/// <summary>
/// Returns the next reference.
/// </summary>
/// <returns></returns>
public override IReference Next()
{
lock (DataLock)
{
IReference reference = null;
// enumerate pre-defined references.
// always call first to ensure any pushed-back references are returned first.
reference = base.Next();
if (reference != null)
{
return reference;
}
// check that the root exists.
if (m_area == null || !m_area.Exists)
{
return null;
}
// don't start browsing huge number of references when only internal references are requested.
if (InternalOnly)
{
return null;
}
// start with directories.
if (m_stage == Stage.Begin)
{
m_stage = Stage.Directories;
m_directories = m_area.GetDirectories();
m_position = 0;
}
// enumerate directories.
if (m_stage == Stage.Directories)
{
if (IsRequired(ReferenceTypeIds.Organizes, false))
{
reference = NextChild();
if (reference != null)
{
return reference;
}
}
m_stage = Stage.Files;
m_files = m_area.GetFiles("*.csv");
m_position = 0;
}
// enumerate files.
if (m_stage == Stage.Files)
{
if (IsRequired(ReferenceTypeIds.Organizes, false))
{
reference = NextChild();
if (reference != null)
{
return reference;
}
}
m_stage = Stage.Parents;
m_position = 0;
}
// enumerate parents.
if (m_stage == Stage.Parents)
{
if (IsRequired(ReferenceTypeIds.Organizes, true))
{
if (m_isRoot)
{
reference = new NodeStateReference(ReferenceTypeIds.Organizes, true, ObjectIds.ObjectsFolder);
}
else
{
// create the parent area.
AreaState parent = new AreaState(SystemContext, m_area.Parent);
// construct the reference.
reference = new NodeStateReference(ReferenceTypeIds.Organizes, true, parent);
}
m_stage = Stage.Done;
m_position = 0;
return reference;
}
}
// all done.
return null;
}
}
