all, state: unexpose GenesisDoc, ChainID fields make them accessor methods

Fixes #671

Unexpose GenesisDoc and ChainID fields to avoid them being
serialized to the DB on every block write/state.Save()

A GenesisDoc can now be alternatively written to the state's
database, by serializing its JSON as a value of key "genesis-doc".

There are now accessors and a setter for these attributes:
- state.GenesisDoc() (*types.GenesisDoc, error)
- state.ChainID() (string, error)
- state.SetGenesisDoc(*types.GenesisDoc)

This is a breaking change since it changes how the state's
serialization and requires that if loading the GenesisDoc entirely
from the database, you'll need to set its value in the database
as the GenesisDoc's JSON marshaled bytes.

consensus/state.go

@@ -389,8 +389,12 @@ func (cs *ConsensusState) reconstructLastCommit(state *sm.State) {
 	if state.LastBlockHeight == 0 {
 		return
 	}
+	chainID, err := cs.state.ChainID()
+	if err != nil {
+		cmn.PanicCrisis(cmn.Fmt("Failed to retrieve ChainID: %v", err))
+	}
 	seenCommit := cs.blockStore.LoadSeenCommit(state.LastBlockHeight)
-	lastPrecommits := types.NewVoteSet(cs.state.ChainID, state.LastBlockHeight, seenCommit.Round(), types.VoteTypePrecommit, state.LastValidators)
+	lastPrecommits := types.NewVoteSet(chainID, state.LastBlockHeight, seenCommit.Round(), types.VoteTypePrecommit, state.LastValidators)
 	for _, precommit := range seenCommit.Precommits {
 		if precommit == nil {
 			continue
@@ -720,7 +724,11 @@ func (cs *ConsensusState) proposalHeartbeat(height, round int) {
 			ValidatorAddress: addr,
 			ValidatorIndex:   valIndex,
 		}
-		cs.privValidator.SignHeartbeat(cs.state.ChainID, heartbeat)
+		chainID, err := cs.state.ChainID()
+		if err != nil {
+			return
+		}
+		cs.privValidator.SignHeartbeat(chainID, heartbeat)
 		heartbeatEvent := types.EventDataProposalHeartbeat{heartbeat}
 		types.FireEventProposalHeartbeat(cs.evsw, heartbeatEvent)
 		counter += 1
@@ -797,8 +805,11 @@ func (cs *ConsensusState) defaultDecideProposal(height, round int) {
 	// Make proposal
 	polRound, polBlockID := cs.Votes.POLInfo()
 	proposal := types.NewProposal(height, round, blockParts.Header(), polRound, polBlockID)
-	err := cs.privValidator.SignProposal(cs.state.ChainID, proposal)
-	if err == nil {
+	chainID, err := cs.state.ChainID()
+	if err != nil {
+		return
+	}
+	if err := cs.privValidator.SignProposal(chainID, proposal); err == nil {
 		// Set fields
 		/*  fields set by setProposal and addBlockPart
 		cs.Proposal = proposal
@@ -857,8 +868,12 @@ func (cs *ConsensusState) createProposalBlock() (block *types.Block, blockParts
 
 	// Mempool validated transactions
 	txs := cs.mempool.Reap(cs.config.MaxBlockSizeTxs)
-
-	return types.MakeBlock(cs.Height, cs.state.ChainID, txs, commit,
+	chainID, err := cs.state.ChainID()
+	if err != nil {
+		cs.Logger.Error("chainID err", err)
+		return
+	}
+	return types.MakeBlock(cs.Height, chainID, txs, commit,
 		cs.state.LastBlockID, cs.state.Validators.Hash(),
 		cs.state.AppHash, cs.state.Params().BlockPartSizeBytes)
 }
@@ -1263,8 +1278,13 @@ func (cs *ConsensusState) defaultSetProposal(proposal *types.Proposal) error {
 		return ErrInvalidProposalPOLRound
 	}
 
+	chainID, err := cs.state.ChainID()
+	if err != nil {
+		return err
+	}
+
 	// Verify signature
-	if !cs.Validators.GetProposer().PubKey.VerifyBytes(types.SignBytes(cs.state.ChainID, proposal), proposal.Signature) {
+	if !cs.Validators.GetProposer().PubKey.VerifyBytes(types.SignBytes(chainID, proposal), proposal.Signature) {
 		return ErrInvalidProposalSignature
 	}
 
@@ -1449,6 +1469,10 @@ func (cs *ConsensusState) addVote(vote *types.Vote, peerKey string) (added bool,
 }
 
 func (cs *ConsensusState) signVote(type_ byte, hash []byte, header types.PartSetHeader) (*types.Vote, error) {
+	chainID, err := cs.state.ChainID()
+	if err != nil {
+		return nil, err
+	}
 	addr := cs.privValidator.GetAddress()
 	valIndex, _ := cs.Validators.GetByAddress(addr)
 	vote := &types.Vote{
@@ -1459,7 +1483,7 @@ func (cs *ConsensusState) signVote(type_ byte, hash []byte, header types.PartSet
 		Type:             type_,
 		BlockID:          types.BlockID{hash, header},
 	}
-	err := cs.privValidator.SignVote(cs.state.ChainID, vote)
+	err = cs.privValidator.SignVote(chainID, vote)
 	return vote, err
 }