@Override
 public VerificationException call() throws Exception {
   try {
     ListIterator<Script> prevOutIt = prevOutScripts.listIterator();
     for (int index = 0; index < tx.getInputs().size(); index++) {
       tx.getInputs()
           .get(index)
           .getScriptSig()
           .correctlySpends(tx, index, prevOutIt.next(), enforcePayToScriptHash);
     }
   } catch (VerificationException e) {
     return e;
   }
   return null;
 }
  @Override
  /** Used during reorgs to connect a block previously on a fork */
  protected synchronized TransactionOutputChanges connectTransactions(StoredBlock newBlock)
      throws VerificationException, BlockStoreException, PrunedException {
    checkState(lock.isHeldByCurrentThread());
    if (!params.passesCheckpoint(newBlock.getHeight(), newBlock.getHeader().getHash()))
      throw new VerificationException("Block failed checkpoint lockin at " + newBlock.getHeight());

    blockStore.beginDatabaseBatchWrite();
    StoredUndoableBlock block = blockStore.getUndoBlock(newBlock.getHeader().getHash());
    if (block == null) {
      // We're trying to re-org too deep and the data needed has been deleted.
      blockStore.abortDatabaseBatchWrite();
      throw new PrunedException(newBlock.getHeader().getHash());
    }
    TransactionOutputChanges txOutChanges;
    try {
      List<Transaction> transactions = block.getTransactions();
      if (transactions != null) {
        LinkedList<StoredTransactionOutput> txOutsSpent = new LinkedList<StoredTransactionOutput>();
        LinkedList<StoredTransactionOutput> txOutsCreated =
            new LinkedList<StoredTransactionOutput>();
        long sigOps = 0;
        final boolean enforcePayToScriptHash =
            newBlock.getHeader().getTimeSeconds() >= NetworkParameters.BIP16_ENFORCE_TIME;
        if (!params.isCheckpoint(newBlock.getHeight())) {
          for (Transaction tx : transactions) {
            Sha256Hash hash = tx.getHash();
            if (blockStore.hasUnspentOutputs(hash, tx.getOutputs().size()))
              throw new VerificationException("Block failed BIP30 test!");
          }
        }
        Coin totalFees = Coin.ZERO;
        Coin coinbaseValue = null;

        if (scriptVerificationExecutor.isShutdown())
          scriptVerificationExecutor =
              Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
        List<Future<VerificationException>> listScriptVerificationResults =
            new ArrayList<Future<VerificationException>>(transactions.size());
        for (final Transaction tx : transactions) {
          boolean isCoinBase = tx.isCoinBase();
          Coin valueIn = Coin.ZERO;
          Coin valueOut = Coin.ZERO;
          final List<Script> prevOutScripts = new LinkedList<Script>();
          if (!isCoinBase) {
            for (int index = 0; index < tx.getInputs().size(); index++) {
              final TransactionInput in = tx.getInputs().get(index);
              final StoredTransactionOutput prevOut =
                  blockStore.getTransactionOutput(
                      in.getOutpoint().getHash(), in.getOutpoint().getIndex());
              if (prevOut == null)
                throw new VerificationException(
                    "Attempted spend of a non-existent or already spent output!");
              if (newBlock.getHeight() - prevOut.getHeight() < params.getSpendableCoinbaseDepth())
                throw new VerificationException(
                    "Tried to spend coinbase at depth "
                        + (newBlock.getHeight() - prevOut.getHeight()));
              valueIn = valueIn.add(prevOut.getValue());
              if (enforcePayToScriptHash) {
                Script script = new Script(prevOut.getScriptBytes());
                if (script.isPayToScriptHash())
                  sigOps += Script.getP2SHSigOpCount(in.getScriptBytes());
                if (sigOps > Block.MAX_BLOCK_SIGOPS)
                  throw new VerificationException("Too many P2SH SigOps in block");
              }

              prevOutScripts.add(new Script(prevOut.getScriptBytes()));

              blockStore.removeUnspentTransactionOutput(prevOut);
              txOutsSpent.add(prevOut);
            }
          }
          Sha256Hash hash = tx.getHash();
          for (TransactionOutput out : tx.getOutputs()) {
            valueOut = valueOut.add(out.getValue());
            StoredTransactionOutput newOut =
                new StoredTransactionOutput(
                    hash,
                    out.getIndex(),
                    out.getValue(),
                    newBlock.getHeight(),
                    isCoinBase,
                    out.getScriptBytes());
            blockStore.addUnspentTransactionOutput(newOut);
            txOutsCreated.add(newOut);
          }
          // All values were already checked for being non-negative (as it is verified in
          // Transaction.verify())
          // but we check again here just for defence in depth. Transactions with zero output value
          // are OK.
          if (valueOut.signum() < 0 || valueOut.compareTo(NetworkParameters.MAX_MONEY) > 0)
            throw new VerificationException("Transaction output value out of range");
          if (isCoinBase) {
            coinbaseValue = valueOut;
          } else {
            if (valueIn.compareTo(valueOut) < 0
                || valueIn.compareTo(NetworkParameters.MAX_MONEY) > 0)
              throw new VerificationException("Transaction input value out of range");
            totalFees = totalFees.add(valueIn.subtract(valueOut));
          }

          if (!isCoinBase) {
            // Because correctlySpends modifies transactions, this must come after we are done with
            // tx
            FutureTask<VerificationException> future =
                new FutureTask<VerificationException>(
                    new Verifier(tx, prevOutScripts, enforcePayToScriptHash));
            scriptVerificationExecutor.execute(future);
            listScriptVerificationResults.add(future);
          }
        }
        if (totalFees.compareTo(NetworkParameters.MAX_MONEY) > 0
            || newBlock
                    .getHeader()
                    .getBlockInflation(newBlock.getHeight())
                    .add(totalFees)
                    .compareTo(coinbaseValue)
                < 0) throw new VerificationException("Transaction fees out of range");
        txOutChanges = new TransactionOutputChanges(txOutsCreated, txOutsSpent);
        for (Future<VerificationException> future : listScriptVerificationResults) {
          VerificationException e;
          try {
            e = future.get();
          } catch (InterruptedException thrownE) {
            throw new RuntimeException(thrownE); // Shouldn't happen
          } catch (ExecutionException thrownE) {
            log.error("Script.correctlySpends threw a non-normal exception: " + thrownE.getCause());
            throw new VerificationException(
                "Bug in Script.correctlySpends, likely script malformed in some new and interesting way.",
                thrownE);
          }
          if (e != null) throw e;
        }
      } else {
        txOutChanges = block.getTxOutChanges();
        if (!params.isCheckpoint(newBlock.getHeight()))
          for (StoredTransactionOutput out : txOutChanges.txOutsCreated) {
            Sha256Hash hash = out.getHash();
            if (blockStore.getTransactionOutput(hash, out.getIndex()) != null)
              throw new VerificationException("Block failed BIP30 test!");
          }
        for (StoredTransactionOutput out : txOutChanges.txOutsCreated)
          blockStore.addUnspentTransactionOutput(out);
        for (StoredTransactionOutput out : txOutChanges.txOutsSpent)
          blockStore.removeUnspentTransactionOutput(out);
      }
    } catch (VerificationException e) {
      scriptVerificationExecutor.shutdownNow();
      blockStore.abortDatabaseBatchWrite();
      throw e;
    } catch (BlockStoreException e) {
      scriptVerificationExecutor.shutdownNow();
      blockStore.abortDatabaseBatchWrite();
      throw e;
    }
    return txOutChanges;
  }
  @Override
  protected TransactionOutputChanges connectTransactions(int height, Block block)
      throws VerificationException, BlockStoreException {
    checkState(lock.isHeldByCurrentThread());
    if (block.transactions == null)
      throw new RuntimeException(
          "connectTransactions called with Block that didn't have transactions!");
    if (!params.passesCheckpoint(height, block.getHash()))
      throw new VerificationException("Block failed checkpoint lockin at " + height);

    blockStore.beginDatabaseBatchWrite();

    LinkedList<StoredTransactionOutput> txOutsSpent = new LinkedList<StoredTransactionOutput>();
    LinkedList<StoredTransactionOutput> txOutsCreated = new LinkedList<StoredTransactionOutput>();
    long sigOps = 0;
    final boolean enforcePayToScriptHash =
        block.getTimeSeconds() >= NetworkParameters.BIP16_ENFORCE_TIME;

    if (scriptVerificationExecutor.isShutdown())
      scriptVerificationExecutor =
          Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());

    List<Future<VerificationException>> listScriptVerificationResults =
        new ArrayList<Future<VerificationException>>(block.transactions.size());
    try {
      if (!params.isCheckpoint(height)) {
        // BIP30 violator blocks are ones that contain a duplicated transaction. They are all in the
        // checkpoints list and we therefore only check non-checkpoints for duplicated transactions
        // here. See the
        // BIP30 document for more details on this:
        // https://github.com/bitcoin/bips/blob/master/bip-0030.mediawiki
        for (Transaction tx : block.transactions) {
          Sha256Hash hash = tx.getHash();
          // If we already have unspent outputs for this hash, we saw the tx already. Either the
          // block is
          // being added twice (bug) or the block is a BIP30 violator.
          if (blockStore.hasUnspentOutputs(hash, tx.getOutputs().size()))
            throw new VerificationException("Block failed BIP30 test!");
          if (enforcePayToScriptHash) // We already check non-BIP16 sigops in
            // Block.verifyTransactions(true)
            sigOps += tx.getSigOpCount();
        }
      }
      Coin totalFees = Coin.ZERO;
      Coin coinbaseValue = null;
      for (final Transaction tx : block.transactions) {
        boolean isCoinBase = tx.isCoinBase();
        Coin valueIn = Coin.ZERO;
        Coin valueOut = Coin.ZERO;
        final List<Script> prevOutScripts = new LinkedList<Script>();
        if (!isCoinBase) {
          // For each input of the transaction remove the corresponding output from the set of
          // unspent
          // outputs.
          for (int index = 0; index < tx.getInputs().size(); index++) {
            TransactionInput in = tx.getInputs().get(index);
            StoredTransactionOutput prevOut =
                blockStore.getTransactionOutput(
                    in.getOutpoint().getHash(), in.getOutpoint().getIndex());
            if (prevOut == null)
              throw new VerificationException(
                  "Attempted to spend a non-existent or already spent output!");
            // Coinbases can't be spent until they mature, to avoid re-orgs destroying entire
            // transaction
            // chains. The assumption is there will ~never be re-orgs deeper than the spendable
            // coinbase
            // chain depth.
            if (height - prevOut.getHeight() < params.getSpendableCoinbaseDepth())
              throw new VerificationException(
                  "Tried to spend coinbase at depth " + (height - prevOut.getHeight()));
            // TODO: Check we're not spending the genesis transaction here. Satoshis code won't
            // allow it.
            valueIn = valueIn.add(prevOut.getValue());
            if (enforcePayToScriptHash) {
              if (new Script(prevOut.getScriptBytes()).isPayToScriptHash())
                sigOps += Script.getP2SHSigOpCount(in.getScriptBytes());
              if (sigOps > Block.MAX_BLOCK_SIGOPS)
                throw new VerificationException("Too many P2SH SigOps in block");
            }

            prevOutScripts.add(new Script(prevOut.getScriptBytes()));

            // in.getScriptSig().correctlySpends(tx, index, new Script(params,
            // prevOut.getScriptBytes(), 0, prevOut.getScriptBytes().length));

            blockStore.removeUnspentTransactionOutput(prevOut);
            txOutsSpent.add(prevOut);
          }
        }
        Sha256Hash hash = tx.getHash();
        for (TransactionOutput out : tx.getOutputs()) {
          valueOut = valueOut.add(out.getValue());
          // For each output, add it to the set of unspent outputs so it can be consumed in future.
          StoredTransactionOutput newOut =
              new StoredTransactionOutput(
                  hash, out.getIndex(), out.getValue(), height, isCoinBase, out.getScriptBytes());
          blockStore.addUnspentTransactionOutput(newOut);
          txOutsCreated.add(newOut);
        }
        // All values were already checked for being non-negative (as it is verified in
        // Transaction.verify())
        // but we check again here just for defence in depth. Transactions with zero output value
        // are OK.
        if (valueOut.signum() < 0 || valueOut.compareTo(NetworkParameters.MAX_MONEY) > 0)
          throw new VerificationException("Transaction output value out of range");
        if (isCoinBase) {
          coinbaseValue = valueOut;
        } else {
          if (valueIn.compareTo(valueOut) < 0 || valueIn.compareTo(NetworkParameters.MAX_MONEY) > 0)
            throw new VerificationException("Transaction input value out of range");
          totalFees = totalFees.add(valueIn.subtract(valueOut));
        }

        if (!isCoinBase && runScripts) {
          // Because correctlySpends modifies transactions, this must come after we are done with tx
          FutureTask<VerificationException> future =
              new FutureTask<VerificationException>(
                  new Verifier(tx, prevOutScripts, enforcePayToScriptHash));
          scriptVerificationExecutor.execute(future);
          listScriptVerificationResults.add(future);
        }
      }
      if (totalFees.compareTo(NetworkParameters.MAX_MONEY) > 0
          || block.getBlockInflation(height).add(totalFees).compareTo(coinbaseValue) < 0)
        throw new VerificationException("Transaction fees out of range");
      for (Future<VerificationException> future : listScriptVerificationResults) {
        VerificationException e;
        try {
          e = future.get();
        } catch (InterruptedException thrownE) {
          throw new RuntimeException(thrownE); // Shouldn't happen
        } catch (ExecutionException thrownE) {
          log.error("Script.correctlySpends threw a non-normal exception: " + thrownE.getCause());
          throw new VerificationException(
              "Bug in Script.correctlySpends, likely script malformed in some new and interesting way.",
              thrownE);
        }
        if (e != null) throw e;
      }
    } catch (VerificationException e) {
      scriptVerificationExecutor.shutdownNow();
      blockStore.abortDatabaseBatchWrite();
      throw e;
    } catch (BlockStoreException e) {
      scriptVerificationExecutor.shutdownNow();
      blockStore.abortDatabaseBatchWrite();
      throw e;
    }
    return new TransactionOutputChanges(txOutsCreated, txOutsSpent);
  }
Esempio n. 4
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  @Override
  /** Used during reorgs to connect a block previously on a fork */
  protected synchronized TransactionOutputChanges connectTransactions(StoredBlock newBlock)
      throws VerificationException, BlockStoreException, PrunedException {
    checkState(lock.isLocked());
    if (!params.passesCheckpoint(newBlock.getHeight(), newBlock.getHeader().getHash()))
      throw new VerificationException("Block failed checkpoint lockin at " + newBlock.getHeight());

    blockStore.beginDatabaseBatchWrite();
    StoredUndoableBlock block = blockStore.getUndoBlock(newBlock.getHeader().getHash());
    if (block == null) {
      // We're trying to re-org too deep and the data needed has been deleted.
      blockStore.abortDatabaseBatchWrite();
      throw new PrunedException(newBlock.getHeader().getHash());
    }
    TransactionOutputChanges txOutChanges;
    try {
      List<Transaction> transactions = block.getTransactions();
      if (transactions != null) {
        LinkedList<StoredTransactionOutput> txOutsSpent = new LinkedList<StoredTransactionOutput>();
        LinkedList<StoredTransactionOutput> txOutsCreated =
            new LinkedList<StoredTransactionOutput>();
        long sigOps = 0;
        final boolean enforcePayToScriptHash =
            newBlock.getHeader().getTimeSeconds() >= NetworkParameters.BIP16_ENFORCE_TIME;
        if (!params.isCheckpoint(newBlock.getHeight())) {
          for (Transaction tx : transactions) {
            Sha256Hash hash = tx.getHash();
            if (blockStore.hasUnspentOutputs(hash, tx.getOutputs().size()))
              throw new VerificationException("Block failed BIP30 test!");
          }
        }
        BigInteger totalFees = BigInteger.ZERO;
        BigInteger coinbaseValue = null;

        if (scriptVerificationExecutor.isShutdown())
          scriptVerificationExecutor =
              Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
        List<Future<VerificationException>> listScriptVerificationResults =
            new ArrayList<Future<VerificationException>>(transactions.size());
        for (final Transaction tx : transactions) {
          boolean isCoinBase = tx.isCoinBase();
          BigInteger valueIn = BigInteger.ZERO;
          BigInteger valueOut = BigInteger.ZERO;
          if (!isCoinBase) {
            for (int index = 0; index < tx.getInputs().size(); index++) {
              final TransactionInput in = tx.getInputs().get(index);
              final StoredTransactionOutput prevOut =
                  blockStore.getTransactionOutput(
                      in.getOutpoint().getHash(), in.getOutpoint().getIndex());
              if (prevOut == null)
                throw new VerificationException(
                    "Attempted spend of a non-existent or already spent output!");
              if (newBlock.getHeight() - prevOut.getHeight() < params.getSpendableCoinbaseDepth())
                throw new VerificationException(
                    "Tried to spend coinbase at depth "
                        + (newBlock.getHeight() - prevOut.getHeight()));
              valueIn = valueIn.add(prevOut.getValue());
              if (enforcePayToScriptHash) {
                Script script =
                    new Script(
                        params, prevOut.getScriptBytes(), 0, prevOut.getScriptBytes().length);
                if (script.isPayToScriptHash())
                  sigOps += Script.getP2SHSigOpCount(in.getScriptBytes());
                if (sigOps > Block.MAX_BLOCK_SIGOPS)
                  throw new VerificationException("Too many P2SH SigOps in block");
              }

              // All of these copies are terribly ugly, however without them,
              // I see some odd concurrency issues where scripts throw exceptions
              // (mostly "Attempted OP_* on empty stack" or similar) when they shouldn't.
              // In my tests, total time spent in net.usecredits.credits.core when
              // downloading the chain is < 0.5%, so doing this is no big efficiency issue.
              // TODO: Find out the underlying issue and create a better work-around
              // TODO: Thoroughly test that this fixes the issue like the non-StoredBlock version
              // does
              final int currentIndex = index;
              final Script scriptSig = in.getScriptSig();
              final Script scriptPubKey =
                  new Script(params, prevOut.getScriptBytes(), 0, prevOut.getScriptBytes().length);
              FutureTask<VerificationException> future =
                  new FutureTask<VerificationException>(
                      new Callable<VerificationException>() {
                        public VerificationException call() {
                          try {
                            scriptSig.correctlySpends(
                                tx, currentIndex, scriptPubKey, enforcePayToScriptHash);
                          } catch (VerificationException e) {
                            return e;
                          }
                          return null;
                        }
                      });
              scriptVerificationExecutor.execute(future);
              listScriptVerificationResults.add(future);

              blockStore.removeUnspentTransactionOutput(prevOut);
              txOutsSpent.add(prevOut);
            }
          }
          Sha256Hash hash = tx.getHash();
          for (TransactionOutput out : tx.getOutputs()) {
            valueOut = valueOut.add(out.getValue());
            StoredTransactionOutput newOut =
                new StoredTransactionOutput(
                    hash,
                    out.getIndex(),
                    out.getValue(),
                    newBlock.getHeight(),
                    isCoinBase,
                    out.getScriptBytes());
            blockStore.addUnspentTransactionOutput(newOut);
            txOutsCreated.add(newOut);
          }
          // All values were already checked for being non-negative (as it is verified in
          // Transaction.verify())
          // but we check again here just for defence in depth. Transactions with zero output value
          // are OK.
          if (valueOut.compareTo(BigInteger.ZERO) < 0 || valueOut.compareTo(params.MAX_MONEY) > 0)
            throw new VerificationException("Transaction output value out of rage");
          if (isCoinBase) {
            coinbaseValue = valueOut;
          } else {
            if (valueIn.compareTo(valueOut) < 0 || valueIn.compareTo(params.MAX_MONEY) > 0)
              throw new VerificationException("Transaction input value out of range");
            totalFees = totalFees.add(valueIn.subtract(valueOut));
          }
        }
        if (totalFees.compareTo(params.MAX_MONEY) > 0
            || newBlock
                    .getHeader()
                    .getBlockInflation(newBlock.getHeight())
                    .add(totalFees)
                    .compareTo(coinbaseValue)
                < 0) throw new VerificationException("Transaction fees out of range");
        txOutChanges = new TransactionOutputChanges(txOutsCreated, txOutsSpent);
        for (Future<VerificationException> future : listScriptVerificationResults) {
          VerificationException e;
          try {
            e = future.get();
          } catch (InterruptedException thrownE) {
            throw new RuntimeException(thrownE); // Shouldn't happen
          } catch (ExecutionException thrownE) {
            log.error("Script.correctlySpends threw a non-normal exception: " + thrownE.getCause());
            throw new VerificationException(
                "Bug in Script.correctlySpends, likely script malformed in some new and interesting way.");
          }
          if (e != null) throw e;
        }
      } else {
        txOutChanges = block.getTxOutChanges();
        if (!params.isCheckpoint(newBlock.getHeight()))
          for (StoredTransactionOutput out : txOutChanges.txOutsCreated) {
            Sha256Hash hash = out.getHash();
            if (blockStore.getTransactionOutput(hash, out.getIndex()) != null)
              throw new VerificationException("Block failed BIP30 test!");
          }
        for (StoredTransactionOutput out : txOutChanges.txOutsCreated)
          blockStore.addUnspentTransactionOutput(out);
        for (StoredTransactionOutput out : txOutChanges.txOutsSpent)
          blockStore.removeUnspentTransactionOutput(out);
      }
    } catch (VerificationException e) {
      scriptVerificationExecutor.shutdownNow();
      blockStore.abortDatabaseBatchWrite();
      throw e;
    } catch (BlockStoreException e) {
      scriptVerificationExecutor.shutdownNow();
      blockStore.abortDatabaseBatchWrite();
      throw e;
    }
    return txOutChanges;
  }
Esempio n. 5
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  @Override
  protected TransactionOutputChanges connectTransactions(int height, Block block)
      throws VerificationException, BlockStoreException {
    checkState(lock.isLocked());
    if (block.transactions == null)
      throw new RuntimeException(
          "connectTransactions called with Block that didn't have transactions!");
    if (!params.passesCheckpoint(height, block.getHash()))
      throw new VerificationException("Block failed checkpoint lockin at " + height);

    blockStore.beginDatabaseBatchWrite();

    LinkedList<StoredTransactionOutput> txOutsSpent = new LinkedList<StoredTransactionOutput>();
    LinkedList<StoredTransactionOutput> txOutsCreated = new LinkedList<StoredTransactionOutput>();
    long sigOps = 0;
    final boolean enforceBIP16 = block.getTimeSeconds() >= NetworkParameters.BIP16_ENFORCE_TIME;

    if (scriptVerificationExecutor.isShutdown())
      scriptVerificationExecutor =
          Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());

    List<Future<VerificationException>> listScriptVerificationResults =
        new ArrayList<Future<VerificationException>>(block.transactions.size());
    try {
      if (!params.isCheckpoint(height)) {
        // BIP30 violator blocks are ones that contain a duplicated transaction. They are all in the
        // checkpoints list and we therefore only check non-checkpoints for duplicated transactions
        // here. See the
        // BIP30 document for more details on this: https://en.litecoin.it/wiki/BIP_0030
        for (Transaction tx : block.transactions) {
          Sha256Hash hash = tx.getHash();
          // If we already have unspent outputs for this hash, we saw the tx already. Either the
          // block is
          // being added twice (bug) or the block is a BIP30 violator.
          if (blockStore.hasUnspentOutputs(hash, tx.getOutputs().size()))
            throw new VerificationException("Block failed BIP30 test!");
          if (enforceBIP16) // We already check non-BIP16 sigops in Block.verifyTransactions(true)
          sigOps += tx.getSigOpCount();
        }
      }
      BigInteger totalFees = BigInteger.ZERO;
      BigInteger coinbaseValue = null;
      for (Transaction tx : block.transactions) {
        boolean isCoinBase = tx.isCoinBase();
        BigInteger valueIn = BigInteger.ZERO;
        BigInteger valueOut = BigInteger.ZERO;
        if (!isCoinBase) {
          // For each input of the transaction remove the corresponding output from the set of
          // unspent
          // outputs.
          for (int index = 0; index < tx.getInputs().size(); index++) {
            TransactionInput in = tx.getInputs().get(index);
            StoredTransactionOutput prevOut =
                blockStore.getTransactionOutput(
                    in.getOutpoint().getHash(), in.getOutpoint().getIndex());
            if (prevOut == null)
              throw new VerificationException(
                  "Attempted to spend a non-existent or already spent output!");
            // Coinbases can't be spent until they mature, to avoid re-orgs destroying entire
            // transaction
            // chains. The assumption is there will ~never be re-orgs deeper than the spendable
            // coinbase
            // chain depth.
            if (height - prevOut.getHeight() < params.getSpendableCoinbaseDepth())
              throw new VerificationException(
                  "Tried to spend coinbase at depth " + (height - prevOut.getHeight()));
            // TODO: Check we're not spending the genesis transaction here. Satoshis code won't
            // allow it.
            valueIn = valueIn.add(prevOut.getValue());
            if (enforceBIP16) {
              if (new Script(params, prevOut.getScriptBytes(), 0, prevOut.getScriptBytes().length)
                  .isPayToScriptHash()) sigOps += Script.getP2SHSigOpCount(in.getScriptBytes());
              if (sigOps > Block.MAX_BLOCK_SIGOPS)
                throw new VerificationException("Too many P2SH SigOps in block");
            }

            // All of these copies are terribly ugly, however without them,
            // I see some odd concurrency issues where scripts throw exceptions
            // (mostly "Attempted OP_* on empty stack" or similar) when they shouldn't.
            // In my tests, total time spent in net.usecredits.credits.core when
            // downloading the chain is < 0.5%, so doing this is no big efficiency issue.
            // TODO: Find out the underlying issue and create a better work-around
            final int currentIndex = index;
            final Transaction txCache;
            try {
              txCache = new Transaction(params, tx.unsafeLitecoinSerialize());
            } catch (ProtocolException e1) {
              throw new RuntimeException(e1);
            }
            final Script scriptSig = in.getScriptSig();
            final Script scriptPubKey =
                new Script(params, prevOut.getScriptBytes(), 0, prevOut.getScriptBytes().length);
            FutureTask<VerificationException> future =
                new FutureTask<VerificationException>(
                    new Callable<VerificationException>() {
                      public VerificationException call() {
                        try {
                          scriptSig.correctlySpends(
                              txCache, currentIndex, scriptPubKey, enforceBIP16);
                        } catch (VerificationException e) {
                          return e;
                        }
                        return null;
                      }
                    });
            scriptVerificationExecutor.execute(future);
            listScriptVerificationResults.add(future);

            // in.getScriptSig().correctlySpends(tx, index, new Script(params,
            // prevOut.getScriptBytes(), 0, prevOut.getScriptBytes().length));

            blockStore.removeUnspentTransactionOutput(prevOut);
            txOutsSpent.add(prevOut);
          }
        }
        Sha256Hash hash = tx.getHash();
        for (TransactionOutput out : tx.getOutputs()) {
          valueOut = valueOut.add(out.getValue());
          // For each output, add it to the set of unspent outputs so it can be consumed in future.
          StoredTransactionOutput newOut =
              new StoredTransactionOutput(
                  hash, out.getIndex(), out.getValue(), height, isCoinBase, out.getScriptBytes());
          blockStore.addUnspentTransactionOutput(newOut);
          txOutsCreated.add(newOut);
        }
        // All values were already checked for being non-negative (as it is verified in
        // Transaction.verify())
        // but we check again here just for defence in depth. Transactions with zero output value
        // are OK.
        if (valueOut.compareTo(BigInteger.ZERO) < 0 || valueOut.compareTo(params.MAX_MONEY) > 0)
          throw new VerificationException("Transaction output value out of rage");
        if (isCoinBase) {
          coinbaseValue = valueOut;
        } else {
          if (valueIn.compareTo(valueOut) < 0 || valueIn.compareTo(params.MAX_MONEY) > 0)
            throw new VerificationException("Transaction input value out of range");
          totalFees = totalFees.add(valueIn.subtract(valueOut));
        }
      }
      if (totalFees.compareTo(params.MAX_MONEY) > 0
          || block.getBlockInflation(height).add(totalFees).compareTo(coinbaseValue) < 0)
        throw new VerificationException("Transaction fees out of range");
      for (Future<VerificationException> future : listScriptVerificationResults) {
        VerificationException e;
        try {
          e = future.get();
        } catch (InterruptedException thrownE) {
          throw new RuntimeException(thrownE); // Shouldn't happen
        } catch (ExecutionException thrownE) {
          log.error("Script.correctlySpends threw a non-normal exception: " + thrownE.getCause());
          throw new VerificationException(
              "Bug in Script.correctlySpends, likely script malformed in some new and interesting way.");
        }
        if (e != null) throw e;
      }
    } catch (VerificationException e) {
      scriptVerificationExecutor.shutdownNow();
      blockStore.abortDatabaseBatchWrite();
      throw e;
    } catch (BlockStoreException e) {
      scriptVerificationExecutor.shutdownNow();
      blockStore.abortDatabaseBatchWrite();
      throw e;
    }
    return new TransactionOutputChanges(txOutsCreated, txOutsSpent);
  }