pyo3/src/lib.rs

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// Copyright (c) 2016 Daniel Grunwald
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//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
#![cfg_attr(feature="nightly", feature(
const_fn, // for GILProtected::new (#24111)
shared, // for std::ptr::Shared (#27730)
specialization, // for impl FromPyObject<'source> for Vec<...> (#31844)
))]
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#![allow(unused_imports)] // because some imports are only necessary with python 2.x or 3.x
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//! Rust bindings to the Python interpreter.
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//!
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//! # Ownership and Lifetimes
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//! In Python, all objects are implicitly reference counted.
//! In rust, we will use the `PyObject` type to represent a reference to a Python object.
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//!
//! The method `clone_ref()` (from trait `PyClone`) can be used to create additional
//! references to the same Python object.
//!
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//! Because all Python objects potentially have multiple owners, the
//! concept of Rust mutability does not apply to Python objects.
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//! As a result, this API will allow mutating Python objects even if they are not stored
//! in a mutable Rust variable.
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//!
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//! The Python interpreter uses a global interpreter lock (GIL)
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//! to ensure thread-safety.
//! This API uses a zero-sized `struct Python<'p>` as a token to indicate
//! that a function can assume that the GIL is held.
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//!
//! You obtain a `Python` instance by acquiring the GIL,
//! and have to pass it into all operations that call into the Python runtime.
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//!
//! # Error Handling
//! The vast majority of operations in this library will return `PyResult<...>`.
//! This is an alias for the type `Result<..., PyErr>`.
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//!
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//! A `PyErr` represents a Python exception. Errors within the PyO3 library are
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//! also exposed as Python exceptions.
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//!
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//! # Example
//! ```
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//! extern crate pyo3;
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//!
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//! use pyo3::{Python, PyDict, PyResult};
//!
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//! fn main() {
//! let gil = Python::acquire_gil();
//! hello(gil.python()).unwrap();
//! }
//!
//! fn hello(py: Python) -> PyResult<()> {
//! let sys = py.import("sys")?;
//! let version: String = sys.get(py, "version")?.extract(py)?;
//!
//! let locals = PyDict::new(py);
//! locals.set_item(py, "os", py.import("os")?)?;
//! let user: String = py.eval("os.getenv('USER') or os.getenv('USERNAME')", None, Some(&locals))?.extract(py)?;
//!
//! println!("Hello {}, I'm Python {}", user, version);
//! Ok(())
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//! }
//! ```
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extern crate libc;
#[macro_use] pub extern crate pyo3cls;
pub use pyo3cls as cls;
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pub mod ffi;
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pub use ffi::Py_ssize_t;
pub use err::{PyErr, PyResult};
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pub use objects::*;
pub use python::{Python, PythonObject, PythonObjectWithCheckedDowncast, PythonObjectDowncastError, PythonObjectWithTypeObject, PyClone, PyDrop};
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pub use pythonrun::{GILGuard, GILProtected, prepare_freethreaded_python};
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pub use conversion::{FromPyObject, RefFromPyObject, ToPyObject, ToPyTuple};
pub use py_class::{CompareOp};
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pub use objectprotocol::{ObjectProtocol};
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#[allow(non_camel_case_types)]
pub type Py_hash_t = ffi::Py_hash_t;
use std::{ptr, mem};
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/// Constructs a `&'static CStr` literal.
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macro_rules! cstr(
($s: tt) => (
// TODO: verify that $s is a string literal without nuls
unsafe {
::std::ffi::CStr::from_ptr(concat!($s, "\0").as_ptr() as *const _)
}
);
);
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// AST coercion macros (https://danielkeep.github.io/tlborm/book/blk-ast-coercion.html)
#[macro_export] #[doc(hidden)]
macro_rules! py_coerce_expr { ($s:expr) => {$s} }
#[macro_export] #[doc(hidden)]
macro_rules! py_coerce_item { ($s:item) => {$s} }
#[macro_export] #[doc(hidden)]
macro_rules! py_replace_expr {
($_t:tt $sub:expr) => {$sub};
}
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#[macro_export] #[doc(hidden)]
macro_rules! py_impl_to_py_object_for_python_object {
($T: ty) => (
/// Identity conversion: allows using existing `PyObject` instances where
/// `T: ToPyObject` is expected.
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impl $crate::ToPyObject for $T where $T: $crate::PythonObject {
#[inline]
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fn to_py_object(&self, py: $crate::Python) -> $crate::PyObject {
$crate::PyClone::clone_ref(self, py).into_object()
}
#[inline]
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fn into_py_object(self, _py: $crate::Python) -> $crate::PyObject {
self.into_object()
}
#[inline]
fn with_borrowed_ptr<F, R>(&self, _py: $crate::Python, f: F) -> R
where F: FnOnce(*mut $crate::_detail::ffi::PyObject) -> R
{
f($crate::PythonObject::as_object(self).as_ptr())
}
}
)
}
#[macro_export] #[doc(hidden)]
macro_rules! py_impl_from_py_object_for_python_object {
($T:ty) => {
impl <'source> $crate::FromPyObject<'source> for $T {
#[inline]
fn extract(py: $crate::Python, obj: &'source $crate::PyObject) -> $crate::PyResult<$T> {
use $crate::PyClone;
Ok(try!(obj.clone_ref(py).cast_into::<$T>(py)))
}
}
impl <'source> $crate::FromPyObject<'source> for &'source $T {
#[inline]
fn extract(py: $crate::Python, obj: &'source $crate::PyObject) -> $crate::PyResult<&'source $T> {
Ok(try!(obj.cast_as::<$T>(py)))
}
}
}
}
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pub mod py_class;
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mod python;
mod err;
mod conversion;
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mod objects;
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mod objectprotocol;
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mod pythonrun;
pub mod argparse;
mod function;
pub mod buffer;
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pub mod class;
pub use class::*;
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// re-export for simplicity
pub use std::os::raw::*;
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/// Private re-exports for macros. Do not use.
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#[doc(hidden)]
pub mod _detail {
pub mod ffi {
pub use ::ffi::*;
}
pub mod libc {
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pub use std::os::raw::{c_char, c_void, c_int};
}
pub use err::{from_owned_ptr_or_panic, result_from_owned_ptr};
pub use function::{handle_callback, py_fn_impl, AbortOnDrop,
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PyObjectCallbackConverter, PythonObjectCallbackConverter};
}
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/// Expands to an `extern "C"` function that allows Python to load
/// the rust code as a Python extension module.
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///
/// Macro syntax: `py_module_initializer!($name, $py2_init, $py3_init, |$py, $m| $body)`
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///
/// 1. `name`: The module name as a Rust identifier.
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/// 2. `py3_init`: "PyInit_" + $name. Necessary because macros can't use concat_idents!().
/// 4. A lambda of type `Fn(Python, &PyModule) -> PyResult<()>`.
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/// This function will be called when the module is imported, and is responsible
/// for adding the module's members.
///
/// # Example
/// ```
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/// #[macro_use] extern crate pyo3;
/// use pyo3::{Python, PyResult, PyObject};
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///
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/// py_module_init!(hello, PyInit_hello, |py, m| {
/// m.add(py, "__doc__", "Module documentation string")?;
/// m.add(py, "run", py_fn!(py, run()))?;
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/// Ok(())
/// });
///
/// fn run(py: Python) -> PyResult<PyObject> {
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/// println!("Rust says: Hello Python!");
/// Ok(py.None())
/// }
/// # fn main() {}
/// ```
///
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/// In your `Cargo.toml`, use the `extension-module` feature for the `pyo3` dependency:
/// ```cargo
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/// [dependencies.pyo3]
/// version = "*"
/// features = ["extension-module"]
/// ```
/// The full example project can be found at:
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/// https://github.com/PyO3/setuptools-rust/tree/master/example/extensions
///
/// Rust will compile the code into a file named `libhello.so`, but we have to
/// rename the file in order to use it with Python:
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///
/// ```bash
/// cp ./target/debug/libhello.so ./hello.so
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/// ```
/// (Note: on Mac OS you will have to rename `libhello.dynlib` to `libhello.so`)
///
/// The extension module can then be imported into Python:
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///
/// ```python
/// >>> import hello
/// >>> hello.run()
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/// Rust says: Hello Python!
/// ```
///
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#[macro_export]
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macro_rules! py_module_init {
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($name: ident, $py3: ident, |$py_id: ident, $m_id: ident| $body: expr) => {
#[no_mangle]
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#[allow(non_snake_case)]
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pub unsafe extern "C" fn $py3() -> *mut $crate::ffi::PyObject {
// Nest init function so that $body isn't in unsafe context
fn init($py_id: $crate::Python, $m_id: &$crate::PyModule) -> $crate::PyResult<()> {
$body
}
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static mut MODULE_DEF: $crate::ffi::PyModuleDef = $crate::_detail::ffi::PyModuleDef_INIT;
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// We can't convert &'static str to *const c_char within a static initializer,
// so we'll do it here in the module initialization:
MODULE_DEF.m_name = concat!(stringify!($name), "\0").as_ptr() as *const _;
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$crate::py_module_init_impl(&mut MODULE_DEF, init)
}
}
}
#[doc(hidden)]
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pub unsafe fn py_module_init_impl(
def: *mut ffi::PyModuleDef,
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init: fn(Python, &PyModule) -> PyResult<()>) -> *mut ffi::PyObject
{
let guard = function::AbortOnDrop("py_module_init");
let py = Python::assume_gil_acquired();
ffi::PyEval_InitThreads();
let module = ffi::PyModule_Create(def);
if module.is_null() {
mem::forget(guard);
return module;
}
let module = match PyObject::from_owned_ptr(py, module).cast_into::<PyModule>(py) {
Ok(m) => m,
Err(e) => {
PyErr::from(e).restore(py);
mem::forget(guard);
return ptr::null_mut();
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}
};
let ret = match init(py, &module) {
Ok(()) => module.into_object().steal_ptr(),
Err(e) => {
e.restore(py);
ptr::null_mut()
}
};
mem::forget(guard);
ret
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}