// Copyright (c) 2014-2017, The Monero Project
//
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// permitted provided that the following conditions are met:
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// 2. Redistributions in binary form must reproduce the above copyright notice, this list
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// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
#pragma once
#include <map>
#include <vector>
#include "misc_log_ex.h"
#include "crypto/hash.h"
#define ADD_CHECKPOINT(h, hash) CHECK_AND_ASSERT(add_checkpoint(h, hash), false);
#define JSON_HASH_FILE_NAME "checkpoints.json"
namespace cryptonote
{
/**
* @brief A container for blockchain checkpoints
*
* A checkpoint is a pre-defined hash for the block at a given height.
* Some of these are compiled-in, while others can be loaded at runtime
* either from a json file or via DNS from a checkpoint-hosting server.
*/
class checkpoints
{
public:
/**
* @brief default constructor
*/
checkpoints();
/**
* @brief adds a checkpoint to the container
*
* @param height the height of the block the checkpoint is for
* @param hash_str the hash of the block, as a string
*
* @return false if parsing the hash fails, or if the height is a duplicate
* AND the existing checkpoint hash does not match the new one,
* otherwise returns true
*/
bool add_checkpoint(uint64_t height, const std::string& hash_str);
/**
* @brief checks if there is a checkpoint in the future
*
* This function checks if the height passed is lower than the highest
* checkpoint.
*
* @param height the height to check against
*
* @return false if no checkpoints, otherwise returns whether or not
* the height passed is lower than the highest checkpoint.
*/
bool is_in_checkpoint_zone(uint64_t height) const;
/**
* @brief checks if the given height and hash agree with the checkpoints
*
* This function checks if the given height and hash exist in the
* checkpoints container. If so, it returns whether or not the passed
* parameters match the stored values.
*
* @param height the height to be checked
* @param h the hash to be checked
* @param is_a_checkpoint return-by-reference if there is a checkpoint at the given height
*
* @return true if there is no checkpoint at the given height,
* true if the passed parameters match the stored checkpoint,
* false otherwise
*/
bool check_block(uint64_t height, const crypto::hash& h, bool& is_a_checkpoint) const;
/**
* @overload
*/
bool check_block(uint64_t height, const crypto::hash& h) const;
/**
* @brief checks if alternate chain blocks should be kept for a given height
*
* this basically says if the blockchain is smaller than the first
* checkpoint then alternate blocks are allowed. Alternatively, if the
* last checkpoint *before* the end of the current chain is also before
* the block to be added, then this is fine.
*
* @param blockchain_height the current blockchain height
* @param block_height the height of the block to be added as alternate
*
* @return true if alternate blocks are allowed given the parameters,
* otherwise false
*/
bool is_alternative_block_allowed(uint64_t blockchain_height, uint64_t block_height) const;
/**
* @brief gets the highest checkpoint height
*
* @return the height of the highest checkpoint
*/
uint64_t get_max_height() const;
/**
* @brief gets the checkpoints container
*
* @return a const reference to the checkpoints container
*/
const std::map<uint64_t, crypto::hash>& get_points() const;
/**
* @brief checks if our checkpoints container conflicts with another
*
* A conflict refers to a case where both checkpoint sets have a checkpoint
* for a specific height but their hashes for that height do not match.
*
* @param other the other checkpoints instance to check against
*
* @return false if any conflict is found, otherwise true
*/
bool check_for_conflicts(const checkpoints& other) const;
/**
* @brief loads the default main chain checkpoints
* @param testnet whether to load testnet checkpoints or mainnet
*
* @return true unless adding a checkpoint fails
*/
bool init_default_checkpoints(bool testnet);
/**
* @brief load new checkpoints
*
* Loads new checkpoints from the specified json file, as well as
* (optionally) from DNS.
*
* @param json_hashfile_fullpath path to the json checkpoints file
* @param testnet whether to load testnet checkpoints or mainnet
* @param dns whether or not to load DNS checkpoints
*
* @return true if loading successful and no conflicts
*/
bool load_new_checkpoints(const std::string &json_hashfile_fullpath, bool testnet=false, bool dns=true);
/**
* @brief load new checkpoints from json
*
* @param json_hashfile_fullpath path to the json checkpoints file
*
* @return true if loading successful and no conflicts
*/
bool load_checkpoints_from_json(const std::string &json_hashfile_fullpath);
/**
* @brief load new checkpoints from DNS
*
* @param testnet whether to load testnet checkpoints or mainnet
*
* @return true if loading successful and no conflicts
*/
bool load_checkpoints_from_dns(bool testnet = false);
private:
std::map<uint64_t, crypto::hash> m_points; //!< the checkpoints container
};
}
