Store gas_price in the storage

substrate/runtime/contract/src/exec.rs

@@ -20,7 +20,7 @@ use gas::GasMeter;
 use vm;
 
 use rstd::prelude::*;
-use runtime_primitives::traits::{As, Zero};
+use runtime_primitives::traits::Zero;
 use runtime_support::StorageMap;
 use staking;
 use system;
@@ -36,7 +36,6 @@ pub struct ExecutionContext<'a, 'b: 'a, T: Trait + 'b> {
 	// typically should be dest
 	pub self_account: T::AccountId,
 	pub account_db: &'a mut OverlayAccountDb<'b, T>,
-	pub gas_price: T::Balance,
 	pub depth: usize,
 }
 
@@ -46,7 +45,7 @@ impl<'a, 'b: 'a, T: Trait> ExecutionContext<'a, 'b, T> {
 		&mut self,
 		dest: T::AccountId,
 		value: T::Balance,
-		gas_meter: &mut GasMeter<T::Gas>,
+		gas_meter: &mut GasMeter<T>,
 		_data: Vec<u8>,
 	) -> Result<vm::ExecutionResult, &'static str> {
 		let dest_code = <CodeOf<T>>::get(&dest);
@@ -64,7 +63,6 @@ impl<'a, 'b: 'a, T: Trait> ExecutionContext<'a, 'b, T> {
 			if value > T::Balance::zero() {
 				transfer(
 					gas_meter,
-					self.gas_price,
 					false,
 					&self.self_account,
 					&dest,
@@ -78,7 +76,6 @@ impl<'a, 'b: 'a, T: Trait> ExecutionContext<'a, 'b, T> {
 					account_db: &mut overlay,
 					_caller: self.self_account.clone(),
 					self_account: dest.clone(),
-					gas_price: self.gas_price,
 					depth: self.depth + 1,
 				};
 
@@ -102,7 +99,7 @@ impl<'a, 'b: 'a, T: Trait> ExecutionContext<'a, 'b, T> {
 	pub fn create(
 		&mut self,
 		endownment: T::Balance,
-		gas_meter: &mut GasMeter<T::Gas>,
+		gas_meter: &mut GasMeter<T>,
 		ctor: &[u8],
 		_data: &[u8],
 	) -> Result<CreateReceipt<T>, &'static str> {
@@ -122,7 +119,6 @@ impl<'a, 'b: 'a, T: Trait> ExecutionContext<'a, 'b, T> {
 			if endownment > T::Balance::zero() {
 				transfer(
 					gas_meter,
-					self.gas_price,
 					true,
 					&self.self_account,
 					&dest,
@@ -136,7 +132,6 @@ impl<'a, 'b: 'a, T: Trait> ExecutionContext<'a, 'b, T> {
 					account_db: &mut overlay,
 					_caller: self.self_account.clone(),
 					self_account: dest.clone(),
-					gas_price: self.gas_price,
 					depth: self.depth + 1,
 				};
 				vm::execute(ctor, &mut nested, gas_meter)
@@ -158,8 +153,7 @@ impl<'a, 'b: 'a, T: Trait> ExecutionContext<'a, 'b, T> {
 }
 
 fn transfer<T: Trait>(
-	gas_meter: &mut GasMeter<T::Gas>,
-	gas_price: T::Balance,
+	gas_meter: &mut GasMeter<T>,
 	contract_create: bool,
 	transactor: &T::AccountId,
 	dest: &T::AccountId,
@@ -178,10 +172,7 @@ fn transfer<T: Trait>(
 		}
 	};
 
-	// Convert fee into gas units and charge it from gas meter.
-	let gas_fee: T::Balance = fee / gas_price;
-	let gas_fee: T::Gas = <T::Gas as As<T::Balance>>::sa(gas_fee);
-	if gas_meter.charge(gas_fee).is_out_of_gas() {
+	if gas_meter.charge_by_balance(fee).is_out_of_gas() {
 		return Err("not enough gas to pay transfer fee");
 	}
 
@@ -223,7 +214,7 @@ impl<'a, 'b: 'a, T: Trait + 'b> vm::Ext<T> for ExecutionContext<'a, 'b, T> {
 		&mut self,
 		code: &[u8],
 		endownment: T::Balance,
-		gas_meter: &mut GasMeter<T::Gas>,
+		gas_meter: &mut GasMeter<T>,
 		data: Vec<u8>,
 	) -> Result<vm::CreateReceipt<T::AccountId, T::Gas>, ()> {
 		let receipt = self
@@ -239,7 +230,7 @@ impl<'a, 'b: 'a, T: Trait + 'b> vm::Ext<T> for ExecutionContext<'a, 'b, T> {
 		&mut self,
 		to: &T::AccountId,
 		value: T::Balance,
-		gas_meter: &mut GasMeter<T::Gas>,
+		gas_meter: &mut GasMeter<T>,
 		data: Vec<u8>,
 	) -> Result<vm::ExecutionResult, ()> {
 		self.call(to.clone(), value, gas_meter, data)

substrate/runtime/contract/src/gas.rs

@@ -14,9 +14,9 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate. If not, see <http://www.gnu.org/licenses/>.
 
-use runtime_primitives::traits::{As, CheckedMul, SimpleArithmetic};
+use {Trait, Module};
+use runtime_primitives::traits::{As, CheckedMul, CheckedSub, Zero};
 use staking;
-use Trait;
 
 #[must_use]
 #[derive(Debug, PartialEq, Eq)]
@@ -34,22 +34,24 @@ impl GasMeterResult {
 	}
 }
 
-pub struct GasMeter<U> {
-	gas_left: U,
+pub struct GasMeter<T: Trait> {
+	gas_left: T::Gas,
+	gas_price: T::Balance,
 }
-impl<U: SimpleArithmetic + Copy> GasMeter<U> {
+impl<T: Trait> GasMeter<T> {
 	#[cfg(test)]
-	pub fn with_limit(gas_limit: U) -> GasMeter<U> {
+	pub fn with_limit(gas_limit: T::Gas, gas_price: T::Balance) -> GasMeter<T> {
 		GasMeter {
 			gas_left: gas_limit,
+			gas_price,
 		}
 	}
 
 	/// Account for used gas.
 	///
 	/// Returns `OutOfGas` if there is not enough gas or addition of the specified
 	/// amount of gas has lead to overflow. On success returns `Proceed`.
-	pub fn charge(&mut self, amount: U) -> GasMeterResult {
+	pub fn charge(&mut self, amount: T::Gas) -> GasMeterResult {
 		match self.gas_left.checked_sub(&amount) {
 			None => GasMeterResult::OutOfGas,
 			Some(val) if val.is_zero() => GasMeterResult::OutOfGas,
@@ -60,9 +62,15 @@ impl<U: SimpleArithmetic + Copy> GasMeter<U> {
 		}
 	}
 
-	pub fn with_nested<R, F: FnOnce(Option<&mut GasMeter<U>>) -> R>(
+	pub fn charge_by_balance(&mut self, amount: T::Balance) -> GasMeterResult {
+		let amount_in_gas: T::Balance = amount / self.gas_price;
+		let amount_in_gas: T::Gas = <T::Gas as As<T::Balance>>::sa(amount_in_gas);
+		self.charge(amount_in_gas)
+	}
+
+	pub fn with_nested<R, F: FnOnce(Option<&mut GasMeter<T>>) -> R>(
 		&mut self,
-		amount: U,
+		amount: T::Gas,
 		f: F,
 	) -> R {
 		// NOTE that it is ok to allocate all available gas since it still ensured
@@ -71,7 +79,10 @@ impl<U: SimpleArithmetic + Copy> GasMeter<U> {
 			f(None)
 		} else {
 			self.gas_left = self.gas_left - amount;
-			let mut nested = GasMeter { gas_left: amount };
+			let mut nested = GasMeter {
+				gas_left: amount,
+				gas_price: self.gas_price,
+			};
 
 			let r = f(Some(&mut nested));
 
@@ -82,16 +93,16 @@ impl<U: SimpleArithmetic + Copy> GasMeter<U> {
 	}
 
 	/// Returns how much gas left from the initial budget.
-	pub fn gas_left(&self) -> U {
+	pub fn gas_left(&self) -> T::Gas {
 		self.gas_left
 	}
 }
 
 pub fn buy_gas<T: Trait>(
 	transactor: &T::AccountId,
 	gas_limit: T::Gas,
-	gas_price: T::Balance,
-) -> Result<GasMeter<T::Gas>, &'static str> {
+) -> Result<GasMeter<T>, &'static str> {
+	let gas_price = <Module<T>>::gas_price();
 	let b = <staking::Module<T>>::free_balance(transactor);
 	let cost = <T::Gas as As<T::Balance>>::as_(gas_limit.clone())
 		.checked_mul(&gas_price)
@@ -102,15 +113,12 @@ pub fn buy_gas<T: Trait>(
 	<staking::Module<T>>::set_free_balance(transactor, b - cost);
 	Ok(GasMeter {
 		gas_left: gas_limit,
+		gas_price,
 	})
 }
 
-pub fn refund_unused_gas<T: Trait>(
-	transactor: &T::AccountId,
-	gas_meter: GasMeter<T::Gas>,
-	gas_price: T::Balance,
-) {
+pub fn refund_unused_gas<T: Trait>(transactor: &T::AccountId, gas_meter: GasMeter<T>) {
 	let b = <staking::Module<T>>::free_balance(transactor);
-	let refund = <T::Gas as As<T::Balance>>::as_(gas_meter.gas_left) * gas_price;
+	let refund = <T::Gas as As<T::Balance>>::as_(gas_meter.gas_left) * gas_meter.gas_price;
 	<staking::Module<T>>::set_free_balance(transactor, b + refund);
 }

substrate/runtime/contract/src/genesis_config.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate. If not, see <http://www.gnu.org/licenses/>.
 
-use {Trait, ContractFee, CallBaseFee, CreateBaseFee};
+use {Trait, ContractFee, CallBaseFee, CreateBaseFee, GasPrice};
 
 use runtime_primitives;
 use runtime_io::{self, twox_128};
@@ -28,14 +28,16 @@ pub struct GenesisConfig<T: Trait> {
 	pub contract_fee: T::Balance,
 	pub call_base_fee: T::Gas,
 	pub create_base_fee: T::Gas,
+	pub gas_price: T::Balance,
 }
 
 impl<T: Trait> runtime_primitives::BuildStorage for GenesisConfig<T> {
 	fn build_storage(self) -> Result<runtime_io::TestExternalities, String> {
 		let r: runtime_io::TestExternalities = map![
 			twox_128(<ContractFee<T>>::key()).to_vec() => self.contract_fee.encode(),
 			twox_128(<CallBaseFee<T>>::key()).to_vec() => self.call_base_fee.encode(),
-			twox_128(<CreateBaseFee<T>>::key()).to_vec() => self.create_base_fee.encode()
+			twox_128(<CreateBaseFee<T>>::key()).to_vec() => self.create_base_fee.encode(),
+			twox_128(<GasPrice<T>>::key()).to_vec() => self.gas_price.encode()
 		];
 		Ok(r)
 	}