Add filename parse and validation functions

src/machi_util.erl

@@ -34,6 +34,8 @@
          make_checksum_filename/4, make_checksum_filename/2,
          make_data_filename/4, make_data_filename/2,
          make_projection_filename/2, 
+         is_valid_filename/1,
+         parse_filename/1,
          read_max_filenum/2, increment_max_filenum/2,
          info_msg/2, verb/1, verb/2,
          mbytes/1, 
@@ -45,6 +47,8 @@
          combinations/1, ordered_combinations/1,
          mk_order/2
         ]).
+
+%% TODO: Leave this in place?
 -compile(export_all).
 
 -include("machi.hrl").
@@ -115,6 +119,32 @@ make_projection_filename(DataDir, "") ->
 make_projection_filename(DataDir, File) ->
     lists:flatten(io_lib:format("~s/projection/~s",  [DataDir, File])).
 
+%% @doc Given a filename, return true if it is a valid machi filename,
+%% false otherwise.
+-spec is_valid_filename( Filename :: string() ) -> true | false.
+is_valid_filename(Filename) ->
+    case parse_filename(Filename) of
+        [] -> false;
+        _ -> true
+    end.
+
+%% @doc Given a machi filename, return a set of components in a list.
+%% The components will be:
+%% <ul>
+%%      <li>Prefix</li>
+%%      <li>UUID</li>
+%%      <li>Sequence number</li>
+%% </ul>
+%%
+%% Invalid filenames will return an empty list.
+-spec parse_filename( Filename :: string() ) -> [ string() ].
+parse_filename(Filename) ->
+    case string:tokens(Filename, "^") of
+        [_Prefix, _UUID, _SeqNo] = L -> L;
+        _ -> []
+    end.
+
+
 %% @doc Read the file size of a config file, which is used as the
 %% basis for a minimum sequence number.