Allow TerraSync to be inited early.

Add explicit subsystem state tracking so we can safely init()
terrasync very early during startup, and hence overlap lengthy operations
(Shared Models sync and initial NavCache build)

simgear/scene/tsync/terrasync.cxx

@@ -152,11 +152,17 @@ public:
 class SyncSlot
 {
 public:
+    SyncSlot() :
+        isNewDirectory(false),
+        busy(false)
+    {}
+    
     WaitingSyncItem currentItem;
     bool isNewDirectory;
     std::queue<WaitingSyncItem> queue;
     std::auto_ptr<SVNRepository> repository;
     SGTimeStamp stamp;
+    bool busy; ///< is the slot working or idle
 };
 
 static const int SYNC_SLOT_TILES = 0; ///< Terrain and Objects sync
@@ -499,10 +505,12 @@ void SGTerraSync::SvnThread::syncPathExternal(const WaitingSyncItem& next)
         }
     } catch (sg_exception& e) {
         fail(next);
+        _busy = false;
         return;
     }
     
     updated(next, isNewDirectory);
+    _busy = false;
 }
 
 void SGTerraSync::SvnThread::updateSyncSlot(SyncSlot &slot)
@@ -526,6 +534,7 @@ void SGTerraSync::SvnThread::updateSyncSlot(SyncSlot &slot)
         }
 
         // whatever happened, we're done with this repository instance
+        slot.busy = false;
         slot.repository.reset();
     }
     
@@ -552,6 +561,7 @@ void SGTerraSync::SvnThread::updateSyncSlot(SyncSlot &slot)
         slot.repository->update();
         
         slot.stamp.stamp();
+        slot.busy = true;
         SG_LOG(SG_IO, SG_DEBUG, "sync of " << slot.repository->baseUrl() << " started");
     }
 }
@@ -577,10 +587,14 @@ void SGTerraSync::SvnThread::runInternal()
             _syncSlots[slot].queue.push(next);
         }
        
+        bool anySlotBusy = false;
         // update each sync slot in turn
         for (unsigned int slot=0; slot < NUM_SYNC_SLOTS; ++slot) {
             updateSyncSlot(_syncSlots[slot]);
+            anySlotBusy |= _syncSlots[slot].busy;
         }
+        
+        _busy = anySlotBusy;
     } // of thread running loop
 }
 
@@ -608,7 +622,6 @@ void SGTerraSync::SvnThread::fail(const WaitingSyncItem& failedItem)
     _consecutive_errors++;
     _fail_count++;
     _completedTiles[ failedItem._dir ] = now + UpdateInterval::FailedAttempt;
-    _busy = false;
 }
 
 void SGTerraSync::SvnThread::updated(const WaitingSyncItem& item, bool isNewDirectory)
@@ -632,7 +645,6 @@ void SGTerraSync::SvnThread::updated(const WaitingSyncItem& item, bool isNewDire
     
     _completedTiles[ item._dir ] = now + UpdateInterval::SuccessfulAttempt;
     writeCompletedTilesPersistentCache();
-    _busy = false;
 }
 
 void SGTerraSync::SvnThread::initCompletedTilesPersistentCache()
@@ -689,6 +701,8 @@ SGTerraSync::SGTerraSync(SGPropertyNode_ptr root) :
     last_lat(NOWHERE),
     last_lon(NOWHERE),
     _terraRoot(root->getNode("/sim/terrasync",true)),
+    _bound(false),
+    _inited(false),
     _refreshCb(NULL),
     _userCbData(NULL)
 {
@@ -710,6 +724,11 @@ SGTerraSync::~SGTerraSync()
 
 void SGTerraSync::init()
 {
+    if (_inited) {
+        return;
+    }
+    
+    _inited = true;
     _refreshDisplay = _terraRoot->getNode("refresh-display",true);
     _terraRoot->setBoolValue("built-in-svn-available",svn_built_in_available);
     reinit();
@@ -720,8 +739,10 @@ void SGTerraSync::reinit()
     // do not reinit when enabled and we're already up and running
     if ((_terraRoot->getBoolValue("enabled",false))&&
          (_svnThread->_active && _svnThread->_running))
+    {
         return;
-
+    }
+    
     _svnThread->stop();
 
     if (_terraRoot->getBoolValue("enabled",false))
@@ -756,6 +777,11 @@ void SGTerraSync::reinit()
 
 void SGTerraSync::bind()
 {
+    if (_bound) {
+        return;
+    }
+    
+    _bound = true;
     _tiedProperties.Tie( _terraRoot->getNode("busy", true), (bool*) &_svnThread->_busy );
     _tiedProperties.Tie( _terraRoot->getNode("active", true), (bool*) &_svnThread->_active );
     _tiedProperties.Tie( _terraRoot->getNode("update-count", true), (int*) &_svnThread->_success_count );
@@ -780,6 +806,8 @@ void SGTerraSync::unbind()
 {
     _svnThread->stop();
     _tiedProperties.Untie();
+    _bound = false;
+    _inited = false;
 }
 
 void SGTerraSync::update(double)

simgear/scene/tsync/terrasync.hxx

@@ -42,7 +42,8 @@ public:
 
     SGTerraSync(SGPropertyNode_ptr root);
     virtual ~SGTerraSync();
-    virtual void init();
+    
+    virtual void init();    
     virtual void reinit();
     virtual void bind();
     virtual void unbind();
@@ -76,6 +77,12 @@ private:
     SGPropertyNode_ptr _stalledNode;
     SGPropertyNode_ptr _cacheHits;
     
+    // we manually bind+init TerraSync during early startup
+    // to get better overlap of slow operations (Shared Models sync
+    // and nav-cache rebuild). As a result we need to track the bind/init
+    // state explicitly to avoid duplicate calls.
+    bool _bound, _inited;
+    
     SGTerraSyncCallback _refreshCb;
     void* _userCbData;
     simgear::TiedPropertyList _tiedProperties;