rust-pyo3-sharedref: replaced borrow/borrow_mut with RwLock namings
The "borrow" word had way too many uses in this context. Originally,
it came from the rust-cpython version, which is based on `RefCell`.
Before this change, we had untracktable stacks of borrows (first the
`Bound`, then the `PySharedRefCell`).
In any case, the change to `RwLock` is far from being neutral, and
we may need in a future without GIL to also expose blocking methods, to
account for in-Rust possible concurrency. Using `read()` and `write()`
right now matches our PyO3 habits anyway, where all non-Sync objects
have to be wrapped in a RwLock.
--- a/rust/pyo3-sharedref/src/lib.rs Sun Dec 15 14:42:53 2024 +0100
+++ b/rust/pyo3-sharedref/src/lib.rs Sun Dec 15 13:58:31 2024 +0100
@@ -93,7 +93,7 @@
/// fn add(slf: &Bound<'_, Self>, i: i32) -> PyResult<()> {
/// let rust_set = &slf.borrow().rust_set;
/// let shared_ref = unsafe { rust_set.borrow_with_owner(slf) };
-/// let mut set_ref = shared_ref.borrow_mut();
+/// let mut set_ref = shared_ref.write();
/// set_ref.insert(i);
/// Ok(())
/// }
@@ -230,38 +230,38 @@
}
impl<'py, T: ?Sized> PySharedRef<'py, T> {
- /// Immutably borrows the wrapped value.
+ /// Take the lock on the wrapped value for read-only operations.
///
/// # Panics
///
- /// Panics if the value is currently mutably borrowed.
- pub fn borrow(&self) -> RwLockReadGuard<'py, T> {
- self.try_borrow().expect("already mutably borrowed")
+ /// Panics if the lock is currently held for write operations.
+ pub fn read(&self) -> RwLockReadGuard<'py, T> {
+ self.try_read().expect("already mutably borrowed")
}
/// Immutably borrows the wrapped value, returning an error if the value
/// is currently mutably borrowed.
- pub fn try_borrow(&self) -> TryLockResult<RwLockReadGuard<'py, T>> {
+ pub fn try_read(&self) -> TryLockResult<RwLockReadGuard<'py, T>> {
// state isn't involved since
- // - data.try_borrow() would fail if self is mutably borrowed,
- // - and data.try_borrow_mut() would fail while self is borrowed.
+ // - data.try_read() would fail if self is mutably borrowed,
+ // - and data.try_write() would fail while self is borrowed.
self.data.try_read()
}
- /// Mutably borrows the wrapped value.
+ /// Take the lock on the wrapped value for write operations.
///
/// Any existing leaked references will be invalidated.
///
/// # Panics
///
- /// Panics if the value is currently borrowed.
- pub fn borrow_mut(&self) -> RwLockWriteGuard<'py, T> {
- self.try_borrow_mut().expect("already borrowed")
+ /// Panics if the lock is currently held.
+ pub fn write(&self) -> RwLockWriteGuard<'py, T> {
+ self.try_write().expect("already borrowed")
}
/// Mutably borrows the wrapped value, returning an error if the value
/// is currently borrowed.
- pub fn try_borrow_mut(&self) -> TryLockResult<RwLockWriteGuard<'py, T>> {
+ pub fn try_write(&self) -> TryLockResult<RwLockWriteGuard<'py, T>> {
// the value may be immutably borrowed through UnsafePyLeaked
if self.state.current_borrow_count(self.py()) > 0 {
// propagate borrow-by-leaked state to data to get BorrowMutError
@@ -291,10 +291,10 @@
) -> Result<UnsafePyLeaked<&'static T>, TryLeakError> {
// make sure self.data isn't mutably borrowed; otherwise the
// generation number wouldn't be trusted.
- let data_ref = self.try_borrow()?;
+ let data_ref = self.try_read()?;
// keep reference to the owner so the data and state are alive,
- // but the data pointer can be invalidated by borrow_mut().
+ // but the data pointer can be invalidated by write().
// the state wouldn't since it is immutable.
let state_ptr: *const PySharedState = self.state;
let data_ptr: *const T = &*data_ref;
@@ -322,7 +322,7 @@
/// as follows:
///
/// - The immutability of `PycCass` object fields. Any mutation of
-/// [`PySharedRefCell`] is allowed only through its `borrow_mut()`.
+/// [`PySharedRefCell`] is allowed only through its `write()`.
/// - The `py: Python<'_>` token, which makes sure that any data access is
/// synchronized by the GIL.
/// - The underlying `RefCell`, which prevents `PySharedRefCell` value from
@@ -330,9 +330,9 @@
/// - The `borrow_count`, which is the number of references borrowed from
/// `UnsafePyLeaked`. Just like `RefCell`, mutation is prohibited while
/// `UnsafePyLeaked` is borrowed.
-/// - The `generation` counter, which increments on `borrow_mut()`.
-/// `UnsafePyLeaked` reference is valid only if the `current_generation()`
-/// equals to the `generation` at the time of `leak_immutable()`.
+/// - The `generation` counter, which increments on `write()`. `UnsafePyLeaked`
+/// reference is valid only if the `current_generation()` equals to the
+/// `generation` at the time of `leak_immutable()`.
#[derive(Debug)]
struct PySharedState {
// The counter variable could be Cell<usize> since any operation on
--- a/rust/pyo3-sharedref/tests/test_sharedref.rs Sun Dec 15 14:42:53 2024 +0100
+++ b/rust/pyo3-sharedref/tests/test_sharedref.rs Sun Dec 15 13:58:31 2024 +0100
@@ -53,7 +53,7 @@
) -> () {
let cell = &owner.borrow_mut().string;
let shared_ref = unsafe { cell.borrow_with_owner(owner) };
- f(&mut shared_ref.borrow_mut());
+ f(&mut shared_ref.write());
}
#[test]
@@ -119,65 +119,65 @@
///
/// Simply returning the `Result` is not possible, because that is
/// returning a reference to data owned by the function
-fn assert_try_borrow_string_mut_ok(owner: &Bound<'_, Owner>) {
+fn assert_try_write_string_ok(owner: &Bound<'_, Owner>) {
let cell = &owner.borrow().string;
let shared_ref = unsafe { cell.borrow_with_owner(owner) };
- assert!(shared_ref.try_borrow_mut().is_ok());
+ assert!(shared_ref.try_write().is_ok());
}
-fn assert_try_borrow_string_mut_err(owner: &Bound<'_, Owner>) {
+fn assert_try_write_string_err(owner: &Bound<'_, Owner>) {
let cell = &owner.borrow().string;
let shared_ref = unsafe { cell.borrow_with_owner(owner) };
- assert!(shared_ref.try_borrow_mut().is_err());
+ assert!(shared_ref.try_write().is_err());
}
-fn assert_try_borrow_string_err(owner: &Bound<'_, Owner>) {
+fn assert_try_read_string_err(owner: &Bound<'_, Owner>) {
let cell = &owner.borrow().string;
let shared_ref = unsafe { cell.borrow_with_owner(owner) };
- assert!(shared_ref.try_borrow().is_err());
+ assert!(shared_ref.try_read().is_err());
}
#[test]
-fn test_try_borrow_mut_while_leaked_ref() -> PyResult<()> {
+fn test_try_write_while_leaked_ref() -> PyResult<()> {
with_setup(|py, owner| {
- assert_try_borrow_string_mut_ok(owner);
+ assert_try_write_string_ok(owner);
let leaked = leak_string(owner);
{
let _leaked_ref = unsafe { leaked.try_borrow(py) }.unwrap();
- assert_try_borrow_string_mut_err(owner);
+ assert_try_write_string_err(owner);
{
let _leaked_ref2 = unsafe { leaked.try_borrow(py) }.unwrap();
- assert_try_borrow_string_mut_err(owner);
+ assert_try_write_string_err(owner);
}
- assert_try_borrow_string_mut_err(owner);
+ assert_try_write_string_err(owner);
}
- assert_try_borrow_string_mut_ok(owner);
+ assert_try_write_string_ok(owner);
Ok(())
})
}
#[test]
-fn test_try_borrow_mut_while_leaked_ref_mut() -> PyResult<()> {
+fn test_try_write_while_leaked_ref_mut() -> PyResult<()> {
with_setup(|py, owner| {
- assert_try_borrow_string_mut_ok(owner);
+ assert_try_write_string_ok(owner);
let leaked = leak_string(owner);
let mut leaked_iter = unsafe { leaked.map(py, |s| s.chars()) };
{
let _leaked_ref =
unsafe { leaked_iter.try_borrow_mut(py) }.unwrap();
- assert_try_borrow_string_mut_err(owner);
+ assert_try_write_string_err(owner);
}
- assert_try_borrow_string_mut_ok(owner);
+ assert_try_write_string_ok(owner);
Ok(())
})
}
#[test]
-fn test_try_leak_while_borrow_mut() -> PyResult<()> {
+fn test_try_leak_while_write() -> PyResult<()> {
with_setup(|_py, owner| {
let cell = &owner.borrow().string;
let shared_ref = unsafe { cell.borrow_with_owner(owner) };
- let _mut_ref = shared_ref.borrow_mut();
+ let _mut_ref = shared_ref.write();
assert!(try_leak_string(owner).is_err());
Ok(())
@@ -186,11 +186,11 @@
#[test]
#[should_panic(expected = "already mutably borrowed")]
-fn test_leak_while_borrow_mut() {
+fn test_leak_while_write() {
with_setup(|_py, owner| {
let cell = &owner.borrow().string;
let shared_ref = unsafe { cell.borrow_with_owner(owner) };
- let _mut_ref = shared_ref.borrow_mut();
+ let _mut_ref = shared_ref.write();
leak_string(owner);
Ok(())
@@ -199,54 +199,54 @@
}
#[test]
-fn test_try_borrow_mut_while_borrow() -> PyResult<()> {
+fn test_try_write_while_borrow() -> PyResult<()> {
with_setup(|_py, owner| {
let cell = &owner.borrow().string;
let shared_ref = unsafe { cell.borrow_with_owner(owner) };
- let _ref = shared_ref.borrow();
+ let _ref = shared_ref.read();
- assert_try_borrow_string_mut_err(owner);
+ assert_try_write_string_err(owner);
Ok(())
})
}
#[test]
#[should_panic(expected = "already borrowed")]
-fn test_borrow_mut_while_borrow() {
+fn test_write_while_borrow() {
with_setup(|_py, owner| {
let cell = &owner.borrow().string;
let shared_ref = unsafe { cell.borrow_with_owner(owner) };
- let _ref = shared_ref.borrow();
+ let _ref = shared_ref.read();
let shared_ref2 = unsafe { cell.borrow_with_owner(owner) };
- let _mut_ref = shared_ref2.borrow_mut();
+ let _mut_ref = shared_ref2.write();
Ok(())
})
.expect("should already have panicked")
}
#[test]
-fn test_try_borrow_while_borrow_mut() -> PyResult<()> {
+fn test_try_borrow_while_write() -> PyResult<()> {
with_setup(|_py, owner| {
let cell = &owner.borrow().string;
let shared_ref = unsafe { cell.borrow_with_owner(owner) };
- let _mut_ref = shared_ref.borrow_mut();
+ let _mut_ref = shared_ref.write();
- assert_try_borrow_string_err(owner);
+ assert_try_read_string_err(owner);
Ok(())
})
}
#[test]
#[should_panic(expected = "already mutably borrowed")]
-fn test_borrow_while_borrow_mut() {
+fn test_borrow_while_write() {
with_setup(|_py, owner| {
let cell = &owner.borrow().string;
let shared_ref = unsafe { cell.borrow_with_owner(owner) };
- let _mut_ref = shared_ref.borrow_mut();
+ let _mut_ref = shared_ref.write();
let shared_ref2 = unsafe { cell.borrow_with_owner(owner) };
- let _ref = shared_ref2.borrow();
+ let _ref = shared_ref2.read();
Ok(())
})
.expect("should already have panicked")