[traffxml] Purge expired messages

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

map/traffic_manager.cpp

@@ -22,6 +22,12 @@ namespace
  * Poll interval for traffic data
  */
 auto constexpr kUpdateInterval = minutes(1);
+
+/**
+ * Purge interval for expired traffic messages
+ */
+auto constexpr kPurgeInterval = minutes(1);
+
 auto constexpr kOutdatedDataTimeout = minutes(5) + kUpdateInterval;
 auto constexpr kNetworkErrorTimeout = minutes(20);
 
@@ -404,6 +410,21 @@ void TrafficManager::Push(traffxml::TraffFeed feed)
   m_condition.notify_one();
 }
 
+void TrafficManager::PurgeExpiredMessages()
+{
+  std::lock_guard<std::mutex> lock(m_mutex);
+  LOG(LINFO, ("before:", m_messageCache.size(), "message(s)"));
+  traffxml::IsoTime now = traffxml::IsoTime::Now();
+  for (auto it = m_messageCache.begin(); it != m_messageCache.end(); )
+  {
+    if (it->second.IsExpired(now))
+      it = m_messageCache.erase(it);
+    else
+      ++it;
+  }
+  LOG(LINFO, ("after:", m_messageCache.size(), "message(s)"));
+}
+
 void TrafficManager::ConsolidateFeedQueue()
 {
   std::lock_guard<std::mutex> lock(m_mutex);
@@ -504,7 +525,8 @@ void TrafficManager::DecodeFirstMessage()
 
 void TrafficManager::ThreadRoutine()
 {
-  // initially, treat drape and observer as having just been updated
+  // initially, treat last purge and drape/observer update as having just happened
+  auto lastPurged = steady_clock::now();
   m_lastDrapeUpdate = steady_clock::now();
   m_lastObserverUpdate = steady_clock::now();
 
@@ -513,11 +535,15 @@ void TrafficManager::ThreadRoutine()
     if (!IsEnabled())
       continue;
 
-    // TODO clean out expired messages
-
     if (!IsTestMode())
     {
-      LOG(LINFO, ("start loop, active MWMs changed:", m_activeMwmsChanged, ", poll needed:", m_isPollNeeded));
+      if (steady_clock::now() - lastPurged >= kPurgeInterval)
+      {
+        lastPurged == steady_clock::now();
+        PurgeExpiredMessages();
+      }
+
+      LOG(LINFO, ("active MWMs changed:", m_activeMwmsChanged, ", poll needed:", m_isPollNeeded));
 
       // this is a no-op if active MWMs have not changed
       if (!SetSubscriptionArea())

map/traffic_manager.hpp

@@ -198,7 +198,8 @@ public:
    * will log a warning but otherwise do nothing.
    *
    * In test mode, the traffic manager will not subscribe to sources or poll them automatically.
-   * It will still receive and process push feeds.
+   * Expired messages will not get purged automatically, but `PurgeExpiredMessages()` can be called
+   * to purge expired messages once. The traffic manager will still receive and process push feeds.
    *
    * Future versions may introduce further behavior changes.
    */
@@ -215,6 +216,13 @@ public:
    */
   void Push(traffxml::TraffFeed feed);
 
+  /**
+   * @brief Purges expired messages from the cache.
+   *
+   * This method is safe to call from any thread.
+   */
+  void PurgeExpiredMessages();
+
   /**
    * @brief Clears the entire traffic cache.
    *

traffxml/traff_assessment_tool/mainwindow.cpp

@@ -265,6 +265,7 @@ MainWindow::MainWindow(Framework & framework)
   menuBar()->addMenu(fileMenu);
 
   fileMenu->addAction("Open sample", QKeySequence("Ctrl+O"), this, &MainWindow::OnOpenTrafficSample);
+  fileMenu->addAction("Purge expired messages", QKeySequence("Ctrl+P"), this, &MainWindow::OnPurgeExpiredMessages);
   fileMenu->addAction("Clear TraFF cache", QKeySequence("Ctrl+D"), this, &MainWindow::OnClearCache);
 
   m_closeTrafficSampleAction = fileMenu->addAction("Close sample", QKeySequence("Ctrl+W"), this, &MainWindow::OnCloseTrafficSample);
@@ -408,6 +409,11 @@ void MainWindow::OnOpenTrafficSample()
 #endif
 }
 
+void MainWindow::OnPurgeExpiredMessages()
+{
+  m_framework.GetTrafficManager().PurgeExpiredMessages();
+}
+
 void MainWindow::OnClearCache()
 {
   m_framework.GetTrafficManager().Clear();

traffxml/traff_assessment_tool/mainwindow.hpp

@@ -41,6 +41,11 @@ private:
    */
   void OnOpenTrafficSample();
 
+  /**
+   * Called when the user requests to purge expired messages.
+   */
+  void OnPurgeExpiredMessages();
+
   /**
    * Called when the user requests to clear the cache.
    */

traffxml/traff_model.cpp

@@ -195,6 +195,21 @@ bool operator==(TraffLocation const & lhs, TraffLocation const & rhs)
       && (lhs.m_to == rhs.m_to);
 }
 
+IsoTime TraffMessage::GetEffectiveExpirationTime()
+{
+  IsoTime result = m_expirationTime;
+  if (m_startTime && m_startTime.value() > result)
+    result = m_startTime.value();
+  if (m_endTime && m_endTime.value() > result)
+    result = m_endTime.value();
+  return result;
+}
+
+bool TraffMessage::IsExpired(IsoTime now)
+{
+  return GetEffectiveExpirationTime() < now;
+}
+
 std::optional<TrafficImpact> TraffMessage::GetTrafficImpact()
 {
   // no events, no impact

traffxml/traff_model.hpp

@@ -359,6 +359,27 @@ using MultiMwmColoring = std::map<MwmSet::MwmId, std::map<traffic::TrafficInfo::
 
 struct TraffMessage
 {
+  /**
+   * @brief Gets the time after which this message effectively expires.
+   *
+   * The effective expiration time is the latest of `m_expirationTime`, `m_startTime` and
+   * `m_endTime`. `nullopt` values are ignored.
+   *
+   * @return The effective expiration time for the message.
+   */
+  IsoTime GetEffectiveExpirationTime();
+
+  /**
+   * @brief Whether the message has expired.
+   *
+   * A message is considered to have expired if its effective expiration time (as returned by
+   * `GetEffectiveExpirationTime()` refers to a point in time before `now`.
+   *
+   * @param now The reference time to compare to (usually current time)
+   * @return True if the message has expired, false if not.
+   */
+  bool IsExpired(IsoTime now);
+
   /**
    * @brief Retrieves the traffic impact of all events.
    *