retain is coming git status!

src/StringIndexer.h

@@ -107,6 +107,8 @@ class IndexedString
       index = source.index;
     }
 
+    IndexedString(IndexedString&& i) : index(i.index) {}
+
     IndexedString(const char* str, uint8_t len)
     {
       index=StringIndexer::strToIndex(str, len);

src/TinyMqtt.cpp

@@ -15,8 +15,10 @@ int TinyMqtt::debug=2;
   std::map<MqttMessage::Type, int> MqttClient::counters;
 #endif
 
-MqttBroker::MqttBroker(uint16_t port)
+MqttBroker::MqttBroker(uint16_t port, uint8_t max_retain_size)
 {
+  debug("New broker" << port);
+  retain_size = max_retain_size;
   server = new TcpServer(port);
 #ifdef TINY_MQTT_ASYNC
   server->onClient(onClient, this);
@@ -211,9 +213,19 @@ void MqttBroker::loop()
   }
 }
 
-MqttError MqttBroker::subscribe(const Topic& topic, uint8_t qos)
+// Obvioulsy called when the broker is connected to another broker.
+MqttError MqttBroker::subscribe(MqttClient* client, const Topic& topic, uint8_t qos)
 {
-  debug("MqttBroker::subscribe");
+  debug("MqttBroker::subscribe to " << topic.str() << ", retained=" << retained.size() );
+  for(auto& [retained_topic, retain]: retained)
+  {
+    debug("  retained: " << retained_topic.str());
+    if (topic.matches(retained_topic))
+    {
+      debug("  -> sending");
+      client->publishIfSubscribed(retained_topic, retain.msg);
+    }
+  }
   if (remote_broker && remote_broker->connected())
   {
     return remote_broker->subscribe(topic, qos);
@@ -221,10 +233,12 @@ MqttError MqttBroker::subscribe(const Topic& topic, uint8_t qos)
   return MqttNowhereToSend;
 }
 
-MqttError MqttBroker::publish(const MqttClient* source, const Topic& topic, MqttMessage& msg) const
+MqttError MqttBroker::publish(const MqttClient* source, const Topic& topic, MqttMessage& msg)
 {
   MqttError retval = MqttOk;
 
+  retain(topic, msg);
+
   debug("MqttBroker::publish");
   int i=0;
   for(auto client: clients)
@@ -391,13 +405,13 @@ MqttError MqttClient::subscribe(Topic topic, uint8_t qos)
 
   subscriptions.insert(topic);
 
-  if (local_broker==nullptr) // remote broker
+  if (local_broker==nullptr) // connected to a remote broker
   {
     return sendTopic(topic, MqttMessage::Type::Subscribe, qos);
   }
   else
   {
-    return local_broker->subscribe(topic, qos);
+    return local_broker->subscribe(this, topic, qos);
   }
   return ret;
 }
@@ -568,7 +582,7 @@ void MqttClient::processMessage(MqttMessage* mesg)
             }
             else
               qoss.push_back(qos);
-            subscriptions.insert(topic);
+            subscribe(topic);
           }
           else
           {
@@ -618,8 +632,8 @@ void MqttClient::processMessage(MqttMessage* mesg)
           #if TINY_MQTT_DEBUG
             if (TinyMqtt::debug >= 2)
             {
-              Console << (isSubscribedTo(published) ? "not" : "") << " subscribed.\n";
+              Console << (isSubscribedTo(published) ? "not" : "") << " subscribed.\r\n";
-              Console << "has " << (callback ? "" : "no ") << " callback.\n";
+              Console << "has " << (callback ? "" : "no ") << " callback.\r\n";
             }
           #endif
           if (callback and isSubscribedTo(published))
@@ -728,9 +742,9 @@ bool Topic::matches(const Topic& topic) const
 
 
 // publish from local client
-MqttError MqttClient::publish(const Topic& topic, const char* payload, size_t pay_length)
+MqttError MqttClient::publish(const Topic& topic, const char* payload, size_t pay_length, bool retain)
 {
-  MqttMessage msg(MqttMessage::Publish);
+  MqttMessage msg(MqttMessage::Publish, retain ? 1 : 0);
   msg.add(topic);
   msg.add(payload, pay_length, false);
   msg.complete();
@@ -894,6 +908,35 @@ MqttError MqttMessage::sendTo(MqttClient* client)
   return MqttOk;
 }
 
+void MqttBroker::retainDrop()
+{
+  if (retained.size() >= retain_size)
+  {
+    std::map<Topic, Retain>::iterator oldest = retained.begin();
+    auto it = oldest;
+    while(++it != retained.end())
+    {
+      if (oldest->second.timestamp > it->second.timestamp)
+        oldest = it;
+    }
+    retained.erase(oldest);
+  }
+}
+
+void MqttBroker::retain(const Topic& topic, const MqttMessage& msg)
+{
+  debug("MqttBroker::retain msg_type=" << _HEX(msg.type()));
+  if (retain_size==0 or msg.type() != MqttMessage::Publish) return;
+  if (msg.flags() & 1)  // flag RETAIN
+  {
+    debug("  retaining " << topic.str());
+    if (retained.find(topic) == retained.end()) retainDrop();
+    // FIXME if payload size == 0 remove message from retained
+    Retain r(micros(), msg);
+    retained.insert({ topic, std::move(r)});
+  }
+}
+
 void MqttMessage::hexdump(const char* prefix) const
 {
   (void)prefix;

src/TinyMqtt.h

@@ -121,7 +121,10 @@ class MqttMessage
       return (*bun << 8) | bun[1]; }
 
     MqttMessage() { reset(); }
-    MqttMessage(Type t, uint8_t bits_d3_d0=0) { create(t); buffer[0] |= bits_d3_d0; }
+    MqttMessage(Type t, uint8_t bits_d3_d0=0) { create(t); buffer[0] |= (bits_d3_d0 & 0xF); }
+    MqttMessage(const MqttMessage& m)
+      : buffer(m.buffer), vheader(m.vheader), size(m.size), state(m.state) {}
+
     void incoming(char byte);
     void add(char byte) { incoming(byte); }
     void add(const char* p, size_t len, bool addLength=true );
@@ -156,6 +159,15 @@ class MqttMessage
     MqttError sendTo(MqttClient*);
     void hexdump(const char* prefix=nullptr) const;
 
+    MqttMessage& operator = (MqttMessage&& m)
+    {
+      buffer = std::move(m.buffer);
+      vheader = m.vheader;
+      size = m.size;
+      state = m.state;
+      return *this;
+    }
+
   private:
     void encodeLength();
 
@@ -228,11 +240,11 @@ class MqttClient
     };
 
     // Publish from client to the world
-    MqttError publish(const Topic&, const char* payload, size_t pay_length);
+    MqttError publish(const Topic&, const char* payload, size_t pay_length, bool retain=false);
-    MqttError publish(const Topic& t, const char* payload) { return publish(t, payload, strlen(payload)); }
+    MqttError publish(const Topic& t, const char* payload, bool retain=false) { return publish(t, payload, strlen(payload), retain); }
-    MqttError publish(const Topic& t, const String& s) { return publish(t, s.c_str(), s.length()); }
+    MqttError publish(const Topic& t, const String& s, bool retain=false) { return publish(t, s.c_str(), s.length(), retain); }
-    MqttError publish(const Topic& t, const string& s) { return publish(t,s.c_str(),s.length());}
+    MqttError publish(const Topic& t, const string& s, bool retain=false) { return publish(t,s.c_str(),s.length(), retain);}
-    MqttError publish(const Topic& t) { return publish(t, nullptr, 0);};
+    MqttError publish(const Topic& t, bool retain=false) { return publish(t, nullptr, 0, retain);};
 
     MqttError subscribe(Topic topic, uint8_t qos=0);
     MqttError unsubscribe(Topic topic);
@@ -325,7 +337,7 @@ class MqttBroker
   };
   public:
     // TODO limit max number of clients
-    MqttBroker(uint16_t port);
+    MqttBroker(uint16_t port, uint8_t retain_size=0);
     ~MqttBroker();
 
     void begin() { server->begin(); }
@@ -337,6 +349,7 @@ class MqttBroker
     bool connected() const { return state == Connected; }
 
     size_t clientsCount() const { return clients.size(); }
+    void retain(uint8_t size) { retain_size = size; }
 
     void dump(string indent="")
     {
@@ -356,10 +369,9 @@ class MqttBroker
     bool checkPassword(const char* password, uint8_t len) const
     { return compareString(auth_password, password, len); }
 
+    MqttError publish(const MqttClient* source, const Topic& topic, MqttMessage& msg);
 
-    MqttError publish(const MqttClient* source, const Topic& topic, MqttMessage& msg) const;
+    MqttError subscribe(MqttClient*, const Topic& topic, uint8_t qos);
-
-    MqttError subscribe(const Topic& topic, uint8_t qos);
 
     // For clients that are added not by the broker itself (local clients)
     void addClient(MqttClient* client);
@@ -376,4 +388,26 @@ class MqttBroker
     MqttClient* remote_broker = nullptr;
 
     State state = Disconnected;
+
+    void retain(const Topic& topic, const MqttMessage& msg);
+    void retainDrop();
+
+    struct Retain
+    {
+      Retain(unsigned long ts, const MqttMessage& m) : timestamp(ts), msg(m) {}
+      Retain(Retain&& r) : timestamp(r.timestamp), msg(std::move(r.msg)) {}
+
+      Retain& operator=(Retain&& r)
+      {
+        timestamp = r.timestamp;
+        msg = std::move(r.msg);
+        return *this;
+      }
+
+      unsigned long timestamp;
+      MqttMessage msg;
+    };
+
+    std::map<Topic, Retain> retained;
+    uint8_t retain_size;
 };