path: root/include/hotstuff/consensus.h

/**
 * Copyright 2018 VMware
 * Copyright 2018 Ted Yin
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef _HOTSTUFF_CONSENSUS_H
#define _HOTSTUFF_CONSENSUS_H

#include <cassert>
#include <set>
#include <unordered_map>

#include "hotstuff/promise.hpp"
#include "hotstuff/type.h"
#include "hotstuff/entity.h"
#include "hotstuff/crypto.h"

namespace hotstuff {

struct Proposal;
struct Vote;
struct Finality;

/** Abstraction for HotStuff protocol state machine (without network implementation). */
class HotStuffCore {
    block_t b0;                                  /** the genesis block */
    /* === state variables === */
    /** block containing the QC for the highest block having one */
    std::pair<block_t, quorum_cert_bt> hqc;   /**< highest QC */
    block_t b_lock;                            /**< locked block */
    block_t b_exec;                            /**< last executed block */
    uint32_t vheight;          /**< height of the block last voted for */
    /* === auxilliary variables === */
    privkey_bt priv_key;            /**< private key for signing votes */
    std::set<block_t, BlockHeightCmp> tails;   /**< set of tail blocks */
    ReplicaConfig config;                   /**< replica configuration */
    /* === async event queues === */
    std::unordered_map<block_t, promise_t> qc_waiting;
    promise_t propose_waiting;
    promise_t receive_proposal_waiting;
    promise_t hqc_update_waiting;
    /* == feature switches == */
    /** always vote negatively, useful for some PaceMakers */
    bool vote_disabled;

    block_t get_delivered_blk(const