pull and (TODO) build and (TODO) push

src/build.rs

@@ -0,0 +1,52 @@
+use anyhow::{Error, Result};
+use git2::BranchType;
+
+use crate::config::RepoConfig;
+
+pub fn pull_or_clone_and_build_and_push(repo: &RepoConfig) -> Result<(), BuildError> {
+    let git_repo = pull_or_clone(repo)?;
+    build(&git_repo)?;
+    push(&git_repo)?;
+
+    Ok(())
+}
+
+fn pull_or_clone(repo: &RepoConfig) -> Result<git2::Repository, BuildError> {
+    match git2::Repository::open(&repo.local_git_repo) {
+        Ok(git_repo) => {
+            pull(&git_repo).map_err(|err| BuildError::FailedToPull(err))?;
+            Ok(git_repo)
+        },
+
+        Err(open_err) =>  match git2::Repository::clone(&repo.remote_git_repo, &repo.local_git_repo) {
+            Ok(git_repo) => Ok(git_repo),
+            Err(clone_err) => Err(BuildError::FailedToOpenOrClone(open_err.into(), clone_err.into())),
+        }
+    }
+}
+
+fn build(git_repo: &git2::Repository) -> Result<(), BuildError> {
+    todo!()
+}
+
+fn push(git_repo: &git2::Repository) -> Result<(), BuildError> {
+    todo!()
+}
+
+fn pull(git_repo: &git2::Repository) -> Result<()> {
+    let mut origin = git_repo.find_remote("origin")?;
+    let (main_branch, main_branch_name) = git_repo.find_branch("main", BranchType::Local).map(|b| (b, "main"))
+        .or_else(|_| git_repo.find_branch("master", BranchType::Local).map(|b| (b, "master")))?;
+    let upstream_main_branch = main_branch.upstream()?;
+
+    git_repo.set_head(main_branch_name)?;
+    origin.fetch(&[main_branch_name], None, None)?;
+    let upstream_commit = git_repo.reference_to_annotated_commit(&upstream_main_branch.into_reference())?;
+    git_repo.merge(&[&upstream_commit], None, None)?;
+    Ok(())
+}
+
+pub enum BuildError {
+    FailedToOpenOrClone(Error, Error),
+    FailedToPull(Error),
+}