Loopback Client

type ConsensusState object

type Header object

type Misbehaviour object

interface ClientState {
  latestHeight: Height
}

interface Height {
  revisionNumber: uint64
  revisionHeight: uint64
}

function initialise(identifier: Identifier, clientState: ClientState, consensusState: ConsensusState) {
  assert(clientState.latestHeight > 0)
  assert(consensusState === nil)
  
  provableStore.set("clients/{identifier}/clientState", clientState)
}

function verifyClientMessage(clientMsg: ClientMessage) {
  assert(false)
}

function checkForMisbehaviour(clientMsg: clientMessage) => bool {
  return false
}

function updateState(clientMsg: clientMessage) {
  clientState = provableStore.get("clients/{clientMsg.identifier}/clientState")

  // retrieve the latest height from the local ledger
  height = getSelfHeight()
  clientState.latestHeight = height

  // save the client state
  provableStore.set("clients/{clientMsg.identifier}/clientState", clientState)
}

function updateStateOnMisbehaviour(clientMsg: clientMessage) { }

function verifyMembership(
  clientState: ClientState,
  height: Height,
  delayTimePeriod: uint64,
  delayBlockPeriod: uint64,
  proof: CommitmentProof,
  path: CommitmentPath,
  value: []byte
): Error {
  // path is prefixed with the store prefix of the commitment proof
  // e.g. in ibc-go implementation this is "ibc"
  // since verification is done on the IBC store of the local ledger
  // the prefix needs to be removed from the path to retrieve the
  // correct key in the store
  unprefixedPath = removePrefix(getCommitmentPrefix(), path)
  
  // The complete (not only client identifier-prefixed) store is needed
  // to verify that a path has been set to a particular value
  if provableStore.get(unprefixedPath) !== value {
    return error
  }
  return nil
}

function verifyNonMembership(
  clientState: ClientState,
  height: Height,
  delayTimePeriod: uint64,
  delayBlockPeriod: uint64,
  proof: CommitmentProof,
  path: CommitmentPath
): Error {
  // path is prefixed with the store prefix of the commitment proof
  // e.g. in ibc-go implementation this is "ibc"
  // since verification is done on the IBC store of the local ledger
  // the prefix needs to be removed from the path to retrieve the
  // correct key in the store
  unprefixedPath = removePrefix(getCommitmentPrefix(), path)

  // The complete (not only client identifier-prefixed) store is needed
  // to verify that a path has not been set to a particular value
  if provableStore.get(unprefixedPath) !== nil {
    return error
  }
  return nil
}