/** * @file llevents.cpp * @author Nat Goodspeed * @date 2008-09-12 * @brief Implementation for llevents. * * $LicenseInfo:firstyear=2008&license=viewergpl$ * Copyright (c) 2008, Linden Research, Inc. * $/LicenseInfo$ */ // Precompiled header #include "linden_common.h" #if LL_WINDOWS #pragma warning (disable : 4675) // "resolved by ADL" -- just as I want! #endif // associated header #include "llevents.h" // STL headers #include <set> #include <sstream> #include <algorithm> // std headers #include <typeinfo> #include <cassert> #include <cmath> #include <cctype> // external library headers #include <boost/range/iterator_range.hpp> #if LL_WINDOWS #pragma warning (push) #pragma warning (disable : 4701) // compiler thinks might use uninitialized var, but no #endif #include <boost/lexical_cast.hpp> #if LL_WINDOWS #pragma warning (pop) #endif // other Linden headers #include "stringize.h" #include "llerror.h" #include "llsdutil.h" #if LL_MSVC #pragma warning (disable : 4702) #endif /***************************************************************************** * queue_names: specify LLEventPump names that should be instantiated as * LLEventQueue *****************************************************************************/ /** * At present, we recognize particular requested LLEventPump names as needing * LLEventQueues. Later on we'll migrate this information to an external * configuration file. */ const char* queue_names[] = { "placeholder - replace with first real name string" }; /***************************************************************************** * If there's a "mainloop" pump, listen on that to flush all LLEventQueues *****************************************************************************/ struct RegisterFlush : public LLEventTrackable { RegisterFlush(): pumps(LLEventPumps::instance()) { pumps.obtain("mainloop").listen("flushLLEventQueues", boost::bind(&RegisterFlush::flush, this, _1)); } bool flush(const LLSD&) { pumps.flush(); return false; } ~RegisterFlush() { // LLEventTrackable handles stopListening for us. } LLEventPumps& pumps; }; static RegisterFlush registerFlush; /***************************************************************************** * LLEventPumps *****************************************************************************/ LLEventPumps::LLEventPumps(): // Until we migrate this information to an external config file, // initialize mQueueNames from the static queue_names array. mQueueNames(boost::begin(queue_names), boost::end(queue_names)) { } LLEventPump& LLEventPumps::obtain(const std::string& name) { PumpMap::iterator found = mPumpMap.find(name); if (found != mPumpMap.end()) { // Here we already have an LLEventPump instance with the requested // name. return *found->second; } // Here we must instantiate an LLEventPump subclass. LLEventPump* newInstance; // Should this name be an LLEventQueue? PumpNames::const_iterator nfound = mQueueNames.find(name); if (nfound != mQueueNames.end()) newInstance = new LLEventQueue(name); else newInstance = new LLEventStream(name); // LLEventPump's constructor implicitly registers each new instance in // mPumpMap. But remember that we instantiated it (in mOurPumps) so we'll // delete it later. mOurPumps.insert(newInstance); return *newInstance; } void LLEventPumps::flush() { // Flush every known LLEventPump instance. Leave it up to each instance to // decide what to do with the flush() call. for (PumpMap::iterator pmi = mPumpMap.begin(), pmend = mPumpMap.end(); pmi != pmend; ++pmi) { pmi->second->flush(); } } std::string LLEventPumps::registerNew(const LLEventPump& pump, const std::string& name, bool tweak) { std::pair<PumpMap::iterator, bool> inserted = mPumpMap.insert(PumpMap::value_type(name, const_cast<LLEventPump*>(&pump))); // If the insert worked, then the name is unique; return that. if (inserted.second) return name; // Here the new entry was NOT inserted, and therefore name isn't unique. // Unless we're permitted to tweak it, that's Bad. if (! tweak) { throw LLEventPump::DupPumpName(std::string("Duplicate LLEventPump name '") + name + "'"); } // The passed name isn't unique, but we're permitted to tweak it. Find the // first decimal-integer suffix not already taken. The insert() attempt // above will have set inserted.first to the iterator of the existing // entry by that name. Starting there, walk forward until we reach an // entry that doesn't start with 'name'. For each entry consisting of name // + integer suffix, capture the integer suffix in a set. Use a set // because we're going to encounter string suffixes in the order: name1, // name10, name11, name2, ... Walking those possibilities in that order // isn't convenient to detect the first available "hole." std::set<int> suffixes; PumpMap::iterator pmi(inserted.first), pmend(mPumpMap.end()); // We already know inserted.first references the existing entry with // 'name' as the key; skip that one and start with the next. while (++pmi != pmend) { if (pmi->first.substr(0, name.length()) != name) { // Found the first entry beyond the entries starting with 'name': // stop looping. break; } // Here we're looking at an entry that starts with 'name'. Is the rest // of it an integer? // Dubious (?) assumption: in the local character set, decimal digits // are in increasing order such that '9' is the last of them. This // test deals with 'name' values such as 'a', where there might be a // very large number of entries starting with 'a' whose suffixes // aren't integers. A secondary assumption is that digit characters // precede most common name characters (true in ASCII, false in // EBCDIC). The test below is correct either way, but it's worth more // if the assumption holds. if (pmi->first[name.length()] > '9') break; // It should be cheaper to detect that we're not looking at a digit // character -- and therefore the suffix can't possibly be an integer // -- than to attempt the lexical_cast and catch the exception. if (! std::isdigit(pmi->first[name.length()])) continue; // Okay, the first character of the suffix is a digit, it's worth at // least attempting to convert to int. try { suffixes.insert(boost::lexical_cast<int>(pmi->first.substr(name.length()))); } catch (const boost::bad_lexical_cast&) { // If the rest of pmi->first isn't an int, just ignore it. } } // Here we've accumulated in 'suffixes' all existing int suffixes of the // entries starting with 'name'. Find the first unused one. int suffix = 1; for ( ; suffixes.find(suffix) != suffixes.end(); ++suffix) ; // Here 'suffix' is not in 'suffixes'. Construct a new name based on that // suffix, insert it and return it. std::ostringstream out; out << name << suffix; return registerNew(pump, out.str(), tweak); } void LLEventPumps::unregister(const LLEventPump& pump) { // Remove this instance from mPumpMap PumpMap::iterator found = mPumpMap.find(pump.getName()); if (found != mPumpMap.end()) { mPumpMap.erase(found); } // If this instance is one we created, also remove it from mOurPumps so we // won't try again to delete it later! PumpSet::iterator psfound = mOurPumps.find(const_cast<LLEventPump*>(&pump)); if (psfound != mOurPumps.end()) { mOurPumps.erase(psfound); } } LLEventPumps::~LLEventPumps() { // On destruction, delete every LLEventPump we instantiated (via // obtain()). CAREFUL: deleting an LLEventPump calls its destructor, which // calls unregister(), which removes that LLEventPump instance from // mOurPumps. So an iterator loop over mOurPumps to delete contained // LLEventPump instances is dangerous! Instead, delete them one at a time // until mOurPumps is empty. while (! mOurPumps.empty()) { delete *mOurPumps.begin(); } } /***************************************************************************** * LLEventPump *****************************************************************************/ #if LL_WINDOWS #pragma warning (push) #pragma warning (disable : 4355) // 'this' used in initializer list: yes, intentionally #endif LLEventPump::LLEventPump(const std::string& name, bool tweak): // Register every new instance with LLEventPumps mName(LLEventPumps::instance().registerNew(*this, name, tweak)), mEnabled(true) {} #if LL_WINDOWS #pragma warning (pop) #endif LLEventPump::~LLEventPump() { // Unregister this doomed instance from LLEventPumps LLEventPumps::instance().unregister(*this); } // static data member const LLEventPump::NameList LLEventPump::empty; std::string LLEventPump::inventName(const std::string& pfx) { static long suffix = 0; return STRINGIZE(pfx << suffix++); } LLBoundListener LLEventPump::listen_impl(const std::string& name, const LLEventListener& listener, const NameList& after, const NameList& before) { // Check for duplicate name before connecting listener to mSignal ConnectionMap::const_iterator found = mConnections.find(name); // In some cases the user might disconnect a connection explicitly -- or // might use LLEventTrackable to disconnect implicitly. Either way, we can // end up retaining in mConnections a zombie connection object that's // already been disconnected. Such a connection object can't be // reconnected -- nor, in the case of LLEventTrackable, would we want to // try, since disconnection happens with the destruction of the listener // object. That means it's safe to overwrite a disconnected connection // object with the new one we're attempting. The case we want to prevent // is only when the existing connection object is still connected. if (found != mConnections.end() && found->second.connected()) { throw DupListenerName(std::string("Attempt to register duplicate listener name '") + name + "' on " + typeid(*this).name() + " '" + getName() + "'"); } // Okay, name is unique, try to reconcile its dependencies. Specify a new // "node" value that we never use for an mSignal placement; we'll fix it // later. DependencyMap::node_type& newNode = mDeps.add(name, -1.0, after, before); // What if this listener has been added, removed and re-added? In that // case newNode already has a non-negative value because we never remove a // listener from mDeps. But keep processing uniformly anyway in case the // listener was added back with different dependencies. Then mDeps.sort() // would put it in a different position, and the old newNode placement // value would be wrong, so we'd have to reassign it anyway. Trust that // re-adding a listener with the same dependencies is the trivial case for // mDeps.sort(): it can just replay its cache. DependencyMap::sorted_range sorted_range; try { // Can we pick an order that works including this new entry? sorted_range = mDeps.sort(); } catch (const DependencyMap::Cycle& e) { // No: the new node's after/before dependencies have made mDeps // unsortable. If we leave the new node in mDeps, it will continue // to screw up all future attempts to sort()! Pull it out. mDeps.remove(name); throw Cycle(std::string("New listener '") + name + "' on " + typeid(*this).name() + " '" + getName() + "' would cause cycle: " + e.what()); } // Walk the list to verify that we haven't changed the order. float previous = 0.0, myprev = 0.0; DependencyMap::sorted_iterator mydmi = sorted_range.end(); // need this visible after loop for (DependencyMap::sorted_iterator dmi = sorted_range.begin(); dmi != sorted_range.end(); ++dmi) { // Since we've added the new entry with an invalid placement, // recognize it and skip it. if (dmi->first == name) { // Remember the iterator belonging to our new node, and which // placement value was 'previous' at that point. mydmi = dmi; myprev = previous; continue; } // If the new node has rearranged the existing nodes, we'll find // that their placement values are no longer in increasing order. if (dmi->second < previous) { // This is another scenario in which we'd better back out the // newly-added node from mDeps -- but don't do it yet, we want to // traverse the existing mDeps to report on it! // Describe the change to the order of our listeners. Copy // everything but the newest listener to a vector we can sort to // obtain the old order. typedef std::vector< std::pair<float, std::string> > SortNameList; SortNameList sortnames; for (DependencyMap::sorted_iterator cdmi(sorted_range.begin()), cdmend(sorted_range.end()); cdmi != cdmend; ++cdmi) { if (cdmi->first != name) { sortnames.push_back(SortNameList::value_type(cdmi->second, cdmi->first)); } } std::sort(sortnames.begin(), sortnames.end()); std::ostringstream out; out << "New listener '" << name << "' on " << typeid(*this).name() << " '" << getName() << "' would move previous listener '" << dmi->first << "'\nwas: "; SortNameList::const_iterator sni(sortnames.begin()), snend(sortnames.end()); if (sni != snend) { out << sni->second; while (++sni != snend) { out << ", " << sni->second; } } out << "\nnow: "; DependencyMap::sorted_iterator ddmi(sorted_range.begin()), ddmend(sorted_range.end()); if (ddmi != ddmend) { out << ddmi->first; while (++ddmi != ddmend) { out << ", " << ddmi->first; } } // NOW remove the offending listener node. mDeps.remove(name); // Having constructed a description of the order change, inform caller. throw OrderChange(out.str()); } // This node becomes the previous one. previous = dmi->second; } // We just got done with a successful mDeps.add(name, ...) call. We'd // better have found 'name' somewhere in that sorted list! assert(mydmi != sorted_range.end()); // Four cases: // 0. name is the only entry: placement 1.0 // 1. name is the first of several entries: placement (next placement)/2 // 2. name is between two other entries: placement (myprev + (next placement))/2 // 3. name is the last entry: placement ceil(myprev) + 1.0 // Since we've cleverly arranged for myprev to be 0.0 if name is the // first entry, this folds down to two cases. Case 1 is subsumed by // case 2, and case 0 is subsumed by case 3. So we need only handle // cases 2 and 3, which means we need only detect whether name is the // last entry. Increment mydmi to see if there's anything beyond. if (++mydmi != sorted_range.end()) { // The new node isn't last. Place it between the previous node and // the successor. newNode = (myprev + mydmi->second)/2.0; } else { // The new node is last. Bump myprev up to the next integer, add // 1.0 and use that. newNode = std::ceil(myprev) + 1.0; } // Now that newNode has a value that places it appropriately in mSignal, // connect it. LLBoundListener bound = mSignal.connect(newNode, listener); mConnections[name] = bound; return bound; } LLBoundListener LLEventPump::getListener(const std::string& name) const { ConnectionMap::const_iterator found = mConnections.find(name); if (found != mConnections.end()) { return found->second; } // not found, return dummy LLBoundListener return LLBoundListener(); } void LLEventPump::stopListening(const std::string& name) { ConnectionMap::iterator found = mConnections.find(name); if (found != mConnections.end()) { found->second.disconnect(); mConnections.erase(found); } // We intentionally do NOT remove this name from mDeps. It may happen that // the same listener with the same name and dependencies will jump on and // off this LLEventPump repeatedly. Keeping a cache of dependencies will // avoid a new dependency sort in such cases. } /***************************************************************************** * LLEventStream *****************************************************************************/ bool LLEventStream::post(const LLSD& event) { if (! mEnabled) return false; // Let caller know if any one listener handled the event. This is mostly // useful when using LLEventStream as a listener for an upstream // LLEventPump. return mSignal(event); } /***************************************************************************** * LLEventQueue *****************************************************************************/ bool LLEventQueue::post(const LLSD& event) { if (mEnabled) { // Defer sending this event by queueing it until flush() mEventQueue.push_back(event); } // Unconditionally return false. We won't know until flush() whether a // listener claims to have handled the event -- meanwhile, don't block // other listeners. return false; } void LLEventQueue::flush() { // Consider the case when a given listener on this LLEventQueue posts yet // another event on the same queue. If we loop over mEventQueue directly, // we'll end up processing all those events during the same flush() call // -- rather like an EventStream. Instead, copy mEventQueue and clear it, // so that any new events posted to this LLEventQueue during flush() will // be processed in the *next* flush() call. EventQueue queue(mEventQueue); mEventQueue.clear(); for ( ; ! queue.empty(); queue.pop_front()) { mSignal(queue.front()); } } /***************************************************************************** * LLListenerOrPumpName *****************************************************************************/ LLListenerOrPumpName::LLListenerOrPumpName(const std::string& pumpname): // Look up the specified pumpname, and bind its post() method as our listener mListener(boost::bind(&LLEventPump::post, boost::ref(LLEventPumps::instance().obtain(pumpname)), _1)) { } LLListenerOrPumpName::LLListenerOrPumpName(const char* pumpname): // Look up the specified pumpname, and bind its post() method as our listener mListener(boost::bind(&LLEventPump::post, boost::ref(LLEventPumps::instance().obtain(pumpname)), _1)) { } bool LLListenerOrPumpName::operator()(const LLSD& event) const { if (! mListener) { throw Empty("attempting to call uninitialized"); } return (*mListener)(event); } void LLReqID::stamp(LLSD& response) const { if (! (response.isUndefined() || response.isMap())) { // If 'response' was previously completely empty, it's okay to // turn it into a map. If it was already a map, then it should be // okay to add a key. But if it was anything else (e.g. a scalar), // assigning a ["reqid"] key will DISCARD the previous value, // replacing it with a map. That would be Bad. LL_INFOS("LLReqID") << "stamp(" << mReqid << ") leaving non-map response unmodified: " << response << LL_ENDL; return; } LLSD oldReqid(response["reqid"]); if (! (oldReqid.isUndefined() || llsd_equals(oldReqid, mReqid))) { LL_INFOS("LLReqID") << "stamp(" << mReqid << ") preserving existing [\"reqid\"] value " << oldReqid << " in response: " << response << LL_ENDL; return; } response["reqid"] = mReqid; }