rust-cpython: make PyLeakedRef operations relatively safe
This patch encapsulates the access to the leaked reference to make most
leaked-ref operations safe. The only exception is leaked_ref.map(). I
couldn't figure out how to allow arbitrary map operation safely over an
unsafe static reference. See the docstring and inline comment for details.
Now leak_immutable() can be safely implemented as the PyLeakedRef owns
its inner data.
use cpython::{PyDict, PyObject, PyResult, PyTuple, Python};
#[allow(unused)]
pub fn print_python_trace(py: Python) -> PyResult<PyObject> {
eprintln!("===============================");
eprintln!("Printing Python stack from Rust");
eprintln!("===============================");
let traceback = py.import("traceback")?;
let sys = py.import("sys")?;
let kwargs = PyDict::new(py);
kwargs.set_item(py, "file", sys.get(py, "stderr")?)?;
traceback.call(py, "print_stack", PyTuple::new(py, &[]), Some(&kwargs))
}