }
+    default:
+        dbgln("Unknown interface type for transfer: {}", to_underlying(name));
+        break;
     }
     VERIFY_NOT_REACHED();
 }
@@ -1226,39 +1267,54 @@ WebIDL::ExceptionOr<DeserializedTransferRecord> structured_deserialize_with_tran
 
     // 3. For each transferDataHolder of serializeWithTransferResult.[[TransferDataHolders]]:
     for (auto& transfer_data_holder : serialize_with_transfer_result.transfer_data_holders) {
+        if(transfer_data_holder.data.is_empty())
+            continue;
+
         // 1. Let value be an uninitialized value.
         JS::Value value;
 
-        // FIXME: 2. If transferDataHolder.[[Type]] is "ArrayBuffer", then set value to a new ArrayBuffer object in targetRealm
+        size_t data_holder_position = 0;
+        auto type = deserialize_primitive_type<TransferType>(transfer_data_holder.data.span(), data_holder_position);
+
+        // 2. If transferDataHolder.[[Type]] is "ArrayBuffer", then set value to a new ArrayBuffer object in targetRealm
         //    whose [[ArrayBufferData]] internal slot value is transferDataHolder.[[ArrayBufferData]], and
         //    whose [[ArrayBufferByteLength]] internal slot value is transferDataHolder.[[ArrayBufferByteLength]].
         // NOTE: In cases where the original memory occupied by [[ArrayBufferData]] is accessible during the deserialization,
         //       this step is unlikely to throw an exception, as no new memory needs to be allocated: the memory occupied by
         //       [[ArrayBufferData]] is instead just getting transferred into the new ArrayBuffer. This could be true, for example,
         //       when both the source and target realms are in the same process.
-        if (false) {
+        if (type == TransferType::ArrayBuffer) {
+            auto bytes = TRY(deserialize_bytes(vm, transfer_data_holder.data, data_holder_position));
+            JS::ArrayBuffer* data = TRY(JS::allocate_array_buffer(vm, target_realm.intrinsics().array_buffer_constructor(), bytes.size()));
+            bytes.span().copy_to(data->buffer().span());
+            value = JS::Value(data);
         }
 
-        // FIXME: 3. Otherwise, if transferDataHolder.[[Type]] is "ResizableArrayBuffer", then set value to a new ArrayBuffer object
+        // 3. Otherwise, if transferDataHolder.[[Type]] is "ResizableArrayBuffer", then set value to a new ArrayBuffer object
         //     in targetRealm whose [[ArrayBufferData]] internal slot value is transferDataHolder.[[ArrayBufferData]], whose
         //     [[ArrayBufferByteLength]] internal slot value is transferDataHolder.[[ArrayBufferByteLength]], and whose
         //     [[ArrayBufferMaxByteLength]] internal slot value is transferDataHolder.[[ArrayBufferMaxByteLength]].
         // NOTE: For the same reason as the previous step, this step is also unlikely to throw an exception.
-        else if (false) {
+        else if (type == TransferType::ResizableArrayBuffer) {
+            auto bytes = TRY(deserialize_bytes(vm, transfer_data_holder.data, data_holder_position));
+            auto max_byte_length = deserialize_primitive_type<size_t>(transfer_data_holder.data, data_holder_position);
+            JS::ArrayBuffer* data = TRY(JS::allocate_array_buffer(vm, target_realm.intrinsics().array_buffer_constructor(), bytes.size()));
+            data->set_max_byte_length(max_byte_length);
+            bytes.span().copy_to(data->buffer().span());
+            value = JS::Value(data);
         }
 
         // 4. Otherwise:
         else {
             // 1. Let interfaceName be transferDataHolder.[[Type]].
-            u8 const interface_name = transfer_data_holder.data.take_first();
-
             // 2. If the interface identified by interfaceName is not exposed in targetRealm, then throw a "DataCloneError" DOMException.
-            if (!is_interface_exposed_on_target_realm(interface_name, target_realm))
+            if (!is_interface_exposed_on_target_realm(type, target_realm))
                 return WebIDL::DataCloneError::create(target_realm, "Unknown type transferred"_string);
 
             // 3. Set value to a new instance of the interface identified by interfaceName, created in targetRealm.
             // 4. Perform the appropriate transfer-receiving steps for the interface identified by interfaceName given transferDataHolder and value.
-            value = TRY(create_transferred_value(static_cast<TransferType>(interface_name), target_realm, transfer_data_holder));
+            transfer_data_holder.data.remove(0, data_holder_position);
+            value = TRY(create_transferred_value(type, target_realm, transfer_data_holder));
         }
 
         // 5. Set memory[transferDataHolder] to value.
@@ -1351,7 +1407,7 @@ ErrorOr<void> encode(Encoder& encoder, ::Web::HTML::SerializedTransferRecord con
 template<>
 ErrorOr<::Web::HTML::TransferDataHolder> decode(Decoder& decoder)
 {
-    auto data = TRY(decoder.decode<Vector<u8>>());
+    auto data = TRY(decoder.decode<Vector<u32>>());
     auto fds = TRY(decoder.decode<Vector<IPC::File>>());
     return ::Web::HTML::TransferDataHolder { move(data), move(fds) };
 }

Libraries/LibWeb/HTML/StructuredSerialize.h

@@ -25,7 +25,7 @@
 namespace Web::HTML {
 
 struct TransferDataHolder {
-    Vector<u8> data;
+    Vector<u32> data;
     Vector<IPC::File> fds;
 };
 
@@ -46,6 +46,8 @@ struct DeserializedRecord {
 
 enum class TransferType : u8 {
     MessagePort,
+    ArrayBuffer,
+    ResizableArrayBuffer,
 };
 
 WebIDL::ExceptionOr<SerializationRecord> structured_serialize(JS::VM& vm, JS::Value);

Tests/LibWeb/Text/expected/Worker/Worker-postMessage-transfer.txt

@@ -1 +1,3 @@
+Buffer length before transfer: 12
+Buffer length after transfer: 0
 Message received from worker: Hello, world

Tests/LibWeb/Text/expected/wpt-import/html/infrastructure/safe-passing-of-structured-data/window-postmessage.window.txt

@@ -6,8 +6,8 @@ Rerun
 
 Found 150 tests
 
-124 Pass
-25 Fail
+133 Pass
+16 Fail
 1 Optional Feature Unsupported
 Details
 Result	Test Name	MessagePass	primitive undefined	
@@ -123,10 +123,10 @@ Fail	Object ImageData object, ImageData 1x1 non-transparent non-black
 Pass	Array sparse	
 Pass	Array with non-index property	
 Pass	Object with index property and length	
-Fail	Array with circular reference	
-Fail	Object with circular reference	
-Fail	Array with identical property values	
-Fail	Object with identical property values	
+Pass	Array with circular reference	
+Pass	Object with circular reference	
+Pass	Array with identical property values	
+Pass	Object with identical property values	
 Pass	Object with property on prototype	
 Pass	Object with non-enumerable property	
 Pass	Object with non-writable property	
@@ -148,14 +148,14 @@ Pass	Length-tracking TypedArray
 Pass	Length-tracking DataView	
 Pass	Serializing OOB TypedArray throws	
 Pass	Serializing OOB DataView throws	
-Fail	ArrayBuffer	
-Fail	MessagePort	
-Fail	A detached ArrayBuffer cannot be transferred	
+Pass	ArrayBuffer	
+Pass	MessagePort	
+Pass	A detached ArrayBuffer cannot be transferred	
 Pass	A detached platform object cannot be transferred	
 Pass	Transferring a non-transferable platform object fails	
-Fail	An object whose interface is deleted from the global object must still be received	
+Pass	An object whose interface is deleted from the global object must still be received	
 Optional Feature Unsupported	A subclass instance will be received as its closest transferable superclass	ReadableStream isn't transferable
-Fail	Resizable ArrayBuffer is transferable	
+Pass	Resizable ArrayBuffer is transferable	
 Fail	Length-tracking TypedArray is transferable	
 Fail	Length-tracking DataView is transferable	
 Pass	Transferring OOB TypedArray throws	

Tests/LibWeb/Text/input/Worker/Worker-postMessage-transfer.html

@@ -24,6 +24,8 @@
         const message = encoder.encode("Hello, world");
         const myBuf = message.buffer;
 
+        println('Buffer length before transfer: ' + myBuf.byteLength);
         worker.postMessage(myBuf, [myBuf]);
+        println('Buffer length after transfer: ' + myBuf.byteLength);
     });
 </script>