Implement the buffer protocol safely

[jimy-byerley]

Hi !
I'm using rust as backend for a python module I'm working on, to get high performances on mesh operations. The data is owned by some rust Vecs but I would like to expose its content to python, to make possible extend the module with pure python (or at least to get some data points).

So I'm trying to implement the buffer protocol for my structs. I seen this page in pyo3. But it relies on pointers so it's unsafe.
But the buffer protocol is not incompatible with pyo3's safety since i read in the python doc that the memoryview object kept a hook on the viewed object

Is there a way to safely implement the buffer protocol for rust objects exposed by a #[pyclass] statement ?

[kngwyu]

Thank you for reporting it.
I think our current implementation is really bad and needs to be refined.
I haven't done refactoring for class/buffer.rs(because of some reasons: its complicated design, integration with PyBuffer, and difficulty to sync with rust-numpy), but it's time to do it.

[jimy-byerley]

I don't know for the code that is behind it (I can imagine that it can be easily headache with all these structs and traits ;) but I find the API of the PyBuffer quite elegant by now: one method to get it from any object, one method to get the buffer in the final type :)

[kngwyu]

Sorry, I'm saying about class/buffer.rs where PyBufferProtocol is.
Though PyBuffer also can be changed a bit...(e.g., it can have lifetime py)

[davidhewitt]

This is now tracked in #1884 as part of the move to #[pymethods].