The new method `ArrayHandle::DeepCopy` had the pattern such that the
data in the `this` array was pushed to the provided destination array.
However, this is the opposite pattern used in the equivalent method in
VTK, which takes the data from the provided array and copies it to
`this` array.
So, swap the pattern to match that of VTK. Also, make the method name
more descriptive by renaming it to `DeepCopyFrom`. Hopefully, users will
read that to mean given the `ArrayHandle`, you copy data from the other
provided `ArrayHandle`.
A recent modification to `ArrayCopy` created a fast path for when
copying arrays of the same type. This fast path just deep copies the
buffers. The issue was that the buffer copy was creating new buffers
instead of updating the existing buffers. The passed in `ArrayHandle`
would get updated to the new buffers, but any other `ArrayHandle`s
sharing those buffers would still have the old versions. That would lead
to unexpected errors in code like this.
```cpp
vtkm::cont::ArrayHandle<T> outArray1;
vtkm::cont::ArrayHandle<T> outArray2 = outArray1;
vtkm::cont::ArrayCopy(inArray, outArray2);
```
If `inArray` was a different type than `outArray2`, then the data for
both `outArray1` and `outArray2` would be updated (which is the expected
behavior for something considered a "pointer"). However, if `inArray`
was the same type as `outArray2`, then the fast path would change
`outArray2` but leave `outArray1` the same.
This behavior has been corrected so that, in this case, the data of
`outArray1` always follows that of `outArray2`.
The parallel sorts in the device adapter are documented to not be
stable. Up until recently, the sorts for all the supported devices
happened to be stable (or at least provided a stable sort where needed).
However, the recent Kokkos adapter provides a sort that is no stable.
This broke some tests that relied on stable sorts when they should not
have.
Fix the tests that relied on stable sort to check the results.
C++ was not resolving the overloads of `ArrayCopyImpl` as expected,
which was causing `ArrayCopy` to sometimes use a less efficient method
for copying.
Also fix an issue with `Buffer::DeepCopy` that caused a deadlock when
copying a buffer that was not actually allocated anywhere (as well as
failing to copy the metadata, which was probably the whole point).
This limitation is caused by the fact that VTK-m caches compiler
location during the build stage for these tests, and this fails
on the test image as the compiler might not exist or is in a
different path
The old style `ArrayHandle` stored most of its state, including the
data, in the `vtkm::cont::internal::Storage` object (templated to the
type of array). The new style of `ArrayHandle` stores the data itself in
`Buffer` objects, and recent changes to `Buffer` allow metadata to be
stored there, too.
These changes make it pretty unnecessary to hold any state at all in the
`Storage` object. This is good since the sharing of state from one type
of `ArrayHandle` to another (such as by transforming the data), can be
done by just sharing the `Buffer` objects.
To reinforce this behavior, the `Storage` object has been changed to
make it completely stateless. All the methods of `Storage` must be
marked as `static`.