[Updated] D12003: rust: Fix outdated comments in OwningDirstateMap
SimonSapin
phabricator at mercurial-scm.org
Mon Jan 17 13:16:35 UTC 2022
Closed by commit rHG04c04bdd595e: rust: Fix outdated comments in OwningDirstateMap (authored by SimonSapin).
This revision was automatically updated to reflect the committed changes.
REPOSITORY
rHG Mercurial
CHANGES SINCE LAST UPDATE
https://phab.mercurial-scm.org/D12003?vs=31665&id=31678
CHANGES SINCE LAST ACTION
https://phab.mercurial-scm.org/D12003/new/
REVISION DETAIL
https://phab.mercurial-scm.org/D12003
AFFECTED FILES
rust/hg-core/src/dirstate_tree/owning.rs
CHANGE DETAILS
diff --git a/rust/hg-core/src/dirstate_tree/owning.rs b/rust/hg-core/src/dirstate_tree/owning.rs
--- a/rust/hg-core/src/dirstate_tree/owning.rs
+++ b/rust/hg-core/src/dirstate_tree/owning.rs
@@ -21,7 +21,7 @@
/// language cannot represent a lifetime referencing a sibling field.
/// This is not quite a self-referencial struct (moving this struct is not
/// a problem as it doesn’t change the address of the bytes buffer owned
- /// by `PyBytes`) but touches similar borrow-checker limitations.
+ /// by `on_disk`) but touches similar borrow-checker limitations.
ptr: *mut (),
}
@@ -50,13 +50,13 @@
// SAFETY: We cast the type-erased pointer back to the same type it had
// in `new`, except with a different lifetime parameter. This time we
// connect the lifetime to that of `self`. This cast is valid because
- // `self` owns the same `PyBytes` whose buffer `DirstateMap`
- // references. That buffer has a stable memory address because the byte
- // string value of a `PyBytes` is immutable.
+ // `self` owns the same `on_disk` whose buffer `DirstateMap`
+ // references. That buffer has a stable memory address because our
+ // `Self::new_empty` counstructor requires `StableDeref`.
let ptr: *mut DirstateMap<'a> = self.ptr.cast();
// SAFETY: we dereference that pointer, connecting the lifetime of the
- // new `&mut` to that of `self`. This is valid because the
- // raw pointer is to a boxed value, and `self` owns that box.
+ // new `&mut` to that of `self`. This is valid because the
+ // raw pointer is to a boxed value, and `self` owns that box.
(&self.on_disk, unsafe { &mut *ptr })
}
@@ -65,7 +65,7 @@
}
pub fn get_map<'a>(&'a self) -> &'a DirstateMap<'a> {
- // SAFETY: same reasoning as in `get_mut` above.
+ // SAFETY: same reasoning as in `get_pair_mut` above.
let ptr: *mut DirstateMap<'a> = self.ptr.cast();
unsafe { &*ptr }
}
@@ -79,13 +79,13 @@
fn drop(&mut self) {
// Silence a "field is never read" warning, and demonstrate that this
// value is still alive.
- let _ = &self.on_disk;
+ let _: &Box<dyn Deref<Target = [u8]> + Send> = &self.on_disk;
// SAFETY: this cast is the same as in `get_mut`, and is valid for the
// same reason. `self.on_disk` still exists at this point, drop glue
// will drop it implicitly after this `drop` method returns.
let ptr: *mut DirstateMap<'_> = self.ptr.cast();
// SAFETY: `Box::from_raw` takes ownership of the box away from `self`.
- // This is fine because drop glue does nothig for `*mut ()` and we’re
+ // This is fine because drop glue does nothing for `*mut ()` and we’re
// in `drop`, so `get` and `get_mut` cannot be called again.
unsafe { drop(Box::from_raw(ptr)) }
}
To: SimonSapin, #hg-reviewers, Alphare
Cc: Alphare, mercurial-patches
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