core: remove acks (#451)

8 files changed, 11 insertions, 76 deletions

diff --git a/core/db/memory_test.go b/core/db/memory_test.go
index b210c8d..b0bfb16 100644
--- a/core/db/memory_test.go
+++ b/core/db/memory_test.go
@@ -46,7 +46,6 @@ func (s *MemBackedDBTestSuite) SetupSuite() {
 		Position: types.Position{
 			Height: 0,
 		},
-		Acks: common.NewSortedHashes(common.Hashes{}),
 	}
 	s.b01 = &types.Block{
 		ProposerID: s.v0,
@@ -55,7 +54,6 @@ func (s *MemBackedDBTestSuite) SetupSuite() {
 		Position: types.Position{
 			Height: 1,
 		},
-		Acks: common.NewSortedHashes(common.Hashes{s.b00.Hash}),
 	}
 	s.b02 = &types.Block{
 		ProposerID: s.v0,
@@ -64,7 +62,6 @@ func (s *MemBackedDBTestSuite) SetupSuite() {
 		Position: types.Position{
 			Height: 2,
 		},
-		Acks: common.NewSortedHashes(common.Hashes{s.b01.Hash}),
 	}
 }
 
diff --git a/core/syncer/consensus.go b/core/syncer/consensus.go
index 538913f..7399373 100644
--- a/core/syncer/consensus.go
+++ b/core/syncer/consensus.go
@@ -337,7 +337,6 @@ func (con *Consensus) buildEmptyBlock(b *types.Block, parent *types.Block) {
 	b.Witness.Height = parent.Witness.Height
 	b.Witness.Data = make([]byte, len(parent.Witness.Data))
 	copy(b.Witness.Data, parent.Witness.Data)
-	b.Acks = common.NewSortedHashes(common.Hashes{parent.Hash})
 }
 
 // setupConfigs is called by SyncBlocks with blocks from compaction chain. In
diff --git a/core/test/block-revealer.go b/core/test/block-revealer.go
index 90b3d3e..7516e6c 100644
--- a/core/test/block-revealer.go
+++ b/core/test/block-revealer.go
@@ -31,19 +31,6 @@ 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(
-	b *types.Block, revealed map[common.Hash]struct{}) bool {
-
-	for _, ack := range b.Acks {
-		if _, exists := revealed[ack]; !exists {
-			return false
-		}
-	}
-	return true
-}
-
 // loadAllBlocks is a helper to load all blocks from db.BlockIterator.
 func loadAllBlocks(iter db.BlockIterator) (
 	blocks map[common.Hash]*types.Block, err error) {
diff --git a/core/types/block.go b/core/types/block.go
index 8c3e510..2b23e96 100644
--- a/core/types/block.go
+++ b/core/types/block.go
@@ -23,7 +23,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"sort"
 	"time"
 
 	"github.com/dexon-foundation/dexon/rlp"
@@ -125,17 +124,16 @@ type Witness struct {
 
 // Block represents a single event broadcasted on the network.
 type Block struct {
-	ProposerID   NodeID              `json:"proposer_id"`
-	ParentHash   common.Hash         `json:"parent_hash"`
-	Hash         common.Hash         `json:"hash"`
-	Position     Position            `json:"position"`
-	Timestamp    time.Time           `json:"timestamp"`
-	Acks         common.SortedHashes `json:"acks"`
-	Payload      []byte              `json:"payload"`
-	PayloadHash  common.Hash         `json:"payload_hash"`
-	Witness      Witness             `json:"witness"`
-	Finalization FinalizationResult  `json:"finalization"`
-	Signature    crypto.Signature    `json:"signature"`
+	ProposerID   NodeID             `json:"proposer_id"`
+	ParentHash   common.Hash        `json:"parent_hash"`
+	Hash         common.Hash        `json:"hash"`
+	Position     Position           `json:"position"`
+	Timestamp    time.Time          `json:"timestamp"`
+	Payload      []byte             `json:"payload"`
+	PayloadHash  common.Hash        `json:"payload_hash"`
+	Witness      Witness            `json:"witness"`
+	Finalization FinalizationResult `json:"finalization"`
+	Signature    crypto.Signature   `json:"signature"`
 
 	CRSSignature crypto.Signature `json:"crs_signature"`
 }
@@ -146,7 +144,6 @@ type rlpBlock struct {
 	Hash         common.Hash
 	Position     Position
 	Timestamp    *rlpTimestamp
-	Acks         common.SortedHashes
 	Payload      []byte
 	PayloadHash  common.Hash
 	Witness      *Witness
@@ -164,7 +161,6 @@ func (b *Block) EncodeRLP(w io.Writer) error {
 		Hash:         b.Hash,
 		Position:     b.Position,
 		Timestamp:    &rlpTimestamp{b.Timestamp},
-		Acks:         b.Acks,
 		Payload:      b.Payload,
 		PayloadHash:  b.PayloadHash,
 		Witness:      &b.Witness,
@@ -185,7 +181,6 @@ func (b *Block) DecodeRLP(s *rlp.Stream) error {
 			Hash:         dec.Hash,
 			Position:     dec.Position,
 			Timestamp:    dec.Timestamp.Time,
-			Acks:         dec.Acks,
 			Payload:      dec.Payload,
 			PayloadHash:  dec.PayloadHash,
 			Witness:      *dec.Witness,
@@ -216,8 +211,6 @@ func (b *Block) Clone() (bcopy *Block) {
 	bcopy.Witness.Data = make([]byte, len(b.Witness.Data))
 	copy(bcopy.Witness.Data, b.Witness.Data)
 	bcopy.Timestamp = b.Timestamp
-	bcopy.Acks = make(common.SortedHashes, len(b.Acks))
-	copy(bcopy.Acks, b.Acks)
 	bcopy.Payload = make([]byte, len(b.Payload))
 	copy(bcopy.Payload, b.Payload)
 	bcopy.PayloadHash = b.PayloadHash
@@ -239,14 +232,6 @@ func (b *Block) IsEmpty() bool {
 	return b.ProposerID.Hash == common.Hash{}
 }
 
-// IsAcking checks if a block acking another by it's hash.
-func (b *Block) IsAcking(hash common.Hash) bool {
-	idx := sort.Search(len(b.Acks), func(i int) bool {
-		return bytes.Compare(b.Acks[i][:], hash[:]) >= 0
-	})
-	return !(idx == len(b.Acks) || b.Acks[idx] != hash)
-}
-
 // ByHash is the helper type for sorting slice of blocks by hash.
 type ByHash []*Block
 
diff --git a/core/types/block_test.go b/core/types/block_test.go
index 1dd83a9..03eef35 100644
--- a/core/types/block_test.go
+++ b/core/types/block_test.go
@@ -70,10 +70,6 @@ func (s *BlockTestSuite) createRandomBlock() *Block {
 			Round:  rand.Uint64(),
 			Height: rand.Uint64(),
 		},
-		Acks: common.NewSortedHashes(common.Hashes{
-			common.NewRandomHash(),
-			common.NewRandomHash(),
-		}),
 		Timestamp: time.Now().UTC(),
 		Witness: Witness{
 			Height: rand.Uint64(),
@@ -180,20 +176,6 @@ func (s *BlockTestSuite) TestGenesisBlock() {
 	s.False(b2.IsGenesis())
 }
 
-func (s *BlockTestSuite) TestIsAcking() {
-	// This test case would check if types.Block.IsAcking works
-	ack0 := common.NewRandomHash()
-	acks0 := common.Hashes{
-		ack0,
-		common.NewRandomHash(),
-		common.NewRandomHash(),
-	}
-	b0 := &Block{Acks: common.NewSortedHashes(acks0)}
-	s.True(b0.IsAcking(ack0))
-	s.False(b0.IsAcking(common.Hash{}))
-	s.False(b0.IsAcking(common.NewRandomHash()))
-}
-
 func (s *BlockTestSuite) TestClone() {
 	b1 := *s.createRandomBlock()
 	b2 := *b1.Clone()
diff --git a/core/types/vote.go b/core/types/vote.go
index 6481eb4..c4a625e 100644
--- a/core/types/vote.go
+++ b/core/types/vote.go
@@ -66,7 +66,7 @@ type Vote struct {
 }
 
 func (v *Vote) String() string {
-	return fmt.Sprintf("Vote{BP:%s %s Period:%d Type:%d Hash:%s}",
+	return fmt.Sprintf("Vote{VP:%s %s Period:%d Type:%d Hash:%s}",
 		v.ProposerID.String()[:6],
 		v.Position, v.Period, v.Type, v.BlockHash.String()[:6])
 }
diff --git a/core/utils/crypto.go b/core/utils/crypto.go
index fe67a95..f5343ca 100644
--- a/core/utils/crypto.go
+++ b/core/utils/crypto.go
@@ -37,12 +37,6 @@ func hashWitness(witness *types.Witness) (common.Hash, error) {
 // HashBlock generates hash of a types.Block.
 func HashBlock(block *types.Block) (common.Hash, error) {
 	hashPosition := hashPosition(block.Position)
-	// Handling Block.Acks.
-	binaryAcks := make([][]byte, len(block.Acks))
-	for idx, ack := range block.Acks {
-		binaryAcks[idx] = ack[:]
-	}
-	hashAcks := crypto.Keccak256Hash(binaryAcks...)
 	binaryTimestamp, err := block.Timestamp.UTC().MarshalBinary()
 	if err != nil {
 		return common.Hash{}, err
@@ -56,7 +50,6 @@ func HashBlock(block *types.Block) (common.Hash, error) {
 		block.ProposerID.Hash[:],
 		block.ParentHash[:],
 		hashPosition[:],
-		hashAcks[:],
 		binaryTimestamp[:],
 		block.PayloadHash[:],
 		binaryWitness[:])
diff --git a/core/utils/crypto_test.go b/core/utils/crypto_test.go
index f1fa9b6..1077277 100644
--- a/core/utils/crypto_test.go
+++ b/core/utils/crypto_test.go
@@ -37,11 +37,9 @@ type CryptoTestSuite struct {
 var myNID = types.NodeID{Hash: common.NewRandomHash()}
 
 func (s *CryptoTestSuite) prepareBlock(prevBlock *types.Block) *types.Block {
-	acks := common.Hashes{}
 	now := time.Now().UTC()
 	if prevBlock == nil {
 		return &types.Block{
-			Acks:      common.NewSortedHashes(acks),
 			Timestamp: now,
 			Finalization: types.FinalizationResult{
 				Timestamp: time.Now(),
@@ -52,7 +50,6 @@ func (s *CryptoTestSuite) prepareBlock(prevBlock *types.Block) *types.Block {
 	s.Require().NotEqual(prevBlock.Hash, common.Hash{})
 	return &types.Block{
 		ParentHash: prevBlock.Hash,
-		Acks:       common.NewSortedHashes(acks),
 		Timestamp:  now,
 		Position: types.Position{
 			Height: prevBlock.Position.Height + 1,
@@ -116,11 +113,6 @@ func (s *CryptoTestSuite) TestBlockSignature() {
 		}
 		s.NoError(VerifyBlockSignature(block))
 	}
-	// Modify Block.Acks and verify signature again.
-	for _, block := range blocks {
-		block.Acks = append(block.Acks, common.NewRandomHash())
-		s.Error(VerifyBlockSignature(block))
-	}
 }
 
 func (s *CryptoTestSuite) TestVoteSignature() {