void IntersectQP::applyConversionRules(unsigned int maxAlternatives, OptimizationContext &opt, QueryPlans &alternatives)
{
XPath2MemoryManager *mm = opt.getMemoryManager();
removeSupersets(opt);
// Return if we only have one argument
if(args_.size() == 1) {
alternatives.push_back(args_[0]);
return;
}
// TBD remove the need for QueryExecutionContext here - jpcs
QueryExecutionContext qec(GET_CONFIGURATION(opt.getContext())->getQueryContext(),
/*debugging*/false);
qec.setContainerBase(opt.getContainerBase());
qec.setDynamicContext(opt.getContext());
// Sort the arguments based on how many keys we think they'll return
sort(args_.begin(), args_.end(), keys_compare_less(opt.getOperationContext(), qec));
alternatives.push_back(this);
for(Vector::const_iterator it = args_.begin(); it != args_.end(); ++it) {
for(Vector::const_iterator it2 = it + 1; it2 != args_.end(); ++it2) {
QueryPlans alts;
applyConversionRules2Args(maxAlternatives, *it, *it2, opt, alts);
for(QueryPlans::iterator it3 = alts.begin(); it3 != alts.end(); ++it3) {
IntersectQP *newIntersect = new (mm) IntersectQP(flags_, mm);
newIntersect->setLocationInfo(this);
Vector::const_iterator it4;
// Copy args before "it"
for(it4 = args_.begin(); it4 != it; ++it4) {
newIntersect->addArg((*it4)->copy(mm));
}
// Add new alternative
newIntersect->addArg(*it3);
// Copy args from after "it" to before "it2"
for(++it4; it4 != it2; ++it4) {
newIntersect->addArg((*it4)->copy(mm));
}
// Copy args from after "it2"
for(++it4; it4 != args_.end(); ++it4) {
newIntersect->addArg((*it4)->copy(mm));
}
newIntersect->applyConversionRules(maxAlternatives, opt, alternatives);
}
}
}
}
