special treatment large oplog attachments v2 (#5)

- Bugfix: Install Ctrl+C handler earlier when doing `zen oplog-export` and `zen oplog-export` to properly cancel jobs
- Improvement: Add ability to block a set of CAS entries from GC in project store
- Improvement: Large attachments and loose files are now split into smaller chunks and stored in blocks during oplog export

1 files changed, 4 insertions, 3 deletions

diff --git a/src/zencore/iohash.cpp b/src/zencore/iohash.cpp
index cedee913a..a6bf25f6c 100644
--- a/src/zencore/iohash.cpp
+++ b/src/zencore/iohash.cpp
@@ -31,14 +31,15 @@ IoHash::HashBuffer(const CompositeBuffer& Buffer)
 
 	for (const SharedBuffer& Segment : Buffer.GetSegments())
 	{
-		size_t SegmentSize = Segment.GetSize();
-		if (SegmentSize >= (65536 + 32768) && Segment.IsFileReference())
+		size_t				SegmentSize	  = Segment.GetSize();
+		static const size_t BufferingSize = 512 * 1024;
+		if (SegmentSize >= (BufferingSize + BufferingSize / 2) && Segment.IsFileReference())
 		{
 			const IoBuffer SegmentBuffer = Segment.AsIoBuffer();
 			size_t		   Offset		 = 0;
 			while (Offset < SegmentSize)
 			{
-				size_t	 ChunkSize = Min<size_t>(SegmentSize - Offset, 65536u);
+				size_t	 ChunkSize = Min<size_t>(SegmentSize - Offset, BufferingSize);
 				IoBuffer SubRange(SegmentBuffer, Offset, ChunkSize);
 				Hasher.Append(SubRange.GetData(), ChunkSize);
 				Offset += ChunkSize;