/// <summary>
/// Configures the specified pipeline stage to receive log messages, when the current stage has completed running
/// its <see cref="ProcessMessage"/> method. The method must return <c>true</c> to call the following stage.
/// The pipeline stage must use the same log configuration as the current stage and it must not be initialized, yet.
/// </summary>
/// <param name="stage">The pipeline stage that should follow the current stage.</param>
/// <exception cref="ArgumentNullException">
/// <paramref name="stage"/> is <c>null</c>.
/// </exception>
/// <exception cref="ArgumentException">
/// <paramref name="stage"/> is already initialized or its configuration is not the same as the configuration of the current state.
/// </exception>
public void AddNextStage(ProcessingPipelineStage stage)
{
if (stage == null)
{
throw new ArgumentNullException(nameof(stage));
}
if (stage.IsInitialized)
{
throw new ArgumentException("The stage to add must not be initialized.", nameof(stage));
}
if (!ReferenceEquals(stage.Configuration, Configuration))
{
throw new ArgumentException("The stage must use the same configuration as the current stage.", nameof(stage));
}
lock (Sync)
{
var oldNextStages = mNextStages;
var copy = new ProcessingPipelineStage[mNextStages.Length + 1];
Array.Copy(mNextStages, copy, mNextStages.Length);
copy[copy.Length - 1] = stage;
mNextStages = copy;
// initialize the added stage, if this stage is initialized
if (mInitialized)
{
try
{
stage.Initialize();
}
catch (Exception)
{
try
{
stage.Shutdown();
}
catch (Exception ex)
{
// swallow exception to avoid crashing the application, if the exception is not handled properly
Debug.Fail("The pipeline stage threw an exception while shutting down", ex.ToString());
}
mNextStages = oldNextStages;
throw;
}
}
}
}