Blink-compatible serialization of ArrayBuffer transfer.

src/value-serializer.h

 // 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.
 
 #ifndef V8_VALUE_SERIALIZER_H_
 #define V8_VALUE_SERIALIZER_H_
 
 #include <cstdint>
 #include <vector>
 
@@ skipping 41 matching lines @@
    * Serializes a V8 object into the buffer.
    */
   Maybe<bool> WriteObject(Handle<Object> object) WARN_UNUSED_RESULT;
 
   /*
    * Returns the stored data. This serializer should not be used once the buffer
    * is released. The contents are undefined if a previous write has failed.
    */
   std::vector<uint8_t> ReleaseBuffer() { return std::move(buffer_); }
 
+  /*
+   * Marks an ArrayBuffer as havings its contents transferred out of band.
+   * Pass the corresponding JSArrayBuffer in the deserializing context to
+   * ValueDeserializer::TransferArrayBuffer.
+   */
+  void TransferArrayBuffer(uint32_t transfer_id,
+                           Handle<JSArrayBuffer> array_buffer);
+
  private:
   // Writing the wire format.
   void WriteTag(SerializationTag tag);
   template <typename T>
   void WriteVarint(T value);
   template <typename T>
   void WriteZigZag(T value);
   void WriteDouble(double value);
   void WriteOneByteString(Vector<const uint8_t> chars);
   void WriteTwoByteString(Vector<const uc16> chars);
@@ skipping 26 matching lines @@
   Isolate* const isolate_;
   std::vector<uint8_t> buffer_;
   Zone zone_;
 
   // To avoid extra lookups in the identity map, ID+1 is actually stored in the
   // map (checking if the used identity is zero is the fast way of checking if
   // the entry is new).
   IdentityMap<uint32_t> id_map_;
   uint32_t next_id_ = 0;
 
+  // A similar map, for transferred array buffers.
+  IdentityMap<uint32_t> array_buffer_transfer_map_;
+
   DISALLOW_COPY_AND_ASSIGN(ValueSerializer);
 };
 
 /*
  * Deserializes values from data written with ValueSerializer, or a compatible
  * implementation.
  */
 class ValueDeserializer {
  public:
   ValueDeserializer(Isolate* isolate, Vector<const uint8_t> data);
@@ skipping 19 matching lines @@
   /*
    * Reads an object, consuming the entire buffer.
    *
    * This is required for the legacy "version 0" format, which did not allow
    * reference deduplication, and instead relied on a "stack" model for
    * deserializing, with the contents of objects and arrays provided first.
    */
   MaybeHandle<Object> ReadObjectUsingEntireBufferForLegacyFormat()
       WARN_UNUSED_RESULT;
 
+  /*
+   * Accepts the array buffer corresponding to the one passed previously to
+   * ValueSerializer::TransferArrayBuffer.
+   */
+  void TransferArrayBuffer(uint32_t transfer_id,
+                           Handle<JSArrayBuffer> array_buffer);
+
  private:
   // Reading the wire format.
   Maybe<SerializationTag> PeekTag() const WARN_UNUSED_RESULT;
   void ConsumeTag(SerializationTag peeked_tag);
   Maybe<SerializationTag> ReadTag() WARN_UNUSED_RESULT;
   template <typename T>
   Maybe<T> ReadVarint() WARN_UNUSED_RESULT;
   template <typename T>
   Maybe<T> ReadZigZag() WARN_UNUSED_RESULT;
   Maybe<double> ReadDouble() WARN_UNUSED_RESULT;
   Maybe<Vector<const uint8_t>> ReadRawBytes(int size) WARN_UNUSED_RESULT;
 
   // Reading V8 objects of specific kinds.
   // The tag is assumed to have already been read.
   MaybeHandle<String> ReadUtf8String() WARN_UNUSED_RESULT;
   MaybeHandle<String> ReadTwoByteString() WARN_UNUSED_RESULT;
   MaybeHandle<JSObject> ReadJSObject() WARN_UNUSED_RESULT;
   MaybeHandle<JSArray> ReadSparseJSArray() WARN_UNUSED_RESULT;
   MaybeHandle<JSArray> ReadDenseJSArray() WARN_UNUSED_RESULT;
   MaybeHandle<JSDate> ReadJSDate() WARN_UNUSED_RESULT;
   MaybeHandle<JSValue> ReadJSValue(SerializationTag tag) WARN_UNUSED_RESULT;
   MaybeHandle<JSRegExp> ReadJSRegExp() WARN_UNUSED_RESULT;
   MaybeHandle<JSMap> ReadJSMap() WARN_UNUSED_RESULT;
   MaybeHandle<JSSet> ReadJSSet() WARN_UNUSED_RESULT;
   MaybeHandle<JSArrayBuffer> ReadJSArrayBuffer() WARN_UNUSED_RESULT;
+  MaybeHandle<JSArrayBuffer> ReadTransferredJSArrayBuffer() WARN_UNUSED_RESULT;
 
   /*
    * Reads key-value pairs into the object until the specified end tag is
    * encountered. If successful, returns the number of properties read.
    */
   Maybe<uint32_t> ReadJSObjectProperties(Handle<JSObject> object,
                                          SerializationTag end_tag);
 
   // Manipulating the map from IDs to reified objects.
   bool HasObjectWithID(uint32_t id);
   MaybeHandle<JSReceiver> GetObjectWithID(uint32_t id);
   void AddObjectWithID(uint32_t id, Handle<JSReceiver> object);
 
   Isolate* const isolate_;
   const uint8_t* position_;
   const uint8_t* const end_;
   uint32_t version_ = 0;
-  Handle<SeededNumberDictionary> id_map_;  // Always a global handle.
   uint32_t next_id_ = 0;
 
+  // Always global handles.
+  Handle<SeededNumberDictionary> id_map_;
+  MaybeHandle<SeededNumberDictionary> array_buffer_transfer_map_;
+
   DISALLOW_COPY_AND_ASSIGN(ValueDeserializer);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_VALUE_SERIALIZER_H_