server: rework cleanup of connection, channel, and operation

src/serverchan.cpp

@@ -36,6 +36,30 @@ ServerChan::~ServerChan() {
     assert(!onClose);
 }
 
+/* reached from:
+ * 1. connection close
+ * 2. DESTROY_CHANNEL
+ * 3. local user calls ServerChannelControl::close()
+ */
+void ServerChan::cleanup()
+{
+    if(state==ServerChan::Destroy)
+        return;
+    state = ServerChan::Destroy;
+
+    {
+        auto ops(std::move(opByIOID));
+        for(auto& op : ops) {
+            // removes from conn->opByIOID
+            op.second->cleanup();
+        }
+    }
+
+    auto fn(std::move(onClose));
+    if(fn)
+        fn("");
+}
+
 ServerChannelControl::ServerChannelControl(const std::shared_ptr<ServerConn> &conn, const std::shared_ptr<ServerChan>& channel)
     :server::ChannelControl(channel->name, conn->cred, None)
     ,server(conn->iface->server->internal_self)
@@ -104,45 +128,6 @@ void ServerChannelControl::onClose(std::function<void(const std::string&)>&& fn)
     });
 }
 
-static
-void ServerChannel_shutdown(const std::shared_ptr<ServerChan>& chan)
-{
-    if(chan->state==ServerChan::Destroy)
-        return;
-
-    chan->state = ServerChan::Destroy;
-
-    if(auto conn = chan->conn.lock()) {
-
-        conn->chanBySID.erase(chan->sid);
-
-        for(auto& pair : chan->opByIOID) {
-            auto op = pair.second;
-            if(op->state==ServerOp::Dead)
-                continue;
-
-            if(op->state==ServerOp::Executing && op->onCancel)
-                op->onCancel();
-
-            op->state = ServerOp::Dead;
-
-            if(op->onClose) {
-                auto fn(std::move(op->onClose));
-                fn("");
-            }
-
-            conn->opByIOID.erase(op->ioid);
-        }
-    }
-
-    chan->opByIOID.clear();
-
-    if(chan->onClose) {
-        auto fn(std::move(chan->onClose));
-        fn("");
-    }
-}
-
 void ServerChannelControl::close()
 {
     // fail soft if server stopped, or channel/connection already closed
@@ -167,7 +152,8 @@ void ServerChannelControl::close()
             conn->statTx += 16u;
             ch->statTx += 16u;
         }
-        ServerChannel_shutdown(ch);
+
+        ch->cleanup();
     });
 }
 
@@ -407,10 +393,7 @@ void ServerConn::handle_DESTROY_CHANNEL()
                    unsigned(sid), unsigned(chan->cid), unsigned(cid), chan->name.c_str());
     }
 
-    ServerChannel_shutdown(chan);
-
-    assert(chan.use_count()==1); // we only take transient refs on this thread
-    // ServerChannel is delete'd
+    chan->cleanup();
 
     {
         auto tx = bufferevent_get_output(bev.get());