Implement `uv cache dir` (#1734)

## Summary

Like `pip cache dir`, merely prints out the cache directory.

Closes https://github.com/astral-sh/uv/issues/1646.

crates/uv/src/commands/cache_clean.rs

@@ -11,7 +11,7 @@ use crate::commands::ExitStatus;
 use crate::printer::Printer;
 
 /// Clear the cache.
-pub(crate) fn clean(
+pub(crate) fn cache_clean(
     cache: &Cache,
     packages: &[PackageName],
     mut printer: Printer,

crates/uv/src/commands/cache_dir.rs

@@ -0,0 +1,8 @@
+use owo_colors::OwoColorize;
+use uv_cache::Cache;
+use uv_fs::Normalized;
+
+/// Show the cache directory.
+pub(crate) fn cache_dir(cache: &Cache) {
+    anstream::println!("{}", cache.root().normalized_display().cyan());
+}

crates/uv/src/commands/mod.rs

@@ -1,18 +1,20 @@
 use std::process::ExitCode;
 use std::time::Duration;
 
-pub(crate) use clean::clean;
+pub(crate) use cache_clean::cache_clean;
+pub(crate) use cache_dir::cache_dir;
 use distribution_types::InstalledMetadata;
-pub(crate) use freeze::freeze;
 pub(crate) use pip_compile::{extra_name_with_clap_error, pip_compile, Upgrade};
+pub(crate) use pip_freeze::pip_freeze;
 pub(crate) use pip_install::pip_install;
 pub(crate) use pip_sync::pip_sync;
 pub(crate) use pip_uninstall::pip_uninstall;
 pub(crate) use venv::venv;
 
-mod clean;
-mod freeze;
+mod cache_clean;
+mod cache_dir;
 mod pip_compile;
+mod pip_freeze;
 mod pip_install;
 mod pip_sync;
 mod pip_uninstall;

crates/uv/src/commands/pip_freeze.rs

@@ -17,7 +17,7 @@ use crate::commands::ExitStatus;
 use crate::printer::Printer;
 
 /// Enumerate the installed packages in the current environment.
-pub(crate) fn freeze(cache: &Cache, strict: bool, mut printer: Printer) -> Result<ExitStatus> {
+pub(crate) fn pip_freeze(cache: &Cache, strict: bool, mut printer: Printer) -> Result<ExitStatus> {
     // Detect the current Python interpreter.
     let platform = Platform::current()?;
     let venv = Virtualenv::from_env(platform, cache)?;

crates/uv/src/main.rs

@@ -117,7 +117,7 @@ enum Commands {
     Venv(VenvArgs),
     /// Manage the cache.
     Cache(CacheNamespace),
-    /// Clear the cache.
+    /// Remove all items from the cache.
     #[clap(hide = true)]
     Clean(CleanArgs),
     /// Generate shell completion
@@ -133,8 +133,24 @@ struct CacheNamespace {
 
 #[derive(Subcommand)]
 enum CacheCommand {
-    /// Clear the cache.
+    /// Remove all items from the cache.
     Clean(CleanArgs),
+    /// Show the cache directory.
+    Dir,
+}
+
+#[derive(Args)]
+#[allow(clippy::struct_excessive_bools)]
+struct CleanArgs {
+    /// The packages to remove from the cache.
+    package: Vec<PackageName>,
+}
+
+#[derive(Args)]
+#[allow(clippy::struct_excessive_bools)]
+struct DirArgs {
+    /// The packages to remove from the cache.
+    package: Vec<PackageName>,
 }
 
 #[derive(Args)]
@@ -640,13 +656,6 @@ struct PipFreezeArgs {
     strict: bool,
 }
 
-#[derive(Args)]
-#[allow(clippy::struct_excessive_bools)]
-struct CleanArgs {
-    /// The packages to remove from the cache.
-    package: Vec<PackageName>,
-}
-
 #[derive(Args)]
 #[allow(clippy::struct_excessive_bools)]
 struct VenvArgs {
@@ -1033,11 +1042,17 @@ async fn run() -> Result<ExitStatus> {
         }
         Commands::Pip(PipNamespace {
             command: PipCommand::Freeze(args),
-        }) => commands::freeze(&cache, args.strict, printer),
+        }) => commands::pip_freeze(&cache, args.strict, printer),
         Commands::Cache(CacheNamespace {
             command: CacheCommand::Clean(args),
         })
-        | Commands::Clean(args) => commands::clean(&cache, &args.package, printer),
+        | Commands::Clean(args) => commands::cache_clean(&cache, &args.package, printer),
+        Commands::Cache(CacheNamespace {
+            command: CacheCommand::Dir,
+        }) => {
+            commands::cache_dir(&cache);
+            Ok(ExitStatus::Success)
+        }
         Commands::Venv(args) => {
             args.compat_args.validate()?;