- log(DEBUG, "DNS lookup failed (%s), dying horribly", errormessage.c_str());
- }
-
- virtual ~SQLresolver()
- {
- }
-};
-
-/** QueryQueue, a queue of queries waiting to be executed.
- * This maintains two queues internally, one for 'priority'
- * queries and one for less important ones. Each queue has
- * new queries appended to it and ones to execute are popped
- * off the front. This keeps them flowing round nicely and no
- * query should ever get 'stuck' for too long. If there are
- * queries in the priority queue they will be executed first,
- * 'unimportant' queries will only be executed when the
- * priority queue is empty.
- *
- * We store lists of SQLrequest's here, by value as we want to avoid storing
- * any data allocated inside the client module (in case that module is unloaded
- * while the query is in progress).
- *
- * Because we want to work on the current SQLrequest in-situ, we need a way
- * of accessing the request we are currently processing, QueryQueue::front(),
- * but that call needs to always return the same request until that request
- * is removed from the queue, this is what the 'which' variable is. New queries are
- * always added to the back of one of the two queues, but if when front()
- * is first called then the priority queue is empty then front() will return
- * a query from the normal queue, but if a query is then added to the priority
- * queue then front() must continue to return the front of the *normal* queue
- * until pop() is called.
- */
-
-class QueryQueue : public classbase
-{
-private:
- typedef std::deque<SQLrequest> ReqDeque;
-
- ReqDeque priority; /* The priority queue */
- ReqDeque normal; /* The 'normal' queue */
- enum { PRI, NOR, NON } which; /* Which queue the currently active element is at the front of */
-
-public:
- QueryQueue()
- : which(NON)
- {
- }
-
- void push(const SQLrequest &q)
- {
- //log(DEBUG, "QueryQueue::push(): Adding %s query to queue: %s", ((q.pri) ? "priority" : "non-priority"), q.query.q.c_str());
-
- if(q.pri)
- priority.push_back(q);
- else
- normal.push_back(q);
- }
-
- void pop()
- {
- if((which == PRI) && priority.size())
- {
- priority.pop_front();
- }
- else if((which == NOR) && normal.size())
- {
- normal.pop_front();
- }
-
- /* Reset this */
- which = NON;
-
- /* Silently do nothing if there was no element to pop() */
- }
-
- SQLrequest& front()
- {
- switch(which)
- {
- case PRI:
- return priority.front();
- case NOR:
- return normal.front();
- default:
- if(priority.size())
- {
- which = PRI;
- return priority.front();
- }
-
- if(normal.size())
- {
- which = NOR;
- return normal.front();
- }
-
- /* This will probably result in a segfault,
- * but the caller should have checked totalsize()
- * first so..meh - moron :p
- */
-
- return priority.front();
- }
- }
-
- std::pair<int, int> size()
- {
- return std::make_pair(priority.size(), normal.size());
- }
-
- int totalsize()
- {
- return priority.size() + normal.size();
- }
-
- void PurgeModule(Module* mod)
- {
- DoPurgeModule(mod, priority);
- DoPurgeModule(mod, normal);
- }
-
-private:
- void DoPurgeModule(Module* mod, ReqDeque& q)
- {
- for(ReqDeque::iterator iter = q.begin(); iter != q.end(); iter++)
- {
- if(iter->GetSource() == mod)
- {
- if(iter->id == front().id)
- {
- /* It's the currently active query.. :x */
- iter->SetSource(NULL);
- }
- else
- {
- /* It hasn't been executed yet..just remove it */
- iter = q.erase(iter);
- }
- }
- }