Re: [PATCH] Turn apr_table_t into a hash table

[Brian Pane]

Ryan Bloom wrote:
The latter.  Having two API's to the same functions should only be done
as a stop-gap.
I disagree.  It's inevitable to have two APIs, as long as we have two
'table' types with very different semantics.
apr_table_t is statically typed (uses char*), and apr_hash_t isn't (uses
void*).
If we did a direct replacement of apr_table_t with apr_hash_t in the httpd,
we'd be sacrificing static type-safety for a lot of code.
So create a simple set of prototypes and macros for a char * version of the
hash code, the same way we did for ap_strchr and ap_strchr_c.  If you do
that, you will be adding probably two or three new functions to APR.\
Yes, macro wrappers would work.  But if we use that approach, it would
be advantageous to use macro names like "apr_table_get" so that all
the existing httpd code and 3rd party modules can be used without 
modification.
This would be functionally equivalent to the "implement apr_table_t using
apr_hash_t" approach that I prefer.

Also, a LOT of modules using the apr_table_elem macro
to get the elements from a table.  Turning that into an API would break a
lot of people.
My patch covers all the changes needed for the core modules.  Do you have
any info on the number of 3rd-party modules for 2.0 that use
apr_table_elem?
The core is not the only set of modules for Apache.  Did you look at 
mod_perl,
php, tomcat?
mod_perl and Tomcat (mod_jk) don't use apr_table_elts.  PHP contains two 
calls to it.

 I don't know if any of them use this feature or not, but they aren't
a part of the core.  Did you look at all of the modules in modules.apache.org, 
or
freshmeat?  I know that there aren't many modules for 2.0 today, but at some
point, everybody who has a module for 1.3 will want to port it to 2.0.  I can
currently do that in under one hour for even complex modules.  Changing API's
like this after we have had 25 releases, makes that harder.
Based on how infrequently apr_table_elts is used in the core and in PHP and
mod_perl, and how small the code change required to use the iterator API is,
I'd be extremely surprised if the removal of apr_table_elts substantially
impaired one's ability to port a module from 1.3 to 2.0 in under an hour.
--Brian