Method process

src/dsql/BoolNodes.cpp:1698–1808

Replace NOT with an appropriately inverted condition, if possible. Get rid of redundant nested NOT predicates.

// Replace NOT with an appropriately inverted condition, if possible.
// Get rid of redundant nested NOT predicates.
BoolExprNode* NotBoolNode::process(DsqlCompilerScratch* dsqlScratch, bool invert)
{
	MemoryPool& pool = dsqlScratch->getPool();
	NotBoolNode* notArg = nodeAs<NotBoolNode>(arg);

	if (notArg)
	{
		// Recurse until different node is found (every even call means no inversion required).
		return notArg->process(dsqlScratch, !invert);
	}

	if (!invert)
		return arg->dsqlPass(dsqlScratch);

	ComparativeBoolNode* cmpArg = nodeAs<ComparativeBoolNode>(arg);
	BinaryBoolNode* binArg = nodeAs<BinaryBoolNode>(arg);

	// Do not handle special case: <value> NOT IN <list>

	if (cmpArg && (!cmpArg->dsqlSpecialArg || !nodeIs<ValueListNode>(cmpArg->dsqlSpecialArg)))
	{
		// Invert the given boolean.
		switch (cmpArg->blrOp)
		{
			case blr_eql:
			case blr_neq:
			case blr_lss:
			case blr_gtr:
			case blr_leq:
			case blr_geq:
			{
				UCHAR newBlrOp;

				switch (cmpArg->blrOp)
				{
					case blr_eql:
						newBlrOp = blr_neq;
						break;
					case blr_neq:
						newBlrOp = blr_eql;
						break;
					case blr_lss:
						newBlrOp = blr_geq;
						break;
					case blr_gtr:
						newBlrOp = blr_leq;
						break;
					case blr_leq:
						newBlrOp = blr_gtr;
						break;
					case blr_geq:
						newBlrOp = blr_lss;
						break;
					default:
						fb_assert(false);
						return NULL;
				}