--- a/rust/hg-cpython/src/dirstate/owning.rs	Mon Sep 06 13:39:54 2021 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,117 +0,0 @@
-use cpython::PyBytes;
-use cpython::Python;
-use hg::dirstate_tree::dirstate_map::DirstateMap;
-use hg::DirstateError;
-use hg::DirstateParents;
-
-/// Keep a `DirstateMap<'on_disk>` next to the `on_disk` buffer that it
-/// borrows. This is similar to the owning-ref crate.
-///
-/// This is similar to [`OwningRef`] which is more limited because it
-/// represents exactly one `&T` reference next to the value it borrows, as
-/// opposed to a struct that may contain an arbitrary number of references in
-/// arbitrarily-nested data structures.
-///
-/// [`OwningRef`]: https://docs.rs/owning_ref/0.4.1/owning_ref/struct.OwningRef.html
-pub(super) struct OwningDirstateMap {
-    /// Owned handle to a bytes buffer with a stable address.
-    ///
-    /// See <https://docs.rs/owning_ref/0.4.1/owning_ref/trait.StableAddress.html>.
-    on_disk: PyBytes,
-
-    /// Pointer for `Box<DirstateMap<'on_disk>>`, typed-erased because the
-    /// 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.
-    ptr: *mut (),
-}
-
-impl OwningDirstateMap {
-    pub fn new_v1(
-        py: Python,
-        on_disk: PyBytes,
-    ) -> Result<(Self, Option<DirstateParents>), DirstateError> {
-        let bytes: &'_ [u8] = on_disk.data(py);
-        let (map, parents) = DirstateMap::new_v1(bytes)?;
-
-        // Like in `bytes` above, this `'_` lifetime parameter borrows from
-        // the bytes buffer owned by `on_disk`.
-        let ptr: *mut DirstateMap<'_> = Box::into_raw(Box::new(map));
-
-        // Erase the pointed type entirely in order to erase the lifetime.
-        let ptr: *mut () = ptr.cast();
-
-        Ok((Self { on_disk, ptr }, parents))
-    }
-
-    pub fn new_v2(
-        py: Python,
-        on_disk: PyBytes,
-        data_size: usize,
-        tree_metadata: PyBytes,
-    ) -> Result<Self, DirstateError> {
-        let bytes: &'_ [u8] = on_disk.data(py);
-        let map =
-            DirstateMap::new_v2(bytes, data_size, tree_metadata.data(py))?;
-
-        // Like in `bytes` above, this `'_` lifetime parameter borrows from
-        // the bytes buffer owned by `on_disk`.
-        let ptr: *mut DirstateMap<'_> = Box::into_raw(Box::new(map));
-
-        // Erase the pointed type entirely in order to erase the lifetime.
-        let ptr: *mut () = ptr.cast();
-
-        Ok(Self { on_disk, ptr })
-    }
-
-    pub fn get_mut<'a>(&'a mut self) -> &'a mut DirstateMap<'a> {
-        // 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.
-        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.
-        unsafe { &mut *ptr }
-    }
-
-    pub fn get<'a>(&'a self) -> &'a DirstateMap<'a> {
-        // SAFETY: same reasoning as in `get_mut` above.
-        let ptr: *mut DirstateMap<'a> = self.ptr.cast();
-        unsafe { &*ptr }
-    }
-}
-
-impl Drop for OwningDirstateMap {
-    fn drop(&mut self) {
-        // Silence a "field is never read" warning, and demonstrate that this
-        // value is still alive.
-        let _ = &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
-        // in `drop`, so `get` and `get_mut` cannot be called again.
-        unsafe { drop(Box::from_raw(ptr)) }
-    }
-}
-
-fn _static_assert_is_send<T: Send>() {}
-
-fn _static_assert_fields_are_send() {
-    _static_assert_is_send::<PyBytes>();
-    _static_assert_is_send::<Box<DirstateMap<'_>>>();
-}
-
-// SAFETY: we don’t get this impl implicitly because `*mut (): !Send` because
-// thread-safety of raw pointers is unknown in the general case. However this
-// particular raw pointer represents a `Box<DirstateMap<'on_disk>>` that we
-// own. Since that `Box` and `PyBytes` are both `Send` as shown in above, it
-// is sound to mark this struct as `Send` too.
-unsafe impl Send for OwningDirstateMap {}