feat: add dirs::TBD to make it possible to know where the index sho…

…uld be looked for.

This might be interesting also for tools that deal with the data alone, like `cargo-cache`.

src/dirs.rs

@@ -1,11 +1,11 @@
 use crate::Error;
 
-/// Get the disk location of the specified url, as well as its canonical form,
-/// exactly as cargo would
+/// Get the disk location of the specified `url`, as well as its canonical form,
+/// exactly as cargo would.
 ///
 /// `cargo_home` is used to root the directory at specific location, if not
-/// specified `CARGO_HOME` or else the default cargo location is used as the root
-pub(crate) fn get_index_details(
+/// specified `CARGO_HOME` or else the default cargo location is used as the root.
+pub fn local_path_and_canonical_url(
     url: &str,
     cargo_home: Option<&std::path::Path>,
 ) -> Result<(std::path::PathBuf, String), Error> {

src/git/mod.rs

@@ -1,6 +1,6 @@
 #![allow(clippy::result_large_err)]
 use crate::dedupe::DedupeContext;
-use crate::dirs::{crate_name_to_relative_path, get_index_details};
+use crate::dirs::{crate_name_to_relative_path, local_path_and_canonical_url};
 use crate::error::GixError;
 use crate::{path_max_byte_len, Crate, Error, IndexConfig, GitIndex};
 use gix::config::tree::Key;
@@ -82,7 +82,7 @@ impl GitIndex {
     ///
     /// It can be used to access custom registries.
     pub fn from_url(url: &str) -> Result<Self, Error> {
-        let (path, canonical_url) = get_index_details(url, None)?;
+        let (path, canonical_url) = local_path_and_canonical_url(url, None)?;
         Self::from_path_and_url(path, canonical_url)
     }
 

src/lib.rs

@@ -134,6 +134,7 @@ pub use config::IndexConfig;
 
 mod dedupe;
 mod dirs;
+pub use dirs::local_path_and_canonical_url;
 
 /// Re-exports in case you want to inspect specific error details
 pub mod error;

src/sparse.rs

@@ -1,7 +1,7 @@
 use std::io;
 use std::path::{Path, PathBuf};
 
-use crate::{Crate, dirs::get_index_details, Error, IndexConfig, path_max_byte_len, SparseIndex};
+use crate::{Crate, dirs::local_path_and_canonical_url, Error, IndexConfig, path_max_byte_len, SparseIndex};
 use crate::dirs::crate_name_to_relative_path;
 
 /// The default URL of the crates.io HTTP index, see [`SparseIndex::from_url`] and [`SparseIndex::new_cargo_default`]
@@ -40,7 +40,7 @@ impl SparseIndex {
             return Err(Error::Url(url.to_owned()));
         }
 
-        let (path, url) = get_index_details(url, Some(cargo_home.as_ref()))?;
+        let (path, url) = local_path_and_canonical_url(url, Some(cargo_home.as_ref()))?;
         Ok(Self::at_path(path, url))
     }