core: Add Block.IsGenesis() and set Block.ParentHash to 0 in genesis block. (#37)

9 files changed, 109 insertions, 113 deletions

diff --git a/core/consensus_test.go b/core/consensus_test.go
index 7ce06e9..1544818 100644
--- a/core/consensus_test.go
+++ b/core/consensus_test.go
@@ -40,7 +40,7 @@ func (s *ConsensusTestSuite) prepareGenesisBlock(
 	hash := common.NewRandomHash()
 	block := &types.Block{
 		ProposerID: proposerID,
-		ParentHash: hash,
+		ParentHash: common.Hash{},
 		Hash:       hash,
 		Height:     0,
 		Acks:       make(map[common.Hash]struct{}),
diff --git a/core/reliable-broadcast.go b/core/reliable-broadcast.go
index 7db8212..e7ae9e7 100644
--- a/core/reliable-broadcast.go
+++ b/core/reliable-broadcast.go
@@ -1,15 +1,15 @@
 // 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
+// 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.
+// 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
@@ -304,7 +304,6 @@ func (rb *reliableBroadcast) extractBlocks() []*types.Block {
 func (rb *reliableBroadcast) prepareBlock(block *types.Block) {
 	// Reset fields to make sure we got these information from parent block.
 	block.Height = 0
-	// TODO(mission): make all genesis block would contain zero ParentHash.
 	block.ParentHash = common.Hash{}
 	// The helper function to accumulate timestamps.
 	accumulateTimestamps := func(
diff --git a/core/reliable-broadcast_test.go b/core/reliable-broadcast_test.go
index bd77ea3..220a997 100644
--- a/core/reliable-broadcast_test.go
+++ b/core/reliable-broadcast_test.go
@@ -1,15 +1,15 @@
 // 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
+// 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.
+// 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
@@ -49,11 +49,10 @@ func (s *ReliableBroadcastTest) prepareGenesisBlock(
 	proposerID types.ValidatorID,
 	validatorIDs []types.ValidatorID) (b *types.Block) {
 
-	hash := common.NewRandomHash()
 	b = &types.Block{
 		ProposerID: proposerID,
-		ParentHash: hash,
-		Hash:       hash,
+		ParentHash: common.Hash{},
+		Hash:       common.NewRandomHash(),
 		Height:     0,
 		Acks:       make(map[common.Hash]struct{}),
 		Timestamps: make(map[types.ValidatorID]time.Time),
@@ -85,15 +84,8 @@ func genTestCase1(s *ReliableBroadcastTest, r *reliableBroadcast) []types.Valida
 		vids = append(vids, vid)
 	}
 	// Add genesis blocks.
-	for i := 0; i < 4; i++ {
-		h = common.NewRandomHash()
-		b = &types.Block{
-			ProposerID: vids[i],
-			ParentHash: h,
-			Hash:       h,
-			Height:     0,
-			Acks:       map[common.Hash]struct{}{},
-		}
+	for _, vid := range vids {
+		b = s.prepareGenesisBlock(vid, vids)
 		r.processBlock(b)
 	}
 
@@ -401,19 +393,15 @@ func (s *ReliableBroadcastTest) TestRandomIntensiveAcking() {
 	heights := map[types.ValidatorID]uint64{}
 	extractedBlocks := []*types.Block{}
 
-	// Generate validators and genesis blocks.
+	// Generate validators.
 	for i := 0; i < 4; i++ {
 		vid := types.ValidatorID{Hash: common.NewRandomHash()}
 		r.addValidator(vid)
 		vids = append(vids, vid)
-		h := common.NewRandomHash()
-		b := &types.Block{
-			Hash:       h,
-			ParentHash: h,
-			Acks:       map[common.Hash]struct{}{},
-			Height:     0,
-			ProposerID: vid,
-		}
+	}
+	// Generate genesis blocks.
+	for _, vid := range vids {
+		b := s.prepareGenesisBlock(vid, vids)
 		r.processBlock(b)
 		heights[vid] = 1
 	}
diff --git a/core/test/blocks-generator.go b/core/test/blocks-generator.go
index ae41757..976b661 100644
--- a/core/test/blocks-generator.go
+++ b/core/test/blocks-generator.go
@@ -1,15 +1,15 @@
 // 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
+// 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.
+// 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
@@ -143,7 +143,7 @@ func (vs *validatorSetStatus) proposeBlock(
 
 	status := vs.status[proposerID]
 	hash := common.NewRandomHash()
-	parentHash := hash
+	parentHash := common.Hash{}
 	if len(status.blocks) > 0 {
 		parentHash = status.blocks[len(status.blocks)-1].Hash
 	}
diff --git a/core/test/blocks-generator_test.go b/core/test/blocks-generator_test.go
index b9c0b35..84bee4c 100644
--- a/core/test/blocks-generator_test.go
+++ b/core/test/blocks-generator_test.go
@@ -1,6 +1,23 @@
 // 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/>.
+
+// 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,
@@ -72,7 +89,7 @@ func (s *BlocksGeneratorTestCase) TestGenerate() {
 
 		// Check genesis block.
 		genesisBlock := blocks[0]
-		s.Equal(genesisBlock.Hash, genesisBlock.ParentHash)
+		s.Equal(genesisBlock.ParentHash, common.Hash{})
 		s.Equal(genesisBlock.Height, uint64(0))
 		s.Empty(genesisBlock.Acks)
 
diff --git a/core/total-ordering_test.go b/core/total-ordering_test.go
index b4fe13c..78b4d96 100644
--- a/core/total-ordering_test.go
+++ b/core/total-ordering_test.go
@@ -1,15 +1,15 @@
 // 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
+// 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.
+// 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
@@ -45,14 +45,13 @@ func (s *TotalOrderingTestSuite) generateValidatorIDs(
 	return validatorIDs
 }
 
-func (s *TotalOrderingTestSuite) genRootBlock(
+func (s *TotalOrderingTestSuite) genGenesisBlock(
 	vID types.ValidatorID, acks map[common.Hash]struct{}) *types.Block {
 
-	hash := common.NewRandomHash()
 	return &types.Block{
 		ProposerID: vID,
-		ParentHash: hash,
-		Hash:       hash,
+		ParentHash: common.Hash{},
+		Hash:       common.NewRandomHash(),
 		Height:     0,
 		Acks:       acks,
 	}
@@ -88,14 +87,7 @@ func (s *TotalOrderingTestSuite) TestBlockRelation() {
 
 	vID := types.ValidatorID{Hash: common.NewRandomHash()}
 
-	hash := common.NewRandomHash()
-	blockA := &types.Block{
-		ProposerID: vID,
-		ParentHash: hash,
-		Hash:       hash,
-		Height:     0,
-		Acks:       map[common.Hash]struct{}{},
-	}
+	blockA := s.genGenesisBlock(vID, map[common.Hash]struct{}{})
 	blockB := &types.Block{
 		ProposerID: vID,
 		ParentHash: blockA.Hash,
@@ -243,16 +235,9 @@ func (s *TotalOrderingTestSuite) TestCycleDetection() {
 
 	// create blocks with cycles in acking relation.
 	cycledHash := common.NewRandomHash()
-	hash := common.NewRandomHash()
-	b00 := &types.Block{
-		ProposerID: validators[0],
-		ParentHash: hash,
-		Hash:       hash,
-		Height:     0,
-		Acks: map[common.Hash]struct{}{
-			cycledHash: struct{}{},
-		},
-	}
+	b00 := s.genGenesisBlock(validators[0], map[common.Hash]struct{}{
+		cycledHash: struct{}{},
+	})
 	b01 := &types.Block{
 		ProposerID: validators[0],
 		ParentHash: b00.Hash,
@@ -282,16 +267,8 @@ func (s *TotalOrderingTestSuite) TestCycleDetection() {
 	}
 
 	// Create a block acks self.
-	hash = common.NewRandomHash()
-	b10 := &types.Block{
-		ProposerID: validators[1],
-		ParentHash: hash,
-		Hash:       hash,
-		Height:     0,
-		Acks: map[common.Hash]struct{}{
-			hash: struct{}{},
-		},
-	}
+	b10 := s.genGenesisBlock(validators[1], map[common.Hash]struct{}{})
+	b10.Acks[b10.Hash] = struct{}{}
 
 	// Make sure we won't hang when cycle exists.
 	to := newTotalOrdering(1, 3, 5)
@@ -309,14 +286,7 @@ func (s *TotalOrderingTestSuite) TestNotValidDAGDetection() {
 	validators := s.generateValidatorIDs(4)
 	to := newTotalOrdering(1, 3, 5)
 
-	hash := common.NewRandomHash()
-	b00 := &types.Block{
-		ProposerID: validators[0],
-		ParentHash: hash,
-		Hash:       hash,
-		Height:     0,
-		Acks:       map[common.Hash]struct{}{},
-	}
+	b00 := s.genGenesisBlock(validators[0], map[common.Hash]struct{}{})
 	b01 := &types.Block{
 		ProposerID: validators[0],
 		ParentHash: b00.Hash,
@@ -356,23 +326,23 @@ func (s *TotalOrderingTestSuite) TestEarlyDeliver() {
 		}
 	}
 
-	b00 := s.genRootBlock(validators[0], map[common.Hash]struct{}{})
+	b00 := s.genGenesisBlock(validators[0], map[common.Hash]struct{}{})
 	b01 := genNextBlock(b00)
 	b02 := genNextBlock(b01)
 
-	b10 := s.genRootBlock(validators[1], map[common.Hash]struct{}{
+	b10 := s.genGenesisBlock(validators[1], map[common.Hash]struct{}{
 		b00.Hash: struct{}{},
 	})
 	b11 := genNextBlock(b10)
 	b12 := genNextBlock(b11)
 
-	b20 := s.genRootBlock(validators[2], map[common.Hash]struct{}{
+	b20 := s.genGenesisBlock(validators[2], map[common.Hash]struct{}{
 		b00.Hash: struct{}{},
 	})
 	b21 := genNextBlock(b20)
 	b22 := genNextBlock(b21)
 
-	b30 := s.genRootBlock(validators[3], map[common.Hash]struct{}{
+	b30 := s.genGenesisBlock(validators[3], map[common.Hash]struct{}{
 		b00.Hash: struct{}{},
 	})
 	b31 := genNextBlock(b30)
@@ -460,13 +430,13 @@ func (s *TotalOrderingTestSuite) TestBasicCaseForK2() {
 	to := newTotalOrdering(2, 3, 5)
 	validators := s.generateValidatorIDs(5)
 
-	b00 := s.genRootBlock(validators[0], map[common.Hash]struct{}{})
-	b10 := s.genRootBlock(validators[1], map[common.Hash]struct{}{})
-	b20 := s.genRootBlock(
+	b00 := s.genGenesisBlock(validators[0], map[common.Hash]struct{}{})
+	b10 := s.genGenesisBlock(validators[1], map[common.Hash]struct{}{})
+	b20 := s.genGenesisBlock(
 		validators[2], map[common.Hash]struct{}{b10.Hash: struct{}{}})
-	b30 := s.genRootBlock(
+	b30 := s.genGenesisBlock(
 		validators[3], map[common.Hash]struct{}{b20.Hash: struct{}{}})
-	b40 := s.genRootBlock(validators[4], map[common.Hash]struct{}{})
+	b40 := s.genGenesisBlock(validators[4], map[common.Hash]struct{}{})
 	b11 := &types.Block{
 		ProposerID: validators[1],
 		ParentHash: b10.Hash,
@@ -791,10 +761,10 @@ func (s *TotalOrderingTestSuite) TestBasicCaseForK0() {
 	to := newTotalOrdering(0, 3, 5)
 	validators := s.generateValidatorIDs(5)
 
-	b00 := s.genRootBlock(validators[0], map[common.Hash]struct{}{})
-	b10 := s.genRootBlock(validators[1], map[common.Hash]struct{}{})
-	b20 := s.genRootBlock(validators[2], map[common.Hash]struct{}{})
-	b30 := s.genRootBlock(validators[3], map[common.Hash]struct{}{
+	b00 := s.genGenesisBlock(validators[0], map[common.Hash]struct{}{})
+	b10 := s.genGenesisBlock(validators[1], map[common.Hash]struct{}{})
+	b20 := s.genGenesisBlock(validators[2], map[common.Hash]struct{}{})
+	b30 := s.genGenesisBlock(validators[3], map[common.Hash]struct{}{
 		b20.Hash: struct{}{},
 	})
 	b01 := &types.Block{
@@ -836,7 +806,7 @@ func (s *TotalOrderingTestSuite) TestBasicCaseForK0() {
 			b30.Hash: struct{}{},
 		},
 	}
-	b40 := s.genRootBlock(validators[4], map[common.Hash]struct{}{
+	b40 := s.genGenesisBlock(validators[4], map[common.Hash]struct{}{
 		b31.Hash: struct{}{},
 	})
 
diff --git a/core/types/block.go b/core/types/block.go
index 55e82da..e35ab8d 100644
--- a/core/types/block.go
+++ b/core/types/block.go
@@ -111,6 +111,11 @@ func (b *Block) Clone() *Block {
 	return bcopy
 }
 
+// IsGenesis checks if the block is a genesisBlock
+func (b *Block) IsGenesis() bool {
+	return b.Height == 0 && b.ParentHash == common.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 8297508..2087373 100644
--- a/core/types/block_test.go
+++ b/core/types/block_test.go
@@ -1,15 +1,15 @@
 // 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
+// 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.
+// 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
@@ -62,6 +62,24 @@ func (s *BlockTestSuite) TestSortByHeight() {
 	s.Equal(blocks[3].Hash, b3.Hash)
 }
 
+func (s *BlockTestSuite) TestGenesisBlock() {
+	b0 := &Block{
+		Height:     0,
+		ParentHash: common.Hash{},
+	}
+	s.True(b0.IsGenesis())
+	b1 := &Block{
+		Height:     1,
+		ParentHash: common.Hash{},
+	}
+	s.False(b1.IsGenesis())
+	b2 := &Block{
+		Height:     0,
+		ParentHash: common.NewRandomHash(),
+	}
+	s.False(b2.IsGenesis())
+}
+
 func TestBlock(t *testing.T) {
 	suite.Run(t, new(BlockTestSuite))
 }
diff --git a/simulation/validator.go b/simulation/validator.go
index a30420e..b4e6127 100644
--- a/simulation/validator.go
+++ b/simulation/validator.go
@@ -135,7 +135,7 @@ func (v *Validator) MsgServer(isStopped chan struct{}) {
 				}
 			} else {
 				pendingBlocks = append(pendingBlocks, val)
-				if val.ParentHash == val.Hash {
+				if val.IsGenesis() {
 					v.gov.addValidator(val.ProposerID)
 				}
 				validatorSet := v.gov.GetValidatorSet()
@@ -162,11 +162,10 @@ func (v *Validator) BroadcastGenesisBlock() {
 	for v.network.NumPeers() != v.config.Num {
 		time.Sleep(time.Second)
 	}
-	hash := common.NewRandomHash()
 	b := &types.Block{
 		ProposerID: v.ID,
-		ParentHash: hash,
-		Hash:       hash,
+		ParentHash: common.Hash{},
+		Hash:       common.NewRandomHash(),
 		Height:     0,
 		Acks:       map[common.Hash]struct{}{},
 		Timestamps: map[types.ValidatorID]time.Time{