[traffic] Use enabled state instead of Start()

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

map/framework.cpp

@@ -376,7 +376,6 @@ Framework::Framework(FrameworkParams const & params, bool loadMaps)
 
   m_trafficManager.SetCurrentDataVersion(m_storage.GetCurrentDataVersion());
   m_trafficManager.SetSimplifiedColorScheme(LoadTrafficSimplifiedColors());
-  m_trafficManager.SetEnabled(LoadTrafficEnabled());
 
   m_isolinesManager.SetEnabled(LoadIsolinesEnabled());
 
@@ -390,7 +389,7 @@ Framework::Framework(FrameworkParams const & params, bool loadMaps)
   if (loadMaps)
     LoadMapsSync();
 
-  m_trafficManager.Start();
+  m_trafficManager.SetEnabled(LoadTrafficEnabled());
 }
 
 Framework::~Framework()

map/traffic_manager.cpp

@@ -72,7 +72,6 @@ TrafficManager::TrafficManager(DataSource & dataSource, CountryInfoGetterFn coun
   , m_maxCacheSizeBytes(maxCacheSizeBytes)
 #endif
   , m_isRunning(true)
-  , m_isStarted(false)
   , m_isPaused(false)
   , m_thread(&TrafficManager::ThreadRoutine, this)
 {
@@ -117,7 +116,10 @@ void TrafficManager::SetEnabled(bool enabled)
     std::lock_guard<std::mutex> lock(m_mutex);
     if (enabled == IsEnabled())
        return;
-    Clear();
+    if (enabled && !m_traffDecoder)
+      // deferred decoder initialization (requires maps to be loaded)
+      m_traffDecoder = make_unique<traffxml::DefaultTraffDecoder>(m_dataSource, m_countryInfoGetterFn,
+                                                                  m_countryParentNameGetterFn, m_messageCache);
     ChangeState(enabled ? TrafficState::Enabled : TrafficState::Disabled);
   }
 
@@ -129,13 +131,6 @@ void TrafficManager::SetEnabled(bool enabled)
     m_observer.OnTrafficInfoClear();
 }
 
-void TrafficManager::Start()
-{
-  m_traffDecoder = make_unique<traffxml::DefaultTraffDecoder>(m_dataSource, m_countryInfoGetterFn,
-                                                              m_countryParentNameGetterFn, m_messageCache);
-  m_isStarted = true;
-}
-
 void TrafficManager::Clear()
 {
 // TODO no longer needed
@@ -561,7 +556,7 @@ bool TrafficManager::WaitForRequest()
   if (!m_isRunning)
     return false;
 
-  if (m_isStarted)
+  if (IsEnabled())
   {
     // if we have feeds in the queue, return immediately
     if (!m_feedQueue.empty())
@@ -592,7 +587,7 @@ bool TrafficManager::WaitForRequest()
     return false;
 
   // this works as long as wait timeout is at least equal to the poll interval
-  if (m_isStarted)
+  if (IsEnabled())
     m_isPollNeeded |= timeout;
 
   LOG(LINFO, ("timeout:", timeout, "active MWMs changed:", m_activeMwmsChanged));

map/traffic_manager.hpp

@@ -98,11 +98,26 @@ public:
   /**
    * @brief Enables or disables the traffic manager.
    *
-   * This sets the internal state and notifies the drape engine. Enabling the traffic manager will
+   * This sets the internal state and notifies the drape engine.
-   * invalidate its data, disabling it will notify the observer that traffic data has been cleared.
+   *
+   * Upon creation, the traffic manager is disabled and will not poll any sources or process any
+   * feeds until enabled. Feeds received through `Push()` will be added to the queue before the
+   * traffic manager is started, but will not be processed any further until the traffic manager is
+   * started.
+   *
+   * MWMs must be loaded before first enabling the traffic manager.
    *
    * Calling this function with `enabled` identical to the current state is a no-op.
    *
+   * @todo Currently, all MWMs must be loaded before calling `SetEnabled()`, as MWMs loaded after
+   * that will not get picked up. We need to extend `TrafficManager` to react to MWMs being added
+   * (and removed) – note that this affects the `DataSource`, not the set of active MWMs.
+   *
+   * @todo Enabling the traffic manager will invalidate its data, disabling it will notify the
+   * observer that traffic data has been cleared. This is old logic, to be reviewed/removed.
+   *
+   * @todo State/pause/resume logic is not fully implemented ATM and needs to be revisited.
+   *
    * @param enabled True to enable, false to disable
    */
   void SetEnabled(bool enabled);
@@ -117,20 +132,6 @@ public:
   /**
    * @brief Starts the traffic manager.
    *
-   * After creation, the traffic manager will not poll any sources or process any feeds until it is
-   * started. Feeds received through `Push()` will be added to the queue before the traffic manager
-   * is started, but will not be processed any further until the traffic manager is started.
-   *
-   * MWMs must be loaded before starting the traffic manager.
-   *
-   * @todo Currently, all MWMs must be loaded before calling `Start()`, as MWMs loaded after that
-   * will not get picked up. We need to extend `TrafficManager` to react to MWMs being added (and
-   * removed) – note that this affects the `DataSource`, not the set of active MWMs.
-   *
-   * @todo Start is currently not integrated with state or pause/resume logic (all of which might
-   * not be fully implemented ATM). If the traffic manager is not started, no message processing
-   * (other than filling the queue and deduplication) will take place, regardless of state. Starting
-   * the traffic manager will not change the state it reports.
    */
   void Start();
 
@@ -145,7 +146,8 @@ public:
    * This happens when a new MWM file is downloaded, the traffic manager is enabled after being
    * disabled or resumed after being paused.
    *
-   * @todo this goes for the old MWM arch, see if this makes sense for TraFF.
+   * @todo this goes for the old MWM arch. For TraFF we need to refresh the MWM set for the decoder
+   * and possibly decode locations again (MWMs might have changed, or new ones added).
    */
   void Invalidate();
 
@@ -530,11 +532,6 @@ private:
   // which allows a client to make conditional requests.
   std::map<MwmSet::MwmId, std::string> m_trafficETags;
 
-  /**
-   * Whether the traffic manager should begin receiving information.
-   */
-  std::atomic<bool> m_isStarted;
-
   std::atomic<bool> m_isPaused;
 
   /**