Method valid_external

mlspp/src/state.cpp:1893–1933

}

bool
// NOLINTNEXTLINE(readability-convert-member-functions-to-static)
State::valid_external(const std::vector<CachedProposal>& proposals) const
{
  // Exactly one ExternalInit
  auto ext_init_count = stdx::count_if(proposals, [](const auto& cached) {
    return cached.proposal.proposal_type() == ProposalType::external_init;
  });
  auto one_ext_init = (ext_init_count == 1);

  // At most one Remove proposal, with which the joiner removes an old version
  // of themselves. If a Remove proposal is present, then the LeafNode in the
  // path field of the external commit MUST meet the same criteria as would the
  // LeafNode in an Update for the removed leaf (see Section 12.1.2). In
  // particular, the credential in the LeafNode MUST present a set of
  // identifiers that is acceptable to the application for the removed
  // participant.
  // TODO(RLB) Verify that Remove is properly formed
  auto remove_count = stdx::count_if(proposals, [](const auto& cached) {
    return cached.proposal.proposal_type() == ProposalType::remove;
  });
  auto no_dup_remove = (remove_count <= 1);

  // Zero or more PreSharedKey proposals.
  // No other proposals.
  auto no_disallowed = stdx::all_of(proposals, [&](const auto& cached) {
    switch (cached.proposal.proposal_type()) {
      case ProposalType::external_init:
      case ProposalType::remove:
        return true;

      case ProposalType::psk:
        return valid(var::get<PreSharedKey>(cached.proposal.content));

      default:
        return false;
    }
  });

  return one_ext_init && no_dup_remove && no_disallowed;
}

State::CommitParams
State::infer_commit_type(