Method SetOutput

Modules/Core/Common/src/itkProcessObject.cxx:417–478

void
ProcessObject::SetOutput(const DataObjectIdentifierType & name, DataObject * output)
{
  /*
    Set an Output of this filter. This method
   * does Register()/UnRegister() manually to
   * deal with the fact that smart pointers aren't
   * around to do the reference counting.
   */

  // copy the key, because it might be destroyed in that method, so a reference
  // is not enough.
  const DataObjectIdentifierType key = name;

  if (key.empty())
  {
    itkExceptionMacro("An empty string can't be used as an output identifier");
  }

  // does this change anything?
  const auto it = m_Outputs.find(key);
  if (it != m_Outputs.end() && it->second.GetPointer() == output)
  {
    return;
  }

  // Keep a handle to the original output and disconnect the old output from
  // the pipeline
  DataObjectPointer oldOutput;
  if (m_Outputs[key])
  {
    oldOutput = m_Outputs[key];
    m_Outputs[key]->DisconnectSource(this, key);
  }

  if (output)
  {
    output->ConnectSource(this, key);
  }
  // save the current reference (which releases the previous reference)
  m_Outputs[key] = output;

  // if we are clearing an output, we need to create a new blank output
  // so we are prepared for the next Update(). this copies the requested
  // region ivar
  if (!m_Outputs[key])
  {
    itkDebugMacro(" creating new output object.");
    const DataObjectPointer newOutput = this->MakeOutput(key);
    this->SetOutput(key, newOutput);

    // If we had an output object before, copy the requested region
    // ivars and release data flag to the new output
    if (oldOutput)
    {
      newOutput->SetRequestedRegion(oldOutput);
      newOutput->SetReleaseDataFlag(oldOutput->GetReleaseDataFlag());
    }