fix leak in IoBuffer for manifested small chunk (#618)

* fix leak in IoBuffer for manifested small chunk. previously it would null out the `m_DataPtr` member on every path from `IoBufferExtendedCore::~IoBufferExtendedCore()` but it only really makes sense to null it out when the buffer has been memory mapped

1 files changed, 2 insertions, 2 deletions

diff --git a/src/zencore/iobuffer.cpp b/src/zencore/iobuffer.cpp
index 912f9ce4e..80d0f4ee4 100644
--- a/src/zencore/iobuffer.cpp
+++ b/src/zencore/iobuffer.cpp
@@ -209,6 +209,8 @@ IoBufferExtendedCore::~IoBufferExtendedCore()
 		uint64_t MapSize = ~uint64_t(uintptr_t(m_MmapHandle));
 		munmap(m_MappedPointer, MapSize);
 #endif
+
+		m_DataPtr = nullptr;  // prevent any buffer deallocation attempts
 	}
 
 	const uint32_t LocalFlags = m_Flags.load(std::memory_order_relaxed);
@@ -244,8 +246,6 @@ IoBufferExtendedCore::~IoBufferExtendedCore()
 			ZEN_WARN("Error reported on file handle close, reason '{}'", GetLastErrorAsString());
 		}
 	}
-
-	m_DataPtr = nullptr;
 }
 
 static constexpr size_t MappingLockCount = 128;