Crate cumulus_primitives_spec_messaging 

Primitives for the Speculative Messaging protocol.

A sender parachain keeps each outgoing stream as an MMR and commits all stream roots as one StreamsRoot (a keyed trie). Messages travel between collators; the relay chain only checks that each receiver’s Requires matches a sender’s Provides.

The relay-visible types (StreamsRoot, RequiresSet) are in polkadot-primitives. This crate has the parachain-side types and the off-chain wire format.

Re-exports

pub use channel::ChannelId;

pub use channel::ChannelPhase;

pub use channel::InChannelState;

pub use channel::OutChannelState;

pub use channel::RegisterRead;

pub use flow_control::Register;

pub use flow_control::SpecMsgKind;

pub use flow_control::SpecMsgSignal;

pub use flow_control::WindowGrant;

pub use inherent::ConsumeItem;

pub use inherent::ConsumedStream;

pub use inherent::MessagingInherentData;

pub use inherent::Payload;

pub use inherent::INHERENT_IDENTIFIER;

pub use lift::build_requires;

pub use lift::build_requires_entry;

pub use lift::stitch;

pub use lift::ConsumptionRecord;

pub use lift::Interval;

pub use lift::LiftError;

pub use lift::LiftsBySource;

pub use lift::MMRExtensionProof;

pub use lift::MmrInclusionProof;

pub use lift::ProofError;

pub use lift::RequiresLift;

pub use lift::SourceStreams;

pub use lift::TreeInclusionProof;

pub use message::leaf_hash;

pub use message::verify_event;

pub use message::verify_exchange;

pub use message::verify_messages;

pub use message::EventRequest;

pub use message::EventResponse;

pub use message::ExchangeRequest;

pub use message::ExchangeResponse;

pub use message::ExchangeVerified;

pub use message::MessagesRequest;

pub use message::MessagesResponse;

pub use message::VerifiedEvent;

pub use message::VerifyError;

pub use message::MAX_MESSAGES_PER_RESPONSE;

pub use message::MAX_SPECULATIVE_MESSAGE_LEN;

pub use mmr::FrontierFull;

pub use mmr::MessagePosition;

pub use mmr::MmrFrontier;

pub use mmr::MmrRoot;

pub use stream::PrivateKind;

pub use stream::StreamId;

pub use stream::STREAM_ID_LEN;

pub use streams_root::StreamProof;

Modules

channel

Channel state primitives: the key and the two per-direction states the messaging pallet keeps in OutChannels / InChannels and returns from the runtime API’s out_channels() / in_channels().

flow_control

Channel flow-control types: the sender’s channel-stream leaf payload (SpecMsgKind / SpecMsgSignal) and the receiver’s out-of-band confirmation Register with its advisory WindowGrant. The pallet owns the logic: windowing, version enforcement, channel storage, the accept extrinsic.

inherent

The node/runtime consumption interface: what the runtime asks the node to fetch (ConsumedStream, via the consumed_streams() runtime API) and what the node delivers in the messaging inherent (MessagingInherentData / ConsumeItem).

lift

Requires-lift and consumption-record primitives.

message

Off-chain wire types and their verifiers.

mmr

MMR primitives for the Speculative Messaging protocol.

stream

StreamId: the parachain-structured stream key.

streams_root

StreamsRoot: the sender’s stream commitment.

Structs

StreamsRoot

The sender’s per-block stream commitment root. Defined relay-side and re-exported here. Root of a sender’s stream commitment tree: a compact binary trie keyed by the 8-byte StreamId encoding, with the streams’ MMR roots as leaves.

Constants

INNER_TAG

MMR inner node.

LEAF_TAG

MMR leaf.

LEAF_VERSION

Leaf preimage version. Versions are hash-disjoint, so the layout can change without old leaves colliding with new ones.

PEAK_TAG

MMR peak bagging.

ROOT_TAG

Stream root: H(ROOT_TAG ++ leaf_count[8, LE] ++ bag(peaks)[32]) (mmr::MmrRoot::from_bag). Binding the count stops a peer from presenting the same peaks at a forged position. The empty MMR has no peaks to bag; its root is the count-0 case, with a zero bag (mmr::empty_root).

SPMS_ENGINE_ID

Engine id of the header digest carrying a block’s StreamsRoot, deposited only by blocks that send.

TREE_INNER_TAG

Commitment-tree inner node: H(TREE_INNER_TAG ++ split_bit ++ left[32] ++ right[32]).

TREE_LEAF_TAG

Commitment-tree leaf: H(TREE_LEAF_TAG ++ key[8] ++ stream_root[32]).

Type Aliases

SpecHasher

The hash function for all of speculative messaging: leaves, MMR merges, stream and commitment-tree roots. A protocol constant. Changing it is a consensus break, so nothing here is generic over it.