[core] make sure that 304 Not Modified requests correctly update tile state

4 files changed, 16 insertions, 12 deletions

diff --git a/src/mbgl/tile/raster_tile.cpp b/src/mbgl/tile/raster_tile.cpp
index 5906b0f6a0..be78a9988b 100644
--- a/src/mbgl/tile/raster_tile.cpp
+++ b/src/mbgl/tile/raster_tile.cpp
@@ -36,17 +36,19 @@ void RasterTile::setError(std::exception_ptr err, const bool complete) {
 }
 
 // Called when new data is available for this tile. It can be called even if there is already data
-// in this tile.
-void RasterTile::setData(std::shared_ptr<const std::string> data,
-                         const optional<Timestamp> modified_,
-                         const optional<Timestamp> expires_,
+// in this tile. When the existing data should remain the same, the optional data field is empty.
+void RasterTile::setData(optional<std::shared_ptr<const std::string>> data,
+                         optional<Timestamp> modified_,
+                         optional<Timestamp> expires_,
                          const bool complete) {
     (void)complete;
     modified = modified_;
     expires = expires_;
 
-    ++correlationID;
-    worker.invoke(&RasterTileWorker::parse, data, correlationID);
+    if (data) {
+        ++correlationID;
+        worker.invoke(&RasterTileWorker::parse, *data, correlationID);
+    }
 }
 
 // Invoked once the worker thread finished parsing the image.
diff --git a/src/mbgl/tile/raster_tile.hpp b/src/mbgl/tile/raster_tile.hpp
index b92637b711..f5f6ea944c 100644
--- a/src/mbgl/tile/raster_tile.hpp
+++ b/src/mbgl/tile/raster_tile.hpp
@@ -25,7 +25,7 @@ public:
     void setNecessity(Necessity) final;
 
     void setError(std::exception_ptr, bool complete);
-    void setData(std::shared_ptr<const std::string> data,
+    void setData(optional<std::shared_ptr<const std::string>> data,
                  optional<Timestamp> modified_,
                  optional<Timestamp> expires_,
                  bool complete);
diff --git a/src/mbgl/tile/vector_tile.cpp b/src/mbgl/tile/vector_tile.cpp
index f03f836851..e22ccf0d54 100644
--- a/src/mbgl/tile/vector_tile.cpp
+++ b/src/mbgl/tile/vector_tile.cpp
@@ -21,7 +21,7 @@ void VectorTile::setError(std::exception_ptr err, const bool complete) {
     GeometryTile::setError(err);
 }
 
-void VectorTile::setData(std::shared_ptr<const std::string> data_,
+void VectorTile::setData(optional<std::shared_ptr<const std::string>> data,
                          optional<Timestamp> modified_,
                          optional<Timestamp> expires_,
                          const bool complete) {
@@ -29,7 +29,9 @@ void VectorTile::setData(std::shared_ptr<const std::string> data_,
     modified = modified_;
     expires = expires_;
 
-    GeometryTile::setData(data_ ? std::make_unique<VectorTileData>(data_) : nullptr);
+    if (data) {
+        GeometryTile::setData(*data ? std::make_unique<VectorTileData>(*data) : nullptr);
+    }
 }
 
 } // namespace mbgl
diff --git a/src/mbgl/tile/vector_tile.hpp b/src/mbgl/tile/vector_tile.hpp
index c34fa4d763..c7caa0a1f6 100644
--- a/src/mbgl/tile/vector_tile.hpp
+++ b/src/mbgl/tile/vector_tile.hpp
@@ -18,9 +18,9 @@ public:
     void setNecessity(Necessity) final;
 
     void setError(std::exception_ptr, bool complete);
-    void setData(std::shared_ptr<const std::string> data,
-                 optional<Timestamp> modified,
-                 optional<Timestamp> expires,
+    void setData(optional<std::shared_ptr<const std::string>> data,
+                 optional<Timestamp> modified_,
+                 optional<Timestamp> expires_,
                  bool complete);
 
 private: