Tom Lane wrote:
> Andrew Chernow <ac@esilo.com> writes:
>>>> What parts of PGconn/PGresult do you need to touch that aren't exposed
>>>> already?
>
>> Don't need direct access to PGconn at all.
>
> Oh, good, that makes things much easier.
>
Shoot! Feels like you always miss something.
The patch uses PGconn's PQExpBuffer to set errors on a conn. Currently,
there is no access to this buffer other than PQerrorMessage. Is the
below okay?
extern PQExpBuffer *PQgetErrorBuffer(PGconn *conn);
// OR PQsetErrorMessage(conn, errstr) -- this felt strange to me
The expbuffer API is public, so managing the returned PQExpBuffer would
not require any additional API calls.
While I am on the subject of things I missed, the patch also uses
pqSetResultError (mostly during PQgetf).
We no longer need direct access to anything inside pg_result. However,
we would need 3 new API calls that would dup a result, set field descs
and add tuples to a result. Below are prototypes of what I have so far
(small footprint for all 3, maybe 100-150 lines).
/* numParameters, paramDescs, errFields, curBlock, * curOffset and spaceLeft are not assigned at all, * initialized to
zero. errMsg is handled by * PQmakeEmptyPGresult. attDescs and tuples are not * duplicated, only allocated based on
'ntups'and * 'numAttributes'. The idea is to dup the result * but customize attDescs and tuples. */
PGresult *PQresultDup( PGconn *conn, PGresult *source, int ntups, int numAttributes);
/* Only for results returned by PQresultDup. This * will set the field descs for 'field_num'. The * PGresAttDesc
structwas not used to avoid * exposing it. */
int PQresultSetFieldDesc( PGresult *res, int field_num, const char *name, Oid tableid, int columnid, int format,
Oidtypid, int typlen, int typmod)
/* Only for results returned by PQresultDup. This * will append a new tuple to res. A PGresAttValue * is allocated
andput at index 'res->ntups'. This * is similar to pqAddTuple except that the tuples * table has been pre-allocated.
Inour case, ntups * and numAttributes are known when calling resultDup. */
int PQresultAddTuple( PGresult *res, char *value, int len);
The above would allow an external app to dup a result and customize its
rows and columns. Our patch uses this for arrays and composites.
--
Andrew Chernow
eSilo, LLC
every bit counts
http://www.esilo.com/
