Add `Vec::as_non_null` · qinheping/verify-rust-std@31d575b (original) (raw)

`@@ -1584,7 +1584,8 @@ impl<T, A: Allocator> Vec<T, A> {

1584

`///

1585

`/// This method guarantees that for the purpose of the aliasing model, this method

1586

`/// does not materialize a reference to the underlying slice, and thus the returned pointer

1587

`` -

/// will remain valid when mixed with other calls to [as_ptr] and [as_mut_ptr].

1587

`` +

/// will remain valid when mixed with other calls to [as_ptr], [as_mut_ptr],

1588

`` +

/// and [as_non_null].

1588

1589

`/// Note that calling other methods that materialize mutable references to the slice,

1589

1590

`/// or mutable references to specific elements you are planning on accessing through this pointer,

1590

1591

`/// as well as writing to those elements, may still invalidate this pointer.

`@@ -1621,6 +1622,7 @@ impl<T, A: Allocator> Vec<T, A> {

1621

1622

`///

1622

1623

`` /// [as_mut_ptr]: Vec::as_mut_ptr

1623

1624

`` /// [as_ptr]: Vec::as_ptr

1625

`` +

/// [as_non_null]: Vec::as_non_null

1624

1626

`#[stable(feature = "vec_as_ptr", since = "1.37.0")]

1625

1627

`#[rustc_never_returns_null_ptr]

1626

1628

`#[inline]

`@@ -1640,7 +1642,8 @@ impl<T, A: Allocator> Vec<T, A> {

1640

1642

`///

1641

1643

`/// This method guarantees that for the purpose of the aliasing model, this method

1642

1644

`/// does not materialize a reference to the underlying slice, and thus the returned pointer

1643

`` -

/// will remain valid when mixed with other calls to [as_ptr] and [as_mut_ptr].

1645

`` +

/// will remain valid when mixed with other calls to [as_ptr], [as_mut_ptr],

1646

`` +

/// and [as_non_null].

1644

1647

`/// Note that calling other methods that materialize references to the slice,

1645

1648

`/// or references to specific elements you are planning on accessing through this pointer,

1646

1649

`/// may still invalidate this pointer.

`@@ -1680,6 +1683,7 @@ impl<T, A: Allocator> Vec<T, A> {

1680

1683

`///

1681

1684

`` /// [as_mut_ptr]: Vec::as_mut_ptr

1682

1685

`` /// [as_ptr]: Vec::as_ptr

1686

`` +

/// [as_non_null]: Vec::as_non_null

1683

1687

`#[stable(feature = "vec_as_ptr", since = "1.37.0")]

1684

1688

`#[rustc_never_returns_null_ptr]

1685

1689

`#[inline]

`@@ -1689,6 +1693,69 @@ impl<T, A: Allocator> Vec<T, A> {

1689

1693

`self.buf.ptr()

1690

1694

1691

1695

1696

`` +

/// Returns a NonNull pointer to the vector's buffer, or a dangling

1697

`` +

/// NonNull pointer valid for zero sized reads if the vector didn't allocate.

1698

///

1699

/// The caller must ensure that the vector outlives the pointer this

1700

/// function returns, or else it will end up dangling.

1701

/// Modifying the vector may cause its buffer to be reallocated,

1702

/// which would also make any pointers to it invalid.

1703

///

1704

/// This method guarantees that for the purpose of the aliasing model, this method

1705

/// does not materialize a reference to the underlying slice, and thus the returned pointer

1706

`` +

/// will remain valid when mixed with other calls to [as_ptr], [as_mut_ptr],

1707

`` +

/// and [as_non_null].

1708

/// Note that calling other methods that materialize references to the slice,

1709

/// or references to specific elements you are planning on accessing through this pointer,

1710

/// may still invalidate this pointer.

1711

/// See the second example below for how this guarantee can be used.

1712

///

1713

/// # Examples

1714

///

1715


/// ```

1716

/// #![feature(box_vec_non_null)]

1717

///

1718

/// // Allocate vector big enough for 4 elements.

1719

/// let size = 4;

1720

/// let mut x: Vec = Vec::with_capacity(size);

1721

/// let x_ptr = x.as_non_null();

1722

///

1723

/// // Initialize elements via raw pointer writes, then set length.

1724

/// unsafe {

1725

/// for i in 0..size {

1726

/// x_ptr.add(i).write(i as i32);

1727

/// }

1728

/// x.set_len(size);

1729

/// }

1730

/// assert_eq!(&*x, &[0, 1, 2, 3]);

1731


/// ```

1732

///

1733

/// Due to the aliasing guarantee, the following code is legal:

1734

///

1735


/// ```rust

1736

/// #![feature(box_vec_non_null)]

1737

///

1738

/// unsafe {

1739

/// let mut v = vec![0];

1740

/// let ptr1 = v.as_non_null();

1741

/// ptr1.write(1);

1742

/// let ptr2 = v.as_non_null();

1743

/// ptr2.write(2);

1744

`` +

/// // Notably, the write to ptr2 did not invalidate ptr1:

1745

/// ptr1.write(3);

1746

/// }

1747


/// ```

1748

///

1749

`` +

/// [as_mut_ptr]: Vec::as_mut_ptr

1750

`` +

/// [as_ptr]: Vec::as_ptr

1751

`` +

/// [as_non_null]: Vec::as_non_null

1752

#[unstable(feature = "box_vec_non_null", reason = "new API", issue = "130364")]

1753

#[inline]

1754

pub fn as_non_null(&mut self) -> NonNull {

1755

`` +

// SAFETY: A Vec always has a non-null pointer.

1756

unsafe { NonNull::new_unchecked(self.as_mut_ptr()) }

1757

}

1758

+

1692

1759

`/// Returns a reference to the underlying allocator.

1693

1760

`#[unstable(feature = "allocator_api", issue = "32838")]

1694

1761

`#[inline]

Add Vec::as_non_null · qinheping/verify-rust-std@31d575b (original) (raw)

Add `Vec::as_non_null` · qinheping/verify-rust-std@31d575b (original) (raw)