Add a way to clone using gitoxide without removing git2 just yet.

Author: Byron

src/index/diff/mod.rs

@@ -186,7 +186,7 @@ impl Index {
                     .replace_refspecs(Some(spec.as_str()), git::remote::Direction::Fetch)
                     .expect("valid statically known refspec");
             }
-            let res: git::remote::fetch::Outcome<'_> = remote
+            let res: git::remote::fetch::Outcome = remote
                 .connect(git::remote::Direction::Fetch, progress)?
                 .prepare_fetch(Default::default())?
                 .receive(should_interrupt)?;

src/index/init.rs

@@ -1,7 +1,8 @@
-use crate::index::{CloneOptions, LAST_SEEN_REFNAME};
+use crate::index::{CloneOptions, CloneOptions2, LAST_SEEN_REFNAME};
 use crate::Index;
 use git_repository as git;
 use std::path::Path;
+use std::sync::atomic::AtomicBool;
 
 /// The error returned by various initialization methods.
 #[derive(Debug, thiserror::Error)]
@@ -13,6 +14,18 @@ pub enum Error {
     Open(#[from] git::open::Error),
 }
 
+/// The error returned by various initialization methods.
+#[derive(Debug, thiserror::Error)]
+#[allow(missing_docs)]
+pub enum Error2 {
+    #[error(transparent)]
+    PrepareClone(#[from] git::clone::prepare::Error),
+    #[error(transparent)]
+    Fetch(#[from] git::clone::fetch::Error),
+    #[error(transparent)]
+    Open(#[from] git::open::Error),
+}
+
 /// Initialization
 impl Index {
     /// Return a new `Index` instance from the given `path`, which should contain a bare or non-bare
@@ -94,6 +107,68 @@ impl Index {
         })
     }
 
+    /// Return a new `Index` instance from the given `path`, which should contain a bare clone of the `crates.io` index.
+    /// If the directory does not contain the repository or does not exist, it will be cloned from
+    /// the official location automatically (with complete history).
+    ///
+    /// An error will occour if the repository exists and the remote URL does not match the given repository URL.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::sync::atomic::AtomicBool;
+    /// use crates_index_diff::{Index, index, git};
+    ///
+    /// # let path = tempdir::TempDir::new("index").unwrap();
+    /// // Note that credentials are automatically picked up from the standard git configuration.
+    /// let mut options = index::CloneOptions2 {
+    ///   url: "https://github.com/rust-lang/staging.crates.io-index".into(),
+    /// };
+    ///
+    ///
+    /// let index = Index::from_path_or_cloned_with_options2(path, git::progress::Discard, &AtomicBool::default(), options)?;
+    /// # Ok::<(), crates_index_diff::index::init::Error2>(())
+    /// ```
+    pub fn from_path_or_cloned_with_options2(
+        path: impl AsRef<Path>,
+        progress: impl git::Progress,
+        should_interrupt: &AtomicBool,
+        CloneOptions2 { url }: CloneOptions2,
+    ) -> Result<Index, Error2> {
+        let path = path.as_ref();
+        let mut repo = match git::open(path) {
+            Ok(repo) => repo,
+            Err(git::open::Error::NotARepository(_)) => {
+                let (repo, _out) =
+                    git::prepare_clone_bare(url, path)?.fetch_only(progress, should_interrupt)?;
+                repo
+            }
+            Err(err) => return Err(err.into()),
+        }
+        .apply_environment();
+
+        repo.object_cache_size_if_unset(4 * 1024 * 1024);
+        Ok(Index {
+            repo,
+            remote_name: Some("origin"),
+            branch_name: "master",
+            seen_ref_name: LAST_SEEN_REFNAME,
+        })
+    }
+
+    /// Return a new `Index` instance from the given `path`, which should contain a bare or non-bare
+    /// clone of the `crates.io` index.
+    /// If the directory does not contain the repository or does not exist, it will be cloned from
+    /// the official location automatically (with complete history).
+    pub fn from_path_or_cloned2(path: impl AsRef<Path>) -> Result<Index, Error2> {
+        Index::from_path_or_cloned_with_options2(
+            path,
+            git::progress::Discard,
+            &AtomicBool::default(),
+            CloneOptions2::default(),
+        )
+    }
+
     /// Return a new `Index` instance from the given `path`, which should contain a bare or non-bare
     /// clone of the `crates.io` index.
     /// If the directory does not contain the repository or does not exist, it will be cloned from

src/index/mod.rs

@@ -22,6 +22,20 @@ impl<'a> Default for CloneOptions<'a> {
     }
 }
 
+/// Options for cloning the crates-io index.
+pub struct CloneOptions2 {
+    /// The url to clone the crates-index repository from.
+    pub url: String,
+}
+
+impl Default for CloneOptions2 {
+    fn default() -> Self {
+        CloneOptions2 {
+            url: INDEX_GIT_URL.into(),
+        }
+    }
+}
+
 /// Access
 impl Index {
     /// Return the crates.io repository.