[Firebird-devel] A couple of questions about why.c and implementing database alias es

[Leyne, S. <sl...@at...>]

All,

I was doing some research about how to best implement the database alias
support and wanted to bounce some ideas of the group.  Please keep in
mind that this is a v1.0 implementation, we'll leave the much larger
discussion about the proper storage location for user security, server
parameters and other settings until a later time.

I was thinking that the appropriate place to do that was in the
GDS_DATABASE_ATTACH module of jrd\why.c, the code currently reads:

...
memcpy (temp_filename, file_name, temp_length);
temp_filename[temp_length] = '\0';

if (isc_set_path (temp_filename, org_length, expanded_filename))
    {
    temp_filename = expanded_filename;
    org_length = strlen (temp_filename);
    }
else
    ISC_expand_filename (temp_filename, org_length, expanded_filename);
...

I was thinking of creating a new fb_expand_alias procedure and adding
just before the isc_set_path call, as:

...
memcpy (temp_filename, file_name, temp_length);
temp_filename[temp_length] = '\0';

-->fb_expand_alias( temp_filename, org_length)

if (isc_set_path (temp_filename, org_length, expanded_filename))
...

This position in the attach logic would ensure that alias names are
resolved prior to the subsequent calls to the engine subsystems.

The fb_expand_alias routine would parse the filename to ensure that it
doesn't contain any punctuation.  If not, it would read the alias file
(FBAlias) and search for a matching entry.  If a match was found, the
associated filename would be returned to be processed as normal.

Comments?


Sean