1 files changed, 243 insertions, 0 deletions
diff --git a/worktree_commit.go b/worktree_commit.go
new file mode 100644
index 0000000..bec75b2
--- /dev/null
+++ b/worktree_commit.go
@@ -0,0 +1,243 @@
+package git
+
+import (
+	"io"
+	"path/filepath"
+	"strings"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/filemode"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/index"
+	"gopkg.in/src-d/go-git.v4/plumbing/object"
+	"gopkg.in/src-d/go-git.v4/storage"
+	"gopkg.in/src-d/go-git.v4/utils/ioutil"
+
+	"gopkg.in/src-d/go-billy.v2"
+)
+
+// Commit stores the current contents of the index in a new commit along with
+// a log message from the user describing the changes.
+func (w *Worktree) Commit(msg string, opts *CommitOptions) (plumbing.Hash, error) {
+	if err := opts.Validate(w.r); err != nil {
+		return plumbing.ZeroHash, err
+	}
+
+	if opts.All {
+		if err := w.autoAddModifiedAndDeleted(); err != nil {
+			return plumbing.ZeroHash, err
+		}
+	}
+
+	idx, err := w.r.Storer.Index()
+	if err != nil {
+		return plumbing.ZeroHash, err
+	}
+
+	h := &commitIndexHelper{
+		fs: w.fs,
+		s:  w.r.Storer,
+	}
+
+	tree, err := h.buildTreeAndBlobObjects(idx)
+	if err != nil {
+		return plumbing.ZeroHash, err
+	}
+
+	commit, err := w.buildCommitObject(msg, opts, tree)
+	if err != nil {
+		return plumbing.ZeroHash, err
+	}
+
+	return commit, w.updateHEAD(commit)
+}
+
+func (w *Worktree) autoAddModifiedAndDeleted() error {
+	s, err := w.Status()
+	if err != nil {
+		return err
+	}
+
+	for path, fs := range s {
+		if fs.Worktree != Modified && fs.Worktree != Deleted {
+			continue
+		}
+
+		if _, err := w.Add(path); err != nil {
+			return err
+		}
+
+	}
+
+	return nil
+}
+
+func (w *Worktree) updateHEAD(commit plumbing.Hash) error {
+	head, err := w.r.Storer.Reference(plumbing.HEAD)
+	if err != nil {
+		return err
+	}
+
+	name := plumbing.HEAD
+	if head.Type() != plumbing.HashReference {
+		name = head.Target()
+	}
+
+	ref := plumbing.NewHashReference(name, commit)
+	return w.r.Storer.SetReference(ref)
+}
+
+func (w *Worktree) buildCommitObject(msg string, opts *CommitOptions, tree plumbing.Hash) (plumbing.Hash, error) {
+	commit := &object.Commit{
+		Author:       *opts.Author,
+		Committer:    *opts.Committer,
+		Message:      msg,
+		TreeHash:     tree,
+		ParentHashes: opts.Parents,
+	}
+
+	obj := w.r.Storer.NewEncodedObject()
+	if err := commit.Encode(obj); err != nil {
+		return plumbing.ZeroHash, err
+	}
+	return w.r.Storer.SetEncodedObject(obj)
+}
+
+// commitIndexHelper converts a given index.Index file into multiple git objects
+// reading the blobs from the given filesystem and creating the trees from the
+// index structure. The created objects are pushed to a given Storer.
+type commitIndexHelper struct {
+	fs billy.Filesystem
+	s  storage.Storer
+
+	trees   map[string]*object.Tree
+	entries map[string]*object.TreeEntry
+}
+
+// buildTreesAndBlobs builds the objects and push its to the storer, the hash
+// of the root tree is returned.
+func (h *commitIndexHelper) buildTreeAndBlobObjects(idx *index.Index) (plumbing.Hash, error) {
+	const rootNode = ""
+	h.trees = map[string]*object.Tree{rootNode: {}}
+	h.entries = map[string]*object.TreeEntry{}
+
+	for _, e := range idx.Entries {
+		if err := h.commitIndexEntry(e); err != nil {
+			return plumbing.ZeroHash, err
+		}
+	}
+
+	return h.copyTreeToStorageRecursive(rootNode, h.trees[rootNode])
+}
+
+func (h *commitIndexHelper) commitIndexEntry(e *index.Entry) error {
+	parts := strings.Split(e.Name, string(filepath.Separator))
+
+	var path string
+	for _, part := range parts {
+		parent := path
+		path = filepath.Join(path, part)
+
+		if !h.buildTree(e, parent, path) {
+			continue
+		}
+
+		if err := h.copyIndexEntryToStorage(e); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (h *commitIndexHelper) buildTree(e *index.Entry, parent, path string) bool {
+	if _, ok := h.trees[path]; ok {
+		return false
+	}
+
+	if _, ok := h.entries[path]; ok {
+		return false
+	}
+
+	te := object.TreeEntry{Name: filepath.Base(path)}
+
+	if path == e.Name {
+		te.Mode = e.Mode
+		te.Hash = e.Hash
+	} else {
+		te.Mode = filemode.Dir
+		h.trees[path] = &object.Tree{}
+	}
+
+	h.trees[parent].Entries = append(h.trees[parent].Entries, te)
+	return true
+}
+
+func (h *commitIndexHelper) copyIndexEntryToStorage(e *index.Entry) error {
+	_, err := h.s.EncodedObject(plumbing.BlobObject, e.Hash)
+	if err == nil {
+		return nil
+	}
+
+	if err != plumbing.ErrObjectNotFound {
+		return err
+	}
+
+	return h.doCopyIndexEntryToStorage(e)
+}
+
+func (h *commitIndexHelper) doCopyIndexEntryToStorage(e *index.Entry) (err error) {
+	fi, err := h.fs.Stat(e.Name)
+	if err != nil {
+		return err
+	}
+
+	obj := h.s.NewEncodedObject()
+	obj.SetType(plumbing.BlobObject)
+	obj.SetSize(fi.Size())
+
+	reader, err := h.fs.Open(e.Name)
+	if err != nil {
+		return err
+	}
+
+	defer ioutil.CheckClose(reader, &err)
+
+	writer, err := obj.Writer()
+	if err != nil {
+		return err
+	}
+
+	defer ioutil.CheckClose(writer, &err)
+
+	if _, err := io.Copy(writer, reader); err != nil {
+		return err
+	}
+
+	_, err = h.s.SetEncodedObject(obj)
+	return err
+}
+
+func (h *commitIndexHelper) copyTreeToStorageRecursive(parent string, t *object.Tree) (plumbing.Hash, error) {
+	for i, e := range t.Entries {
+		if e.Mode != filemode.Dir && !e.Hash.IsZero() {
+			continue
+		}
+
+		path := filepath.Join(parent, e.Name)
+
+		var err error
+		e.Hash, err = h.copyTreeToStorageRecursive(path, h.trees[path])
+		if err != nil {
+			return plumbing.ZeroHash, err
+		}
+
+		t.Entries[i] = e
+	}
+
+	o := h.s.NewEncodedObject()
+	if err := t.Encode(o); err != nil {
+		return plumbing.ZeroHash, err
+	}
+
+	return h.s.SetEncodedObject(o)
+}