Add multipart support in SSE-C encryption (#5576)

*) Add Put/Get support of multipart in encryption
*) Add GET Range support for encryption
*) Add CopyPart encrypted support
*) Support decrypting of large single PUT object

cmd/xl-v1-object.go

@@ -395,26 +395,7 @@ func (xl xlObjects) getObjectInfo(bucket, object string) (objInfo ObjectInfo, er
 		return objInfo, err
 	}
 
-	objInfo = ObjectInfo{
-		IsDir:           false,
-		Bucket:          bucket,
-		Name:            object,
-		Size:            xlMeta.Stat.Size,
-		ModTime:         xlMeta.Stat.ModTime,
-		ContentType:     xlMeta.Meta["content-type"],
-		ContentEncoding: xlMeta.Meta["content-encoding"],
-	}
-
-	// Extract etag.
-	objInfo.ETag = extractETag(xlMeta.Meta)
-
-	// etag/md5Sum has already been extracted. We need to
-	// remove to avoid it from appearing as part of
-	// response headers. e.g, X-Minio-* or X-Amz-*.
-	objInfo.UserDefined = cleanMetadata(xlMeta.Meta)
-
-	// Success.
-	return objInfo, nil
+	return xlMeta.ToObjectInfo(bucket, object), nil
 }
 
 func undoRename(disks []StorageAPI, srcBucket, srcEntry, dstBucket, dstEntry string, isDir bool, errs []error) {