// Copyright (c) 2014-2020, The Monero Project
//
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#pragma once
#include "syncobj.h"
#include "hardforks/hardforks.h"
#include "cryptonote_basic/cryptonote_basic.h"
namespace cryptonote
{
class BlockchainDB;
class HardFork
{
public:
typedef enum {
LikelyForked,
UpdateNeeded,
Ready,
} State;
static const uint64_t DEFAULT_ORIGINAL_VERSION_TILL_HEIGHT = 0; // <= actual height
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 = 10080; // supermajority window check length - a week
static const uint8_t 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 default_threshold_percent the size of the majority in percents
*/
HardFork(cryptonote::BlockchainDB &db, uint8_t original_version = 1, uint64_t original_version_till_height = DEFAULT_ORIGINAL_VERSION_TILL_HEIGHT, time_t forked_time = DEFAULT_FORKED_TIME, time_t update_time = DEFAULT_UPDATE_TIME, uint64_t window_size = DEFAULT_WINDOW_SIZE, uint8_t default_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 threshold The threshold of votes needed for this fork (0-100)
* @param time Approximate time of the hardfork (seconds since epoch)
*/
bool add_fork(uint8_t version, uint64_t height, uint8_t threshold, time_t time);
/**
* @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_fork(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 same as check, but for a particular height, rather than the top
*
* NOTE: this does not play well with voting, and relies on voting to be
* disabled (that is, forks happen on the scheduled date, whether or not
* enough blocks have voted for the fork).
*
* returns true if no error, false otherwise
*
* @param block the new block
* @param height which height to check for
*/
bool check_for_height(const cryptonote::block &block, uint64_t height) 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 called when one or more blocks are popped from the blockchain
*
* The current fork will be updated by looking up the db,
* which is much cheaper than recomputing everything
*
* @param new_chain_height the height of the chain after popping
*/
void on_block_popped(uint64_t new_chain_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 latest "ideal" version
*
* This is the latest version that's been scheduled
*/
uint8_t get_ideal_version() const;
/**
* @brief returns the "ideal" version for a given height
*
* @param height height of the block to check
*/
uint8_t get_ideal_version(uint64_t height) const;
/**
* @brief returns the next version
*
* This is the version which will we fork to next
*/
uint8_t get_next_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 the earliest block a given version may activate
*/
uint64_t get_earliest_ideal_height_for_version(uint8_t 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
* @param earliest_height earliest height at which the version can take effect
*/
bool get_voting_info(uint8_t version, uint32_t &window, uint32_t &votes, uint32_t &threshold, uint64_t &earliest_height, uint8_t &voting) const;
/**
* @brief returns the size of the voting window in blocks
*/
uint64_t get_window_size() const { return window_size; }
private:
uint8_t get_block_version(uint64_t height) const;
bool do_check(uint8_t block_version, uint8_t voting_version) const;
bool do_check_for_height(uint8_t block_version, uint8_t voting_version, uint64_t height) const;
int get_voted_fork_index(uint64_t height) const;
uint8_t get_effective_version(uint8_t voting_version) const;
bool add(uint8_t block_version, uint8_t voting_version, uint64_t height);
bool rescan_from_block_height(uint64_t height);
bool rescan_from_chain_height(uint64_t height);
private:
BlockchainDB &db;
time_t forked_time;
time_t update_time;
uint64_t window_size;
uint8_t default_threshold_percent;
uint8_t original_version;
uint64_t original_version_till_height;
std::vector<hardfork_t> 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;
mutable epee::critical_section lock;
};
} // namespace cryptonote
