Add weak pointer management to RasterSource and derived classes (#3726)

include/mbgl/style/sources/raster_dem_source.hpp

@@ -18,6 +18,7 @@ public:
                     variant<std::string, Tileset> urlOrTileset,
                     uint16_t tileSize,
                     std::optional<RasterDEMOptions> options = std::nullopt);
+    ~RasterDEMSource() override;
     bool supportsLayerType(const mbgl::style::LayerTypeInfo*) const override;
 
 protected:

include/mbgl/style/sources/raster_source.hpp

@@ -16,6 +16,16 @@ public:
                  SourceType sourceType = SourceType::Raster);
 
     bool supportsLayerType(const mbgl::style::LayerTypeInfo*) const override;
+
+    mapbox::base::WeakPtr<Source> makeWeakPtr() override { return weakFactory.makeWeakPtr(); }
+
+protected:
+    // Allows derived classes (e.g. RasterDEMSource) to invalidate weak pointers
+    // early in their destructor before their own members are torn down.
+    void invalidateWeakPtrsEarly() { weakFactory.invalidateWeakPtrs(); }
+
+private:
+    mapbox::base::WeakPtrFactory<Source> weakFactory{this}; // Must remain last
 };
 
 template <>

include/mbgl/style/sources/tile_source.hpp

@@ -25,8 +25,6 @@ public:
 
     void loadDescription(FileSource&) final;
 
-    mapbox::base::WeakPtr<Source> makeWeakPtr() final { return weakFactory.makeWeakPtr(); }
-
 protected:
     Mutable<Source::Impl> createMutable() const noexcept final;
     virtual void setTilesetOverrides(Tileset& tileset);
@@ -34,8 +32,6 @@ protected:
 private:
     const variant<std::string, Tileset> urlOrTileset;
     std::unique_ptr<AsyncRequest> req;
-    mapbox::base::WeakPtrFactory<Source> weakFactory{this};
-    // Do not add members here, see `WeakPtrFactory`
 };
 
 template <>

include/mbgl/style/sources/vector_source.hpp

@@ -29,9 +29,12 @@ public:
 
     bool supportsLayerType(const mbgl::style::LayerTypeInfo*) const override;
 
+    mapbox::base::WeakPtr<Source> makeWeakPtr() override { return weakFactory.makeWeakPtr(); }
+
 private:
     std::optional<float> maxZoom;
     std::optional<float> minZoom;
+    mapbox::base::WeakPtrFactory<Source> weakFactory{this}; // Must remain last
 };
 
 template <>

src/mbgl/style/sources/raster_dem_source.cpp

@@ -18,6 +18,11 @@ RasterDEMSource::RasterDEMSource(std::string id,
     : RasterSource(std::move(id), std::move(urlOrTileset_), tileSize, SourceType::RasterDEM),
       options(std::move(options_)) {}
 
+RasterDEMSource::~RasterDEMSource() {
+    // Invalidate weak pointers before RasterDEMSource members are destroyed
+    invalidateWeakPtrsEarly();
+}
+
 bool RasterDEMSource::supportsLayerType(const mbgl::style::LayerTypeInfo* info) const {
     return mbgl::underlying_type(Tile::Kind::RasterDEM) == mbgl::underlying_type(info->tileKind);
 }