1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979
// Copyright (c) 2017-present PyO3 Project and Contributors
use crate::conversion::{PyTryFrom, ToBorrowedObject};
use crate::err::{self, PyDowncastError, PyErr, PyResult};
use crate::gil;
use crate::pycell::{PyBorrowError, PyBorrowMutError, PyCell};
use crate::types::{PyDict, PyTuple};
use crate::{
ffi, AsPyPointer, FromPyObject, IntoPy, IntoPyPointer, PyAny, PyClass, PyClassInitializer,
PyRef, PyRefMut, PyTypeInfo, Python, ToPyObject,
};
use std::marker::PhantomData;
use std::mem;
use std::ptr::NonNull;
/// Types that are built into the Python interpreter.
///
/// PyO3 is designed in a way that all references to those types are bound
/// to the GIL, which is why you can get a token from all references of those
/// types.
///
/// # Safety
///
/// This trait must only be implemented for types which cannot be accessed without the GIL.
pub unsafe trait PyNativeType: Sized {
/// Returns a GIL marker constrained to the lifetime of this type.
#[inline]
fn py(&self) -> Python {
unsafe { Python::assume_gil_acquired() }
}
/// Cast `&PyAny` to `&Self` without no type checking.
///
/// # Safety
///
/// `obj` must have the same layout as `*const ffi::PyObject` and must be
/// an instance of a type corresponding to `Self`.
unsafe fn unchecked_downcast(obj: &PyAny) -> &Self {
&*(obj.as_ptr() as *const Self)
}
}
/// A GIL-independent reference to an object allocated on the Python heap.
///
/// This type does not auto-dereference to the inner object because you must prove you hold the GIL to access it.
/// Instead, call one of its methods to access the inner object:
/// - [`Py::as_ref`], to borrow a GIL-bound reference to the contained object.
/// - [`Py::borrow`], [`Py::try_borrow`], [`Py::borrow_mut`], or [`Py::try_borrow_mut`],
/// to get a (mutable) reference to a contained pyclass, using a scheme similar to std's [`RefCell`].
/// See the [`PyCell` guide entry](https://pyo3.rs/latest/class.html#pycell-and-interior-mutability)
/// for more information.
/// - You can call methods directly on `Py` with [`Py::call`], [`Py::call_method`] and friends.
/// These require passing in the [`Python<'py>`](crate::Python) token but are otherwise similar to the corresponding
/// methods on [`PyAny`].
///
/// # Example: Storing Python objects in structs
///
/// As all the native Python objects only appear as references, storing them in structs doesn't work well.
/// For example, this won't compile:
///
/// ```compile_fail
/// # use pyo3::prelude::*;
/// # use pyo3::types::PyDict;
/// #
/// #[pyclass]
/// struct Foo<'py> {
/// inner: &'py PyDict,
/// }
///
/// impl Foo {
/// fn new() -> Foo {
/// let foo = Python::with_gil(|py| {
/// // `py` will only last for this scope.
///
/// // `&PyDict` derives its lifetime from `py` and
/// // so won't be able to outlive this closure.
/// let dict: &PyDict = PyDict::new(py);
///
/// // because `Foo` contains `dict` its lifetime
/// // is now also tied to `py`.
/// Foo { inner: dict }
/// });
/// // Foo is no longer valid.
/// // Returning it from this function is a 💥 compiler error 💥
/// foo
/// }
/// }
/// ```
///
/// [`Py`]`<T>` can be used to get around this by converting `dict` into a GIL-independent reference:
///
/// ```rust
/// use pyo3::prelude::*;
/// use pyo3::types::PyDict;
///
/// #[pyclass]
/// struct Foo {
/// inner: Py<PyDict>,
/// }
///
/// #[pymethods]
/// impl Foo {
/// #[new]
/// fn __new__() -> Foo {
/// Python::with_gil(|py| {
/// let dict: Py<PyDict> = PyDict::new(py).into();
/// Foo { inner: dict }
/// })
/// }
/// }
/// #
/// # fn main() -> PyResult<()> {
/// # Python::with_gil(|py| {
/// # let m = pyo3::types::PyModule::new(py, "test")?;
/// # m.add_class::<Foo>()?;
/// #
/// # let foo: &PyCell<Foo> = pyo3::PyTryFrom::try_from(m.getattr("Foo")?.call0()?)?;
/// # let dict = &foo.borrow().inner;
/// # let dict: &PyDict = dict.as_ref(py);
/// #
/// # Ok(())
/// # })
/// # }
/// ```
///
/// This can also be done with other pyclasses:
/// ```rust
/// use pyo3::prelude::*;
///
/// #[pyclass]
/// struct Bar {/* ... */}
///
/// #[pyclass]
/// struct Foo {
/// inner: Py<Bar>,
/// }
///
/// #[pymethods]
/// impl Foo {
/// #[new]
/// fn __new__() -> PyResult<Foo> {
/// Python::with_gil(|py| {
/// let bar: Py<Bar> = Py::new(py, Bar {})?;
/// Ok(Foo { inner: bar })
/// })
/// }
/// }
/// #
/// # fn main() -> PyResult<()> {
/// # Python::with_gil(|py| {
/// # let m = pyo3::types::PyModule::new(py, "test")?;
/// # m.add_class::<Foo>()?;
/// #
/// # let foo: &PyCell<Foo> = pyo3::PyTryFrom::try_from(m.getattr("Foo")?.call0()?)?;
/// # let bar = &foo.borrow().inner;
/// # let bar: &Bar = &*bar.borrow(py);
/// #
/// # Ok(())
/// # })
/// # }
/// ```
///
/// # Example: Shared ownership of Python objects
///
/// `Py<T>` can be used to share ownership of a Python object, similar to std's [`Rc`]`<T>`.
/// As with [`Rc`]`<T>`, cloning it increases its reference count rather than duplicating
/// the underlying object.
///
/// This can be done using either [`Py::clone_ref`] or [`Py`]`<T>`'s [`Clone`] trait implementation.
/// [`Py::clone_ref`] will be faster if you happen to be already holding the GIL.
///
/// ```rust
/// use pyo3::conversion::AsPyPointer;
/// use pyo3::prelude::*;
/// use pyo3::types::PyDict;
///
/// # fn main() {
/// Python::with_gil(|py| {
/// let first: Py<PyDict> = PyDict::new(py).into();
///
/// // All of these are valid syntax
/// let second = Py::clone_ref(&first, py);
/// let third = first.clone_ref(py);
/// let fourth = Py::clone(&first);
/// let fifth = first.clone();
///
/// // Disposing of our original `Py<PyDict>` just decrements the reference count.
/// drop(first);
///
/// // They all point to the same object
/// assert_eq!(second.as_ptr(), third.as_ptr());
/// assert_eq!(fourth.as_ptr(), fifth.as_ptr());
/// assert_eq!(second.as_ptr(), fourth.as_ptr());
/// });
/// # }
/// ```
///
/// # Preventing reference cycles
///
/// It is easy to accidentally create reference cycles using [`Py`]`<T>`.
/// The Python interpreter can break these reference cycles within pyclasses if they
/// implement the [`PyGCProtocol`](crate::class::gc::PyGCProtocol). If your pyclass
/// contains other Python objects you should implement this protocol to avoid leaking memory.
///
/// # A note on Python reference counts
///
/// Dropping a [`Py`]`<T>` will eventually decrease Python's reference count
/// of the pointed-to variable, allowing Python's garbage collector to free
/// the associated memory, but this may not happen immediately. This is
/// because a [`Py`]`<T>` can be dropped at any time, but the Python reference
/// count can only be modified when the GIL is held.
///
/// If a [`Py`]`<T>` is dropped while its thread happens to be holding the
/// GIL then the Python reference count will be decreased immediately.
/// Otherwise, the reference count will be decreased the next time the GIL is
/// reacquired.
///
/// # A note on `Send` and `Sync`
///
/// Accessing this object is threadsafe, since any access to its API requires a [`Python<'py>`](crate::Python) token.
/// As you can only get this by acquiring the GIL, `Py<...>` "implements [`Send`] and [`Sync`].
///
/// [`Rc`]: std::rc::Rc
/// [`RefCell`]: std::cell::RefCell
#[repr(transparent)]
pub struct Py<T>(NonNull<ffi::PyObject>, PhantomData<T>);
// The inner value is only accessed through ways that require proving the gil is held
#[cfg(feature = "nightly")]
unsafe impl<T> crate::marker::Ungil for Py<T> {}
unsafe impl<T> Send for Py<T> {}
unsafe impl<T> Sync for Py<T> {}
impl<T> Py<T>
where
T: PyClass,
{
/// Creates a new instance `Py<T>` of a `#[pyclass]` on the Python heap.
///
/// # Examples
///
/// ```rust
/// use pyo3::prelude::*;
///
/// #[pyclass]
/// struct Foo {/* fields omitted */}
///
/// # fn main() -> PyResult<()> {
/// Python::with_gil(|py| -> PyResult<Py<Foo>> {
/// let foo: Py<Foo> = Py::new(py, Foo {})?;
/// Ok(foo)
/// })?;
/// # Ok(())
/// # }
/// ```
pub fn new(py: Python, value: impl Into<PyClassInitializer<T>>) -> PyResult<Py<T>> {
let initializer = value.into();
let obj = initializer.create_cell(py)?;
let ob = unsafe { Py::from_owned_ptr(py, obj as _) };
Ok(ob)
}
}
impl<T> Py<T>
where
T: PyTypeInfo,
{
/// Borrows a GIL-bound reference to the contained `T`.
///
/// By binding to the GIL lifetime, this allows the GIL-bound reference to not require
/// [`Python<'py>`](crate::Python) for any of its methods, which makes calling methods
/// on it more ergonomic.
///
/// For native types, this reference is `&T`. For pyclasses, this is `&PyCell<T>`.
///
/// Note that the lifetime of the returned reference is the shortest of `&self` and
/// [`Python<'py>`](crate::Python).
/// Consider using [`Py::into_ref`] instead if this poses a problem.
///
/// # Examples
///
/// Get access to `&PyList` from `Py<PyList>`:
///
/// ```
/// # use pyo3::prelude::*;
/// # use pyo3::types::PyList;
/// #
/// Python::with_gil(|py| {
/// let list: Py<PyList> = PyList::empty(py).into();
/// let list: &PyList = list.as_ref(py);
/// assert_eq!(list.len(), 0);
/// });
/// ```
///
/// Get access to `&PyCell<MyClass>` from `Py<MyClass>`:
///
/// ```
/// # use pyo3::prelude::*;
/// #
/// #[pyclass]
/// struct MyClass {}
///
/// Python::with_gil(|py| {
/// let my_class: Py<MyClass> = Py::new(py, MyClass {}).unwrap();
/// let my_class_cell: &PyCell<MyClass> = my_class.as_ref(py);
/// assert!(my_class_cell.try_borrow().is_ok());
/// });
/// ```
pub fn as_ref<'py>(&'py self, _py: Python<'py>) -> &'py T::AsRefTarget {
let any = self.as_ptr() as *const PyAny;
unsafe { PyNativeType::unchecked_downcast(&*any) }
}
/// Borrows a GIL-bound reference to the contained `T` independently of the lifetime of `T`.
///
/// This method is similar to [`as_ref`](#method.as_ref) but consumes `self` and registers the
/// Python object reference in PyO3's object storage. The reference count for the Python
/// object will not be decreased until the GIL lifetime ends.
///
/// You should prefer using [`as_ref`](#method.as_ref) if you can as it'll have less overhead.
///
/// # Examples
///
/// [`Py::as_ref`]'s lifetime limitation forbids creating a function that references a
/// variable created inside the function.
///
/// ```rust,compile_fail
/// # use pyo3::prelude::*;
/// #
/// fn new_py_any<'py>(py: Python<'py>, value: impl IntoPy<Py<PyAny>>) -> &'py PyAny {
/// let obj: Py<PyAny> = value.into_py(py);
///
/// // The lifetime of the return value of this function is the shortest
/// // of `obj` and `py`. As `obj` is owned by the current function,
/// // Rust won't let the return value escape this function!
/// obj.as_ref(py)
/// }
/// ```
///
/// This can be solved by using [`Py::into_ref`] instead, which does not suffer from this issue.
/// Note that the lifetime of the [`Python<'py>`](crate::Python) token is transferred to
/// the returned reference.
///
/// ```rust
/// # use pyo3::prelude::*;
/// # #[allow(dead_code)] // This is just to show it compiles.
/// fn new_py_any<'py>(py: Python<'py>, value: impl IntoPy<Py<PyAny>>) -> &'py PyAny {
/// let obj: Py<PyAny> = value.into_py(py);
///
/// // This reference's lifetime is determined by `py`'s lifetime.
/// // Because that originates from outside this function,
/// // this return value is allowed.
/// obj.into_ref(py)
/// }
/// ```
pub fn into_ref(self, py: Python) -> &T::AsRefTarget {
unsafe { py.from_owned_ptr(self.into_ptr()) }
}
}
impl<T> Py<T>
where
T: PyClass,
{
/// Immutably borrows the value `T`.
///
/// This borrow lasts while the returned [`PyRef`] exists.
/// Multiple immutable borrows can be taken out at the same time.
///
/// Equivalent to `self.as_ref(py).borrow()` -
/// see [`PyCell::borrow`](crate::pycell::PyCell::borrow).
///
/// # Examples
///
/// ```rust
/// # use pyo3::prelude::*;
/// #
/// #[pyclass]
/// struct Foo {
/// inner: u8,
/// }
///
/// # fn main() -> PyResult<()> {
/// Python::with_gil(|py| -> PyResult<()> {
/// let foo: Py<Foo> = Py::new(py, Foo { inner: 73 })?;
/// let inner: &u8 = &foo.borrow(py).inner;
///
/// assert_eq!(*inner, 73);
/// Ok(())
/// })?;
/// # Ok(())
/// # }
/// ```
///
/// # Panics
///
/// Panics if the value is currently mutably borrowed. For a non-panicking variant, use
/// [`try_borrow`](#method.try_borrow).
pub fn borrow<'py>(&'py self, py: Python<'py>) -> PyRef<'py, T> {
self.as_ref(py).borrow()
}
/// Mutably borrows the value `T`.
///
/// This borrow lasts while the returned [`PyRefMut`] exists.
///
/// Equivalent to `self.as_ref(py).borrow_mut()` -
/// see [`PyCell::borrow_mut`](crate::pycell::PyCell::borrow_mut).
///
/// # Examples
///
/// ```
/// # use pyo3::prelude::*;
/// #
/// #[pyclass]
/// struct Foo {
/// inner: u8,
/// }
///
/// # fn main() -> PyResult<()> {
/// Python::with_gil(|py| -> PyResult<()> {
/// let foo: Py<Foo> = Py::new(py, Foo { inner: 73 })?;
/// foo.borrow_mut(py).inner = 35;
///
/// assert_eq!(foo.borrow(py).inner, 35);
/// Ok(())
/// })?;
/// # Ok(())
/// # }
/// ```
///
/// # Panics
/// Panics if the value is currently mutably borrowed. For a non-panicking variant, use
/// [`try_borrow_mut`](#method.try_borrow_mut).
pub fn borrow_mut<'py>(&'py self, py: Python<'py>) -> PyRefMut<'py, T> {
self.as_ref(py).borrow_mut()
}
/// Attempts to immutably borrow the value `T`, returning an error if the value is currently mutably borrowed.
///
/// The borrow lasts while the returned [`PyRef`] exists.
///
/// This is the non-panicking variant of [`borrow`](#method.borrow).
///
/// Equivalent to `self.as_ref(py).borrow_mut()` -
/// see [`PyCell::try_borrow`](crate::pycell::PyCell::try_borrow).
pub fn try_borrow<'py>(&'py self, py: Python<'py>) -> Result<PyRef<'py, T>, PyBorrowError> {
self.as_ref(py).try_borrow()
}
/// Attempts to mutably borrow the value `T`, returning an error if the value is currently borrowed.
///
/// The borrow lasts while the returned [`PyRefMut`] exists.
///
/// This is the non-panicking variant of [`borrow_mut`](#method.borrow_mut).
///
/// Equivalent to `self.as_ref(py).try_borrow_mut()` -
/// see [`PyCell::try_borrow_mut`](crate::pycell::PyCell::try_borrow_mut).
pub fn try_borrow_mut<'py>(
&'py self,
py: Python<'py>,
) -> Result<PyRefMut<'py, T>, PyBorrowMutError> {
self.as_ref(py).try_borrow_mut()
}
}
impl<T> Py<T> {
/// Returns whether `self` and `other` point to the same object. To compare
/// the equality of two objects (the `==` operator), use [`eq`](PyAny::eq).
///
/// This is equivalent to the Python expression `self is other`.
#[inline]
pub fn is<U: AsPyPointer>(&self, o: &U) -> bool {
self.as_ptr() == o.as_ptr()
}
/// Gets the reference count of the `ffi::PyObject` pointer.
#[inline]
pub fn get_refcnt(&self, _py: Python) -> isize {
unsafe { ffi::Py_REFCNT(self.0.as_ptr()) }
}
/// Makes a clone of `self`.
///
/// This creates another pointer to the same object, increasing its reference count.
///
/// You should prefer using this method over [`Clone`] if you happen to be holding the GIL already.
///
/// # Examples
///
/// ```rust
/// use pyo3::conversion::AsPyPointer;
/// use pyo3::prelude::*;
/// use pyo3::types::PyDict;
///
/// # fn main() {
/// Python::with_gil(|py| {
/// let first: Py<PyDict> = PyDict::new(py).into();
/// let second = Py::clone_ref(&first, py);
///
/// // Both point to the same object
/// assert_eq!(first.as_ptr(), second.as_ptr());
/// });
/// # }
/// ```
#[inline]
pub fn clone_ref(&self, py: Python) -> Py<T> {
unsafe { Py::from_borrowed_ptr(py, self.0.as_ptr()) }
}
/// Returns whether the object is considered to be None.
///
/// This is equivalent to the Python expression `self is None`.
pub fn is_none(&self, _py: Python) -> bool {
unsafe { ffi::Py_None() == self.as_ptr() }
}
/// Returns whether the object is considered to be true.
///
/// This is equivalent to the Python expression `bool(self)`.
pub fn is_true(&self, py: Python) -> PyResult<bool> {
let v = unsafe { ffi::PyObject_IsTrue(self.as_ptr()) };
err::error_on_minusone(py, v)?;
Ok(v != 0)
}
/// Extracts some type from the Python object.
///
/// This is a wrapper function around `FromPyObject::extract()`.
pub fn extract<'p, D>(&'p self, py: Python<'p>) -> PyResult<D>
where
D: FromPyObject<'p>,
{
FromPyObject::extract(unsafe { py.from_borrowed_ptr(self.as_ptr()) })
}
/// Retrieves an attribute value.
///
/// This is equivalent to the Python expression `self.attr_name`.
pub fn getattr<N>(&self, py: Python, attr_name: N) -> PyResult<PyObject>
where
N: ToPyObject,
{
attr_name.with_borrowed_ptr(py, |attr_name| unsafe {
PyObject::from_owned_ptr_or_err(py, ffi::PyObject_GetAttr(self.as_ptr(), attr_name))
})
}
/// Sets an attribute value.
///
/// This is equivalent to the Python expression `self.attr_name = value`.
pub fn setattr<N, V>(&self, py: Python, attr_name: N, value: V) -> PyResult<()>
where
N: ToPyObject,
V: ToPyObject,
{
attr_name.with_borrowed_ptr(py, move |attr_name| {
value.with_borrowed_ptr(py, |value| unsafe {
err::error_on_minusone(py, ffi::PyObject_SetAttr(self.as_ptr(), attr_name, value))
})
})
}
/// Calls the object.
///
/// This is equivalent to the Python expression `self(*args, **kwargs)`.
pub fn call(
&self,
py: Python,
args: impl IntoPy<Py<PyTuple>>,
kwargs: Option<&PyDict>,
) -> PyResult<PyObject> {
let args = args.into_py(py).into_ptr();
let kwargs = kwargs.into_ptr();
let result = unsafe {
PyObject::from_owned_ptr_or_err(py, ffi::PyObject_Call(self.as_ptr(), args, kwargs))
};
unsafe {
ffi::Py_XDECREF(args);
ffi::Py_XDECREF(kwargs);
}
result
}
/// Calls the object with only positional arguments.
///
/// This is equivalent to the Python expression `self(*args)`.
pub fn call1(&self, py: Python, args: impl IntoPy<Py<PyTuple>>) -> PyResult<PyObject> {
self.call(py, args, None)
}
/// Calls the object without arguments.
///
/// This is equivalent to the Python expression `self()`.
pub fn call0(&self, py: Python) -> PyResult<PyObject> {
cfg_if::cfg_if! {
if #[cfg(all(Py_3_9, not(PyPy)))] {
// Optimized path on python 3.9+
unsafe {
PyObject::from_owned_ptr_or_err(py, ffi::PyObject_CallNoArgs(self.as_ptr()))
}
} else {
self.call(py, (), None)
}
}
}
/// Calls a method on the object.
///
/// This is equivalent to the Python expression `self.name(*args, **kwargs)`.
pub fn call_method(
&self,
py: Python,
name: &str,
args: impl IntoPy<Py<PyTuple>>,
kwargs: Option<&PyDict>,
) -> PyResult<PyObject> {
name.with_borrowed_ptr(py, |name| unsafe {
let args = args.into_py(py).into_ptr();
let kwargs = kwargs.into_ptr();
let ptr = ffi::PyObject_GetAttr(self.as_ptr(), name);
if ptr.is_null() {
return Err(PyErr::fetch(py));
}
let result = PyObject::from_owned_ptr_or_err(py, ffi::PyObject_Call(ptr, args, kwargs));
ffi::Py_DECREF(ptr);
ffi::Py_XDECREF(args);
ffi::Py_XDECREF(kwargs);
result
})
}
/// Calls a method on the object with only positional arguments.
///
/// This is equivalent to the Python expression `self.name(*args)`.
pub fn call_method1(
&self,
py: Python,
name: &str,
args: impl IntoPy<Py<PyTuple>>,
) -> PyResult<PyObject> {
self.call_method(py, name, args, None)
}
/// Calls a method on the object with no arguments.
///
/// This is equivalent to the Python expression `self.name()`.
pub fn call_method0(&self, py: Python, name: &str) -> PyResult<PyObject> {
cfg_if::cfg_if! {
if #[cfg(all(Py_3_9, not(any(Py_LIMITED_API, PyPy))))] {
// Optimized path on python 3.9+
unsafe {
let name = name.into_py(py);
PyObject::from_owned_ptr_or_err(py, ffi::PyObject_CallMethodNoArgs(self.as_ptr(), name.as_ptr()))
}
} else {
self.call_method(py, name, (), None)
}
}
}
/// Create a `Py<T>` instance by taking ownership of the given FFI pointer.
///
/// # Safety
/// `ptr` must be a pointer to a Python object of type T.
///
/// Callers must own the object referred to by `ptr`, as this function
/// implicitly takes ownership of that object.
///
/// # Panics
/// Panics if `ptr` is null.
#[inline]
pub unsafe fn from_owned_ptr(py: Python, ptr: *mut ffi::PyObject) -> Py<T> {
match NonNull::new(ptr) {
Some(nonnull_ptr) => Py(nonnull_ptr, PhantomData),
None => crate::err::panic_after_error(py),
}
}
/// Create a `Py<T>` instance by taking ownership of the given FFI pointer.
///
/// If `ptr` is null then the current Python exception is fetched as a `PyErr`.
///
/// # Safety
/// If non-null, `ptr` must be a pointer to a Python object of type T.
#[inline]
pub unsafe fn from_owned_ptr_or_err(py: Python, ptr: *mut ffi::PyObject) -> PyResult<Py<T>> {
match NonNull::new(ptr) {
Some(nonnull_ptr) => Ok(Py(nonnull_ptr, PhantomData)),
None => Err(PyErr::fetch(py)),
}
}
/// Create a `Py<T>` instance by taking ownership of the given FFI pointer.
///
/// If `ptr` is null then `None` is returned.
///
/// # Safety
/// If non-null, `ptr` must be a pointer to a Python object of type T.
#[inline]
pub unsafe fn from_owned_ptr_or_opt(_py: Python, ptr: *mut ffi::PyObject) -> Option<Self> {
NonNull::new(ptr).map(|nonnull_ptr| Py(nonnull_ptr, PhantomData))
}
/// Create a `Py<T>` instance by creating a new reference from the given FFI pointer.
///
/// # Safety
/// `ptr` must be a pointer to a Python object of type T.
///
/// # Panics
/// Panics if `ptr` is null.
#[inline]
pub unsafe fn from_borrowed_ptr(py: Python, ptr: *mut ffi::PyObject) -> Py<T> {
match Self::from_borrowed_ptr_or_opt(py, ptr) {
Some(slf) => slf,
None => crate::err::panic_after_error(py),
}
}
/// Create a `Py<T>` instance by creating a new reference from the given FFI pointer.
///
/// If `ptr` is null then the current Python exception is fetched as a `PyErr`.
///
/// # Safety
/// `ptr` must be a pointer to a Python object of type T.
#[inline]
pub unsafe fn from_borrowed_ptr_or_err(py: Python, ptr: *mut ffi::PyObject) -> PyResult<Self> {
Self::from_borrowed_ptr_or_opt(py, ptr).ok_or_else(|| PyErr::fetch(py))
}
/// Create a `Py<T>` instance by creating a new reference from the given FFI pointer.
///
/// If `ptr` is null then `None` is returned.
///
/// # Safety
/// `ptr` must be a pointer to a Python object of type T.
#[inline]
pub unsafe fn from_borrowed_ptr_or_opt(_py: Python, ptr: *mut ffi::PyObject) -> Option<Self> {
NonNull::new(ptr).map(|nonnull_ptr| {
ffi::Py_INCREF(ptr);
Py(nonnull_ptr, PhantomData)
})
}
/// For internal conversions.
///
/// # Safety
/// `ptr` must point to a Python object of type T.
#[inline]
unsafe fn from_non_null(ptr: NonNull<ffi::PyObject>) -> Self {
Self(ptr, PhantomData)
}
/// Returns the inner pointer without decreasing the refcount.
#[inline]
fn into_non_null(self) -> NonNull<ffi::PyObject> {
let pointer = self.0;
mem::forget(self);
pointer
}
}
impl<T> ToPyObject for Py<T> {
/// Converts `Py` instance -> PyObject.
fn to_object(&self, py: Python) -> PyObject {
unsafe { PyObject::from_borrowed_ptr(py, self.as_ptr()) }
}
}
impl<T> IntoPy<PyObject> for Py<T> {
/// Converts a `Py` instance to `PyObject`.
/// Consumes `self` without calling `Py_DECREF()`.
#[inline]
fn into_py(self, _py: Python) -> PyObject {
unsafe { PyObject::from_non_null(self.into_non_null()) }
}
}
impl<T> AsPyPointer for Py<T> {
/// Gets the underlying FFI pointer, returns a borrowed pointer.
#[inline]
fn as_ptr(&self) -> *mut ffi::PyObject {
self.0.as_ptr()
}
}
impl<T> IntoPyPointer for Py<T> {
/// Gets the underlying FFI pointer, returns a owned pointer.
#[inline]
#[must_use]
fn into_ptr(self) -> *mut ffi::PyObject {
self.into_non_null().as_ptr()
}
}
impl<T> std::convert::From<&'_ T> for PyObject
where
T: AsPyPointer + PyNativeType,
{
fn from(obj: &T) -> Self {
unsafe { Py::from_borrowed_ptr(obj.py(), obj.as_ptr()) }
}
}
impl<T> std::convert::From<Py<T>> for PyObject
where
T: AsRef<PyAny>,
{
#[inline]
fn from(other: Py<T>) -> Self {
unsafe { Self::from_non_null(other.into_non_null()) }
}
}
// `&PyCell<T>` can be converted to `Py<T>`
impl<'a, T> std::convert::From<&PyCell<T>> for Py<T>
where
T: PyClass,
{
fn from(cell: &PyCell<T>) -> Self {
unsafe { Py::from_borrowed_ptr(cell.py(), cell.as_ptr()) }
}
}
impl<'a, T> std::convert::From<PyRef<'a, T>> for Py<T>
where
T: PyClass,
{
fn from(pyref: PyRef<'a, T>) -> Self {
unsafe { Py::from_borrowed_ptr(pyref.py(), pyref.as_ptr()) }
}
}
impl<'a, T> std::convert::From<PyRefMut<'a, T>> for Py<T>
where
T: PyClass,
{
fn from(pyref: PyRefMut<'a, T>) -> Self {
unsafe { Py::from_borrowed_ptr(pyref.py(), pyref.as_ptr()) }
}
}
/// If the GIL is held this increments `self`'s reference count.
/// Otherwise this registers the [`Py`]`<T>` instance to have its reference count
/// incremented the next time PyO3 acquires the GIL.
impl<T> Clone for Py<T> {
fn clone(&self) -> Self {
unsafe {
gil::register_incref(self.0);
}
Self(self.0, PhantomData)
}
}
/// Dropping a `Py` instance decrements the reference count on the object by 1.
impl<T> Drop for Py<T> {
fn drop(&mut self) {
unsafe {
gil::register_decref(self.0);
}
}
}
impl<'a, T> FromPyObject<'a> for Py<T>
where
T: PyTypeInfo,
&'a T::AsRefTarget: FromPyObject<'a>,
T::AsRefTarget: 'a + AsPyPointer,
{
/// Extracts `Self` from the source `PyObject`.
fn extract(ob: &'a PyAny) -> PyResult<Self> {
unsafe {
ob.extract::<&T::AsRefTarget>()
.map(|val| Py::from_borrowed_ptr(ob.py(), val.as_ptr()))
}
}
}
/// Py<T> can be used as an error when T is an Error.
///
/// However for GIL lifetime reasons, cause() cannot be implemented for Py<T>.
/// Use .as_ref() to get the GIL-scoped error if you need to inspect the cause.
impl<T> std::error::Error for Py<T>
where
T: std::error::Error + PyTypeInfo,
T::AsRefTarget: std::fmt::Display,
{
}
impl<T> std::fmt::Display for Py<T>
where
T: PyTypeInfo,
T::AsRefTarget: std::fmt::Display,
{
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
Python::with_gil(|py| std::fmt::Display::fmt(self.as_ref(py), f))
}
}
impl<T> std::fmt::Debug for Py<T> {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
f.debug_tuple("Py").field(&self.0.as_ptr()).finish()
}
}
/// A commonly-used alias for `Py<PyAny>`.
///
/// This is an owned reference a Python object without any type information. This value can also be
/// safely sent between threads.
///
/// See the documentation for [`Py`](struct.Py.html).
pub type PyObject = Py<PyAny>;
impl PyObject {
/// Casts the PyObject to a concrete Python object type.
///
/// This can cast only to native Python types, not types implemented in Rust. For a more
/// flexible alternative, see [`Py::extract`](struct.Py.html#method.extract).
pub fn cast_as<'p, D>(&'p self, py: Python<'p>) -> Result<&'p D, PyDowncastError>
where
D: PyTryFrom<'p>,
{
D::try_from(unsafe { py.from_borrowed_ptr::<PyAny>(self.as_ptr()) })
}
}
#[cfg(test)]
mod tests {
use super::{Py, PyObject};
use crate::types::PyDict;
use crate::{Python, ToPyObject};
#[test]
fn test_call0() {
Python::with_gil(|py| {
let obj = py.get_type::<PyDict>().to_object(py);
assert_eq!(
obj.call0(py)
.unwrap()
.as_ref(py)
.repr()
.unwrap()
.to_string_lossy(),
"{}"
);
})
}
#[test]
fn test_call_for_non_existing_method() {
Python::with_gil(|py| {
let obj: PyObject = PyDict::new(py).into();
assert!(obj.call_method0(py, "asdf").is_err());
assert!(obj
.call_method(py, "nonexistent_method", (1,), None)
.is_err());
assert!(obj.call_method0(py, "nonexistent_method").is_err());
assert!(obj.call_method1(py, "nonexistent_method", (1,)).is_err());
});
}
#[test]
fn py_from_dict() {
let dict: Py<PyDict> = Python::with_gil(|py| {
let native = PyDict::new(py);
Py::from(native)
});
assert_eq!(Python::with_gil(|py| dict.get_refcnt(py)), 1);
}
#[test]
fn pyobject_from_py() {
Python::with_gil(|py| {
let dict: Py<PyDict> = PyDict::new(py).into();
let cnt = dict.get_refcnt(py);
let p: PyObject = dict.into();
assert_eq!(p.get_refcnt(py), cnt);
});
}
}