Implement unsubscribe and drain in publish

src/TopicTreeDraft.h

@@ -120,6 +120,11 @@ private:
 
     /* Should be getData and commit? */
     void publish(Topic *iterator, size_t start, size_t stop, std::string_view topic, std::string_view message) {
+        /* If we already have 64 triggered topics make sure to drain it here */
+        if (numTriggeredTopics == 64) {
+            drain();
+        }
+
         for (; stop != std::string::npos; start = stop + 1) {
             stop = topic.find('/', start);
             std::string_view segment = topic.substr(start, stop - start);
@@ -235,10 +240,39 @@ public:
         messageId++;
     }
 
-    /* Rarely used, probably */
-    void unsubscribe(std::string_view topic, Subscriber *subscriber) {
+    /* Returns whether we were subscribed prior */
+    bool unsubscribe(std::string_view topic, Subscriber *subscriber) {
         /* Subscribers are likely to have very few subscriptions (20 or fewer) */
+        if (subscriber) {
+            /* Lookup exact Topic ptr from string */
+            Topic *iterator = root;
+            for (size_t start = 0, stop = 0; stop != std::string::npos; start = stop + 1) {
+                stop = topic.find('/', start);
+                std::string_view segment = topic.substr(start, stop - start);
 
+                std::map<std::string_view, Topic *>::iterator it = iterator->children.find(segment);
+                if (it == iterator->children.end()) {
+                    /* This topic does not even exist */
+                    return false;
+                }
+
+                iterator = it->second;
+            }
+
+            /* Try and remove this topic from our list */
+            for (auto it = subscriber->subscriptions.begin(); it != subscriber->subscriptions.end(); it++) {
+                if (*it == iterator) {
+                    /* Remove topic ptr from our list */
+                    subscriber->subscriptions.erase(it);
+
+                    /* Remove us from Topic's subs */
+                    iterator->subs.erase(subscriber);
+                    trimTree(iterator);
+                    return true;
+                }
+            }
+        }
+        return false;
     }
 
     /* Can be called with nullptr, ignore it then */

src/WebSocket.h

@@ -154,6 +154,17 @@ public:
         webSocketContextData->topicTree.subscribe(topic, webSocketData->subscriber);
     }
 
+    /* Unsubscribe from a topic, returns true if we were subscribed */
+    bool unsubscribe(std::string_view topic) {
+        WebSocketContextData<SSL> *webSocketContextData = (WebSocketContextData<SSL> *) us_socket_context_ext(SSL,
+            (us_socket_context_t *) us_socket_context(SSL, (us_socket_t *) this)
+        );
+
+        WebSocketData *webSocketData = (WebSocketData *) us_socket_ext(SSL, (us_socket_t *) this);
+
+        return webSocketContextData->topicTree.unsubscribe(topic, webSocketData->subscriber);
+    }
+
     /* Publish a message to a topic according to MQTT rules and syntax */
     void publish(std::string_view topic, std::string_view message, OpCode opCode = OpCode::TEXT, bool compress = false) {
         WebSocketContextData<SSL> *webSocketContextData = (WebSocketContextData<SSL> *) us_socket_context_ext(SSL,