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Remove some unsafe; stabilize zerocopy #833

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7 changes: 1 addition & 6 deletions Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -104,13 +104,8 @@ version = "2"
optional = true
version = "1.1.3"

# Public (unstable): Used in `zerocopy` derive
# Unstable: also need RUSTFLAGS="--cfg uuid_unstable" to work
# This feature may break between releases, or be removed entirely before
# stabilization.
# See: https://github.com/uuid-rs/uuid/issues/588
# Public: Used in trait impls on `Uuid`
[dependencies.zerocopy]
optional = true
version = "0.8"
features = ["derive"]

Expand Down
3 changes: 1 addition & 2 deletions src/builder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -431,8 +431,7 @@ impl Uuid {
/// ```
#[inline]
pub fn from_bytes_ref(bytes: &Bytes) -> &Uuid {
// SAFETY: `Bytes` and `Uuid` have the same ABI
unsafe { &*(bytes as *const Bytes as *const Uuid) }
zerocopy::transmute_ref!(bytes)
}

// NOTE: There is no `from_u128_ref` because in little-endian
Expand Down
145 changes: 102 additions & 43 deletions src/fmt.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,10 +11,12 @@

//! Adapters for alternative string formats.

use core::str::FromStr;
use core::{convert::TryInto as _, str::FromStr};

use zerocopy::{transmute_ref, FromBytes, Immutable, IntoBytes, KnownLayout, Unaligned};

use crate::{
std::{borrow::Borrow, fmt, ptr, str},
std::{borrow::Borrow, fmt, str},
Error, Uuid, Variant,
};

Expand Down Expand Up @@ -67,25 +69,85 @@ impl fmt::UpperHex for Uuid {

/// Format a [`Uuid`] as a hyphenated string, like
/// `67e55044-10b1-426f-9247-bb680e5fe0c8`.
#[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
#[derive(
Clone,
Copy,
Debug,
Default,
Eq,
Hash,
Ord,
PartialEq,
PartialOrd,
IntoBytes,
FromBytes,
KnownLayout,
Immutable,
Unaligned,
)]
#[repr(transparent)]
pub struct Hyphenated(Uuid);

/// Format a [`Uuid`] as a simple string, like
/// `67e5504410b1426f9247bb680e5fe0c8`.
#[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
#[derive(
Clone,
Copy,
Debug,
Default,
Eq,
Hash,
Ord,
PartialEq,
PartialOrd,
IntoBytes,
FromBytes,
KnownLayout,
Immutable,
Unaligned,
)]
#[repr(transparent)]
pub struct Simple(Uuid);

/// Format a [`Uuid`] as a URN string, like
/// `urn:uuid:67e55044-10b1-426f-9247-bb680e5fe0c8`.
#[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
#[derive(
Clone,
Copy,
Debug,
Default,
Eq,
Hash,
Ord,
PartialEq,
PartialOrd,
IntoBytes,
FromBytes,
KnownLayout,
Immutable,
Unaligned,
)]
#[repr(transparent)]
pub struct Urn(Uuid);

/// Format a [`Uuid`] as a braced hyphenated string, like
/// `{67e55044-10b1-426f-9247-bb680e5fe0c8}`.
#[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
#[derive(
Clone,
Copy,
Debug,
Default,
Eq,
Hash,
Ord,
PartialEq,
PartialOrd,
IntoBytes,
FromBytes,
KnownLayout,
Immutable,
Unaligned,
)]
#[repr(transparent)]
pub struct Braced(Uuid);

Expand All @@ -99,8 +161,7 @@ impl Uuid {
/// Get a borrowed [`Hyphenated`] formatter.
#[inline]
pub fn as_hyphenated(&self) -> &Hyphenated {
// SAFETY: `Uuid` and `Hyphenated` have the same ABI
unsafe { &*(self as *const Uuid as *const Hyphenated) }
transmute_ref!(self)
}

/// Get a [`Simple`] formatter.
Expand All @@ -112,8 +173,7 @@ impl Uuid {
/// Get a borrowed [`Simple`] formatter.
#[inline]
pub fn as_simple(&self) -> &Simple {
// SAFETY: `Uuid` and `Simple` have the same ABI
unsafe { &*(self as *const Uuid as *const Simple) }
transmute_ref!(self)
}

/// Get a [`Urn`] formatter.
Expand All @@ -125,8 +185,7 @@ impl Uuid {
/// Get a borrowed [`Urn`] formatter.
#[inline]
pub fn as_urn(&self) -> &Urn {
// SAFETY: `Uuid` and `Urn` have the same ABI
unsafe { &*(self as *const Uuid as *const Urn) }
transmute_ref!(self)
}

/// Get a [`Braced`] formatter.
Expand All @@ -138,8 +197,7 @@ impl Uuid {
/// Get a borrowed [`Braced`] formatter.
#[inline]
pub fn as_braced(&self) -> &Braced {
// SAFETY: `Uuid` and `Braced` have the same ABI
unsafe { &*(self as *const Uuid as *const Braced) }
transmute_ref!(self)
}
}

Expand Down Expand Up @@ -194,58 +252,59 @@ const fn format_hyphenated(src: &[u8; 16], upper: bool) -> [u8; 36] {
#[inline]
fn encode_simple<'b>(src: &[u8; 16], buffer: &'b mut [u8], upper: bool) -> &'b mut str {
let buf = &mut buffer[..Simple::LENGTH];
let dst = buf.as_mut_ptr();
let buf: &mut [u8; Simple::LENGTH] = buf.try_into().unwrap();
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This is a nice cleanup 👍

*buf = format_simple(src, upper);

// SAFETY: `buf` is guaranteed to be at least `LEN` bytes
// SAFETY: The encoded buffer is ASCII encoded
unsafe {
ptr::write(dst.cast(), format_simple(src, upper));
str::from_utf8_unchecked_mut(buf)
}
unsafe { str::from_utf8_unchecked_mut(buf) }
}

#[inline]
fn encode_hyphenated<'b>(src: &[u8; 16], buffer: &'b mut [u8], upper: bool) -> &'b mut str {
let buf = &mut buffer[..Hyphenated::LENGTH];
let dst = buf.as_mut_ptr();
let buf: &mut [u8; Hyphenated::LENGTH] = buf.try_into().unwrap();
*buf = format_hyphenated(src, upper);

// SAFETY: `buf` is guaranteed to be at least `LEN` bytes
// SAFETY: The encoded buffer is ASCII encoded
unsafe {
ptr::write(dst.cast(), format_hyphenated(src, upper));
str::from_utf8_unchecked_mut(buf)
}
unsafe { str::from_utf8_unchecked_mut(buf) }
}

#[inline]
fn encode_braced<'b>(src: &[u8; 16], buffer: &'b mut [u8], upper: bool) -> &'b mut str {
let buf = &mut buffer[..Braced::LENGTH];
buf[0] = b'{';
buf[Braced::LENGTH - 1] = b'}';
let buf = &mut buffer[..Hyphenated::LENGTH + 2];
let buf: &mut [u8; Hyphenated::LENGTH + 2] = buf.try_into().unwrap();

#[derive(IntoBytes)]
#[repr(C)]
struct Braced {
open_curly: u8,
hyphenated: [u8; Hyphenated::LENGTH],
close_curly: u8,
}

// SAFETY: `buf` is guaranteed to be at least `LEN` bytes
// SAFETY: The encoded buffer is ASCII encoded
unsafe {
let dst = buf.as_mut_ptr().add(1);
let braced = Braced {
open_curly: b'{',
hyphenated: format_hyphenated(src, upper),
close_curly: b'}',
};

ptr::write(dst.cast(), format_hyphenated(src, upper));
str::from_utf8_unchecked_mut(buf)
}
*buf = zerocopy::transmute!(braced);

// SAFETY: The encoded buffer is ASCII encoded
unsafe { str::from_utf8_unchecked_mut(buf) }
}

#[inline]
fn encode_urn<'b>(src: &[u8; 16], buffer: &'b mut [u8], upper: bool) -> &'b mut str {
let buf = &mut buffer[..Urn::LENGTH];
buf[..9].copy_from_slice(b"urn:uuid:");

// SAFETY: `buf` is guaranteed to be at least `LEN` bytes
// SAFETY: The encoded buffer is ASCII encoded
unsafe {
let dst = buf.as_mut_ptr().add(9);
let dst = &mut buf[9..(9 + Hyphenated::LENGTH)];
let dst: &mut [u8; Hyphenated::LENGTH] = dst.try_into().unwrap();
*dst = format_hyphenated(src, upper);

ptr::write(dst.cast(), format_hyphenated(src, upper));
str::from_utf8_unchecked_mut(buf)
}
// SAFETY: The encoded buffer is ASCII encoded
unsafe { str::from_utf8_unchecked_mut(buf) }
}

impl Hyphenated {
Expand Down
17 changes: 7 additions & 10 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -438,16 +438,6 @@ pub enum Variant {
#[derive(Clone, Copy, Eq, Ord, PartialEq, PartialOrd)]
#[repr(transparent)]
// NOTE: Also check `NonNilUuid` when ading new derives here
#[cfg_attr(
all(uuid_unstable, feature = "zerocopy"),
derive(
zerocopy::IntoBytes,
zerocopy::FromBytes,
zerocopy::KnownLayout,
zerocopy::Immutable,
zerocopy::Unaligned
)
)]
#[cfg_attr(
feature = "borsh",
derive(borsh_derive::BorshDeserialize, borsh_derive::BorshSerialize)
Expand All @@ -456,6 +446,13 @@ pub enum Variant {
feature = "bytemuck",
derive(bytemuck::Zeroable, bytemuck::Pod, bytemuck::TransparentWrapper)
)]
#[derive(
zerocopy::IntoBytes,
zerocopy::FromBytes,
zerocopy::KnownLayout,
zerocopy::Immutable,
zerocopy::Unaligned,
)]
pub struct Uuid(Bytes);

impl Uuid {
Expand Down