/*

* contrib/spi/autoinc.c

*/

#include "postgres.h"

#include "access/htup_details.h"

#include "catalog/pg_type.h"

#include "commands/sequence.h"

#include "commands/trigger.h"

#include "executor/spi.h"

#include "utils/builtins.h"

#include "utils/rel.h"

PG_MODULE_MAGIC;

PG_FUNCTION_INFO_V1(autoinc);

Datum

autoinc(PG_FUNCTION_ARGS)

{

TriggerData *trigdata = (TriggerData *) fcinfo->context;

Trigger *trigger; /* to get trigger name */

int nargs; /* # of arguments */

int *chattrs; /* attnums of attributes to change */

int chnattrs = 0; /* # of above */

Datum *newvals; /* vals of above */

bool *newnulls; /* null flags for above */

char **args; /* arguments */

char *relname; /* triggered relation name */

Relation rel; /* triggered relation */

HeapTuple rettuple = NULL;

TupleDesc tupdesc; /* tuple description */

bool isnull;

int i;

if (!CALLED_AS_TRIGGER(fcinfo))

/* internal error */

elog(ERROR, "not fired by trigger manager");

if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))

/* internal error */

elog(ERROR, "must be fired for row");

if (!TRIGGER_FIRED_BEFORE(trigdata->tg_event))

/* internal error */

elog(ERROR, "must be fired before event");

if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))

rettuple = trigdata->tg_trigtuple;

else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))

rettuple = trigdata->tg_newtuple;

else

/* internal error */

elog(ERROR, "cannot process DELETE events");

rel = trigdata->tg_relation;

relname = SPI_getrelname(rel);

trigger = trigdata->tg_trigger;

nargs = trigger->tgnargs;

if (nargs <= 0 || nargs % 2 != 0)

/* internal error */

elog(ERROR, "autoinc (%s): even number gt 0 of arguments was expected", relname);

args = trigger->tgargs;

tupdesc = rel->rd_att;

chattrs = (int *) palloc(nargs / 2 * sizeof(int));

newvals = (Datum *) palloc(nargs / 2 * sizeof(Datum));

newnulls = (bool *) palloc(nargs / 2 * sizeof(bool));

for (i = 0; i < nargs;)

{

int attnum = SPI_fnumber(tupdesc, args[i]);

int32 val;

Datum seqname;

if (attnum <= 0)

ereport(ERROR,

(errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),

errmsg("\"%s\" has no attribute \"%s\"",

relname, args[i])));

if (SPI_gettypeid(tupdesc, attnum) != INT4OID)

ereport(ERROR,

(errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),

errmsg("attribute \"%s\" of \"%s\" must be type INT4",

args[i], relname)));

val = DatumGetInt32(SPI_getbinval(rettuple, tupdesc, attnum, &isnull));

if (!isnull && val != 0)

{

i += 2;

continue;

}

i++;

chattrs[chnattrs] = attnum;

seqname = CStringGetTextDatum(args[i]);

newvals[chnattrs] = DirectFunctionCall1(nextval, seqname);

/* nextval now returns int64; coerce down to int32 */

newvals[chnattrs] = Int32GetDatum((int32) DatumGetInt64(newvals[chnattrs]));

if (DatumGetInt32(newvals[chnattrs]) == 0)

{

newvals[chnattrs] = DirectFunctionCall1(nextval, seqname);

newvals[chnattrs] = Int32GetDatum((int32) DatumGetInt64(newvals[chnattrs]));

}

newnulls[chnattrs] = false;

pfree(DatumGetTextPP(seqname));

chnattrs++;

i++;

}

if (chnattrs > 0)

{

rettuple = heap_modify_tuple_by_cols(rettuple, tupdesc,

chnattrs, chattrs,

newvals, newnulls);

}

pfree(relname);

pfree(chattrs);

pfree(newvals);

pfree(newnulls);

return PointerGetDatum(rettuple);

}