Ethereum classic (#1706)

* Add Ethereum Classic support

(Rename homestead-dogmatic -> classic)

* Additional change needed.

* More needed changes.

* Separate database path for known forks.

* Address minor grumble.

ethcore/res/ethereum/classic.json

@@ -1,5 +1,6 @@
 {
-	"name": "Frontier/Homestead",
+	"name": "Ethereum Classic",
+	"forkName": "classic",
 	"engine": {
 		"Ethash": {
 			"params": {

ethcore/src/client/client.rs

@@ -149,9 +149,9 @@ const HISTORY: u64 = 1200;
 const CLIENT_DB_VER_STR: &'static str = "5.3";
 
 /// Get the path for the databases given the root path and information on the databases.
-pub fn get_db_path(path: &Path, pruning: journaldb::Algorithm, genesis_hash: H256) -> PathBuf {
+pub fn get_db_path(path: &Path, pruning: journaldb::Algorithm, genesis_hash: H256, fork_name: Option<&String>) -> PathBuf {
 	let mut dir = path.to_path_buf();
-	dir.push(H64::from(genesis_hash).hex());
+	dir.push(format!("{:?}{}", H64::from(genesis_hash), fork_name.map(|f| format!("-{}", f)).unwrap_or_default()));
 	//TODO: sec/fat: pruned/full versioning
 	// version here is a bit useless now, since it's controlled only be the pruning algo.
 	dir.push(format!("v{}-sec-{}", CLIENT_DB_VER_STR, pruning));
@@ -174,7 +174,7 @@ impl Client {
 		miner: Arc<Miner>,
 		message_channel: IoChannel<ClientIoMessage>,
 	) -> Result<Arc<Client>, ClientError> {
-		let path = get_db_path(path, config.pruning, spec.genesis_header().hash());
+		let path = get_db_path(path, config.pruning, spec.genesis_header().hash(), spec.fork_name.as_ref());
 		let gb = spec.genesis_block();
 		let chain = Arc::new(BlockChain::new(config.blockchain, &gb, &path));
 		let tracedb = Arc::new(try!(TraceDB::new(config.tracing, &path, chain.clone())));

ethcore/src/ethereum/mod.rs

@@ -33,14 +33,10 @@ use super::spec::*;
 pub fn new_olympic() -> Spec { Spec::load(include_bytes!("../../res/ethereum/olympic.json")) }
 
 /// Create a new Frontier mainnet chain spec.
-pub fn new_frontier() -> Spec {
+pub fn new_frontier() -> Spec { Spec::load(include_bytes!("../../res/ethereum/frontier.json")) }
-	Spec::load(include_bytes!("../../res/ethereum/frontier.json"))
-}
 
 /// Create a new Frontier mainnet chain spec without the DAO hardfork.
-pub fn new_frontier_dogmatic() -> Spec {
+pub fn new_classic() -> Spec { Spec::load(include_bytes!("../../res/ethereum/classic.json")) }
-	Spec::load(include_bytes!("../../res/ethereum/frontier-dogmatic.json"))
-}
 
 /// Create a new Frontier chain spec as though it never changes to Homestead.
 pub fn new_frontier_test() -> Spec { Spec::load(include_bytes!("../../res/ethereum/frontier_test.json")) }

ethcore/src/service.rs

@@ -62,6 +62,9 @@ impl ClientService {
 		panic_handler.forward_from(&io_service);
 
 		info!("Configured for {} using {} engine", Colour::White.bold().paint(spec.name.clone()), Colour::Yellow.bold().paint(spec.engine.name()));
+		if spec.fork_name.is_some() {
+			warn!("Your chain is an alternative fork. {}", Colour::Red.bold().paint("TRANSACTIONS MAY BE REPLAYED ON THE MAINNET!"));
+		}
 		let client = try!(Client::new(config, spec, db_path, miner, io_service.channel()));
 		panic_handler.forward_from(client.deref());
 		let client_io = Arc::new(ClientIoHandler {

ethcore/src/spec/spec.rs

@@ -58,6 +58,8 @@ pub struct Spec {
 	pub name: String,
 	/// What engine are we using for this?
 	pub engine: Box<Engine>,
+	/// The fork identifier for this chain. Only needed to distinguish two chains sharing the same genesis.
+	pub fork_name: Option<String>,
 
 	/// Known nodes on the network in enode format.
 	pub nodes: Vec<String>,
@@ -105,6 +107,7 @@ impl From<ethjson::spec::Spec> for Spec {
 			name: s.name.into(),
 			params: params.clone(),
 			engine: Spec::engine(s.engine, params, builtins),
+			fork_name: s.fork_name.map(Into::into),
 			nodes: s.nodes.unwrap_or_else(Vec::new),
 			parent_hash: g.parent_hash,
 			transactions_root: g.transactions_root,
@@ -118,7 +121,7 @@ impl From<ethjson::spec::Spec> for Spec {
 			seal_fields: seal.fields,
 			seal_rlp: seal.rlp,
 			state_root_memo: RwLock::new(g.state_root),
-			genesis_state: From::from(s.accounts)
+			genesis_state: From::from(s.accounts),
 		}
 	}
 }

json/src/spec/spec.rs

@@ -26,6 +26,9 @@ use spec::{Params, Genesis, Engine, State};
 pub struct Spec {
 	/// Spec name.
 	pub name: String,
+	/// Special fork name.
+	#[serde(rename="forkName")]
+	pub fork_name: Option<String>,
 	/// Engine.
 	pub engine: Engine,
 	/// Spec params.

parity/configuration.rs

@@ -201,7 +201,7 @@ impl Configuration {
 	pub fn spec(&self) -> Spec {
 		match self.chain().as_str() {
 			"frontier" | "homestead" | "mainnet" => ethereum::new_frontier(),
-			"homestead-dogmatic" => ethereum::new_frontier_dogmatic(),
+			"frontier-dogmatic" | "homestead-dogmatic" | "classic" => ethereum::new_classic(),
 			"morden" | "testnet" => ethereum::new_morden(),
 			"olympic" => ethereum::new_olympic(),
 			f => Spec::load(contents(f).unwrap_or_else(|_| {
@@ -288,7 +288,7 @@ impl Configuration {
 		let mut latest_era = None;
 		let jdb_types = [journaldb::Algorithm::Archive, journaldb::Algorithm::EarlyMerge, journaldb::Algorithm::OverlayRecent, journaldb::Algorithm::RefCounted];
 		for i in jdb_types.into_iter() {
-			let db = journaldb::new(&append_path(&get_db_path(Path::new(&self.path()), *i, spec.genesis_header().hash()), "state"), *i, kvdb::DatabaseConfig::default());
+			let db = journaldb::new(&append_path(&get_db_path(Path::new(&self.path()), *i, spec.genesis_header().hash(), spec.fork_name.as_ref()), "state"), *i, kvdb::DatabaseConfig::default());
 			trace!(target: "parity", "Looking for best DB: {} at {:?}", i, db.latest_era());
 			match (latest_era, db.latest_era()) {
 				(Some(best), Some(this)) if best >= this => {}

parity/main.rs

@@ -188,7 +188,7 @@ fn execute_upgrades(conf: &Configuration, spec: &Spec, client_config: &ClientCon
 		_ => {},
 	}
 
-	let db_path = get_db_path(Path::new(&conf.path()), client_config.pruning, spec.genesis_header().hash());
+	let db_path = get_db_path(Path::new(&conf.path()), client_config.pruning, spec.genesis_header().hash(), spec.fork_name.as_ref());
 	let result = migrate(&db_path, client_config.pruning);
 	if let Err(err) = result {
 		die_with_message(&format!("{} DB path: {}", err, db_path.to_string_lossy()));