Add repo_blob

This adds a new repo.GetBlob(id) method for use by gitea.

Author: clee

repo_blob.go

@@ -0,0 +1,30 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package git
+
+func (repo *Repository) getBlob(id SHA1) (*Blob, error) {
+	if _, err := NewCommand("cat-file", "-p", id.String()).RunInDir(repo.Path); err != nil {
+		return nil, ErrNotExist{id.String(), ""}
+	}
+
+	return &Blob{
+		repo: repo,
+		TreeEntry: &TreeEntry{
+			ID: id,
+			ptree: &Tree{
+				repo: repo,
+			},
+		},
+	}, nil
+}
+
+// GetBlob finds the blob object in the repository.
+func (repo *Repository) GetBlob(idStr string) (*Blob, error) {
+	id, err := NewIDFromString(idStr)
+	if err != nil {
+		return nil, err
+	}
+	return repo.getBlob(id)
+}