o3/buffer/storage/shared/
str.rs

1use std::{ops, str};
2
3use crate::{
4    buffer,
5    buffer::{storage, storage::regions},
6};
7
8/// An immutable owner whose complete logical range is valid UTF-8.
9#[repr(transparent)]
10pub struct Str<O: buffer::raw::Source = storage::Shared> {
11    text: buffer::raw::Utf8<O>,
12}
13
14impl<O: buffer::raw::Source> Str<O> {
15    pub fn from_utf8(owner: O) -> Result<Self, str::Utf8Error> {
16        Ok(Self {
17            text: buffer::raw::Utf8::try_new(owner)?,
18        })
19    }
20}
21
22impl<O: buffer::raw::Source> ops::Deref for Str<O> {
23    type Target = buffer::raw::Utf8<O>;
24    fn deref(&self) -> &Self::Target {
25        &self.text
26    }
27}
28
29impl TryFrom<&mut String> for Str {
30    type Error = crate::alloc::Exhausted;
31
32    /// Transfers the text on success; allocation failure leaves it unchanged.
33    fn try_from(value: &mut String) -> Result<Self, Self::Error> {
34        let owner = storage::Shared {
35            region: regions::Header::try_new(value)?,
36        };
37        // SAFETY: String transfers its complete validated UTF-8 bytes unchanged.
38        Ok(Self {
39            text: unsafe { buffer::raw::Utf8::new(owner) },
40        })
41    }
42}
43
44const _: () = {
45    assert!(size_of::<Str>() == size_of::<storage::Shared>());
46    assert!(size_of::<Result<Str, crate::alloc::Exhausted>>() == size_of::<Str>());
47};
o3/buffer/storage/shared/str.rs

o3/buffer/storage/shared/
str.rs
