Fix for bug 824 - proper handling of REG_MULTI_SZ

[Randy Galbraith]

Alexandre Julliard wrote:

>"Dimitrie O. Paun" <dpaun at rogers.com> writes:
>
>  
>
>>I must be missing something, but I thought regular strings can not
>>contain embedded nulls, so we can have a simple rule: don't store
>>terminating nulls for simple strings, but store them for multi-strings.
>><me-thinks>
>>Aha -- you mean that if we follow this rule, all is good, but we
>>will not be backwards compatible because currently multi-strings
>>don't have the embedded nulls, right?
>>    
>>
>
>Right; though the problem happens for regular strings too, they don't
>necessarily have to be null terminated. And of course it would require
>everybody editing the file to always remember to add terminating
>nulls, which is much less user-friendly than what we have now.
>
>  
>
>>In that case, I guess we already have a versioning mechanism for
>>the registry files, so we'll just have to go to the next version,
>>and convert the old files to the new format.
>>    
>>
>
>That's a major PITA, certainly not justified for such a minor problem
>that hasn't been demonstrated to cause any trouble in practice.
>
>  
>
What does PITA stand for?

I assumed bug 824 was on the "tasklets" list because it was a 
requirement for Wine 0.9 and/or 1.0.  Going back to the original 
comments the complaint was Wine's instance on storing the last \0 
regardless.  Hence certain REG_MULTI_SZ values can not be reliably 
stored and retrieved...

hex(7): <-- length = 0
hex(7):01 <-- length = 1

They come out as:

hex(7):00
hex(7):01,00

Of course inside user.reg Wine has stored...

=str(7):""
=str(7):"\1"

The only way I can see of satisfying the requirements for readability & 
editability would be to explicitly store the length of multi-strings 
thusly...

=str(7),len=0:""
=str(7),len=1:"\1"

Yet still allow for an implied length when one was not supplied, such as....

=str(7):"one\0two\0three\0"

Of course this raises the question of what to do when length and data 
conflict...

=str(7),len=20:"small\0"

Alas, no easy answers it would seem :(

Kind regards,
-Randy Galbraith