Use GetObjectNInfo in CopyObject and CopyObjectPart (#6489)

cmd/copy-part-range.go

@@ -68,3 +68,29 @@ func parseCopyPartRange(rangeString string, resourceSize int64) (offset, length
 
 	return hrange.GetOffsetLength(resourceSize)
 }
+
+// parseCopyPartRangeSpec transforms a range string (e.g. bytes=3-4) to HTTPRangeSpec
+// and returns errors if weird values
+func parseCopyPartRangeSpec(rangeString string) (hrange *HTTPRangeSpec, err error) {
+	hrange, err = parseRequestRangeSpec(rangeString)
+	if err != nil {
+		return nil, err
+	}
+	if hrange.IsSuffixLength || hrange.Start < 0 || hrange.End < 0 {
+		return nil, errInvalidRange
+	}
+	return hrange, nil
+}
+
+// checkCopyPartRangeWithSize adds more check to the range string in case of
+// copy object part. This API requires having specific start and end  range values
+// e.g. 'bytes=3-10'. Other use cases will be rejected.
+func checkCopyPartRangeWithSize(rs *HTTPRangeSpec, resourceSize int64) (err error) {
+	if rs == nil {
+		return nil
+	}
+	if rs.IsSuffixLength || rs.Start >= resourceSize || rs.End >= resourceSize {
+		return errInvalidRangeSource
+	}
+	return nil
+}