// Copyright (c) 2011 The Bitcoin developers
+// Copyright (c) 2011-2012 The PPCoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file license.txt or http://www.opensource.org/licenses/mit-license.php.
-#include "checkpoints.h"
-#include "uint256.h"
-#include "util.h"
-
#include <boost/assign/list_of.hpp> // for 'map_list_of()'
+#include <boost/foreach.hpp>
+
+#include "headers.h"
+#include "checkpoints.h"
namespace Checkpoints
{
- typedef std::map<int, uint256> MapCheckpoints;
+ typedef std::map<int, uint256> MapCheckpoints; // hardened checkpoints
+ //
+ // What makes a good checkpoint block?
+ // + Is surrounded by blocks with reasonable timestamps
+ // (no blocks before with a timestamp after, none after with
+ // timestamp before)
+ // + Contains no strange transactions
+ //
static MapCheckpoints mapCheckpoints =
boost::assign::map_list_of
- ( 11111, uint256("0x0000000069e244f73d78e8fd29ba2fd2ed618bd6fa2ee92559f542fdb26e7c1d"))
- ( 33333, uint256("0x000000002dd5588a74784eaa7ab0507a18ad16a236e7b1ce69f00d7ddfb5d0a6"))
- ( 68555, uint256("0x00000000001e1b4903550a0b96e9a9405c8a95f387162e4944e8d9fbe501cd6a"))
- ( 70567, uint256("0x00000000006a49b14bcf27462068f1264c961f11fa2e0eddd2be0791e1d4124a"))
- ( 74000, uint256("0x0000000000573993a3c9e41ce34471c079dcf5f52a0e824a81e7f953b8661a20"))
- (105000, uint256("0x00000000000291ce28027faea320c8d2b054b2e0fe44a773f3eefb151d6bdc97"))
- (118000, uint256("0x000000000000774a7f8a7a12dc906ddb9e17e75d684f15e00f8767f9e8f36553"))
- (134444, uint256("0x00000000000005b12ffd4cd315cd34ffd4a594f430ac814c91184a0d42d2b0fe"))
- (140700, uint256("0x000000000000033b512028abb90e1626d8b346fd0ed598ac0a3c371138dce2bd"))
- ;
-
- bool CheckBlock(int nHeight, const uint256& hash)
+ ( 0, hashGenesisBlock )
+ ; // ppcoin: no checkpoint yet; to be created in future releases
+
+ // ppcoin: automatic checkpoint (represented by height of checkpoint)
+ int nAutoCheckpoint = 0;
+ int nBranchPoint = 0; // branch point to alternative branch
+
+ bool CheckHardened(int nHeight, const uint256& hash)
{
if (fTestNet) return true; // Testnet has no checkpoints
return hash == i->second;
}
+ // ppcoin: check automatic checkpoint
+ // To pass the check:
+ // - All ancestors (including the block itself) have block index already
+ // - The immediate ancestor in main chain must not have height less than
+ // checkpoint height
+ bool CheckAuto(const CBlockIndex *pindex)
+ {
+ while (pindex)
+ {
+ if (pindex->IsInMainChain())
+ {
+ if (pindex->nHeight >= nAutoCheckpoint)
+ return true;
+ else
+ {
+ nBranchPoint = pindex->nHeight;
+ return error("Checkpoints: new block on alternative branch at height=%d before auto checkpoint at height=%d", pindex->nHeight, nAutoCheckpoint);
+ }
+ }
+ else
+ pindex = pindex->pprev;
+ }
+ return error("Checkpoints: failed to find any ancestor on main chain for the new block - internal error");
+ }
+
+ // ppcoin: get next chain checkpoint
+ int GetNextChainCheckpoint(const CBlockIndex *pindexLast)
+ {
+ CBigNum bnTarget;
+ CBigNum bnTargetMax = 0; // max target of all blocks since checkpoint
+ CBigNum bnTargetMin = 0; // min target of all candidate checkpoints
+ int nMinTargetHeight = 0; // min target height of candidate checkpoints
+ int nCheckpointMin = 0; // minimum candidate checkpoint
+ int nCheckpointMax = 0; // maximum candidate checkpoint
+ int nDepth = pindexLast->nHeight - pindexLast->nCheckpoint;
+ const CBlockIndex *pindex = pindexLast;
+ while (nDepth >= 0 && pindex)
+ {
+ bnTarget.SetCompact(pindex->nBits);
+ if (bnTarget > bnTargetMax)
+ bnTargetMax = bnTarget;
+ if (nCheckpointMax > 0 && bnTarget < bnTargetMin)
+ {
+ bnTargetMin = bnTarget;
+ nMinTargetHeight = pindex->nHeight;
+ }
+ if (nCheckpointMax == 0 && pindexLast->GetBlockTime() - pindex->GetBlockTime() > AUTO_CHECKPOINT_MIN_SPAN)
+ {
+ nCheckpointMax = pindex->nHeight;
+ bnTargetMin.SetCompact(pindex->nBits);
+ nMinTargetHeight = pindex->nHeight;
+ }
+ if (pindexLast->GetBlockTime() - pindex->GetBlockTime() < AUTO_CHECKPOINT_MAX_SPAN)
+ nCheckpointMin = pindex->nHeight;
+ pindex = pindex->pprev;
+ nDepth--;
+ }
+
+ assert (nDepth == -1); // arrive at chain checkpoint now
+
+ printf("Checkpoints: min=%d max=%d tminheight=%d tmin=0x%08x tmax=0x%08x\n",
+ nCheckpointMin, nCheckpointMax, nMinTargetHeight,
+ bnTargetMin.GetCompact(), bnTargetMax.GetCompact());
+ if (nCheckpointMax == 0) // checkpoint stays if max candidate not found
+ return pindexLast->nCheckpoint;
+
+ if (bnTargetMin * 100 > bnTargetMax * 90)
+ return nCheckpointMax;
+ if (bnTarget * 100 > bnTargetMax * 90)
+ return nMinTargetHeight;
+ else
+ return nCheckpointMin;
+ }
+
+ // ppcoin: get next auto checkpoint from the new chain checkpoint
+ int GetNextAutoCheckpoint(int nCheckpoint)
+ {
+ return (std::max(nAutoCheckpoint, nCheckpoint));
+ }
+
+ // ppcoin: advance to next automatic checkpoint
+ void AdvanceAutoCheckpoint(int nCheckpoint)
+ {
+ nAutoCheckpoint = GetNextAutoCheckpoint(nCheckpoint);
+ printf("Checkpoints: auto checkpoint now at height=%d\n", nAutoCheckpoint);
+ }
+
int GetTotalBlocksEstimate()
{
- if (fTestNet) return 0; // Testnet has no checkpoints
+ if (fTestNet) return 0;
return mapCheckpoints.rbegin()->first;
}
+
+ // ppcoin: reset auto checkpoint
+ bool ResetAutoCheckpoint(int nCheckpoint)
+ {
+ if (nCheckpoint <= 0 || nCheckpoint > nBestHeight)
+ return error("ResetAutoCheckpoint() : new checkpoint invalid");
+ if (nCheckpoint >= nAutoCheckpoint)
+ return error("ResetAutoCheckpoint() : new checkpoint not earlier than current auto checkpoint");
+ CTxDB txdb;
+ txdb.TxnBegin();
+ if (!txdb.WriteAutoCheckpoint(nCheckpoint, true))
+ return error("ResetAutoCheckpoint() : database write failed");
+ if (!txdb.TxnCommit())
+ return error("ResetAutoCheckpoint() : database commit failed");
+ nAutoCheckpoint = nCheckpoint;
+ nBranchPoint = 0; // clear branch point
+
+ // clear ban list to accept alternative branches
+ CRITICAL_BLOCK(cs_vNodes)
+ {
+ BOOST_FOREACH(CNode* pnode, vNodes)
+ pnode->ClearBanned();
+ }
+
+ return true;
+ }
+
+ CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
+ {
+ if (fTestNet) return NULL;
+
+ int64 nResult;
+ BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
+ {
+ const uint256& hash = i.second;
+ std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hash);
+ if (t != mapBlockIndex.end())
+ return t->second;
+ }
+ return NULL;
+ }
}
git://git.novaco.in / novacoin.git / blobdiff