Broadcast Time Server Detection (#521)

* Add method for determining if a timer server has been discovered.

* Add test for time server discovery.

* Make methods public.

* Mask "server" detection for date events only.

src/openlcb/BroadcastTime.hxx

@@ -358,6 +358,10 @@ public:
         return &tm_;
     }
 
+    /// Has a time server been detected?
+    /// @return true if a time server has been detected, else false
+    virtual bool is_server_detected() = 0;
+
 protected:
     class SetFlow : public StateFlowBase
     {

src/openlcb/BroadcastTimeClient.cxxtest

@@ -250,6 +250,8 @@ TEST_F(BroadcastTimeClientTest, Create)
     EXPECT_EQ(client2_->time(), 0);
     EXPECT_EQ(client2_->day_of_week(), BroadcastTimeDefs::THURSDAY);
     EXPECT_EQ(client2_->day_of_year(), 0);
+    EXPECT_FALSE(client1_->is_server_detected());
+    EXPECT_FALSE(client2_->is_server_detected());
 };
 
 TEST_F(BroadcastTimeClientTest, Start)
@@ -265,6 +267,7 @@ TEST_F(BroadcastTimeClientTest, Start)
     sync(client1_, 500);
     wait();
 
+    EXPECT_TRUE(client1_->is_server_detected());
 
     // check the time, we give it a finite range just in case of some OS jitter
     EXPECT_TRUE(IsBetweenInclusive(client1_->time(), 60, 62));

src/openlcb/BroadcastTimeClient.hxx

@@ -62,6 +62,7 @@ public:
         , rolloverPending_(false)
         , rolloverPendingDate_(false)
         , rolloverPendingYear_(false)
+        , serverDetected_(false)
     {
         EventRegistry::instance()->register_handler(
             EventRegistryEntry(this, eventBase_), 16);
@@ -73,6 +74,13 @@ public:
         EventRegistry::instance()->unregister_handler(this);
     }
 
+    /// Has a time server been detected?
+    /// @return true if a time server has been detected, else false
+    bool is_server_detected() override
+    {
+        return serverDetected_;
+    }
+
     /// Handle requested identification message.
     /// @param entry registry entry for the event range
     /// @param event information about the incoming message
@@ -176,6 +184,13 @@ public:
 
         if (event->state == EventState::VALID)
         {
+            // Look for a Report Date Event ID.
+            if ((event->event & 0x000000000000F000ULL) == 0x2000ULL)
+            {
+                // We can only get here if there is a time server detected.
+                serverDetected_ = true;
+            }
+
             // We only care about valid event state.
             // Producer identified only happens when a clock synchronization
             // is taking place.  This voids previous date rollover events.
@@ -422,6 +437,7 @@ private:
     uint16_t rolloverPending_  : 1; ///< a day rollover is about to occur
     uint16_t rolloverPendingDate_ : 1; ///< a day rollover is about to occur
     uint16_t rolloverPendingYear_ : 1; ///< a day rollover is about to occur
+    uint16_t serverDetected_      : 1; ///< has a time server been detected
 
 
     DISALLOW_COPY_AND_ASSIGN(BroadcastTimeClient);

src/openlcb/BroadcastTimeServer.cxxtest

@@ -111,6 +111,7 @@ TEST_F(BroadcastTimeServerTest, Create)
     EXPECT_EQ(server_->time(), 0);
     EXPECT_EQ(server_->day_of_week(), BroadcastTimeDefs::THURSDAY);
     EXPECT_EQ(server_->day_of_year(), 0);
+    EXPECT_TRUE(server_->is_server_detected());
 };
 
 TEST_F(BroadcastTimeServerTest, Time)

src/openlcb/BroadcastTimeServer.hxx

@@ -59,6 +59,13 @@ public:
     /// Destructor.
     ~BroadcastTimeServer();
 
+    /// Has a time server been detected?
+    /// @return true if a time server has been detected, else false
+    bool is_server_detected() override
+    {
+        return true;
+    }
+
 #if defined(GTEST)
     void shutdown();