Implemented move-in-place for large CAS payloads

1 files changed, 35 insertions, 0 deletions

diff --git a/zencore/iobuffer.cpp b/zencore/iobuffer.cpp
index ec5d599b4..e74287c48 100644
--- a/zencore/iobuffer.cpp
+++ b/zencore/iobuffer.cpp
@@ -332,6 +332,41 @@ IoBufferBuilder::MakeFromFile(const wchar_t* FileName, uint64_t Offset, uint64_t
 	return {};
 }
 
+IoBuffer
+IoBufferBuilder::MakeFromTemporaryFile(const wchar_t* FileName, uint64_t Offset, uint64_t Size)
+{
+	CAtlFile DataFile;
+
+	// 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.
+
+	HRESULT hRes = DataFile.Create(FileName, GENERIC_READ | DELETE, FILE_SHARE_READ | FILE_SHARE_DELETE, OPEN_EXISTING);
+
+	if (SUCCEEDED(hRes))
+	{
+		ULONGLONG FileSize;
+		DataFile.GetSize(FileSize);
+
+		if (Size == ~0ull)
+		{
+			Size = FileSize;
+		}
+		else
+		{
+			// Clamp size
+			if ((Offset + Size) > FileSize)
+			{
+				Size = FileSize - Offset;
+			}
+		}
+
+		return IoBuffer(IoBuffer::File, DataFile.Detach(), Offset, Size);
+	}
+
+	return {};
+}
+
 //////////////////////////////////////////////////////////////////////////
 
 void