Disallow passing a SharedArrayBuffer in the transfer list.

src/value-serializer.cc

Index: src/value-serializer.cc
diff --git a/src/value-serializer.cc b/src/value-serializer.cc
index 81301fd55395b4e8d2f356ec9413da6b6425953b..b19dfe887b66f610193f1042bad86aae73bf974b 100644
--- a/src/value-serializer.cc
+++ b/src/value-serializer.cc
@@ -110,8 +110,8 @@ enum class SerializationTag : uint8_t {
   // 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
@@ -269,6 +269,7 @@ std::pair<uint8_t*, size_t> ValueSerializer::Release() {
 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);
 }
 
@@ -442,7 +443,7 @@ Maybe<bool> ValueSerializer::WriteJSReceiver(Handle<JSReceiver> 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));
@@ -724,28 +725,38 @@ Maybe<bool> ValueSerializer::WriteJSSet(Handle<JSSet> set) {
   return Just(true);
 }
 
-Maybe<bool> ValueSerializer::WriteJSArrayBuffer(JSArrayBuffer* array_buffer) {
+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);
+  }
+
   uint32_t* transfer_entry = array_buffer_transfer_map_.Find(array_buffer);
   if (transfer_entry) {
-    WriteTag(array_buffer->is_shared()
-                 ? SerializationTag::kSharedArrayBufferTransfer
-                 : SerializationTag::kArrayBufferTransfer);
+    WriteTag(SerializationTag::kArrayBufferTransfer);
     WriteVarint(*transfer_entry);
     return Just(true);
   }
-
-  if (array_buffer->is_shared()) {
-    ThrowDataCloneError(
-        MessageTemplate::kDataCloneErrorSharedArrayBufferNotTransferred);
-    return Nothing<bool>();
-  }
   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);
@@ -1105,7 +1116,7 @@ MaybeHandle<Object> ValueDeserializer::ReadObjectInternal() {
       const bool is_shared = false;
       return ReadTransferredJSArrayBuffer(is_shared);
     }
-    case SerializationTag::kSharedArrayBufferTransfer: {
+    case SerializationTag::kSharedArrayBuffer: {
       const bool is_shared = true;
       return ReadTransferredJSArrayBuffer(is_shared);
     }