Method cancelled

be/src/exec/scanner-context.cc:378–382

}

bool ScannerContext::cancelled() const {
  if (state_->is_cancelled()) return true;
  if (!scan_node_->HasRowBatchQueue()) return false;
  return static_cast<HdfsScanNode*>(scan_node_)->done();
}

bool ScannerContext::Stream::ValidateBufferPointers() const {
  // If there are bytes left in the boundary buffer, the output buffer pointers must point