Committing all the libgit2 progress before throwing it away

I don't think libgit2 is the way forward to make any of this work.
There's so much work involved in parsing the git k-v store, and the
library itself is essentially of zero help for most of the heavy
lifting.

1 files changed, 61 insertions, 0 deletions

diff --git a/src/git/log.rs b/src/git/log.rs
new file mode 100644
index 0000000..dab9e69
--- /dev/null
+++ b/src/git/log.rs
@@ -0,0 +1,61 @@
+//! libgit2 log parsing
+
+use crate::git::{self, tree::FileNode};
+use git2::{Oid, Repository};
+use std::collections::{BTreeMap, BTreeSet};
+
+/// A file-commit referenced graph thing
+///
+/// git is _weird_!  It's essentially just a glorified key-value store
+/// and it shows.  There's no utilities to figure out how thing are
+/// related, and all the actual graph things in git are sugar on top
+/// of this store.
+///
+/// In order to make sense of anything in a repo we need to quite
+/// heavily parse the log.  This type here is the result of this
+/// parsing: you can ask it smart questions like "when did this file
+/// change" and it will tell you (sort of).
+#[derive(Default)]
+pub(crate) struct CommitGraph {
+    order: Vec<String>,
+    file_refs: BTreeMap<String, BTreeSet<String>>,
+    commit_refs: BTreeMap<String, CommitNode>,
+}
+
+pub(crate) struct CommitNode {
+    id: String,
+    author: String,
+    touches: BTreeSet<String>,
+    date: String,
+}
+
+fn build_diff_log(repo: &Repository, log: Vec<(String, Vec<FileNode>)>) -> Vec<CommitNode> {
+    todo!()
+}
+
+/// Walk through all commits from a given ref and build a commit graph
+pub(crate) fn create_commit_log(id: String, repo: &Repository) -> CommitGraph {
+    let mut walker = repo.revwalk().unwrap();
+    walker.push(Oid::from_str(id.as_str()).unwrap()).unwrap();
+    let mut v = walker
+        .into_iter()
+        .map(|oid| {
+            let oid = oid.unwrap();
+            repo.find_commit(oid).unwrap()
+        })
+        .collect::<Vec<_>>();
+    v.reverse();
+
+    let log: Vec<_> = v
+        .into_iter()
+        .map(|commit| {
+            let id = format!("{}", commit.id());
+            let tree_u = git::repo::get_tree(&repo, id.as_str());
+            let tree = git::tree::parse_tree(tree_u, &repo);
+            (id, tree.flatten())
+        })
+        .collect();
+
+    let diffs = build_diff_log(&repo, log);
+    todo!()
+}