2 files changed, 100 insertions, 0 deletions
diff --git a/users/Profpatsch/git-db/default.nix b/users/Profpatsch/git-db/default.nix
new file mode 100644
index 000000000000..ad5d927677bf
--- /dev/null
+++ b/users/Profpatsch/git-db/default.nix
@@ -0,0 +1,10 @@
+{ depot, pkgs, lib, ... }:
+
+depot.nix.writers.rustSimple
+{
+  name = "git-db";
+  dependencies = [
+    depot.third_party.rust-crates.git2
+  ];
+}
+  (builtins.readFile ./git-db.rs)
diff --git a/users/Profpatsch/git-db/git-db.rs b/users/Profpatsch/git-db/git-db.rs
new file mode 100644
index 000000000000..c8019bf03661
--- /dev/null
+++ b/users/Profpatsch/git-db/git-db.rs
@@ -0,0 +1,90 @@
+extern crate git2;
+use std::os::unix::ffi::OsStrExt;
+use std::path::PathBuf;
+
+const DEFAULT_BRANCH: &str = "refs/heads/main";
+
+fn main() {
+    let git_db_dir = std::env::var_os("GIT_DB_DIR").expect("set GIT_DB_DIR");
+    let git_db = PathBuf::from(git_db_dir).join("git");
+
+    std::fs::create_dir_all(&git_db).unwrap();
+
+    let repo = git2::Repository::init_opts(
+        &git_db,
+        git2::RepositoryInitOptions::new()
+            .bare(true)
+            .mkpath(true)
+            .description("git-db database")
+            .initial_head(DEFAULT_BRANCH),
+    )
+    .expect(&format!(
+        "unable to create or open bare git repo at {}",
+        &git_db.display()
+    ));
+
+    let mut index = repo.index().expect("cannot get the git index file");
+    eprintln!("{:#?}", index.version());
+    index.clear().expect("could not clean the index");
+
+    let now = std::time::SystemTime::now()
+        .duration_since(std::time::SystemTime::UNIX_EPOCH)
+        .expect("unable to get system time");
+
+    let now_git_time = git2::IndexTime::new(
+        now.as_secs() as i32, // lol
+        u32::from(now.subsec_nanos()),
+    );
+
+    let data = "hi, it’s me".as_bytes();
+
+    index
+        .add_frombuffer(
+            &git2::IndexEntry {
+            mtime: now_git_time,
+            ctime: now_git_time,
+            // don’t make sense
+            dev: 0,
+            ino: 0,
+            mode: /*libc::S_ISREG*/ 0b1000 << (3+9) | /* read write for owner */ 0o644,
+            uid: 0,
+            gid: 0,
+            file_size: data.len() as u32, // lol again
+            id: git2::Oid::zero(),
+            flags: 0,
+            flags_extended: 0,
+            path: "hi.txt".as_bytes().to_owned(),
+        },
+            data,
+        )
+        .expect("could not add data to index");
+
+    let oid = index.write_tree().expect("could not write index tree");
+
+    let to_add_tree = repo
+        .find_tree(oid)
+        .expect("we just created this tree, where did it go?");
+
+    let parent_commits = match repo.find_reference(DEFAULT_BRANCH) {
+        Ok(ref_) => vec![ref_.peel_to_commit().expect(&format!(
+            "reference {} does not point to a commit",
+            DEFAULT_BRANCH
+        ))],
+        Err(err) => match err.code() {
+            // no commit exists yet
+            git2::ErrorCode::NotFound => vec![],
+            _ => panic!("could not read latest commit from {}", DEFAULT_BRANCH),
+        },
+    };
+    repo.commit(
+        Some(DEFAULT_BRANCH),
+        &git2::Signature::now("Mr. Authorboy", "author@example.com").unwrap(),
+        &git2::Signature::now("Mr. Commiterboy", "committer@example.com").unwrap(),
+        "This is my first commit!\n\
+         \n\
+         I wonder if it supports extended commit descriptions?\n",
+        &to_add_tree,
+        &parent_commits.iter().collect::<Vec<_>>()[..],
+    )
+    .expect("could not commit the index we just wrote");
+}