// Copyright (c) 2015, The Monero Project
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#pragma once
#include "syncobj.h"
#include "cryptonote_core/cryptonote_basic.h"
namespace cryptonote
{
class BlockchainDB;
class HardFork
{
public:
typedef enum {
LikelyForked,
UpdateNeeded,
Ready,
} State;
static const time_t DEFAULT_FORKED_TIME = 31557600; // a year in seconds
static const time_t DEFAULT_UPDATE_TIME = 31557600 / 2;
static const uint64_t DEFAULT_WINDOW_SIZE = 50; // supermajority window check length
static const int DEFAULT_THRESHOLD_PERCENT = 80;
/**
* @brief creates a new HardFork object
*
* @param original_version the block version for blocks 0 through to the first fork
* @param forked_time the time in seconds before thinking we're forked
* @param update_time the time in seconds before thinking we need to update
* @param window_size the size of the window in blocks to consider for version voting
* @param threshold_percent the size of the majority in percents
*/
HardFork(cryptonote::BlockchainDB &db, uint8_t original_version = 1, time_t forked_time = DEFAULT_FORKED_TIME, time_t update_time = DEFAULT_UPDATE_TIME, uint64_t window_size = DEFAULT_WINDOW_SIZE, int threshold_percent = DEFAULT_THRESHOLD_PERCENT);
/**
* @brief add a new hardfork height
*
* returns true if no error, false otherwise
*
* @param version the major block version for the fork
* @param height The height the hardfork takes effect
* @param time Approximate time of the hardfork (seconds since epoch)
*/
bool add(uint8_t version, uint64_t height, time_t time);
/**
* @brief initialize the object
*
* Must be done after adding all the required hardforks via add above
*/
void init();
/**
* @brief check whether a new block would be accepted
*
* returns true if the block is accepted, false otherwise
*
* @param block the new block
*
* This check is made by add. It is exposed publicly to allow
* the caller to inexpensively check whether a block would be
* accepted or rejected by its version number. Indeed, if this
* check could only be done as part of add, the caller would
* either have to add the block to the blockchain first, then
* call add, then have to pop the block from the blockchain if
* its version did not satisfy the hard fork requirements, or
* call add first, then, if the hard fork requirements are met,
* add the block to the blockchain, upon which a failure (the
* block being invalid, double spending, etc) would cause the
* hardfork object to reorganize.
*/
bool check(const cryptonote::block &block) const;
/**
* @brief add a new block
*
* returns true if no error, false otherwise
*
* @param block the new block
*/
bool add(const cryptonote::block &block, uint64_t height);
/**
* @brief called when the blockchain is reorganized
*
* This will rescan the blockchain to determine which hard forks
* have been triggered
*
* returns true if no error, false otherwise
*
* @param blockchain the blockchain
* @param height of the last block kept from the previous blockchain
*/
bool reorganize_from_block_height(uint64_t height);
bool reorganize_from_chain_height(uint64_t height);
/**
* @brief returns current state at the given time
*
* Based on the approximate time of the last known hard fork,
* estimate whether we need to update, or if we're way behind
*
* @param t the time to consider
*/
State get_state(time_t t) const;
State get_state() const;
/**
* @brief returns the hard fork version for the given block height
*
* @param height height of the block to check
*/
uint8_t get(uint64_t height) const;
/**
* @brief returns the height of the first block on the fork with th given version
*
* @param version version of the fork to query the starting block for
*/
uint64_t get_start_height(uint8_t version) const;
/**
* @brief returns the latest "ideal" version
*
* This is the latest version that's been scheduled
*/
uint8_t get_ideal_version() const;
/**
* @brief returns the current version
*
* This is the latest version that's past its trigger date and had enough votes
* at one point in the past.
*/
uint8_t get_current_version() const;
/**
* @brief returns information about current voting state
*
* returns true if the given version is enabled (ie, the current version
* is at least the passed version), false otherwise
*
* @param version the version to check voting for
* @param window the number of blocks considered in voting
* @param votes number of votes for next version
* @param threshold number of votes needed to switch to next version
*/
bool get_voting_info(uint8_t version, uint32_t &window, uint32_t &votes, uint32_t &threshold, uint8_t &voting) const;
/**
* @brief returns the size of the voting window in blocks
*/
uint64_t get_window_size() const { return window_size; }
private:
bool do_check(const cryptonote::block &block) const;
int get_voted_fork_index(uint64_t height) const;
uint8_t get_effective_version(const cryptonote::block &block) const;
private:
BlockchainDB &db;
time_t forked_time;
time_t update_time;
uint64_t window_size;
int threshold_percent;
uint8_t original_version;
typedef struct {
uint8_t version;
uint64_t height;
time_t time;
} Params;
std::vector<Params> heights;
std::deque<uint8_t> versions; /* rolling window of the last N blocks' versions */
unsigned int last_versions[256]; /* count of the block versions in the last N blocks */
uint32_t current_fork_index;
uint32_t vote_threshold;
mutable epee::critical_section lock;
};
} // namespace cryptonote
