Change MaybeGetLoop to a virtual member func

Minor simplification.

llarp/ev/ev.hpp

@@ -11,6 +11,11 @@
 #include <future>
 #include <utility>
 
+namespace uvw
+{
+  class Loop;
+}
+
 namespace llarp
 {
   struct SockAddr;
@@ -214,6 +219,14 @@ namespace llarp
     // Returns true if called from within the event loop thread, false otherwise.
     virtual bool
     inEventLoop() const = 0;
+
+    // Returns the uvw::Loop *if* this event loop is backed by a uvw event loop (i.e. the default),
+    // nullptr otherwise.  (This base class default always returns nullptr).
+    virtual std::shared_ptr<uvw::Loop>
+    MaybeGetUVWLoop()
+    {
+      return nullptr;
+    }
   };
 
   using EventLoop_ptr = std::shared_ptr<EventLoop>;

llarp/ev/ev_libuv.cpp

@@ -13,11 +13,9 @@
 namespace llarp::uv
 {
   std::shared_ptr<uvw::Loop>
-  Loop::MaybeGetLoop(const EventLoop_ptr& ptr)
+  Loop::MaybeGetUVWLoop()
   {
-    if (auto* uv = dynamic_cast<Loop*>(ptr.get()))
-      return uv->m_Impl;
-    return nullptr;
+    return m_Impl;
   }
 
   class UVWakeup final : public EventLoopWakeup

llarp/ev/ev_libuv.hpp

@@ -71,8 +71,8 @@ namespace llarp::uv
 
     std::function<void(void)> PumpLL;
 
-    static std::shared_ptr<uvw::Loop>
-    MaybeGetLoop(const EventLoop_ptr&);
+    std::shared_ptr<uvw::Loop>
+    MaybeGetUVWLoop() override;
 
     bool
     inEventLoop() const override;

llarp/quic/client.cpp

@@ -11,7 +11,7 @@
 namespace llarp::quic
 {
   Client::Client(service::ConvoTag tag, service::Endpoint* parent, uint16_t tunnel_port)
-      : Endpoint{parent, uv::Loop::MaybeGetLoop(parent->Loop())}
+      : Endpoint{parent, parent->Loop()->MaybeGetUVWLoop()}
   {
     // Our UDP socket is now set up, so now we initiate contact with the remote QUIC
     Address remote{std::move(tag)};

llarp/service/endpoint.cpp

@@ -83,7 +83,8 @@ namespace llarp
         m_StartupLNSMappings[name] = std::make_pair(range, auth);
       });
 
-      auto loop = uv::Loop::MaybeGetLoop(Router()->loop());
+      auto loop = Router()->loop()->MaybeGetUVWLoop();
+      assert(loop);
       auto callback = [this, loop, ports = conf.m_quicServerPorts](
                           quic::Server& serv, quic::Stream& stream, uint16_t port) {
         if (ports.count(port) == 0)