setBlock

Sets a single block hash and, if the surrounding subtree is now fully known, verifies it against the already-known ancestor hashes, marking the affected blocks as verified on success. A focused analogue of merkle_tree::set_block for the full-tree representation.

Specifically: it writes the block hash, finds the smallest enclosing piece (or the whole tree, for single-block pieces), and if every leaf and the piece root are known it folds the leaves and compares against the stored piece root.