1 files changed, 90 insertions, 0 deletions
diff --git a/plumbing/object/commitgraph/commitnode_object.go b/plumbing/object/commitgraph/commitnode_object.go
new file mode 100644
index 0000000..2779a54
--- /dev/null
+++ b/plumbing/object/commitgraph/commitnode_object.go
@@ -0,0 +1,90 @@
+package commitgraph
+
+import (
+	"math"
+	"time"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/object"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
+)
+
+// objectCommitNode is a representation of Commit as presented in the GIT object format.
+//
+// objectCommitNode implements the CommitNode interface.
+type objectCommitNode struct {
+	nodeIndex CommitNodeIndex
+	commit    *object.Commit
+}
+
+// NewObjectCommitNodeIndex returns CommitNodeIndex implementation that uses
+// only object storage to load the nodes
+func NewObjectCommitNodeIndex(s storer.EncodedObjectStorer) CommitNodeIndex {
+	return &objectCommitNodeIndex{s}
+}
+
+func (oci *objectCommitNodeIndex) Get(hash plumbing.Hash) (CommitNode, error) {
+	commit, err := object.GetCommit(oci.s, hash)
+	if err != nil {
+		return nil, err
+	}
+
+	return &objectCommitNode{
+		nodeIndex: oci,
+		commit:    commit,
+	}, nil
+}
+
+// objectCommitNodeIndex is an index that can load CommitNode objects only from the
+// object store.
+//
+// objectCommitNodeIndex implements the CommitNodeIndex interface
+type objectCommitNodeIndex struct {
+	s storer.EncodedObjectStorer
+}
+
+func (c *objectCommitNode) CommitTime() time.Time {
+	return c.commit.Committer.When
+}
+
+func (c *objectCommitNode) ID() plumbing.Hash {
+	return c.commit.ID()
+}
+
+func (c *objectCommitNode) Tree() (*object.Tree, error) {
+	return c.commit.Tree()
+}
+
+func (c *objectCommitNode) NumParents() int {
+	return c.commit.NumParents()
+}
+
+func (c *objectCommitNode) ParentNodes() CommitNodeIter {
+	return newParentgraphCommitNodeIter(c)
+}
+
+func (c *objectCommitNode) ParentNode(i int) (CommitNode, error) {
+	if i < 0 || i >= len(c.commit.ParentHashes) {
+		return nil, object.ErrParentNotFound
+	}
+
+	// Note: It's necessary to go through CommitNodeIndex here to ensure
+	// that if the commit-graph file covers only part of the history we
+	// start using it when that part is reached.
+	return c.nodeIndex.Get(c.commit.ParentHashes[i])
+}
+
+func (c *objectCommitNode) ParentHashes() []plumbing.Hash {
+	return c.commit.ParentHashes
+}
+
+func (c *objectCommitNode) Generation() uint64 {
+	// Commit nodes representing objects outside of the commit graph can never
+	// be reached by objects from the commit-graph thus we return the highest
+	// possible value.
+	return math.MaxUint64
+}
+
+func (c *objectCommitNode) Commit() (*object.Commit, error) {
+	return c.commit, nil
+}