func ExtractTree(repo git.Repo, branch, build_dir string) error {
// resolve branch
hash, err := repo.ReadRef(branch)
if err != nil {
return err
}
if _, err := os.Stat(build_dir); os.IsNotExist(err) {
os.MkdirAll(build_dir, 0777)
}
// read commit object and extract tree id from it
_, obj, err := repo.OpenObject(hash)
if err != nil {
return err
}
defer obj.Close()
commit, err := git.ReadCommit(obj)
if err != nil {
return err
}
treeId := commit.TreeId
// read root tree object
_, treeObj, err := repo.OpenObject(treeId)
if err != nil {
return err
}
defer treeObj.Close()
root, err := git.ReadTree(treeObj)
if err != nil {
return err
}
// traverse tree from root and extract content into given directory
err = traverseExtractTree(repo, root, build_dir)
if err != nil {
return err
}
return nil
}
