Make CCoinsView use block hashes instead of indices

src/main.cpp

@@ -236,9 +236,9 @@ CBlockIndex *CChain::FindFork(const CBlockLocator &locator) const {
 bool CCoinsView::GetCoins(const uint256 &txid, CCoins &coins) { return false; }
 bool CCoinsView::SetCoins(const uint256 &txid, const CCoins &coins) { return false; }
 bool CCoinsView::HaveCoins(const uint256 &txid) { return false; }
-CBlockIndex *CCoinsView::GetBestBlock() { return NULL; }
-bool CCoinsView::SetBestBlock(CBlockIndex *pindex) { return false; }
-bool CCoinsView::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return false; }
+uint256 CCoinsView::GetBestBlock() { return uint256(0); }
+bool CCoinsView::SetBestBlock(const uint256 &hashBlock) { return false; }
+bool CCoinsView::BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock) { return false; }
 bool CCoinsView::GetStats(CCoinsStats &stats) { return false; }
 
 
@@ -246,13 +246,13 @@ CCoinsViewBacked::CCoinsViewBacked(CCoinsView &viewIn) : base(&viewIn) { }
 bool CCoinsViewBacked::GetCoins(const uint256 &txid, CCoins &coins) { return base->GetCoins(txid, coins); }
 bool CCoinsViewBacked::SetCoins(const uint256 &txid, const CCoins &coins) { return base->SetCoins(txid, coins); }
 bool CCoinsViewBacked::HaveCoins(const uint256 &txid) { return base->HaveCoins(txid); }
-CBlockIndex *CCoinsViewBacked::GetBestBlock() { return base->GetBestBlock(); }
-bool CCoinsViewBacked::SetBestBlock(CBlockIndex *pindex) { return base->SetBestBlock(pindex); }
+uint256 CCoinsViewBacked::GetBestBlock() { return base->GetBestBlock(); }
+bool CCoinsViewBacked::SetBestBlock(const uint256 &hashBlock) { return base->SetBestBlock(hashBlock); }
 void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) { base = &viewIn; }
-bool CCoinsViewBacked::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return base->BatchWrite(mapCoins, pindex); }
+bool CCoinsViewBacked::BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock) { return base->BatchWrite(mapCoins, hashBlock); }
 bool CCoinsViewBacked::GetStats(CCoinsStats &stats) { return base->GetStats(stats); }
 
-CCoinsViewCache::CCoinsViewCache(CCoinsView &baseIn, bool fDummy) : CCoinsViewBacked(baseIn), pindexTip(NULL) { }
+CCoinsViewCache::CCoinsViewCache(CCoinsView &baseIn, bool fDummy) : CCoinsViewBacked(baseIn), hashBlock(0) { }
 
 bool CCoinsViewCache::GetCoins(const uint256 &txid, CCoins &coins) {
     if (cacheCoins.count(txid)) {
@@ -293,26 +293,26 @@ bool CCoinsViewCache::HaveCoins(const uint256 &txid) {
     return FetchCoins(txid) != cacheCoins.end();
 }
 
-CBlockIndex *CCoinsViewCache::GetBestBlock() {
-    if (pindexTip == NULL)
-        pindexTip = base->GetBestBlock();
-    return pindexTip;
+uint256 CCoinsViewCache::GetBestBlock() {
+    if (hashBlock == uint256(0))
+        hashBlock = base->GetBestBlock();
+    return hashBlock;
 }
 
-bool CCoinsViewCache::SetBestBlock(CBlockIndex *pindex) {
-    pindexTip = pindex;
+bool CCoinsViewCache::SetBestBlock(const uint256 &hashBlockIn) {
+    hashBlock = hashBlockIn;
     return true;
 }
 
-bool CCoinsViewCache::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) {
+bool CCoinsViewCache::BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlockIn) {
     for (std::map<uint256, CCoins>::const_iterator it = mapCoins.begin(); it != mapCoins.end(); it++)
         cacheCoins[it->first] = it->second;
-    pindexTip = pindex;
+    hashBlock = hashBlockIn;
     return true;
 }
 
 bool CCoinsViewCache::Flush() {
-    bool fOk = base->BatchWrite(cacheCoins, pindexTip);
+    bool fOk = base->BatchWrite(cacheCoins, hashBlock);
     if (fOk)
         cacheCoins.clear();
     return fOk;
@@ -1498,7 +1498,8 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, CCoinsViewCach
 
         // While checking, GetBestBlock() refers to the parent block.
         // This is also true for mempool checks.
-        int nSpendHeight = inputs.GetBestBlock()->nHeight + 1;
+        CBlockIndex *pindexPrev = mapBlockIndex.find(inputs.GetBestBlock())->second;
+        int nSpendHeight = pindexPrev->nHeight + 1;
         int64_t nValueIn = 0;
         int64_t nFees = 0;
         for (unsigned int i = 0; i < tx.vin.size(); i++)
@@ -1568,7 +1569,7 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, CCoinsViewCach
 
 bool DisconnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& view, bool* pfClean)
 {
-    assert(pindex == view.GetBestBlock());
+    assert(pindex->GetBlockHash() == view.GetBestBlock());
 
     if (pfClean)
         *pfClean = false;
@@ -1644,7 +1645,7 @@ bool DisconnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex
     }
 
     // move best block pointer to prevout block
-    view.SetBestBlock(pindex->pprev);
+    view.SetBestBlock(pindex->pprev->GetBlockHash());
 
     if (pfClean) {
         *pfClean = fClean;
@@ -1693,12 +1694,13 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
         return false;
 
     // verify that the view's current state corresponds to the previous block
-    assert(pindex->pprev == view.GetBestBlock());
+    uint256 hashPrevBlock = pindex->pprev == NULL ? uint256(0) : pindex->pprev->GetBlockHash();
+    assert(hashPrevBlock == view.GetBestBlock());
 
     // Special case for the genesis block, skipping connection of its transactions
     // (its coinbase is unspendable)
     if (block.GetHash() == Params().HashGenesisBlock()) {
-        view.SetBestBlock(pindex);
+        view.SetBestBlock(pindex->GetBlockHash());
         return true;
     }
 
@@ -1828,7 +1830,7 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
             return state.Abort(_("Failed to write transaction index"));
 
     // add this block to the view's block chain
-    assert(view.SetBestBlock(pindex));
+    assert(view.SetBestBlock(pindex->GetBlockHash()));
 
     // Watch for transactions paying to me
     for (unsigned int i = 0; i < block.vtx.size(); i++)
@@ -1846,7 +1848,9 @@ bool SetBestChain(CValidationState &state, CBlockIndex* pindexNew)
     CCoinsViewCache view(*pcoinsTip, true);
 
     // Find the fork (typically, there is none)
-    CBlockIndex* pfork = view.GetBestBlock();
+    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(view.GetBestBlock());
+    CBlockIndex* ptip = (it != mapBlockIndex.end()) ? it->second : NULL;
+    CBlockIndex* pfork = ptip;
     CBlockIndex* plonger = pindexNew;
     while (pfork && pfork != plonger)
     {
@@ -1862,7 +1866,7 @@ bool SetBestChain(CValidationState &state, CBlockIndex* pindexNew)
 
     // List of what to disconnect (typically nothing)
     vector<CBlockIndex*> vDisconnect;
-    for (CBlockIndex* pindex = view.GetBestBlock(); pindex != pfork; pindex = pindex->pprev)
+    for (CBlockIndex* pindex = ptip; pindex != pfork; pindex = pindex->pprev)
         vDisconnect.push_back(pindex);
 
     // List of what to connect (typically only pindexNew)
@@ -2687,9 +2691,10 @@ bool static LoadBlockIndexDB()
     LogPrintf("LoadBlockIndexDB(): transaction index %s\n", fTxIndex ? "enabled" : "disabled");
 
     // Load pointer to end of best chain
-    chainActive.SetTip(pcoinsTip->GetBestBlock());
-    if (chainActive.Tip() == NULL)
+    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
+    if (it == mapBlockIndex.end())
         return true;
+    chainActive.SetTip(it->second);
     LogPrintf("LoadBlockIndexDB(): hashBestChain=%s  height=%d date=%s\n",
         chainActive.Tip()->GetBlockHash().ToString().c_str(), chainActive.Height(),
         DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()).c_str());

src/main.h

@@ -1062,14 +1062,14 @@ public:
     // This may (but cannot always) return true for fully spent transactions
     virtual bool HaveCoins(const uint256 &txid);
 
-    // Retrieve the block index whose state this CCoinsView currently represents
-    virtual CBlockIndex *GetBestBlock();
+    // Retrieve the block hash whose state this CCoinsView currently represents
+    virtual uint256 GetBestBlock();
 
-    // Modify the currently active block index
-    virtual bool SetBestBlock(CBlockIndex *pindex);
+    // Modify the currently active block hash
+    virtual bool SetBestBlock(const uint256 &hashBlock);
 
     // Do a bulk modification (multiple SetCoins + one SetBestBlock)
-    virtual bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex);
+    virtual bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock);
 
     // Calculate statistics about the unspent transaction output set
     virtual bool GetStats(CCoinsStats &stats);
@@ -1089,10 +1089,10 @@ public:
     bool GetCoins(const uint256 &txid, CCoins &coins);
     bool SetCoins(const uint256 &txid, const CCoins &coins);
     bool HaveCoins(const uint256 &txid);
-    CBlockIndex *GetBestBlock();
-    bool SetBestBlock(CBlockIndex *pindex);
+    uint256 GetBestBlock();
+    bool SetBestBlock(const uint256 &hashBlock);
     void SetBackend(CCoinsView &viewIn);
-    bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex);
+    bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock);
     bool GetStats(CCoinsStats &stats);
 };
 
@@ -1100,7 +1100,7 @@ public:
 class CCoinsViewCache : public CCoinsViewBacked
 {
 protected:
-    CBlockIndex *pindexTip;
+    uint256 hashBlock;
     std::map<uint256,CCoins> cacheCoins;
 
 public:
@@ -1110,9 +1110,9 @@ public:
     bool GetCoins(const uint256 &txid, CCoins &coins);
     bool SetCoins(const uint256 &txid, const CCoins &coins);
     bool HaveCoins(const uint256 &txid);
-    CBlockIndex *GetBestBlock();
-    bool SetBestBlock(CBlockIndex *pindex);
-    bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex);
+    uint256 GetBestBlock();
+    bool SetBestBlock(const uint256 &hashBlock);
+    bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock);
 
     // Return a modifiable reference to a CCoins. Check HaveCoins first.
     // Many methods explicitly require a CCoinsViewCache because of this method, to reduce

src/rpcblockchain.cpp

@@ -245,11 +245,13 @@ Value gettxout(const Array& params, bool fHelp)
     if (n<0 || (unsigned int)n>=coins.vout.size() || coins.vout[n].IsNull())
         return Value::null;
 
-    ret.push_back(Pair("bestblock", pcoinsTip->GetBestBlock()->GetBlockHash().GetHex()));
+    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
+    CBlockIndex *pindex = it->second;
+    ret.push_back(Pair("bestblock", pindex->GetBlockHash().GetHex()));
     if ((unsigned int)coins.nHeight == MEMPOOL_HEIGHT)
         ret.push_back(Pair("confirmations", 0));
     else
-        ret.push_back(Pair("confirmations", pcoinsTip->GetBestBlock()->nHeight - coins.nHeight + 1));
+        ret.push_back(Pair("confirmations", pindex->nHeight - coins.nHeight + 1));
     ret.push_back(Pair("value", ValueFromAmount(coins.vout[n].nValue)));
     Object o;
     ScriptPubKeyToJSON(coins.vout[n].scriptPubKey, o, true);

src/txdb.cpp

@@ -40,30 +40,27 @@ bool CCoinsViewDB::HaveCoins(const uint256 &txid) {
     return db.Exists(make_pair('c', txid)); 
 }
 
-CBlockIndex *CCoinsViewDB::GetBestBlock() {
+uint256 CCoinsViewDB::GetBestBlock() {
     uint256 hashBestChain;
     if (!db.Read('B', hashBestChain))
-        return NULL;
-    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(hashBestChain);
-    if (it == mapBlockIndex.end())
-        return NULL;
-    return it->second;
+        return uint256(0);
+    return hashBestChain;
 }
 
-bool CCoinsViewDB::SetBestBlock(CBlockIndex *pindex) {
+bool CCoinsViewDB::SetBestBlock(const uint256 &hashBlock) {
     CLevelDBBatch batch;
-    BatchWriteHashBestChain(batch, pindex->GetBlockHash()); 
+    BatchWriteHashBestChain(batch, hashBlock);
     return db.WriteBatch(batch);
 }
 
-bool CCoinsViewDB::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) {
+bool CCoinsViewDB::BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock) {
     LogPrint("coindb", "Committing %u changed transactions to coin database...\n", (unsigned int)mapCoins.size());
 
     CLevelDBBatch batch;
     for (std::map<uint256, CCoins>::const_iterator it = mapCoins.begin(); it != mapCoins.end(); it++)
         BatchWriteCoins(batch, it->first, it->second);
-    if (pindex)
-        BatchWriteHashBestChain(batch, pindex->GetBlockHash());
+    if (hashBlock != uint256(0))
+        BatchWriteHashBestChain(batch, hashBlock);
 
     return db.WriteBatch(batch);
 }
@@ -115,7 +112,7 @@ bool CCoinsViewDB::GetStats(CCoinsStats &stats) {
     pcursor->SeekToFirst();
 
     CHashWriter ss(SER_GETHASH, PROTOCOL_VERSION);
-    stats.hashBlock = GetBestBlock()->GetBlockHash();
+    stats.hashBlock = GetBestBlock();
     ss << stats.hashBlock;
     int64_t nTotalAmount = 0;
     while (pcursor->Valid()) {
@@ -155,7 +152,7 @@ bool CCoinsViewDB::GetStats(CCoinsStats &stats) {
         }
     }
     delete pcursor;
-    stats.nHeight = GetBestBlock()->nHeight;
+    stats.nHeight = mapBlockIndex.find(GetBestBlock())->second->nHeight;
     stats.hashSerialized = ss.GetHash();
     stats.nTotalAmount = nTotalAmount;
     return true;

src/txdb.h

@@ -29,9 +29,9 @@ public:
     bool GetCoins(const uint256 &txid, CCoins &coins);
     bool SetCoins(const uint256 &txid, const CCoins &coins);
     bool HaveCoins(const uint256 &txid);
-    CBlockIndex *GetBestBlock();
-    bool SetBestBlock(CBlockIndex *pindex);
-    bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex);
+    uint256 GetBestBlock();
+    bool SetBestBlock(const uint256 &hashBlock);
+    bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock);
     bool GetStats(CCoinsStats &stats);
 };