Re: Filename guarantees

[Earl Hood <ehood@hydra.acs.uci.edu>]

On January 15, 2002 at 20:43, J C Lawrence wrote:

> Currently, no matter how many messages you add to the end MH folder
> store, the matching MHonArc archive will always assign the same
> filenames to the same messages.  This seems reasonable as well as
> extremely useful (it means I can re-gen archives and have all the
> external links to individual messages not break), but can I rely on
> this?  I'm about to start some large architectural changes to my
> site and archives which may result in the archives being regenned
> fairly frequently (long story).
> 
> Can I reasonably rely on the msg->filename mapping always being
> constant remaining true?

Depends on how the data gets fed into mhonarc.

For MH directories, If any single file in the directory is deleted,
then archive re-creation will have different message numbers for those
message files with a larger numbered filename from the one deleted.
For example, say you had the following files in your MH directory:

	1
	2
	3
	4
	5

If the directory is passed into MHonArc, the following MHonArc message
numbers will be assigned to them:

	1 => 00000
	2 => 00001
	3 => 00002
	4 => 00003
	5 => 00004

If you delete message 3 from the MH directory, and recreate the
MHonArc archive, you would get:

	1 => 00000
	2 => 00001
	4 => 00002
	5 => 00003


If you will be using the same MH directories as input, and you have
not deleted any files, you should get the same numbers assigned for
each message.

--ewh