Add ComboIndexCache::cache_path

CHANGELOG.md

@@ -9,6 +9,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 <!-- next-header -->
 ## [Unreleased] - ReleaseDate
+### Added
+- [PR#52](https://github.com/EmbarkStudios/tame-index/pull/52) added `ComboIndexCache::cache_path` to retrieve the path of a particular crate's index entry.
+
 ## [0.9.6] - 2024-03-12
 ### Changed
 - [PR#51](https://github.com/EmbarkStudios/tame-index/pull/51) updated dependencies.

src/error.rs

@@ -22,7 +22,7 @@ pub enum Error {
     #[error(transparent)]
     Io(#[from] std::io::Error),
     /// An I/O error occurred trying to access a specific path
-    #[error("I/O operation failed for path '{}'", .1)]
+    #[error("I/O operation failed for path '{}': {}", .1, .0)]
     IoPath(#[source] std::io::Error, crate::PathBuf),
     /// A user provided URL was invalid
     #[error(transparent)]

src/index.rs

@@ -115,8 +115,7 @@ pub enum ComboIndexCache {
 }
 
 impl ComboIndexCache {
-    /// Retrieves the index metadata for the specified crate name, optionally
-    /// writing a cache entry for it if there was not already an up to date one
+    /// Retrieves the index metadata for the specified crate name
     #[inline]
     pub fn cached_krate(
         &self,
@@ -131,6 +130,16 @@ impl ComboIndexCache {
         }
     }
 
+    /// Gets the path to the cache entry for the specified crate
+    pub fn cache_path(&self, name: crate::KrateName<'_>) -> crate::PathBuf {
+        match self {
+            Self::Git(index) => index.cache.cache_path(name),
+            Self::Sparse(index) => index.cache().cache_path(name),
+            #[cfg(feature = "local")]
+            Self::Local(lr) => lr.krate_path(name),
+        }
+    }
+
     /// Constructs a [`Self`] for the specified index.
     ///
     /// See [`Self::crates_io`] if you want to create a crates.io index based

src/index/local.rs

@@ -136,7 +136,7 @@ impl LocalRegistry {
         name: KrateName<'_>,
         _lock: &FileLock,
     ) -> Result<Option<IndexKrate>, Error> {
-        let index_path = make_path(&self.path, name);
+        let index_path = self.krate_path(name);
 
         let buf = match std::fs::read(&index_path) {
             Ok(buf) => buf,
@@ -146,6 +146,15 @@ impl LocalRegistry {
 
         Ok(Some(IndexKrate::from_slice(&buf)?))
     }
+
+    /// Gets the path to the index entry for the krate.
+    ///
+    /// Note that unlike .cache entries for git and sparse indices, these are not
+    /// binary files, they are just the JSON line format
+    #[inline]
+    pub fn krate_path(&self, name: KrateName<'_>) -> PathBuf {
+        make_path(&self.path, name)
+    }
 }
 
 /// Allows the building of a local registry from a [`RemoteGitIndex`] or [`RemoteSparseIndex`]