bool LengthFieldBasedFrameDecoder::decode()

in wangle/codec/LengthFieldBasedFrameDecoder.cpp [42:86]

• 37 lines of code
• 6 McCabe index (conditional complexity)

bool LengthFieldBasedFrameDecoder::decode(
    Context* ctx,
    IOBufQueue& buf,
    std::unique_ptr<IOBuf>& result,
    size_t&) {
  // discarding too long frame
  if (buf.chainLength() < lengthFieldEndOffset_) {
    return false;
  }

  uint64_t frameLength = getUnadjustedFrameLength(
      buf, lengthFieldOffset_, lengthFieldLength_, networkByteOrder_);

  frameLength += lengthAdjustment_ + lengthFieldEndOffset_;

  if (frameLength < lengthFieldEndOffset_) {
    buf.trimStart(lengthFieldEndOffset_);
    ctx->fireReadException(
        folly::make_exception_wrapper<std::runtime_error>("Frame too small"));
    return false;
  }

  if (frameLength > maxFrameLength_) {
    buf.trimStartAtMost(frameLength);
    ctx->fireReadException(folly::make_exception_wrapper<std::runtime_error>(
        "Frame larger than " + folly::to<std::string>(maxFrameLength_)));
    return false;
  }

  if (buf.chainLength() < frameLength) {
    return false;
  }

  if (initialBytesToStrip_ > frameLength) {
    buf.trimStart(frameLength);
    ctx->fireReadException(folly::make_exception_wrapper<std::runtime_error>(
        "InitialBytesToSkip larger than frame"));
    return false;
  }

  buf.trimStart(initialBytesToStrip_);
  int actualFrameLength = static_cast<int>(frameLength) - initialBytesToStrip_;
  result = buf.split(actualFrameLength);
  return true;
}