pyo3/tests/test_gc.rs

#![feature(proc_macro, specialization)]

extern crate pyo3;

use pyo3::prelude::*;
use std::sync::Arc;
use std::cell::RefCell;
use std::sync::atomic::{AtomicBool, Ordering};
use pyo3::ffi;

use pyo3::py::class as pyclass;
use pyo3::py::methods as pymethods;
use pyo3::py::proto as pyproto;

#[macro_use]
mod common;


#[pyclass(freelist=2)]
struct ClassWithFreelist{token: PyToken}

#[test]
fn class_with_freelist() {
    let ptr;
    {
        let gil = Python::acquire_gil();
        let py = gil.python();

        let inst = Py::new(py, |t| ClassWithFreelist{token: t}).unwrap();
        let _inst2 = Py::new(py, |t| ClassWithFreelist{token: t}).unwrap();
        ptr = inst.as_ptr();
        drop(inst);
    }

    {
        let gil = Python::acquire_gil();
        let py = gil.python();

        let inst3 = Py::new(py, |t| ClassWithFreelist{token: t}).unwrap();
        assert_eq!(ptr, inst3.as_ptr());

        let inst4 = Py::new(py, |t| ClassWithFreelist{token: t}).unwrap();
        assert_ne!(ptr, inst4.as_ptr())
    }
}

struct TestDropCall {
    drop_called: Arc<AtomicBool>
}
impl Drop for TestDropCall {
    fn drop(&mut self) {
        self.drop_called.store(true, Ordering::Relaxed);
    }
}

#[allow(dead_code)]
#[pyclass]
struct DataIsDropped {
    member1: TestDropCall,
    member2: TestDropCall,
    token: PyToken,
}

#[test]
fn data_is_dropped() {
    let drop_called1 = Arc::new(AtomicBool::new(false));
    let drop_called2 = Arc::new(AtomicBool::new(false));

    {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let inst = py.init(|t| DataIsDropped{
            member1: TestDropCall { drop_called: Arc::clone(&drop_called1) },
            member2: TestDropCall { drop_called: Arc::clone(&drop_called2) },
            token: t
        }).unwrap();
        assert!(!drop_called1.load(Ordering::Relaxed));
        assert!(!drop_called2.load(Ordering::Relaxed));
        drop(inst);
    }

    assert!(drop_called1.load(Ordering::Relaxed));
    assert!(drop_called2.load(Ordering::Relaxed));
}

#[pyclass]
struct ClassWithDrop {
    token: PyToken,
}
impl Drop for ClassWithDrop {
    fn drop(&mut self) {
        unsafe {
            let py = Python::assume_gil_acquired();

            let _empty1 = PyTuple::empty(py);
            let _empty2: PyObject = PyTuple::empty(py).into();
            let _empty3: &PyObjectRef = py.from_owned_ptr(ffi::PyTuple_New(0));
        }
    }
}

// Test behavior of pythonrun::register_pointers + typeob::dealloc
#[test]
fn create_pointers_in_drop() {
    let _gil = Python::acquire_gil();

    let ptr;
    let cnt;
    {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let empty = PyTuple::empty(py);
        ptr = empty.as_ptr();
        cnt = empty.get_refcnt() - 1;
        let inst = py.init(|t| ClassWithDrop{token: t}).unwrap();
        drop(inst);
    }

    // empty1 and empty2 are still alive (stored in pointers list)
    {
        let _gil = Python::acquire_gil();
        assert_eq!(cnt + 2, unsafe {ffi::Py_REFCNT(ptr)});
    }

    // empty1 and empty2 should be released
    {
        let _gil = Python::acquire_gil();
        assert_eq!(cnt, unsafe {ffi::Py_REFCNT(ptr)});
    }
}

#[allow(dead_code)]
#[pyclass]
struct GCIntegration {
    self_ref: RefCell<PyObject>,
    dropped: TestDropCall,
    token: PyToken,
}

#[pyproto]
impl PyGCProtocol for GCIntegration {
    fn __traverse__(&self, visit: PyVisit) -> Result<(), PyTraverseError> {
        visit.call(&*self.self_ref.borrow())
    }

    fn __clear__(&mut self) {
        *self.self_ref.borrow_mut() = self.py().None();
    }
}

#[test]
fn gc_integration() {
    let drop_called = Arc::new(AtomicBool::new(false));

    {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let inst = Py::new_ref(py, |t| GCIntegration{
            self_ref: RefCell::new(py.None()),
            dropped: TestDropCall { drop_called: Arc::clone(&drop_called) },
            token: t}).unwrap();

        *inst.self_ref.borrow_mut() = inst.into();
    }

    let gil = Python::acquire_gil();
    let py = gil.python();
    py.run("import gc; gc.collect()", None, None).unwrap();
    assert!(drop_called.load(Ordering::Relaxed));
}

#[pyclass(gc)]
struct GCIntegration2 {
    token: PyToken,
}
#[test]
fn gc_integration2() {
    let gil = Python::acquire_gil();
    let py = gil.python();
    let inst = Py::new_ref(py, |t| GCIntegration2{token: t}).unwrap();
    py_run!(py, inst, "import gc; assert inst in gc.get_objects()");
}

#[pyclass(weakref)]
struct WeakRefSupport {
    token: PyToken,
}
#[test]
fn weakref_support() {
    let gil = Python::acquire_gil();
    let py = gil.python();
    let inst = Py::new_ref(py, |t| WeakRefSupport{token: t}).unwrap();
    py_run!(py, inst, "import weakref; assert weakref.ref(inst)() is inst");
}

#[pyclass]
struct BaseClassWithDrop {
    token: PyToken,
    data: Option<Arc<AtomicBool>>,
}

#[pymethods]
impl BaseClassWithDrop {
    #[new]
    fn __new__(obj: &PyRawObject) -> PyResult<()> {
        obj.init(|t| BaseClassWithDrop{token: t, data: None})
    }
}

impl Drop for BaseClassWithDrop {
    fn drop(&mut self) {
        if let Some(ref mut data) = self.data {
            data.store(true, Ordering::Relaxed);
        }
    }
}

#[pyclass(base=BaseClassWithDrop)]
struct SubClassWithDrop {
    token: PyToken,
    data: Option<Arc<AtomicBool>>,
}

#[pymethods]
impl SubClassWithDrop {
    #[new]
    fn __new__(obj: &PyRawObject) -> PyResult<()> {
        obj.init(|t| SubClassWithDrop{token: t, data: None})?;
        BaseClassWithDrop::__new__(obj)
    }
}

impl Drop for SubClassWithDrop {
    fn drop(&mut self) {
        if let Some(ref mut data) = self.data {
            data.store(true, Ordering::Relaxed);
        }
    }
}

#[test]
fn inheritance_with_new_methods_with_drop() {
    let drop_called1 = Arc::new(AtomicBool::new(false));
    let drop_called2 = Arc::new(AtomicBool::new(false));

    {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let _typebase = py.get_type::<BaseClassWithDrop>();
        let typeobj = py.get_type::<SubClassWithDrop>();
        let inst = typeobj.call(NoArgs, NoArgs).unwrap();

        let obj = SubClassWithDrop::try_from_mut(inst).unwrap();
        obj.data = Some(Arc::clone(&drop_called1));

        let base = obj.get_mut_base();
        base.data = Some(Arc::clone(&drop_called2));
    }

    assert!(drop_called1.load(Ordering::Relaxed));
    assert!(drop_called2.load(Ordering::Relaxed));
}