mirror of
https://github.com/pybind/pybind11.git
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464d98962d
This allows you to use:
cls.def(py::init(&factory_function));
where `factory_function` returns a pointer, holder, or value of the
class type (or a derived type). Various compile-time checks
(static_asserts) are performed to ensure the function is valid, and
various run-time type checks where necessary.
Some other details of this feature:
- The `py::init` name doesn't conflict with the templated no-argument
`py::init<...>()`, but keeps the naming consistent: the existing
templated, no-argument one wraps constructors, the no-template,
function-argument one wraps factory functions.
- If returning a CppClass (whether by value or pointer) when an CppAlias
is required (i.e. python-side inheritance and a declared alias), a
dynamic_cast to the alias is attempted (for the pointer version); if
it fails, or if returned by value, an Alias(Class &&) constructor
is invoked. If this constructor doesn't exist, a runtime error occurs.
- for holder returns when an alias is required, we try a dynamic_cast of
the wrapped pointer to the alias to see if it is already an alias
instance; if it isn't, we raise an error.
- `py::init(class_factory, alias_factory)` is also available that takes
two factories: the first is called when an alias is not needed, the
second when it is.
- Reimplement factory instance clearing. The previous implementation
failed under python-side multiple inheritance: *each* inherited
type's factory init would clear the instance instead of only setting
its own type value. The new implementation here clears just the
relevant value pointer.
- dealloc is updated to explicitly set the leftover value pointer to
nullptr and the `holder_constructed` flag to false so that it can be
used to clear preallocated value without needing to rebuild the
instance internals data.
- Added various tests to test out new allocation/deallocation code.
- With preallocation now done lazily, init factory holders can
completely avoid the extra overhead of needing an extra
allocation/deallocation.
- Updated documentation to make factory constructors the default
advanced constructor style.
- If an `__init__` is called a second time, we have two choices: we can
throw away the first instance, replacing it with the second; or we can
ignore the second call. The latter is slightly easier, so do that.
372 lines
11 KiB
Python
372 lines
11 KiB
Python
import pytest
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from pybind11_tests import virtual_functions as m
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from pybind11_tests import ConstructorStats
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def test_override(capture, msg):
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class ExtendedExampleVirt(m.ExampleVirt):
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def __init__(self, state):
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super(ExtendedExampleVirt, self).__init__(state + 1)
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self.data = "Hello world"
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def run(self, value):
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print('ExtendedExampleVirt::run(%i), calling parent..' % value)
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return super(ExtendedExampleVirt, self).run(value + 1)
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def run_bool(self):
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print('ExtendedExampleVirt::run_bool()')
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return False
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def get_string1(self):
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return "override1"
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def pure_virtual(self):
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print('ExtendedExampleVirt::pure_virtual(): %s' % self.data)
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class ExtendedExampleVirt2(ExtendedExampleVirt):
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def __init__(self, state):
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super(ExtendedExampleVirt2, self).__init__(state + 1)
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def get_string2(self):
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return "override2"
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ex12 = m.ExampleVirt(10)
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with capture:
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assert m.runExampleVirt(ex12, 20) == 30
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assert capture == """
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Original implementation of ExampleVirt::run(state=10, value=20, str1=default1, str2=default2)
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""" # noqa: E501 line too long
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with pytest.raises(RuntimeError) as excinfo:
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m.runExampleVirtVirtual(ex12)
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assert msg(excinfo.value) == 'Tried to call pure virtual function "ExampleVirt::pure_virtual"'
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ex12p = ExtendedExampleVirt(10)
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with capture:
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assert m.runExampleVirt(ex12p, 20) == 32
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assert capture == """
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ExtendedExampleVirt::run(20), calling parent..
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Original implementation of ExampleVirt::run(state=11, value=21, str1=override1, str2=default2)
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""" # noqa: E501 line too long
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with capture:
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assert m.runExampleVirtBool(ex12p) is False
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assert capture == "ExtendedExampleVirt::run_bool()"
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with capture:
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m.runExampleVirtVirtual(ex12p)
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assert capture == "ExtendedExampleVirt::pure_virtual(): Hello world"
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ex12p2 = ExtendedExampleVirt2(15)
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with capture:
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assert m.runExampleVirt(ex12p2, 50) == 68
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assert capture == """
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ExtendedExampleVirt::run(50), calling parent..
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Original implementation of ExampleVirt::run(state=17, value=51, str1=override1, str2=override2)
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""" # noqa: E501 line too long
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cstats = ConstructorStats.get(m.ExampleVirt)
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assert cstats.alive() == 3
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del ex12, ex12p, ex12p2
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assert cstats.alive() == 0
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assert cstats.values() == ['10', '11', '17']
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assert cstats.copy_constructions == 0
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assert cstats.move_constructions >= 0
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def test_alias_delay_initialization1(capture):
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"""`A` only initializes its trampoline class when we inherit from it
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If we just create and use an A instance directly, the trampoline initialization is
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bypassed and we only initialize an A() instead (for performance reasons).
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"""
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class B(m.A):
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def __init__(self):
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super(B, self).__init__()
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def f(self):
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print("In python f()")
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# C++ version
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with capture:
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a = m.A()
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m.call_f(a)
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del a
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pytest.gc_collect()
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assert capture == "A.f()"
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# Python version
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with capture:
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b = B()
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m.call_f(b)
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del b
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pytest.gc_collect()
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assert capture == """
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PyA.PyA()
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PyA.f()
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In python f()
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PyA.~PyA()
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"""
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def test_alias_delay_initialization2(capture):
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"""`A2`, unlike the above, is configured to always initialize the alias
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While the extra initialization and extra class layer has small virtual dispatch
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performance penalty, it also allows us to do more things with the trampoline
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class such as defining local variables and performing construction/destruction.
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"""
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class B2(m.A2):
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def __init__(self):
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super(B2, self).__init__()
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def f(self):
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print("In python B2.f()")
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# No python subclass version
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with capture:
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a2 = m.A2()
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m.call_f(a2)
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del a2
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pytest.gc_collect()
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a3 = m.A2(1)
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m.call_f(a3)
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del a3
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pytest.gc_collect()
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assert capture == """
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PyA2.PyA2()
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PyA2.f()
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A2.f()
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PyA2.~PyA2()
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PyA2.PyA2()
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PyA2.f()
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A2.f()
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PyA2.~PyA2()
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"""
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# Python subclass version
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with capture:
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b2 = B2()
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m.call_f(b2)
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del b2
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pytest.gc_collect()
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assert capture == """
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PyA2.PyA2()
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PyA2.f()
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In python B2.f()
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PyA2.~PyA2()
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"""
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# PyPy: Reference count > 1 causes call with noncopyable instance
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# to fail in ncv1.print_nc()
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@pytest.unsupported_on_pypy
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@pytest.mark.skipif(not hasattr(m, "NCVirt"), reason="NCVirt test broken on ICPC")
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def test_move_support():
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class NCVirtExt(m.NCVirt):
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def get_noncopyable(self, a, b):
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# Constructs and returns a new instance:
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nc = m.NonCopyable(a * a, b * b)
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return nc
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def get_movable(self, a, b):
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# Return a referenced copy
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self.movable = m.Movable(a, b)
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return self.movable
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class NCVirtExt2(m.NCVirt):
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def get_noncopyable(self, a, b):
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# Keep a reference: this is going to throw an exception
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self.nc = m.NonCopyable(a, b)
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return self.nc
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def get_movable(self, a, b):
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# Return a new instance without storing it
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return m.Movable(a, b)
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ncv1 = NCVirtExt()
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assert ncv1.print_nc(2, 3) == "36"
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assert ncv1.print_movable(4, 5) == "9"
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ncv2 = NCVirtExt2()
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assert ncv2.print_movable(7, 7) == "14"
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# Don't check the exception message here because it differs under debug/non-debug mode
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with pytest.raises(RuntimeError):
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ncv2.print_nc(9, 9)
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nc_stats = ConstructorStats.get(m.NonCopyable)
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mv_stats = ConstructorStats.get(m.Movable)
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assert nc_stats.alive() == 1
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assert mv_stats.alive() == 1
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del ncv1, ncv2
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assert nc_stats.alive() == 0
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assert mv_stats.alive() == 0
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assert nc_stats.values() == ['4', '9', '9', '9']
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assert mv_stats.values() == ['4', '5', '7', '7']
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assert nc_stats.copy_constructions == 0
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assert mv_stats.copy_constructions == 1
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assert nc_stats.move_constructions >= 0
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assert mv_stats.move_constructions >= 0
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def test_dispatch_issue(msg):
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"""#159: virtual function dispatch has problems with similar-named functions"""
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class PyClass1(m.DispatchIssue):
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def dispatch(self):
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return "Yay.."
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class PyClass2(m.DispatchIssue):
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def dispatch(self):
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with pytest.raises(RuntimeError) as excinfo:
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super(PyClass2, self).dispatch()
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assert msg(excinfo.value) == 'Tried to call pure virtual function "Base::dispatch"'
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p = PyClass1()
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return m.dispatch_issue_go(p)
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b = PyClass2()
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assert m.dispatch_issue_go(b) == "Yay.."
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def test_override_ref():
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"""#392/397: overridding reference-returning functions"""
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o = m.OverrideTest("asdf")
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# Not allowed (see associated .cpp comment)
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# i = o.str_ref()
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# assert o.str_ref() == "asdf"
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assert o.str_value() == "asdf"
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assert o.A_value().value == "hi"
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a = o.A_ref()
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assert a.value == "hi"
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a.value = "bye"
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assert a.value == "bye"
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def test_inherited_virtuals():
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class AR(m.A_Repeat):
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def unlucky_number(self):
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return 99
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class AT(m.A_Tpl):
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def unlucky_number(self):
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return 999
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obj = AR()
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assert obj.say_something(3) == "hihihi"
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assert obj.unlucky_number() == 99
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assert obj.say_everything() == "hi 99"
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obj = AT()
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assert obj.say_something(3) == "hihihi"
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assert obj.unlucky_number() == 999
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assert obj.say_everything() == "hi 999"
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for obj in [m.B_Repeat(), m.B_Tpl()]:
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assert obj.say_something(3) == "B says hi 3 times"
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assert obj.unlucky_number() == 13
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assert obj.lucky_number() == 7.0
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assert obj.say_everything() == "B says hi 1 times 13"
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for obj in [m.C_Repeat(), m.C_Tpl()]:
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assert obj.say_something(3) == "B says hi 3 times"
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assert obj.unlucky_number() == 4444
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assert obj.lucky_number() == 888.0
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assert obj.say_everything() == "B says hi 1 times 4444"
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class CR(m.C_Repeat):
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def lucky_number(self):
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return m.C_Repeat.lucky_number(self) + 1.25
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obj = CR()
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assert obj.say_something(3) == "B says hi 3 times"
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assert obj.unlucky_number() == 4444
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assert obj.lucky_number() == 889.25
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assert obj.say_everything() == "B says hi 1 times 4444"
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class CT(m.C_Tpl):
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pass
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obj = CT()
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assert obj.say_something(3) == "B says hi 3 times"
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assert obj.unlucky_number() == 4444
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assert obj.lucky_number() == 888.0
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assert obj.say_everything() == "B says hi 1 times 4444"
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class CCR(CR):
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def lucky_number(self):
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return CR.lucky_number(self) * 10
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obj = CCR()
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assert obj.say_something(3) == "B says hi 3 times"
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assert obj.unlucky_number() == 4444
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assert obj.lucky_number() == 8892.5
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assert obj.say_everything() == "B says hi 1 times 4444"
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class CCT(CT):
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def lucky_number(self):
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return CT.lucky_number(self) * 1000
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obj = CCT()
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assert obj.say_something(3) == "B says hi 3 times"
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assert obj.unlucky_number() == 4444
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assert obj.lucky_number() == 888000.0
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assert obj.say_everything() == "B says hi 1 times 4444"
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class DR(m.D_Repeat):
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def unlucky_number(self):
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return 123
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def lucky_number(self):
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return 42.0
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for obj in [m.D_Repeat(), m.D_Tpl()]:
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assert obj.say_something(3) == "B says hi 3 times"
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assert obj.unlucky_number() == 4444
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assert obj.lucky_number() == 888.0
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assert obj.say_everything() == "B says hi 1 times 4444"
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obj = DR()
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assert obj.say_something(3) == "B says hi 3 times"
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assert obj.unlucky_number() == 123
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assert obj.lucky_number() == 42.0
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assert obj.say_everything() == "B says hi 1 times 123"
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class DT(m.D_Tpl):
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def say_something(self, times):
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return "DT says:" + (' quack' * times)
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def unlucky_number(self):
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return 1234
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def lucky_number(self):
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return -4.25
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obj = DT()
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assert obj.say_something(3) == "DT says: quack quack quack"
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assert obj.unlucky_number() == 1234
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assert obj.lucky_number() == -4.25
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assert obj.say_everything() == "DT says: quack 1234"
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class DT2(DT):
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def say_something(self, times):
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return "DT2: " + ('QUACK' * times)
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def unlucky_number(self):
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return -3
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class BT(m.B_Tpl):
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def say_something(self, times):
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return "BT" * times
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def unlucky_number(self):
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return -7
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def lucky_number(self):
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return -1.375
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obj = BT()
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assert obj.say_something(3) == "BTBTBT"
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assert obj.unlucky_number() == -7
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assert obj.lucky_number() == -1.375
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assert obj.say_everything() == "BT -7"
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