allow serializing empty shared_ptr

2 files changed, 22 insertions, 11 deletions

diff --git a/serialize/tile-atlas.cpp b/serialize/tile-atlas.cpp
index d5350851..fcbb371d 100644
--- a/serialize/tile-atlas.cpp
+++ b/serialize/tile-atlas.cpp
@@ -15,16 +15,23 @@ using proxy_atlas = std::tuple<std::string, Vector2ub>;
 
 void adl_serializer<std::shared_ptr<tile_atlas>>::to_json(json& j, const std::shared_ptr<const tile_atlas>& x)
 {
-    fm_assert(x);
     using nlohmann::to_json;
-    to_json(j, proxy_atlas{x->name(), x->num_tiles2()});
+    if (!x)
+        j = nullptr;
+    else
+        to_json(j, proxy_atlas{x->name(), x->num_tiles2()});
 }
 
 void adl_serializer<std::shared_ptr<tile_atlas>>::from_json(const json& j, std::shared_ptr<tile_atlas>& x)
 {
-    proxy_atlas proxy = j;
-    const auto& [name, num_tiles] = proxy;
-    x = loader.tile_atlas(name, num_tiles);
+    if (j.is_null())
+        x = nullptr;
+    else
+    {
+        proxy_atlas proxy = j;
+        const auto& [name, num_tiles] = proxy;
+        x = loader.tile_atlas(name, num_tiles);
+    }
 }
 
 } // namespace nlohmann
diff --git a/serialize/world.cpp b/serialize/world.cpp
index 8b6f84d7..7bdf8ba6 100644
--- a/serialize/world.cpp
+++ b/serialize/world.cpp
@@ -26,10 +26,10 @@ NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(global_coords_, chunk, local)
 
 } // namespace floormat
 
-using namespace floormat;
-
 namespace nlohmann {
 
+using namespace floormat;
+
 template<>
 struct adl_serializer<std::shared_ptr<chunk>> final {
     static void to_json(json& j, const std::shared_ptr<const chunk>& x);
@@ -38,16 +38,20 @@ struct adl_serializer<std::shared_ptr<chunk>> final {
 
 void adl_serializer<std::shared_ptr<chunk>>::to_json(json& j, const std::shared_ptr<const chunk>& val)
 {
-    fm_assert(val);
     using nlohmann::to_json;
-    j = *val;
+    if (!val)
+        j = nullptr;
+    else
+        j = *val;
 }
 
 void adl_serializer<std::shared_ptr<chunk>>::from_json(const json& j, std::shared_ptr<chunk>& val)
 {
-    val = std::make_shared<chunk>();
     using nlohmann::from_json;
-    *val = j;
+    if (j.is_null())
+        val = nullptr;
+    else
+        *(val = std::make_shared<chunk>()) = j;
 }
 
 void adl_serializer<chunk_coords>::to_json(json& j, const chunk_coords& val) { using nlohmann::to_json; to_json(j, val); }