[OpenSIPS-Devel] Possible bug in dbt_lib.c with suggested correction

[Michael Schloh von Bennewitz]

Hello Bogdan,

On Tues., Jan 20, 2010, Bogdan-Andrei Iancu wrote:
>Michael Schloh von Bennewitz wrote:
>> Hello list,
>>
>> It would seem that Bogdan's recent correction relating to the BLOB
>> datatype support was not complete.
>>
>> Index: modules/db_text/dbt_lib.c
>> diff -Nau modules/db_text/dbt_lib.c.orig modules/db_text/dbt_lib.c
>> --- modules/db_text/dbt_lib.c.orig	2010-01-20 11:10:07.967990871 +0100
>> +++ modules/db_text/dbt_lib.c	2010-01-20 11:10:21.649138475 +0100
>> @@ -440,7 +440,7 @@
>>  		case DB_DOUBLE:
>>  			break;
>>  		case DB_STRING:
>> -			if(_t0==DB_STR)
>> +			if(_t0==DB_STR || _t0==DB_BLOB)
>>  				return 0;
>>  		case DB_STR:
>>  			if(_t0==DB_STRING || _t0==DB_BLOB)
>>
>>
>> The '-' and '+' indicate my suggested correction, keeping in line
>> with Bogdan's recent change SVN revision 6382.
>>
>Have this fix resulted from troubleshooting some error ? or it is a
>logical fix ?
>
Your own comment for checkin 6382 is 'fixed incomatibility between
BLOB data type and string format for columns' and your change is:

--- trunk/modules/db_text/dbt_lib.c	2009/07/21 07:45:05	5901
+++ trunk/modules/db_text/dbt_lib.c	2009/12/09 16:33:12	6382
@@ -446,7 +446,7 @@
 			if(_t0==DB_STRING || _t0==DB_BLOB)
 				return 0;
 		case DB_BLOB:
-			if(_t0==DB_STR)
+			if(_t0==DB_STR || _t0==DB_STRING)
 				return 0;
 		case DB_BITMAP:
 			if (_t0==DB_INT)

That fixed a nondocumented bug in which the sip_trace module could
not write to its table when the database is dbtext.

Then I looked at the code block and saw that DB_STR and DB_STRING
are logically equal. See 'case DB_STRING: if(_t0==DB_STR) return 0;'
above.

...so I assume that if comparing DB_STR and DB_BLOB should return
0, then comparing DB_STRING and DB_BLOB should return 0 as well.
It's a long winded way of saying 'my suggestion is a logical fix.'
I've found no runtime failure to motivate this correction, although
there could be one hiding.

>Because the STRING and BLOB times are not really compatible. STRING
>is zero terminated data while BLOB contains data (including 0), if
>you get my point.
>
Just how different are DB_STRING and DB_STR? Is one zero terminated
and the other not? If that's right, then maybe the best thing is to
return 0 when comparing DB_BLOB with whichever [DB_STR|DB_STRING] is
most similar (in which zero termination plays a role in deciding.)

...and if that's how the code was in the first place, then just
disregard my patch suggestion.

Regards,
Michael

-- 
Michael Schloh von Bennewitz
http://michael.schloh.com/