pub struct PyCapsule(/* private fields */);Expand description
Represents a Python Capsule as described in Capsules:
This subtype of PyObject represents an opaque value, useful for C extension modules who need to pass an opaque value (as a void* pointer) through Python code to other C code. It is often used to make a C function pointer defined in one module available to other modules, so the regular import mechanism can be used to access C APIs defined in dynamically loaded modules.
Values of this type are accessed via PyO3’s smart pointers, e.g. as
Py<PyCapsule> or Bound<'py, PyCapsule>.
For APIs available on capsule objects, see the PyCapsuleMethods trait which is implemented for
Bound<'py, PyCapsule>.
§Example
use pyo3::{prelude::*, types::PyCapsule};
use std::ffi::CString;
#[repr(C)]
struct Foo {
pub val: u32,
}
let r = Python::with_gil(|py| -> PyResult<()> {
let foo = Foo { val: 123 };
let name = CString::new("builtins.capsule").unwrap();
let capsule = PyCapsule::new_bound(py, foo, Some(name.clone()))?;
let module = PyModule::import_bound(py, "builtins")?;
module.add("capsule", capsule)?;
let cap: &Foo = unsafe { PyCapsule::import(py, name.as_ref())? };
assert_eq!(cap.val, 123);
Ok(())
});
assert!(r.is_ok());Implementations§
source§impl PyCapsule
impl PyCapsule
sourcepub fn new_bound<T: 'static + Send + AssertNotZeroSized>(
py: Python<'_>,
value: T,
name: Option<CString>,
) -> PyResult<Bound<'_, Self>>
pub fn new_bound<T: 'static + Send + AssertNotZeroSized>( py: Python<'_>, value: T, name: Option<CString>, ) -> PyResult<Bound<'_, Self>>
Constructs a new capsule whose contents are value, associated with name.
name is the identifier for the capsule; if it is stored as an attribute of a module,
the name should be in the format "modulename.attribute".
It is checked at compile time that the type T is not zero-sized. Rust function items
need to be cast to a function pointer (fn(args) -> result) to be put into a capsule.
§Example
use pyo3::{prelude::*, types::PyCapsule};
use std::ffi::CString;
Python::with_gil(|py| {
let name = CString::new("foo").unwrap();
let capsule = PyCapsule::new_bound(py, 123_u32, Some(name)).unwrap();
let val = unsafe { capsule.reference::<u32>() };
assert_eq!(*val, 123);
});However, attempting to construct a PyCapsule with a zero-sized type will not compile:
use pyo3::{prelude::*, types::PyCapsule};
use std::ffi::CString;
Python::with_gil(|py| {
let capsule = PyCapsule::new_bound(py, (), None).unwrap(); // Oops! `()` is zero sized!
});sourcepub fn new_bound_with_destructor<T: 'static + Send + AssertNotZeroSized, F: FnOnce(T, *mut c_void) + Send>(
py: Python<'_>,
value: T,
name: Option<CString>,
destructor: F,
) -> PyResult<Bound<'_, Self>>
pub fn new_bound_with_destructor<T: 'static + Send + AssertNotZeroSized, F: FnOnce(T, *mut c_void) + Send>( py: Python<'_>, value: T, name: Option<CString>, destructor: F, ) -> PyResult<Bound<'_, Self>>
Constructs a new capsule whose contents are value, associated with name.
Also provides a destructor: when the PyCapsule is destroyed, it will be passed the original object,
as well as a *mut c_void which will point to the capsule’s context, if any.
The destructor must be Send, because there is no guarantee which thread it will eventually
be called from.
sourcepub unsafe fn import<'py, T>(py: Python<'py>, name: &CStr) -> PyResult<&'py T>
pub unsafe fn import<'py, T>(py: Python<'py>, name: &CStr) -> PyResult<&'py T>
Imports an existing capsule.
The name should match the path to the module attribute exactly in the form
of "module.attribute", which should be the same as the name within the capsule.
§Safety
It must be known that the capsule imported by name contains an item of type T.
source§impl PyCapsule
impl PyCapsule
sourcepub fn new<T: 'static + Send + AssertNotZeroSized>(
py: Python<'_>,
value: T,
name: Option<CString>,
) -> PyResult<&Self>
👎Deprecated since 0.21.0: PyCapsule::new will be replaced by PyCapsule::new_bound in a future PyO3 versionAvailable on crate feature gil-refs only.
pub fn new<T: 'static + Send + AssertNotZeroSized>( py: Python<'_>, value: T, name: Option<CString>, ) -> PyResult<&Self>
PyCapsule::new will be replaced by PyCapsule::new_bound in a future PyO3 versiongil-refs only.Deprecated form of PyCapsule::new_bound.
sourcepub fn new_with_destructor<T: 'static + Send + AssertNotZeroSized, F: FnOnce(T, *mut c_void) + Send>(
py: Python<'_>,
value: T,
name: Option<CString>,
destructor: F,
) -> PyResult<&Self>
👎Deprecated since 0.21.0: PyCapsule::new_with_destructor will be replaced by PyCapsule::new_bound_with_destructor in a future PyO3 versionAvailable on crate feature gil-refs only.
pub fn new_with_destructor<T: 'static + Send + AssertNotZeroSized, F: FnOnce(T, *mut c_void) + Send>( py: Python<'_>, value: T, name: Option<CString>, destructor: F, ) -> PyResult<&Self>
PyCapsule::new_with_destructor will be replaced by PyCapsule::new_bound_with_destructor in a future PyO3 versiongil-refs only.Deprecated form of PyCapsule::new_bound_with_destructor.
sourcepub fn set_context(&self, context: *mut c_void) -> PyResult<()>
Available on crate feature gil-refs only.
pub fn set_context(&self, context: *mut c_void) -> PyResult<()>
gil-refs only.Sets the context pointer in the capsule.
Returns an error if this capsule is not valid.
§Notes
The context is treated much like the value of the capsule, but should likely act as a place to store any state management when using the capsule.
If you want to store a Rust value as the context, and drop it from the destructor, use
Box::into_raw to convert it into a pointer, see the example.
§Example
use std::sync::mpsc::{channel, Sender};
use libc::c_void;
use pyo3::{prelude::*, types::PyCapsule};
let (tx, rx) = channel::<String>();
fn destructor(val: u32, context: *mut c_void) {
let ctx = unsafe { *Box::from_raw(context.cast::<Sender<String>>()) };
ctx.send("Destructor called!".to_string()).unwrap();
}
Python::with_gil(|py| {
let capsule =
PyCapsule::new_bound_with_destructor(py, 123, None, destructor as fn(u32, *mut c_void))
.unwrap();
let context = Box::new(tx); // `Sender<String>` is our context, box it up and ship it!
capsule.set_context(Box::into_raw(context).cast()).unwrap();
// This scope will end, causing our destructor to be called...
});
assert_eq!(rx.recv(), Ok("Destructor called!".to_string()));sourcepub fn context(&self) -> PyResult<*mut c_void>
Available on crate feature gil-refs only.
pub fn context(&self) -> PyResult<*mut c_void>
gil-refs only.Gets the current context stored in the capsule. If there is no context, the pointer will be null.
Returns an error if this capsule is not valid.
sourcepub unsafe fn reference<T>(&self) -> &T
Available on crate feature gil-refs only.
pub unsafe fn reference<T>(&self) -> &T
gil-refs only.Obtains a reference to the value of this capsule.
§Safety
It must be known that this capsule is valid and its pointer is to an item of type T.
sourcepub fn pointer(&self) -> *mut c_void
Available on crate feature gil-refs only.
pub fn pointer(&self) -> *mut c_void
gil-refs only.Gets the raw c_void pointer to the value in this capsule.
Returns null if this capsule is not valid.
Methods from Deref<Target = PyAny>§
sourcepub fn is<T: AsPyPointer>(&self, other: &T) -> bool
Available on crate feature gil-refs only.
pub fn is<T: AsPyPointer>(&self, other: &T) -> bool
gil-refs only.Returns whether self and other point to the same object. To compare
the equality of two objects (the == operator), use eq.
This is equivalent to the Python expression self is other.
sourcepub fn hasattr<N>(&self, attr_name: N) -> PyResult<bool>
Available on crate feature gil-refs only.
pub fn hasattr<N>(&self, attr_name: N) -> PyResult<bool>
gil-refs only.Determines whether this object has the given attribute.
This is equivalent to the Python expression hasattr(self, attr_name).
To avoid repeated temporary allocations of Python strings, the intern! macro can be used
to intern attr_name.
§Example: intern!ing the attribute name
#[pyfunction]
fn has_version(sys: &Bound<'_, PyModule>) -> PyResult<bool> {
sys.hasattr(intern!(sys.py(), "version"))
}sourcepub fn getattr<N>(&self, attr_name: N) -> PyResult<&PyAny>
Available on crate feature gil-refs only.
pub fn getattr<N>(&self, attr_name: N) -> PyResult<&PyAny>
gil-refs only.Retrieves an attribute value.
This is equivalent to the Python expression self.attr_name.
To avoid repeated temporary allocations of Python strings, the intern! macro can be used
to intern attr_name.
§Example: intern!ing the attribute name
#[pyfunction]
fn version<'py>(sys: &Bound<'py, PyModule>) -> PyResult<Bound<'py, PyAny>> {
sys.getattr(intern!(sys.py(), "version"))
}sourcepub fn setattr<N, V>(&self, attr_name: N, value: V) -> PyResult<()>
Available on crate feature gil-refs only.
pub fn setattr<N, V>(&self, attr_name: N, value: V) -> PyResult<()>
gil-refs only.Sets an attribute value.
This is equivalent to the Python expression self.attr_name = value.
To avoid repeated temporary allocations of Python strings, the intern! macro can be used
to intern name.
§Example: intern!ing the attribute name
#[pyfunction]
fn set_answer(ob: &Bound<'_, PyAny>) -> PyResult<()> {
ob.setattr(intern!(ob.py(), "answer"), 42)
}sourcepub fn delattr<N>(&self, attr_name: N) -> PyResult<()>
Available on crate feature gil-refs only.
pub fn delattr<N>(&self, attr_name: N) -> PyResult<()>
gil-refs only.Deletes an attribute.
This is equivalent to the Python statement del self.attr_name.
To avoid repeated temporary allocations of Python strings, the intern! macro can be used
to intern attr_name.
sourcepub fn compare<O>(&self, other: O) -> PyResult<Ordering>where
O: ToPyObject,
Available on crate feature gil-refs only.
pub fn compare<O>(&self, other: O) -> PyResult<Ordering>where
O: ToPyObject,
gil-refs only.Returns an Ordering between self and other.
This is equivalent to the following Python code:
if self == other:
return Equal
elif a < b:
return Less
elif a > b:
return Greater
else:
raise TypeError("PyAny::compare(): All comparisons returned false")
§Examples
use pyo3::prelude::*;
use pyo3::types::PyFloat;
use std::cmp::Ordering;
Python::with_gil(|py| -> PyResult<()> {
let a = PyFloat::new_bound(py, 0_f64);
let b = PyFloat::new_bound(py, 42_f64);
assert_eq!(a.compare(b)?, Ordering::Less);
Ok(())
})?;It will return PyErr for values that cannot be compared:
use pyo3::prelude::*;
use pyo3::types::{PyFloat, PyString};
Python::with_gil(|py| -> PyResult<()> {
let a = PyFloat::new_bound(py, 0_f64);
let b = PyString::new_bound(py, "zero");
assert!(a.compare(b).is_err());
Ok(())
})?;sourcepub fn rich_compare<O>(
&self,
other: O,
compare_op: CompareOp,
) -> PyResult<&PyAny>where
O: ToPyObject,
Available on crate feature gil-refs only.
pub fn rich_compare<O>(
&self,
other: O,
compare_op: CompareOp,
) -> PyResult<&PyAny>where
O: ToPyObject,
gil-refs only.Tests whether two Python objects obey a given CompareOp.
lt, le, eq, ne,
gt and ge are the specialized versions
of this function.
Depending on the value of compare_op, this is equivalent to one of the
following Python expressions:
compare_op | Python expression |
|---|---|
CompareOp::Eq | self == other |
CompareOp::Ne | self != other |
CompareOp::Lt | self < other |
CompareOp::Le | self <= other |
CompareOp::Gt | self > other |
CompareOp::Ge | self >= other |
§Examples
use pyo3::class::basic::CompareOp;
use pyo3::prelude::*;
use pyo3::types::PyInt;
Python::with_gil(|py| -> PyResult<()> {
let a: Bound<'_, PyInt> = 0_u8.into_py(py).into_bound(py).downcast_into()?;
let b: Bound<'_, PyInt> = 42_u8.into_py(py).into_bound(py).downcast_into()?;
assert!(a.rich_compare(b, CompareOp::Le)?.is_truthy()?);
Ok(())
})?;sourcepub fn lt<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
Available on crate feature gil-refs only.
pub fn lt<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
gil-refs only.Tests whether this object is less than another.
This is equivalent to the Python expression self < other.
sourcepub fn le<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
Available on crate feature gil-refs only.
pub fn le<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
gil-refs only.Tests whether this object is less than or equal to another.
This is equivalent to the Python expression self <= other.
sourcepub fn eq<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
Available on crate feature gil-refs only.
pub fn eq<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
gil-refs only.Tests whether this object is equal to another.
This is equivalent to the Python expression self == other.
sourcepub fn ne<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
Available on crate feature gil-refs only.
pub fn ne<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
gil-refs only.Tests whether this object is not equal to another.
This is equivalent to the Python expression self != other.
sourcepub fn gt<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
Available on crate feature gil-refs only.
pub fn gt<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
gil-refs only.Tests whether this object is greater than another.
This is equivalent to the Python expression self > other.
sourcepub fn ge<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
Available on crate feature gil-refs only.
pub fn ge<O>(&self, other: O) -> PyResult<bool>where
O: ToPyObject,
gil-refs only.Tests whether this object is greater than or equal to another.
This is equivalent to the Python expression self >= other.
sourcepub fn is_callable(&self) -> bool
Available on crate feature gil-refs only.
pub fn is_callable(&self) -> bool
gil-refs only.Determines whether this object appears callable.
This is equivalent to Python’s callable() function.
§Examples
use pyo3::prelude::*;
Python::with_gil(|py| -> PyResult<()> {
let builtins = PyModule::import_bound(py, "builtins")?;
let print = builtins.getattr("print")?;
assert!(print.is_callable());
Ok(())
})?;This is equivalent to the Python statement assert callable(print).
Note that unless an API needs to distinguish between callable and non-callable objects, there is no point in checking for callability. Instead, it is better to just do the call and handle potential exceptions.
sourcepub fn call(
&self,
args: impl IntoPy<Py<PyTuple>>,
kwargs: Option<&PyDict>,
) -> PyResult<&PyAny>
Available on crate feature gil-refs only.
pub fn call( &self, args: impl IntoPy<Py<PyTuple>>, kwargs: Option<&PyDict>, ) -> PyResult<&PyAny>
gil-refs only.Calls the object.
This is equivalent to the Python expression self(*args, **kwargs).
§Examples
use pyo3::prelude::*;
use pyo3::types::PyDict;
const CODE: &str = r#"
def function(*args, **kwargs):
assert args == ("hello",)
assert kwargs == {"cruel": "world"}
return "called with args and kwargs"
"#;
Python::with_gil(|py| {
let module = PyModule::from_code_bound(py, CODE, "", "")?;
let fun = module.getattr("function")?;
let args = ("hello",);
let kwargs = PyDict::new_bound(py);
kwargs.set_item("cruel", "world")?;
let result = fun.call(args, Some(&kwargs))?;
assert_eq!(result.extract::<String>()?, "called with args and kwargs");
Ok(())
})sourcepub fn call0(&self) -> PyResult<&PyAny>
Available on crate feature gil-refs only.
pub fn call0(&self) -> PyResult<&PyAny>
gil-refs only.Calls the object without arguments.
This is equivalent to the Python expression self().
§Examples
use pyo3::prelude::*;
Python::with_gil(|py| -> PyResult<()> {
let module = PyModule::import_bound(py, "builtins")?;
let help = module.getattr("help")?;
help.call0()?;
Ok(())
})?;This is equivalent to the Python expression help().
sourcepub fn call1(&self, args: impl IntoPy<Py<PyTuple>>) -> PyResult<&PyAny>
Available on crate feature gil-refs only.
pub fn call1(&self, args: impl IntoPy<Py<PyTuple>>) -> PyResult<&PyAny>
gil-refs only.Calls the object with only positional arguments.
This is equivalent to the Python expression self(*args).
§Examples
use pyo3::prelude::*;
const CODE: &str = r#"
def function(*args, **kwargs):
assert args == ("hello",)
assert kwargs == {}
return "called with args"
"#;
Python::with_gil(|py| {
let module = PyModule::from_code_bound(py, CODE, "", "")?;
let fun = module.getattr("function")?;
let args = ("hello",);
let result = fun.call1(args)?;
assert_eq!(result.extract::<String>()?, "called with args");
Ok(())
})sourcepub fn call_method<N, A>(
&self,
name: N,
args: A,
kwargs: Option<&PyDict>,
) -> PyResult<&PyAny>
Available on crate feature gil-refs only.
pub fn call_method<N, A>( &self, name: N, args: A, kwargs: Option<&PyDict>, ) -> PyResult<&PyAny>
gil-refs only.Calls a method on the object.
This is equivalent to the Python expression self.name(*args, **kwargs).
To avoid repeated temporary allocations of Python strings, the intern! macro can be used
to intern name.
§Examples
use pyo3::prelude::*;
use pyo3::types::PyDict;
const CODE: &str = r#"
class A:
def method(self, *args, **kwargs):
assert args == ("hello",)
assert kwargs == {"cruel": "world"}
return "called with args and kwargs"
a = A()
"#;
Python::with_gil(|py| {
let module = PyModule::from_code_bound(py, CODE, "", "")?;
let instance = module.getattr("a")?;
let args = ("hello",);
let kwargs = PyDict::new_bound(py);
kwargs.set_item("cruel", "world")?;
let result = instance.call_method("method", args, Some(&kwargs))?;
assert_eq!(result.extract::<String>()?, "called with args and kwargs");
Ok(())
})sourcepub fn call_method0<N>(&self, name: N) -> PyResult<&PyAny>
Available on crate feature gil-refs only.
pub fn call_method0<N>(&self, name: N) -> PyResult<&PyAny>
gil-refs only.Calls a method on the object without arguments.
This is equivalent to the Python expression self.name().
To avoid repeated temporary allocations of Python strings, the intern! macro can be used
to intern name.
§Examples
use pyo3::prelude::*;
const CODE: &str = r#"
class A:
def method(self, *args, **kwargs):
assert args == ()
assert kwargs == {}
return "called with no arguments"
a = A()
"#;
Python::with_gil(|py| {
let module = PyModule::from_code_bound(py, CODE, "", "")?;
let instance = module.getattr("a")?;
let result = instance.call_method0("method")?;
assert_eq!(result.extract::<String>()?, "called with no arguments");
Ok(())
})sourcepub fn call_method1<N, A>(&self, name: N, args: A) -> PyResult<&PyAny>
Available on crate feature gil-refs only.
pub fn call_method1<N, A>(&self, name: N, args: A) -> PyResult<&PyAny>
gil-refs only.Calls a method on the object with only positional arguments.
This is equivalent to the Python expression self.name(*args).
To avoid repeated temporary allocations of Python strings, the intern! macro can be used
to intern name.
§Examples
use pyo3::prelude::*;
const CODE: &str = r#"
class A:
def method(self, *args, **kwargs):
assert args == ("hello",)
assert kwargs == {}
return "called with args"
a = A()
"#;
Python::with_gil(|py| {
let module = PyModule::from_code_bound(py, CODE, "", "")?;
let instance = module.getattr("a")?;
let args = ("hello",);
let result = instance.call_method1("method", args)?;
assert_eq!(result.extract::<String>()?, "called with args");
Ok(())
})sourcepub fn is_true(&self) -> PyResult<bool>
👎Deprecated since 0.21.0: use .is_truthy() insteadAvailable on crate feature gil-refs only.
pub fn is_true(&self) -> PyResult<bool>
.is_truthy() insteadgil-refs only.Returns whether the object is considered to be true.
This is equivalent to the Python expression bool(self).
sourcepub fn is_truthy(&self) -> PyResult<bool>
Available on crate feature gil-refs only.
pub fn is_truthy(&self) -> PyResult<bool>
gil-refs only.Returns whether the object is considered to be true.
This applies truth value testing equivalent to the Python expression bool(self).
sourcepub fn is_none(&self) -> bool
Available on crate feature gil-refs only.
pub fn is_none(&self) -> bool
gil-refs only.Returns whether the object is considered to be None.
This is equivalent to the Python expression self is None.
sourcepub fn is_ellipsis(&self) -> bool
👎Deprecated since 0.20.0: use .is(py.Ellipsis()) insteadAvailable on crate feature gil-refs only.
pub fn is_ellipsis(&self) -> bool
.is(py.Ellipsis()) insteadgil-refs only.Returns whether the object is Ellipsis, e.g. ....
This is equivalent to the Python expression self is ....
sourcepub fn is_empty(&self) -> PyResult<bool>
Available on crate feature gil-refs only.
pub fn is_empty(&self) -> PyResult<bool>
gil-refs only.Returns true if the sequence or mapping has a length of 0.
This is equivalent to the Python expression len(self) == 0.
sourcepub fn get_item<K>(&self, key: K) -> PyResult<&PyAny>where
K: ToPyObject,
Available on crate feature gil-refs only.
pub fn get_item<K>(&self, key: K) -> PyResult<&PyAny>where
K: ToPyObject,
gil-refs only.Gets an item from the collection.
This is equivalent to the Python expression self[key].
sourcepub fn set_item<K, V>(&self, key: K, value: V) -> PyResult<()>where
K: ToPyObject,
V: ToPyObject,
Available on crate feature gil-refs only.
pub fn set_item<K, V>(&self, key: K, value: V) -> PyResult<()>where
K: ToPyObject,
V: ToPyObject,
gil-refs only.Sets a collection item value.
This is equivalent to the Python expression self[key] = value.
sourcepub fn del_item<K>(&self, key: K) -> PyResult<()>where
K: ToPyObject,
Available on crate feature gil-refs only.
pub fn del_item<K>(&self, key: K) -> PyResult<()>where
K: ToPyObject,
gil-refs only.Deletes an item from the collection.
This is equivalent to the Python expression del self[key].
sourcepub fn iter(&self) -> PyResult<&PyIterator>
Available on crate feature gil-refs only.
pub fn iter(&self) -> PyResult<&PyIterator>
gil-refs only.Takes an object and returns an iterator for it.
This is typically a new iterator but if the argument is an iterator, this returns itself.
sourcepub fn get_type(&self) -> &PyType
Available on crate feature gil-refs only.
pub fn get_type(&self) -> &PyType
gil-refs only.Returns the Python type object for this object’s type.
sourcepub fn get_type_ptr(&self) -> *mut PyTypeObject
Available on crate feature gil-refs only.
pub fn get_type_ptr(&self) -> *mut PyTypeObject
gil-refs only.Returns the Python type pointer for this object.
sourcepub fn downcast<T>(&self) -> Result<&T, PyDowncastError<'_>>where
T: PyTypeCheck<AsRefTarget = T>,
Available on crate feature gil-refs only.
pub fn downcast<T>(&self) -> Result<&T, PyDowncastError<'_>>where
T: PyTypeCheck<AsRefTarget = T>,
gil-refs only.Downcast this PyAny to a concrete Python type or pyclass.
Note that you can often avoid downcasting yourself by just specifying the desired type in function or method signatures. However, manual downcasting is sometimes necessary.
For extracting a Rust-only type, see PyAny::extract.
§Example: Downcasting to a specific Python object
use pyo3::prelude::*;
use pyo3::types::{PyDict, PyList};
Python::with_gil(|py| {
let dict = PyDict::new_bound(py);
assert!(dict.is_instance_of::<PyAny>());
let any = dict.as_any();
assert!(any.downcast::<PyDict>().is_ok());
assert!(any.downcast::<PyList>().is_err());
});§Example: Getting a reference to a pyclass
This is useful if you want to mutate a PyObject that
might actually be a pyclass.
use pyo3::prelude::*;
#[pyclass]
struct Class {
i: i32,
}
Python::with_gil(|py| {
let class = Py::new(py, Class { i: 0 }).unwrap().into_bound(py).into_any();
let class_bound: &Bound<'_, Class> = class.downcast()?;
class_bound.borrow_mut().i += 1;
// Alternatively you can get a `PyRefMut` directly
let class_ref: PyRefMut<'_, Class> = class.extract()?;
assert_eq!(class_ref.i, 1);
Ok(())
})sourcepub fn downcast_exact<T>(&self) -> Result<&T, PyDowncastError<'_>>where
T: PyTypeInfo<AsRefTarget = T>,
Available on crate feature gil-refs only.
pub fn downcast_exact<T>(&self) -> Result<&T, PyDowncastError<'_>>where
T: PyTypeInfo<AsRefTarget = T>,
gil-refs only.Downcast this PyAny to a concrete Python type or pyclass (but not a subclass of it).
It is almost always better to use PyAny::downcast because it accounts for Python
subtyping. Use this method only when you do not want to allow subtypes.
The advantage of this method over PyAny::downcast is that it is faster. The implementation
of downcast_exact uses the equivalent of the Python expression type(self) is T, whereas
downcast uses isinstance(self, T).
For extracting a Rust-only type, see PyAny::extract.
§Example: Downcasting to a specific Python object but not a subtype
use pyo3::prelude::*;
use pyo3::types::{PyBool, PyLong};
Python::with_gil(|py| {
let b = PyBool::new_bound(py, true);
assert!(b.is_instance_of::<PyBool>());
let any: &Bound<'_, PyAny> = b.as_any();
// `bool` is a subtype of `int`, so `downcast` will accept a `bool` as an `int`
// but `downcast_exact` will not.
assert!(any.downcast::<PyLong>().is_ok());
assert!(any.downcast_exact::<PyLong>().is_err());
assert!(any.downcast_exact::<PyBool>().is_ok());
});sourcepub unsafe fn downcast_unchecked<T>(&self) -> &Twhere
T: HasPyGilRef<AsRefTarget = T>,
Available on crate feature gil-refs only.
pub unsafe fn downcast_unchecked<T>(&self) -> &Twhere
T: HasPyGilRef<AsRefTarget = T>,
gil-refs only.Converts this PyAny to a concrete Python type without checking validity.
§Safety
Callers must ensure that the type is valid or risk type confusion.
sourcepub fn extract<'py, D>(&'py self) -> PyResult<D>where
D: FromPyObjectBound<'py, 'py>,
Available on crate feature gil-refs only.
pub fn extract<'py, D>(&'py self) -> PyResult<D>where
D: FromPyObjectBound<'py, 'py>,
gil-refs only.Extracts some type from the Python object.
This is a wrapper function around
FromPyObject::extract().
sourcepub fn get_refcnt(&self) -> isize
Available on crate feature gil-refs only.
pub fn get_refcnt(&self) -> isize
gil-refs only.Returns the reference count for the Python object.
sourcepub fn repr(&self) -> PyResult<&PyString>
Available on crate feature gil-refs only.
pub fn repr(&self) -> PyResult<&PyString>
gil-refs only.Computes the “repr” representation of self.
This is equivalent to the Python expression repr(self).
sourcepub fn str(&self) -> PyResult<&PyString>
Available on crate feature gil-refs only.
pub fn str(&self) -> PyResult<&PyString>
gil-refs only.Computes the “str” representation of self.
This is equivalent to the Python expression str(self).
sourcepub fn hash(&self) -> PyResult<isize>
Available on crate feature gil-refs only.
pub fn hash(&self) -> PyResult<isize>
gil-refs only.Retrieves the hash code of self.
This is equivalent to the Python expression hash(self).
sourcepub fn len(&self) -> PyResult<usize>
Available on crate feature gil-refs only.
pub fn len(&self) -> PyResult<usize>
gil-refs only.Returns the length of the sequence or mapping.
This is equivalent to the Python expression len(self).
sourcepub fn dir(&self) -> PyResult<&PyList>
Available on crate feature gil-refs only.
pub fn dir(&self) -> PyResult<&PyList>
gil-refs only.Returns the list of attributes of this object.
This is equivalent to the Python expression dir(self).
sourcepub fn is_instance(&self, ty: &PyAny) -> PyResult<bool>
Available on crate feature gil-refs only.
pub fn is_instance(&self, ty: &PyAny) -> PyResult<bool>
gil-refs only.Checks whether this object is an instance of type ty.
This is equivalent to the Python expression isinstance(self, ty).
sourcepub fn is_exact_instance(&self, ty: &PyAny) -> bool
Available on crate feature gil-refs only.
pub fn is_exact_instance(&self, ty: &PyAny) -> bool
gil-refs only.Checks whether this object is an instance of exactly type ty (not a subclass).
This is equivalent to the Python expression type(self) is ty.
sourcepub fn is_instance_of<T: PyTypeInfo>(&self) -> bool
Available on crate feature gil-refs only.
pub fn is_instance_of<T: PyTypeInfo>(&self) -> bool
gil-refs only.Checks whether this object is an instance of type T.
This is equivalent to the Python expression isinstance(self, T),
if the type T is known at compile time.
sourcepub fn is_exact_instance_of<T: PyTypeInfo>(&self) -> bool
Available on crate feature gil-refs only.
pub fn is_exact_instance_of<T: PyTypeInfo>(&self) -> bool
gil-refs only.Checks whether this object is an instance of exactly type T.
This is equivalent to the Python expression type(self) is T,
if the type T is known at compile time.
sourcepub fn contains<V>(&self, value: V) -> PyResult<bool>where
V: ToPyObject,
Available on crate feature gil-refs only.
pub fn contains<V>(&self, value: V) -> PyResult<bool>where
V: ToPyObject,
gil-refs only.Determines if self contains value.
This is equivalent to the Python expression value in self.
sourcepub fn py(&self) -> Python<'_>
Available on crate feature gil-refs only.
pub fn py(&self) -> Python<'_>
gil-refs only.Returns a GIL marker constrained to the lifetime of this type.
sourcepub fn as_ptr(&self) -> *mut PyObject
Available on crate feature gil-refs only.
pub fn as_ptr(&self) -> *mut PyObject
gil-refs only.Returns the raw FFI pointer represented by self.
§Safety
Callers are responsible for ensuring that the pointer does not outlive self.
The reference is borrowed; callers should not decrease the reference count when they are finished with the pointer.
sourcepub fn into_ptr(&self) -> *mut PyObject
Available on crate feature gil-refs only.
pub fn into_ptr(&self) -> *mut PyObject
gil-refs only.Returns an owned raw FFI pointer represented by self.
§Safety
The reference is owned; when finished the caller should either transfer ownership
of the pointer or decrease the reference count (e.g. with pyo3::ffi::Py_DecRef).
Trait Implementations§
source§impl AsPyPointer for PyCapsule
impl AsPyPointer for PyCapsule
source§impl<'py> FromPyObject<'py> for &'py PyCapsule
Available on crate feature gil-refs only.
impl<'py> FromPyObject<'py> for &'py PyCapsule
gil-refs only.source§impl PyNativeType for PyCapsule
Available on crate feature gil-refs only.
impl PyNativeType for PyCapsule
gil-refs only.source§type AsRefSource = PyCapsule
type AsRefSource = PyCapsule
Py<T> smart pointer.source§fn as_borrowed(&self) -> Borrowed<'_, '_, Self::AsRefSource>
fn as_borrowed(&self) -> Borrowed<'_, '_, Self::AsRefSource>
source§unsafe fn unchecked_downcast(obj: &PyAny) -> &Self
unsafe fn unchecked_downcast(obj: &PyAny) -> &Self
source§impl PyTypeInfo for PyCapsule
impl PyTypeInfo for PyCapsule
source§const MODULE: Option<&'static str> = _
const MODULE: Option<&'static str> = _
gil-refs only.source§fn type_object_raw(py: Python<'_>) -> *mut PyTypeObject
fn type_object_raw(py: Python<'_>) -> *mut PyTypeObject
gil-refs only.source§fn is_type_of_bound(obj: &Bound<'_, PyAny>) -> bool
fn is_type_of_bound(obj: &Bound<'_, PyAny>) -> bool
gil-refs only.object is an instance of this type or a subclass of this type.source§fn type_object(py: Python<'_>) -> &PyType
fn type_object(py: Python<'_>) -> &PyType
PyTypeInfo::type_object will be replaced by PyTypeInfo::type_object_bound in a future PyO3 versiongil-refs only.source§fn type_object_bound(py: Python<'_>) -> Bound<'_, PyType>
fn type_object_bound(py: Python<'_>) -> Bound<'_, PyType>
gil-refs only.source§fn is_type_of(object: &PyAny) -> bool
fn is_type_of(object: &PyAny) -> bool
PyTypeInfo::is_type_of will be replaced by PyTypeInfo::is_type_of_bound in a future PyO3 versiongil-refs only.object is an instance of this type or a subclass of this type.source§fn is_exact_type_of(object: &PyAny) -> bool
fn is_exact_type_of(object: &PyAny) -> bool
PyTypeInfo::is_exact_type_of will be replaced by PyTypeInfo::is_exact_type_of_bound in a future PyO3 versiongil-refs only.object is an instance of this type.source§impl ToPyObject for PyCapsule
Available on crate feature gil-refs only.
impl ToPyObject for PyCapsule
gil-refs only.impl DerefToPyAny for PyCapsule
Auto Trait Implementations§
impl !Freeze for PyCapsule
impl !RefUnwindSafe for PyCapsule
impl !Send for PyCapsule
impl !Sync for PyCapsule
impl Unpin for PyCapsule
impl UnwindSafe for PyCapsule
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<'p, T> FromPyPointer<'p> for Twhere
T: 'p + PyNativeType,
impl<'p, T> FromPyPointer<'p> for Twhere
T: 'p + PyNativeType,
source§unsafe fn from_owned_ptr_or_opt(
py: Python<'p>,
ptr: *mut PyObject,
) -> Option<&'p T>
unsafe fn from_owned_ptr_or_opt( py: Python<'p>, ptr: *mut PyObject, ) -> Option<&'p T>
Py::from_owned_ptr_or_opt(py, ptr) or Bound::from_owned_ptr_or_opt(py, ptr) insteadgil-refs only.PyObject. Read moresource§unsafe fn from_borrowed_ptr_or_opt(
_py: Python<'p>,
ptr: *mut PyObject,
) -> Option<&'p T>
unsafe fn from_borrowed_ptr_or_opt( _py: Python<'p>, ptr: *mut PyObject, ) -> Option<&'p T>
Py::from_borrowed_ptr_or_opt(py, ptr) or Bound::from_borrowed_ptr_or_opt(py, ptr) insteadgil-refs only.PyObject. Read moresource§unsafe fn from_owned_ptr_or_panic(
py: Python<'p>,
ptr: *mut PyObject,
) -> &'p Self
unsafe fn from_owned_ptr_or_panic( py: Python<'p>, ptr: *mut PyObject, ) -> &'p Self
Py::from_owned_ptr(py, ptr) or Bound::from_owned_ptr(py, ptr) insteadgil-refs only.PyObject or panic. Read moresource§unsafe fn from_owned_ptr(py: Python<'p>, ptr: *mut PyObject) -> &'p Self
unsafe fn from_owned_ptr(py: Python<'p>, ptr: *mut PyObject) -> &'p Self
Py::from_owned_ptr(py, ptr) or Bound::from_owned_ptr(py, ptr) insteadgil-refs only.PyObject or panic. Read moresource§unsafe fn from_owned_ptr_or_err(
py: Python<'p>,
ptr: *mut PyObject,
) -> PyResult<&'p Self>
unsafe fn from_owned_ptr_or_err( py: Python<'p>, ptr: *mut PyObject, ) -> PyResult<&'p Self>
Py::from_owned_ptr_or_err(py, ptr) or Bound::from_owned_ptr_or_err(py, ptr) insteadgil-refs only.PyObject. Read moresource§unsafe fn from_borrowed_ptr_or_panic(
py: Python<'p>,
ptr: *mut PyObject,
) -> &'p Self
unsafe fn from_borrowed_ptr_or_panic( py: Python<'p>, ptr: *mut PyObject, ) -> &'p Self
Py::from_borrowed_ptr(py, ptr) or Bound::from_borrowed_ptr(py, ptr) insteadgil-refs only.PyObject. Read moresource§unsafe fn from_borrowed_ptr(py: Python<'p>, ptr: *mut PyObject) -> &'p Self
unsafe fn from_borrowed_ptr(py: Python<'p>, ptr: *mut PyObject) -> &'p Self
Py::from_borrowed_ptr(py, ptr) or Bound::from_borrowed_ptr(py, ptr) insteadgil-refs only.PyObject. Read moresource§unsafe fn from_borrowed_ptr_or_err(
py: Python<'p>,
ptr: *mut PyObject,
) -> PyResult<&'p Self>
unsafe fn from_borrowed_ptr_or_err( py: Python<'p>, ptr: *mut PyObject, ) -> PyResult<&'p Self>
Py::from_borrowed_ptr_or_err(py, ptr) or Bound::from_borrowed_ptr_or_err(py, ptr) insteadgil-refs only.PyObject. Read moresource§impl<T> HasPyGilRef for Twhere
T: PyNativeType,
impl<T> HasPyGilRef for Twhere
T: PyNativeType,
source§type AsRefTarget = T
type AsRefTarget = T
gil-refs only.source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self into a Left variant of Either<Self, Self>
if into_left is true.
Converts self into a Right variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self into a Left variant of Either<Self, Self>
if into_left(&self) returns true.
Converts self into a Right variant of Either<Self, Self>
otherwise. Read moresource§impl<'v, T> PyTryFrom<'v> for Twhere
T: PyTypeInfo<AsRefTarget = T> + PyNativeType,
impl<'v, T> PyTryFrom<'v> for Twhere
T: PyTypeInfo<AsRefTarget = T> + PyNativeType,
source§fn try_from<V>(value: V) -> Result<&'v T, PyDowncastError<'v>>
fn try_from<V>(value: V) -> Result<&'v T, PyDowncastError<'v>>
value.downcast::<T>() instead of T::try_from(value)gil-refs only.source§fn try_from_exact<V>(value: V) -> Result<&'v T, PyDowncastError<'v>>
fn try_from_exact<V>(value: V) -> Result<&'v T, PyDowncastError<'v>>
value.downcast_exact::<T>() instead of T::try_from_exact(value)gil-refs only.source§unsafe fn try_from_unchecked<V>(value: V) -> &'v T
unsafe fn try_from_unchecked<V>(value: V) -> &'v T
value.downcast_unchecked::<T>() instead of T::try_from_unchecked(value)gil-refs only.