Mercurial > hg
diff rust/hg-cpython/src/ref_sharing.rs @ 44204:bafdaf4858d8
rust-cpython: inline PySharedState::try_borrow_mut()
Since the core borrowing/leaking logic has been moved to PySharedRef* and
PyLeaked*, it doesn't make sense that PySharedState had a function named
"try_borrow_mut". Let's turn it into a pure data struct.
author | Yuya Nishihara <yuya@tcha.org> |
---|---|
date | Sat, 19 Oct 2019 16:34:02 +0900 |
parents | 2a24ead003f0 |
children | f015d679f08c |
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--- a/rust/hg-cpython/src/ref_sharing.rs Sat Oct 12 23:34:05 2019 +0900 +++ b/rust/hg-cpython/src/ref_sharing.rs Sat Oct 19 16:34:02 2019 +0900 @@ -57,26 +57,6 @@ } impl PySharedState { - fn try_borrow_mut<'a, T>( - &'a self, - py: Python<'a>, - pyrefmut: RefMut<'a, T>, - ) -> PyResult<RefMut<'a, T>> { - match self.current_borrow_count(py) { - 0 => { - // Note that this wraps around to the same value if mutably - // borrowed more than usize::MAX times, which wouldn't happen - // in practice. - self.generation.fetch_add(1, Ordering::Relaxed); - Ok(pyrefmut) - } - _ => Err(AlreadyBorrowed::new( - py, - "Cannot borrow mutably while immutably borrowed", - )), - } - } - /// Return a reference to the wrapped data and its state with an /// artificial static lifetime. /// We need to be protected by the GIL for thread-safety. @@ -113,6 +93,14 @@ fn current_generation(&self, _py: Python) -> usize { self.generation.load(Ordering::Relaxed) } + + fn increment_generation(&self, py: Python) { + assert_eq!(self.current_borrow_count(py), 0); + // Note that this wraps around to the same value if mutably + // borrowed more than usize::MAX times, which wouldn't happen + // in practice. + self.generation.fetch_add(1, Ordering::Relaxed); + } } /// Helper to keep the borrow count updated while the shared object is @@ -170,11 +158,18 @@ &'a self, py: Python<'a>, ) -> PyResult<RefMut<'a, T>> { + if self.py_shared_state.current_borrow_count(py) > 0 { + return Err(AlreadyBorrowed::new( + py, + "Cannot borrow mutably while immutably borrowed", + )); + } let inner_ref = self .inner .try_borrow_mut() .map_err(|e| AlreadyBorrowed::new(py, e.to_string()))?; - self.py_shared_state.try_borrow_mut(py, inner_ref) + self.py_shared_state.increment_generation(py); + Ok(inner_ref) } }