forked from
nonbinary.computer/jacquard
A better Rust ATProto crate
trait for deser workarounds, v1
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crates/jacquard-common/src/bos.rs
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crates/jacquard-common/src/bos.rs
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/// for strings of 22 bytes or fewer.
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pub type DefaultStr = SmolStr;
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/// Construct `S` from either a borrowed `&'de str` or an owned `SmolStr`.
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///
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/// Validated string types (Handle, Did, Nsid, etc.) may need to normalise input during
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/// deserialization (e.g. lowercasing handles). The normalisation always produces a `SmolStr`,
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/// but when the input is already valid the deserializer wants to borrow directly from the
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/// input buffer. This trait provides the two construction paths so that a single custom
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/// deserialize visitor can produce any backing type.
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pub trait StrConsumer<'de, 'r>: Bos<str> + Sized {
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/// Construct from a borrowed string slice (zero-copy path).
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fn from_borrowed_str(s: &'de str) -> Self;
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/// Construct from an owned `SmolStr` (normalisation/allocation path).
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fn from_smolstr(s: &'r SmolStr) -> Self;
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}
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impl<'de, 'r> StrConsumer<'de, 'r> for SmolStr {
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#[inline]
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fn from_borrowed_str(s: &'de str) -> Self {
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SmolStr::new(s)
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}
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#[inline]
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fn from_smolstr(s: &'r SmolStr) -> Self {
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s.clone()
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}
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}
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impl<'de, 'r> StrConsumer<'de, 'r> for String {
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#[inline]
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fn from_borrowed_str(s: &'de str) -> Self {
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s.into()
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}
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#[inline]
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fn from_smolstr(s: &'r SmolStr) -> Self {
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s.clone().into()
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}
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}
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impl<'de, 'r> StrConsumer<'de, 'r> for &'de str
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where
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'r: 'de,
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{
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#[inline]
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fn from_borrowed_str(s: &'de str) -> Self {
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s
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}
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#[inline]
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fn from_smolstr(s: &'r SmolStr) -> Self {
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s.as_str()
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}
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}
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impl<'de, 'r> StrConsumer<'de, 'r> for CowStr<'de> {
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#[inline]
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fn from_borrowed_str(s: &'de str) -> Self {
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CowStr::Borrowed(s)
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}
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#[inline]
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fn from_smolstr(s: &'r SmolStr) -> Self {
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CowStr::Owned(s.clone())
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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crates/jacquard-common/src/lib.rs
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-1
crates/jacquard-common/src/lib.rs
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pub use cowstr::CowStr;
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pub use into_static::IntoStatic;
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pub use bos::{Bos, BorrowOrShare, DefaultStr};
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pub use bos::{Bos, BorrowOrShare, DefaultStr, StrConsumer};
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/// A copy-on-write immutable string type that uses [`smol_str::SmolStr`] for
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/// the "owned" variant.