Added preliminary CbPackageReader, for handling incremental compact binary package streaming

1 files changed, 53 insertions, 2 deletions

diff --git a/zenhttp/include/zenhttp/httpshared.h b/zenhttp/include/zenhttp/httpshared.h
index 92c1ef9c6..2e728577d 100644
--- a/zenhttp/include/zenhttp/httpshared.h
+++ b/zenhttp/include/zenhttp/httpshared.h
@@ -13,10 +13,23 @@ class IoBuffer;
 class CbPackage;
 class CompositeBuffer;
 
+/**	   _____ _     _____           _
+	  / ____| |   |  __ \         | |
+	 | |    | |__ | |__) |_ _  ___| | ____ _  __ _  ___
+	 | |    | '_ \|  ___/ _` |/ __| |/ / _` |/ _` |/ _ \
+	 | |____| |_) | |  | (_| | (__|   < (_| | (_| |  __/
+	  \_____|_.__/|_|   \__,_|\___|_|\_\__,_|\__, |\___|
+											  __/ |
+											 |___/
+
+	Structures and code related to handling CbPackage transactions
+
+ */
+
 struct CbPackageHeader
 {
 	uint32_t HeaderMagic;
-	uint32_t AttachmentCount;
+	uint32_t AttachmentCount;  // TODO: should add ability to opt out of implicit root document?
 	uint32_t Reserved1;
 	uint32_t Reserved2;
 };
@@ -27,7 +40,7 @@ static constinit uint32_t kCbPkgMagic = 0xaa77aacc;
 
 struct CbAttachmentEntry
 {
-	uint64_t AttachmentSize;
+	uint64_t PayloadSize;
 	uint32_t Flags;
 	IoHash	 AttachmentHash;
 
@@ -35,6 +48,7 @@ struct CbAttachmentEntry
 	{
 		kIsCompressed = (1u << 0),	// Is marshaled using compressed buffer storage format
 		kIsObject	  = (1u << 1),	// Is compact binary object
+		kIsError	  = (1u << 2),	// Is error (compact binary formatted) object
 	};
 };
 
@@ -48,4 +62,41 @@ CbPackage			  ParsePackageMessage(
 		return IoBuffer{Size};
 				});
 
+/** Streaming reader for compact binary packages
+
+	The goal is to ultimately support zero-copy I/O, but for now there'll be some
+	copying involved on some platforms at least.
+
+  */
+class CbPackageReader
+{
+public:
+	CbPackageReader();
+	~CbPackageReader();
+
+	void SetPayloadBufferCreator(std::function<IoBuffer(const IoHash& Cid, uint64_t Size)> CreateBuffer);
+
+	/** Process header data
+	 */
+	uint64_t ProcessHeaderData(const void* Data, uint64_t DataBytes);
+
+	std::span<IoBuffer> GetPayloadBuffers() { return m_PayloadBuffers; }
+
+private:
+	enum class State
+	{
+		kInitialState,
+		kReadingHeader,
+		kReadingAttachmentEntries,
+		kReadingBuffers
+	} m_CurrentState = State::kInitialState;
+
+	std::function<IoBuffer(const IoHash& Cid, uint64_t Size)> m_CreateBuffer;
+	std::vector<IoBuffer>									  m_PayloadBuffers;
+	std::vector<CbAttachmentEntry>							  m_AttachmentEntries;
+	CbPackageHeader											  m_PackageHeader;
+};
+
+void forcelink_httpshared();
+
 }  // namespace zen