Subject: Re: [PATCH v3 2/3] config: add hashtable for config parsing & retrieval

From: Karsten Blees <[email-masked]>
Date: Fri, 27 Jun 2014 10:19:32 +0200

Am 26.06.2014 23:21, schrieb Junio C Hamano:
> Karsten Blees <[email-masked]> writes:
> 
>>> Because I had an experience under my belt of a painful refactoring
>>> of "the_index" which turned out to be not just a single array, I
>>> simply suspect that the final data structure to represent a "set of
>>> config-like things" will not be just a single hashmap, hence I do
>>> prefer to have one layer of abstraction "struct config_set", which
>>> would contain a hashmap and possibly more.  Doesn't "is the hashmap
>>> initialized" bit belong there, for example?
>>
>> Would an additional
>>
>>   int hashmap_is_initialized(constr struct hashmap *map)
>>   {
>>     return !!map->table;
>>   }
>>
>> API help? (Note that hashmap_free() already does memset(0), so the
>> usual notion of "zero memory means unitialized" applies).
> 
> It may remove the need for the separate "hashmap_initialized" bit
> that was implemented as a file-scope global in the patch.
> 

That the variable is redundant was all I was trying to say, sorry for
the misunderstanding. But reading through api-hashmap.txt again, I
found that documentation of the hashmap members is pretty vague, so
perhaps improving the docs would suffice (e.g. "hashmap.table != NULL
indicates the hashmap has been initialized.").

> I however am not convinced that it will be the _only_ thing other
> than the hashmap we would need to use to keep track of the in-core
> "set of config-like things", and usually a blanket statement "these
> are the only thing we would ever need" tends not to hold for long,
> so...
>

I think having an extra type for the configuration is a Good Thing
(even if the only member is a hashmap). Although I wouldn't call it
'config_set', as it conflicts with the verb 'set', resulting in
weird APIs ('config_set_get_value()', 'config_set_set_value()').
Perhaps 'config_map' or 'config_settings', or just 'config'?