Method OperDone

be/src/runtime/io/request-context.cc:232–256

}

void RequestContext::OperDone(RequestRange* range, const Status& status) {
  DCHECK(range != nullptr);

  // Copy disk_id before running callback: the callback may modify range.
  int disk_id = range->disk_id();

  // Execute the callback before decrementing the thread count. Otherwise
  // RequestContext::Cancel() that waits for the disk ref count to be 0 will
  // return, creating a race, e.g. see IMPALA-1890.
  // The status of the operation does not affect the status of the request context.
  if (range->request_type() == RequestType::WRITE) {
    (static_cast<WriteRange*>(range))->callback()(status);
  } else {
    DCHECK(range->request_type() == RequestType::FILE_UPLOAD
        || range->request_type() == RequestType::FILE_FETCH);
    (static_cast<RemoteOperRange*>(range))->callback()(status);
  }
  {
    unique_lock<mutex> lock(lock_);
    DCHECK(Validate()) << endl << DebugString();
    RequestContext::PerDiskState& state = disk_states_[disk_id];
    state.DecrementDiskThread(lock, this);
    --state.num_remaining_ranges();
  }
}

// Cancellation of a RequestContext requires coordination from multiple threads that may
// hold references to the context: