Add a shared `uv-small-str` crate (#10545)

## Summary

I want to use `SmallString` elsewhere.

Cargo.lock

@@ -5235,10 +5235,10 @@ dependencies = [
 name = "uv-normalize"
 version = "0.0.1"
 dependencies = [
- "arcstr",
  "rkyv",
  "schemars",
  "serde",
+ "uv-small-str",
 ]
 
 [[package]]
@@ -5622,6 +5622,16 @@ dependencies = [
  "winreg",
 ]
 
+[[package]]
+name = "uv-small-str"
+version = "0.0.1"
+dependencies = [
+ "arcstr",
+ "rkyv",
+ "schemars",
+ "serde",
+]
+
 [[package]]
 name = "uv-state"
 version = "0.0.1"

Cargo.toml

@@ -59,10 +59,11 @@ uv-resolver = { path = "crates/uv-resolver" }
 uv-scripts = { path = "crates/uv-scripts" }
 uv-settings = { path = "crates/uv-settings" }
 uv-shell = { path = "crates/uv-shell" }
+uv-small-str = { path = "crates/uv-small-str" }
 uv-state = { path = "crates/uv-state" }
 uv-static = { path = "crates/uv-static" }
-uv-trampoline-builder = { path = "crates/uv-trampoline-builder" }
 uv-tool = { path = "crates/uv-tool" }
+uv-trampoline-builder = { path = "crates/uv-trampoline-builder" }
 uv-types = { path = "crates/uv-types" }
 uv-version = { path = "crates/uv-version" }
 uv-virtualenv = { path = "crates/uv-virtualenv" }

crates/uv-normalize/Cargo.toml

@@ -11,7 +11,11 @@ doctest = false
 workspace = true
 
 [dependencies]
-arcstr = { workspace = true }
+uv-small-str = { workspace = true }
+
 rkyv = { workspace = true }
 schemars = { workspace = true, optional = true }
 serde = { workspace = true, features = ["derive"] }
+
+[features]
+schemars = ["dep:schemars", "uv-small-str/schemars"]

crates/uv-normalize/src/extra_name.rs

@@ -4,7 +4,8 @@ use std::str::FromStr;
 
 use serde::{Deserialize, Deserializer, Serialize};
 
-use crate::small_string::SmallString;
+use uv_small_str::SmallString;
+
 use crate::{validate_and_normalize_owned, validate_and_normalize_ref, InvalidNameError};
 
 /// The normalized name of an extra dependency.

crates/uv-normalize/src/group_name.rs

@@ -5,7 +5,8 @@ use std::sync::LazyLock;
 
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
-use crate::small_string::SmallString;
+use uv_small_str::SmallString;
+
 use crate::{validate_and_normalize_owned, validate_and_normalize_ref, InvalidNameError};
 
 /// The normalized name of a dependency group.

crates/uv-normalize/src/lib.rs

@@ -5,13 +5,13 @@ pub use dist_info_name::DistInfoName;
 pub use extra_name::ExtraName;
 pub use group_name::{GroupName, DEV_DEPENDENCIES};
 pub use package_name::PackageName;
-use small_string::SmallString;
+
+use uv_small_str::SmallString;
 
 mod dist_info_name;
 mod extra_name;
 mod group_name;
 mod package_name;
-mod small_string;
 
 /// Validate and normalize an owned package or extra name.
 pub(crate) fn validate_and_normalize_owned(name: String) -> Result<SmallString, InvalidNameError> {

crates/uv-normalize/src/package_name.rs

@@ -4,7 +4,8 @@ use std::str::FromStr;
 
 use serde::{Deserialize, Deserializer, Serialize};
 
-use crate::small_string::SmallString;
+use uv_small_str::SmallString;
+
 use crate::{validate_and_normalize_owned, validate_and_normalize_ref, InvalidNameError};
 
 /// The normalized name of a package.

crates/uv-small-str/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "uv-small-str"
+version = "0.0.1"
+edition = { workspace = true }
+rust-version = { workspace = true }
+homepage = { workspace = true }
+documentation = { workspace = true }
+repository = { workspace = true }
+authors = { workspace = true }
+license = { workspace = true }
+
+[lib]
+doctest = false
+
+[lints]
+workspace = true
+
+[dependencies]
+arcstr = { workspace = true }
+rkyv = { workspace = true }
+schemars = { workspace = true, optional = true }
+serde = { workspace = true }

crates/uv-small-str/src/lib.rs

@@ -1,11 +1,16 @@
 use std::cmp::PartialEq;
 use std::ops::Deref;
 
-/// An optimized small string type for short identifiers, like package names.
-///
-/// Represented as an [`arcstr::ArcStr`] internally.
-#[derive(Default, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub(crate) struct SmallString(arcstr::ArcStr);
+/// An optimized type for immutable identifiers. Represented as an [`arcstr::ArcStr`] internally.
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct SmallString(arcstr::ArcStr);
+
+impl From<arcstr::ArcStr> for SmallString {
+    #[inline]
+    fn from(s: arcstr::ArcStr) -> Self {
+        Self(s)
+    }
+}
 
 impl From<&str> for SmallString {
     #[inline]
@@ -28,6 +33,13 @@ impl AsRef<str> for SmallString {
     }
 }
 
+impl core::borrow::Borrow<str> for SmallString {
+    #[inline]
+    fn borrow(&self) -> &str {
+        self
+    }
+}
+
 impl Deref for SmallString {
     type Target = str;