import pytest

from pybind11_tests import call_policies as m

from pybind11_tests import ConstructorStats

def test_keep_alive_argument(capture):

    n_inst = ConstructorStats.detail_reg_inst()

    with capture:

        p = m.Parent()

    assert capture == "Allocating parent."

    with capture:

        p.addChild(m.Child())

        assert ConstructorStats.detail_reg_inst() == n_inst + 1

    assert capture == """

        Allocating child.

        Releasing child.

    """

    with capture:

        del p

        assert ConstructorStats.detail_reg_inst() == n_inst

    assert capture == "Releasing parent."

    with capture:

        p = m.Parent()

    assert capture == "Allocating parent."

    with capture:

        p.addChildKeepAlive(m.Child())

        assert ConstructorStats.detail_reg_inst() == n_inst + 2

    assert capture == "Allocating child."

    with capture:

        del p

        assert ConstructorStats.detail_reg_inst() == n_inst

    assert capture == """

        Releasing parent.

        Releasing child.

    """

def test_keep_alive_return_value(capture):

    n_inst = ConstructorStats.detail_reg_inst()

    with capture:

        p = m.Parent()

    assert capture == "Allocating parent."

    with capture:

        p.returnChild()

        assert ConstructorStats.detail_reg_inst() == n_inst + 1

    assert capture == """

        Allocating child.

        Releasing child.

    """

    with capture:

        del p

        assert ConstructorStats.detail_reg_inst() == n_inst

    assert capture == "Releasing parent."

    with capture:

        p = m.Parent()

    assert capture == "Allocating parent."

    with capture:

        p.returnChildKeepAlive()

        assert ConstructorStats.detail_reg_inst() == n_inst + 2

    assert capture == "Allocating child."

    with capture:

        del p

        assert ConstructorStats.detail_reg_inst() == n_inst

    assert capture == """

        Releasing parent.

        Releasing child.

    """

# https://bitbucket.org/pypy/pypy/issues/2447

@pytest.unsupported_on_pypy

def test_alive_gc(capture):

    n_inst = ConstructorStats.detail_reg_inst()

    p = m.ParentGC()

    p.addChildKeepAlive(m.Child())

    assert ConstructorStats.detail_reg_inst() == n_inst + 2

    lst = [p]

    lst.append(lst)   # creates a circular reference

    with capture:

        del p, lst

        assert ConstructorStats.detail_reg_inst() == n_inst

    assert capture == """

        Releasing parent.

        Releasing child.

    """

def test_alive_gc_derived(capture):

    class Derived(m.Parent):

        pass

    n_inst = ConstructorStats.detail_reg_inst()

    p = Derived()

    p.addChildKeepAlive(m.Child())

    assert ConstructorStats.detail_reg_inst() == n_inst + 2

    lst = [p]

    lst.append(lst)   # creates a circular reference

    with capture:

        del p, lst

        assert ConstructorStats.detail_reg_inst() == n_inst

    assert capture == """

        Releasing parent.

        Releasing child.

    """

def test_alive_gc_multi_derived(capture):

    class Derived(m.Parent, m.Child):

        def __init__(self):

            m.Parent.__init__(self)

            m.Child.__init__(self)

    n_inst = ConstructorStats.detail_reg_inst()

    p = Derived()

    p.addChildKeepAlive(m.Child())

    # +3 rather than +2 because Derived corresponds to two registered instances

    assert ConstructorStats.detail_reg_inst() == n_inst + 3

    lst = [p]

    lst.append(lst)   # creates a circular reference

    with capture:

        del p, lst

        assert ConstructorStats.detail_reg_inst() == n_inst

    assert capture == """

        Releasing parent.

        Releasing child.

        Releasing child.

    """

def test_return_none(capture):

    n_inst = ConstructorStats.detail_reg_inst()

    with capture:

        p = m.Parent()

    assert capture == "Allocating parent."

    with capture:

        p.returnNullChildKeepAliveChild()

        assert ConstructorStats.detail_reg_inst() == n_inst + 1

    assert capture == ""

    with capture:

        del p

        assert ConstructorStats.detail_reg_inst() == n_inst

    assert capture == "Releasing parent."

    with capture:

        p = m.Parent()

    assert capture == "Allocating parent."

    with capture:

        p.returnNullChildKeepAliveParent()

        assert ConstructorStats.detail_reg_inst() == n_inst + 1

    assert capture == ""

    with capture:

        del p

        assert ConstructorStats.detail_reg_inst() == n_inst

    assert capture == "Releasing parent."

def test_keep_alive_constructor(capture):

    n_inst = ConstructorStats.detail_reg_inst()

    with capture:

        p = m.Parent(m.Child())

        assert ConstructorStats.detail_reg_inst() == n_inst + 2

    assert capture == """

        Allocating child.

        Allocating parent.

    """

    with capture:

        del p

        assert ConstructorStats.detail_reg_inst() == n_inst

    assert capture == """

        Releasing parent.

        Releasing child.

    """

def test_call_guard():

    assert m.unguarded_call() == "unguarded"

    assert m.guarded_call() == "guarded"

    assert m.multiple_guards_correct_order() == "guarded & guarded"

    assert m.multiple_guards_wrong_order() == "unguarded & guarded"

    if hasattr(m, "with_gil"):

        assert m.with_gil() == "GIL held"

        assert m.without_gil() == "GIL released"