Blink-compatible deserialization of old object format.

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 94 matching lines @@
   /*
    * Runs version detection logic, which may fail if the format is invalid.
    */
   Maybe<bool> ReadHeader() WARN_UNUSED_RESULT;
 
   /*
    * Deserializes a V8 object from the buffer.
    */
   MaybeHandle<Object> ReadObject() WARN_UNUSED_RESULT;
 
+  /*
+   * 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;
+
  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.
@@ skipping 29 matching lines @@
   Handle<SeededNumberDictionary> id_map_;  // always a global handle
   uint32_t next_id_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(ValueDeserializer);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_VALUE_SERIALIZER_H_