void setNumChannels()

in pedalboard/ExternalPlugin.h [817:877]
43 lines of code
17 McCabe index (conditional complexity)

  void setNumChannels(int numChannels) {
    if (!pluginInstance)
      return;

    if (numChannels == 0)
      return;

    auto mainInputBus = pluginInstance->getBus(true, 0);
    auto mainOutputBus = pluginInstance->getBus(false, 0);

    // Try to disable all non-main input buses if possible:
    for (int i = 1; i < pluginInstance->getBusCount(true); i++) {
      auto *bus = pluginInstance->getBus(true, i);
      if (bus->isNumberOfChannelsSupported(0))
        bus->enable(false);
    }

    // ...and all non-main output buses too:
    for (int i = 1; i < pluginInstance->getBusCount(false); i++) {
      auto *bus = pluginInstance->getBus(false, i);
      if (bus->isNumberOfChannelsSupported(0))
        bus->enable(false);
    }

    if ((!mainInputBus || mainInputBus->getNumberOfChannels() == numChannels) &&
        mainOutputBus->getNumberOfChannels() == numChannels) {
      return;
    }

    // Cache these values in case the plugin fails to update:
    auto previousInputChannelCount =
        mainInputBus ? mainInputBus->getNumberOfChannels() : 0;
    auto previousOutputChannelCount = mainOutputBus->getNumberOfChannels();

    // Try to change the input and output bus channel counts...
    if (mainInputBus)
      mainInputBus->setNumberOfChannels(numChannels);
    mainOutputBus->setNumberOfChannels(numChannels);

    // If, post-reload, we still can't use the right number of channels, let's
    // conclude the plugin doesn't allow this channel count.
    if ((!mainInputBus || mainInputBus->getNumberOfChannels() != numChannels) ||
        mainOutputBus->getNumberOfChannels() != numChannels) {

      // Reset the bus configuration to what it was before, so we don't
      // leave one of the buses smaller than the other:
      if (mainInputBus)
        mainInputBus->setNumberOfChannels(previousInputChannelCount);
      mainOutputBus->setNumberOfChannels(previousOutputChannelCount);

      throw std::invalid_argument(
          "Plugin '" + pluginInstance->getName().toStdString() +
          "' does not support " + std::to_string(numChannels) +
          "-channel output. (Main bus currently expects " +
          std::to_string(mainInputBus ? mainInputBus->getNumberOfChannels()
                                      : 0) +
          " input channels and " +
          std::to_string(mainOutputBus->getNumberOfChannels()) +
          " output channels.)");
    }
  }