core: Add a new structure `Position` and move `ShardID`, `ChainID` and `Height` from `Block` (#89)

4 files changed, 56 insertions, 21 deletions

diff --git a/core/types/block.go b/core/types/block.go
index f13d868..ab2ef84 100644
--- a/core/types/block.go
+++ b/core/types/block.go
@@ -65,9 +65,7 @@ type Block struct {
 	ProposerID ValidatorID               `json:"proposer_id"`
 	ParentHash common.Hash               `json:"parent_hash"`
 	Hash       common.Hash               `json:"hash"`
-	ShardID    uint64                    `json:"shard_id"`
-	ChainID    uint64                    `json:"chain_id"`
-	Height     uint64                    `json:"height"`
+	Position   Position                  `json:"position"`
 	Timestamps map[ValidatorID]time.Time `json:"timestamps"`
 	Acks       map[common.Hash]struct{}  `json:"acks"`
 	Payloads   [][]byte                  `json:"payloads"`
@@ -88,9 +86,9 @@ func (b *Block) Clone() (bcopy *Block) {
 	bcopy.ProposerID = b.ProposerID
 	bcopy.ParentHash = b.ParentHash
 	bcopy.Hash = b.Hash
-	bcopy.ShardID = b.ShardID
-	bcopy.ChainID = b.ChainID
-	bcopy.Height = b.Height
+	bcopy.Position.ShardID = b.Position.ShardID
+	bcopy.Position.ChainID = b.Position.ChainID
+	bcopy.Position.Height = b.Position.Height
 	bcopy.Signature = b.Signature.Clone()
 	bcopy.CRSSignature = b.CRSSignature.Clone()
 	bcopy.Notary.Timestamp = b.Notary.Timestamp
@@ -118,7 +116,7 @@ func (b *Block) Clone() (bcopy *Block) {
 
 // IsGenesis checks if the block is a genesisBlock
 func (b *Block) IsGenesis() bool {
-	return b.Height == 0 && b.ParentHash == common.Hash{}
+	return b.Position.Height == 0 && b.ParentHash == common.Hash{}
 }
 
 // ByHash is the helper type for sorting slice of blocks by hash.
@@ -144,7 +142,7 @@ func (b ByHeight) Len() int {
 }
 
 func (b ByHeight) Less(i int, j int) bool {
-	return b[i].Height < b[j].Height
+	return b[i].Position.Height < b[j].Position.Height
 }
 
 func (b ByHeight) Swap(i int, j int) {
diff --git a/core/types/block_test.go b/core/types/block_test.go
index 2087373..4763ad1 100644
--- a/core/types/block_test.go
+++ b/core/types/block_test.go
@@ -49,10 +49,10 @@ func (s *BlockTestSuite) TestSortByHash() {
 }
 
 func (s *BlockTestSuite) TestSortByHeight() {
-	b0 := &Block{Height: 0}
-	b1 := &Block{Height: 1}
-	b2 := &Block{Height: 2}
-	b3 := &Block{Height: 3}
+	b0 := &Block{Position: Position{Height: 0}}
+	b1 := &Block{Position: Position{Height: 1}}
+	b2 := &Block{Position: Position{Height: 2}}
+	b3 := &Block{Position: Position{Height: 3}}
 
 	blocks := []*Block{b3, b2, b1, b0}
 	sort.Sort(ByHeight(blocks))
@@ -64,17 +64,23 @@ func (s *BlockTestSuite) TestSortByHeight() {
 
 func (s *BlockTestSuite) TestGenesisBlock() {
 	b0 := &Block{
-		Height:     0,
+		Position: Position{
+			Height: 0,
+		},
 		ParentHash: common.Hash{},
 	}
 	s.True(b0.IsGenesis())
 	b1 := &Block{
-		Height:     1,
+		Position: Position{
+			Height: 1,
+		},
 		ParentHash: common.Hash{},
 	}
 	s.False(b1.IsGenesis())
 	b2 := &Block{
-		Height:     0,
+		Position: Position{
+			Height: 0,
+		},
 		ParentHash: common.NewRandomHash(),
 	}
 	s.False(b2.IsGenesis())
diff --git a/core/types/position.go b/core/types/position.go
new file mode 100644
index 0000000..a894c4b
--- /dev/null
+++ b/core/types/position.go
@@ -0,0 +1,25 @@
+// Copyright 2018 The dexon-consensus-core Authors
+// This file is part of the dexon-consensus-core library.
+//
+// The dexon-consensus-core 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-core 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-core library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package types
+
+// Position describes the position in the block lattice of an entity.
+type Position struct {
+	ShardID uint32 `json:"shard_id"`
+	ChainID uint32 `json:"chain_id"`
+	Height  uint64 `json:"height"`
+}
diff --git a/core/types/vote.go b/core/types/vote.go
index 1247f84..158c209 100644
--- a/core/types/vote.go
+++ b/core/types/vote.go
@@ -38,11 +38,12 @@ const (
 
 // Vote is the vote structure defined in Crypto Shuffle Algorithm.
 type Vote struct {
-	ProposerID ValidatorID
-	Type       VoteType
-	BlockHash  common.Hash
-	Period     uint64
-	Signature  crypto.Signature
+	ProposerID ValidatorID      `json:"proposer_id"`
+	Type       VoteType         `json:"type"`
+	BlockHash  common.Hash      `json:"block_hash"`
+	Period     uint64           `json:"period"`
+	Position   Position         `json:"position"`
+	Signature  crypto.Signature `json:"signature"`
 }
 
 func (v *Vote) String() string {
@@ -57,6 +58,11 @@ func (v *Vote) Clone() *Vote {
 		Type:       v.Type,
 		BlockHash:  v.BlockHash,
 		Period:     v.Period,
-		Signature:  v.Signature.Clone(),
+		Position: Position{
+			ShardID: v.Position.ShardID,
+			ChainID: v.Position.ChainID,
+			Height:  v.Position.Height,
+		},
+		Signature: v.Signature.Clone(),
 	}
 }