Replacable git backend

[peso]

I'm working on integrating git-graph into gitui. One of the issues I'm trying to deal with is that git-graph is build on git2, whereas gitui is moving from git2 towards gix.

I would like git-graph to continue to work out of the box with git2, but also have the option to compile with a different backend in a way that has no dependency on git2.

[mlange-42]

I guess this could be realized using cargo [features]?

[peso]

Yes, but it requires some refactoring as git2::Oid is used in a lot of places. Maybe something like this for backward compatibility:

type GitGraph = CommitGraph<git2::Oid>;
struct CommitGraph<Oid> {
    commits: Vec<CommitInfo<Oid>>,
    indices: HashMap<Oid, usize>,
    all_branchs: Vec<BranchInfo<Oid>>,
}
struct CommitInfo<Oid>
struct HeadInfo<Oid>
struct BranchInfo<Oid>