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

// Copyright (c) 2017-present PyO3 Project and Contributors

//! Python Async/Await Interface.
//!
//! Check [the Python C API information](
//! https://docs.python.org/3/c-api/typeobj.html#async-object-structures)
//!
//! [PEP-0492](https://www.python.org/dev/peps/pep-0492/)
//!

use crate::callback::IntoPyCallbackOutput;
use crate::derive_utils::TryFromPyCell;
use crate::err::PyResult;
use crate::{ffi, IntoPy, IntoPyPointer, PyClass, PyObject, Python};

/// Python Async/Await support interface.
///
/// Each method in this trait corresponds to Python async/await implementation.
#[allow(unused_variables)]
pub trait PyAsyncProtocol<'p>: PyClass {
    fn __await__(slf: Self::Receiver) -> Self::Result
    where
        Self: PyAsyncAwaitProtocol<'p>,
    {
        unimplemented!()
    }

    fn __aiter__(slf: Self::Receiver) -> Self::Result
    where
        Self: PyAsyncAiterProtocol<'p>,
    {
        unimplemented!()
    }

    fn __anext__(slf: Self::Receiver) -> Self::Result
    where
        Self: PyAsyncAnextProtocol<'p>,
    {
        unimplemented!()
    }

    fn __aenter__(&'p mut self) -> Self::Result
    where
        Self: PyAsyncAenterProtocol<'p>,
    {
        unimplemented!()
    }

    fn __aexit__(
        &'p mut self,
        exc_type: Option<Self::ExcType>,
        exc_value: Option<Self::ExcValue>,
        traceback: Option<Self::Traceback>,
    ) -> Self::Result
    where
        Self: PyAsyncAexitProtocol<'p>,
    {
        unimplemented!()
    }
}

pub trait PyAsyncAwaitProtocol<'p>: PyAsyncProtocol<'p> {
    type Receiver: TryFromPyCell<'p, Self>;
    type Result: IntoPyCallbackOutput<PyObject>;
}

pub trait PyAsyncAiterProtocol<'p>: PyAsyncProtocol<'p> {
    type Receiver: TryFromPyCell<'p, Self>;
    type Result: IntoPyCallbackOutput<PyObject>;
}

pub trait PyAsyncAnextProtocol<'p>: PyAsyncProtocol<'p> {
    type Receiver: TryFromPyCell<'p, Self>;
    type Result: IntoPyCallbackOutput<PyIterANextOutput>;
}

pub trait PyAsyncAenterProtocol<'p>: PyAsyncProtocol<'p> {
    type Result: IntoPyCallbackOutput<PyObject>;
}

pub trait PyAsyncAexitProtocol<'p>: PyAsyncProtocol<'p> {
    type ExcType: crate::FromPyObject<'p>;
    type ExcValue: crate::FromPyObject<'p>;
    type Traceback: crate::FromPyObject<'p>;
    type Result: IntoPyCallbackOutput<PyObject>;
}

py_unarys_func!(await_, PyAsyncAwaitProtocol, Self::__await__);
py_unarys_func!(aiter, PyAsyncAiterProtocol, Self::__aiter__);
py_unarys_func!(anext, PyAsyncAnextProtocol, Self::__anext__);

/// Output of `__anext__`.
pub enum IterANextOutput<T, U> {
    Yield(T),
    Return(U),
}

pub type PyIterANextOutput = IterANextOutput<PyObject, PyObject>;

impl IntoPyCallbackOutput<*mut ffi::PyObject> for PyIterANextOutput {
    fn convert(self, _py: Python) -> PyResult<*mut ffi::PyObject> {
        match self {
            IterANextOutput::Yield(o) => Ok(o.into_ptr()),
            IterANextOutput::Return(opt) => {
                Err(crate::exceptions::PyStopAsyncIteration::new_err((opt,)))
            }
        }
    }
}

impl<T, U> IntoPyCallbackOutput<PyIterANextOutput> for IterANextOutput<T, U>
where
    T: IntoPy<PyObject>,
    U: IntoPy<PyObject>,
{
    fn convert(self, py: Python) -> PyResult<PyIterANextOutput> {
        match self {
            IterANextOutput::Yield(o) => Ok(IterANextOutput::Yield(o.into_py(py))),
            IterANextOutput::Return(o) => Ok(IterANextOutput::Return(o.into_py(py))),
        }
    }
}

impl<T> IntoPyCallbackOutput<PyIterANextOutput> for Option<T>
where
    T: IntoPy<PyObject>,
{
    fn convert(self, py: Python) -> PyResult<PyIterANextOutput> {
        match self {
            Some(o) => Ok(PyIterANextOutput::Yield(o.into_py(py))),
            None => Ok(PyIterANextOutput::Return(py.None())),
        }
    }
}