[openlr] Initialize OpenLR decoder with a single DataSource

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

map/traffic_manager.cpp

@@ -60,6 +60,7 @@ TrafficManager::TrafficManager(DataSource & dataSource,
                                traffic::TrafficObserver & observer)
   : m_dataSource(dataSource)
   , m_countryParentNameGetterFn(countryParentNameGetter)
+  , m_openLrDecoder(m_dataSource, countryParentNameGetter)
   , m_getMwmsByRectFn(getMwmsByRectFn)
   , m_observer(observer)
   , m_currentDataVersion(0)
@@ -403,8 +404,7 @@ void TrafficManager::InitializeDataSources(std::vector<FrozenDataSource> & dataS
  * If we batch-decode segments, we need to fix the [partner] segment IDs in the segment and path
  * structures to accept a TraFF message ID (string) rather than an integer.
  */
-void TrafficManager::DecodeMessage(openlr::OpenLRDecoder & decoder,
-                                   traffxml::TraffMessage & message, std::map<std::string,
+void TrafficManager::DecodeMessage(traffxml::TraffMessage & message, std::map<std::string,
                                    traffic::TrafficInfo::Coloring> & trafficCache)
 {
   if (message.m_location)
@@ -439,7 +439,7 @@ void TrafficManager::DecodeMessage(openlr::OpenLRDecoder & decoder,
     // Decode the location into a path on the map.
     // One path per segment
     std::vector<openlr::DecodedPath> paths(segments.size());
-    decoder.DecodeV3(segments, kNumDecoderThreads, paths);
+    m_openLrDecoder.DecodeV3(segments, kNumDecoderThreads, paths);
 
     for (size_t i = 0; i < paths.size(); i++)
     {
@@ -547,22 +547,6 @@ void TrafficManager::ThreadRoutine()
     UpdateMessageCache(m_messageCache);
     LOG(LINFO, (m_messageCache.size(), "message(s) in cache"));
 
-    // initialize the decoder
-    /*
-     * Access to `DataSource` is not thread-safe. The main app, which works with
-     * `EditableDataSource` (as the map can be edited), wraps map operations into a
-     * `FeaturesLoaderGuard`. The OpenLR decoder expects one `FrozenDataSource` (a read-only
-     * subclass) per worker thread – which works as long as the map is not modified.
-     * Edits are not relevant to the OpenLR decoder. However, if the edits modify MWM files (rather
-     * than being stored separately), this might confuse the `FrozenDataSource`. In this case, we
-     * would need to rewrite the OpenLR decoder to work with a `FeaturesLoaderGuard` (which is
-     * probably the more elegant way to do this anyway).
-     */
-    std::vector<FrozenDataSource> dataSources(kNumDecoderThreads);
-    // TODO test with data source from framework
-    InitializeDataSources(dataSources);
-    openlr::OpenLRDecoder decoder(dataSources, m_countryParentNameGetterFn);
-
     /*
      * Map between country names and their colorings.
      * TODO use MwmId as map keys:
@@ -577,7 +561,7 @@ void TrafficManager::ThreadRoutine()
     for (auto [id, message] : m_messageCache)
     {
       LOG(LINFO, (" ", id, ":", message));
-      DecodeMessage(decoder, message, allMwmColoring);
+      DecodeMessage(message, allMwmColoring);
     }
 
     // set new coloring for MWMs

map/traffic_manager.hpp

@@ -259,7 +259,7 @@ private:
    * @param message The message to decode.
    * @param trafficCache The cache in which all decoded paths with their speed groups will be stored.
    */
-  void DecodeMessage(openlr::OpenLRDecoder &decoder, traffxml::TraffMessage & message,
+  void DecodeMessage(traffxml::TraffMessage & message,
                      std::map<std::string, traffic::TrafficInfo::Coloring> & trafficCache);
 
   /**
@@ -514,6 +514,13 @@ private:
    * Keys are message IDs, values are messages.
    */
   std::map<std::string, traffxml::TraffMessage> m_messageCache;
+
+  /**
+   * @brief The OpenLR decoder instance.
+   *
+   * Used to decode TraFF locations into road segments on the map.
+   */
+  openlr::OpenLRDecoder m_openLrDecoder;
 };
 
 extern std::string DebugPrint(TrafficManager::TrafficState state);

openlr/openlr_decoder.cpp

@@ -437,9 +437,9 @@ bool OpenLRDecoder::SegmentsFilter::Matches(LinearSegment const & segment) const
 }
 
 // OpenLRDecoder -----------------------------------------------------------------------------
-OpenLRDecoder::OpenLRDecoder(vector<FrozenDataSource> & dataSources,
+OpenLRDecoder::OpenLRDecoder(DataSource & dataSource,
                              CountryParentNameGetter const & countryParentNameGetter)
-  : m_dataSources(dataSources), m_countryParentNameGetter(countryParentNameGetter)
+  : m_dataSource(dataSource), m_countryParentNameGetter(countryParentNameGetter)
 {
 }
 
@@ -490,9 +490,9 @@ void OpenLRDecoder::Decode(vector<LinearSegment> const & segments,
   vector<Stats> stats(numThreads);
   vector<thread> workers;
   for (size_t i = 1; i < numThreads; ++i)
-    workers.emplace_back(worker, i, ref(m_dataSources[i]), ref(stats[i]));
+    workers.emplace_back(worker, i, ref(m_dataSource), ref(stats[i]));
 
-  worker(0 /* threadNum */, m_dataSources[0], stats[0]);
+  worker(0 /* threadNum */, m_dataSource, stats[0]);
   for (auto & worker : workers)
     worker.join();
 

openlr/openlr_decoder.hpp

@@ -40,7 +40,7 @@ public:
     bool const m_multipointsOnly;
   };
 
-  OpenLRDecoder(std::vector<FrozenDataSource> & dataSources,
+  OpenLRDecoder(DataSource & dataSource,
                 CountryParentNameGetter const & countryParentNameGetter);
 
   /**
@@ -62,7 +62,7 @@ private:
   void Decode(std::vector<LinearSegment> const & segments, uint32_t const numThreads,
               std::vector<DecodedPath> & paths);
 
-  std::vector<FrozenDataSource> & m_dataSources;
+  DataSource & m_dataSource;
   CountryParentNameGetter m_countryParentNameGetter;
 };
 }  // namespace openlr