URL Managment - C Function help

Samuel ROZE <samuel.roze@gmail.com> writes:

The problem is that they don't work fine... :/

I think the problem is that you are passing C strings to code that
expects pointers to text datums --- which are not the same thing
at all. (text has a length word, not a null terminator byte.)
It's pure accident that your first example works, and entirely
unsurprising that the second one doesn't. Some CStringGetTextDatum
calls might help.

regards, tom lane

Samuel ROZE wrote:

PG_FUNCTION_INFO_V1(parse_url_record);
Datum parse_url_record (PG_FUNCTION_ARGS)
{
// Vars about the params
//text *str2 = PG_GETARG_TEXT_P(0);
char str[] = "http://www.ovh.com/intenal.html&quot;;

// Some vars which will used to create the composite output type
TupleDesc tupdesc;
Datum values[2]; // 8 values
HeapTuple tuple;
bool nulls[2];
int tuplen;

// Check NULLs values
if(PG_ARGISNULL(0) || PG_ARGISNULL(1)) {
PG_RETURN_NULL();
}

url *ret = parse_url_exec(str);

// Add datas into the values Datum
values[0] = PointerGetDatum(ret->scheme);
values[1] = PointerGetDatum(ret->host);

// Convert values into a composite type
/*tuplen = tupdesc->natts;
nulls = palloc(tuplen * sizeof(bool));*/
memset(nulls, 0, sizeof(nulls));

// build tuple from datum array
tuple = heap_form_tuple(tupdesc, values, nulls);
// Free null values
/*pfree(nulls);*/

// Return the composite type
PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
}

You haven't initialized tupdesc.

BTW, there's a fine example in the manual:
http://www.postgresql.org/docs/8.4/interactive/xfunc-c.html#AEN44968

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com

Thanks for your reply.

--------------------------------------------------------
PG_FUNCTION_INFO_V1(parse_url_record);
Datum parse_url_record (PG_FUNCTION_ARGS)
{
// Vars about the params
//text *str2 = PG_GETARG_TEXT_P(0);
char str[] = "http://www.ovh.com/intenal.html&quot;;

// Some vars which will used to create the composite output type
TupleDesc tupdesc;
char **values;
HeapTuple tuple;
AttInMetadata *attinmeta;
bool nulls[2];
int tuplen;

// Check NULLs values
if(PG_ARGISNULL(0) || PG_ARGISNULL(1)) {
PG_RETURN_NULL();
}

url *ret = parse_url_exec(str);

if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context "
"that cannot accept type record")));
}
attinmeta = TupleDescGetAttInMetadata(tupdesc);

// ...
values = (char **) palloc(2 * sizeof(char *));

// Add datas into the values Datum
values[0] = (char *) ret->scheme;
values[1] = (char *) ret->host;

// Convert values into a composite type
memset(nulls, 0, sizeof(nulls));

// build tuple from datum array
tuple = BuildTupleFromCStrings(attinmeta, values);

// Return the composite type
PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
}
-------------------------------------------------------

This code doesn't works better... :/

Le mercredi 21 octobre 2009 à 18:42 +0300, Heikki Linnakangas a écrit :

Le mercredi 21 octobre 2009 à 11:42 -0400, Tom Lane a écrit :

CStringGetTextDatum

Can you give me more precisions ?

I'm creating a "user C function", with shared library and
CStringGetTextDatum is in "varlena.h" file which is not in the
"src/include" dir... How can I include it ?

Thanks.
Samuel.

Samuel ROZE wrote:

Le mercredi 21 octobre 2009 à 11:42 -0400, Tom Lane a écrit :

CStringGetTextDatum

Can you give me more precisions ?

I'm creating a "user C function", with shared library and
CStringGetTextDatum is in "varlena.h" file which is not in the
"src/include" dir... How can I include it ?

It's in utils/builtins.h, as a simple grep search should have told you.

cheers

andrew

I've done it but I had no results... strange.

I've a 8.3 version and this lines are NOT in the file:
00668 /* varlena.c */
00669 extern text *cstring_to_text(const char *s);
00670 extern text *cstring_to_text_with_len(const char *s, int len);
00671 extern char *text_to_cstring(const text *t);
00672 extern void text_to_cstring_buffer(const text *src, char *dst, size_t dst_len);
00673
00674 #define CStringGetTextDatum(s) PointerGetDatum(cstring_to_text(s))
00675 #define TextDatumGetCString(d) text_to_cstring((text *) DatumGetPointer(d))

Le mercredi 21 octobre 2009 à 12:28 -0400, Andrew Dunstan a écrit :

I'm now using C strings. I don't need to use CStringGetTextDatum, but it
still don't works. There's the code:

---------------------------------------------------------------
PG_FUNCTION_INFO_V1(parse_url_record);
Datum parse_url_record (PG_FUNCTION_ARGS)
{
// Vars about the params
//text *str2 = PG_GETARG_TEXT_P(0);
char str[] = "http://www.ovh.com/intenal.html&quot;;

// Some vars which will used to create the composite output type
TupleDesc tupdesc;
char **values;
HeapTuple tuple;
AttInMetadata *attinmeta;
bool nulls[2];
url *ret;

// Check NULLs values
if(PG_ARGISNULL(0) || PG_ARGISNULL(1)) {
PG_RETURN_NULL();
}

ret = parse_url_exec(str);

if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context that
cannot accept type record")));
}
attinmeta = TupleDescGetAttInMetadata(tupdesc);

// ...
values = (char **) palloc(2 * sizeof(char *));

// Add datas into the values Datum
values[0] = (char *) ret->scheme;
values[1] = (char *) ret->host;

// Convert values into a composite type
memset(nulls, 0, sizeof(nulls));

// build tuple from datum array
tuple = BuildTupleFromCStrings(attinmeta, values);

// Return the composite type
PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
}
---------------------------------------------------------------

Thanks a lot !
Samuel ROZE.

Le mercredi 21 octobre 2009 à 11:42 -0400, Tom Lane a écrit :

Samuel ROZE <samuel.roze@gmail.com> writes:

I've done it but I had no results... strange.
I've a 8.3 version and this lines are NOT in the file:

Oh, it was changed in 8.4 IIRC. If you are thinking of submitting
code to the project you should not be developing against a back
release anyway ...

regards, tom lane

Samuel ROZE wrote:

I've done it but I had no results... strange.

I've a 8.3 version and this lines are NOT in the file:

You neglected to tell us you were in 8.3 before, I think.

On 8.3 you might need to put a #define for it directly in your C file.

cheers

andrew

Le mercredi 21 octobre 2009 à 12:59 -0400, Andrew Dunstan a écrit :

On 8.3 you might need to put a #define for it directly in your C file.

I can't: cstring_to_text isn't defined.

I'll develop on 8.4.

Samuel ROZE wrote:

Le mercredi 21 octobre 2009 à 12:59 -0400, Andrew Dunstan a écrit :

On 8.3 you might need to put a #define for it directly in your C file.

I can't: cstring_to_text isn't defined.

I'll develop on 8.4.

or try:

#define CStringGetTextP(c) DatumGetTextP(DirectFunctionCall1(textin,
CStringGetDatum(c)))

cheers

andrew

It is solved. I'll propose my work the next weeks. :-)

Regards,
Samuel.

Le mercredi 21 octobre 2009 à 17:31 +0200, Samuel ROZE a écrit :