cpython/objects/
iterator.rs

1// Copyright (c) 2015 Daniel Grunwald
2//
3// Permission is hereby granted, free of charge, to any person obtaining a copy of this
4// software and associated documentation files (the "Software"), to deal in the Software
5// without restriction, including without limitation the rights to use, copy, modify, merge,
6// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
7// to whom the Software is furnished to do so, subject to the following conditions:
8//
9// The above copyright notice and this permission notice shall be included in all copies or
10// substantial portions of the Software.
11//
12// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
13// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
14// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
15// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
16// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
17// DEALINGS IN THE SOFTWARE.
18
19use crate::conversion::ToPyObject;
20use crate::err::{PyErr, PyResult};
21use crate::ffi;
22use crate::objects::PyObject;
23use crate::python::{Python, PythonObject, PythonObjectDowncastError, ToPythonPointer};
24
25/// A python iterator object.
26///
27/// Unlike other python objects, this class includes a `Python<'p>` token
28/// so that PyIterator can implement the rust `Iterator` trait.
29pub struct PyIterator<'p> {
30    py: Python<'p>,
31    iter: PyObject,
32}
33
34impl<'p> PyIterator<'p> {
35    /// Constructs a PyIterator from a Python iterator object.
36    pub fn from_object(
37        py: Python<'p>,
38        obj: PyObject,
39    ) -> Result<PyIterator<'p>, PythonObjectDowncastError<'p>> {
40        if unsafe { ffi::PyIter_Check(obj.as_ptr()) != 0 } {
41            Ok(PyIterator { py, iter: obj })
42        } else {
43            Err(PythonObjectDowncastError::new(
44                py,
45                "PyIterator",
46                obj.get_type(py),
47            ))
48        }
49    }
50
51    /// Gets the Python iterator object.
52    #[inline]
53    pub fn as_object(&self) -> &PyObject {
54        &self.iter
55    }
56
57    /// Gets the Python iterator object.
58    #[inline]
59    pub fn into_object(self) -> PyObject {
60        self.iter
61    }
62}
63
64impl<'p> Iterator for PyIterator<'p> {
65    type Item = PyResult<PyObject>;
66
67    /// Retrieves the next item from an iterator.
68    /// Returns `None` when the iterator is exhausted.
69    /// If an exception occurs, returns `Some(Err(..))`.
70    /// Further next() calls after an exception occurs are likely
71    /// to repeatedly result in the same exception.
72    fn next(&mut self) -> Option<PyResult<PyObject>> {
73        let py = self.py;
74        match unsafe { PyObject::from_owned_ptr_opt(py, ffi::PyIter_Next(self.iter.as_ptr())) } {
75            Some(obj) => Some(Ok(obj)),
76            None => {
77                if PyErr::occurred(py) {
78                    Some(Err(PyErr::fetch(py)))
79                } else {
80                    None
81                }
82            }
83        }
84    }
85}
86
87#[cfg(test)]
88mod tests {
89    use crate::conversion::ToPyObject;
90    use crate::objectprotocol::ObjectProtocol;
91    use crate::python::{Python, PythonObject};
92
93    #[test]
94    fn vec_iter() {
95        let gil_guard = Python::acquire_gil();
96        let py = gil_guard.python();
97        let obj = vec![10, 20].to_py_object(py).into_object();
98        let mut it = obj.iter(py).unwrap();
99        assert_eq!(10, it.next().unwrap().unwrap().extract(py).unwrap());
100        assert_eq!(20, it.next().unwrap().unwrap().extract(py).unwrap());
101        assert!(it.next().is_none());
102    }
103}
cpython/objects/iterator.rs

cpython/objects/
iterator.rs
