示例#1
0
// findCandidates searches the chain backwards for checkpoint candidates and
// returns a slice of found candidates, if any.  It also stops searching for
// candidates at the last checkpoint that is already hard coded into btcchain
// since there is no point in finding candidates before already existing
// checkpoints.
func findCandidates(chain *blockchain.BlockChain, latestHash *chainhash.Hash) ([]*chaincfg.Checkpoint, error) {
	// Start with the latest block of the main chain.
	block, err := chain.BlockByHash(latestHash)
	if err != nil {
		return nil, err
	}

	// Get the latest known checkpoint.
	latestCheckpoint := chain.LatestCheckpoint()
	if latestCheckpoint == nil {
		// Set the latest checkpoint to the genesis block if there isn't
		// already one.
		latestCheckpoint = &chaincfg.Checkpoint{
			Hash:   activeNetParams.GenesisHash,
			Height: 0,
		}
	}

	// The latest known block must be at least the last known checkpoint
	// plus required checkpoint confirmations.
	checkpointConfirmations := int32(blockchain.CheckpointConfirmations)
	requiredHeight := latestCheckpoint.Height + checkpointConfirmations
	if block.Height() < requiredHeight {
		return nil, fmt.Errorf("the block database is only at height "+
			"%d which is less than the latest checkpoint height "+
			"of %d plus required confirmations of %d",
			block.Height(), latestCheckpoint.Height,
			checkpointConfirmations)
	}

	// For the first checkpoint, the required height is any block after the
	// genesis block, so long as the chain has at least the required number
	// of confirmations (which is enforced above).
	if len(activeNetParams.Checkpoints) == 0 {
		requiredHeight = 1
	}

	// Indeterminate progress setup.
	numBlocksToTest := block.Height() - requiredHeight
	progressInterval := (numBlocksToTest / 100) + 1 // min 1
	fmt.Print("Searching for candidates")
	defer fmt.Println()

	// Loop backwards through the chain to find checkpoint candidates.
	candidates := make([]*chaincfg.Checkpoint, 0, cfg.NumCandidates)
	numTested := int32(0)
	for len(candidates) < cfg.NumCandidates && block.Height() > requiredHeight {
		// Display progress.
		if numTested%progressInterval == 0 {
			fmt.Print(".")
		}

		// Determine if this block is a checkpoint candidate.
		isCandidate, err := chain.IsCheckpointCandidate(block)
		if err != nil {
			return nil, err
		}

		// All checks passed, so this node seems like a reasonable
		// checkpoint candidate.
		if isCandidate {
			checkpoint := chaincfg.Checkpoint{
				Height: block.Height(),
				Hash:   block.Hash(),
			}
			candidates = append(candidates, &checkpoint)
		}

		prevHash := &block.MsgBlock().Header.PrevBlock
		block, err = chain.BlockByHash(prevHash)
		if err != nil {
			return nil, err
		}
		numTested++
	}
	return candidates, nil
}
示例#2
0
文件: manager.go 项目: Roasbeef/btcd
// Init initializes the enabled indexes.  This is called during chain
// initialization and primarily consists of catching up all indexes to the
// current best chain tip.  This is necessary since each index can be disabled
// and re-enabled at any time and attempting to catch-up indexes at the same
// time new blocks are being downloaded would lead to an overall longer time to
// catch up due to the I/O contention.
//
// This is part of the blockchain.IndexManager interface.
func (m *Manager) Init(chain *blockchain.BlockChain) error {
	// Nothing to do when no indexes are enabled.
	if len(m.enabledIndexes) == 0 {
		return nil
	}

	// Finish and drops that were previously interrupted.
	if err := m.maybeFinishDrops(); err != nil {
		return err
	}

	// Create the initial state for the indexes as needed.
	err := m.db.Update(func(dbTx database.Tx) error {
		// Create the bucket for the current tips as needed.
		meta := dbTx.Metadata()
		_, err := meta.CreateBucketIfNotExists(indexTipsBucketName)
		if err != nil {
			return err
		}

		return m.maybeCreateIndexes(dbTx)
	})
	if err != nil {
		return err
	}

	// Initialize each of the enabled indexes.
	for _, indexer := range m.enabledIndexes {
		if err := indexer.Init(); err != nil {
			return err
		}
	}

	// Rollback indexes to the main chain if their tip is an orphaned fork.
	// This is fairly unlikely, but it can happen if the chain is
	// reorganized while the index is disabled.  This has to be done in
	// reverse order because later indexes can depend on earlier ones.
	for i := len(m.enabledIndexes); i > 0; i-- {
		indexer := m.enabledIndexes[i-1]

		// Fetch the current tip for the index.
		var height int32
		var hash *chainhash.Hash
		err := m.db.View(func(dbTx database.Tx) error {
			idxKey := indexer.Key()
			hash, height, err = dbFetchIndexerTip(dbTx, idxKey)
			return err
		})
		if err != nil {
			return err
		}

		// Nothing to do if the index does not have any entries yet.
		if height == -1 {
			continue
		}

		// Loop until the tip is a block that exists in the main chain.
		initialHeight := height
		for {
			exists, err := chain.MainChainHasBlock(hash)
			if err != nil {
				return err
			}
			if exists {
				break
			}

			// At this point the index tip is orphaned, so load the
			// orphaned block from the database directly and
			// disconnect it from the index.  The block has to be
			// loaded directly since it is no longer in the main
			// chain and thus the chain.BlockByHash function would
			// error.
			err = m.db.Update(func(dbTx database.Tx) error {
				blockBytes, err := dbTx.FetchBlock(hash)
				if err != nil {
					return err
				}
				block, err := btcutil.NewBlockFromBytes(blockBytes)
				if err != nil {
					return err
				}
				block.SetHeight(height)

				// When the index requires all of the referenced
				// txouts they need to be retrieved from the
				// transaction index.
				var view *blockchain.UtxoViewpoint
				if indexNeedsInputs(indexer) {
					var err error
					view, err = makeUtxoView(dbTx, block)
					if err != nil {
						return err
					}
				}

				// Remove all of the index entries associated
				// with the block and update the indexer tip.
				err = dbIndexDisconnectBlock(dbTx, indexer,
					block, view)
				if err != nil {
					return err
				}

				// Update the tip to the previous block.
				hash = &block.MsgBlock().Header.PrevBlock
				height--

				return nil
			})
			if err != nil {
				return err
			}
		}

		if initialHeight != height {
			log.Infof("Removed %d orphaned blocks from %s "+
				"(heights %d to %d)", initialHeight-height,
				indexer.Name(), height+1, initialHeight)
		}
	}

	// Fetch the current tip heights for each index along with tracking the
	// lowest one so the catchup code only needs to start at the earliest
	// block and is able to skip connecting the block for the indexes that
	// don't need it.
	bestHeight := chain.BestSnapshot().Height
	lowestHeight := bestHeight
	indexerHeights := make([]int32, len(m.enabledIndexes))
	err = m.db.View(func(dbTx database.Tx) error {
		for i, indexer := range m.enabledIndexes {
			idxKey := indexer.Key()
			hash, height, err := dbFetchIndexerTip(dbTx, idxKey)
			if err != nil {
				return err
			}

			log.Debugf("Current %s tip (height %d, hash %v)",
				indexer.Name(), height, hash)
			indexerHeights[i] = height
			if height < lowestHeight {
				lowestHeight = height
			}
		}
		return nil
	})
	if err != nil {
		return err
	}

	// Nothing to index if all of the indexes are caught up.
	if lowestHeight == bestHeight {
		return nil
	}

	// Create a progress logger for the indexing process below.
	progressLogger := newBlockProgressLogger("Indexed", log)

	// At this point, one or more indexes are behind the current best chain
	// tip and need to be caught up, so log the details and loop through
	// each block that needs to be indexed.
	log.Infof("Catching up indexes from height %d to %d", lowestHeight,
		bestHeight)
	for height := lowestHeight + 1; height <= bestHeight; height++ {
		// Load the block for the height since it is required to index
		// it.
		block, err := chain.BlockByHeight(height)
		if err != nil {
			return err
		}

		// Connect the block for all indexes that need it.
		var view *blockchain.UtxoViewpoint
		for i, indexer := range m.enabledIndexes {
			// Skip indexes that don't need to be updated with this
			// block.
			if indexerHeights[i] >= height {
				continue
			}

			err := m.db.Update(func(dbTx database.Tx) error {
				// When the index requires all of the referenced
				// txouts and they haven't been loaded yet, they
				// need to be retrieved from the transaction
				// index.
				if view == nil && indexNeedsInputs(indexer) {
					var err error
					view, err = makeUtxoView(dbTx, block)
					if err != nil {
						return err
					}
				}
				return dbIndexConnectBlock(dbTx, indexer, block,
					view)
			})
			if err != nil {
				return err
			}
			indexerHeights[i] = height
		}

		// Log indexing progress.
		progressLogger.LogBlockHeight(block)
	}

	log.Infof("Indexes caught up to height %d", bestHeight)
	return nil
}