Thin facade over Merkle<std::string> for multigroup snapshots. More...

#include "IStorageBackend.h"
#include <string>
#include <utility>
#include <vector>

Namespaces
namespace	nt
	Contains the Relational NT runtime managers and API facade.

Typedefs
using	nt::MultigroupCodec::RelationEntry = std::pair<std::string, std::string>
	One entry in a multigroup snapshot: (relation_name, root_hex).

Functions
std::string	nt::MultigroupCodec::Build (IStorageBackend &store, const std::vector< RelationEntry > &relations)
	Build a multigroup tree from a list of (name, root) entries.
std::vector< RelationEntry >	nt::MultigroupCodec::List (IStorageBackend &store, const std::string &root_hex)
	Enumerate all (name, root_hex) pairs at a multigroup root.
std::string	nt::MultigroupCodec::InsertOne (IStorageBackend &store, const std::string &root_hex, const std::string &relation_name, const std::string &relation_root_hex)
	Insert or overwrite one (relation_name → root_hex) entry.
std::string	nt::MultigroupCodec::RemoveOne (IStorageBackend &store, const std::string &root_hex, const std::string &relation_name)
	Remove one relation entry from the multigroup tree.
std::string	nt::MultigroupCodec::Lookup (IStorageBackend &store, const std::string &root_hex, const std::string &relation_name)
	Look up one relation's root hex by name.

Detailed Description

Thin facade over Merkle<std::string> for multigroup snapshots.

A multigroup snapshot is a Merkle<std::string> B-tree mapping each relation name to that relation's merkle root. The snapshot identifier is the hex hash of the tree's root node — the same path-localised content addressing used at the tuple level inside each relation.

Stored relations and ephemeral relations are represented uniformly: only the relation's name and its current merkle_root participate in the tree, regardless of how that root was derived.

The codec used to be a flat SHA256(sorted [(name, root)]) over a single blob. That collapsed all relations into one rehash on any mutation. With the merkle B-tree, a single relation update touches O(log_B(n_rels)) nodes on the way to the new root — sibling subtrees stay byte-identical.

RelationEntry is (relation_name, relation_root_hex). Both forms are hex strings on the wire; the codec hex-decodes internally before handing payloads to Merkle<std::string>.

Function Documentation

◆ Build()

std::string nt::MultigroupCodec::Build	(	IStorageBackend &	store,
		const std::vector< RelationEntry > &	relations )

Build a multigroup tree from a list of (name, root) entries.

Each Insert advances the root through O(log_B) nodes. The final root hash is the snapshot identifier. The list need not be pre-sorted — the merkle B-tree imposes order intrinsically.

Parameters

store	KV backend; receives all node blobs.
relations	Entries to load. Duplicates collapse to the last value.

Returns: Root node hash (empty string when relations is empty).

◆ InsertOne()

std::string nt::MultigroupCodec::InsertOne	(	IStorageBackend &	store,
		const std::string &	root_hex,
		const std::string &	relation_name,
		const std::string &	relation_root_hex )

Insert or overwrite one (relation_name → root_hex) entry.

Equivalent to Merkle<std::string>::Insert after hex-decoding the payload. The caller threads the returned root hash through subsequent mutations. Pass an empty root_hex for the prior-state argument to start from an empty tree.

◆ List()

std::vector< RelationEntry > nt::MultigroupCodec::List	(	IStorageBackend &	store,
		const std::string &	root_hex )

Enumerate all (name, root_hex) pairs at a multigroup root.

Pages the entire tree (offset 0, no limit). Returned entries are in key-sorted order. Empty input root yields an empty list.

◆ Lookup()

std::string nt::MultigroupCodec::Lookup	(	IStorageBackend &	store,
		const std::string &	root_hex,
		const std::string &	relation_name )

Look up one relation's root hex by name.

Returns: Hex root, or empty string when the name is absent.

◆ RemoveOne()

std::string nt::MultigroupCodec::RemoveOne	(	IStorageBackend &	store,
		const std::string &	root_hex,
		const std::string &	relation_name )

Remove one relation entry from the multigroup tree.

Returns the new root hash; empty when the tree becomes empty.

Namespaces

Typedefs