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Diffstat (limited to 'indra/llcommon/llevents.cpp')
| -rw-r--r-- | indra/llcommon/llevents.cpp | 501 |
1 files changed, 501 insertions, 0 deletions
diff --git a/indra/llcommon/llevents.cpp b/indra/llcommon/llevents.cpp new file mode 100644 index 0000000000..eb380ba7c8 --- /dev/null +++ b/indra/llcommon/llevents.cpp @@ -0,0 +1,501 @@ +/** + * @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 + +/***************************************************************************** +* 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 +{ + RegisterFlush(): + pumps(LLEventPumps::instance()), + mainloop(pumps.obtain("mainloop")), + name("flushLLEventQueues") + { + mainloop.listen(name, boost::bind(&RegisterFlush::flush, this, _1)); + } + bool flush(const LLSD&) + { + pumps.flush(); + return false; + } + ~RegisterFlush() + { + mainloop.stopListening(name); + } + LLEventPumps& pumps; + LLEventPump& mainloop; + const std::string name; +}; +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; + +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); +} |