[traffic] Refactoring

Signed-off-by: mvglasow <michael -at- vonglasow.com>

map/traffic_manager.cpp

@@ -322,7 +322,12 @@ void TrafficManager::OnChangeRoutingSessionState(routing::SessionState previous,
     {
       m_activeMwmsChanged = true;
       std::swap(mwms, m_activeRoutingMwms);
-      RequestTrafficSubscription();
+
+      if ((m_activeDrapeMwms.empty() && m_activePositionMwms.empty() && m_activeRoutingMwms.empty())
+          || !IsEnabled() || IsInvalidState() || m_isPaused)
+        return;
+
+      m_condition.notify_one();
     }
   }
 }
@@ -409,7 +414,12 @@ void TrafficManager::UpdateActiveMwms(m2::RectD const & rect,
       if (mwm.IsAlive())
         activeMwms.insert(mwm);
     }
-    RequestTrafficSubscription();
+
+    if ((m_activeDrapeMwms.empty() && m_activePositionMwms.empty() && m_activeRoutingMwms.empty())
+        || !IsEnabled() || IsInvalidState() || m_isPaused)
+      return;
+
+    m_condition.notify_one();
   }
 }
 
@@ -839,6 +849,8 @@ bool TrafficManager::WaitForRequest()
   return true;
 }
 
+// TODO no longer needed
+#ifdef traffic_dead_code
 void TrafficManager::RequestTrafficSubscription()
 {
   if ((m_activeDrapeMwms.empty() && m_activePositionMwms.empty() && m_activeRoutingMwms.empty())
@@ -862,8 +874,6 @@ void TrafficManager::RequestTrafficSubscription()
 #endif
 }
 
-// TODO no longer needed
-#ifdef traffic_dead_code
 void TrafficManager::OnTrafficRequestFailed(traffic::TrafficInfo && info)
 {
   std::lock_guard<std::mutex> lock(m_mutex);

map/traffic_manager.hpp

@@ -498,6 +498,8 @@ private:
 
   // This is a group of methods that haven't their own synchronization inside.
 
+// TODO no longer needed
+#ifdef traffic_dead_code
   /**
    * @brief Requests a refresh of traffic subscriptions to match all currently active MWMs.
    *
@@ -511,8 +513,6 @@ private:
    */
   void RequestTrafficSubscription();
 
-// TODO no longer needed
-#ifdef traffic_dead_code
   /**
    * @brief Removes traffic data for one specific MWM from the cache.
    *
@@ -642,24 +642,20 @@ private:
    *
    * Routing MWMs are stored as a set.
    *
-   * The other groups arestored twice: as a set and as a vector. The set always holds the MWMs which
+   * The other groups are stored twice: as a set and as a vector. The set always holds the MWMs which
    * were last seen in use. Both get updated together when active MWMs are added or removed.
-   * However, the vector is used as a reference to detect changes. It may get cleared when the set
-   * is not, which is used to invalidate the set without destroying its contents.
+   * However, the vector is used as a reference to detect changes. Clear() clears the vector but not
+   * the set, invalidating the set without destroying its contents.
    *
    * Methods which use only the set:
    *
    * * RequestTrafficSubscription(), exits if empty, otherwise cycles through the set.
-   * * OnTrafficRequestFailed(), determines if an MWM is still active and the request should be retried.
-   * * UniteActiveMwms(), build the list of active MWMs (used by RequestTrafficSubscription() or to shrink the cache).
-   * * UpdateState(), cycles through the set to determine the state of traffic requests (renderer only).
+   * * UniteActiveMwms(), build the list of active MWMs (used by RequestTrafficSubscription()).
    *
    * Methods which use both, but in a different way:
    *
-   * * (dead code) ClearCache(), removes the requested MWM from the set but clears the vector completely.
-   * * UpdateActiveMwms(), uses the vector to detect changes (not for routing MWMs). If so, it updates both vector and set.
-   *
-   * Clear() clears both the set and the vector. (Clearing the set is currently disabled as it breaks ForEachActiveMwm.)
+   * * UpdateActiveMwms(), uses the vector to detect changes (not for routing MWMs). If so, it
+   *   updates both vector and set, but adds MWMs to the set only if they are alive.
    */
   std::vector<MwmSet::MwmId> m_lastDrapeMwmsByRect;
   std::set<MwmSet::MwmId> m_activeDrapeMwms;
@@ -667,6 +663,11 @@ private:
   std::set<MwmSet::MwmId> m_activePositionMwms;
   std::set<MwmSet::MwmId> m_activeRoutingMwms;
 
+  /**
+   * @brief Whether active MWMs have changed since the last request.
+   */
+  bool m_activeMwmsChanged = false;
+
 // TODO no longer needed
 #ifdef traffic_dead_code
   // The ETag or entity tag is part of HTTP, the protocol for the World Wide Web.
@@ -726,11 +727,6 @@ private:
    */
   std::chrono::time_point<std::chrono::steady_clock> m_lastStorageUpdate;
 
-  /**
-   * @brief Whether active MWMs have changed since the last request.
-   */
-  bool m_activeMwmsChanged = false;
-
   /**
    * @brief Whether a poll operation is needed.
    *