Enforce Overwrite Prevention According To Cache Policy

Overwrite with differing value should be denied if QueryLocal is not present and StoreLocal is present.  Overwrite with equal value should succeed regardless of policy flags.

3 files changed, 18 insertions, 10 deletions

diff --git a/src/zenstore/include/zenstore/cache/cachedisklayer.h b/src/zenstore/include/zenstore/cache/cachedisklayer.h
index b0b4f22cb..7de707a7f 100644
--- a/src/zenstore/include/zenstore/cache/cachedisklayer.h
+++ b/src/zenstore/include/zenstore/cache/cachedisklayer.h
@@ -178,10 +178,11 @@ public:
 	PutBatchHandle* BeginPutBatch(std::vector<bool>& OutResult);
 	void			EndPutBatch(PutBatchHandle* Batch) noexcept;
 
-	void Put(std::string_view	  Bucket,
+	bool Put(std::string_view	  Bucket,
 			 const IoHash&		  HashKey,
 			 const ZenCacheValue& Value,
 			 std::span<IoHash>	  References,
+			 bool				  Overwrite,
 			 PutBatchHandle*	  OptionalBatchHandle);
 	bool Drop();
 	bool DropBucket(std::string_view Bucket);
@@ -228,13 +229,17 @@ public:
 		void			Get(const IoHash& HashKey, GetBatchHandle& BatchHandle);
 
 		struct PutBatchHandle;
-		PutBatchHandle* BeginPutBatch(std::vector<bool>& OutResult);
-		void			EndPutBatch(PutBatchHandle* Batch) noexcept;
-		void	 Put(const IoHash& HashKey, const ZenCacheValue& Value, std::span<IoHash> References, PutBatchHandle* OptionalBatchHandle);
-		uint64_t MemCacheTrim(GcClock::TimePoint ExpireTime);
-		bool	 Drop();
-		void	 Flush();
-		void	 ScrubStorage(ScrubContext& Ctx);
+		PutBatchHandle*			BeginPutBatch(std::vector<bool>& OutResult);
+		void					EndPutBatch(PutBatchHandle* Batch) noexcept;
+		bool					Put(const IoHash&		 HashKey,
+									const ZenCacheValue& Value,
+									std::span<IoHash>	 References,
+									bool				 Overwrite,
+									PutBatchHandle*		 OptionalBatchHandle);
+		uint64_t				MemCacheTrim(GcClock::TimePoint ExpireTime);
+		bool					Drop();
+		void					Flush();
+		void					ScrubStorage(ScrubContext& Ctx);
 		RwLock::SharedLockScope GetGcReferencerLock();
 
 		struct ReferencesStats
diff --git a/src/zenstore/include/zenstore/cache/cacherpc.h b/src/zenstore/include/zenstore/cache/cacherpc.h
index da8cf69fe..d489a5386 100644
--- a/src/zenstore/include/zenstore/cache/cacherpc.h
+++ b/src/zenstore/include/zenstore/cache/cacherpc.h
@@ -60,6 +60,7 @@ enum class PutResult
 {
 	Success,
 	Fail,
+	Conflict,
 	Invalid,
 };
 
diff --git a/src/zenstore/include/zenstore/cache/structuredcachestore.h b/src/zenstore/include/zenstore/cache/structuredcachestore.h
index 82fec9b0e..1b5e0b76b 100644
--- a/src/zenstore/include/zenstore/cache/structuredcachestore.h
+++ b/src/zenstore/include/zenstore/cache/structuredcachestore.h
@@ -91,10 +91,11 @@ public:
 
 	bool Get(std::string_view Bucket, const IoHash& HashKey, ZenCacheValue& OutValue);
 	void Get(std::string_view Bucket, const IoHash& HashKey, GetBatchHandle& OptionalBatchHandle);
-	void Put(std::string_view	  Bucket,
+	bool Put(std::string_view	  Bucket,
 			 const IoHash&		  HashKey,
 			 const ZenCacheValue& Value,
 			 std::span<IoHash>	  References,
+			 bool				  Overwrite,
 			 PutBatchHandle*	  OptionalBatchHandle = nullptr);
 
 	bool DropBucket(std::string_view Bucket);
@@ -243,12 +244,13 @@ public:
 			 const IoHash&				HashKey,
 			 GetBatch&					BatchHandle);
 
-	void Put(const CacheRequestContext& Context,
+	bool Put(const CacheRequestContext& Context,
 			 std::string_view			Namespace,
 			 std::string_view			Bucket,
 			 const IoHash&				HashKey,
 			 const ZenCacheValue&		Value,
 			 std::span<IoHash>			References,
+			 bool						Overwrite,
 			 PutBatch*					OptionalBatchHandle = nullptr);
 
 	bool DropBucket(std::string_view Namespace, std::string_view Bucket);