Package gitobj reads and writes loose and packed Git objects.

To access a repository's objects, begin by "opening" that repository for use:

package main
import (
	"github.com/git-lfs/gitobj"
)
func main() {
	repo, err := gitobj.FromFilesystem("/path/to/repo.git", "")
	if err != nil {
		panic(err)
	}
	defer repo.Close()
}

You can then open objects for inspection with the Blob(), Commit(), Tag(), or Tree() functions:

func main() {
	repo, err := gitobj.FromFilesystem("/path/to/repo.git", "")
	if err != nil {
		panic(err)
	}
	defer repo.Close()
	commit, err := repo.Commit([]byte{...})
	if err != nil {
		panic(err)
	}
}

Once an object is opened or an instance is held, it can be saved to the object database using the WriteBlob(), WriteCommit(), WriteTag(), or WriteTree() functions:

func main() {
	repo, err := gitobj.FromFilesystem("/path/to/repo.git", "")
	if err != nil {
		panic(err)
	}
	defer repo.Close()
	commit, err := repo.Commit([]byte{...})
	if err != nil {
		panic(err)
	}
	commit.Message = "Hello from gitobj!"
	commit.ExtraHeaders = append(commit.ExtraHeaders, &gitobj.ExtraHeader{
		K: "Signed-off-by",
		V: "Jane Doe <jane@example.com>",
	})
	if _, err := repository.WriteCommit(commit); err != nil {
		panic(err)
	}
}

Package gitobj has support for reading "packed" objects (i.e., objects found in packfiles) via package github.com/git-lfs/gitobj/pack. Package pack implements searching pack index (.idx) files and locating the corresponding delta-base chain in the appropriate pack file. It understands both version 1 and version 2 of the packfile specification.

gitobj will always try to locate a loose object first. If a loose object cannot be found with the appropriate SHA-1, the repository's packfile(s) will be searched. If an object is located in a packfile, that object will be reconstructed along its delta-base chain and then returned transparently.

For more: https://godoc.org/github.com/git-lfs/gitobj.

MIT.