RpcWritable.java 文件源码

@SuppressWarnings("unchecked")
@Override
<T> T readFrom(ByteBuffer bb) throws IOException {
  // using the parser with a byte[]-backed coded input stream is the
  // most efficient way to deserialize a protobuf.  it has a direct
  // path to the PB ctor that doesn't create multi-layered streams
  // that internally buffer.
  CodedInputStream cis = CodedInputStream.newInstance(
      bb.array(), bb.position() + bb.arrayOffset(), bb.remaining());
  try {
    cis.pushLimit(cis.readRawVarint32());
    message = message.getParserForType().parseFrom(cis);
    cis.checkLastTagWas(0);
  } finally {
    // advance over the bytes read.
    bb.position(bb.position() + cis.getTotalBytesRead());
  }
  return (T)message;
}