core: Hash block in Consensus.PrepareBlock. (#46)

* Add hash to block

* Check block hash in Consensus.sanityCheck

* Add hashBlockFn in block generator.go

4 files changed, 61 insertions, 33 deletions

diff --git a/core/test/blocks-generator.go b/core/test/blocks-generator.go
index 976b661..926ef5b 100644
--- a/core/test/blocks-generator.go
+++ b/core/test/blocks-generator.go
@@ -39,6 +39,8 @@ type validatorStatus struct {
 	lastAckingHeight map[types.ValidatorID]uint64
 }
 
+type hashBlockFn func(types.BlockConverter) (common.Hash, error)
+
 // getAckedBlockHash would randomly pick one block between
 // last acked one to current head.
 func (vs *validatorStatus) getAckedBlockHash(
@@ -71,9 +73,10 @@ type validatorSetStatus struct {
 	status       map[types.ValidatorID]*validatorStatus
 	validatorIDs []types.ValidatorID
 	randGen      *rand.Rand
+	hashBlock    hashBlockFn
 }
 
-func newValidatorSetStatus(vIDs []types.ValidatorID) *validatorSetStatus {
+func newValidatorSetStatus(vIDs []types.ValidatorID, hashBlock hashBlockFn) *validatorSetStatus {
 	status := make(map[types.ValidatorID]*validatorStatus)
 	for _, vID := range vIDs {
 		status[vID] = &validatorStatus{
@@ -85,6 +88,7 @@ func newValidatorSetStatus(vIDs []types.ValidatorID) *validatorSetStatus {
 		status:       status,
 		validatorIDs: vIDs,
 		randGen:      rand.New(rand.NewSource(time.Now().UnixNano())),
+		hashBlock:    hashBlock,
 	}
 }
 
@@ -139,10 +143,9 @@ func (vs *validatorSetStatus) prepareAcksForNewBlock(
 // proposeBlock propose new block and update validator status.
 func (vs *validatorSetStatus) proposeBlock(
 	proposerID types.ValidatorID,
-	acks map[common.Hash]struct{}) *types.Block {
+	acks map[common.Hash]struct{}) (*types.Block, error) {
 
 	status := vs.status[proposerID]
-	hash := common.NewRandomHash()
 	parentHash := common.Hash{}
 	if len(status.blocks) > 0 {
 		parentHash = status.blocks[len(status.blocks)-1].Hash
@@ -151,13 +154,17 @@ func (vs *validatorSetStatus) proposeBlock(
 	newBlock := &types.Block{
 		ProposerID: proposerID,
 		ParentHash: parentHash,
-		Hash:       hash,
 		Height:     uint64(len(status.blocks)),
 		Acks:       acks,
 		// TODO(mission.liao): Generate timestamp randomly.
 	}
+	var err error
+	newBlock.Hash, err = vs.hashBlock(newBlock)
+	if err != nil {
+		return nil, err
+	}
 	status.blocks = append(status.blocks, newBlock)
-	return newBlock
+	return newBlock, nil
 }
 
 // normalAckingCountGenerator would randomly pick acking count
@@ -189,17 +196,20 @@ func generateValidatorPicker() func([]types.ValidatorID) types.ValidatorID {
 // BlocksGenerator could generate blocks forming valid DAGs.
 type BlocksGenerator struct {
 	validatorPicker func([]types.ValidatorID) types.ValidatorID
+	hashBlock       hashBlockFn
 }
 
 // NewBlocksGenerator constructs BlockGenerator.
 func NewBlocksGenerator(validatorPicker func(
-	[]types.ValidatorID) types.ValidatorID) *BlocksGenerator {
+	[]types.ValidatorID) types.ValidatorID,
+	hashBlock hashBlockFn) *BlocksGenerator {
 
 	if validatorPicker == nil {
 		validatorPicker = generateValidatorPicker()
 	}
 	return &BlocksGenerator{
 		validatorPicker: validatorPicker,
+		hashBlock:       hashBlock,
 	}
 }
 
@@ -228,7 +238,7 @@ func (gen *BlocksGenerator) Generate(
 		validators = append(
 			validators, types.ValidatorID{Hash: common.NewRandomHash()})
 	}
-	status := newValidatorSetStatus(validators)
+	status := newValidatorSetStatus(validators, gen.hashBlock)
 
 	// We would record the smallest height of block that could be acked
 	// from each validator's point-of-view.
@@ -255,7 +265,11 @@ func (gen *BlocksGenerator) Generate(
 		if err != nil {
 			return
 		}
-		newBlock := status.proposeBlock(proposerID, acks)
+		var newBlock *types.Block
+		newBlock, err = status.proposeBlock(proposerID, acks)
+		if err != nil {
+			return
+		}
 
 		// Persist block to db.
 		err = writer.Put(*newBlock)
diff --git a/core/test/blocks-generator_test.go b/core/test/blocks-generator_test.go
index 84bee4c..0624da2 100644
--- a/core/test/blocks-generator_test.go
+++ b/core/test/blocks-generator_test.go
@@ -15,23 +15,6 @@
 // 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,
-// 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 test
 
 import (
@@ -52,7 +35,7 @@ func (s *BlocksGeneratorTestCase) TestGenerate() {
 	// This test case is to make sure the generated blocks are legimate.
 	validatorCount := 19
 	blockCount := 50
-	gen := NewBlocksGenerator(nil)
+	gen := NewBlocksGenerator(nil, stableRandomHash)
 	db, err := blockdb.NewMemBackedBlockDB()
 	s.Require().Nil(err)
 
diff --git a/core/test/revealer_test.go b/core/test/revealer_test.go
index 0ef19a1..8087136 100644
--- a/core/test/revealer_test.go
+++ b/core/test/revealer_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
@@ -44,7 +44,7 @@ func (s *RevealerTestSuite) SetupSuite() {
 	s.Require().Nil(err)
 
 	// Randomly generate blocks.
-	gen := NewBlocksGenerator(nil)
+	gen := NewBlocksGenerator(nil, stableRandomHash)
 	err = gen.Generate(
 		validatorCount, blockCount, nil, s.db)
 	s.Require().Nil(err)
diff --git a/core/test/utils.go b/core/test/utils.go
new file mode 100644
index 0000000..eae12a0
--- /dev/null
+++ b/core/test/utils.go
@@ -0,0 +1,31 @@
+// 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 test
+
+import (
+	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/types"
+)
+
+func stableRandomHash(blockConv types.BlockConverter) (common.Hash, error) {
+	block := blockConv.Block()
+	if (block.Hash != common.Hash{}) {
+		return block.Hash, nil
+	}
+	return common.NewRandomHash(), nil
+}