Function test_predtest

src/test/modules/test_predtest/test_predtest.c:32–231

PG_FUNCTION_INFO_V1(test_predtest);

Datum
test_predtest(PG_FUNCTION_ARGS)
{
	text	   *txt = PG_GETARG_TEXT_PP(0);
	char	   *query_string = text_to_cstring(txt);
	SPIPlanPtr	spiplan;
	int			spirc;
	TupleDesc	tupdesc;
	bool		s_i_holds,
				w_i_holds,
				s_r_holds,
				w_r_holds;
	CachedPlan *cplan;
	PlannedStmt *stmt;
	Plan	   *plan;
	Expr	   *clause1;
	Expr	   *clause2;
	bool		strong_implied_by,
				weak_implied_by,
				strong_refuted_by,
				weak_refuted_by;
	Datum		values[8];
	bool		nulls[8];
	int			i;

	/* We use SPI to parse, plan, and execute the test query */
	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "SPI_connect failed");

	/*
	 * First, plan and execute the query, and inspect the results.  To the
	 * extent that the query fully exercises the two expressions, this
	 * provides an experimental indication of whether implication or
	 * refutation holds.
	 */
	spiplan = SPI_prepare(query_string, 0, NULL);
	if (spiplan == NULL)
		elog(ERROR, "SPI_prepare failed for \"%s\"", query_string);

	spirc = SPI_execute_plan(spiplan, NULL, NULL, true, 0);
	if (spirc != SPI_OK_SELECT)
		elog(ERROR, "failed to execute \"%s\"", query_string);
	tupdesc = SPI_tuptable->tupdesc;
	if (tupdesc->natts != 2 ||
		TupleDescAttr(tupdesc, 0)->atttypid != BOOLOID ||
		TupleDescAttr(tupdesc, 1)->atttypid != BOOLOID)
		elog(ERROR, "query must yield two boolean columns");

	s_i_holds = w_i_holds = s_r_holds = w_r_holds = true;
	for (i = 0; i < SPI_processed; i++)
	{
		HeapTuple	tup = SPI_tuptable->vals[i];
		Datum		dat;
		bool		isnull;
		char		c1,
					c2;

		/* Extract column values in a 3-way representation */