Switch FEATURE to use PagedEntityContainer<FEATURE> as backing st…

…orage

1. Split the feature storage into pages containing 128 features
2. Disable slot reuse to guard against memory-related issues
   when some object pointers won't get updated properly,
   e.g. when transitioning between the base and offworld missions.

Signed-off-by: Pavel Solodovnikov <[email protected]>

src/feature.cpp

@@ -183,14 +183,10 @@ FEATURE *buildFeature(FEATURE_STATS *psStats, UDWORD x, UDWORD y, bool FromSave)
 /* Create a feature on the map */
 FEATURE *buildFeature(FEATURE_STATS *psStats, UDWORD x, UDWORD y, bool FromSave, uint32_t id)
 {
-	//try and create the Feature
-	FEATURE *psFeature = new FEATURE(id, psStats);
+	//try and create the Feature, obtain stable address.
+	FEATURE& feature = GlobalFeatureContainer().emplace(id, psStats);
+	FEATURE* psFeature = &feature;
 
-	if (psFeature == nullptr)
-	{
-		debug(LOG_WARNING, "Feature couldn't be built.");
-		return nullptr;
-	}
 	//add the feature to the list - this enables it to be drawn whilst being built
 	addFeature(psFeature);
 
@@ -556,3 +552,9 @@ StructureBounds getStructureBounds(FEATURE_STATS const *stats, Vector2i pos)
 	const Vector2i map = map_coord(pos) - size / 2;
 	return StructureBounds(map, size);
 }
+
+FeatureContainer& GlobalFeatureContainer()
+{
+	static FeatureContainer instance;
+	return instance;
+}

src/feature.h

@@ -26,6 +26,7 @@
 
 #include "objectdef.h"
 #include "lib/framework/wzconfig.h"
+#include "lib/framework/paged_entity_container.h"
 
 /* The statistics for the features */
 extern std::vector<FEATURE_STATS> asFeatureStats;
@@ -82,4 +83,10 @@ static inline FEATURE const *castFeature(SIMPLE_OBJECT const *psObject)
 	return isFeature(psObject) ? (FEATURE const *)psObject : (FEATURE const *)nullptr;
 }
 
+// Split the feature storage into pages containing 128 features, disable slot reuse
+// to guard against memory-related issues when some object pointers won't get
+// updated properly, e.g. when transitioning between the base and offworld missions.
+using FeatureContainer = PagedEntityContainer<FEATURE, 128, false>;
+FeatureContainer& GlobalFeatureContainer();
+
 #endif // __INCLUDED_SRC_FEATURE_H__

src/objmem.cpp

@@ -86,10 +86,9 @@ bool objmemInitialise()
 /* Release the object heaps */
 void objmemShutdown()
 {
-	auto& droidContainer = GlobalDroidContainer();
-	droidContainer.clear();
-	auto& structContainer = GlobalStructContainer();
-	structContainer.clear();
+	GlobalDroidContainer().clear();
+	GlobalStructContainer().clear();
+	GlobalFeatureContainer().clear();
 }
 
 // Check that psVictim is not referred to by any other object in the game. We can dump out some extra data in debug builds that help track down sources of dangling pointer errors.
@@ -244,6 +243,14 @@ bool objmemDestroy(BASE_OBJECT *psObj, bool checkRefs)
 		ASSERT(it != structContainer.end(), "Structure not found in the global container!");
 		structContainer.erase(it);
 	}
+	else if (psObj->type == OBJ_FEATURE)
+	{
+		// Features are managed by a separate feature container.
+		auto& featureContainer = GlobalFeatureContainer();
+		auto it = featureContainer.find(*static_cast<FEATURE*>(psObj));
+		ASSERT(it != featureContainer.end(), "Feature not found in the global container!");
+		featureContainer.erase(it);
+	}
 	else
 	{
 		delete psObj;
@@ -497,6 +504,22 @@ struct GlobalEntityContainerTraits<STRUCTURE>
 	}
 };
 
+template <>
+struct GlobalEntityContainerTraits<FEATURE>
+{
+	using StorageType = FeatureContainer;
+
+	static FeatureContainer& getContainer()
+	{
+		return GlobalFeatureContainer();
+	}
+
+	static const char* entityName()
+	{
+		return "Feature";
+	}
+};
+
 template <typename Entity, unsigned PlayerCount>
 static void freeAllEntitiesImpl(PerPlayerObjectLists<Entity, PlayerCount>& entityLists)
 {
@@ -692,7 +715,7 @@ void killFeature(FEATURE *psDel)
 /* Remove all features */
 void freeAllFeatures()
 {
-	releaseAllObjectsInList(apsFeatureLists);
+	freeAllEntitiesImpl<FEATURE, MAX_PLAYERS>(apsFeatureLists);
 }
 
 /**************************  FLAG_POSITION ********************************/