Disallow passing a SharedArrayBuffer in the transfer list.

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 92 matching lines @@
   // Array buffer (transferred). transferID:uint32_t
   kArrayBufferTransfer = 't',
   // View into an array buffer.
   // subtag:ArrayBufferViewTag, byteOffset:uint32_t, byteLength:uint32_t
   // For typed arrays, byteOffset and byteLength must be divisible by the size
   // of the element.
   // Note: kArrayBufferView is special, and should have an ArrayBuffer (or an
   // ObjectReference to one) serialized just before it. This is a quirk arising
   // from the previous stack-based implementation.
   kArrayBufferView = 'V',
-  // Shared array buffer (transferred). transferID:uint32_t
-  kSharedArrayBufferTransfer = 'u',
+  // Shared array buffer. transferID:uint32_t
+  kSharedArrayBuffer = 'u',
   // Compiled WebAssembly module. encodingType:(one-byte tag).
   // If encodingType == 'y' (raw bytes):
   //  wasmWireByteLength:uint32_t, then raw data
   //  compiledDataLength:uint32_t, then raw data
   kWasmModule = 'W',
 };
 
 namespace {
 
 enum class ArrayBufferViewTag : uint8_t {
@@ skipping 137 matching lines @@
   auto result = std::make_pair(buffer_, buffer_size_);
   buffer_ = nullptr;
   buffer_size_ = 0;
   buffer_capacity_ = 0;
   return result;
 }
 
 void ValueSerializer::TransferArrayBuffer(uint32_t transfer_id,
                                           Handle<JSArrayBuffer> array_buffer) {
   DCHECK(!array_buffer_transfer_map_.Find(array_buffer));
+  DCHECK(!array_buffer->is_shared());
   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);
   }
 
   DCHECK(object->IsHeapObject());
@@ skipping 153 matching lines @@
     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));
     case JS_SET_TYPE:
       return WriteJSSet(Handle<JSSet>::cast(receiver));
     case JS_ARRAY_BUFFER_TYPE:
-      return WriteJSArrayBuffer(JSArrayBuffer::cast(*receiver));
+      return WriteJSArrayBuffer(Handle<JSArrayBuffer>::cast(receiver));
     case JS_TYPED_ARRAY_TYPE:
     case JS_DATA_VIEW_TYPE:
       return WriteJSArrayBufferView(JSArrayBufferView::cast(*receiver));
     default:
       ThrowDataCloneError(MessageTemplate::kDataCloneError, receiver);
       return Nothing<bool>();
   }
   return Nothing<bool>();
 }
 
@@ skipping 261 matching lines @@
   for (int i = 0; i < length; i++) {
     if (!WriteObject(handle(entries->get(i), isolate_)).FromMaybe(false)) {
       return Nothing<bool>();
     }
   }
   WriteTag(SerializationTag::kEndJSSet);
   WriteVarint<uint32_t>(length);
   return Just(true);
 }
 
-Maybe<bool> ValueSerializer::WriteJSArrayBuffer(JSArrayBuffer* array_buffer) {
-  uint32_t* transfer_entry = array_buffer_transfer_map_.Find(array_buffer);
-  if (transfer_entry) {
-    WriteTag(array_buffer->is_shared()
-                 ? SerializationTag::kSharedArrayBufferTransfer
-                 : SerializationTag::kArrayBufferTransfer);
-    WriteVarint(*transfer_entry);
+Maybe<bool> ValueSerializer::WriteJSArrayBuffer(
+    Handle<JSArrayBuffer> array_buffer) {
+  if (array_buffer->is_shared()) {
+    if (!delegate_) {
+      ThrowDataCloneError(MessageTemplate::kDataCloneError, array_buffer);
+      return Nothing<bool>();
+    }
+
+    v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate_);
+    Maybe<uint32_t> index = delegate_->TransferSharedArrayBuffer(
+        v8_isolate, Utils::ToLocalShared(array_buffer));
+    RETURN_VALUE_IF_SCHEDULED_EXCEPTION(isolate_, Nothing<bool>());
+    DCHECK(!index.IsNothing());

[jbroman, 2016/12/15 16:15:33]

super-nit: index.FromJust() will already crash in this case; is there value
gained by the additional DCHECK?

[binji, 2016/12/15 19:31:20]

Done.

+
+    WriteTag(SerializationTag::kSharedArrayBuffer);
+    WriteVarint(index.FromJust());
     return Just(true);
   }
 
-  if (array_buffer->is_shared()) {
-    ThrowDataCloneError(
-        MessageTemplate::kDataCloneErrorSharedArrayBufferNotTransferred);
-    return Nothing<bool>();
+  uint32_t* transfer_entry = array_buffer_transfer_map_.Find(array_buffer);
+  if (transfer_entry) {
+    WriteTag(SerializationTag::kArrayBufferTransfer);
+    WriteVarint(*transfer_entry);
+    return Just(true);
   }
   if (array_buffer->was_neutered()) {
     ThrowDataCloneError(MessageTemplate::kDataCloneErrorNeuteredArrayBuffer);
     return Nothing<bool>();
   }
   double byte_length = array_buffer->byte_length()->Number();
   if (byte_length > std::numeric_limits<uint32_t>::max()) {
-    ThrowDataCloneError(MessageTemplate::kDataCloneError, handle(array_buffer));
+    ThrowDataCloneError(MessageTemplate::kDataCloneError, array_buffer);
     return Nothing<bool>();
   }
   WriteTag(SerializationTag::kArrayBuffer);
   WriteVarint<uint32_t>(byte_length);
   WriteRawBytes(array_buffer->backing_store(), byte_length);
   return Just(true);
 }
 
 Maybe<bool> ValueSerializer::WriteJSArrayBufferView(JSArrayBufferView* view) {
   WriteTag(SerializationTag::kArrayBufferView);
@@ skipping 339 matching lines @@
     case SerializationTag::kBeginJSMap:
       return ReadJSMap();
     case SerializationTag::kBeginJSSet:
       return ReadJSSet();
     case SerializationTag::kArrayBuffer:
       return ReadJSArrayBuffer();
     case SerializationTag::kArrayBufferTransfer: {
       const bool is_shared = false;
       return ReadTransferredJSArrayBuffer(is_shared);
     }
-    case SerializationTag::kSharedArrayBufferTransfer: {
+    case SerializationTag::kSharedArrayBuffer: {
       const bool is_shared = true;
       return ReadTransferredJSArrayBuffer(is_shared);
     }
     case SerializationTag::kWasmModule:
       return ReadWasmModule();
     default:
       // 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();
@@ skipping 741 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