delay bomb for Classic (ECIP-1010) (#3179)

* delay bomb for classic (ECIP-1010)

* formatting fix after core review, rel [e6b5093]

ethcore/res/ethereum/classic.json

@@ -15,7 +15,9 @@
 				"eip155Transition": "0x7fffffffffffffff",
 				"eip160Transition": "0x7fffffffffffffff",
 				"eip161abcTransition": "0x7fffffffffffffff",
-				"eip161dTransition": "0x7fffffffffffffff"
+				"eip161dTransition": "0x7fffffffffffffff",
+				"ecip1010PauseTransition": "0x2dc6c0",
+				"ecip1010ContinueTransition": "0x4c4b40"
 			}
 		}
 	},

ethcore/src/ethereum/ethash.rs

@@ -70,6 +70,10 @@ pub struct EthashParams {
 	pub eip161abc_transition: u64,
 	/// Number of first block where EIP-161.d begins.
 	pub eip161d_transition: u64,
+	/// Number of first block where ECIP-1010 begins.
+	pub ecip1010_pause_transition: u64,
+	/// Number of first block where ECIP-1010 ends.
+	pub ecip1010_continue_transition: u64
 }
 
 impl From<ethjson::spec::EthashParams> for EthashParams {
@@ -94,6 +98,8 @@ impl From<ethjson::spec::EthashParams> for EthashParams {
 			eip160_transition: p.eip160_transition.map_or(0, Into::into),
 			eip161abc_transition: p.eip161abc_transition.map_or(0, Into::into),
 			eip161d_transition: p.eip161d_transition.map_or(0x7fffffffffffffff, Into::into),
+			ecip1010_pause_transition: p.ecip1010_pause_transition.map_or(0x7fffffffffffffff, Into::into),
+			ecip1010_continue_transition: p.ecip1010_continue_transition.map_or(0x7fffffffffffffff, Into::into),
 		}
 	}
 }
@@ -353,9 +359,20 @@ impl Ethash {
 		};
 		target = max(min_difficulty, target);
 		if header.number() < self.ethash_params.bomb_defuse_transition {
-			let period = ((parent.number() + 1) / EXP_DIFF_PERIOD) as usize;
+			if header.number() < self.ethash_params.ecip1010_pause_transition {
-			if period > 1 {
+				let period = ((parent.number() + 1) / EXP_DIFF_PERIOD) as usize;
-				target = max(min_difficulty, target + (U256::from(1) << (period - 2)));
+				if period > 1 {
+					target = max(min_difficulty, target + (U256::from(1) << (period - 2)));
+				}
+			}
+			else if header.number() < self.ethash_params.ecip1010_continue_transition {
+				let fixed_difficulty = ((self.ethash_params.ecip1010_pause_transition / EXP_DIFF_PERIOD) - 2) as usize;
+				target = max(min_difficulty, target + (U256::from(1) << fixed_difficulty));
+			}
+			else {
+				let period = ((parent.number() + 1) / EXP_DIFF_PERIOD) as usize;
+				let delay = ((self.ethash_params.ecip1010_continue_transition - self.ethash_params.ecip1010_pause_transition) / EXP_DIFF_PERIOD) as usize;
+				target = max(min_difficulty, target + (U256::from(1) << (period - delay - 2)));
 			}
 		}
 		target
@@ -414,8 +431,8 @@ mod tests {
 	use env_info::EnvInfo;
 	use error::{BlockError, Error};
 	use header::Header;
-	use super::super::new_morden;
+	use super::super::{new_morden, new_homestead_test};
-	use super::Ethash;
+	use super::{Ethash, EthashParams};
 	use rlp;
 
 	#[test]
@@ -637,5 +654,122 @@ mod tests {
 		assert_eq!(Ethash::difficulty_to_boundary(&U256::from(32)), H256::from_str("0800000000000000000000000000000000000000000000000000000000000000").unwrap());
 	}
 
-	// TODO: difficulty test
+	#[test]
+	fn difficulty_frontier() {
+		let spec = new_homestead_test();
+		let ethparams = get_default_ethash_params();
+		let ethash = Ethash::new(spec.params, ethparams, BTreeMap::new());
+
+		let mut parent_header = Header::default();
+		parent_header.set_number(1000000);
+		parent_header.set_difficulty(U256::from_str("b69de81a22b").unwrap());
+		parent_header.set_timestamp(1455404053);
+		let mut header = Header::default();
+		header.set_number(parent_header.number() + 1);
+		header.set_timestamp(1455404058);
+
+		let difficulty = ethash.calculate_difficulty(&header, &parent_header);
+		assert_eq!(U256::from_str("b6b4bbd735f").unwrap(), difficulty);
+	}
+
+	#[test]
+	fn difficulty_homestead() {
+		let spec = new_homestead_test();
+		let ethparams = get_default_ethash_params();
+		let ethash = Ethash::new(spec.params, ethparams, BTreeMap::new());
+
+		let mut parent_header = Header::default();
+		parent_header.set_number(1500000);
+		parent_header.set_difficulty(U256::from_str("1fd0fd70792b").unwrap());
+		parent_header.set_timestamp(1463003133);
+		let mut header = Header::default();
+		header.set_number(parent_header.number() + 1);
+		header.set_timestamp(1463003177);
+
+		let difficulty = ethash.calculate_difficulty(&header, &parent_header);
+		assert_eq!(U256::from_str("1fc50f118efe").unwrap(), difficulty);
+	}
+
+	#[test]
+	fn difficulty_classic_bomb_delay() {
+		let spec = new_homestead_test();
+		let ethparams = EthashParams {
+			ecip1010_pause_transition: 3000000,
+			..get_default_ethash_params()
+		};
+		let ethash = Ethash::new(spec.params, ethparams, BTreeMap::new());
+
+		let mut parent_header = Header::default();
+		parent_header.set_number(3500000);
+		parent_header.set_difficulty(U256::from_str("6F62EAF8D3C").unwrap());
+		parent_header.set_timestamp(1452838500);
+		let mut header = Header::default();
+		header.set_number(parent_header.number() + 1);
+
+		header.set_timestamp(parent_header.timestamp() + 20);
+		assert_eq!(
+			U256::from_str("6F55FE9B74B").unwrap(),
+			ethash.calculate_difficulty(&header, &parent_header)
+		);
+		header.set_timestamp(parent_header.timestamp() + 5);
+		assert_eq!(
+			U256::from_str("6F71D75632D").unwrap(),
+			ethash.calculate_difficulty(&header, &parent_header)
+		);
+		header.set_timestamp(parent_header.timestamp() + 80);
+		assert_eq!(
+			U256::from_str("6F02746B3A5").unwrap(),
+			ethash.calculate_difficulty(&header, &parent_header)
+		);
+	}
+
+	#[test]
+	fn test_difficulty_bomb_continue() {
+		let spec = new_homestead_test();
+		let ethparams = EthashParams {
+			ecip1010_pause_transition: 3000000,
+			ecip1010_continue_transition: 5000000,
+			..get_default_ethash_params()
+		};
+		let ethash = Ethash::new(spec.params, ethparams, BTreeMap::new());
+
+		let mut parent_header = Header::default();
+		parent_header.set_number(5000102);
+		parent_header.set_difficulty(U256::from_str("14944397EE8B").unwrap());
+		parent_header.set_timestamp(1513175023);
+		let mut header = Header::default();
+		header.set_number(parent_header.number() + 1);
+		header.set_timestamp(parent_header.timestamp() + 6);
+		assert_eq!(
+			U256::from_str("1496E6206188").unwrap(),
+			ethash.calculate_difficulty(&header, &parent_header)
+		);
+		parent_header.set_number(5100123);
+		parent_header.set_difficulty(U256::from_str("14D24B39C7CF").unwrap());
+		parent_header.set_timestamp(1514609324);
+		header.set_number(parent_header.number() + 1);
+		header.set_timestamp(parent_header.timestamp() + 41);
+		assert_eq!(
+			U256::from_str("14CA9C5D9227").unwrap(),
+			ethash.calculate_difficulty(&header, &parent_header)
+		);
+		parent_header.set_number(6150001);
+		parent_header.set_difficulty(U256::from_str("305367B57227").unwrap());
+		parent_header.set_timestamp(1529664575);
+		header.set_number(parent_header.number() + 1);
+		header.set_timestamp(parent_header.timestamp() + 105);
+		assert_eq!(
+			U256::from_str("309D09E0C609").unwrap(),
+			ethash.calculate_difficulty(&header, &parent_header)
+		);
+		parent_header.set_number(8000000);
+		parent_header.set_difficulty(U256::from_str("1180B36D4CE5B6A").unwrap());
+		parent_header.set_timestamp(1535431724);
+		header.set_number(parent_header.number() + 1);
+		header.set_timestamp(parent_header.timestamp() + 420);
+		assert_eq!(
+			U256::from_str("5126FFD5BCBB9E7").unwrap(),
+			ethash.calculate_difficulty(&header, &parent_header)
+		);
+	}
 }

ethcore/src/tests/helpers.rs

@@ -28,6 +28,7 @@ use evm::Schedule;
 use engines::Engine;
 use env_info::EnvInfo;
 use ethereum;
+use ethereum::ethash::EthashParams;
 use devtools::*;
 use miner::Miner;
 use header::Header;
@@ -421,3 +422,29 @@ pub fn get_bad_state_dummy_block() -> Bytes {
 
 	create_test_block(&block_header)
 }
+
+pub fn get_default_ethash_params() -> EthashParams{
+	EthashParams {
+		gas_limit_bound_divisor: U256::from(1024),
+		minimum_difficulty: U256::from(131072),
+		difficulty_bound_divisor: U256::from(2048),
+		difficulty_increment_divisor: 10,
+		duration_limit: 13,
+		block_reward: U256::from(0),
+		registrar: "0000000000000000000000000000000000000001".into(),
+		homestead_transition: 1150000,
+		dao_hardfork_transition: 0x7fffffffffffffff,
+		dao_hardfork_beneficiary: "0000000000000000000000000000000000000001".into(),
+		dao_hardfork_accounts: vec![],
+		difficulty_hardfork_transition: 0x7fffffffffffffff,
+		difficulty_hardfork_bound_divisor: U256::from(0),
+		bomb_defuse_transition: 0x7fffffffffffffff,
+		eip150_transition: 0x7fffffffffffffff,
+		eip155_transition: 0x7fffffffffffffff,
+		eip160_transition: 0x7fffffffffffffff,
+		eip161abc_transition: 0x7fffffffffffffff,
+		eip161d_transition: 0x7fffffffffffffff,
+		ecip1010_pause_transition: 0x7fffffffffffffff,
+		ecip1010_continue_transition: 0x7fffffffffffffff
+	}
+}

json/src/spec/ethash.rs

@@ -85,6 +85,13 @@ pub struct EthashParams {
 	/// See main EthashParams docs.
 	#[serde(rename="eip161dTransition")]
 	pub eip161d_transition: Option<Uint>,
+
+	/// See main EthashParams docs.
+	#[serde(rename="ecip1010PauseTransition")]
+	pub ecip1010_pause_transition: Option<Uint>,
+	/// See main EthashParams docs.
+	#[serde(rename="ecip1010ContinueTransition")]
+	pub ecip1010_continue_transition: Option<Uint>,
 }
 
 /// Ethash engine deserialization.