safer partial requests (#82)

* fix partial cache miss logging
* Handle zero size partial requests safer

2 files changed, 48 insertions, 37 deletions

diff --git a/src/zencore/compress.cpp b/src/zencore/compress.cpp
index 143317e65..29c1d9256 100644
--- a/src/zencore/compress.cpp
+++ b/src/zencore/compress.cpp
@@ -705,10 +705,13 @@ BlockDecoder::DecompressToComposite(DecoderContext&		 Context,
 									const uint64_t		 RawOffset,
 									const uint64_t		 RawSize) const
 {
-	UniqueBuffer Buffer = UniqueBuffer::Alloc(RawSize);
-	if (TryDecompressTo(Context, Source, Header, HeaderView, RawOffset, Buffer))
+	if (RawSize > 0)
 	{
-		return CompositeBuffer(Buffer.MoveToShared());
+		UniqueBuffer Buffer = UniqueBuffer::Alloc(RawSize);
+		if (TryDecompressTo(Context, Source, Header, HeaderView, RawOffset, Buffer))
+		{
+			return CompositeBuffer(Buffer.MoveToShared());
+		}
 	}
 	return CompositeBuffer();
 }
@@ -1442,13 +1445,16 @@ CompressedBuffer::DecodeRawHash() const
 CompressedBuffer
 CompressedBuffer::CopyRange(uint64_t RawOffset, uint64_t RawSize) const
 {
-	CompressedBuffer	 Range;
-	detail::BufferHeader Header;
-	UniqueBuffer		 RawHeaderData;
-	if (ReadHeader(CompressedData, Header, &RawHeaderData))
+	CompressedBuffer Range;
+	if (RawSize > 0)
 	{
-		const uint64_t TotalRawSize = RawSize < ~uint64_t(0) ? RawSize : Header.TotalRawSize - RawOffset;
-		Range.CompressedData		= CopyCompressedRange(Header, RawHeaderData.GetView(), CompressedData, RawOffset, TotalRawSize);
+		detail::BufferHeader Header;
+		UniqueBuffer		 RawHeaderData;
+		if (ReadHeader(CompressedData, Header, &RawHeaderData))
+		{
+			const uint64_t TotalRawSize = RawSize < ~uint64_t(0) ? RawSize : Header.TotalRawSize - RawOffset;
+			Range.CompressedData		= CopyCompressedRange(Header, RawHeaderData.GetView(), CompressedData, RawOffset, TotalRawSize);
+		}
 	}
 	return Range;
 }
@@ -1456,13 +1462,16 @@ CompressedBuffer::CopyRange(uint64_t RawOffset, uint64_t RawSize) const
 CompressedBuffer
 CompressedBuffer::GetRange(uint64_t RawOffset, uint64_t RawSize) const
 {
-	CompressedBuffer	 Range;
-	detail::BufferHeader Header;
-	UniqueBuffer		 RawHeaderData;
-	if (ReadHeader(CompressedData, Header, &RawHeaderData))
+	CompressedBuffer Range;
+	if (RawSize > 0)
 	{
-		const uint64_t TotalRawSize = RawSize < ~uint64_t(0) ? RawSize : Header.TotalRawSize - RawOffset;
-		Range.CompressedData		= GetCompressedRange(Header, RawHeaderData.GetView(), CompressedData, RawOffset, TotalRawSize);
+		detail::BufferHeader Header;
+		UniqueBuffer		 RawHeaderData;
+		if (ReadHeader(CompressedData, Header, &RawHeaderData))
+		{
+			const uint64_t TotalRawSize = RawSize < ~uint64_t(0) ? RawSize : Header.TotalRawSize - RawOffset;
+			Range.CompressedData		= GetCompressedRange(Header, RawHeaderData.GetView(), CompressedData, RawOffset, TotalRawSize);
+		}
 	}
 	return Range;
 }
@@ -1471,7 +1480,7 @@ bool
 CompressedBuffer::TryDecompressTo(MutableMemoryView RawView, uint64_t RawOffset) const
 {
 	using namespace detail;
-	if (CompressedData)
+	if (CompressedData && RawView.GetSize() > 0)
 	{
 		const BufferHeader Header = BufferHeader::Read(CompressedData);
 		if (Header.Magic == BufferHeader::ExpectedMagic)
@@ -1695,28 +1704,31 @@ CompressedBufferReader::TryDecompressTo(const MutableMemoryView RawView, const u
 SharedBuffer
 CompressedBufferReader::Decompress(const uint64_t RawOffset, const uint64_t RawSize)
 {
-	using namespace detail;
-	BufferHeader Header;
-	MemoryView	 HeaderView;
-	if (TryReadHeader(Header, HeaderView))
+	if (RawSize > 0)
 	{
-		const uint64_t TotalRawSize	 = Header.TotalRawSize;
-		const uint64_t RawSizeToCopy = RawSize == MAX_uint64 ? TotalRawSize - RawOffset : RawSize;
-		if (RawOffset <= TotalRawSize && RawSizeToCopy <= TotalRawSize - RawOffset)
+		using namespace detail;
+		BufferHeader Header;
+		MemoryView	 HeaderView;
+		if (TryReadHeader(Header, HeaderView))
 		{
-			if (const BaseDecoder* const Decoder = GetDecoder(Header.Method))
+			const uint64_t TotalRawSize	 = Header.TotalRawSize;
+			const uint64_t RawSizeToCopy = RawSize == MAX_uint64 ? TotalRawSize - RawOffset : RawSize;
+			if (RawOffset <= TotalRawSize && RawSizeToCopy <= TotalRawSize - RawOffset)
 			{
-				UniqueBuffer RawData = UniqueBuffer::Alloc(RawSizeToCopy);
-				if (Decoder->TryDecompressTo(
-						Context,
-						SourceArchive ? static_cast<const DecoderSource&>(ArchiveDecoderSource(*SourceArchive, Context.HeaderOffset))
-									  : static_cast<const DecoderSource&>(BufferDecoderSource(SourceBuffer->GetCompressed())),
-						Header,
-						HeaderView,
-						RawOffset,
-						RawData))
+				if (const BaseDecoder* const Decoder = GetDecoder(Header.Method))
 				{
-					return RawData.MoveToShared();
+					UniqueBuffer RawData = UniqueBuffer::Alloc(RawSizeToCopy);
+					if (Decoder->TryDecompressTo(
+							Context,
+							SourceArchive ? static_cast<const DecoderSource&>(ArchiveDecoderSource(*SourceArchive, Context.HeaderOffset))
+										  : static_cast<const DecoderSource&>(BufferDecoderSource(SourceBuffer->GetCompressed())),
+							Header,
+							HeaderView,
+							RawOffset,
+							RawData))
+					{
+						return RawData.MoveToShared();
+					}
 				}
 			}
 		}
diff --git a/src/zenstore/cache/cacherpc.cpp b/src/zenstore/cache/cacherpc.cpp
index f12cee923..d56ceb98e 100644
--- a/src/zenstore/cache/cacherpc.cpp
+++ b/src/zenstore/cache/cacherpc.cpp
@@ -1662,8 +1662,7 @@ CacheRpcHandler::WriteGetCacheChunksResponse([[maybe_unused]] const CacheRequest
 							}
 						}
 
-						CompressedBuffer PartialValue =
-							Request.Value.GetRange(Request.RequestedOffset, Request.RequestedSize == 0 ? 1u : Request.RequestedSize);
+						CompressedBuffer PartialValue = Request.Value.GetRange(Request.RequestedOffset, Request.RequestedSize);
 
 						if (PartialValue)
 						{
@@ -1684,10 +1683,10 @@ CacheRpcHandler::WriteGetCacheChunksResponse([[maybe_unused]] const CacheRequest
 						else
 						{
 							ZEN_WARN("GETCACHECHUNKS MISS (rawsize: {}, offset: {}, size: {}) - '{}/{}/{}/{}' in {}",
-									 Namespace,
 									 Request.Value.DecodeRawSize(),
 									 Request.RequestedOffset,
 									 Request.RequestedSize,
+									 Namespace,
 									 Request.Key->Key.Bucket,
 									 Request.Key->Key.Hash,
 									 Request.Key->ValueId,