How do I build a version tree for a Git repository using LibGit2(Sharp)

Question

Some background:

I'm looking at the possibility of using Git as a data storage layer. Basically I need to keep all versions of some XML files which describe application state. The users needs a "Time Machine" to be able to revert to previous states, as well as branch off previous states etc. This will be hidden behind a service layer, but I am looking at using Git at the back end.

I need to present the evolution of the application's state over time, so I want to build a network diagram showing the changes, the branches etc.

To do this I need to build a version tree visually. Basically, I want to do this:

git log --oneline --graph --decorate --all

I'm using LibGit2Sharp. I've poked around the API, but I'm not seeing anything immediately helpful. I'm also pretty knew to Git, which isn't helping.

this is more a data visualization question, look at .NET libraries for graph visualization (git history is a direct acyclic graph) — CharlesB, Mar 05 '13 at 10:24

score 4 · Answer 1 · edited Sep 14 '19 at 09:26

Using LibGit2Sharp, you can simulate the git log command just by enumerating the Commits. You can also filter the list of commits, or specify some sorting options (like having the list sorted in topological order). More information can be found on the LibGit2Sharp wiki page related to git log.

Using a graph library like QuickGraph (but there are others, as can be found on this other SO question), you can just build the graph like this:

var graph = new AdjacencyGraph<Commit, Edge<Commit>>();

using (var repo = new Repository(path_to_your_repo))
{
    foreach (var c in repo.Commits.Take(20))
    {
        graph.AddVerticesAndEdgeRange(c.Parents.Select(p => new Edge<Commit>(c, p)));
    }
}

You can then output this graph to several visualization formats (graphML, Glee, graphviz). To output it in the graphviz (.dot) format:

var graphviz = new GraphvizAlgorithm<Commit,Edge<Commit>>(graph);
graphviz.FormatVertex +=
    (o, e) =>
        {
            e.VertexFormatter.Label = string.Format("{0} {1}", e.Vertex.Id.ToString(7),
                                                    e.Vertex.MessageShort.Replace("\"", "\\\""));
        };

graphviz.Generate(new FileDotEngine(), @"d:\graph");

Please. Can you give me more specific information? I can get Commit List (repo.Commits), but I cannot import Graph information for each Commit. I desperately need a hint. — jamesnet214, Feb 22 '21 at 14:32

score 1 · Answer 2 · answered Mar 05 '13 at 13:31

libgit2 is about the underlying Git concepts. If you want to show a graph, you need to look at the commits and how they relate to each other. Then you can draw the graph with whatever graphics library you prefer.

If what you want is the output of that command, then running that command is the simplest way.

How do I build a version tree for a Git repository using LibGit2(Sharp)

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