Protobuf，CodedInputStream正在解析部分消息

我正在尝试实现与java版本兼容的protobuf发送/接收，该版本首先包含varint32前缀。

我几乎已经让它工作了，但由于某种原因，有些消息变得不完整，并使assert（）失败。

/receiver.cpp:69: void tcp_connection::handle_read_message(const boost::system::error_code&, size_t): Assertion `line.ParseFromCodedStream(&input)' failed.

semder.pp

boost::asio::streambuf buffer;
std::ostream writer(&buffer);
bool packet_full = false;
uint32_t sent_lines = 0;
{ //new scope for protobuf streams, these flush in dtor
    google::protobuf::io::OstreamOutputStream osostream(&writer);
    google::protobuf::io::CodedOutputStream output(&osostream);
    std::string lines;
    while(std::getline(reader, line)) {
        lines += line + "n";
        ++sent_lines;
        if(sent_lines > 100) {
            packet_full = true;
            break;
        }
    }
    if(!lines.empty()) {
        msg->set_text(lines);
        const uint32_t size = msg->ByteSize();
        output.WriteVarint32(size);
        uint8_t* buffer = output.GetDirectBufferForNBytesAndAdvance(size);
        if(buffer != 0) {
            msg->SerializeWithCachedSizesToArray(buffer);
        } else {
            msg->SerializeWithCachedSizes(&output);
        }
}
if(sent_lines > 0) {
    sock.send(buffer.data());
    if(!packet_full && !reader.eof()) { //Read ended, and not due to end of file
        std::cout << "An error occured" << std::endl;
        break;
    }
    reader.clear(); //clear EOF flag
}

接收器.cpp

这是一个助推回调。

成员变量：

boost::asio::ip::tcp::socket socket_;
boost::asio::streambuf buffer_;

代码

void handle_read_message(const boost::system::error_code& error,
                      size_t bytes_transferred) {

   if(!error) {
      buffer_.commit(bytes_transferred);
      std::istream reader(&buffer_);
      google::protobuf::io::IstreamInputStream isistream(&reader);
      google::protobuf::io::CodedInputStream input(&isistream);
      uint32_t size = 0;
      assert(input.ReadVarint32(&size));
      auto limit = input.PushLimit(size);
      msgs::Line line;
      assert(line.ParseFromCodedStream(&input));
      assert(input.ConsumedEntireMessage());
      input.PopLimit(limit);
      start();  
    } else {
      std::cout <<"error during handle_read_message: " << error << std::endl;
    }
}

这主要基于https://stackoverflow.com/a/22899712

编辑：新的接收器版本，reader_现在是一个成员变量：

void handle_read_message(const boost::system::error_code& error,
                          size_t bytes_transferred) {
    std::cout << "handle_read_message(" << bytes_transferred << ")" <<std::endl;
    if(!error) {
      buffer_.commit(bytes_transferred);
      uint32_t size = 0;
      google::protobuf::io::IstreamInputStream isistream_(&reader_);
      {
        google::protobuf::io::CodedInputStream input(&isistream_);
        if(!input.ReadVarint32(&size)) {
          std::cout << "Failed to read size, waiting for more data" << std::endl;
          start();
          return;
        }
      }
      std::size_t varint_size = isistream_.ByteCount();
      std::cout <<"varintsize: " << varint_size << ", size: " << size << ", have bytes: " << buffer_.size() << std::endl;
      if(varint_size + size > buffer_.size()) {
        std::cout << "Not enough data received, waiting for more" << std::endl;
        start();
        return;
      }
      google::protobuf::io::CodedInputStream input(&isistream_);
      auto limit = input.PushLimit(size);
      msgs::Line line;
      assert(line.ParseFromCodedStream(&input));
      std::cout << line.text() << std::endl;
      assert(input.ConsumedEntireMessage());
      input.PopLimit(limit);
      start();  
    } else {
      std::cout <<"error during handle_read_message: " << error << std::endl;
    } 
  }