PyArcVec

arc_vec.rs

mod arc_buffer {
    use lazy_static::lazy_static;
    use pyo3::ffi;
    use pyo3::prelude::*;
    use pyo3::AsPyPointer;
    use std::sync::atomic::{AtomicUsize, Ordering};
    use std::sync::Arc;

    lazy_static! {
        static ref COUNTER: AtomicUsize = AtomicUsize::default();
    }

    #[pyclass]
    pub struct ArcVec {
        data: Arc<Vec<u8>>,
        // Just for testing
        id: usize,
    }

    impl ArcVec {
        pub fn new(data: Arc<Vec<u8>>) -> ArcVec {
            ArcVec {
                data,
                id: COUNTER.fetch_add(1, Ordering::SeqCst),
            }
        }
    }

    #[pyproto]
    impl pyo3::class::buffer::PyBufferProtocol for ArcVec {
        fn bf_getbuffer(
            slf: PyRefMut<Self>,
            view: *mut ffi::Py_buffer,
            flags: std::os::raw::c_int,
        ) -> PyResult<()> {
            println!("getbuffer {}", slf.id);
            if view.is_null() {
                return Err(pyo3::exceptions::PyBufferError::new_err("View is null"));
            }

            if (flags & ffi::PyBUF_WRITABLE) == ffi::PyBUF_WRITABLE {
                return Err(pyo3::exceptions::PyBufferError::new_err(
                    "Object is not writable",
                ));
            }

            unsafe {
                (*view).obj = slf.as_ptr();
                ffi::Py_INCREF((*view).obj);
            }

            let bytes = slf.data.as_ref();

            unsafe {
                (*view).buf = bytes.as_ptr() as *mut std::os::raw::c_void;
                (*view).len = bytes.len() as isize;
                (*view).readonly = 1;
                (*view).itemsize = 1;

                (*view).format = std::ptr::null_mut();
                if (flags & ffi::PyBUF_FORMAT) == ffi::PyBUF_FORMAT {
                    let msg = std::ffi::CStr::from_bytes_with_nul(b"B\0").unwrap();
                    (*view).format = msg.as_ptr() as *mut _;
                }

                (*view).ndim = 1;
                (*view).shape = std::ptr::null_mut();
                if (flags & ffi::PyBUF_ND) == ffi::PyBUF_ND {
                    (*view).shape = (&((*view).len)) as *const _ as *mut _;
                }

                (*view).strides = std::ptr::null_mut();
                if (flags & ffi::PyBUF_STRIDES) == ffi::PyBUF_STRIDES {
                    (*view).strides = &((*view).itemsize) as *const _ as *mut _;
                }

                (*view).suboffsets = std::ptr::null_mut();
                (*view).internal = std::ptr::null_mut();
            }

            Ok(())
        }

        fn bf_releasebuffer(slf: PyRefMut<Self>, _view: *mut ffi::Py_buffer) {
            println!("releasebuffer {}", slf.id);
        }
    }

    impl Drop for ArcVec {
        fn drop(&mut self) {
            println!("Dropped {}", &self.id);
        }
    }
}

Looks like this is a bit outdated and not working with the latest version of Pyo3 (0.18.1) any version more recent or some pointers?