[ARROW-14804] [R] import_from_c() / export_to_c() methods should accept external pointers

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 7.0.0
• Component/s: R
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/30339
• Assignee: Alessandro Molina
• Reporter: Dewey Dunnington
• Created: 24/Nov/21 00:34
• Updated: 11/Jan/23 08:42
• Resolved: 20/Dec/21 17:41

Description

The import and export to C methods for Field, Shema, DataType, Array, RecordBatch, and RecordBatchReader all require the pointer to be passed as a double (casted from uintptr_t casted from *. I imagine there's good reason for this path to exist; however, the R externalptr type and 64-bit integer are more natural types and I think it would not be hard to allow pointers to be passed in this way. A short discussion of this occurred when updating the Python docs on how to pass Array pointers to R.

The implementation lives in arrow_cpp11.h and it seems like it would be easy to allow a user to pass something more R-like while still keeping the double route open for the packages that need it.

I see that this is getting used for pointers that R6 objects are storing for the underlying C++ objects...I imagine there's a good reason for this but I wonder if there's a way to make the places where this interacts with other packages more intuitive.

Issue Links

• is depended upon by: ARROW-15169 [Python] _import_from_c() / _export_to_c() methods should accept capsules
• links to: GitHub Pull Request #11919