General function for SERIAL/IDENTITY/AUTOINCREMENT feature.

Handle INSERT event in timetravel().

1 files changed, 100 insertions, 0 deletions

diff --git a/contrib/spi/autoinc.c b/contrib/spi/autoinc.c
new file mode 100644
index 00000000000..2aceea60fa0
--- /dev/null
+++ b/contrib/spi/autoinc.c
@@ -0,0 +1,100 @@
+
+#include "executor/spi.h"		/* this is what you need to work with SPI */
+#include "commands/trigger.h"	/* -"- and triggers */
+
+HeapTuple		autoinc(void);
+
+extern int4	nextval(struct varlena * seqin);
+
+HeapTuple
+autoinc()
+{
+	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 */
+	char	  **args;			/* arguments */
+	char	   *relname;		/* triggered relation name */
+	Relation	rel;			/* triggered relation */
+	HeapTuple	rettuple = NULL;
+	TupleDesc	tupdesc;		/* tuple description */
+	bool		isnull;
+	int			i;
+
+	if (!CurrentTriggerData)
+		elog(WARN, "autoinc: triggers are not initialized");
+	if (TRIGGER_FIRED_FOR_STATEMENT(CurrentTriggerData->tg_event))
+		elog(WARN, "autoinc: can't process STATEMENT events");
+	if (TRIGGER_FIRED_AFTER(CurrentTriggerData->tg_event))
+		elog(WARN, "autoinc: must be fired before event");
+	
+	if (TRIGGER_FIRED_BY_INSERT(CurrentTriggerData->tg_event))
+		rettuple = CurrentTriggerData->tg_trigtuple;
+	else if (TRIGGER_FIRED_BY_UPDATE(CurrentTriggerData->tg_event))
+		rettuple = CurrentTriggerData->tg_newtuple;
+	else
+		elog(WARN, "autoinc: can't process DELETE events");
+	
+	rel = CurrentTriggerData->tg_relation;
+	relname = SPI_getrelname(rel);
+	
+	trigger = CurrentTriggerData->tg_trigger;
+
+	nargs = trigger->tgnargs;
+	if (nargs <= 0 || nargs % 2 != 0)
+		elog(WARN, "autoinc (%s): even number gt 0 of arguments was expected", relname);
+	
+	args = trigger->tgargs;
+	tupdesc = rel->rd_att;
+	
+	CurrentTriggerData = NULL;
+	
+	chattrs = (int *) palloc (nargs/2 * sizeof (int));
+	newvals = (Datum *) palloc (nargs/2 * sizeof (Datum));
+	
+	for (i = 0; i < nargs; )
+	{
+		struct varlena	   *seqname;
+		int					attnum = SPI_fnumber (tupdesc, args[i]);
+		int32				val;
+		
+		if ( attnum < 0 )
+			elog(WARN, "autoinc (%s): there is no attribute %s", relname, args[i]);
+		if (SPI_gettypeid (tupdesc, attnum) != INT4OID)
+			elog(WARN, "autoinc (%s): attribute %s must be of INT4 type", 
+					relname, args[i]);
+		
+		val = DatumGetInt32 (SPI_getbinval (rettuple, tupdesc, attnum, &isnull));
+		
+		if (!isnull && val != 0)
+		{
+			i += 2;
+			continue;
+		}
+		
+		i++;
+		chattrs[chnattrs] = attnum;
+		seqname = textin (args[i]);
+		newvals[chnattrs] = Int32GetDatum (nextval (seqname));
+		if ( DatumGetInt32 (newvals[chnattrs]) == 0 )
+			newvals[chnattrs] = Int32GetDatum (nextval (seqname));
+		pfree (seqname);
+		chnattrs++;
+		i++;
+	}
+	
+	if (chnattrs > 0)
+	{
+		rettuple = SPI_modifytuple (rel, rettuple, chnattrs, chattrs, newvals, NULL);
+		if ( rettuple == NULL )
+			elog (WARN, "autoinc (%s): %d returned by SPI_modifytuple",
+				relname, SPI_result);
+	}
+	
+	pfree (relname);
+	pfree (chattrs);
+	pfree (newvals);
+
+	return (rettuple);
+}