1 files changed, 94 insertions, 0 deletions
diff --git a/modules/lfs/content_store.go b/modules/lfs/content_store.go
new file mode 100644
index 0000000000..2ca44512f1
--- /dev/null
+++ b/modules/lfs/content_store.go
@@ -0,0 +1,94 @@
+package lfs
+
+import (
+	"code.gitea.io/gitea/models"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+var (
+	errHashMismatch = errors.New("Content hash does not match OID")
+	errSizeMismatch = errors.New("Content size does not match")
+)
+
+// ContentStore provides a simple file system based storage.
+type ContentStore struct {
+	BasePath string
+}
+
+// Get takes a Meta object and retreives the content from the store, returning
+// it as an io.Reader. If fromByte > 0, the reader starts from that byte
+func (s *ContentStore) Get(meta *models.LFSMetaObject, fromByte int64) (io.ReadCloser, error) {
+	path := filepath.Join(s.BasePath, transformKey(meta.Oid))
+
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	if fromByte > 0 {
+		_, err = f.Seek(fromByte, os.SEEK_CUR)
+	}
+	return f, err
+}
+
+// Put takes a Meta object and an io.Reader and writes the content to the store.
+func (s *ContentStore) Put(meta *models.LFSMetaObject, r io.Reader) error {
+	path := filepath.Join(s.BasePath, transformKey(meta.Oid))
+	tmpPath := path + ".tmp"
+
+	dir := filepath.Dir(path)
+	if err := os.MkdirAll(dir, 0750); err != nil {
+		return err
+	}
+
+	file, err := os.OpenFile(tmpPath, os.O_CREATE|os.O_WRONLY|os.O_EXCL, 0640)
+	if err != nil {
+		return err
+	}
+	defer os.Remove(tmpPath)
+
+	hash := sha256.New()
+	hw := io.MultiWriter(hash, file)
+
+	written, err := io.Copy(hw, r)
+	if err != nil {
+		file.Close()
+		return err
+	}
+	file.Close()
+
+	if written != meta.Size {
+		return errSizeMismatch
+	}
+
+	shaStr := hex.EncodeToString(hash.Sum(nil))
+	if shaStr != meta.Oid {
+		return errHashMismatch
+	}
+
+	if err := os.Rename(tmpPath, path); err != nil {
+		return err
+	}
+	return nil
+}
+
+// Exists returns true if the object exists in the content store.
+func (s *ContentStore) Exists(meta *models.LFSMetaObject) bool {
+	path := filepath.Join(s.BasePath, transformKey(meta.Oid))
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return false
+	}
+	return true
+}
+
+func transformKey(key string) string {
+	if len(key) < 5 {
+		return key
+	}
+
+	return filepath.Join(key[0:2], key[2:4], key[4:len(key)])
+}