structured cache: return unique_ptr from Create*Batch factoriessb/fix-batch-ptr

- ZenCacheNamespace::CreatePutBatch/CreateGetBatch now return
  std::unique_ptr so ownership is explicit at the call site
- ZenCacheNamespace::PutBatchHandle/GetBatchHandle own their disk-layer
  handle and clean it up in the destructor, so the public
  DeletePutBatch/DeleteGetBatch entry points on ZenCacheNamespace are
  removed
- ZenCacheStore::PutBatch/GetBatch store the handle as unique_ptr and
  their destructors collapse to `= default`; the try/catch wrappers are
  no longer needed since destruction is driven by the destructors of
  types that do not throw
- Disk-layer public API (CreatePutBatch, DeletePutBatch, etc.) is
  untouched because its inner batch-handle structs live in the .cpp and
  exposing them to the header to satisfy std::unique_ptr's completeness
  requirement would leak implementation details

1 files changed, 11 insertions, 13 deletions

diff --git a/src/zenstore/include/zenstore/cache/structuredcachestore.h b/src/zenstore/include/zenstore/cache/structuredcachestore.h
index 3722a0d31..16be04ace 100644
--- a/src/zenstore/include/zenstore/cache/structuredcachestore.h
+++ b/src/zenstore/include/zenstore/cache/structuredcachestore.h
@@ -85,14 +85,12 @@ public:
 	~ZenCacheNamespace();
 
 	struct PutBatchHandle;
-	PutBatchHandle* CreatePutBatch(ZenCachePutResultVec_t& OutResults);
-	void			CommitPutBatch(PutBatchHandle* Batch);
-	void			DeletePutBatch(PutBatchHandle* Batch) noexcept;
+	std::unique_ptr<PutBatchHandle> CreatePutBatch(ZenCachePutResultVec_t& OutResults);
+	void							CommitPutBatch(PutBatchHandle* Batch);
 
 	struct GetBatchHandle;
-	GetBatchHandle* CreateGetBatch(ZenCacheValueVec_t& OutResults);
-	void			CommitGetBatch(GetBatchHandle* Batch);
-	void			DeleteGetBatch(GetBatchHandle* Batch) noexcept;
+	std::unique_ptr<GetBatchHandle> CreateGetBatch(ZenCacheValueVec_t& OutResults);
+	void							CommitGetBatch(GetBatchHandle* Batch);
 
 	bool	  Get(std::string_view Bucket, const IoHash& HashKey, ZenCacheValue& OutValue);
 	void	  Get(std::string_view Bucket, const IoHash& HashKey, GetBatchHandle& OptionalBatchHandle);
@@ -217,9 +215,9 @@ public:
 		~PutBatch();
 
 	private:
-		ZenCacheStore&					   m_CacheStore;
-		ZenCacheNamespace*				   m_Store				  = nullptr;
-		ZenCacheNamespace::PutBatchHandle* m_NamespaceBatchHandle = nullptr;
+		ZenCacheStore&									   m_CacheStore;
+		ZenCacheNamespace*								   m_Store = nullptr;
+		std::unique_ptr<ZenCacheNamespace::PutBatchHandle> m_NamespaceBatchHandle;
 
 		friend class ZenCacheStore;
 	};
@@ -232,10 +230,10 @@ public:
 		~GetBatch();
 
 	private:
-		ZenCacheStore&					   m_CacheStore;
-		ZenCacheNamespace*				   m_Store				  = nullptr;
-		ZenCacheNamespace::GetBatchHandle* m_NamespaceBatchHandle = nullptr;
-		ZenCacheValueVec_t&				   Results;
+		ZenCacheStore&									   m_CacheStore;
+		ZenCacheNamespace*								   m_Store = nullptr;
+		std::unique_ptr<ZenCacheNamespace::GetBatchHandle> m_NamespaceBatchHandle;
+		ZenCacheValueVec_t&								   Results;
 		friend class ZenCacheStore;
 	};