Add extended checksum support (#15433)

cmd/fs-v1-multipart.go

@@ -218,13 +218,13 @@ func (fs *FSObjects) ListMultipartUploads(ctx context.Context, bucket, object, k
 // subsequent request each UUID is unique.
 //
 // Implements S3 compatible initiate multipart API.
-func (fs *FSObjects) NewMultipartUpload(ctx context.Context, bucket, object string, opts ObjectOptions) (string, error) {
+func (fs *FSObjects) NewMultipartUpload(ctx context.Context, bucket, object string, opts ObjectOptions) (*NewMultipartUploadResult, error) {
 	if err := checkNewMultipartArgs(ctx, bucket, object, fs); err != nil {
-		return "", toObjectErr(err, bucket)
+		return nil, toObjectErr(err, bucket)
 	}
 
 	if _, err := fs.statBucketDir(ctx, bucket); err != nil {
-		return "", toObjectErr(err, bucket)
+		return nil, toObjectErr(err, bucket)
 	}
 
 	uploadID := mustGetUUID()
@@ -233,7 +233,7 @@ func (fs *FSObjects) NewMultipartUpload(ctx context.Context, bucket, object stri
 	err := mkdirAll(uploadIDDir, 0o755)
 	if err != nil {
 		logger.LogIf(ctx, err)
-		return "", err
+		return nil, err
 	}
 
 	// Initialize fs.json values.
@@ -243,15 +243,14 @@ func (fs *FSObjects) NewMultipartUpload(ctx context.Context, bucket, object stri
 	fsMetaBytes, err := json.Marshal(fsMeta)
 	if err != nil {
 		logger.LogIf(ctx, err)
-		return "", err
+		return nil, err
 	}
 
 	if err = ioutil.WriteFile(pathJoin(uploadIDDir, fs.metaJSONFile), fsMetaBytes, 0o666); err != nil {
 		logger.LogIf(ctx, err)
-		return "", err
+		return nil, err
 	}
-
-	return uploadID, nil
+	return &NewMultipartUploadResult{UploadID: uploadID}, nil
 }
 
 // CopyObjectPart - similar to PutObjectPart but reads data from an existing