MessageRouter.hpp

//
// Copyright (c) 2010-2021 60East Technologies Inc., All Rights Reserved.
//
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#ifndef _MESSAGEROUTER_HPP_
#define _MESSAGEROUTER_HPP_
#include <map>
#include "ampscrc.hpp"
#include "util.hpp"
#include "Message.hpp"

namespace AMPS
{
template <typename Func, typename Object>
class Handler
{
protected:
 friend class MessageStream;
 Func _func;
 void* _userData;
#ifdef AMPS_USE_FUNCTIONAL
 std::function<void(Object)> _callable;
#endif
 bool _isValid;

public:
 // No op function for handlers
 static void noOpHandler(Object) {;}

 typedef Func FunctionType;
 Handler() : _func(NULL), _userData(NULL)
#ifdef AMPS_USE_FUNCTIONAL
 , _callable(Handler<Func,Object>::noOpHandler)
#endif
 , _isValid(false)
 {
 }

 Handler(Func func_, void* userData_)
 : _func(func_), _userData(userData_)
#ifdef AMPS_USE_FUNCTIONAL
 , _callable(noOpHandler)
#endif
 , _isValid(true)
 {
 }

 Handler(const Handler& orig_)
 : _func(orig_._func), _userData(orig_._userData)
#ifdef AMPS_USE_FUNCTIONAL
 , _callable(orig_._callable)
#endif
 , _isValid(true)
 {
 }
#ifdef AMPS_USE_FUNCTIONAL
 template <typename T>
 Handler(const T& callback_)
 : _func(NULL), _userData(NULL), _callable(callback_), _isValid(true)
 {
 }
#endif
 void invoke(Object message)
 {
 if (_func)
 _func(message, _userData);
#ifdef AMPS_USE_FUNCTIONAL
 else
 _callable(message);
#endif
 }

 Handler& operator=(const Handler& rhs_)
 {
 if (this != &rhs_)
 {
 _func = rhs_._func;
 _userData = rhs_._userData;
#ifdef AMPS_USE_FUNCTIONAL
 _callable = rhs_._callable;
#endif
 _isValid = rhs_._isValid;
 }
 return *this;
 }

 bool isValid(void) const { return _isValid; }
 Func function(void) const { return _func; }
 void* userData(void) const { return _userData; }
};
class Message;
typedef void(*MessageHandlerFunc)(const Message&, void* userData);

typedef Handler<MessageHandlerFunc, const Message&> MessageHandler;

class MessageRouter
{
private:
 MessageHandler _emptyMessageHandler;
 typedef amps_uint64_t (*CRCFunction)(const char*, size_t, amps_uint64_t);
 // Function used to calculate the CRC if one is used
 CRCFunction _crc;

 class MessageRoute
 {
 MessageHandler _messageHandler;
 unsigned _requestedAcks, _systemAcks, _terminationAck;
 public:
 MessageRoute() : _requestedAcks(0), _systemAcks(0), _terminationAck(0) {;}
 MessageRoute(const MessageRoute& rhs_) :
 _messageHandler(rhs_._messageHandler),
 _requestedAcks (rhs_._requestedAcks),
 _systemAcks (rhs_._systemAcks),
 _terminationAck(rhs_._terminationAck)
 {;}
 const MessageRoute& operator=(const MessageRoute& rhs_)
 {
 _messageHandler = rhs_._messageHandler;
 _requestedAcks = rhs_._requestedAcks;
 _systemAcks = rhs_._systemAcks;
 _terminationAck = rhs_._terminationAck;
 return *this;
 }
 MessageRoute(MessageHandler messageHandler_, unsigned requestedAcks_,
 unsigned systemAcks_, bool isSubscribe_) :
 _messageHandler(messageHandler_),
 _requestedAcks(requestedAcks_),
 _systemAcks(systemAcks_),
 _terminationAck(0)
 {
 if(!isSubscribe_)
 {
 // The ack to terminate the route on is whatever the highest
 // bit set in requestedAcks is.
 unsigned bitCounter = (requestedAcks_|systemAcks_)>>1;
 _terminationAck = 1;
 while(bitCounter > 0) { bitCounter>>=1; _terminationAck<<=1; }
 }
 }

 // Deliver an ack to registered handler if the ack type was requested
 unsigned deliverAck(const Message& message_, unsigned ackType_)
 {
 if ( (_requestedAcks & ackType_) == 0) return 0;
 try {
 _messageHandler.invoke(message_);
 } catch (std::exception &ex)
 {
 std::cerr << ex.what() << std::endl;
 }
 return 1;
 }
 bool isTerminationAck(unsigned ackType_) const
 {
 return ackType_ == _terminationAck;
 }
 unsigned deliverData(const Message& message_)
 {
 _messageHandler.invoke(message_);
 return 1;
 }
 const MessageHandler& getMessageHandler() const
 {
 return _messageHandler;
 }
 MessageHandler& getMessageHandler()
 {
 return _messageHandler;
 }
 };

public:
 MessageRouter()
 : _previousCommandId(0),
 _lookupGenerationCount(0),
 _generationCount(0)
 {
#ifndef AMPS_SSE_42
 _crc = AMPS::CRC<0>::crcNoSSE;
#else
 if(AMPS::CRC<0>::isSSE42Enabled())
 {
 _crc = AMPS::CRC<0>::crc;
 }
 else
 {
 _crc = AMPS::CRC<0>::crcNoSSE;
 }
#endif
 }

 int addRoute(const Field& commandId_, const AMPS::MessageHandler& messageHandler_,
 unsigned requestedAcks_, unsigned systemAcks_, bool isSubscribe_)
 {
 Lock<Mutex> lock(_lock);
 RouteMap::iterator i = _routes.find(commandId_);
 if (i == _routes.end()) {
 _routes[commandId_.deepCopy()] = MessageRoute(messageHandler_, requestedAcks_, systemAcks_, isSubscribe_);
 return 1;
 }
 else {
 // Only replace a non-subscribe with a subscribe
 if (isSubscribe_ && !i->second.isTerminationAck(0))
 {
 void *routeData = i->second.getMessageHandler().userData();;
 i->second = MessageRoute(messageHandler_, requestedAcks_, systemAcks_, isSubscribe_);
 if (routeData)
 {
 Unlock<Mutex> u(_lock);
 amps_invoke_remove_route_function(routeData);
 }
 return 1;
 }
 }
 return 0;
 }

 // returns true if a route was removed.
 bool removeRoute(const Field& commandId_)
 {
 Lock<Mutex> lock(_lock);
 RouteMap::iterator i = _routes.find(commandId_);
 if (i == _routes.end()) return false;
 return _removeRoute(i);
 }

 void clear()
 {
 AMPS_FETCH_ADD(&_generationCount,1);
 std::vector<void*> removeData;
 {
 Lock<Mutex> lock(_lock);
 for (RouteMap::iterator i = _routes.begin(); i != _routes.end(); ++i)
 {
 // Make a non-const copy of Field and clear it, which will clear i
 // as well but won't actually affect the map, which is unaware that
 // the key's shared pointer has been deleted.
 Field f = i->first;
 void* data = i->second.getMessageHandler().userData();
 removeData.push_back(data);
 f.clear();
 }
 _routes.clear();
 }
 for (size_t i=0; i<removeData.size(); ++i)
 {
 amps_invoke_remove_route_function(removeData[i]);
 }
 }

 // Returns true if a route exists for a single id.
 bool hasRoute(const Field& commandId_) const
 {
 Lock<Mutex> lock(_lock);
 RouteMap::const_iterator it = _routes.find(commandId_);
 return it != _routes.end();
 }

 // Find a single route and return true if here, setting result_ to the handler.
 bool getRoute(const Field& commandId_, MessageHandler& result_) const
 {
 Lock<Mutex> lock(_lock);
 RouteMap::const_iterator it = _routes.find(commandId_);
 if (it != _routes.end())
 {
 result_ = it->second.getMessageHandler();
 return true;
 }
 else
 {
 result_ = _emptyMessageHandler;
 return false;
 }
 }

 // RouteCache is the result type for a parseRoutes(); we do extra work
 // to avoid hitting the map or its lock when the subids field on
 // publish messages does not change.
 struct RouteLookup
 {
 size_t idOffset;
 size_t idLength;
 MessageHandler handler;
 };
 class RouteCache : public std::vector<RouteLookup>
 {
 RouteCache(const RouteCache&);
 void operator=(const RouteCache&);
 public:
 RouteCache(void)
 : _generationCount(0),
 _hashVal(0)
 {;}

 void invalidateCache(void)
 {
 _generationCount = 0;
 _hashVal = 0;
 clear();
 }
 void invalidateCache(ATOMIC_TYPE generationCount_, amps_uint64_t hashVal_)
 {
 _generationCount = generationCount_;
 _hashVal = hashVal_;
 clear();
 }

 bool isCacheHit(ATOMIC_TYPE generationCount_, amps_uint64_t hashVal_) const
 {
 return _generationCount == generationCount_ && _hashVal == hashVal_;
 }

 private:
 ATOMIC_TYPE _generationCount;
 amps_uint64_t _hashVal;
 };

 // Parses the command id list into the route lookup vector and assigns
 // the found handlers into the list. Only intended to be called by the
 // message handler thread. Returns the number of command/sub IDs parsed.
 size_t parseRoutes(const Field& commandIdList_, RouteCache& result_)
 {
 // Super shortcut: if the whole subID list is the same as the previous one,
 // then assume the result_ contains all the right handlers already, and that
 // the offsets and lengths of subIds are unchanged.
 amps_uint64_t listHash = _crc(commandIdList_.data(), commandIdList_.len(), 0);
 if (result_.isCacheHit(_generationCount, listHash))
 {
 return result_.size();
 }
 result_.invalidateCache(_generationCount, listHash);

 // Lock required now that we'll be using the route map.
 Lock<Mutex> lockGuard(_lock);
 size_t resultCount = 0;
 const char* pStart = commandIdList_.data();
 for(const char* p = pStart, *e = commandIdList_.len() + pStart; p < e;
 ++p, ++resultCount)
 {
 const char* delimiter = p;
 while(delimiter != e && *delimiter != ',')
 {
 ++delimiter;
 }
 AMPS::Field subId(p, (size_t)(delimiter-p));
 result_.push_back(RouteLookup());
 // Push back and then copy over fields; would emplace_back if available on
 // all supported compilers.
 RouteLookup& result = result_[resultCount];
 result.idOffset = (size_t)(p - pStart);
 result.idLength = (size_t)(delimiter - p);

 RouteMap::const_iterator it = _routes.find(subId);
 if (it != _routes.end())
 {
 result.handler = it->second.getMessageHandler();
 }
 else
 {
 result.handler = _emptyMessageHandler;
 }
 p = delimiter;
 }
 return resultCount;
 }
 unsigned deliverAck(const Message& ackMessage_, unsigned ackType_)
 {
 assert(ackMessage_.getCommand() == "ack");
 unsigned messagesDelivered = 0;
 Field key;

 // Call _deliverAck, which will deliver to any waiting handlers
 // AND remove the route if it's a termination ack
 if(key = ackMessage_.getCommandId(), !key.empty())
 {
 messagesDelivered += _deliverAck(ackMessage_, ackType_, key);
 }
 if(key = ackMessage_.getQueryID(),
 !key.empty() && messagesDelivered == 0)
 {
 messagesDelivered += _deliverAck(ackMessage_, ackType_, key);
 }
 if(key = ackMessage_.getSubscriptionId(),
 !key.empty() && messagesDelivered == 0)
 {
 messagesDelivered += _deliverAck(ackMessage_, ackType_, key);
 }
 return messagesDelivered;
 }

 // deliverData may only be called by the message handler thread.
 unsigned deliverData(const Message& dataMessage_, const Field& commandId_)
 {
 unsigned messagesDelivered = 0;
 amps_uint64_t hval = _crc(commandId_.data(), commandId_.len(), 0);
 if(_previousCommandId == hval &&
 _lookupGenerationCount == _generationCount)
 {
 messagesDelivered += _previousHandler.deliverData(dataMessage_);
 }
 else
 {
 Lock<Mutex> lock(_lock);
 RouteMap::iterator it = _routes.find(commandId_);
 if(it != _routes.end())
 {
 _previousCommandId = hval;
 _lookupGenerationCount = _generationCount;
 _previousHandler = it->second;
 messagesDelivered += it->second.deliverData(dataMessage_);
 }
 }
 return messagesDelivered;
 }

 void invalidateCache(void)
 {
 _previousCommandId = 0;
 }

 void unsubscribeAll(void)
 {
 AMPS_FETCH_ADD(&_generationCount,1);
 std::vector<Field> removeIds;
 std::vector<void*> removeData;
 Lock<Mutex> lock(_lock);
 for (RouteMap::iterator it = _routes.begin(); it != _routes.end(); ++it)
 {
 if (it->second.isTerminationAck(0))
 {
 removeIds.push_back(it->first);
 removeData.push_back(it->second.getMessageHandler().userData());
 }
 }
 for (size_t i=0; i<removeIds.size(); ++i)
 {
 // it can't be end() b/c we have the lock and found id above
 RouteMap::iterator it = _routes.find(removeIds[i]);
 // Make a non-const copy of Field and clear it, which will clear i as well
 Field f = it->first; // -V783
 f.clear();
 _routes.erase(it);
 }
 Unlock<Mutex> u(_lock);
 for (size_t i=0; i<removeData.size(); ++i)
 {
 amps_invoke_remove_route_function(removeData[i]);
 }
 }

private:
 typedef std::map<Field, MessageRoute> RouteMap;
 RouteMap _routes;
 mutable Mutex _lock;

 MessageRoute _previousHandler;
 amps_uint64_t _previousCommandId;
 mutable ATOMIC_TYPE _lookupGenerationCount;
 mutable ATOMIC_TYPE _generationCount;

 // Deliver the ack to any waiting handlers
 // AND remove the route if it's a termination ack
 unsigned _deliverAck(const Message& ackMessage_, unsigned ackType_, Field& commandId_)
 {
 Lock<Mutex> lock(_lock);
 unsigned messagesDelivered = 0;
 RouteMap::iterator it = _routes.find(commandId_);
 if(it!=_routes.end())
 {
 MessageRoute& route = it->second;
 messagesDelivered += route.deliverAck(ackMessage_, ackType_);
 if(route.isTerminationAck(ackType_))
 {
 _removeRoute(it);
 ++messagesDelivered;
 }
 }
 return messagesDelivered;
 }
 unsigned _processAckForRemoval(unsigned ackType_, Field& commandId_)
 {
 Lock<Mutex> lock(_lock);
 RouteMap::iterator it = _routes.find(commandId_);
 if(it!=_routes.end())
 {
 MessageRoute& route = it->second;
 if(route.isTerminationAck(ackType_))
 {
 _removeRoute(it);
 return 1U;
 }
 }
 return 0U;
 }

 // returns true if a route was removed.
 bool _removeRoute(RouteMap::iterator& it_)
 {
 // Called with lock already held
 AMPS_FETCH_ADD(&_generationCount,1);
 // Make a non-const copy of Field and clear it, which will clear i as well
 Field f = it_->first;
 void* routeData = it_->second.getMessageHandler().userData();
 _routes.erase(it_);
 f.clear();
 if (routeData)
 {
 Unlock<Mutex> u(_lock);
 amps_invoke_remove_route_function(routeData);
 }
 return true;
 }

};


}

#endif