Revert of [d8] Use ValueSerializer for postMessage (instead of ad-hoc serializer)

src/d8.cc

Index: src/d8.cc
diff --git a/src/d8.cc b/src/d8.cc
index 13f0bc1ff05de8271ab8f1ccd9ed6df644108429..171c59b6f0464fb9dc314cb8a2d9246aa6574f70 100644
--- a/src/d8.cc
+++ b/src/d8.cc
@@ -31,7 +31,6 @@
 #include "src/base/sys-info.h"
 #include "src/basic-block-profiler.h"
 #include "src/interpreter/interpreter.h"
-#include "src/list-inl.h"
 #include "src/msan.h"
 #include "src/objects-inl.h"
 #include "src/snapshot/natives.h"
@@ -219,6 +218,16 @@
 }
 
 
+bool FindInObjectList(Local<Object> object, const Shell::ObjectList& list) {
+  for (int i = 0; i < list.length(); ++i) {
+    if (list[i]->StrictEquals(object)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+
 Worker* GetWorkerFromInternalField(Isolate* isolate, Local<Object> object) {
   if (object->InternalFieldCount() != 1) {
     Throw(isolate, "this is not a Worker");
@@ -401,10 +410,7 @@
 base::LazyMutex Shell::workers_mutex_;
 bool Shell::allow_new_workers_ = true;
 i::List<Worker*> Shell::workers_;
-std::unordered_set<SharedArrayBuffer::Contents,
-                   Shell::SharedArrayBufferContentsHash,
-                   Shell::SharedArrayBufferContentsIsEqual>
-    Shell::externalized_shared_contents_;
+i::List<SharedArrayBuffer::Contents> Shell::externalized_shared_contents_;
 
 Global<Context> Shell::evaluation_context_;
 ArrayBuffer::Allocator* Shell::array_buffer_allocator;
@@ -1144,6 +1150,7 @@
 void Shell::WorkerPostMessage(const v8::FunctionCallbackInfo<v8::Value>& args) {
   Isolate* isolate = args.GetIsolate();
   HandleScope handle_scope(isolate);
+  Local<Context> context = isolate->GetCurrentContext();
 
   if (args.Length() < 1) {
     Throw(isolate, "Invalid argument");
@@ -1156,12 +1163,36 @@
   }
 
   Local<Value> message = args[0];
-  Local<Value> transfer =
-      args.Length() >= 2 ? args[1] : Local<Value>::Cast(Undefined(isolate));
-  std::unique_ptr<SerializationData> data =
-      Shell::SerializeValue(isolate, message, transfer);
-  if (data) {
-    worker->PostMessage(std::move(data));
+  ObjectList to_transfer;
+  if (args.Length() >= 2) {
+    if (!args[1]->IsArray()) {
+      Throw(isolate, "Transfer list must be an Array");
+      return;
+    }
+
+    Local<Array> transfer = Local<Array>::Cast(args[1]);
+    uint32_t length = transfer->Length();
+    for (uint32_t i = 0; i < length; ++i) {
+      Local<Value> element;
+      if (transfer->Get(context, i).ToLocal(&element)) {
+        if (!element->IsArrayBuffer() && !element->IsSharedArrayBuffer()) {
+          Throw(isolate,
+                "Transfer array elements must be an ArrayBuffer or "
+                "SharedArrayBuffer.");
+          break;
+        }
+
+        to_transfer.Add(Local<Object>::Cast(element));
+      }
+    }
+  }
+
+  ObjectList seen_objects;
+  SerializationData* data = new SerializationData;
+  if (SerializeValue(isolate, message, to_transfer, &seen_objects, data)) {
+    worker->PostMessage(data);
+  } else {
+    delete data;
   }
 }
 
@@ -1174,12 +1205,14 @@
     return;
   }
 
-  std::unique_ptr<SerializationData> data = worker->GetMessage();
+  SerializationData* data = worker->GetMessage();
   if (data) {
-    Local<Value> value;
-    if (Shell::DeserializeValue(isolate, std::move(data)).ToLocal(&value)) {
-      args.GetReturnValue().Set(value);
-    }
+    int offset = 0;
+    Local<Value> data_value;
+    if (Shell::DeserializeValue(isolate, *data, &offset).ToLocal(&data_value)) {
+      args.GetReturnValue().Set(data_value);
+    }
+    delete data;
   }
 }
 
@@ -2115,12 +2148,14 @@
   thread_->Join();
 }
 
+
 SerializationData::~SerializationData() {
   // Any ArrayBuffer::Contents are owned by this SerializationData object if
-  // ownership hasn't been transferred out.
+  // ownership hasn't been transferred out via ReadArrayBufferContents.
   // SharedArrayBuffer::Contents may be used by multiple threads, so must be
   // cleaned up by the main thread in Shell::CleanupWorkers().
-  for (const auto& contents : array_buffer_contents_) {
+  for (int i = 0; i < array_buffer_contents_.length(); ++i) {
+    ArrayBuffer::Contents& contents = array_buffer_contents_[i];
     if (contents.Data()) {
       Shell::array_buffer_allocator->Free(contents.Data(),
                                           contents.ByteLength());
@@ -2128,35 +2163,96 @@
   }
 }
 
-void SerializationData::ClearTransferredArrayBuffers() {
-  array_buffer_contents_.clear();
-}
-
-void SerializationDataQueue::Enqueue(std::unique_ptr<SerializationData> data) {
+
+void SerializationData::WriteTag(SerializationTag tag) { data_.Add(tag); }
+
+
+void SerializationData::WriteMemory(const void* p, int length) {
+  if (length > 0) {
+    i::Vector<uint8_t> block = data_.AddBlock(0, length);
+    memcpy(&block[0], p, length);
+  }
+}
+
+
+void SerializationData::WriteArrayBufferContents(
+    const ArrayBuffer::Contents& contents) {
+  array_buffer_contents_.Add(contents);
+  WriteTag(kSerializationTagTransferredArrayBuffer);
+  int index = array_buffer_contents_.length() - 1;
+  Write(index);
+}
+
+
+void SerializationData::WriteSharedArrayBufferContents(
+    const SharedArrayBuffer::Contents& contents) {
+  shared_array_buffer_contents_.Add(contents);
+  WriteTag(kSerializationTagTransferredSharedArrayBuffer);
+  int index = shared_array_buffer_contents_.length() - 1;
+  Write(index);
+}
+
+
+SerializationTag SerializationData::ReadTag(int* offset) const {
+  return static_cast<SerializationTag>(Read<uint8_t>(offset));
+}
+
+
+void SerializationData::ReadMemory(void* p, int length, int* offset) const {
+  if (length > 0) {
+    memcpy(p, &data_[*offset], length);
+    (*offset) += length;
+  }
+}
+
+
+void SerializationData::ReadArrayBufferContents(ArrayBuffer::Contents* contents,
+                                                int* offset) const {
+  int index = Read<int>(offset);
+  DCHECK(index < array_buffer_contents_.length());
+  *contents = array_buffer_contents_[index];
+  // Ownership of this ArrayBuffer::Contents is passed to the caller. Neuter
+  // our copy so it won't be double-free'd when this SerializationData is
+  // destroyed.
+  array_buffer_contents_[index] = ArrayBuffer::Contents();
+}
+
+
+void SerializationData::ReadSharedArrayBufferContents(
+    SharedArrayBuffer::Contents* contents, int* offset) const {
+  int index = Read<int>(offset);
+  DCHECK(index < shared_array_buffer_contents_.length());
+  *contents = shared_array_buffer_contents_[index];
+}
+
+
+void SerializationDataQueue::Enqueue(SerializationData* data) {
   base::LockGuard<base::Mutex> lock_guard(&mutex_);
-  data_.push_back(std::move(data));
-}
-
-bool SerializationDataQueue::Dequeue(
-    std::unique_ptr<SerializationData>* out_data) {
-  out_data->reset();
+  data_.Add(data);
+}
+
+
+bool SerializationDataQueue::Dequeue(SerializationData** data) {
   base::LockGuard<base::Mutex> lock_guard(&mutex_);
-  if (data_.empty()) return false;
-  *out_data = std::move(data_[0]);
-  data_.erase(data_.begin());
+  *data = NULL;
+  if (data_.is_empty()) return false;
+  *data = data_.Remove(0);
   return true;
 }
 
 
 bool SerializationDataQueue::IsEmpty() {
   base::LockGuard<base::Mutex> lock_guard(&mutex_);
-  return data_.empty();
+  return data_.is_empty();
 }
 
 
 void SerializationDataQueue::Clear() {
   base::LockGuard<base::Mutex> lock_guard(&mutex_);
-  data_.clear();
+  for (int i = 0; i < data_.length(); ++i) {
+    delete data_[i];
+  }
+  data_.Clear();
 }
 
 
@@ -2185,20 +2281,22 @@
   thread_->Start();
 }
 
-void Worker::PostMessage(std::unique_ptr<SerializationData> data) {
-  in_queue_.Enqueue(std::move(data));
+
+void Worker::PostMessage(SerializationData* data) {
+  in_queue_.Enqueue(data);
   in_semaphore_.Signal();
 }
 
-std::unique_ptr<SerializationData> Worker::GetMessage() {
-  std::unique_ptr<SerializationData> result;
-  while (!out_queue_.Dequeue(&result)) {
+
+SerializationData* Worker::GetMessage() {
+  SerializationData* data = NULL;
+  while (!out_queue_.Dequeue(&data)) {
     // If the worker is no longer running, and there are no messages in the
     // queue, don't expect any more messages from it.
     if (!base::NoBarrier_Load(&running_)) break;
     out_semaphore_.Wait();
   }
-  return result;
+  return data;
 }
 
 
@@ -2262,21 +2360,19 @@
             // Now wait for messages
             while (true) {
               in_semaphore_.Wait();
-              std::unique_ptr<SerializationData> data;
+              SerializationData* data;
               if (!in_queue_.Dequeue(&data)) continue;
-              if (!data) {
+              if (data == NULL) {
                 break;
               }
-              v8::TryCatch try_catch(isolate);
-              Local<Value> value;
-              if (Shell::DeserializeValue(isolate, std::move(data))
-                      .ToLocal(&value)) {
-                Local<Value> argv[] = {value};
+              int offset = 0;
+              Local<Value> data_value;
+              if (Shell::DeserializeValue(isolate, *data, &offset)
+                      .ToLocal(&data_value)) {
+                Local<Value> argv[] = {data_value};
                 (void)onmessage_fun->Call(context, global, 1, argv);
               }
-              if (try_catch.HasCaught()) {
-                Shell::ReportException(isolate, &try_catch);
-              }
+              delete data;
             }
           }
         }
@@ -2303,15 +2399,21 @@
   }
 
   Local<Value> message = args[0];
-  Local<Value> transfer = Undefined(isolate);
-  std::unique_ptr<SerializationData> data =
-      Shell::SerializeValue(isolate, message, transfer);
-  if (data) {
+
+  // TODO(binji): Allow transferring from worker to main thread?
+  Shell::ObjectList to_transfer;
+
+  Shell::ObjectList seen_objects;
+  SerializationData* data = new SerializationData;
+  if (Shell::SerializeValue(isolate, message, to_transfer, &seen_objects,
+                            data)) {
     DCHECK(args.Data()->IsExternal());
     Local<External> this_value = Local<External>::Cast(args.Data());
     Worker* worker = static_cast<Worker*>(this_value->Value());
-    worker->out_queue_.Enqueue(std::move(data));
+    worker->out_queue_.Enqueue(data);
     worker->out_semaphore_.Signal();
+  } else {
+    delete data;
   }
 }
 
@@ -2504,202 +2606,234 @@
   }
 }
 
-class Serializer : public ValueSerializer::Delegate {
- public:
-  explicit Serializer(Isolate* isolate)
-      : isolate_(isolate), serializer_(isolate, this) {}
-
-  Maybe<bool> WriteValue(Local<Context> context, Local<Value> value,
-                         Local<Value> transfer) {
-    bool ok;
-    DCHECK(!data_);
-    data_.reset(new SerializationData);
-    if (!PrepareTransfer(context, transfer).To(&ok)) {
-      return Nothing<bool>();
-    }
-    serializer_.WriteHeader();
-
-    if (!serializer_.WriteValue(context, value).To(&ok)) {
-      data_.reset();
-      return Nothing<bool>();
-    }
-
-    if (!FinalizeTransfer().To(&ok)) {
-      return Nothing<bool>();
-    }
-
-    std::pair<uint8_t*, size_t> pair = serializer_.Release();
-    data_->data_.reset(pair.first);
-    data_->size_ = pair.second;
-    return Just(true);
-  }
-
-  std::unique_ptr<SerializationData> Release() { return std::move(data_); }
-
- protected:
-  // Implements ValueSerializer::Delegate.
-  void ThrowDataCloneError(Local<String> message) override {
-    isolate_->ThrowException(Exception::Error(message));
-  }
-
-  Maybe<uint32_t> GetSharedArrayBufferId(
-      Isolate* isolate, Local<SharedArrayBuffer> shared_array_buffer) override {
-    DCHECK(data_ != nullptr);
-    for (size_t index = 0; index < shared_array_buffers_.size(); ++index) {
-      if (shared_array_buffers_[index] == shared_array_buffer) {
-        return Just<uint32_t>(static_cast<uint32_t>(index));
+
+bool Shell::SerializeValue(Isolate* isolate, Local<Value> value,
+                           const ObjectList& to_transfer,
+                           ObjectList* seen_objects,
+                           SerializationData* out_data) {
+  DCHECK(out_data);
+  Local<Context> context = isolate->GetCurrentContext();
+
+  if (value->IsUndefined()) {
+    out_data->WriteTag(kSerializationTagUndefined);
+  } else if (value->IsNull()) {
+    out_data->WriteTag(kSerializationTagNull);
+  } else if (value->IsTrue()) {
+    out_data->WriteTag(kSerializationTagTrue);
+  } else if (value->IsFalse()) {
+    out_data->WriteTag(kSerializationTagFalse);
+  } else if (value->IsNumber()) {
+    Local<Number> num = Local<Number>::Cast(value);
+    double value = num->Value();
+    out_data->WriteTag(kSerializationTagNumber);
+    out_data->Write(value);
+  } else if (value->IsString()) {
+    v8::String::Utf8Value str(value);
+    out_data->WriteTag(kSerializationTagString);
+    out_data->Write(str.length());
+    out_data->WriteMemory(*str, str.length());
+  } else if (value->IsArray()) {
+    Local<Array> array = Local<Array>::Cast(value);
+    if (FindInObjectList(array, *seen_objects)) {
+      Throw(isolate, "Duplicated arrays not supported");
+      return false;
+    }
+    seen_objects->Add(array);
+    out_data->WriteTag(kSerializationTagArray);
+    uint32_t length = array->Length();
+    out_data->Write(length);
+    for (uint32_t i = 0; i < length; ++i) {
+      Local<Value> element_value;
+      if (array->Get(context, i).ToLocal(&element_value)) {
+        if (!SerializeValue(isolate, element_value, to_transfer, seen_objects,
+                            out_data))
+          return false;
+      } else {
+        Throw(isolate, "Failed to serialize array element.");
+        return false;
       }
     }
-
-    size_t index = shared_array_buffers_.size();
-    shared_array_buffers_.emplace_back(isolate_, shared_array_buffer);
-    return Just<uint32_t>(static_cast<uint32_t>(index));
-  }
-
-  void* ReallocateBufferMemory(void* old_buffer, size_t size,
-                               size_t* actual_size) override {
-    void* result = realloc(old_buffer, size);
-    *actual_size = result ? size : 0;
-    return result;
-  }
-
-  void FreeBufferMemory(void* buffer) override { free(buffer); }
-
- private:
-  Maybe<bool> PrepareTransfer(Local<Context> context, Local<Value> transfer) {
-    if (transfer->IsArray()) {
-      Local<Array> transfer_array = Local<Array>::Cast(transfer);
-      uint32_t length = transfer_array->Length();
+  } else if (value->IsArrayBuffer()) {
+    Local<ArrayBuffer> array_buffer = Local<ArrayBuffer>::Cast(value);
+    if (FindInObjectList(array_buffer, *seen_objects)) {
+      Throw(isolate, "Duplicated array buffers not supported");
+      return false;
+    }
+    seen_objects->Add(array_buffer);
+    if (FindInObjectList(array_buffer, to_transfer)) {
+      // Transfer ArrayBuffer
+      if (!array_buffer->IsNeuterable()) {
+        Throw(isolate, "Attempting to transfer an un-neuterable ArrayBuffer");
+        return false;
+      }
+
+      ArrayBuffer::Contents contents = array_buffer->IsExternal()
+                                           ? array_buffer->GetContents()
+                                           : array_buffer->Externalize();
+      array_buffer->Neuter();
+      out_data->WriteArrayBufferContents(contents);
+    } else {
+      ArrayBuffer::Contents contents = array_buffer->GetContents();
+      // Clone ArrayBuffer
+      if (contents.ByteLength() > i::kMaxInt) {
+        Throw(isolate, "ArrayBuffer is too big to clone");
+        return false;
+      }
+
+      int32_t byte_length = static_cast<int32_t>(contents.ByteLength());
+      out_data->WriteTag(kSerializationTagArrayBuffer);
+      out_data->Write(byte_length);
+      out_data->WriteMemory(contents.Data(), byte_length);
+    }
+  } else if (value->IsSharedArrayBuffer()) {
+    Local<SharedArrayBuffer> sab = Local<SharedArrayBuffer>::Cast(value);
+    if (FindInObjectList(sab, *seen_objects)) {
+      Throw(isolate, "Duplicated shared array buffers not supported");
+      return false;
+    }
+    seen_objects->Add(sab);
+    if (!FindInObjectList(sab, to_transfer)) {
+      Throw(isolate, "SharedArrayBuffer must be transferred");
+      return false;
+    }
+
+    SharedArrayBuffer::Contents contents;
+    if (sab->IsExternal()) {
+      contents = sab->GetContents();
+    } else {
+      contents = sab->Externalize();
+      base::LockGuard<base::Mutex> lock_guard(workers_mutex_.Pointer());
+      externalized_shared_contents_.Add(contents);
+    }
+    out_data->WriteSharedArrayBufferContents(contents);
+  } else if (value->IsObject()) {
+    Local<Object> object = Local<Object>::Cast(value);
+    if (FindInObjectList(object, *seen_objects)) {
+      Throw(isolate, "Duplicated objects not supported");
+      return false;
+    }
+    seen_objects->Add(object);
+    Local<Array> property_names;
+    if (!object->GetOwnPropertyNames(context).ToLocal(&property_names)) {
+      Throw(isolate, "Unable to get property names");
+      return false;
+    }
+
+    uint32_t length = property_names->Length();
+    out_data->WriteTag(kSerializationTagObject);
+    out_data->Write(length);
+    for (uint32_t i = 0; i < length; ++i) {
+      Local<Value> name;
+      Local<Value> property_value;
+      if (property_names->Get(context, i).ToLocal(&name) &&
+          object->Get(context, name).ToLocal(&property_value)) {
+        if (!SerializeValue(isolate, name, to_transfer, seen_objects, out_data))
+          return false;
+        if (!SerializeValue(isolate, property_value, to_transfer, seen_objects,
+                            out_data))
+          return false;
+      } else {
+        Throw(isolate, "Failed to serialize property.");
+        return false;
+      }
+    }
+  } else {
+    Throw(isolate, "Don't know how to serialize object");
+    return false;
+  }
+
+  return true;
+}
+
+
+MaybeLocal<Value> Shell::DeserializeValue(Isolate* isolate,
+                                          const SerializationData& data,
+                                          int* offset) {
+  DCHECK(offset);
+  EscapableHandleScope scope(isolate);
+  Local<Value> result;
+  SerializationTag tag = data.ReadTag(offset);
+
+  switch (tag) {
+    case kSerializationTagUndefined:
+      result = Undefined(isolate);
+      break;
+    case kSerializationTagNull:
+      result = Null(isolate);
+      break;
+    case kSerializationTagTrue:
+      result = True(isolate);
+      break;
+    case kSerializationTagFalse:
+      result = False(isolate);
+      break;
+    case kSerializationTagNumber:
+      result = Number::New(isolate, data.Read<double>(offset));
+      break;
+    case kSerializationTagString: {
+      int length = data.Read<int>(offset);
+      CHECK(length >= 0);
+      std::vector<char> buffer(length + 1);  // + 1 so it is never empty.
+      data.ReadMemory(&buffer[0], length, offset);
+      MaybeLocal<String> str =
+          String::NewFromUtf8(isolate, &buffer[0], NewStringType::kNormal,
+                              length).ToLocalChecked();
+      if (!str.IsEmpty()) result = str.ToLocalChecked();
+      break;
+    }
+    case kSerializationTagArray: {
+      uint32_t length = data.Read<uint32_t>(offset);
+      Local<Array> array = Array::New(isolate, length);
       for (uint32_t i = 0; i < length; ++i) {
-        Local<Value> element;
-        if (transfer_array->Get(context, i).ToLocal(&element)) {
-          if (!element->IsArrayBuffer()) {
-            Throw(isolate_, "Transfer array elements must be an ArrayBuffer");
-            break;
-          }
-
-          Local<ArrayBuffer> array_buffer = Local<ArrayBuffer>::Cast(element);
-          serializer_.TransferArrayBuffer(
-              static_cast<uint32_t>(array_buffers_.size()), array_buffer);
-          array_buffers_.emplace_back(isolate_, array_buffer);
-        } else {
-          return Nothing<bool>();
-        }
+        Local<Value> element_value;
+        CHECK(DeserializeValue(isolate, data, offset).ToLocal(&element_value));
+        array->Set(isolate->GetCurrentContext(), i, element_value).FromJust();
       }
-      return Just(true);
-    } else if (transfer->IsUndefined()) {
-      return Just(true);
-    } else {
-      Throw(isolate_, "Transfer list must be an Array or undefined");
-      return Nothing<bool>();
-    }
-  }
-
-  Maybe<bool> FinalizeTransfer() {
-    for (const auto& global_array_buffer : array_buffers_) {
-      Local<ArrayBuffer> array_buffer =
-          Local<ArrayBuffer>::New(isolate_, global_array_buffer);
-      if (!array_buffer->IsNeuterable()) {
-        Throw(isolate_, "ArrayBuffer could not be transferred");
-        return Nothing<bool>();
+      result = array;
+      break;
+    }
+    case kSerializationTagObject: {
+      int length = data.Read<int>(offset);
+      Local<Object> object = Object::New(isolate);
+      for (int i = 0; i < length; ++i) {
+        Local<Value> property_name;
+        CHECK(DeserializeValue(isolate, data, offset).ToLocal(&property_name));
+        Local<Value> property_value;
+        CHECK(DeserializeValue(isolate, data, offset).ToLocal(&property_value));
+        object->Set(isolate->GetCurrentContext(), property_name, property_value)
+            .FromJust();
       }
-
-      if (!array_buffer->IsExternal()) {
-        array_buffer->Externalize();
-      }
+      result = object;
+      break;
+    }
+    case kSerializationTagArrayBuffer: {
+      int32_t byte_length = data.Read<int32_t>(offset);
+      Local<ArrayBuffer> array_buffer = ArrayBuffer::New(isolate, byte_length);
       ArrayBuffer::Contents contents = array_buffer->GetContents();
-      array_buffer->Neuter();
-      data_->array_buffer_contents_.push_back(contents);
-    }
-
-    for (const auto& global_shared_array_buffer : shared_array_buffers_) {
-      Local<SharedArrayBuffer> shared_array_buffer =
-          Local<SharedArrayBuffer>::New(isolate_, global_shared_array_buffer);
-      if (!shared_array_buffer->IsExternal()) {
-        shared_array_buffer->Externalize();
-      }
-      data_->shared_array_buffer_contents_.push_back(
-          shared_array_buffer->GetContents());
-    }
-
-    return Just(true);
-  }
-
-  Isolate* isolate_;
-  ValueSerializer serializer_;
-  std::unique_ptr<SerializationData> data_;
-  std::vector<Global<ArrayBuffer>> array_buffers_;
-  std::vector<Global<SharedArrayBuffer>> shared_array_buffers_;
-
-  DISALLOW_COPY_AND_ASSIGN(Serializer);
-};
-
-class Deserializer : public ValueDeserializer::Delegate {
- public:
-  Deserializer(Isolate* isolate, std::unique_ptr<SerializationData> data)
-      : isolate_(isolate),
-        deserializer_(isolate, data->data(), data->size(), this),
-        data_(std::move(data)) {
-    deserializer_.SetSupportsLegacyWireFormat(true);
-  }
-
-  MaybeLocal<Value> ReadValue(Local<Context> context) {
-    bool read_header;
-    if (!deserializer_.ReadHeader(context).To(&read_header)) {
-      return MaybeLocal<Value>();
-    }
-
-    uint32_t index = 0;
-    for (const auto& contents : data_->array_buffer_contents()) {
-      Local<ArrayBuffer> array_buffer =
-          ArrayBuffer::New(isolate_, contents.Data(), contents.ByteLength());
-      deserializer_.TransferArrayBuffer(index++, array_buffer);
-    }
-
-    index = 0;
-    for (const auto& contents : data_->shared_array_buffer_contents()) {
-      Local<SharedArrayBuffer> shared_array_buffer = SharedArrayBuffer::New(
-          isolate_, contents.Data(), contents.ByteLength());
-      deserializer_.TransferSharedArrayBuffer(index++, shared_array_buffer);
-    }
-
-    MaybeLocal<Value> result = deserializer_.ReadValue(context);
-    if (!result.IsEmpty()) {
-      data_->ClearTransferredArrayBuffers();
-    }
-    return result;
-  }
-
- private:
-  Isolate* isolate_;
-  ValueDeserializer deserializer_;
-  std::unique_ptr<SerializationData> data_;
-
-  DISALLOW_COPY_AND_ASSIGN(Deserializer);
-};
-
-std::unique_ptr<SerializationData> Shell::SerializeValue(
-    Isolate* isolate, Local<Value> value, Local<Value> transfer) {
-  bool ok;
-  Local<Context> context = isolate->GetCurrentContext();
-  Serializer serializer(isolate);
-  if (serializer.WriteValue(context, value, transfer).To(&ok)) {
-    std::unique_ptr<SerializationData> data = serializer.Release();
-    base::LockGuard<base::Mutex> lock_guard(workers_mutex_.Pointer());
-    for (const auto& contents : data->shared_array_buffer_contents()) {
-      externalized_shared_contents_.insert(contents);
-    }
-    return data;
-  }
-  return nullptr;
-}
-
-MaybeLocal<Value> Shell::DeserializeValue(
-    Isolate* isolate, std::unique_ptr<SerializationData> data) {
-  Local<Value> value;
-  Local<Context> context = isolate->GetCurrentContext();
-  Deserializer deserializer(isolate, std::move(data));
-  return deserializer.ReadValue(context);
+      DCHECK(static_cast<size_t>(byte_length) == contents.ByteLength());
+      data.ReadMemory(contents.Data(), byte_length, offset);
+      result = array_buffer;
+      break;
+    }
+    case kSerializationTagTransferredArrayBuffer: {
+      ArrayBuffer::Contents contents;
+      data.ReadArrayBufferContents(&contents, offset);
+      result = ArrayBuffer::New(isolate, contents.Data(), contents.ByteLength(),
+                                ArrayBufferCreationMode::kInternalized);
+      break;
+    }
+    case kSerializationTagTransferredSharedArrayBuffer: {
+      SharedArrayBuffer::Contents contents;
+      data.ReadSharedArrayBufferContents(&contents, offset);
+      result = SharedArrayBuffer::New(isolate, contents.Data(),
+                                      contents.ByteLength());
+      break;
+    }
+    default:
+      UNREACHABLE();
+  }
+
+  return scope.Escape(result);
 }
 
 
@@ -2725,10 +2859,12 @@
   base::LockGuard<base::Mutex> lock_guard(workers_mutex_.Pointer());
   allow_new_workers_ = true;
 
-  for (const auto& contents : externalized_shared_contents_) {
+  for (int i = 0; i < externalized_shared_contents_.length(); ++i) {
+    const SharedArrayBuffer::Contents& contents =
+        externalized_shared_contents_[i];
     Shell::array_buffer_allocator->Free(contents.Data(), contents.ByteLength());
   }
-  externalized_shared_contents_.clear();
+  externalized_shared_contents_.Clear();
 }