core: syncer: add syncer (#346)

7 files changed, 136 insertions, 56 deletions

diff --git a/core/test/app.go b/core/test/app.go
index 327555b..9f030e9 100644
--- a/core/test/app.go
+++ b/core/test/app.go
@@ -280,8 +280,8 @@ Loop:
 	return nil
 }
 
-// Check provides a backdoor to check status of App with reader lock.
-func (app *App) Check(checker func(*App)) {
+// WithLock provides a backdoor to check status of App with reader lock.
+func (app *App) WithLock(function func(*App)) {
 	app.confirmedLock.RLock()
 	defer app.confirmedLock.RUnlock()
 	app.totalOrderedLock.RLock()
@@ -289,5 +289,5 @@ func (app *App) Check(checker func(*App)) {
 	app.deliveredLock.RLock()
 	defer app.deliveredLock.RUnlock()
 
-	checker(app)
+	function(app)
 }
diff --git a/core/test/fake-transport.go b/core/test/fake-transport.go
index a783ac9..388d0aa 100644
--- a/core/test/fake-transport.go
+++ b/core/test/fake-transport.go
@@ -15,23 +15,6 @@
 // along with the dexon-consensus library. If not, see
 // <http://www.gnu.org/licenses/>.
 
-// 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 test
 
 import (
diff --git a/core/test/interface.go b/core/test/interface.go
index e7a8f70..dcecee8 100644
--- a/core/test/interface.go
+++ b/core/test/interface.go
@@ -15,23 +15,6 @@
 // along with the dexon-consensus library. If not, see
 // <http://www.gnu.org/licenses/>.
 
-// 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 test
 
 import (
diff --git a/core/test/network.go b/core/test/network.go
index 8bcb050..207d8a4 100644
--- a/core/test/network.go
+++ b/core/test/network.go
@@ -437,6 +437,11 @@ func (n *Network) Broadcast(msg interface{}) {
 	}
 }
 
+// Send exports 'Send' method of Transport.
+func (n *Network) Send(nodeID types.NodeID, msg interface{}) error {
+	return n.trans.Send(nodeID, msg)
+}
+
 // ReceiveChanForNode returns a channel for messages not handled by
 // core.Consensus.
 func (n *Network) ReceiveChanForNode() <-chan interface{} {
diff --git a/core/test/revealer.go b/core/test/revealer.go
index b39a898..dcd75a5 100644
--- a/core/test/revealer.go
+++ b/core/test/revealer.go
@@ -15,26 +15,10 @@
 // along with the dexon-consensus library. If not, see
 // <http://www.gnu.org/licenses/>.
 
-// 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 test
 
 import (
+	"errors"
 	"math/rand"
 	"sort"
 	"time"
@@ -44,6 +28,11 @@ import (
 	"github.com/dexon-foundation/dexon-consensus/core/types"
 )
 
+// Errors returns from revealer.
+var (
+	ErrNotValidCompactionChain = errors.New("not valid compaction chain")
+)
+
 // isAllAckingBlockRevealed is a helper to check if all acking blocks of
 // one block are revealed.
 func isAllAckingBlockRevealed(
@@ -280,3 +269,63 @@ func (r *RandomTipRevealer) Reset() {
 		r.chainTip[i] = 0
 	}
 }
+
+// CompactionChainRevealer implements Revealer interface, which would load
+// all blocks from blockdb, reveal them in the order of compaction chain, from
+// the genesis block to the latest one.
+type CompactionChainRevealer struct {
+	blocks          types.ByFinalizationHeight
+	nextRevealIndex int
+}
+
+// NewCompactionChainRevealer constructs a revealer in the order of compaction
+// chain.
+func NewCompactionChainRevealer(iter blockdb.BlockIterator,
+	startHeight uint64) (r *CompactionChainRevealer, err error) {
+	blocksByHash, err := loadAllBlocks(iter)
+	if err != nil {
+		return
+	}
+	if startHeight == 0 {
+		startHeight = 1
+	}
+	blocks := types.ByFinalizationHeight{}
+	for _, b := range blocksByHash {
+		if b.Finalization.Height < startHeight {
+			continue
+		}
+		blocks = append(blocks, b)
+	}
+	sort.Sort(types.ByFinalizationHeight(blocks))
+	// Make sure the finalization height of blocks are incremental with step 1.
+	for idx, b := range blocks {
+		if idx == 0 {
+			continue
+		}
+		if b.Finalization.Height != blocks[idx-1].Finalization.Height+1 {
+			err = ErrNotValidCompactionChain
+			return
+		}
+	}
+	r = &CompactionChainRevealer{
+		blocks: blocks,
+	}
+	r.Reset()
+	return
+}
+
+// Next implements Revealer.Next method, which would reveal blocks in the order
+// of compaction chain.
+func (r *CompactionChainRevealer) Next() (types.Block, error) {
+	if r.nextRevealIndex == len(r.blocks) {
+		return types.Block{}, blockdb.ErrIterationFinished
+	}
+	b := r.blocks[r.nextRevealIndex]
+	r.nextRevealIndex++
+	return *b, nil
+}
+
+// Reset implement Revealer.Reset method, which would reset revealing.
+func (r *CompactionChainRevealer) Reset() {
+	r.nextRevealIndex = 0
+}
diff --git a/core/test/revealer_test.go b/core/test/revealer_test.go
index d9920c7..5a1bc07 100644
--- a/core/test/revealer_test.go
+++ b/core/test/revealer_test.go
@@ -157,6 +157,66 @@ func (s *RevealerTestSuite) TestRandomTipReveal() {
 	s.baseTest(revealer, 10, checkFunc)
 }
 
+func (s *RevealerTestSuite) TestCompactionChainReveal() {
+	db, err := blockdb.NewMemBackedBlockDB()
+	s.Require().NoError(err)
+	// Put several blocks with finalization field ready.
+	b1 := &types.Block{
+		Hash: common.NewRandomHash(),
+		Finalization: types.FinalizationResult{
+			Height: 1,
+		}}
+	b2 := &types.Block{
+		Hash: common.NewRandomHash(),
+		Finalization: types.FinalizationResult{
+			ParentHash: b1.Hash,
+			Height:     2,
+		}}
+	b3 := &types.Block{
+		Hash: common.NewRandomHash(),
+		Finalization: types.FinalizationResult{
+			ParentHash: b2.Hash,
+			Height:     3,
+		}}
+	s.Require().NoError(db.Put(*b1))
+	s.Require().NoError(db.Put(*b3))
+	iter, err := db.GetAll()
+	s.Require().NoError(err)
+	// The compaction chain is not complete, we can't construct a revealer
+	// instance successfully.
+	r, err := NewCompactionChainRevealer(iter, 0)
+	s.Require().Nil(r)
+	s.Require().IsType(ErrNotValidCompactionChain, err)
+	// Put a block to make the compaction chain complete.
+	s.Require().NoError(db.Put(*b2))
+	// We can construct that revealer now.
+	iter, err = db.GetAll()
+	s.Require().NoError(err)
+	r, err = NewCompactionChainRevealer(iter, 0)
+	s.Require().NotNil(r)
+	s.Require().NoError(err)
+	// The revealing order should be ok.
+	chk := func(h uint64) {
+		b, err := r.Next()
+		s.Require().NoError(err)
+		s.Require().Equal(b.Finalization.Height, h)
+	}
+	chk(1)
+	chk(2)
+	chk(3)
+	// Iteration should be finished
+	_, err = r.Next()
+	s.Require().IsType(blockdb.ErrIterationFinished, err)
+	// Test 'startHeight' parameter.
+	iter, err = db.GetAll()
+	s.Require().NoError(err)
+	r, err = NewCompactionChainRevealer(iter, 2)
+	s.Require().NotNil(r)
+	s.Require().NoError(err)
+	chk(2)
+	chk(3)
+}
+
 func TestRevealer(t *testing.T) {
 	suite.Run(t, new(RevealerTestSuite))
 }
diff --git a/core/test/stopper.go b/core/test/stopper.go
index abc93c3..40868d8 100644
--- a/core/test/stopper.go
+++ b/core/test/stopper.go
@@ -61,7 +61,7 @@ func (s *StopByConfirmedBlocks) ShouldStop(nID types.NodeID) bool {
 	lastChecked := s.lastCheckDelivered[nID]
 	currentConfirmedBlocks := s.confirmedBlocks[nID]
 	db := s.dbs[nID]
-	s.apps[nID].Check(func(app *App) {
+	s.apps[nID].WithLock(func(app *App) {
 		for _, h := range app.DeliverSequence[lastChecked:] {
 			b, err := db.Get(h)
 			if err != nil {
@@ -116,7 +116,7 @@ func (s *StopByRound) ShouldStop(nID types.NodeID) bool {
 	if curRound := s.currentRounds[nID]; curRound < s.untilRound {
 		lastChecked := s.lastCheckDelivered[nID]
 		db := s.dbs[nID]
-		s.apps[nID].Check(func(app *App) {
+		s.apps[nID].WithLock(func(app *App) {
 			for _, h := range app.DeliverSequence[lastChecked:] {
 				b, err := db.Get(h)
 				if err != nil {