Function getStripeFooter

c++/src/Reader.cc:589–625

  }

  proto::StripeFooter getStripeFooter(const proto::StripeInformation& info,
                                      FileContents& contents) {
    uint64_t stripeFooterStart = info.offset() + info.index_length() + info.data_length();
    uint64_t stripeFooterLength = info.footer_length();

    std::unique_ptr<SeekableInputStream> pbStream;
    BufferSlice slice;

    {
      std::lock_guard<std::mutex> lock(contents.readCacheMutex);
      if (contents.readCache) {
        slice = contents.readCache->read(ReadRange(stripeFooterStart, stripeFooterLength));
      }
    }
    if (slice.buffer) {
      pbStream = std::make_unique<SeekableArrayInputStream>(slice.buffer->data() + slice.offset,
                                                            slice.length);
    } else {
      pbStream = std::make_unique<SeekableFileInputStream>(contents.stream.get(), stripeFooterStart,
                                                           stripeFooterLength, *contents.pool);
    }
    pbStream = createDecompressor(contents.compression, std::move(pbStream), contents.blockSize,
                                  *contents.pool, contents.readerMetrics);

    proto::StripeFooter result;
    if (!result.ParseFromZeroCopyStream(pbStream.get())) {
      throw ParseError(std::string("bad StripeFooter from ") + pbStream->getName());
    }
    // Verify StripeFooter in case it's corrupt
    if (result.columns_size() != contents.footer->types_size()) {
      std::stringstream msg;
      msg << "bad number of ColumnEncodings in StripeFooter: expected="
          << contents.footer->types_size() << ", actual=" << result.columns_size();
      throw ParseError(msg.str());
    }
    return result;
  }

  ReaderImpl::ReaderImpl(std::shared_ptr<FileContents> contents, const ReaderOptions& opts,
                         uint64_t fileLength, uint64_t postscriptLength)