Add initial DEXON consensus engine implementation skeleton

5 files changed, 178 insertions, 3 deletions

diff --git a/consensus/dexcon/api.go b/consensus/dexcon/api.go
new file mode 100644
index 000000000..6f314b96b
--- /dev/null
+++ b/consensus/dexcon/api.go
@@ -0,0 +1,26 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum 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 go-ethereum 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 go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package dexcon
+
+// API exposes ethash related methods for the RPC interface.
+type API struct {
+	dexcon *Dexcon
+}
+
+func (api *API) Hello() error {
+	return nil
+}
diff --git a/consensus/dexcon/dexcon.go b/consensus/dexcon/dexcon.go
new file mode 100644
index 000000000..bbdd06ed8
--- /dev/null
+++ b/consensus/dexcon/dexcon.go
@@ -0,0 +1,133 @@
+// Copyright 2017 The DEXON Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum 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 go-ethereum 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 go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package dexcon
+
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus"
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/params"
+	"github.com/ethereum/go-ethereum/rpc"
+)
+
+// Dexcon is a delegated proof-of-stake consensus engine.
+type Dexcon struct {
+	config *params.DexconConfig
+}
+
+// New creates a Clique proof-of-authority consensus engine with the initial
+// signers set to the ones provided by the user.
+func New(config *params.DexconConfig) *Dexcon {
+	return &Dexcon{
+		config: config,
+	}
+}
+
+// Author implements consensus.Engine, returning the Ethereum address recovered
+// from the signature in the header's extra-data section.
+func (d *Dexcon) Author(header *types.Header) (common.Address, error) {
+	return common.Address{}, nil
+}
+
+// VerifyHeader checks whether a header conforms to the consensus rules.
+func (d *Dexcon) VerifyHeader(chain consensus.ChainReader, header *types.Header, seal bool) error {
+	return nil
+}
+
+// VerifyHeaders is similar to VerifyHeader, but verifies a batch of headers. The
+// method returns a quit channel to abort the operations and a results channel to
+// retrieve the async verifications (the order is that of the input slice).
+func (d *Dexcon) VerifyHeaders(chain consensus.ChainReader, headers []*types.Header, seals []bool) (chan<- struct{}, <-chan error) {
+	return make(chan struct{}), make(chan error)
+}
+
+// verifyHeader checks whether a header conforms to the consensus rules.The
+// caller may optionally pass in a batch of parents (ascending order) to avoid
+// looking those up from the database. This is useful for concurrently verifying
+// a batch of new headers.
+func (d *Dexcon) verifyHeader(chain consensus.ChainReader, header *types.Header, parents []*types.Header) error {
+	return nil
+}
+
+// verifyCascadingFields verifies all the header fields that are not standalone,
+// rather depend on a batch of previous headers. The caller may optionally pass
+// in a batch of parents (ascending order) to avoid looking those up from the
+// database. This is useful for concurrently verifying a batch of new headers.
+func (d *Dexcon) verifyCascadingFields(chain consensus.ChainReader, header *types.Header, parents []*types.Header) error {
+	return nil
+}
+
+// VerifyUncles implements consensus.Engine, always returning an error for any
+// uncles as this consensus mechanism doesn't permit uncles.
+func (d *Dexcon) VerifyUncles(chain consensus.ChainReader, block *types.Block) error {
+	return nil
+}
+
+// VerifySeal implements consensus.Engine, checking whether the signature contained
+// in the header satisfies the consensus protocol requirements.
+func (d *Dexcon) VerifySeal(chain consensus.ChainReader, header *types.Header) error {
+	return nil
+}
+
+// Prepare implements consensus.Engine, preparing all the consensus fields of the
+// header for running the transactions on top.
+func (d *Dexcon) Prepare(chain consensus.ChainReader, header *types.Header) error {
+	return nil
+}
+
+// Finalize implements consensus.Engine, ensuring no uncles are set, nor block
+// rewards given, and returns the final block.
+func (d *Dexcon) Finalize(chain consensus.ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction, uncles []*types.Header, receipts []*types.Receipt) (*types.Block, error) {
+	return nil, nil
+}
+
+// Seal implements consensus.Engine, attempting to create a sealed block using
+// the local signing credentials.
+func (d *Dexcon) Seal(chain consensus.ChainReader, block *types.Block, results chan<- *types.Block, stop <-chan struct{}) error {
+	return nil
+}
+
+// SealHash returns the hash of a block prior to it being sealed.
+func (d *Dexcon) SealHash(header *types.Header) (hash common.Hash) {
+	return common.Hash{}
+}
+
+// CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
+// that a new block should have based on the previous blocks in the chain and the
+// current signer.
+func (d *Dexcon) CalcDifficulty(chain consensus.ChainReader, time uint64, parent *types.Header) *big.Int {
+	return big.NewInt(0)
+}
+
+// Close implements consensus.Engine. It's a noop for clique as there is are no background threads.
+func (d *Dexcon) Close() error {
+	return nil
+}
+
+// APIs implements consensus.Engine, returning the user facing RPC API to allow
+// controlling the signer voting.
+func (d *Dexcon) APIs(chain consensus.ChainReader) []rpc.API {
+	return []rpc.API{{
+		Namespace: "dexcon",
+		Version:   "1.0",
+		Service:   &API{dexcon: d},
+		Public:    false,
+	}}
+}
diff --git a/eth/backend.go b/eth/backend.go
index 2a9d56c5c..19f48662d 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -30,6 +30,7 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/consensus/clique"
+	"github.com/ethereum/go-ethereum/consensus/dexcon"
 	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/bloombits"
@@ -224,6 +225,10 @@ func CreateDB(ctx *node.ServiceContext, config *Config, name string) (ethdb.Data
 // CreateConsensusEngine creates the required type of consensus engine instance for an Ethereum service
 func CreateConsensusEngine(ctx *node.ServiceContext, chainConfig *params.ChainConfig, config *ethash.Config, notify []string, noverify bool, db ethdb.Database) consensus.Engine {
 	// If proof-of-authority is requested, set it up
+	if chainConfig.Dexcon != nil {
+		return dexcon.New(chainConfig.Dexcon)
+	}
+	// If proof-of-authority is requested, set it up
 	if chainConfig.Clique != nil {
 		return clique.New(chainConfig.Clique, db)
 	}
diff --git a/params/config.go b/params/config.go
index 254508c0a..3cf86e9be 100644
--- a/params/config.go
+++ b/params/config.go
@@ -142,16 +142,16 @@ var (
 	//
 	// This configuration is intentionally not using keyed fields to force anyone
 	// adding flags to the config to also have to set these fields.
-	AllEthashProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil}
+	AllEthashProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil, nil}
 
 	// AllCliqueProtocolChanges contains every protocol change (EIPs) introduced
 	// and accepted by the Ethereum core developers into the Clique consensus.
 	//
 	// This configuration is intentionally not using keyed fields to force anyone
 	// adding flags to the config to also have to set these fields.
-	AllCliqueProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, &CliqueConfig{Period: 0, Epoch: 30000}}
+	AllCliqueProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, &CliqueConfig{Period: 0, Epoch: 30000}, nil}
 
-	TestChainConfig = &ChainConfig{big.NewInt(1), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil}
+	TestChainConfig = &ChainConfig{big.NewInt(1), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, new(EthashConfig), nil, nil}
 	TestRules       = TestChainConfig.Rules(new(big.Int))
 )
 
@@ -195,6 +195,7 @@ type ChainConfig struct {
 	// Various consensus engines
 	Ethash *EthashConfig `json:"ethash,omitempty"`
 	Clique *CliqueConfig `json:"clique,omitempty"`
+	Dexcon *DexconConfig `json:"dexcon,omitempty"`
 }
 
 // EthashConfig is the consensus engine configs for proof-of-work based sealing.
@@ -216,6 +217,16 @@ func (c *CliqueConfig) String() string {
 	return "clique"
 }
 
+// DexconConfig is the consensus engine configs for DEXON consensus.
+type DexconConfig struct {
+	GovernanceContractAddress string
+}
+
+// String implements the stringer interface, returning the consensus engine details.
+func (c *DexconConfig) String() string {
+	return "dexcon"
+}
+
 // String implements the fmt.Stringer interface.
 func (c *ChainConfig) String() string {
 	var engine interface{}
diff --git a/tests/testdata b/tests/testdata
-Subproject 6b85703b568f4456582a00665d8a3e5c3b20b48
+Subproject 3721fd6d83366103fe23dd29bbbf34bb80f9eb9