1 files changed, 19 insertions, 2 deletions
diff --git a/src/mbgl/map/tile_data.hpp b/src/mbgl/map/tile_data.hpp
index 57f7c30ff3..7f16e7c413 100644
--- a/src/mbgl/map/tile_data.hpp
+++ b/src/mbgl/map/tile_data.hpp
@@ -49,10 +49,24 @@ public:
     void cancel();
     const std::string toString() const;
 
-    inline bool ready() const {
+    inline bool isReady() const {
         return isReadyState(state);
     }
 
+    // Returns true if the TileData is in a final state and we cannot
+    // make changes to it anymore.
+    inline bool isImmutable() const {
+        return state == State::parsed || state == State::obsolete;
+    }
+
+    // We let subclasses override setState() so they
+    // can intercept the state change and react accordingly.
+    virtual void setState(const State& state);
+
+    inline State getState() const {
+        return state;
+    }
+
     void endParsing();
 
     // Override this in the child class.
@@ -61,7 +75,6 @@ public:
 
     const TileID id;
     const std::string name;
-    std::atomic<State> state;
     std::atomic_flag parsing = ATOMIC_FLAG_INIT;
 
 protected:
@@ -81,6 +94,10 @@ protected:
 
     std::unique_ptr<WorkRequest> workRequest;
 
+private:
+    std::atomic<State> state;
+
+protected:
     // Contains the tile ID string for painting debug information.
     DebugFontBuffer debugFontBuffer;