Rebrand as tangerine-network/go-tangerine

1 files changed, 255 insertions, 0 deletions

diff --git a/vendor/github.com/byzantine-lab/dexon-consensus/core/utils.go b/vendor/github.com/byzantine-lab/dexon-consensus/core/utils.go
new file mode 100644
index 000000000..4cb3bf18a
--- /dev/null
+++ b/vendor/github.com/byzantine-lab/dexon-consensus/core/utils.go
@@ -0,0 +1,255 @@
+// Copyright 2018 The dexon-consensus Authors
+// This file is part of the dexon-consensus library.
+//
+// The dexon-consensus 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 dexon-consensus 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 dexon-consensus library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package core
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"sort"
+	"time"
+
+	"github.com/byzantine-lab/dexon-consensus/common"
+	"github.com/byzantine-lab/dexon-consensus/core/crypto"
+	"github.com/byzantine-lab/dexon-consensus/core/types"
+	"github.com/byzantine-lab/dexon-consensus/core/utils"
+)
+
+// Errors for utils.
+var (
+	ErrIncorrectVoteBlockHash = fmt.Errorf(
+		"incorrect vote block hash")
+	ErrIncorrectVoteType = fmt.Errorf(
+		"incorrect vote type")
+	ErrIncorrectVotePosition = fmt.Errorf(
+		"incorrect vote position")
+	ErrIncorrectVoteProposer = fmt.Errorf(
+		"incorrect vote proposer")
+	ErrIncorrectVotePeriod = fmt.Errorf(
+		"incorrect vote period")
+)
+
+// NodeSetCache is type alias to avoid fullnode compile error when moving
+// it to core/utils package.
+type NodeSetCache = utils.NodeSetCache
+
+// NewNodeSetCache is function alias to avoid fullnode compile error when moving
+// it to core/utils package.
+var NewNodeSetCache = utils.NewNodeSetCache
+
+var (
+	debug = false
+	// ErrEmptyTimestamps would be reported if Block.timestamps is empty.
+	ErrEmptyTimestamps = errors.New("timestamp vector should not be empty")
+)
+
+func init() {
+	if os.Getenv("DEBUG") != "" {
+		debug = true
+	}
+}
+
+// Debugf is like fmt.Printf, but only output when we are in debug mode.
+func Debugf(format string, args ...interface{}) {
+	if debug {
+		fmt.Printf(format, args...)
+	}
+}
+
+// Debugln is like fmt.Println, but only output when we are in debug mode.
+func Debugln(args ...interface{}) {
+	if debug {
+		fmt.Println(args...)
+	}
+}
+
+func interpoTime(t1 time.Time, t2 time.Time, sep int) []time.Time {
+	if sep == 0 {
+		return []time.Time{}
+	}
+	if t1.After(t2) {
+		return interpoTime(t2, t1, sep)
+	}
+	timestamps := make([]time.Time, sep)
+	duration := t2.Sub(t1)
+	period := time.Duration(
+		(duration.Nanoseconds() / int64(sep+1))) * time.Nanosecond
+	prevTime := t1
+	for idx := range timestamps {
+		prevTime = prevTime.Add(period)
+		timestamps[idx] = prevTime
+	}
+	return timestamps
+}
+
+func getMedianTime(timestamps []time.Time) (t time.Time, err error) {
+	if len(timestamps) == 0 {
+		err = ErrEmptyTimestamps
+		return
+	}
+	tscopy := make([]time.Time, 0, len(timestamps))
+	for _, ts := range timestamps {
+		tscopy = append(tscopy, ts)
+	}
+	sort.Sort(common.ByTime(tscopy))
+	if len(tscopy)%2 == 0 {
+		t1 := tscopy[len(tscopy)/2-1]
+		t2 := tscopy[len(tscopy)/2]
+		t = interpoTime(t1, t2, 1)[0]
+	} else {
+		t = tscopy[len(tscopy)/2]
+	}
+	return
+}
+
+func removeFromSortedUint32Slice(xs []uint32, x uint32) []uint32 {
+	indexToRemove := sort.Search(len(xs), func(idx int) bool {
+		return xs[idx] >= x
+	})
+	if indexToRemove == len(xs) || xs[indexToRemove] != x {
+		// This value is not found.
+		return xs
+	}
+	return append(xs[:indexToRemove], xs[indexToRemove+1:]...)
+}
+
+// HashConfigurationBlock returns the hash value of configuration block.
+func HashConfigurationBlock(
+	notarySet map[types.NodeID]struct{},
+	config *types.Config,
+	snapshotHash common.Hash,
+	prevHash common.Hash,
+) common.Hash {
+	notaryIDs := make(types.NodeIDs, 0, len(notarySet))
+	for nID := range notarySet {
+		notaryIDs = append(notaryIDs, nID)
+	}
+	sort.Sort(notaryIDs)
+	notarySetBytes := make([]byte, 0, len(notarySet)*len(common.Hash{}))
+	for _, nID := range notaryIDs {
+		notarySetBytes = append(notarySetBytes, nID.Hash[:]...)
+	}
+	configBytes := config.Bytes()
+
+	return crypto.Keccak256Hash(
+		notarySetBytes[:],
+		configBytes[:],
+		snapshotHash[:],
+		prevHash[:],
+	)
+}
+
+// VerifyAgreementResult perform sanity check against a types.AgreementResult
+// instance.
+func VerifyAgreementResult(
+	res *types.AgreementResult, cache *NodeSetCache) error {
+	if res.Position.Round >= DKGDelayRound {
+		if len(res.Randomness) == 0 {
+			return ErrMissingRandomness
+		}
+		return nil
+	}
+	notarySet, err := cache.GetNotarySet(res.Position.Round)
+	if err != nil {
+		return err
+	}
+	if len(res.Votes) < len(notarySet)*2/3+1 {
+		return ErrNotEnoughVotes
+	}
+	voted := make(map[types.NodeID]struct{}, len(notarySet))
+	voteType := res.Votes[0].Type
+	votePeriod := res.Votes[0].Period
+	if voteType != types.VoteFastCom && voteType != types.VoteCom {
+		return ErrIncorrectVoteType
+	}
+	for _, vote := range res.Votes {
+		if vote.Period != votePeriod {
+			return ErrIncorrectVotePeriod
+		}
+		if res.IsEmptyBlock {
+			if (vote.BlockHash != common.Hash{}) {
+				return ErrIncorrectVoteBlockHash
+			}
+		} else {
+			if vote.BlockHash != res.BlockHash {
+				return ErrIncorrectVoteBlockHash
+			}
+		}
+		if vote.Type != voteType {
+			return ErrIncorrectVoteType
+		}
+		if vote.Position != res.Position {
+			return ErrIncorrectVotePosition
+		}
+		if _, exist := notarySet[vote.ProposerID]; !exist {
+			return ErrIncorrectVoteProposer
+		}
+		ok, err := utils.VerifyVoteSignature(&vote)
+		if err != nil {
+			return err
+		}
+		if !ok {
+			return ErrIncorrectVoteSignature
+		}
+		voted[vote.ProposerID] = struct{}{}
+	}
+	if len(voted) < len(notarySet)*2/3+1 {
+		return ErrNotEnoughVotes
+	}
+	return nil
+}
+
+// DiffUint64 calculates difference between two uint64.
+func DiffUint64(a, b uint64) uint64 {
+	if a > b {
+		return a - b
+	}
+	return b - a
+}
+
+func isCI() bool {
+	return os.Getenv("CI") != ""
+}
+
+func isCircleCI() bool {
+	return isCI() && os.Getenv("CIRCLECI") == "true"
+}
+
+func isTravisCI() bool {
+	return isCI() && os.Getenv("TRAVIS") == "true"
+}
+
+// checkWithCancel is a helper to perform periodic checking with cancel.
+func checkWithCancel(parentCtx context.Context, interval time.Duration,
+	checker func() bool) (ret bool) {
+	ctx, cancel := context.WithCancel(parentCtx)
+	defer cancel()
+Loop:
+	for {
+		if ret = checker(); ret {
+			return
+		}
+		select {
+		case <-ctx.Done():
+			break Loop
+		case <-time.After(interval):
+		}
+	}
+	return
+}