Stricter pub/sub grouping

src/TopicTree.h

@@ -217,6 +217,11 @@ public:
             }
         }
 
+        /* If this topic is triggered, drain the tree before we join */
+        if (iterator->triggered) {
+            drain();
+        }
+
         /* Add socket to Topic's Set */
         auto [it, inserted] = iterator->subs.insert(subscriber);
 
@@ -253,6 +258,11 @@ public:
             /* Try and remove this topic from our list */
             for (auto it = subscriber->subscriptions.begin(); it != subscriber->subscriptions.end(); it++) {
                 if (*it == iterator) {
+                    /* If this topic is triggered, drain the tree before we leave */
+                    if (iterator->triggered) {
+                        drain();
+                    }
+
                     /* Remove topic ptr from our list */
                     subscriber->subscriptions.erase(it);
 
@@ -270,6 +280,17 @@ public:
     void unsubscribeAll(Subscriber *subscriber) {
         if (subscriber) {
             for (Topic *topic : subscriber->subscriptions) {
+
+                /* This is questionable; we are called mostly from socket close, so we will
+                 * potentially call drain callback with a closed socket, make sure to check there!
+                 * Well it doesn't really matter since there are checks in uSockets but still! */
+
+                /* If this topic is triggered, drain the tree before we leave */
+                if (topic->triggered) {
+                    drain();
+                }
+
+                /* Remove us from the topic's set */
                 topic->subs.erase(subscriber);
                 trimTree(topic);
             }

src/WebSocketContextData.h

@@ -65,6 +65,13 @@ struct WebSocketContextData {
         /* We rely on writing to regular asyncSockets */
         auto *asyncSocket = (AsyncSocket<SSL> *) s->user;
 
+        /* We might be called from unsubscribeAll from close handler of a socket,
+         * so make sure to check if we are a closed socket before trying to send */
+        if (us_socket_is_closed(SSL, (struct us_socket_t *) s->user) || us_socket_is_shut_down(SSL, (struct us_socket_t *) s->user)) {
+            /* Return code means nothing, todo: remove it */
+            return 0;
+        }
+
         /* Check if we now have too much backpressure (todo: don't buffer up before check) */
         if (!maxBackpressure || (unsigned int) asyncSocket->getBufferedAmount() < maxBackpressure) {
             /* Pick uncompressed data track */