Change PutMetadata to take a Metadata type instead

It's unlikely that this function is useful if it always regenerates the
metadata. Instead, the caller should do that if it needs.

backends/localfs/localfs.go

@@ -147,23 +147,7 @@ func (b LocalfsBackend) Put(key string, r io.Reader, expiry time.Time, deleteKey
 	return
 }
 
-func (b LocalfsBackend) PutMetadata(key string, r io.Reader, expiry time.Time, deleteKey string) (m backends.Metadata, err error) {
-	m, err = helpers.GenerateMetadata(r)
-	if err != nil {
-		return
-	}
-	m.Expiry = expiry
-	m.DeleteKey = deleteKey
-
-	filePath := path.Join(b.filesPath, key)
-	dst, err := os.Open(filePath)
-	if err != nil {
-		return
-	}
-	defer dst.Close()
-
-	m.ArchiveFiles, _ = helpers.ListArchiveFiles(m.Mimetype, m.Size, dst)
-
+func (b LocalfsBackend) PutMetadata(key string, m backends.Metadata) (err error) {
 	err = b.writeMetadata(key, m)
 	if err != nil {
 		return

backends/s3/s3.go

@@ -146,22 +146,12 @@ func (b S3Backend) Put(key string, r io.Reader, expiry time.Time, deleteKey stri
 	return
 }
 
-func (b S3Backend) PutMetadata(key string, r io.Reader, expiry time.Time, deleteKey string) (m backends.Metadata, err error) {
-	m, err = helpers.GenerateMetadata(r)
-	if err != nil {
-		return
-	}
-	m.Expiry = expiry
-	m.DeleteKey = deleteKey
-	// XXX: we may not be able to write this to AWS easily
-	//m.ArchiveFiles, _ = helpers.ListArchiveFiles(m.Mimetype, m.Size, tmpDst)
-
+func (b S3Backend) PutMetadata(key string, m backends.Metadata) (err error) {
 	_, err = b.svc.CopyObject(&s3.CopyObjectInput{
 		Bucket:     aws.String(b.bucket),
 		Key:        aws.String(key),
 		CopySource: aws.String("/" + b.bucket + "/" + key),
 		Metadata:   mapMetadata(m),
-
 	})
 	if err != nil {
 		return
@@ -194,7 +184,6 @@ func (b S3Backend) List() ([]string, error) {
 		return nil, err
 	}
 
-
 	for _, object := range results.Contents {
 		output = append(output, *object.Key)
 	}

backends/storage.go

@@ -12,7 +12,7 @@ type StorageBackend interface {
 	Head(key string) (Metadata, error)
 	Get(key string) (Metadata, io.ReadCloser, error)
 	Put(key string, r io.Reader, expiry time.Time, deleteKey string) (Metadata, error)
-	PutMetadata(key string, r io.Reader, expiry time.Time, deleteKey string) (Metadata, error)
+	PutMetadata(key string, m Metadata) error
 	Size(key string) (int64, error)
 }