Implement conversion from cow to std cow #478
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Did some experiments with |
metrics/src/cow.rs
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| /// Extracts the borrowed data. | ||
| /// | ||
| /// Returns `None` if the data is either shared or owned. | ||
| /// | ||
| /// # Examples | ||
| /// | ||
| /// ``` | ||
| /// use metrics::SharedString; | ||
| /// | ||
| /// let s = SharedString::from_borrowed("foobar"); | ||
| /// assert_eq!(s.as_borrowed(), Some("foobar")); | ||
| /// | ||
| /// let s = SharedString::from_owned("foobar".to_owned()); | ||
| /// assert_eq!(s.as_borrowed(), None); | ||
| /// | ||
| /// let s = SharedString::from_shared("foobar".to_owned().into()); | ||
| /// assert_eq!(s.as_borrowed(), None); | ||
| /// ``` | ||
| pub fn as_borrowed(&self) -> Option<&'a T> { | ||
| match self.metadata.kind() { | ||
| Kind::Owned | Kind::Shared => None, | ||
| Kind::Borrowed => { | ||
| // SAFETY: We know the contained data is borrowed from 'a, we're simply | ||
| // restoring the original immutable reference and returning a copy of it. | ||
| Some(unsafe { &*T::borrowed_from_parts(self.ptr, &self.metadata) }) | ||
| } | ||
| } | ||
| } |
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Unless there's a compelling reason to have this be a standalone method, we should just move the logic down into impl From<Cow<'a, T>> for std::borrow::Cow<'a, T>.
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The problem with that is, the From impl always requires a Clone (or taking ownership, but the way the SharedString is exposed it is usually through a reference), the as_borrowed() allows for a decision. In the future this can be supplemented with as_shared().
That being said, we can reduce the API surface and just impl the From (would be enough for my usecase) and see if more needs come up.
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Removed the |
Dav1dde
changed the title
tobz
added
C-core
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Released in Thanks again for your contribution. 🙏🏻 |
tobz
removed
the
S-awaiting-release
Closes: #474