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| author | Amanieu d'Antras <amanieu@gmail.com> | 2025-05-18 13:01:35 +0200 |
|---|---|---|
| committer | Amanieu d'Antras <amanieu@gmail.com> | 2025-07-01 18:25:30 +0200 |
| commit | 15bd619d5f12b4d01bb645340e7eea97d7b0e7c7 (patch) | |
| tree | 60e48b4aa5b331bbdca7a32c899c1e5b97129648 /library/alloc/src/vec | |
| parent | f19142044f270760ce0ebc03b2c3a44217d8703d (diff) | |
| download | rust-15bd619d5f12b4d01bb645340e7eea97d7b0e7c7.tar.gz rust-15bd619d5f12b4d01bb645340e7eea97d7b0e7c7.zip | |
Change `{Box,Arc,Rc,Weak}::into_raw` to only work with `A = Global`
Also applies to `Vec::into_raw_parts`. The expectation is that you can round-trip these methods with `from_raw`, but this is only true when using the global allocator. With custom allocators you should instead be using `into_raw_with_allocator` and `from_raw_in`. The implementation of `Box::leak` is changed to use `Box::into_raw_with_allocator` and explicitly leak the allocator (which was already the existing behavior). This is because, for `leak` to be safe, the allocator must not free its underlying backing store. The `Allocator` trait only guarantees that allocated memory remains valid until the allocator is dropped.
Diffstat (limited to 'library/alloc/src/vec')
| -rw-r--r-- | library/alloc/src/vec/mod.rs | 164 |
1 files changed, 82 insertions, 82 deletions
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs index 5bd82560da7..0e4417a0a6b 100644 --- a/library/alloc/src/vec/mod.rs +++ b/library/alloc/src/vec/mod.rs @@ -761,6 +761,88 @@ impl<T> Vec<T> { pub fn peek_mut(&mut self) -> Option<PeekMut<'_, T>> { PeekMut::new(self) } + + /// Decomposes a `Vec<T>` into its raw components: `(pointer, length, capacity)`. + /// + /// Returns the raw pointer to the underlying data, the length of + /// the vector (in elements), and the allocated capacity of the + /// data (in elements). These are the same arguments in the same + /// order as the arguments to [`from_raw_parts`]. + /// + /// After calling this function, the caller is responsible for the + /// memory previously managed by the `Vec`. The only way to do + /// this is to convert the raw pointer, length, and capacity back + /// into a `Vec` with the [`from_raw_parts`] function, allowing + /// the destructor to perform the cleanup. + /// + /// [`from_raw_parts`]: Vec::from_raw_parts + /// + /// # Examples + /// + /// ``` + /// #![feature(vec_into_raw_parts)] + /// let v: Vec<i32> = vec![-1, 0, 1]; + /// + /// let (ptr, len, cap) = v.into_raw_parts(); + /// + /// let rebuilt = unsafe { + /// // We can now make changes to the components, such as + /// // transmuting the raw pointer to a compatible type. + /// let ptr = ptr as *mut u32; + /// + /// Vec::from_raw_parts(ptr, len, cap) + /// }; + /// assert_eq!(rebuilt, [4294967295, 0, 1]); + /// ``` + #[must_use = "losing the pointer will leak memory"] + #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")] + pub fn into_raw_parts(self) -> (*mut T, usize, usize) { + let mut me = ManuallyDrop::new(self); + (me.as_mut_ptr(), me.len(), me.capacity()) + } + + #[doc(alias = "into_non_null_parts")] + /// Decomposes a `Vec<T>` into its raw components: `(NonNull pointer, length, capacity)`. + /// + /// Returns the `NonNull` pointer to the underlying data, the length of + /// the vector (in elements), and the allocated capacity of the + /// data (in elements). These are the same arguments in the same + /// order as the arguments to [`from_parts`]. + /// + /// After calling this function, the caller is responsible for the + /// memory previously managed by the `Vec`. The only way to do + /// this is to convert the `NonNull` pointer, length, and capacity back + /// into a `Vec` with the [`from_parts`] function, allowing + /// the destructor to perform the cleanup. + /// + /// [`from_parts`]: Vec::from_parts + /// + /// # Examples + /// + /// ``` + /// #![feature(vec_into_raw_parts, box_vec_non_null)] + /// + /// let v: Vec<i32> = vec![-1, 0, 1]; + /// + /// let (ptr, len, cap) = v.into_parts(); + /// + /// let rebuilt = unsafe { + /// // We can now make changes to the components, such as + /// // transmuting the raw pointer to a compatible type. + /// let ptr = ptr.cast::<u32>(); + /// + /// Vec::from_parts(ptr, len, cap) + /// }; + /// assert_eq!(rebuilt, [4294967295, 0, 1]); + /// ``` + #[must_use = "losing the pointer will leak memory"] + #[unstable(feature = "box_vec_non_null", reason = "new API", issue = "130364")] + // #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")] + pub fn into_parts(self) -> (NonNull<T>, usize, usize) { + let (ptr, len, capacity) = self.into_raw_parts(); + // SAFETY: A `Vec` always has a non-null pointer. + (unsafe { NonNull::new_unchecked(ptr) }, len, capacity) + } } impl<T, A: Allocator> Vec<T, A> { @@ -1095,88 +1177,6 @@ impl<T, A: Allocator> Vec<T, A> { unsafe { Vec { buf: RawVec::from_nonnull_in(ptr, capacity, alloc), len: length } } } - /// Decomposes a `Vec<T>` into its raw components: `(pointer, length, capacity)`. - /// - /// Returns the raw pointer to the underlying data, the length of - /// the vector (in elements), and the allocated capacity of the - /// data (in elements). These are the same arguments in the same - /// order as the arguments to [`from_raw_parts`]. - /// - /// After calling this function, the caller is responsible for the - /// memory previously managed by the `Vec`. The only way to do - /// this is to convert the raw pointer, length, and capacity back - /// into a `Vec` with the [`from_raw_parts`] function, allowing - /// the destructor to perform the cleanup. - /// - /// [`from_raw_parts`]: Vec::from_raw_parts - /// - /// # Examples - /// - /// ``` - /// #![feature(vec_into_raw_parts)] - /// let v: Vec<i32> = vec![-1, 0, 1]; - /// - /// let (ptr, len, cap) = v.into_raw_parts(); - /// - /// let rebuilt = unsafe { - /// // We can now make changes to the components, such as - /// // transmuting the raw pointer to a compatible type. - /// let ptr = ptr as *mut u32; - /// - /// Vec::from_raw_parts(ptr, len, cap) - /// }; - /// assert_eq!(rebuilt, [4294967295, 0, 1]); - /// ``` - #[must_use = "losing the pointer will leak memory"] - #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")] - pub fn into_raw_parts(self) -> (*mut T, usize, usize) { - let mut me = ManuallyDrop::new(self); - (me.as_mut_ptr(), me.len(), me.capacity()) - } - - #[doc(alias = "into_non_null_parts")] - /// Decomposes a `Vec<T>` into its raw components: `(NonNull pointer, length, capacity)`. - /// - /// Returns the `NonNull` pointer to the underlying data, the length of - /// the vector (in elements), and the allocated capacity of the - /// data (in elements). These are the same arguments in the same - /// order as the arguments to [`from_parts`]. - /// - /// After calling this function, the caller is responsible for the - /// memory previously managed by the `Vec`. The only way to do - /// this is to convert the `NonNull` pointer, length, and capacity back - /// into a `Vec` with the [`from_parts`] function, allowing - /// the destructor to perform the cleanup. - /// - /// [`from_parts`]: Vec::from_parts - /// - /// # Examples - /// - /// ``` - /// #![feature(vec_into_raw_parts, box_vec_non_null)] - /// - /// let v: Vec<i32> = vec![-1, 0, 1]; - /// - /// let (ptr, len, cap) = v.into_parts(); - /// - /// let rebuilt = unsafe { - /// // We can now make changes to the components, such as - /// // transmuting the raw pointer to a compatible type. - /// let ptr = ptr.cast::<u32>(); - /// - /// Vec::from_parts(ptr, len, cap) - /// }; - /// assert_eq!(rebuilt, [4294967295, 0, 1]); - /// ``` - #[must_use = "losing the pointer will leak memory"] - #[unstable(feature = "box_vec_non_null", reason = "new API", issue = "130364")] - // #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")] - pub fn into_parts(self) -> (NonNull<T>, usize, usize) { - let (ptr, len, capacity) = self.into_raw_parts(); - // SAFETY: A `Vec` always has a non-null pointer. - (unsafe { NonNull::new_unchecked(ptr) }, len, capacity) - } - /// Decomposes a `Vec<T>` into its raw components: `(pointer, length, capacity, allocator)`. /// /// Returns the raw pointer to the underlying data, the length of the vector (in elements), |
