Wire up notification mechanism to new handlers.

NEWS

@@ -1,5 +1,6 @@
 7.10.0
  - Deprecate `errorhandler`; replace with lambda-friendly "notice handlers."
+ - Deprecate `notification_receiver`; replace with "notification handlers"
  - Bump minimum CMake version to 3.28. (#874)
  - Fixed error message on clashing transaction focuses. (#879)
  - Don't call`/bin/true`; macOS doesn't have it.  Just call `true`. (#885)

include/pqxx/connection.hxx

@@ -1283,6 +1283,7 @@ private:
   /// 9.0: Replace with just notice handler.
   std::shared_ptr<pqxx::internal::notice_waiters> m_notice_waiters;
 
+  // TODO: Remove these when we retire notification_receiver.
   // TODO: Can we make these movable?
   using receiver_list =
     std::multimap<std::string, pqxx::notification_receiver *>;

include/pqxx/notification.hxx

@@ -61,10 +61,13 @@ public:
    * @param cx Connnection to operate on.
    * @param channel Name of the notification to listen for.
    */
+  [[deprecated("Use pqxx::connection::listen() instead.")]]
   notification_receiver(connection &cx, std::string_view channel);
   /// Register the receiver with a connection.
+  [[deprecated("Use pqxx::connection::listen() instead.")]]
   notification_receiver(notification_receiver const &) = delete;
   /// Register the receiver with a connection.
+  [[deprecated("Use pqxx::connection::listen() instead.")]]
   notification_receiver &operator=(notification_receiver const &) = delete;
   /// Deregister the receiver.
   virtual ~notification_receiver();

src/connection.cxx

@@ -608,16 +608,20 @@ int pqxx::connection::get_notifs()
 
   // Even if somehow we receive notifications during our transaction, don't
   // deliver them.
-  if (m_trans)
+  if (m_trans != nullptr)
     PQXX_UNLIKELY
   return 0;
 
   int notifs = 0;
+
+  // Old mechanism.  This is going away.
   for (auto N{get_notif(m_conn)}; N.get(); N = get_notif(m_conn))
   {
     notifs++;
 
-    auto const Hit{m_receivers.equal_range(std::string{N->relname})};
+    std::string const name{N->relname};
+
+    auto const Hit{m_receivers.equal_range(name)};
     if (Hit.second != Hit.first)
     {
       std::string const payload{N->extra};
@@ -649,8 +653,16 @@ int pqxx::connection::get_notifs()
         }
     }
 
+    auto const handler{m_notification_handlers.find(N->relname)};
+    if (handler != std::end(m_notification_handlers))
+    {
+      ++notifs;
+      (handler->second)(name, N->be_pid, N->extra);
+    }
+
     N.reset();
   }
+
   return notifs;
 }