monero/src/cryptonote_core/checkpoints.cpp

// Copyright (c) 2014-2016, The Monero Project
// 
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//    conditions and the following disclaimer.
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// 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
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//    prior written permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers

#include "include_base_utils.h"
using namespace epee;

#include "checkpoints.h"

namespace cryptonote
{
  //---------------------------------------------------------------------------
  checkpoints::checkpoints()
  {
  }
  //---------------------------------------------------------------------------
  bool checkpoints::add_checkpoint(uint64_t height, const std::string& hash_str)
  {
    crypto::hash h = null_hash;
    bool r = epee::string_tools::parse_tpod_from_hex_string(hash_str, h);
    CHECK_AND_ASSERT_MES(r, false, "Failed to parse checkpoint hash string into binary representation!");

    // return false if adding at a height we already have AND the hash is different
    if (m_points.count(height))
    {
      CHECK_AND_ASSERT_MES(h == m_points[height], false, "Checkpoint at given height already exists, and hash for new checkpoint was different!");
    }
    m_points[height] = h;
    return true;
  }
  //---------------------------------------------------------------------------
  bool checkpoints::is_in_checkpoint_zone(uint64_t height) const
  {
    return !m_points.empty() && (height <= (--m_points.end())->first);
  }
  //---------------------------------------------------------------------------
  bool checkpoints::check_block(uint64_t height, const crypto::hash& h, bool& is_a_checkpoint) const
  {
    auto it = m_points.find(height);
    is_a_checkpoint = it != m_points.end();
    if(!is_a_checkpoint)
      return true;

    if(it->second == h)
    {
      LOG_PRINT_GREEN("CHECKPOINT PASSED FOR HEIGHT " << height << " " << h, LOG_LEVEL_1);
      return true;
    }else
    {
      LOG_ERROR("CHECKPOINT FAILED FOR HEIGHT " << height << ". EXPECTED HASH: " << it->second << ", FETCHED HASH: " << h);
      return false;
    }
  }
  //---------------------------------------------------------------------------
  bool checkpoints::check_block(uint64_t height, const crypto::hash& h) const
  {
    bool ignored;
    return check_block(height, h, ignored);
  }
  //---------------------------------------------------------------------------
  // 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.
  bool checkpoints::is_alternative_block_allowed(uint64_t blockchain_height, uint64_t block_height) const
  {
    if (0 == block_height)
      return false;

    auto it = m_points.upper_bound(blockchain_height);
    // Is blockchain_height before the first checkpoint?
    if (it == m_points.begin())
      return true;

    --it;
    uint64_t checkpoint_height = it->first;
    return checkpoint_height < block_height;
  }
  //---------------------------------------------------------------------------
  uint64_t checkpoints::get_max_height() const
  {
    std::map< uint64_t, crypto::hash >::const_iterator highest = 
        std::max_element( m_points.begin(), m_points.end(),
                         ( boost::bind(&std::map< uint64_t, crypto::hash >::value_type::first, _1) < 
                           boost::bind(&std::map< uint64_t, crypto::hash >::value_type::first, _2 ) ) );
    return highest->first;
  }
  //---------------------------------------------------------------------------
  const std::map<uint64_t, crypto::hash>& checkpoints::get_points() const
  {
    return m_points;
  }

  bool checkpoints::check_for_conflicts(const checkpoints& other) const
  {
    for (auto& pt : other.get_points())
    {
      if (m_points.count(pt.first))
      {
        CHECK_AND_ASSERT_MES(pt.second == m_points.at(pt.first), false, "Checkpoint at given height already exists, and hash for new checkpoint was different!");
      }
    }
    return true;
  }
}