Function ExecFilterJunkInternal

src/backend/executor/execJunk.c:267–325

}

static TupleTableSlot *
ExecFilterJunkInternal(JunkFilter *junkfilter, TupleTableSlot *slot)
{
	TupleTableSlot *resultSlot;
	AttrNumber *cleanMap;
	TupleDesc	cleanTupType;
	int			cleanLength;
	int			i;
	Datum	   *values;
	bool	   *isnull;
	Datum	   *old_values;
	bool	   *old_isnull;

	/*
	 * Extract all the values of the old tuple.
	 */
	slot_getallattrs(slot);
	old_values = slot->tts_values;
	old_isnull = slot->tts_isnull;

	/*
	 * get info from the junk filter
	 */
	cleanTupType = junkfilter->jf_cleanTupType;
	cleanLength = cleanTupType->natts;
	cleanMap = junkfilter->jf_cleanMap;
	resultSlot = junkfilter->jf_resultSlot;

	/*
	 * Prepare to build a virtual result tuple.
	 */
	ExecClearTuple(resultSlot);
	values = resultSlot->tts_values;
	isnull = resultSlot->tts_isnull;

	/*
	 * Transpose data into proper fields of the new tuple.
	 */
	for (i = 0; i < cleanLength; i++)
	{
		int			j = cleanMap[i];

		if (j == 0)
		{
			values[i] = (Datum) 0;
			isnull[i] = true;
		}
		else
		{
			values[i] = old_values[j - 1];
			isnull[i] = old_isnull[j - 1];
		}
	}

	/*
	 * And return the virtual tuple.
	 */
	return ExecStoreVirtualTuple(resultSlot);