Added logic to guard against accidental file move in file CAS fast path

Now verifies the chunk is referencing an entire file before moving it into place

3 files changed, 25 insertions, 5 deletions

diff --git a/zencore/include/zencore/iobuffer.h b/zencore/include/zencore/iobuffer.h
index 7e7182997..7cf497527 100644
--- a/zencore/include/zencore/iobuffer.h
+++ b/zencore/include/zencore/iobuffer.h
@@ -90,6 +90,7 @@ public:
 	}
 
 	inline bool IsImmutable() const { return !(m_Flags & kIsMutable); }
+	inline bool IsWholeFile() const { return !!(m_Flags & kIsWholeFile); }
 	inline bool IsNull() const { return m_DataBytes == 0; }
 
 	inline IoBufferExtendedCore*	   ExtendedCore();
@@ -123,6 +124,18 @@ public:
 		}
 	}
 
+	inline void SetIsWholeFile(bool NewState)
+	{
+		if (NewState)
+		{
+			m_Flags |= kIsWholeFile;
+		}
+		else
+		{
+			m_Flags |= ~kIsWholeFile;
+		}
+	}
+
 	inline uint32_t GetRefCount() const { return m_RefCount; }
 
 protected:
@@ -139,6 +152,7 @@ protected:
 		kIsExtended		= 1 << 2,  // Is actually a SharedBufferExtendedCore
 		kIsMaterialized = 1 << 3,  // Data pointers are valid
 		kLowLevelAlloc	= 1 << 4,  // Using direct memory allocation
+		kIsWholeFile	= 1 << 5,  // References an entire file
 	};
 
 	void* AllocateBuffer(size_t InSize, size_t Alignment);
@@ -262,6 +276,7 @@ public:
 	inline			 operator bool() const { return !m_Core->IsNull(); }
 	ZENCORE_API void MakeOwned() { return m_Core->MakeOwned(); }
 	inline bool		 IsOwned() const { return m_Core->IsOwned(); }
+	inline bool		 IsWholeFile() const { return m_Core->IsWholeFile(); }
 	const void*		 Data() const { return m_Core->DataPointer(); }
 	const size_t	 Size() const { return m_Core->DataBytes(); }
 	ZENCORE_API bool GetFileReference(IoBufferFileReference& OutRef) const;
@@ -272,6 +287,7 @@ private:
 	IoBuffer(IoBufferCore* Core) : m_Core(Core) {}
 
 	friend class SharedBuffer;
+	friend class IoBufferBuilder;
 };
 
 class IoBufferBuilder
@@ -281,8 +297,6 @@ public:
 	ZENCORE_API static IoBuffer MakeFromTemporaryFile(const wchar_t* FileName, uint64_t Offset = 0, uint64_t Size = ~0ull);
 	ZENCORE_API static IoBuffer MakeFromFileHandle(void* FileHandle, uint64_t Offset = 0, uint64_t Size = ~0ull);
 	inline static IoBuffer		MakeCloneFromMemory(const void* Ptr, size_t Sz) { return IoBuffer(IoBuffer::Clone, Ptr, Sz); }
-
-private:
 };
 
 void iobuffer_forcelink();
diff --git a/zencore/iobuffer.cpp b/zencore/iobuffer.cpp
index e74287c48..d32a30358 100644
--- a/zencore/iobuffer.cpp
+++ b/zencore/iobuffer.cpp
@@ -339,7 +339,7 @@ IoBufferBuilder::MakeFromTemporaryFile(const wchar_t* FileName, uint64_t Offset,
 
 	// We need to open with DELETE since this is used for the case
 	// when a file has been written to a staging directory, and is going
-	// to be moved in place.
+	// to be moved in place
 
 	HRESULT hRes = DataFile.Create(FileName, GENERIC_READ | DELETE, FILE_SHARE_READ | FILE_SHARE_DELETE, OPEN_EXISTING);
 
@@ -361,7 +361,10 @@ IoBufferBuilder::MakeFromTemporaryFile(const wchar_t* FileName, uint64_t Offset,
 			}
 		}
 
-		return IoBuffer(IoBuffer::File, DataFile.Detach(), Offset, Size);
+		IoBuffer Iob(IoBuffer::File, DataFile.Detach(), Offset, Size);
+		Iob.m_Core->SetIsWholeFile(true);
+
+		return Iob;
 	}
 
 	return {};
diff --git a/zenstore/filecas.cpp b/zenstore/filecas.cpp
index 0011ddec6..1e9b50e63 100644
--- a/zenstore/filecas.cpp
+++ b/zenstore/filecas.cpp
@@ -63,8 +63,11 @@ FileCasStrategy::MakeShardedPath(WideStringBuilderBase& ShardedPath, const IoHas
 CasStore::InsertResult
 FileCasStrategy::InsertChunk(IoBuffer Chunk, const IoHash& ChunkHash)
 {
+	// File-based chunks have special case handling whereby we move the file into
+	// place in the file store directory, thus avoiding unnecessary copying
+
 	IoBufferFileReference FileRef;
-	if (Chunk.GetFileReference(/* out */ FileRef))
+	if (Chunk.IsWholeFile() && Chunk.GetFileReference(/* out */ FileRef))
 	{
 		size_t							 Shard2len = 0;
 		ExtendableWideStringBuilder<128> ShardedPath;