files table needs a "module" column

Enabling an upload on for example an image node will break things: if the user uploads a file called "_original" attached to a image node, there will be two rows in the files table:

mysql> select * from files;
+-----+-----+-----------+-----------------------------+--------------------------+----------+------+
| fid | nid | filename  | filepath                    | filemime                 | filesize | list |
+-----+-----+-----------+-----------------------------+--------------------------+----------+------+
|   3 |   2 | _original | images/01_0.jpg             | image/jpeg               |   152053 |    0 |
|   4 |   2 | thumbnail | images/01_0.thumbnail-0.jpg | image/jpeg               |     2278 |    0 |
|   5 |   2 | _original | files/_original             | application/octet-stream |        0 |    1 |
+-----+-----+-----------+-----------------------------+--------------------------+----------+------+

The problem with this is that image module doesn't know anymore what file to use as its "_original" image. If it happens to use the wrong one, viewing a image node will fail (as the _original file someone uploads doesn't need to be a image file).

If a module wants to use the files table (what is suggested I think), then a module needs to have a way of saying: "what are the rows in the files table I have created? I (and I alone) know how to deal with them".

There are some solutions for this:

• all modules that use the files table use a filename as "-". Ugly!
• do a SELECT * FROM {files} WHERE filemime LIKE 'image/%'. This works for image module (probably) but is not general.
• Add a "module" column (or "owner" I'm not sure of the convention in other tables).

This way a module can figure out what files it should handle and what files to leave alone.

What do you think?