pyo3/types/
set.rs

1use crate::types::PyIterator;
2use crate::{
3    err::{self, PyErr, PyResult},
4    ffi_ptr_ext::FfiPtrExt,
5    instance::Bound,
6    py_result_ext::PyResultExt,
7};
8use crate::{ffi, Borrowed, BoundObject, IntoPyObject, IntoPyObjectExt, PyAny, Python};
9use std::ptr;
10
11/// Represents a Python `set`.
12///
13/// Values of this type are accessed via PyO3's smart pointers, e.g. as
14/// [`Py<PySet>`][crate::Py] or [`Bound<'py, PySet>`][Bound].
15///
16/// For APIs available on `set` objects, see the [`PySetMethods`] trait which is implemented for
17/// [`Bound<'py, PySet>`][Bound].
18#[repr(transparent)]
19pub struct PySet(PyAny);
20
21#[cfg(not(any(PyPy, GraalPy)))]
22pyobject_subclassable_native_type!(PySet, crate::ffi::PySetObject);
23
24#[cfg(not(any(PyPy, GraalPy)))]
25pyobject_native_type!(
26    PySet,
27    ffi::PySetObject,
28    pyobject_native_static_type_object!(ffi::PySet_Type),
29    "builtins",
30    "set",
31    #checkfunction=ffi::PySet_Check
32);
33
34#[cfg(any(PyPy, GraalPy))]
35pyobject_native_type_core!(
36    PySet,
37    pyobject_native_static_type_object!(ffi::PySet_Type),
38    "builtins",
39    "set",
40    #checkfunction=ffi::PySet_Check
41);
42
43impl PySet {
44    /// Creates a new set with elements from the given slice.
45    ///
46    /// Returns an error if some element is not hashable.
47    #[inline]
48    pub fn new<'py, T>(
49        py: Python<'py>,
50        elements: impl IntoIterator<Item = T>,
51    ) -> PyResult<Bound<'py, PySet>>
52    where
53        T: IntoPyObject<'py>,
54    {
55        try_new_from_iter(py, elements)
56    }
57
58    /// Creates a new empty set.
59    pub fn empty(py: Python<'_>) -> PyResult<Bound<'_, PySet>> {
60        unsafe {
61            ffi::PySet_New(ptr::null_mut())
62                .assume_owned_or_err(py)
63                .cast_into_unchecked()
64        }
65    }
66}
67
68/// Implementation of functionality for [`PySet`].
69///
70/// These methods are defined for the `Bound<'py, PySet>` smart pointer, so to use method call
71/// syntax these methods are separated into a trait, because stable Rust does not yet support
72/// `arbitrary_self_types`.
73#[doc(alias = "PySet")]
74pub trait PySetMethods<'py>: crate::sealed::Sealed {
75    /// Removes all elements from the set.
76    fn clear(&self);
77
78    /// Returns the number of items in the set.
79    ///
80    /// This is equivalent to the Python expression `len(self)`.
81    fn len(&self) -> usize;
82
83    /// Checks if set is empty.
84    fn is_empty(&self) -> bool {
85        self.len() == 0
86    }
87
88    /// Determines if the set contains the specified key.
89    ///
90    /// This is equivalent to the Python expression `key in self`.
91    fn contains<K>(&self, key: K) -> PyResult<bool>
92    where
93        K: IntoPyObject<'py>;
94
95    /// Removes the element from the set if it is present.
96    ///
97    /// Returns `true` if the element was present in the set.
98    fn discard<K>(&self, key: K) -> PyResult<bool>
99    where
100        K: IntoPyObject<'py>;
101
102    /// Adds an element to the set.
103    fn add<K>(&self, key: K) -> PyResult<()>
104    where
105        K: IntoPyObject<'py>;
106
107    /// Removes and returns an arbitrary element from the set.
108    fn pop(&self) -> Option<Bound<'py, PyAny>>;
109
110    /// Returns an iterator of values in this set.
111    ///
112    /// # Panics
113    ///
114    /// If PyO3 detects that the set is mutated during iteration, it will panic.
115    fn iter(&self) -> BoundSetIterator<'py>;
116}
117
118impl<'py> PySetMethods<'py> for Bound<'py, PySet> {
119    #[inline]
120    fn clear(&self) {
121        unsafe {
122            ffi::PySet_Clear(self.as_ptr());
123        }
124    }
125
126    #[inline]
127    fn len(&self) -> usize {
128        unsafe { ffi::PySet_Size(self.as_ptr()) as usize }
129    }
130
131    fn contains<K>(&self, key: K) -> PyResult<bool>
132    where
133        K: IntoPyObject<'py>,
134    {
135        fn inner(set: &Bound<'_, PySet>, key: Borrowed<'_, '_, PyAny>) -> PyResult<bool> {
136            match unsafe { ffi::PySet_Contains(set.as_ptr(), key.as_ptr()) } {
137                1 => Ok(true),
138                0 => Ok(false),
139                _ => Err(PyErr::fetch(set.py())),
140            }
141        }
142
143        let py = self.py();
144        inner(
145            self,
146            key.into_pyobject_or_pyerr(py)?.into_any().as_borrowed(),
147        )
148    }
149
150    fn discard<K>(&self, key: K) -> PyResult<bool>
151    where
152        K: IntoPyObject<'py>,
153    {
154        fn inner(set: &Bound<'_, PySet>, key: Borrowed<'_, '_, PyAny>) -> PyResult<bool> {
155            match unsafe { ffi::PySet_Discard(set.as_ptr(), key.as_ptr()) } {
156                1 => Ok(true),
157                0 => Ok(false),
158                _ => Err(PyErr::fetch(set.py())),
159            }
160        }
161
162        let py = self.py();
163        inner(
164            self,
165            key.into_pyobject_or_pyerr(py)?.into_any().as_borrowed(),
166        )
167    }
168
169    fn add<K>(&self, key: K) -> PyResult<()>
170    where
171        K: IntoPyObject<'py>,
172    {
173        fn inner(set: &Bound<'_, PySet>, key: Borrowed<'_, '_, PyAny>) -> PyResult<()> {
174            err::error_on_minusone(set.py(), unsafe {
175                ffi::PySet_Add(set.as_ptr(), key.as_ptr())
176            })
177        }
178
179        let py = self.py();
180        inner(
181            self,
182            key.into_pyobject_or_pyerr(py)?.into_any().as_borrowed(),
183        )
184    }
185
186    fn pop(&self) -> Option<Bound<'py, PyAny>> {
187        let element = unsafe { ffi::PySet_Pop(self.as_ptr()).assume_owned_or_err(self.py()) };
188        element.ok()
189    }
190
191    fn iter(&self) -> BoundSetIterator<'py> {
192        BoundSetIterator::new(self.clone())
193    }
194}
195
196impl<'py> IntoIterator for Bound<'py, PySet> {
197    type Item = Bound<'py, PyAny>;
198    type IntoIter = BoundSetIterator<'py>;
199
200    /// Returns an iterator of values in this set.
201    ///
202    /// # Panics
203    ///
204    /// If PyO3 detects that the set is mutated during iteration, it will panic.
205    fn into_iter(self) -> Self::IntoIter {
206        BoundSetIterator::new(self)
207    }
208}
209
210impl<'py> IntoIterator for &Bound<'py, PySet> {
211    type Item = Bound<'py, PyAny>;
212    type IntoIter = BoundSetIterator<'py>;
213
214    /// Returns an iterator of values in this set.
215    ///
216    /// # Panics
217    ///
218    /// If PyO3 detects that the set is mutated during iteration, it will panic.
219    fn into_iter(self) -> Self::IntoIter {
220        self.iter()
221    }
222}
223
224/// PyO3 implementation of an iterator for a Python `set` object.
225pub struct BoundSetIterator<'py>(Bound<'py, PyIterator>);
226
227impl<'py> BoundSetIterator<'py> {
228    pub(super) fn new(set: Bound<'py, PySet>) -> Self {
229        Self(PyIterator::from_object(&set).expect("set should always be iterable"))
230    }
231}
232
233impl<'py> Iterator for BoundSetIterator<'py> {
234    type Item = Bound<'py, super::PyAny>;
235
236    /// Advances the iterator and returns the next value.
237    fn next(&mut self) -> Option<Self::Item> {
238        self.0
239            .next()
240            .map(|result| result.expect("set iteration should be infallible"))
241    }
242
243    fn size_hint(&self) -> (usize, Option<usize>) {
244        let len = ExactSizeIterator::len(self);
245        (len, Some(len))
246    }
247
248    #[inline]
249    fn count(self) -> usize
250    where
251        Self: Sized,
252    {
253        self.len()
254    }
255}
256
257impl ExactSizeIterator for BoundSetIterator<'_> {
258    fn len(&self) -> usize {
259        self.0.size_hint().0
260    }
261}
262
263#[inline]
264pub(crate) fn try_new_from_iter<'py, T>(
265    py: Python<'py>,
266    elements: impl IntoIterator<Item = T>,
267) -> PyResult<Bound<'py, PySet>>
268where
269    T: IntoPyObject<'py>,
270{
271    let set = unsafe {
272        // We create the `Bound` pointer because its Drop cleans up the set if
273        // user code errors or panics.
274        ffi::PySet_New(std::ptr::null_mut())
275            .assume_owned_or_err(py)?
276            .cast_into_unchecked()
277    };
278    let ptr = set.as_ptr();
279
280    elements.into_iter().try_for_each(|element| {
281        let obj = element.into_pyobject_or_pyerr(py)?;
282        err::error_on_minusone(py, unsafe { ffi::PySet_Add(ptr, obj.as_ptr()) })
283    })?;
284
285    Ok(set)
286}
287
288#[cfg(test)]
289mod tests {
290    use super::PySet;
291    use crate::{
292        conversion::IntoPyObject,
293        types::{PyAnyMethods, PySetMethods},
294        Python,
295    };
296    use std::collections::HashSet;
297
298    #[test]
299    fn test_set_new() {
300        Python::attach(|py| {
301            let set = PySet::new(py, [1]).unwrap();
302            assert_eq!(1, set.len());
303
304            let v = vec![1];
305            assert!(PySet::new(py, &[v]).is_err());
306        });
307    }
308
309    #[test]
310    fn test_set_empty() {
311        Python::attach(|py| {
312            let set = PySet::empty(py).unwrap();
313            assert_eq!(0, set.len());
314            assert!(set.is_empty());
315        });
316    }
317
318    #[test]
319    fn test_set_len() {
320        Python::attach(|py| {
321            let mut v = HashSet::<i32>::new();
322            let ob = (&v).into_pyobject(py).unwrap();
323            let set = ob.cast::<PySet>().unwrap();
324            assert_eq!(0, set.len());
325            v.insert(7);
326            let ob = v.into_pyobject(py).unwrap();
327            let set2 = ob.cast::<PySet>().unwrap();
328            assert_eq!(1, set2.len());
329        });
330    }
331
332    #[test]
333    fn test_set_clear() {
334        Python::attach(|py| {
335            let set = PySet::new(py, [1]).unwrap();
336            assert_eq!(1, set.len());
337            set.clear();
338            assert_eq!(0, set.len());
339        });
340    }
341
342    #[test]
343    fn test_set_contains() {
344        Python::attach(|py| {
345            let set = PySet::new(py, [1]).unwrap();
346            assert!(set.contains(1).unwrap());
347        });
348    }
349
350    #[test]
351    fn test_set_discard() {
352        Python::attach(|py| {
353            let set = PySet::new(py, [1]).unwrap();
354            assert!(!set.discard(2).unwrap());
355            assert_eq!(1, set.len());
356
357            assert!(set.discard(1).unwrap());
358            assert_eq!(0, set.len());
359            assert!(!set.discard(1).unwrap());
360
361            assert!(set.discard(vec![1, 2]).is_err());
362        });
363    }
364
365    #[test]
366    fn test_set_add() {
367        Python::attach(|py| {
368            let set = PySet::new(py, [1, 2]).unwrap();
369            set.add(1).unwrap(); // Add a duplicated element
370            assert!(set.contains(1).unwrap());
371        });
372    }
373
374    #[test]
375    fn test_set_pop() {
376        Python::attach(|py| {
377            let set = PySet::new(py, [1]).unwrap();
378            let val = set.pop();
379            assert!(val.is_some());
380            let val2 = set.pop();
381            assert!(val2.is_none());
382            assert!(py
383                .eval(c"print('Exception state should not be set.')", None, None)
384                .is_ok());
385        });
386    }
387
388    #[test]
389    fn test_set_iter() {
390        Python::attach(|py| {
391            let set = PySet::new(py, [1]).unwrap();
392
393            for el in set {
394                assert_eq!(1i32, el.extract::<'_, i32>().unwrap());
395            }
396        });
397    }
398
399    #[test]
400    fn test_set_iter_bound() {
401        use crate::types::any::PyAnyMethods;
402
403        Python::attach(|py| {
404            let set = PySet::new(py, [1]).unwrap();
405
406            for el in &set {
407                assert_eq!(1i32, el.extract::<i32>().unwrap());
408            }
409        });
410    }
411
412    #[test]
413    #[should_panic]
414    fn test_set_iter_mutation() {
415        Python::attach(|py| {
416            let set = PySet::new(py, [1, 2, 3, 4, 5]).unwrap();
417
418            for _ in &set {
419                let _ = set.add(42);
420            }
421        });
422    }
423
424    #[test]
425    #[should_panic]
426    fn test_set_iter_mutation_same_len() {
427        Python::attach(|py| {
428            let set = PySet::new(py, [1, 2, 3, 4, 5]).unwrap();
429
430            for item in &set {
431                let item: i32 = item.extract().unwrap();
432                let _ = set.del_item(item);
433                let _ = set.add(item + 10);
434            }
435        });
436    }
437
438    #[test]
439    fn test_set_iter_size_hint() {
440        Python::attach(|py| {
441            let set = PySet::new(py, [1]).unwrap();
442            let mut iter = set.iter();
443
444            // Exact size
445            assert_eq!(iter.len(), 1);
446            assert_eq!(iter.size_hint(), (1, Some(1)));
447            iter.next();
448            assert_eq!(iter.len(), 0);
449            assert_eq!(iter.size_hint(), (0, Some(0)));
450        });
451    }
452
453    #[test]
454    fn test_iter_count() {
455        Python::attach(|py| {
456            let set = PySet::new(py, vec![1, 2, 3]).unwrap();
457            assert_eq!(set.iter().count(), 3);
458        })
459    }
460}
pyo3/types/set.rs

pyo3/types/
set.rs
