Golang Block.Hash方法代码示例

// dbIndexDisconnectBlock removes all of the index entries associated with the
// given block using the provided indexer and updates the tip of the indexer
// accordingly.  An error will be returned if the current tip for the indexer is
// not the passed block.
func dbIndexDisconnectBlock(dbTx database.Tx, indexer Indexer, block *btcutil.Block, view *blockchain.UtxoViewpoint) error {
	// Assert that the block being disconnected is the current tip of the
	// index.
	idxKey := indexer.Key()
	curTipHash, _, err := dbFetchIndexerTip(dbTx, idxKey)
	if err != nil {
		return err
	}
	if !curTipHash.IsEqual(block.Hash()) {
		return AssertError(fmt.Sprintf("dbIndexDisconnectBlock must "+
			"be called with the block at the current index tip "+
			"(%s, tip %s, block %s)", indexer.Name(),
			curTipHash, block.Hash()))
	}

	// Notify the indexer with the disconnected block so it can remove all
	// of the appropriate entries.
	if err := indexer.DisconnectBlock(dbTx, block, view); err != nil {
		return err
	}

	// Update the current index tip.
	prevHash := &block.MsgBlock().Header.PrevBlock
	return dbPutIndexerTip(dbTx, idxKey, prevHash, block.Height()-1)
}

// ConnectBlock is invoked by the index manager when a new block has been
// connected to the main chain.  This indexer adds a mapping for each address
// the transactions in the block involve.
//
// This is part of the Indexer interface.
func (idx *AddrIndex) ConnectBlock(dbTx database.Tx, block *btcutil.Block, view *blockchain.UtxoViewpoint) error {
	// The offset and length of the transactions within the serialized
	// block.
	txLocs, err := block.TxLoc()
	if err != nil {
		return err
	}

	// Get the internal block ID associated with the block.
	blockID, err := dbFetchBlockIDByHash(dbTx, block.Hash())
	if err != nil {
		return err
	}

	// Build all of the address to transaction mappings in a local map.
	addrsToTxns := make(writeIndexData)
	idx.indexBlock(addrsToTxns, block, view)

	// Add all of the index entries for each address.
	addrIdxBucket := dbTx.Metadata().Bucket(addrIndexKey)
	for addrKey, txIdxs := range addrsToTxns {
		for _, txIdx := range txIdxs {
			err := dbPutAddrIndexEntry(addrIdxBucket, addrKey,
				blockID, txLocs[txIdx])
			if err != nil {
				return err
			}
		}
	}

	return nil
}

// maybeAcceptBlock potentially accepts a block into the block chain and, if
// accepted, returns whether or not it is on the main chain.  It performs
// several validation checks which depend on its position within the block chain
// before adding it.  The block is expected to have already gone through
// ProcessBlock before calling this function with it.
//
// The flags modify the behavior of this function as follows:
//  - BFDryRun: The memory chain index will not be pruned and no accept
//    notification will be sent since the block is not being accepted.
//
// The flags are also passed to checkBlockContext and connectBestChain.  See
// their documentation for how the flags modify their behavior.
//
// This function MUST be called with the chain state lock held (for writes).
func (b *BlockChain) maybeAcceptBlock(block *btcutil.Block, flags BehaviorFlags) (bool, error) {
	dryRun := flags&BFDryRun == BFDryRun

	// Get a block node for the block previous to this one.  Will be nil
	// if this is the genesis block.
	prevNode, err := b.getPrevNodeFromBlock(block)
	if err != nil {
		log.Errorf("getPrevNodeFromBlock: %v", err)
		return false, err
	}

	// The height of this block is one more than the referenced previous
	// block.
	blockHeight := int32(0)
	if prevNode != nil {
		blockHeight = prevNode.height + 1
	}
	block.SetHeight(blockHeight)

	// The block must pass all of the validation rules which depend on the
	// position of the block within the block chain.
	err = b.checkBlockContext(block, prevNode, flags)
	if err != nil {
		return false, err
	}

	// Create a new block node for the block and add it to the in-memory
	// block chain (could be either a side chain or the main chain).
	blockHeader := &block.MsgBlock().Header
	newNode := newBlockNode(blockHeader, block.Hash(), blockHeight)
	if prevNode != nil {
		newNode.parent = prevNode
		newNode.height = blockHeight
		newNode.workSum.Add(prevNode.workSum, newNode.workSum)
	}

	// Connect the passed block to the chain while respecting proper chain
	// selection according to the chain with the most proof of work.  This
	// also handles validation of the transaction scripts.
	isMainChain, err := b.connectBestChain(newNode, block, flags)
	if err != nil {
		return false, err
	}

	// Notify the caller that the new block was accepted into the block
	// chain.  The caller would typically want to react by relaying the
	// inventory to other peers.
	if !dryRun {
		b.chainLock.Unlock()
		b.sendNotification(NTBlockAccepted, block)
		b.chainLock.Lock()
	}

	return isMainChain, nil
}

// connectTransactions updates the view by adding all new utxos created by all
// of the transactions in the passed block, marking all utxos the transactions
// spend as spent, and setting the best hash for the view to the passed block.
// In addition, when the 'stxos' argument is not nil, it will be updated to
// append an entry for each spent txout.
func (view *UtxoViewpoint) connectTransactions(block *btcutil.Block, stxos *[]spentTxOut) error {
	for _, tx := range block.Transactions() {
		err := view.connectTransaction(tx, block.Height(), stxos)
		if err != nil {
			return err
		}
	}

	// Update the best hash for view to include this block since all of its
	// transactions have been connected.
	view.SetBestHash(block.Hash())
	return nil
}

// DisconnectBlock is invoked by the index manager when a block has been
// disconnected from the main chain.  This indexer removes the
// hash-to-transaction mapping for every transaction in the block.
//
// This is part of the Indexer interface.
func (idx *TxIndex) DisconnectBlock(dbTx database.Tx, block *btcutil.Block, view *blockchain.UtxoViewpoint) error {
	// Remove all of the transactions in the block from the index.
	if err := dbRemoveTxIndexEntries(dbTx, block); err != nil {
		return err
	}

	// Remove the block ID index entry for the block being disconnected and
	// decrement the current internal block ID to account for it.
	if err := dbRemoveBlockIDIndexEntry(dbTx, block.Hash()); err != nil {
		return err
	}
	idx.curBlockID--
	return nil
}

// CheckConnectBlock performs several checks to confirm connecting the passed
// block to the main chain does not violate any rules.  An example of some of
// the checks performed are ensuring connecting the block would not cause any
// duplicate transaction hashes for old transactions that aren't already fully
// spent, double spends, exceeding the maximum allowed signature operations
// per block, invalid values in relation to the expected block subsidy, or fail
// transaction script validation.
//
// This function is safe for concurrent access.
func (b *BlockChain) CheckConnectBlock(block *btcutil.Block) error {
	b.chainLock.Lock()
	defer b.chainLock.Unlock()

	prevNode := b.bestNode
	newNode := newBlockNode(&block.MsgBlock().Header, block.Hash(),
		prevNode.height+1)
	newNode.parent = prevNode
	newNode.workSum.Add(prevNode.workSum, newNode.workSum)

	// Leave the spent txouts entry nil in the state since the information
	// is not needed and thus extra work can be avoided.
	view := NewUtxoViewpoint()
	view.SetBestHash(prevNode.hash)
	return b.checkConnectBlock(newNode, block, view, nil)
}

// ConnectBlock is invoked by the index manager when a new block has been
// connected to the main chain.  This indexer adds a hash-to-transaction mapping
// for every transaction in the passed block.
//
// This is part of the Indexer interface.
func (idx *TxIndex) ConnectBlock(dbTx database.Tx, block *btcutil.Block, view *blockchain.UtxoViewpoint) error {
	// Increment the internal block ID to use for the block being connected
	// and add all of the transactions in the block to the index.
	newBlockID := idx.curBlockID + 1
	if err := dbAddTxIndexEntries(dbTx, block, newBlockID); err != nil {
		return err
	}

	// Add the new block ID index entry for the block being connected and
	// update the current internal block ID accordingly.
	err := dbPutBlockIDIndexEntry(dbTx, block.Hash(), newBlockID)
	if err != nil {
		return err
	}
	idx.curBlockID = newBlockID
	return nil
}

// submitBlock submits the passed block to network after ensuring it passes all
// of the consensus validation rules.
func (m *CPUMiner) submitBlock(block *btcutil.Block) bool {
	m.submitBlockLock.Lock()
	defer m.submitBlockLock.Unlock()

	// Ensure the block is not stale since a new block could have shown up
	// while the solution was being found.  Typically that condition is
	// detected and all work on the stale block is halted to start work on
	// a new block, but the check only happens periodically, so it is
	// possible a block was found and submitted in between.
	msgBlock := block.MsgBlock()
	if !msgBlock.Header.PrevBlock.IsEqual(m.g.BestSnapshot().Hash) {
		log.Debugf("Block submitted via CPU miner with previous "+
			"block %s is stale", msgBlock.Header.PrevBlock)
		return false
	}

	// Process this block using the same rules as blocks coming from other
	// nodes.  This will in turn relay it to the network like normal.
	isOrphan, err := m.cfg.ProcessBlock(block, blockchain.BFNone)
	if err != nil {
		// Anything other than a rule violation is an unexpected error,
		// so log that error as an internal error.
		if _, ok := err.(blockchain.RuleError); !ok {
			log.Errorf("Unexpected error while processing "+
				"block submitted via CPU miner: %v", err)
			return false
		}

		log.Debugf("Block submitted via CPU miner rejected: %v", err)
		return false
	}
	if isOrphan {
		log.Debugf("Block submitted via CPU miner is an orphan")
		return false
	}

	// The block was accepted.
	coinbaseTx := block.MsgBlock().Transactions[0].TxOut[0]
	log.Infof("Block submitted via CPU miner accepted (hash %s, "+
		"amount %v)", block.Hash(), btcutil.Amount(coinbaseTx.Value))
	return true
}

// dbIndexConnectBlock adds all of the index entries associated with the
// given block using the provided indexer and updates the tip of the indexer
// accordingly.  An error will be returned if the current tip for the indexer is
// not the previous block for the passed block.
func dbIndexConnectBlock(dbTx database.Tx, indexer Indexer, block *btcutil.Block, view *blockchain.UtxoViewpoint) error {
	// Assert that the block being connected properly connects to the
	// current tip of the index.
	idxKey := indexer.Key()
	curTipHash, _, err := dbFetchIndexerTip(dbTx, idxKey)
	if err != nil {
		return err
	}
	if !curTipHash.IsEqual(&block.MsgBlock().Header.PrevBlock) {
		return AssertError(fmt.Sprintf("dbIndexConnectBlock must be "+
			"called with a block that extends the current index "+
			"tip (%s, tip %s, block %s)", indexer.Name(),
			curTipHash, block.Hash()))
	}

	// Notify the indexer with the connected block so it can index it.
	if err := indexer.ConnectBlock(dbTx, block, view); err != nil {
		return err
	}

	// Update the current index tip.
	return dbPutIndexerTip(dbTx, idxKey, block.Hash(), block.Height())
}

// IsCheckpointCandidate returns whether or not the passed block is a good
// checkpoint candidate.
//
// The factors used to determine a good checkpoint are:
//  - The block must be in the main chain
//  - The block must be at least 'CheckpointConfirmations' blocks prior to the
//    current end of the main chain
//  - The timestamps for the blocks before and after the checkpoint must have
//    timestamps which are also before and after the checkpoint, respectively
//    (due to the median time allowance this is not always the case)
//  - The block must not contain any strange transaction such as those with
//    nonstandard scripts
//
// The intent is that candidates are reviewed by a developer to make the final
// decision and then manually added to the list of checkpoints for a network.
//
// This function is safe for concurrent access.
func (b *BlockChain) IsCheckpointCandidate(block *btcutil.Block) (bool, error) {
	b.chainLock.RLock()
	defer b.chainLock.RUnlock()

	// Checkpoints must be enabled.
	if b.noCheckpoints {
		return false, fmt.Errorf("checkpoints are disabled")
	}

	var isCandidate bool
	err := b.db.View(func(dbTx database.Tx) error {
		// A checkpoint must be in the main chain.
		blockHeight, err := dbFetchHeightByHash(dbTx, block.Hash())
		if err != nil {
			// Only return an error if it's not due to the block not
			// being in the main chain.
			if !isNotInMainChainErr(err) {
				return err
			}
			return nil
		}

		// Ensure the height of the passed block and the entry for the
		// block in the main chain match.  This should always be the
		// case unless the caller provided an invalid block.
		if blockHeight != block.Height() {
			return fmt.Errorf("passed block height of %d does not "+
				"match the main chain height of %d",
				block.Height(), blockHeight)
		}

		// A checkpoint must be at least CheckpointConfirmations blocks
		// before the end of the main chain.
		mainChainHeight := b.bestNode.height
		if blockHeight > (mainChainHeight - CheckpointConfirmations) {
			return nil
		}

		// Get the previous block header.
		prevHash := &block.MsgBlock().Header.PrevBlock
		prevHeader, err := dbFetchHeaderByHash(dbTx, prevHash)
		if err != nil {
			return err
		}

		// Get the next block header.
		nextHeader, err := dbFetchHeaderByHeight(dbTx, blockHeight+1)
		if err != nil {
			return err
		}

		// A checkpoint must have timestamps for the block and the
		// blocks on either side of it in order (due to the median time
		// allowance this is not always the case).
		prevTime := prevHeader.Timestamp
		curTime := block.MsgBlock().Header.Timestamp
		nextTime := nextHeader.Timestamp
		if prevTime.After(curTime) || nextTime.Before(curTime) {
			return nil
		}

		// A checkpoint must have transactions that only contain
		// standard scripts.
		for _, tx := range block.Transactions() {
			if isNonstandardTransaction(tx) {
				return nil
			}
		}

		// All of the checks passed, so the block is a candidate.
		isCandidate = true
		return nil
	})
	return isCandidate, err
}

// CreateBlock creates a new block building from the previous block with a
// specified blockversion and timestamp. If the timestamp passed is zero (not
// initialized), then the timestamp of the previous block will be used plus 1
// second is used. Passing nil for the previous block results in a block that
// builds off of the genesis block for the specified chain.
func CreateBlock(prevBlock *btcutil.Block, inclusionTxs []*btcutil.Tx,
	blockVersion int32, blockTime time.Time,
	miningAddr btcutil.Address, net *chaincfg.Params) (*btcutil.Block, error) {

	var (
		prevHash      *chainhash.Hash
		blockHeight   int32
		prevBlockTime time.Time
	)

	// If the previous block isn't specified, then we'll construct a block
	// that builds off of the genesis block for the chain.
	if prevBlock == nil {
		prevHash = net.GenesisHash
		blockHeight = 1
		prevBlockTime = net.GenesisBlock.Header.Timestamp.Add(time.Minute)
	} else {
		prevHash = prevBlock.Hash()
		blockHeight = prevBlock.Height() + 1
		prevBlockTime = prevBlock.MsgBlock().Header.Timestamp
	}

	// If a target block time was specified, then use that as the header's
	// timestamp. Otherwise, add one second to the previous block unless
	// it's the genesis block in which case use the current time.
	var ts time.Time
	switch {
	case !blockTime.IsZero():
		ts = blockTime
	default:
		ts = prevBlockTime.Add(time.Second)
	}

	extraNonce := uint64(0)
	coinbaseScript, err := standardCoinbaseScript(blockHeight, extraNonce)
	if err != nil {
		return nil, err
	}
	coinbaseTx, err := createCoinbaseTx(coinbaseScript, blockHeight,
		miningAddr, net)
	if err != nil {
		return nil, err
	}

	// Create a new block ready to be solved.
	blockTxns := []*btcutil.Tx{coinbaseTx}
	if inclusionTxs != nil {
		blockTxns = append(blockTxns, inclusionTxs...)
	}
	merkles := blockchain.BuildMerkleTreeStore(blockTxns, false)
	var block wire.MsgBlock
	block.Header = wire.BlockHeader{
		Version:    blockVersion,
		PrevBlock:  *prevHash,
		MerkleRoot: *merkles[len(merkles)-1],
		Timestamp:  ts,
		Bits:       net.PowLimitBits,
	}
	for _, tx := range blockTxns {
		if err := block.AddTransaction(tx.MsgTx()); err != nil {
			return nil, err
		}
	}

	found := solveBlock(&block.Header, net.PowLimit)
	if !found {
		return nil, errors.New("Unable to solve block")
	}

	utilBlock := btcutil.NewBlock(&block)
	utilBlock.SetHeight(blockHeight)
	return utilBlock, nil
}

// checkBlockScripts executes and validates the scripts for all transactions in
// the passed block using multiple goroutines.
func checkBlockScripts(block *btcutil.Block, utxoView *UtxoViewpoint,
	scriptFlags txscript.ScriptFlags, sigCache *txscript.SigCache,
	hashCache *txscript.HashCache) error {

	// First determine if segwit is active according to the scriptFlags. If
	// it isn't then we don't need to interact with the HashCache.
	segwitActive := scriptFlags&txscript.ScriptVerifyWitness == txscript.ScriptVerifyWitness

	// Collect all of the transaction inputs and required information for
	// validation for all transactions in the block into a single slice.
	numInputs := 0
	for _, tx := range block.Transactions() {
		numInputs += len(tx.MsgTx().TxIn)
	}
	txValItems := make([]*txValidateItem, 0, numInputs)
	for _, tx := range block.Transactions() {
		sha := tx.Hash()

		// If the HashCache is present, and it doesn't yet contain the
		// partial sighashes for this transaction, then we add the
		// sighashes for the transaction. This allows us to take
		// advantage of the potential speed savings due to the new
		// digest algorithm (BIP0143).
		if segwitActive && hashCache != nil &&
			!hashCache.ContainsHashes(sha) {
			hashCache.AddSigHashes(tx.MsgTx())
		}

		var cachedHashes *txscript.TxSigHashes
		if segwitActive {
			if hashCache != nil {
				cachedHashes, _ = hashCache.GetSigHashes(sha)
			} else {
				cachedHashes = txscript.NewTxSigHashes(tx.MsgTx())
			}
		}

		for txInIdx, txIn := range tx.MsgTx().TxIn {
			// Skip coinbases.
			if txIn.PreviousOutPoint.Index == math.MaxUint32 {
				continue
			}

			txVI := &txValidateItem{
				txInIndex: txInIdx,
				txIn:      txIn,
				tx:        tx,
				sigHashes: cachedHashes,
			}
			txValItems = append(txValItems, txVI)
		}
	}

	// Validate all of the inputs.
	validator := newTxValidator(utxoView, scriptFlags, sigCache, hashCache)
	start := time.Now()
	if err := validator.Validate(txValItems); err != nil {
		return err
	}
	elapsed := time.Since(start)

	log.Tracef("block %v took %v to verify", block.Hash(), elapsed)

	// If the HashCache is present, once we have validated the block, we no
	// longer need the cached hashes for these transactions, so we purge
	// them from the cache.
	if segwitActive && hashCache != nil {
		for _, tx := range block.Transactions() {
			hashCache.PurgeSigHashes(tx.Hash())
		}
	}

	return nil
}

// ProcessBlock is the main workhorse for handling insertion of new blocks into
// the block chain.  It includes functionality such as rejecting duplicate
// blocks, ensuring blocks follow all rules, orphan handling, and insertion into
// the block chain along with best chain selection and reorganization.
//
// When no errors occurred during processing, the first return value indicates
// whether or not the block is on the main chain and the second indicates
// whether or not the block is an orphan.
//
// This function is safe for concurrent access.
func (b *BlockChain) ProcessBlock(block *btcutil.Block, flags BehaviorFlags) (bool, bool, error) {
	b.chainLock.Lock()
	defer b.chainLock.Unlock()

	fastAdd := flags&BFFastAdd == BFFastAdd
	dryRun := flags&BFDryRun == BFDryRun

	blockHash := block.Hash()
	log.Tracef("Processing block %v", blockHash)

	// The block must not already exist in the main chain or side chains.
	exists, err := b.blockExists(blockHash)
	if err != nil {
		return false, false, err
	}
	if exists {
		str := fmt.Sprintf("already have block %v", blockHash)
		return false, false, ruleError(ErrDuplicateBlock, str)
	}

	// The block must not already exist as an orphan.
	if _, exists := b.orphans[*blockHash]; exists {
		str := fmt.Sprintf("already have block (orphan) %v", blockHash)
		return false, false, ruleError(ErrDuplicateBlock, str)
	}

	// Perform preliminary sanity checks on the block and its transactions.
	err = checkBlockSanity(block, b.chainParams.PowLimit, b.timeSource, flags)
	if err != nil {
		return false, false, err
	}

	// Find the previous checkpoint and perform some additional checks based
	// on the checkpoint.  This provides a few nice properties such as
	// preventing old side chain blocks before the last checkpoint,
	// rejecting easy to mine, but otherwise bogus, blocks that could be
	// used to eat memory, and ensuring expected (versus claimed) proof of
	// work requirements since the previous checkpoint are met.
	blockHeader := &block.MsgBlock().Header
	checkpointBlock, err := b.findPreviousCheckpoint()
	if err != nil {
		return false, false, err
	}
	if checkpointBlock != nil {
		// Ensure the block timestamp is after the checkpoint timestamp.
		checkpointHeader := &checkpointBlock.MsgBlock().Header
		checkpointTime := checkpointHeader.Timestamp
		if blockHeader.Timestamp.Before(checkpointTime) {
			str := fmt.Sprintf("block %v has timestamp %v before "+
				"last checkpoint timestamp %v", blockHash,
				blockHeader.Timestamp, checkpointTime)
			return false, false, ruleError(ErrCheckpointTimeTooOld, str)
		}
		if !fastAdd {
			// Even though the checks prior to now have already ensured the
			// proof of work exceeds the claimed amount, the claimed amount
			// is a field in the block header which could be forged.  This
			// check ensures the proof of work is at least the minimum
			// expected based on elapsed time since the last checkpoint and
			// maximum adjustment allowed by the retarget rules.
			duration := blockHeader.Timestamp.Sub(checkpointTime)
			requiredTarget := CompactToBig(b.calcEasiestDifficulty(
				checkpointHeader.Bits, duration))
			currentTarget := CompactToBig(blockHeader.Bits)
			if currentTarget.Cmp(requiredTarget) > 0 {
				str := fmt.Sprintf("block target difficulty of %064x "+
					"is too low when compared to the previous "+
					"checkpoint", currentTarget)
				return false, false, ruleError(ErrDifficultyTooLow, str)
			}
		}
	}

	// Handle orphan blocks.
	prevHash := &blockHeader.PrevBlock
	prevHashExists, err := b.blockExists(prevHash)
	if err != nil {
		return false, false, err
	}
	if !prevHashExists {
		if !dryRun {
			log.Infof("Adding orphan block %v with parent %v",
				blockHash, prevHash)
			b.addOrphanBlock(block)
		}

		return false, true, nil
	}

	// The block has passed all context independent checks and appears sane
//.........这里部分代码省略.........