This is done to avoid warnings when compiling VTK-m consumers
with different defaults for symbol visiblity. AKA avoid warnings
like:
```
warning: ‘vtkm::worklet::WorkletMapField’ declared with greater visibility than the type of its field ‘vtkm::worklet::WorkletMapField::<anonymous>’ [-Wattributes]
class WorkletMapField : public vtkm::worklet::internal::WorkletBase
^~~~~~~~~~~~~~~
```
Sandia National Laboratories recently changed management from the
Sandia Corporation to the National Technology & Engineering Solutions
of Sandia, LLC (NTESS). The copyright statements need to be updated
accordingly.
Previously WorkletInvokeFunctor inherited from vtkm::exec::FunctorBase,
which is also the base class for all users Worklets and for all functors
based to DeviceAdapter::Schedule.
This is done for a few reasons. The first is that we reduce the
minimum size of user worklets. Previously the users worklet would hold
a reference to the error message, and so would the wrapper class added
when calling DeviceAdapter::Schedule. Now we only have the users worklet
holding a reference.
Second, by refactoring to have two base classes we can better improve
the documentation on what responsibilities FunctorBase.h has, compared
to TaskBase.
Change the VTKM_CONT_EXPORT to VTKM_CONT. (Likewise for EXEC and
EXEC_CONT.) Remove the inline from these macros so that they can be
applied to everything, including implementations in a library.
Because inline is not declared in these modifies, you have to add the
keyword to functions and methods where the implementation is not inlined
in the class.
Whenever creating a functor to be launched in the execution environment
using the device adapter Schedule algorithm, you had to also create a
couple of methods to handle error message buffers. For convenience, lots
of code started to just inherit from WorkletBase. Although this worked,
it was a misnomer (and might cause problems in the future if worklets
later require different things from its base). To get around this
problem, add a FunctorBase class that is intended to be used as the
superclass to functors called with Schedule.
