showbranch 独立的 LibGit2Sharp 实现

Question

我正在尝试使用 LibGit2Sharp 重新创建 git show-brach --independent 的功能，根据 docs 这样做：Among the <reference>s given, display only the ones that cannot be reached from any other <reference>.

到目前为止，我的最佳尝试如下：

    List<Commit> GetIndependent(IRepository repo, IEnumerable<Commit> commits)
    {
        var indep = new List<Commit>();

        foreach (var commit in commits)
        {
            if (repo.Commits.QueryBy(new CommitFilter
            {
                FirstParentOnly = false,
                IncludeReachableFrom = commit,
                ExcludeReachableFrom = commits.Where(x => x.Equals(commit) == false)
            }).Any())
            {
                indep.Add(commit);
            }
        }

        return indep;
    }

不幸的是，随着历史数量的增加，这变得非常缓慢。实际上，我直接执行 git、解析输出并让 LibGit2Sharp 查找生成的 SHA 比使用上面的代码要快得多。我认为这与 Git 的一些优化有关，但 LibGit2 没有。这甚至在做我想要的吗？如果是这样，在 LibGit2Sharp 中是否有更好的方法来实现这一点？

Answer 1

感谢this question 为我指明了正确的方向，我终于找到了一种利用合并基础的更好方法。

这是新代码：

    /// <summary>
    /// Implementation of `git show-branch --indepenent`
    /// 
    /// "Among the <reference>s given, display only the ones that cannot be reached from any other <reference>"
    /// </summary>
    /// <param name="commitsToCheck"></param>
    /// <returns></returns>
    private List<Commit> GetIndependent(IRepository repo, IEnumerable<Commit> commitsToCheck)
    {
        var commitList = commitsToCheck.ToList();

        for (var i = commitList.Count - 1; i > 0; --i)
        {
            var first = commitList[i];
            for (var j = commitList.Count - 1; j >= 0; --j)
            {
                if (i == j) continue;

                var second = commitList[j];

                var mergeBase = repo.ObjectDatabase.FindMergeBase(first, second);

                if (first.Equals(mergeBase))
                {
                    // First commit (i) is reachable from second (j), so drop i
                    commitList.RemoveAt(i);

                    // No reason to check anything else against this commit
                    j = -1;
                } else if (second.Equals(mergeBase))
                {
                    // Second (j) is reachable from first, so drop j
                    commitList.RemoveAt(j);

                    // If this was at a lower index than i, dec i since we shifted one down
                    if (j < i)
                    {
                        --i;
                    }
                }
            }
        }

        return commitList;
    }