Implement EIP-1052 (EXTCODEHASH) and fix several issues in state account cache (#9234)

* Implement EIP-1052 and fix several issues related to account cache

* Fix jsontests

* Merge two matches together

* Avoid making unnecessary Arc<Vec>

* Address grumbles

ethcore/vm/src/ext.rs

@@ -106,10 +106,13 @@ pub trait Ext {
 	) -> MessageCallResult;
 
 	/// Returns code at given address
-	fn extcode(&self, address: &Address) -> Result<Arc<Bytes>>;
+	fn extcode(&self, address: &Address) -> Result<Option<Arc<Bytes>>>;
+
+	/// Returns code hash at given address
+	fn extcodehash(&self, address: &Address) -> Result<Option<H256>>;
 
 	/// Returns code size at given address
-	fn extcodesize(&self, address: &Address) -> Result<usize>;
+	fn extcodesize(&self, address: &Address) -> Result<Option<usize>>;
 
 	/// Creates log entry with given topics and data
 	fn log(&mut self, topics: Vec<H256>, data: &[u8]) -> Result<()>;

ethcore/vm/src/schedule.rs

@@ -26,6 +26,8 @@ pub struct Schedule {
 	pub have_create2: bool,
 	/// Does it have a REVERT instruction
 	pub have_revert: bool,
+	/// Does it have a EXTCODEHASH instruction
+	pub have_extcodehash: bool,
 	/// VM stack limit
 	pub stack_limit: usize,
 	/// Max number of nested calls/creates
@@ -92,6 +94,8 @@ pub struct Schedule {
 	pub extcodecopy_base_gas: usize,
 	/// Price of BALANCE
 	pub balance_gas: usize,
+	/// Price of EXTCODEHASH
+	pub extcodehash_gas: usize,
 	/// Price of SUICIDE
 	pub suicide_gas: usize,
 	/// Amount of additional gas to pay when SUICIDE credits a non-existant account
@@ -197,6 +201,7 @@ impl Schedule {
 			have_revert: false,
 			have_return_data: false,
 			have_bitwise_shifting: false,
+			have_extcodehash: false,
 			stack_limit: 1024,
 			max_depth: 1024,
 			tier_step_gas: [0, 2, 3, 5, 8, 10, 20, 0],
@@ -229,6 +234,7 @@ impl Schedule {
 			copy_gas: 3,
 			extcodesize_gas: 700,
 			extcodecopy_base_gas: 700,
+			extcodehash_gas: 400,
 			balance_gas: 400,
 			suicide_gas: 5000,
 			suicide_to_new_account_cost: 25000,
@@ -268,6 +274,7 @@ impl Schedule {
 			have_revert: false,
 			have_return_data: false,
 			have_bitwise_shifting: false,
+			have_extcodehash: false,
 			stack_limit: 1024,
 			max_depth: 1024,
 			tier_step_gas: [0, 2, 3, 5, 8, 10, 20, 0],
@@ -300,6 +307,7 @@ impl Schedule {
 			copy_gas: 3,
 			extcodesize_gas: 20,
 			extcodecopy_base_gas: 20,
+			extcodehash_gas: 400,
 			balance_gas: 20,
 			suicide_gas: 0,
 			suicide_to_new_account_cost: 0,

ethcore/vm/src/tests.rs

@@ -24,6 +24,7 @@ use {
 	ReturnData, Ext, ContractCreateResult, MessageCallResult,
 	CreateContractAddress, Result, GasLeft,
 };
+use hash::keccak;
 
 pub struct FakeLogEntry {
 	pub topics: Vec<H256>,
@@ -168,12 +169,16 @@ impl Ext for FakeExt {
 		MessageCallResult::Success(*gas, ReturnData::empty())
 	}
 
-	fn extcode(&self, address: &Address) -> Result<Arc<Bytes>> {
-		Ok(self.codes.get(address).unwrap_or(&Arc::new(Bytes::new())).clone())
+	fn extcode(&self, address: &Address) -> Result<Option<Arc<Bytes>>> {
+		Ok(self.codes.get(address).cloned())
 	}
 
-	fn extcodesize(&self, address: &Address) -> Result<usize> {
-		Ok(self.codes.get(address).map_or(0, |c| c.len()))
+	fn extcodesize(&self, address: &Address) -> Result<Option<usize>> {
+		Ok(self.codes.get(address).map(|c| c.len()))
+	}
+
+	fn extcodehash(&self, address: &Address) -> Result<Option<H256>> {
+		Ok(self.codes.get(address).map(|c| keccak(c.as_ref())))
 	}
 
 	fn log(&mut self, topics: Vec<H256>, data: &[u8]) -> Result<()> {