Support delegating serialization of host objects.

src/value-serializer.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/value-serializer.h"
 
 #include <type_traits>
 
 #include "src/base/logging.h"
 #include "src/conversions.h"
@@ skipping 187 matching lines @@
   buffer_.insert(buffer_.end(), begin, begin + length);
 }
 
 uint8_t* ValueSerializer::ReserveRawBytes(size_t bytes) {
   if (!bytes) return nullptr;
   auto old_size = buffer_.size();
   buffer_.resize(buffer_.size() + bytes);
   return &buffer_[old_size];
 }
 
+void ValueSerializer::WriteUint32(uint32_t value) {
+  WriteVarint<uint32_t>(value);
+}
+
+void ValueSerializer::WriteUint64(uint64_t value) {
+  WriteVarint<uint64_t>(value);
+}
+
 void ValueSerializer::TransferArrayBuffer(uint32_t transfer_id,
                                           Handle<JSArrayBuffer> array_buffer) {
   DCHECK(!array_buffer_transfer_map_.Find(array_buffer));
   array_buffer_transfer_map_.Set(array_buffer, transfer_id);
 }
 
 Maybe<bool> ValueSerializer::WriteObject(Handle<Object> object) {
   if (object->IsSmi()) {
     WriteSmi(Smi::cast(*object));
     return Just(true);
@@ skipping 127 matching lines @@
   }
 
   // If we are at the end of the stack, abort. This function may recurse.
   STACK_CHECK(isolate_, Nothing<bool>());
 
   HandleScope scope(isolate_);
   switch (instance_type) {
     case JS_ARRAY_TYPE:
       return WriteJSArray(Handle<JSArray>::cast(receiver));
     case JS_OBJECT_TYPE:
-    case JS_API_OBJECT_TYPE:
-      return WriteJSObject(Handle<JSObject>::cast(receiver));
+    case JS_API_OBJECT_TYPE: {
+      Handle<JSObject> js_object = Handle<JSObject>::cast(receiver);
+      return js_object->GetInternalFieldCount() ? WriteHostObject(js_object)
+                                                : WriteJSObject(js_object);
+    }
     case JS_DATE_TYPE:
       WriteJSDate(JSDate::cast(*receiver));
       return Just(true);
     case JS_VALUE_TYPE:
       return WriteJSValue(Handle<JSValue>::cast(receiver));
     case JS_REGEXP_TYPE:
       WriteJSRegExp(JSRegExp::cast(*receiver));
       return Just(true);
     case JS_MAP_TYPE:
       return WriteJSMap(Handle<JSMap>::cast(receiver));
@@ skipping 326 matching lines @@
   } else {
     DCHECK(view->IsJSDataView());
     tag = ArrayBufferViewTag::kDataView;
   }
   WriteVarint(static_cast<uint8_t>(tag));
   WriteVarint(NumberToUint32(view->byte_offset()));
   WriteVarint(NumberToUint32(view->byte_length()));
   return Just(true);
 }
 
+Maybe<bool> ValueSerializer::WriteHostObject(Handle<JSObject> object) {
+  if (!delegate_) {
+    isolate_->Throw(*isolate_->factory()->NewError(
+        isolate_->error_function(), MessageTemplate::kDataCloneError, object));
+    return Nothing<bool>();
+  }
+  Maybe<bool> result = delegate_->WriteHostObject(Utils::ToLocal(object));
+  RETURN_VALUE_IF_SCHEDULED_EXCEPTION(isolate_, Nothing<bool>());
+  DCHECK(!result.IsNothing());
+  return result;
+}
+
 Maybe<uint32_t> ValueSerializer::WriteJSObjectPropertiesSlow(
     Handle<JSObject> object, Handle<FixedArray> keys) {
   uint32_t properties_written = 0;
   int length = keys->length();
   for (int i = 0; i < length; i++) {
     Handle<Object> key(keys->get(i), isolate_);
 
     bool success;
     LookupIterator it = LookupIterator::PropertyOrElement(
         isolate_, object, key, &success, LookupIterator::OWN);
@@ skipping 27 matching lines @@
       MessageTemplate::FormatMessage(isolate_, template_index, arg0);
   if (delegate_) {
     delegate_->ThrowDataCloneError(Utils::ToLocal(message));
   } else {
     isolate_->Throw(
         *isolate_->factory()->NewError(isolate_->error_function(), message));
   }
 }
 
 ValueDeserializer::ValueDeserializer(Isolate* isolate,
-                                     Vector<const uint8_t> data)
+                                     Vector<const uint8_t> data,
+                                     v8::ValueDeserializer::Delegate* delegate)
     : isolate_(isolate),
+      delegate_(delegate),
       position_(data.start()),
       end_(data.start() + data.length()),
       id_map_(Handle<SeededNumberDictionary>::cast(
           isolate->global_handles()->Create(
               *SeededNumberDictionary::New(isolate, 0)))) {}
 
 ValueDeserializer::~ValueDeserializer() {
   GlobalHandles::Destroy(Handle<Object>::cast(id_map_).location());
 
   Handle<Object> transfer_map_handle;
@@ skipping 91 matching lines @@
   return Just(value);
 }
 
 Maybe<Vector<const uint8_t>> ValueDeserializer::ReadRawBytes(int size) {
   if (size > end_ - position_) return Nothing<Vector<const uint8_t>>();
   const uint8_t* start = position_;
   position_ += size;
   return Just(Vector<const uint8_t>(start, size));
 }
 
+bool ValueDeserializer::ReadUint32(uint32_t* value) {
+  return ReadVarint<uint32_t>().To(value);
+}
+
+bool ValueDeserializer::ReadUint64(uint64_t* value) {
+  return ReadVarint<uint64_t>().To(value);
+}
+
+bool ValueDeserializer::ReadRawBytes(size_t length, const void** data) {
+  if (length > static_cast<size_t>(end_ - position_)) return false;
+  *data = position_;
+  position_ += length;
+  return true;
+}
+
 void ValueDeserializer::TransferArrayBuffer(
     uint32_t transfer_id, Handle<JSArrayBuffer> array_buffer) {
   if (array_buffer_transfer_map_.is_null()) {
     array_buffer_transfer_map_ =
         Handle<SeededNumberDictionary>::cast(isolate_->global_handles()->Create(
             *SeededNumberDictionary::New(isolate_, 0)));
   }
   Handle<SeededNumberDictionary> dictionary =
       array_buffer_transfer_map_.ToHandleChecked();
   const bool used_as_prototype = false;
@@ skipping 91 matching lines @@
       return ReadJSArrayBuffer();
     case SerializationTag::kArrayBufferTransfer: {
       const bool is_shared = false;
       return ReadTransferredJSArrayBuffer(is_shared);
     }
     case SerializationTag::kSharedArrayBufferTransfer: {
       const bool is_shared = true;
       return ReadTransferredJSArrayBuffer(is_shared);
     }
     default:
-      return MaybeHandle<Object>();
+      // TODO(jbroman): Introduce an explicit tag for host objects to avoid
+      // having to treat every unknown tag as a potential host object.
+      position_--;
+      return ReadHostObject();
   }
 }
 
 MaybeHandle<String> ValueDeserializer::ReadUtf8String() {
   uint32_t utf8_length;
   Vector<const uint8_t> utf8_bytes;
   if (!ReadVarint<uint32_t>().To(&utf8_length) ||
       utf8_length >
           static_cast<uint32_t>(std::numeric_limits<int32_t>::max()) ||
       !ReadRawBytes(utf8_length).To(&utf8_bytes))
@@ skipping 324 matching lines @@
   }
   if (byte_offset % element_size != 0 || byte_length % element_size != 0) {
     return MaybeHandle<JSArrayBufferView>();
   }
   Handle<JSTypedArray> typed_array = isolate_->factory()->NewJSTypedArray(
       external_array_type, buffer, byte_offset, byte_length / element_size);
   AddObjectWithID(id, typed_array);
   return typed_array;
 }
 
+MaybeHandle<JSObject> ValueDeserializer::ReadHostObject() {
+  if (!delegate_) return MaybeHandle<JSObject>();
+  STACK_CHECK(isolate_, MaybeHandle<JSObject>());
+  uint32_t id = next_id_++;
+  v8::Local<v8::Object> object;
+  if (!delegate_->ReadHostObject().ToLocal(&object)) {
+    RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate_, JSObject);
+    return MaybeHandle<JSObject>();
+  }
+  Handle<JSObject> js_object =
+      Handle<JSObject>::cast(Utils::OpenHandle(*object));
+  AddObjectWithID(id, js_object);
+  return js_object;
+}
+
 Maybe<uint32_t> ValueDeserializer::ReadJSObjectProperties(
     Handle<JSObject> object, SerializationTag end_tag) {
   for (uint32_t num_properties = 0;; num_properties++) {
     SerializationTag tag;
     if (!PeekTag().To(&tag)) return Nothing<uint32_t>();
     if (tag == end_tag) {
       ConsumeTag(end_tag);
       return Just(num_properties);
     }
 
@@ skipping 150 matching lines @@
   if (stack.size() != 1) {
     isolate_->Throw(*isolate_->factory()->NewError(
         MessageTemplate::kDataCloneDeserializationError));
     return MaybeHandle<Object>();
   }
   return scope.CloseAndEscape(stack[0]);
 }
 
 }  // namespace internal
 }  // namespace v8