customize Blockchain code

1 files changed, 538 insertions, 0 deletions

diff --git a/core/headerchain.go b/core/headerchain.go
new file mode 100644
index 0000000..2a64763
--- /dev/null
+++ b/core/headerchain.go
@@ -0,0 +1,538 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package core
+
+import (
+	crand "crypto/rand"
+	"errors"
+	"fmt"
+	"math"
+	"math/big"
+	mrand "math/rand"
+	"sync/atomic"
+	"time"
+
+	"github.com/ava-labs/go-ethereum/common"
+	"github.com/ava-labs/go-ethereum/consensus"
+	"github.com/ava-labs/go-ethereum/core/rawdb"
+	"github.com/ava-labs/go-ethereum/core/types"
+	"github.com/ava-labs/go-ethereum/ethdb"
+	"github.com/ava-labs/go-ethereum/log"
+	"github.com/ava-labs/go-ethereum/params"
+	lru "github.com/hashicorp/golang-lru"
+)
+
+const (
+	headerCacheLimit = 512
+	tdCacheLimit     = 1024
+	numberCacheLimit = 2048
+)
+
+// HeaderChain implements the basic block header chain logic that is shared by
+// core.BlockChain and light.LightChain. It is not usable in itself, only as
+// a part of either structure.
+// It is not thread safe either, the encapsulating chain structures should do
+// the necessary mutex locking/unlocking.
+type HeaderChain struct {
+	config *params.ChainConfig
+
+	chainDb       ethdb.Database
+	genesisHeader *types.Header
+
+	currentHeader     atomic.Value // Current head of the header chain (may be above the block chain!)
+	currentHeaderHash common.Hash  // Hash of the current head of the header chain (prevent recomputing all the time)
+
+	headerCache *lru.Cache // Cache for the most recent block headers
+	tdCache     *lru.Cache // Cache for the most recent block total difficulties
+	numberCache *lru.Cache // Cache for the most recent block numbers
+
+	procInterrupt func() bool
+
+	rand   *mrand.Rand
+	engine consensus.Engine
+}
+
+// NewHeaderChain creates a new HeaderChain structure.
+//  getValidator should return the parent's validator
+//  procInterrupt points to the parent's interrupt semaphore
+//  wg points to the parent's shutdown wait group
+func NewHeaderChain(chainDb ethdb.Database, config *params.ChainConfig, engine consensus.Engine, procInterrupt func() bool) (*HeaderChain, error) {
+	headerCache, _ := lru.New(headerCacheLimit)
+	tdCache, _ := lru.New(tdCacheLimit)
+	numberCache, _ := lru.New(numberCacheLimit)
+
+	// Seed a fast but crypto originating random generator
+	seed, err := crand.Int(crand.Reader, big.NewInt(math.MaxInt64))
+	if err != nil {
+		return nil, err
+	}
+
+	hc := &HeaderChain{
+		config:        config,
+		chainDb:       chainDb,
+		headerCache:   headerCache,
+		tdCache:       tdCache,
+		numberCache:   numberCache,
+		procInterrupt: procInterrupt,
+		rand:          mrand.New(mrand.NewSource(seed.Int64())),
+		engine:        engine,
+	}
+
+	hc.genesisHeader = hc.GetHeaderByNumber(0)
+	if hc.genesisHeader == nil {
+		return nil, ErrNoGenesis
+	}
+
+	hc.currentHeader.Store(hc.genesisHeader)
+	if head := rawdb.ReadHeadBlockHash(chainDb); head != (common.Hash{}) {
+		if chead := hc.GetHeaderByHash(head); chead != nil {
+			hc.currentHeader.Store(chead)
+		}
+	}
+	hc.currentHeaderHash = hc.CurrentHeader().Hash()
+	headHeaderGauge.Update(hc.CurrentHeader().Number.Int64())
+
+	return hc, nil
+}
+
+// GetBlockNumber retrieves the block number belonging to the given hash
+// from the cache or database
+func (hc *HeaderChain) GetBlockNumber(hash common.Hash) *uint64 {
+	if cached, ok := hc.numberCache.Get(hash); ok {
+		number := cached.(uint64)
+		return &number
+	}
+	number := rawdb.ReadHeaderNumber(hc.chainDb, hash)
+	if number != nil {
+		hc.numberCache.Add(hash, *number)
+	}
+	return number
+}
+
+// WriteHeader writes a header into the local chain, given that its parent is
+// already known. If the total difficulty of the newly inserted header becomes
+// greater than the current known TD, the canonical chain is re-routed.
+//
+// Note: This method is not concurrent-safe with inserting blocks simultaneously
+// into the chain, as side effects caused by reorganisations cannot be emulated
+// without the real blocks. Hence, writing headers directly should only be done
+// in two scenarios: pure-header mode of operation (light clients), or properly
+// separated header/block phases (non-archive clients).
+func (hc *HeaderChain) WriteHeader(header *types.Header) (status WriteStatus, err error) {
+	// Cache some values to prevent constant recalculation
+	var (
+		hash   = header.Hash()
+		number = header.Number.Uint64()
+	)
+	// Calculate the total difficulty of the header
+	ptd := hc.GetTd(header.ParentHash, number-1)
+	if ptd == nil {
+		return NonStatTy, consensus.ErrUnknownAncestor
+	}
+	localTd := hc.GetTd(hc.currentHeaderHash, hc.CurrentHeader().Number.Uint64())
+	externTd := new(big.Int).Add(header.Difficulty, ptd)
+
+	// Irrelevant of the canonical status, write the td and header to the database
+	if err := hc.WriteTd(hash, number, externTd); err != nil {
+		log.Crit("Failed to write header total difficulty", "err", err)
+	}
+	rawdb.WriteHeader(hc.chainDb, header)
+
+	// If the total difficulty is higher than our known, add it to the canonical chain
+	// Second clause in the if statement reduces the vulnerability to selfish mining.
+	// Please refer to http://www.cs.cornell.edu/~ie53/publications/btcProcFC.pdf
+	if externTd.Cmp(localTd) > 0 || (externTd.Cmp(localTd) == 0 && mrand.Float64() < 0.5) {
+		// Delete any canonical number assignments above the new head
+		batch := hc.chainDb.NewBatch()
+		for i := number + 1; ; i++ {
+			hash := rawdb.ReadCanonicalHash(hc.chainDb, i)
+			if hash == (common.Hash{}) {
+				break
+			}
+			rawdb.DeleteCanonicalHash(batch, i)
+		}
+		batch.Write()
+
+		// Overwrite any stale canonical number assignments
+		var (
+			headHash   = header.ParentHash
+			headNumber = header.Number.Uint64() - 1
+			headHeader = hc.GetHeader(headHash, headNumber)
+		)
+		for rawdb.ReadCanonicalHash(hc.chainDb, headNumber) != headHash {
+			rawdb.WriteCanonicalHash(hc.chainDb, headHash, headNumber)
+
+			headHash = headHeader.ParentHash
+			headNumber = headHeader.Number.Uint64() - 1
+			headHeader = hc.GetHeader(headHash, headNumber)
+		}
+		// Extend the canonical chain with the new header
+		rawdb.WriteCanonicalHash(hc.chainDb, hash, number)
+		rawdb.WriteHeadHeaderHash(hc.chainDb, hash)
+
+		hc.currentHeaderHash = hash
+		hc.currentHeader.Store(types.CopyHeader(header))
+		headHeaderGauge.Update(header.Number.Int64())
+
+		status = CanonStatTy
+	} else {
+		status = SideStatTy
+	}
+	hc.headerCache.Add(hash, header)
+	hc.numberCache.Add(hash, number)
+
+	return
+}
+
+// WhCallback is a callback function for inserting individual headers.
+// A callback is used for two reasons: first, in a LightChain, status should be
+// processed and light chain events sent, while in a BlockChain this is not
+// necessary since chain events are sent after inserting blocks. Second, the
+// header writes should be protected by the parent chain mutex individually.
+type WhCallback func(*types.Header) error
+
+func (hc *HeaderChain) ValidateHeaderChain(chain []*types.Header, checkFreq int) (int, error) {
+	// Do a sanity check that the provided chain is actually ordered and linked
+	for i := 1; i < len(chain); i++ {
+		if chain[i].Number.Uint64() != chain[i-1].Number.Uint64()+1 || chain[i].ParentHash != chain[i-1].Hash() {
+			// Chain broke ancestry, log a message (programming error) and skip insertion
+			log.Error("Non contiguous header insert", "number", chain[i].Number, "hash", chain[i].Hash(),
+				"parent", chain[i].ParentHash, "prevnumber", chain[i-1].Number, "prevhash", chain[i-1].Hash())
+
+			return 0, fmt.Errorf("non contiguous insert: item %d is #%d [%x…], item %d is #%d [%x…] (parent [%x…])", i-1, chain[i-1].Number,
+				chain[i-1].Hash().Bytes()[:4], i, chain[i].Number, chain[i].Hash().Bytes()[:4], chain[i].ParentHash[:4])
+		}
+	}
+
+	// Generate the list of seal verification requests, and start the parallel verifier
+	seals := make([]bool, len(chain))
+	if checkFreq != 0 {
+		// In case of checkFreq == 0 all seals are left false.
+		for i := 0; i < len(seals)/checkFreq; i++ {
+			index := i*checkFreq + hc.rand.Intn(checkFreq)
+			if index >= len(seals) {
+				index = len(seals) - 1
+			}
+			seals[index] = true
+		}
+		// Last should always be verified to avoid junk.
+		seals[len(seals)-1] = true
+	}
+
+	abort, results := hc.engine.VerifyHeaders(hc, chain, seals)
+	defer close(abort)
+
+	// Iterate over the headers and ensure they all check out
+	for i, header := range chain {
+		// If the chain is terminating, stop processing blocks
+		if hc.procInterrupt() {
+			log.Debug("Premature abort during headers verification")
+			return 0, errors.New("aborted")
+		}
+		// If the header is a banned one, straight out abort
+		if BadHashes[header.Hash()] {
+			return i, ErrBlacklistedHash
+		}
+		// Otherwise wait for headers checks and ensure they pass
+		if err := <-results; err != nil {
+			return i, err
+		}
+	}
+
+	return 0, nil
+}
+
+// InsertHeaderChain attempts to insert the given header chain in to the local
+// chain, possibly creating a reorg. If an error is returned, it will return the
+// index number of the failing header as well an error describing what went wrong.
+//
+// The verify parameter can be used to fine tune whether nonce verification
+// should be done or not. The reason behind the optional check is because some
+// of the header retrieval mechanisms already need to verfy nonces, as well as
+// because nonces can be verified sparsely, not needing to check each.
+func (hc *HeaderChain) InsertHeaderChain(chain []*types.Header, writeHeader WhCallback, start time.Time) (int, error) {
+	// Collect some import statistics to report on
+	stats := struct{ processed, ignored int }{}
+	// All headers passed verification, import them into the database
+	for i, header := range chain {
+		// Short circuit insertion if shutting down
+		if hc.procInterrupt() {
+			log.Debug("Premature abort during headers import")
+			return i, errors.New("aborted")
+		}
+		// If the header's already known, skip it, otherwise store
+		hash := header.Hash()
+		if hc.HasHeader(hash, header.Number.Uint64()) {
+			externTd := hc.GetTd(hash, header.Number.Uint64())
+			localTd := hc.GetTd(hc.currentHeaderHash, hc.CurrentHeader().Number.Uint64())
+			if externTd == nil || externTd.Cmp(localTd) <= 0 {
+				stats.ignored++
+				continue
+			}
+		}
+		if err := writeHeader(header); err != nil {
+			return i, err
+		}
+		stats.processed++
+	}
+	// Report some public statistics so the user has a clue what's going on
+	last := chain[len(chain)-1]
+
+	context := []interface{}{
+		"count", stats.processed, "elapsed", common.PrettyDuration(time.Since(start)),
+		"number", last.Number, "hash", last.Hash(),
+	}
+	if timestamp := time.Unix(int64(last.Time), 0); time.Since(timestamp) > time.Minute {
+		context = append(context, []interface{}{"age", common.PrettyAge(timestamp)}...)
+	}
+	if stats.ignored > 0 {
+		context = append(context, []interface{}{"ignored", stats.ignored}...)
+	}
+	log.Info("Imported new block headers", context...)
+
+	return 0, nil
+}
+
+// GetBlockHashesFromHash retrieves a number of block hashes starting at a given
+// hash, fetching towards the genesis block.
+func (hc *HeaderChain) GetBlockHashesFromHash(hash common.Hash, max uint64) []common.Hash {
+	// Get the origin header from which to fetch
+	header := hc.GetHeaderByHash(hash)
+	if header == nil {
+		return nil
+	}
+	// Iterate the headers until enough is collected or the genesis reached
+	chain := make([]common.Hash, 0, max)
+	for i := uint64(0); i < max; i++ {
+		next := header.ParentHash
+		if header = hc.GetHeader(next, header.Number.Uint64()-1); header == nil {
+			break
+		}
+		chain = append(chain, next)
+		if header.Number.Sign() == 0 {
+			break
+		}
+	}
+	return chain
+}
+
+// GetAncestor retrieves the Nth ancestor of a given block. It assumes that either the given block or
+// a close ancestor of it is canonical. maxNonCanonical points to a downwards counter limiting the
+// number of blocks to be individually checked before we reach the canonical chain.
+//
+// Note: ancestor == 0 returns the same block, 1 returns its parent and so on.
+func (hc *HeaderChain) GetAncestor(hash common.Hash, number, ancestor uint64, maxNonCanonical *uint64) (common.Hash, uint64) {
+	if ancestor > number {
+		return common.Hash{}, 0
+	}
+	if ancestor == 1 {
+		// in this case it is cheaper to just read the header
+		if header := hc.GetHeader(hash, number); header != nil {
+			return header.ParentHash, number - 1
+		} else {
+			return common.Hash{}, 0
+		}
+	}
+	for ancestor != 0 {
+		if rawdb.ReadCanonicalHash(hc.chainDb, number) == hash {
+			number -= ancestor
+			return rawdb.ReadCanonicalHash(hc.chainDb, number), number
+		}
+		if *maxNonCanonical == 0 {
+			return common.Hash{}, 0
+		}
+		*maxNonCanonical--
+		ancestor--
+		header := hc.GetHeader(hash, number)
+		if header == nil {
+			return common.Hash{}, 0
+		}
+		hash = header.ParentHash
+		number--
+	}
+	return hash, number
+}
+
+// GetTd retrieves a block's total difficulty in the canonical chain from the
+// database by hash and number, caching it if found.
+func (hc *HeaderChain) GetTd(hash common.Hash, number uint64) *big.Int {
+	// Short circuit if the td's already in the cache, retrieve otherwise
+	if cached, ok := hc.tdCache.Get(hash); ok {
+		return cached.(*big.Int)
+	}
+	td := rawdb.ReadTd(hc.chainDb, hash, number)
+	if td == nil {
+		return nil
+	}
+	// Cache the found body for next time and return
+	hc.tdCache.Add(hash, td)
+	return td
+}
+
+// GetTdByHash retrieves a block's total difficulty in the canonical chain from the
+// database by hash, caching it if found.
+func (hc *HeaderChain) GetTdByHash(hash common.Hash) *big.Int {
+	number := hc.GetBlockNumber(hash)
+	if number == nil {
+		return nil
+	}
+	return hc.GetTd(hash, *number)
+}
+
+// WriteTd stores a block's total difficulty into the database, also caching it
+// along the way.
+func (hc *HeaderChain) WriteTd(hash common.Hash, number uint64, td *big.Int) error {
+	rawdb.WriteTd(hc.chainDb, hash, number, td)
+	hc.tdCache.Add(hash, new(big.Int).Set(td))
+	return nil
+}
+
+// GetHeader retrieves a block header from the database by hash and number,
+// caching it if found.
+func (hc *HeaderChain) GetHeader(hash common.Hash, number uint64) *types.Header {
+	// Short circuit if the header's already in the cache, retrieve otherwise
+	if header, ok := hc.headerCache.Get(hash); ok {
+		return header.(*types.Header)
+	}
+	header := rawdb.ReadHeader(hc.chainDb, hash, number)
+	if header == nil {
+		return nil
+	}
+	// Cache the found header for next time and return
+	hc.headerCache.Add(hash, header)
+	return header
+}
+
+// GetHeaderByHash retrieves a block header from the database by hash, caching it if
+// found.
+func (hc *HeaderChain) GetHeaderByHash(hash common.Hash) *types.Header {
+	number := hc.GetBlockNumber(hash)
+	if number == nil {
+		return nil
+	}
+	return hc.GetHeader(hash, *number)
+}
+
+// HasHeader checks if a block header is present in the database or not.
+func (hc *HeaderChain) HasHeader(hash common.Hash, number uint64) bool {
+	if hc.numberCache.Contains(hash) || hc.headerCache.Contains(hash) {
+		return true
+	}
+	return rawdb.HasHeader(hc.chainDb, hash, number)
+}
+
+// GetHeaderByNumber retrieves a block header from the database by number,
+// caching it (associated with its hash) if found.
+func (hc *HeaderChain) GetHeaderByNumber(number uint64) *types.Header {
+	hash := rawdb.ReadCanonicalHash(hc.chainDb, number)
+	if hash == (common.Hash{}) {
+		return nil
+	}
+	return hc.GetHeader(hash, number)
+}
+
+// CurrentHeader retrieves the current head header of the canonical chain. The
+// header is retrieved from the HeaderChain's internal cache.
+func (hc *HeaderChain) CurrentHeader() *types.Header {
+	return hc.currentHeader.Load().(*types.Header)
+}
+
+// SetCurrentHeader sets the current head header of the canonical chain.
+func (hc *HeaderChain) SetCurrentHeader(head *types.Header) {
+	rawdb.WriteHeadHeaderHash(hc.chainDb, head.Hash())
+
+	hc.currentHeader.Store(head)
+	hc.currentHeaderHash = head.Hash()
+	headHeaderGauge.Update(head.Number.Int64())
+}
+
+type (
+	// UpdateHeadBlocksCallback is a callback function that is called by SetHead
+	// before head header is updated.
+	UpdateHeadBlocksCallback func(ethdb.KeyValueWriter, *types.Header)
+
+	// DeleteBlockContentCallback is a callback function that is called by SetHead
+	// before each header is deleted.
+	DeleteBlockContentCallback func(ethdb.KeyValueWriter, common.Hash, uint64)
+)
+
+// SetHead rewinds the local chain to a new head. Everything above the new head
+// will be deleted and the new one set.
+func (hc *HeaderChain) SetHead(head uint64, updateFn UpdateHeadBlocksCallback, delFn DeleteBlockContentCallback) {
+	var (
+		parentHash common.Hash
+		batch      = hc.chainDb.NewBatch()
+	)
+	for hdr := hc.CurrentHeader(); hdr != nil && hdr.Number.Uint64() > head; hdr = hc.CurrentHeader() {
+		hash, num := hdr.Hash(), hdr.Number.Uint64()
+
+		// Rewind block chain to new head.
+		parent := hc.GetHeader(hdr.ParentHash, num-1)
+		if parent == nil {
+			parent = hc.genesisHeader
+		}
+		parentHash = hdr.ParentHash
+		// Notably, since geth has the possibility for setting the head to a low
+		// height which is even lower than ancient head.
+		// In order to ensure that the head is always no higher than the data in
+		// the database(ancient store or active store), we need to update head
+		// first then remove the relative data from the database.
+		//
+		// Update head first(head fast block, head full block) before deleting the data.
+		if updateFn != nil {
+			updateFn(hc.chainDb, parent)
+		}
+		// Update head header then.
+		rawdb.WriteHeadHeaderHash(hc.chainDb, parentHash)
+
+		// Remove the relative data from the database.
+		if delFn != nil {
+			delFn(batch, hash, num)
+		}
+		// Rewind header chain to new head.
+		rawdb.DeleteHeader(batch, hash, num)
+		rawdb.DeleteTd(batch, hash, num)
+		rawdb.DeleteCanonicalHash(batch, num)
+
+		hc.currentHeader.Store(parent)
+		hc.currentHeaderHash = parentHash
+		headHeaderGauge.Update(parent.Number.Int64())
+	}
+	batch.Write()
+
+	// Clear out any stale content from the caches
+	hc.headerCache.Purge()
+	hc.tdCache.Purge()
+	hc.numberCache.Purge()
+}
+
+// SetGenesis sets a new genesis block header for the chain
+func (hc *HeaderChain) SetGenesis(head *types.Header) {
+	hc.genesisHeader = head
+}
+
+// Config retrieves the header chain's chain configuration.
+func (hc *HeaderChain) Config() *params.ChainConfig { return hc.config }
+
+// Engine retrieves the header chain's consensus engine.
+func (hc *HeaderChain) Engine() consensus.Engine { return hc.engine }
+
+// GetBlock implements consensus.ChainReader, and returns nil for every input as
+// a header chain does not have blocks available for retrieval.
+func (hc *HeaderChain) GetBlock(hash common.Hash, number uint64) *types.Block {
+	return nil
+}