Datum /* have to return HeapTuple to Executor */
timetravel(PG_FUNCTION_ARGS)
{
TriggerData *trigdata = (TriggerData *) fcinfo->context;
Trigger *trigger; /* to get trigger name */
int argc;
char **args; /* arguments */
int attnum[MaxAttrNum]; /* fnumbers of start/stop columns */
Datum oldtimeon,
oldtimeoff;
Datum newtimeon,
newtimeoff,
newuser,
nulltext;
Datum *cvals; /* column values */
char *cnulls; /* column nulls */
char *relname; /* triggered relation name */
Relation rel; /* triggered relation */
HeapTuple trigtuple;
HeapTuple newtuple = NULL;
HeapTuple rettuple;
TupleDesc tupdesc; /* tuple description */
int natts; /* # of attributes */
EPlan *plan; /* prepared plan */
char ident[2 * NAMEDATALEN];
bool isnull; /* to know is some column NULL or not */
bool isinsert = false;
int ret;
int i;
/*
* Some checks first...
*/
/* Called by trigger manager ? */
if (!CALLED_AS_TRIGGER(fcinfo))
elog(ERROR, "timetravel: not fired by trigger manager");
/* Should be called for ROW trigger */
if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
elog(ERROR, "timetravel: must be fired for row");
/* Should be called BEFORE */
if (!TRIGGER_FIRED_BEFORE(trigdata->tg_event))
elog(ERROR, "timetravel: must be fired before event");
/* INSERT ? */
if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
isinsert = true;
if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
newtuple = trigdata->tg_newtuple;
trigtuple = trigdata->tg_trigtuple;
rel = trigdata->tg_relation;
relname = SPI_getrelname(rel);
/* check if TT is OFF for this relation */
if (0 == findTTStatus(relname))
{
/* OFF - nothing to do */
pfree(relname);
return PointerGetDatum((newtuple != NULL) ? newtuple : trigtuple);
}
trigger = trigdata->tg_trigger;
argc = trigger->tgnargs;
if (argc != MinAttrNum && argc != MaxAttrNum)
elog(ERROR, "timetravel (%s): invalid (!= %d or %d) number of arguments %d",
relname, MinAttrNum, MaxAttrNum, trigger->tgnargs);
args = trigger->tgargs;
tupdesc = rel->rd_att;
natts = tupdesc->natts;
for (i = 0; i < MinAttrNum; i++)
{
attnum[i] = SPI_fnumber(tupdesc, args[i]);
if (attnum[i] <= 0)
elog(ERROR, "timetravel (%s): there is no attribute %s", relname, args[i]);
if (SPI_gettypeid(tupdesc, attnum[i]) != ABSTIMEOID)
elog(ERROR, "timetravel (%s): attribute %s must be of abstime type",
relname, args[i]);
}
for (; i < argc; i++)
{
attnum[i] = SPI_fnumber(tupdesc, args[i]);
if (attnum[i] <= 0)
elog(ERROR, "timetravel (%s): there is no attribute %s", relname, args[i]);
if (SPI_gettypeid(tupdesc, attnum[i]) != TEXTOID)
elog(ERROR, "timetravel (%s): attribute %s must be of text type",
relname, args[i]);
}
/* create fields containing name */
newuser = CStringGetTextDatum(GetUserNameFromId(GetUserId(), false));
nulltext = (Datum) NULL;
if (isinsert)
{ /* INSERT */
int chnattrs = 0;
int chattrs[MaxAttrNum];
Datum newvals[MaxAttrNum];
bool newnulls[MaxAttrNum];
oldtimeon = SPI_getbinval(trigtuple, tupdesc, attnum[a_time_on], &isnull);
if (isnull)
{
newvals[chnattrs] = GetCurrentAbsoluteTime();
newnulls[chnattrs] = false;
chattrs[chnattrs] = attnum[a_time_on];
chnattrs++;
}
oldtimeoff = SPI_getbinval(trigtuple, tupdesc, attnum[a_time_off], &isnull);
if (isnull)
{
if ((chnattrs == 0 && DatumGetInt32(oldtimeon) >= NOEND_ABSTIME) ||
(chnattrs > 0 && DatumGetInt32(newvals[a_time_on]) >= NOEND_ABSTIME))
elog(ERROR, "timetravel (%s): %s is infinity", relname, args[a_time_on]);
newvals[chnattrs] = NOEND_ABSTIME;
newnulls[chnattrs] = false;
chattrs[chnattrs] = attnum[a_time_off];
chnattrs++;
}
else
{
if ((chnattrs == 0 && DatumGetInt32(oldtimeon) > DatumGetInt32(oldtimeoff)) ||
(chnattrs > 0 && DatumGetInt32(newvals[a_time_on]) > DatumGetInt32(oldtimeoff)))
elog(ERROR, "timetravel (%s): %s gt %s", relname, args[a_time_on], args[a_time_off]);
}
pfree(relname);
if (chnattrs <= 0)
return PointerGetDatum(trigtuple);
if (argc == MaxAttrNum)
{
/* clear update_user value */
newvals[chnattrs] = nulltext;
newnulls[chnattrs] = true;
chattrs[chnattrs] = attnum[a_upd_user];
chnattrs++;
/* clear delete_user value */
newvals[chnattrs] = nulltext;
newnulls[chnattrs] = true;
chattrs[chnattrs] = attnum[a_del_user];
chnattrs++;
/* set insert_user value */
newvals[chnattrs] = newuser;
newnulls[chnattrs] = false;
chattrs[chnattrs] = attnum[a_ins_user];
chnattrs++;
}
rettuple = heap_modify_tuple_by_cols(trigtuple, tupdesc,
chnattrs, chattrs,
newvals, newnulls);
return PointerGetDatum(rettuple);
/* end of INSERT */
}
/* UPDATE/DELETE: */
oldtimeon = SPI_getbinval(trigtuple, tupdesc, attnum[a_time_on], &isnull);
if (isnull)
elog(ERROR, "timetravel (%s): %s must be NOT NULL", relname, args[a_time_on]);
oldtimeoff = SPI_getbinval(trigtuple, tupdesc, attnum[a_time_off], &isnull);
if (isnull)
elog(ERROR, "timetravel (%s): %s must be NOT NULL", relname, args[a_time_off]);
/*
* If DELETE/UPDATE of tuple with stop_date neq INFINITY then say upper
* Executor to skip operation for this tuple
*/
if (newtuple != NULL)
{ /* UPDATE */
newtimeon = SPI_getbinval(newtuple, tupdesc, attnum[a_time_on], &isnull);
if (isnull)
elog(ERROR, "timetravel (%s): %s must be NOT NULL", relname, args[a_time_on]);
newtimeoff = SPI_getbinval(newtuple, tupdesc, attnum[a_time_off], &isnull);
if (isnull)
elog(ERROR, "timetravel (%s): %s must be NOT NULL", relname, args[a_time_off]);
if (oldtimeon != newtimeon || oldtimeoff != newtimeoff)
elog(ERROR, "timetravel (%s): you cannot change %s and/or %s columns (use set_timetravel)",
relname, args[a_time_on], args[a_time_off]);
}
if (oldtimeoff != NOEND_ABSTIME)
{ /* current record is a deleted/updated record */
pfree(relname);
return PointerGetDatum(NULL);
}
newtimeoff = GetCurrentAbsoluteTime();
/* Connect to SPI manager */
if ((ret = SPI_connect()) < 0)
elog(ERROR, "timetravel (%s): SPI_connect returned %d", relname, ret);
/* Fetch tuple values and nulls */
cvals = (Datum *) palloc(natts * sizeof(Datum));
cnulls = (char *) palloc(natts * sizeof(char));
for (i = 0; i < natts; i++)
{
cvals[i] = SPI_getbinval(trigtuple, tupdesc, i + 1, &isnull);
cnulls[i] = (isnull) ? 'n' : ' ';
}
/* change date column(s) */
cvals[attnum[a_time_off] - 1] = newtimeoff; /* stop_date eq current date */
cnulls[attnum[a_time_off] - 1] = ' ';
if (!newtuple)
{ /* DELETE */
if (argc == MaxAttrNum)
{
cvals[attnum[a_del_user] - 1] = newuser; /* set delete user */
cnulls[attnum[a_del_user] - 1] = ' ';
}
}
/*
* Construct ident string as TriggerName $ TriggeredRelationId and try to
* find prepared execution plan.
*/
snprintf(ident, sizeof(ident), "%s$%u", trigger->tgname, rel->rd_id);
plan = find_plan(ident, &Plans, &nPlans);
/* if there is no plan ... */
if (plan->splan == NULL)
{
SPIPlanPtr pplan;
Oid *ctypes;
char sql[8192];
char separ = ' ';
/* allocate ctypes for preparation */
ctypes = (Oid *) palloc(natts * sizeof(Oid));
/*
* Construct query: INSERT INTO _relation_ VALUES ($1, ...)
*/
snprintf(sql, sizeof(sql), "INSERT INTO %s VALUES (", relname);
for (i = 1; i <= natts; i++)
{
ctypes[i - 1] = SPI_gettypeid(tupdesc, i);
if (!(tupdesc->attrs[i - 1]->attisdropped)) /* skip dropped columns */
{
snprintf(sql + strlen(sql), sizeof(sql) - strlen(sql), "%c$%d", separ, i);
separ = ',';
}
}
snprintf(sql + strlen(sql), sizeof(sql) - strlen(sql), ")");
elog(DEBUG4, "timetravel (%s) update: sql: %s", relname, sql);
/* Prepare plan for query */
pplan = SPI_prepare(sql, natts, ctypes);
if (pplan == NULL)
elog(ERROR, "timetravel (%s): SPI_prepare returned %d", relname, SPI_result);
/*
* Remember that SPI_prepare places plan in current memory context -
* so, we have to save plan in Top memory context for later use.
*/
if (SPI_keepplan(pplan))
elog(ERROR, "timetravel (%s): SPI_keepplan failed", relname);
plan->splan = pplan;
}
/*
* Ok, execute prepared plan.
*/
ret = SPI_execp(plan->splan, cvals, cnulls, 0);
if (ret < 0)
elog(ERROR, "timetravel (%s): SPI_execp returned %d", relname, ret);
/* Tuple to return to upper Executor ... */
if (newtuple)
{ /* UPDATE */
int chnattrs = 0;
int chattrs[MaxAttrNum];
Datum newvals[MaxAttrNum];
char newnulls[MaxAttrNum];
newvals[chnattrs] = newtimeoff;
newnulls[chnattrs] = ' ';
chattrs[chnattrs] = attnum[a_time_on];
chnattrs++;
newvals[chnattrs] = NOEND_ABSTIME;
newnulls[chnattrs] = ' ';
chattrs[chnattrs] = attnum[a_time_off];
chnattrs++;
if (argc == MaxAttrNum)
{
/* set update_user value */
newvals[chnattrs] = newuser;
newnulls[chnattrs] = ' ';
chattrs[chnattrs] = attnum[a_upd_user];
chnattrs++;
/* clear delete_user value */
newvals[chnattrs] = nulltext;
newnulls[chnattrs] = 'n';
chattrs[chnattrs] = attnum[a_del_user];
chnattrs++;
/* set insert_user value */
newvals[chnattrs] = nulltext;
newnulls[chnattrs] = 'n';
chattrs[chnattrs] = attnum[a_ins_user];
chnattrs++;
}
/*
* Use SPI_modifytuple() here because we are inside SPI environment
* but rettuple must be allocated in caller's context.
*/
rettuple = SPI_modifytuple(rel, newtuple, chnattrs, chattrs, newvals, newnulls);
}
else
/* DELETE case */
rettuple = trigtuple;
SPI_finish(); /* don't forget say Bye to SPI mgr */
pfree(relname);
return PointerGetDatum(rettuple);
}
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);
}
