Struct chromium::UniqueStr

#[repr(C)]
pub struct UniqueStr<'a> { /* fields omitted */ }

A struct for unique str views with a stable layout.

This is a repr(C) variant of &mut str. If you want a variant of &str then you should use UniqueStr instead.

Rationale for using this type is given in the crate level docs.

Unsafety

Because this type is primarily intended to help unsafe Rust we should discuss the precise guarantees offered:

• Validity Invariants
  • The data layout is a *mut u8 and then a usize.
• Soundness Invariants
  • The *mut u8 must point to the start of a valid &mut str.
  • The usize must be the correct length of that valid &mut str.
  • For as long as the UniqueStr exists the memory in question has a unique borrow over it (tracked via PhantomData).
  • The memory must contain value UTF-8 data.

This type matches up with the following C layout:

#include <stdint.h>
// Identical layout to `UniqueStr<'a>`
typedef struct {
  uint8_t *ptr;
  uintptr_t len;
} UniqueStr;

Trait Implementations

impl<'a> Clone for UniqueStr<'a>

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Copy for UniqueStr<'a>

impl<'a> Debug for UniqueStr<'a>

fn fmt(&self, f: &mut Formatter) -> Result

Debug prints as a slice would.

impl<'a> Default for UniqueStr<'a>

fn default() -> Self

Defaults to an empty string.

let unique: UniqueStr<'static> = UniqueStr::default();
assert_eq!(unique.len(), "".len());

impl<'a> Deref for UniqueStr<'a>

type Target = str

The resulting type after dereferencing.

fn deref(&self) -> &str

Dereferences the value.

impl<'a> DerefMut for UniqueStr<'a>

fn deref_mut(&mut self) -> &mut str

Mutably dereferences the value.

impl<'a> From<&'a mut str> for UniqueStr<'a>

fn from(s: &'a mut str) -> Self

Performs the conversion.

impl<'a> From<UniqueStr<'a>> for &'a mut str

fn from(unique: UniqueStr<'a>) -> Self

Performs the conversion.

impl<'a> StableLayout for UniqueStr<'a>