Mercurial > hg
comparison rust/hg-cpython/src/ref_sharing.rs @ 44235:6b7aef44274b
rust-cpython: remove PySharedRefCell and its companion structs
Also updates py_shared_iterator!() documentation accordingly.
author | Yuya Nishihara <yuya@tcha.org> |
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date | Sat, 25 Jan 2020 17:30:24 +0900 |
parents | e960c30d7e50 |
children |
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44234:bad4e7b361d2 | 44235:6b7aef44274b |
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20 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | 20 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
21 // IN THE SOFTWARE. | 21 // IN THE SOFTWARE. |
22 | 22 |
23 //! Macros for use in the `hg-cpython` bridge library. | 23 //! Macros for use in the `hg-cpython` bridge library. |
24 | 24 |
25 use cpython::{exc, PyClone, PyErr, PyObject, PyResult, Python}; | |
26 use std::cell::{BorrowMutError, Ref, RefCell, RefMut}; | |
27 use std::ops::{Deref, DerefMut}; | |
28 use std::result; | |
29 use std::sync::atomic::{AtomicUsize, Ordering}; | |
30 | |
31 /// Manages the shared state between Python and Rust | |
32 /// | |
33 /// `PySharedState` is owned by `PySharedRefCell`, and is shared across its | |
34 /// derived references. The consistency of these references are guaranteed | |
35 /// as follows: | |
36 /// | |
37 /// - The immutability of `py_class!` object fields. Any mutation of | |
38 /// `PySharedRefCell` is allowed only through its `borrow_mut()`. | |
39 /// - The `py: Python<'_>` token, which makes sure that any data access is | |
40 /// synchronized by the GIL. | |
41 /// - The underlying `RefCell`, which prevents `PySharedRefCell` data from | |
42 /// being directly borrowed or leaked while it is mutably borrowed. | |
43 /// - The `borrow_count`, which is the number of references borrowed from | |
44 /// `PyLeaked`. Just like `RefCell`, mutation is prohibited while `PyLeaked` | |
45 /// is borrowed. | |
46 /// - The `generation` counter, which increments on `borrow_mut()`. `PyLeaked` | |
47 /// reference is valid only if the `current_generation()` equals to the | |
48 /// `generation` at the time of `leak_immutable()`. | |
49 #[derive(Debug, Default)] | |
50 struct PySharedState { | |
51 // The counter variable could be Cell<usize> since any operation on | |
52 // PySharedState is synchronized by the GIL, but being "atomic" makes | |
53 // PySharedState inherently Sync. The ordering requirement doesn't | |
54 // matter thanks to the GIL. | |
55 borrow_count: AtomicUsize, | |
56 generation: AtomicUsize, | |
57 } | |
58 | |
59 impl PySharedState { | |
60 fn current_borrow_count(&self, _py: Python) -> usize { | |
61 self.borrow_count.load(Ordering::Relaxed) | |
62 } | |
63 | |
64 fn increase_borrow_count(&self, _py: Python) { | |
65 // Note that this wraps around if there are more than usize::MAX | |
66 // borrowed references, which shouldn't happen due to memory limit. | |
67 self.borrow_count.fetch_add(1, Ordering::Relaxed); | |
68 } | |
69 | |
70 fn decrease_borrow_count(&self, _py: Python) { | |
71 let prev_count = self.borrow_count.fetch_sub(1, Ordering::Relaxed); | |
72 assert!(prev_count > 0); | |
73 } | |
74 | |
75 fn current_generation(&self, _py: Python) -> usize { | |
76 self.generation.load(Ordering::Relaxed) | |
77 } | |
78 | |
79 fn increment_generation(&self, py: Python) { | |
80 assert_eq!(self.current_borrow_count(py), 0); | |
81 // Note that this wraps around to the same value if mutably | |
82 // borrowed more than usize::MAX times, which wouldn't happen | |
83 // in practice. | |
84 self.generation.fetch_add(1, Ordering::Relaxed); | |
85 } | |
86 } | |
87 | |
88 /// Helper to keep the borrow count updated while the shared object is | |
89 /// immutably borrowed without using the `RefCell` interface. | |
90 struct BorrowPyShared<'a> { | |
91 py: Python<'a>, | |
92 py_shared_state: &'a PySharedState, | |
93 } | |
94 | |
95 impl<'a> BorrowPyShared<'a> { | |
96 fn new( | |
97 py: Python<'a>, | |
98 py_shared_state: &'a PySharedState, | |
99 ) -> BorrowPyShared<'a> { | |
100 py_shared_state.increase_borrow_count(py); | |
101 BorrowPyShared { | |
102 py, | |
103 py_shared_state, | |
104 } | |
105 } | |
106 } | |
107 | |
108 impl Drop for BorrowPyShared<'_> { | |
109 fn drop(&mut self) { | |
110 self.py_shared_state.decrease_borrow_count(self.py); | |
111 } | |
112 } | |
113 | |
114 /// `RefCell` wrapper to be safely used in conjunction with `PySharedState`. | |
115 /// | |
116 /// This object can be stored in a `py_class!` object as a data field. Any | |
117 /// operation is allowed through the `PySharedRef` interface. | |
118 #[derive(Debug)] | |
119 pub struct PySharedRefCell<T> { | |
120 inner: RefCell<T>, | |
121 py_shared_state: PySharedState, | |
122 } | |
123 | |
124 impl<T> PySharedRefCell<T> { | |
125 pub fn new(value: T) -> PySharedRefCell<T> { | |
126 Self { | |
127 inner: RefCell::new(value), | |
128 py_shared_state: PySharedState::default(), | |
129 } | |
130 } | |
131 | |
132 fn borrow<'a>(&'a self, _py: Python<'a>) -> Ref<'a, T> { | |
133 // py_shared_state isn't involved since | |
134 // - inner.borrow() would fail if self is mutably borrowed, | |
135 // - and inner.try_borrow_mut() would fail while self is borrowed. | |
136 self.inner.borrow() | |
137 } | |
138 | |
139 fn try_borrow_mut<'a>( | |
140 &'a self, | |
141 py: Python<'a>, | |
142 ) -> result::Result<RefMut<'a, T>, BorrowMutError> { | |
143 if self.py_shared_state.current_borrow_count(py) > 0 { | |
144 // propagate borrow-by-leaked state to inner to get BorrowMutError | |
145 let _dummy = self.inner.borrow(); | |
146 self.inner.try_borrow_mut()?; | |
147 unreachable!("BorrowMutError must be returned"); | |
148 } | |
149 let inner_ref = self.inner.try_borrow_mut()?; | |
150 self.py_shared_state.increment_generation(py); | |
151 Ok(inner_ref) | |
152 } | |
153 } | |
154 | |
155 /// Sharable data member of type `T` borrowed from the `PyObject`. | |
156 pub struct PySharedRef<'a, T> { | |
157 py: Python<'a>, | |
158 owner: &'a PyObject, | |
159 data: &'a PySharedRefCell<T>, | |
160 } | |
161 | |
162 impl<'a, T> PySharedRef<'a, T> { | |
163 /// # Safety | |
164 /// | |
165 /// The `data` must be owned by the `owner`. Otherwise, the leak count | |
166 /// would get wrong. | |
167 pub unsafe fn new( | |
168 py: Python<'a>, | |
169 owner: &'a PyObject, | |
170 data: &'a PySharedRefCell<T>, | |
171 ) -> Self { | |
172 Self { py, owner, data } | |
173 } | |
174 | |
175 pub fn borrow(&self) -> Ref<'a, T> { | |
176 self.data.borrow(self.py) | |
177 } | |
178 | |
179 /// Mutably borrows the wrapped value. | |
180 /// | |
181 /// # Panics | |
182 /// | |
183 /// Panics if the value is currently borrowed through `PySharedRef` | |
184 /// or `PyLeaked`. | |
185 pub fn borrow_mut(&self) -> RefMut<'a, T> { | |
186 self.try_borrow_mut().expect("already borrowed") | |
187 } | |
188 | |
189 /// Mutably borrows the wrapped value, returning an error if the value | |
190 /// is currently borrowed. | |
191 pub fn try_borrow_mut( | |
192 &self, | |
193 ) -> result::Result<RefMut<'a, T>, BorrowMutError> { | |
194 self.data.try_borrow_mut(self.py) | |
195 } | |
196 | |
197 /// Returns a leaked reference. | |
198 /// | |
199 /// # Panics | |
200 /// | |
201 /// Panics if this is mutably borrowed. | |
202 pub fn leak_immutable(&self) -> PyLeaked<&'static T> { | |
203 let state = &self.data.py_shared_state; | |
204 // make sure self.data isn't mutably borrowed; otherwise the | |
205 // generation number can't be trusted. | |
206 let data_ref = self.borrow(); | |
207 | |
208 // &'static cast is safe because data_ptr and state_ptr are owned | |
209 // by self.owner, and we do have the GIL for thread safety. | |
210 let data_ptr: *const T = &*data_ref; | |
211 let state_ptr: *const PySharedState = state; | |
212 PyLeaked::<&'static T> { | |
213 inner: self.owner.clone_ref(self.py), | |
214 data: unsafe { &*data_ptr }, | |
215 py_shared_state: unsafe { &*state_ptr }, | |
216 generation: state.current_generation(self.py), | |
217 } | |
218 } | |
219 } | |
220 | |
221 /// Allows a `py_class!` generated struct to share references to one of its | |
222 /// data members with Python. | |
223 /// | |
224 /// # Parameters | |
225 /// | |
226 /// * `$name` is the same identifier used in for `py_class!` macro call. | |
227 /// * `$inner_struct` is the identifier of the underlying Rust struct | |
228 /// * `$data_member` is the identifier of the data member of `$inner_struct` | |
229 /// that will be shared. | |
230 /// * `$shared_accessor` is the function name to be generated, which allows | |
231 /// safe access to the data member. | |
232 /// | |
233 /// # Safety | |
234 /// | |
235 /// `$data_member` must persist while the `$name` object is alive. In other | |
236 /// words, it must be an accessor to a data field of the Python object. | |
237 /// | |
238 /// # Example | |
239 /// | |
240 /// ``` | |
241 /// struct MyStruct { | |
242 /// inner: Vec<u32>; | |
243 /// } | |
244 /// | |
245 /// py_class!(pub class MyType |py| { | |
246 /// data inner: PySharedRefCell<MyStruct>; | |
247 /// }); | |
248 /// | |
249 /// py_shared_ref!(MyType, MyStruct, inner, inner_shared); | |
250 /// ``` | |
251 macro_rules! py_shared_ref { | |
252 ( | |
253 $name: ident, | |
254 $inner_struct: ident, | |
255 $data_member: ident, | |
256 $shared_accessor: ident | |
257 ) => { | |
258 impl $name { | |
259 /// Returns a safe reference to the shared `$data_member`. | |
260 /// | |
261 /// This function guarantees that `PySharedRef` is created with | |
262 /// the valid `self` and `self.$data_member(py)` pair. | |
263 fn $shared_accessor<'a>( | |
264 &'a self, | |
265 py: Python<'a>, | |
266 ) -> $crate::ref_sharing::PySharedRef<'a, $inner_struct> { | |
267 use cpython::PythonObject; | |
268 use $crate::ref_sharing::PySharedRef; | |
269 let owner = self.as_object(); | |
270 let data = self.$data_member(py); | |
271 unsafe { PySharedRef::new(py, owner, data) } | |
272 } | |
273 } | |
274 }; | |
275 } | |
276 | |
277 /// Manage immutable references to `PyObject` leaked into Python iterators. | |
278 /// | |
279 /// This reference will be invalidated once the original value is mutably | |
280 /// borrowed. | |
281 pub struct PyLeaked<T> { | |
282 inner: PyObject, | |
283 data: T, | |
284 py_shared_state: &'static PySharedState, | |
285 /// Generation counter of data `T` captured when PyLeaked is created. | |
286 generation: usize, | |
287 } | |
288 | |
289 // DO NOT implement Deref for PyLeaked<T>! Dereferencing PyLeaked | |
290 // without taking Python GIL wouldn't be safe. Also, the underling reference | |
291 // is invalid if generation != py_shared_state.generation. | |
292 | |
293 impl<T> PyLeaked<T> { | |
294 /// Immutably borrows the wrapped value. | |
295 /// | |
296 /// Borrowing fails if the underlying reference has been invalidated. | |
297 /// | |
298 /// # Safety | |
299 /// | |
300 /// The lifetime of the innermost object is cheated. Do not obtain and | |
301 /// copy it out of the borrow scope. See the example of `try_borrow_mut()` | |
302 /// for details. | |
303 pub unsafe fn try_borrow<'a>( | |
304 &'a self, | |
305 py: Python<'a>, | |
306 ) -> PyResult<PyLeakedRef<'a, T>> { | |
307 self.validate_generation(py)?; | |
308 Ok(PyLeakedRef { | |
309 _borrow: BorrowPyShared::new(py, self.py_shared_state), | |
310 data: &self.data, | |
311 }) | |
312 } | |
313 | |
314 /// Mutably borrows the wrapped value. | |
315 /// | |
316 /// Borrowing fails if the underlying reference has been invalidated. | |
317 /// | |
318 /// Typically `T` is an iterator. If `T` is an immutable reference, | |
319 /// `get_mut()` is useless since the inner value can't be mutated. | |
320 /// | |
321 /// # Safety | |
322 /// | |
323 /// The lifetime of the innermost object is cheated. Do not obtain and | |
324 /// copy it out of the borrow scope. For example, the following code | |
325 /// is unsafe: | |
326 /// | |
327 /// ```compile_fail | |
328 /// let slice; | |
329 /// { | |
330 /// let iter = leaked.try_borrow_mut(py); | |
331 /// // slice can outlive since the iterator is of Iter<'static, T> | |
332 /// // type, but it shouldn't. | |
333 /// slice = iter.as_slice(); | |
334 /// } | |
335 /// println!("{:?}", slice); | |
336 /// ``` | |
337 pub unsafe fn try_borrow_mut<'a>( | |
338 &'a mut self, | |
339 py: Python<'a>, | |
340 ) -> PyResult<PyLeakedRefMut<'a, T>> { | |
341 self.validate_generation(py)?; | |
342 Ok(PyLeakedRefMut { | |
343 _borrow: BorrowPyShared::new(py, self.py_shared_state), | |
344 data: &mut self.data, | |
345 }) | |
346 } | |
347 | |
348 /// Converts the inner value by the given function. | |
349 /// | |
350 /// Typically `T` is a static reference to a container, and `U` is an | |
351 /// iterator of that container. | |
352 /// | |
353 /// # Panics | |
354 /// | |
355 /// Panics if the underlying reference has been invalidated. | |
356 /// | |
357 /// This is typically called immediately after the `PyLeaked` is obtained. | |
358 /// In which case, the reference must be valid and no panic would occur. | |
359 /// | |
360 /// # Safety | |
361 /// | |
362 /// The lifetime of the object passed in to the function `f` is cheated. | |
363 /// It's typically a static reference, but is valid only while the | |
364 /// corresponding `PyLeaked` is alive. Do not copy it out of the | |
365 /// function call. | |
366 pub unsafe fn map<U>( | |
367 self, | |
368 py: Python, | |
369 f: impl FnOnce(T) -> U, | |
370 ) -> PyLeaked<U> { | |
371 // Needs to test the generation value to make sure self.data reference | |
372 // is still intact. | |
373 self.validate_generation(py) | |
374 .expect("map() over invalidated leaked reference"); | |
375 | |
376 // f() could make the self.data outlive. That's why map() is unsafe. | |
377 // In order to make this function safe, maybe we'll need a way to | |
378 // temporarily restrict the lifetime of self.data and translate the | |
379 // returned object back to Something<'static>. | |
380 let new_data = f(self.data); | |
381 PyLeaked { | |
382 inner: self.inner, | |
383 data: new_data, | |
384 py_shared_state: self.py_shared_state, | |
385 generation: self.generation, | |
386 } | |
387 } | |
388 | |
389 fn validate_generation(&self, py: Python) -> PyResult<()> { | |
390 if self.py_shared_state.current_generation(py) == self.generation { | |
391 Ok(()) | |
392 } else { | |
393 Err(PyErr::new::<exc::RuntimeError, _>( | |
394 py, | |
395 "Cannot access to leaked reference after mutation", | |
396 )) | |
397 } | |
398 } | |
399 } | |
400 | |
401 /// Immutably borrowed reference to a leaked value. | |
402 pub struct PyLeakedRef<'a, T> { | |
403 _borrow: BorrowPyShared<'a>, | |
404 data: &'a T, | |
405 } | |
406 | |
407 impl<T> Deref for PyLeakedRef<'_, T> { | |
408 type Target = T; | |
409 | |
410 fn deref(&self) -> &T { | |
411 self.data | |
412 } | |
413 } | |
414 | |
415 /// Mutably borrowed reference to a leaked value. | |
416 pub struct PyLeakedRefMut<'a, T> { | |
417 _borrow: BorrowPyShared<'a>, | |
418 data: &'a mut T, | |
419 } | |
420 | |
421 impl<T> Deref for PyLeakedRefMut<'_, T> { | |
422 type Target = T; | |
423 | |
424 fn deref(&self) -> &T { | |
425 self.data | |
426 } | |
427 } | |
428 | |
429 impl<T> DerefMut for PyLeakedRefMut<'_, T> { | |
430 fn deref_mut(&mut self) -> &mut T { | |
431 self.data | |
432 } | |
433 } | |
434 | |
435 /// Defines a `py_class!` that acts as a Python iterator over a Rust iterator. | 25 /// Defines a `py_class!` that acts as a Python iterator over a Rust iterator. |
436 /// | 26 /// |
437 /// TODO: this is a bit awkward to use, and a better (more complicated) | 27 /// TODO: this is a bit awkward to use, and a better (more complicated) |
438 /// procedural macro would simplify the interface a lot. | 28 /// procedural macro would simplify the interface a lot. |
439 /// | 29 /// |
440 /// # Parameters | 30 /// # Parameters |
441 /// | 31 /// |
442 /// * `$name` is the identifier to give to the resulting Rust struct. | 32 /// * `$name` is the identifier to give to the resulting Rust struct. |
443 /// * `$leaked` corresponds to `$leaked` in the matching `py_shared_ref!` call. | 33 /// * `$leaked` corresponds to `UnsafePyLeaked` in the matching `@shared data` |
34 /// declaration. | |
444 /// * `$iterator_type` is the type of the Rust iterator. | 35 /// * `$iterator_type` is the type of the Rust iterator. |
445 /// * `$success_func` is a function for processing the Rust `(key, value)` | 36 /// * `$success_func` is a function for processing the Rust `(key, value)` |
446 /// tuple on iteration success, turning it into something Python understands. | 37 /// tuple on iteration success, turning it into something Python understands. |
447 /// * `$success_func` is the return type of `$success_func` | 38 /// * `$success_func` is the return type of `$success_func` |
448 /// | 39 /// |
457 /// struct MyStruct { | 48 /// struct MyStruct { |
458 /// inner: HashMap<Vec<u8>, Vec<u8>>; | 49 /// inner: HashMap<Vec<u8>, Vec<u8>>; |
459 /// } | 50 /// } |
460 /// | 51 /// |
461 /// py_class!(pub class MyType |py| { | 52 /// py_class!(pub class MyType |py| { |
462 /// data inner: PySharedRefCell<MyStruct>; | 53 /// @shared data inner: MyStruct; |
463 /// | 54 /// |
464 /// def __iter__(&self) -> PyResult<MyTypeItemsIterator> { | 55 /// def __iter__(&self) -> PyResult<MyTypeItemsIterator> { |
465 /// let leaked_ref = self.inner_shared(py).leak_immutable(); | 56 /// let leaked_ref = self.inner_shared(py).leak_immutable(); |
466 /// MyTypeItemsIterator::from_inner( | 57 /// MyTypeItemsIterator::from_inner( |
467 /// py, | 58 /// py, |
481 /// PyBytes::new(py, entry), | 72 /// PyBytes::new(py, entry), |
482 /// ))) | 73 /// ))) |
483 /// } | 74 /// } |
484 /// } | 75 /// } |
485 /// | 76 /// |
486 /// py_shared_ref!(MyType, MyStruct, inner, MyTypeLeakedRef); | |
487 /// | |
488 /// py_shared_iterator!( | 77 /// py_shared_iterator!( |
489 /// MyTypeItemsIterator, | 78 /// MyTypeItemsIterator, |
490 /// PyLeaked<HashMap<'static, Vec<u8>, Vec<u8>>>, | 79 /// UnsafePyLeaked<HashMap<'static, Vec<u8>, Vec<u8>>>, |
491 /// MyType::translate_key_value, | 80 /// MyType::translate_key_value, |
492 /// Option<(PyBytes, PyBytes)> | 81 /// Option<(PyBytes, PyBytes)> |
493 /// ); | 82 /// ); |
494 /// ``` | 83 /// ``` |
495 macro_rules! py_shared_iterator { | 84 macro_rules! py_shared_iterator { |
528 ) | 117 ) |
529 } | 118 } |
530 } | 119 } |
531 }; | 120 }; |
532 } | 121 } |
533 | |
534 #[cfg(test)] | |
535 #[cfg(any(feature = "python27-bin", feature = "python3-bin"))] | |
536 mod test { | |
537 use super::*; | |
538 use cpython::{GILGuard, Python}; | |
539 | |
540 py_class!(class Owner |py| { | |
541 data string: PySharedRefCell<String>; | |
542 }); | |
543 py_shared_ref!(Owner, String, string, string_shared); | |
544 | |
545 fn prepare_env() -> (GILGuard, Owner) { | |
546 let gil = Python::acquire_gil(); | |
547 let py = gil.python(); | |
548 let owner = | |
549 Owner::create_instance(py, PySharedRefCell::new("new".to_owned())) | |
550 .unwrap(); | |
551 (gil, owner) | |
552 } | |
553 | |
554 #[test] | |
555 fn test_leaked_borrow() { | |
556 let (gil, owner) = prepare_env(); | |
557 let py = gil.python(); | |
558 let leaked = owner.string_shared(py).leak_immutable(); | |
559 let leaked_ref = unsafe { leaked.try_borrow(py) }.unwrap(); | |
560 assert_eq!(*leaked_ref, "new"); | |
561 } | |
562 | |
563 #[test] | |
564 fn test_leaked_borrow_mut() { | |
565 let (gil, owner) = prepare_env(); | |
566 let py = gil.python(); | |
567 let leaked = owner.string_shared(py).leak_immutable(); | |
568 let mut leaked_iter = unsafe { leaked.map(py, |s| s.chars()) }; | |
569 let mut leaked_ref = | |
570 unsafe { leaked_iter.try_borrow_mut(py) }.unwrap(); | |
571 assert_eq!(leaked_ref.next(), Some('n')); | |
572 assert_eq!(leaked_ref.next(), Some('e')); | |
573 assert_eq!(leaked_ref.next(), Some('w')); | |
574 assert_eq!(leaked_ref.next(), None); | |
575 } | |
576 | |
577 #[test] | |
578 fn test_leaked_borrow_after_mut() { | |
579 let (gil, owner) = prepare_env(); | |
580 let py = gil.python(); | |
581 let leaked = owner.string_shared(py).leak_immutable(); | |
582 owner.string_shared(py).borrow_mut().clear(); | |
583 assert!(unsafe { leaked.try_borrow(py) }.is_err()); | |
584 } | |
585 | |
586 #[test] | |
587 fn test_leaked_borrow_mut_after_mut() { | |
588 let (gil, owner) = prepare_env(); | |
589 let py = gil.python(); | |
590 let leaked = owner.string_shared(py).leak_immutable(); | |
591 let mut leaked_iter = unsafe { leaked.map(py, |s| s.chars()) }; | |
592 owner.string_shared(py).borrow_mut().clear(); | |
593 assert!(unsafe { leaked_iter.try_borrow_mut(py) }.is_err()); | |
594 } | |
595 | |
596 #[test] | |
597 #[should_panic(expected = "map() over invalidated leaked reference")] | |
598 fn test_leaked_map_after_mut() { | |
599 let (gil, owner) = prepare_env(); | |
600 let py = gil.python(); | |
601 let leaked = owner.string_shared(py).leak_immutable(); | |
602 owner.string_shared(py).borrow_mut().clear(); | |
603 let _leaked_iter = unsafe { leaked.map(py, |s| s.chars()) }; | |
604 } | |
605 | |
606 #[test] | |
607 fn test_try_borrow_mut_while_leaked_ref() { | |
608 let (gil, owner) = prepare_env(); | |
609 let py = gil.python(); | |
610 assert!(owner.string_shared(py).try_borrow_mut().is_ok()); | |
611 let leaked = owner.string_shared(py).leak_immutable(); | |
612 { | |
613 let _leaked_ref = unsafe { leaked.try_borrow(py) }.unwrap(); | |
614 assert!(owner.string_shared(py).try_borrow_mut().is_err()); | |
615 { | |
616 let _leaked_ref2 = unsafe { leaked.try_borrow(py) }.unwrap(); | |
617 assert!(owner.string_shared(py).try_borrow_mut().is_err()); | |
618 } | |
619 assert!(owner.string_shared(py).try_borrow_mut().is_err()); | |
620 } | |
621 assert!(owner.string_shared(py).try_borrow_mut().is_ok()); | |
622 } | |
623 | |
624 #[test] | |
625 fn test_try_borrow_mut_while_leaked_ref_mut() { | |
626 let (gil, owner) = prepare_env(); | |
627 let py = gil.python(); | |
628 assert!(owner.string_shared(py).try_borrow_mut().is_ok()); | |
629 let leaked = owner.string_shared(py).leak_immutable(); | |
630 let mut leaked_iter = unsafe { leaked.map(py, |s| s.chars()) }; | |
631 { | |
632 let _leaked_ref = | |
633 unsafe { leaked_iter.try_borrow_mut(py) }.unwrap(); | |
634 assert!(owner.string_shared(py).try_borrow_mut().is_err()); | |
635 } | |
636 assert!(owner.string_shared(py).try_borrow_mut().is_ok()); | |
637 } | |
638 | |
639 #[test] | |
640 #[should_panic(expected = "mutably borrowed")] | |
641 fn test_leak_while_borrow_mut() { | |
642 let (gil, owner) = prepare_env(); | |
643 let py = gil.python(); | |
644 let _mut_ref = owner.string_shared(py).borrow_mut(); | |
645 owner.string_shared(py).leak_immutable(); | |
646 } | |
647 | |
648 #[test] | |
649 fn test_try_borrow_mut_while_borrow() { | |
650 let (gil, owner) = prepare_env(); | |
651 let py = gil.python(); | |
652 let _ref = owner.string_shared(py).borrow(); | |
653 assert!(owner.string_shared(py).try_borrow_mut().is_err()); | |
654 } | |
655 | |
656 #[test] | |
657 #[should_panic(expected = "already borrowed")] | |
658 fn test_borrow_mut_while_borrow() { | |
659 let (gil, owner) = prepare_env(); | |
660 let py = gil.python(); | |
661 let _ref = owner.string_shared(py).borrow(); | |
662 owner.string_shared(py).borrow_mut(); | |
663 } | |
664 } |