C++ ParseTree::data方法代码示例

bool operator==(const ParseTree& t1,
				const ParseTree& t2)
{
	if (t1.data() != NULL && t2.data() != NULL) {
		if (*t1.data() != t2.data())
			return false;
	}
	else if (t1.data() != NULL || t2.data() != NULL)
		return false;

	if (t1.left() != NULL && t2.left() != NULL) {
		if (*t1.left() != *t2.left())
			return false;
	}
	else if (t1.left() != NULL || t2.left() != NULL)
		return false;
	
	if (t1.right() != NULL && t2.right() != NULL) {
		if (*t1.right() != *t2.right())
			return false;
	}
	else if (t1.right() != NULL || t2.right() != NULL)
		return false;
	
	return true;
}

/**
 * This is invoked when a NOT function is got. It's usually the case NOT<IN optimizer>
 * This function will simple turn the semi join to anti join
 *
 */
void InSub::handleNot()
{
	ParseTree *pt = fGwip.ptWorkStack.top();
	ExistsFilter *subFilter = dynamic_cast<ExistsFilter*>(pt->data());
	idbassert(subFilter);
	subFilter->notExists(true);
	SCSEP csep = subFilter->sub();
	const ParseTree* ptsub = csep->filters();
	if (ptsub)
		ptsub->walk(makeAntiJoin);
	ptsub = csep->having();
	if (ptsub)
		ptsub->walk(makeAntiJoin);
}

ParseTree* ObjectReader::createParseTree(messageqcpp::ByteStream& b)
{
	CLASSID id = ZERO;
	ParseTree* ret;
	
	b >> (id_t&) id;
	if (id == NULL_CLASS)
		return NULL;
	if (id != PARSETREE)
		throw UnserializeException("Not a ParseTree");
	
	ret = new ParseTree();
	ret->left(createParseTree(b));
	ret->right(createParseTree(b));
	ret->data(createTreeNode(b));
	return ret;
}	

/**
 * Handle MySQL's plugin functions
 * This is mostly for handling the null related functions that MySQL adds to the execution plan
 */
void InSub::handleFunc(gp_walk_info* gwip, Item_func* func)
{
    if (func->functype() == Item_func::TRIG_COND_FUNC || func->functype() == Item_func::COND_OR_FUNC)
    {
        // purpose: remove the isnull() function from the parsetree in ptWorkStack.
        // IDB handles the null semantics in the join operation
        // trigcond(or_cond) is the only form we recognize for now
        if (func->argument_count() > 2)
        {
            fGwip.fatalParseError = true;
            fGwip.parseErrorText = "Unsupported item in IN subquery";
            return;
        }

        Item_cond* cond;

        if (func->functype() == Item_func::TRIG_COND_FUNC)
        {
            Item* item;

            if (func->arguments()[0]->type() == Item::REF_ITEM)
                item = (Item_ref*)(func->arguments()[0])->real_item();
            else
                item = func->arguments()[0];

            cond = (Item_cond*)(item);
        }
        else
        {
            cond = (Item_cond*)(func);
        }

        if (cond->functype() == Item_func::COND_OR_FUNC)
        {
            // (cache=item) case. do nothing. ignore trigcond()?
            if (cond->argument_list()->elements == 1)
                return;

            // (cache=item or isnull(item)) case. remove "or isnull()"
            if (cond->argument_list()->elements == 2)
            {
                // don't know how to deal with this. don't think it's a fatal error either.
                if (gwip->ptWorkStack.empty())
                    return;

                ParseTree* pt = gwip->ptWorkStack.top();

                if (!pt->left() || !pt->right())
                    return;

                SimpleFilter* sf = dynamic_cast<SimpleFilter*>(pt->left()->data());

                //assert (sf && sf->op()->op() == execplan::OP_ISNULL);
                if (!sf || sf->op()->op() != execplan::OP_ISNULL)
                    return;

                delete sf;
                sf = dynamic_cast<SimpleFilter*>(pt->right()->data());

                //idbassert(sf && sf->op()->op() == execplan::OP_EQ);
                if (!sf || sf->op()->op() != execplan::OP_EQ)
                    return;

                // set NULLMATCH for both operand. It's really a setting for the join.
                // should only set NULLMATCH when the subtype is NOT_IN. for some IN subquery
                // with aggregation column, MySQL inefficiently convert to:
                // (cache=item or item is null) and item is not null, which is equivalent to
                // cache = item. Do not set NULLMATCH for this case.
                // Because we don't know IN or NOTIN yet, set candidate bit and switch to NULLMATCH
                // later in handleNot function.
                if (sf->lhs()->joinInfo() & JOIN_CORRELATED)
                    sf->lhs()->joinInfo(sf->lhs()->joinInfo() | JOIN_NULLMATCH_CANDIDATE);

                if (sf->rhs()->joinInfo() & JOIN_CORRELATED)
                    sf->rhs()->joinInfo(sf->rhs()->joinInfo() | JOIN_NULLMATCH_CANDIDATE);

                pt = pt->right();
                gwip->ptWorkStack.pop();
                gwip->ptWorkStack.push(pt);
            }
        }
        else if (cond->functype() == Item_func::EQ_FUNC)
        {
            // not in (select const ...)
            if (gwip->ptWorkStack.empty())
                return;

            ParseTree* pt = gwip->ptWorkStack.top();
            SimpleFilter* sf = dynamic_cast<SimpleFilter*>(pt->data());

            if (!sf || sf->op()->op() != execplan::OP_EQ)
                return;

            if (sf->lhs()->joinInfo() & JOIN_CORRELATED)
                sf->lhs()->joinInfo(sf->lhs()->joinInfo() | JOIN_NULLMATCH_CANDIDATE);

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