extern crate parity_hash; extern crate pwasm_ethereum; extern crate uint; use parity_hash::{H256, Address}; use pwasm_ethereum; use uint::U256; use pwasm_abi_derive::eth_abi; static TOTAL_SUPPLY_KEY: H256 = H256([2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]); static OWNER_KEY: H256 = H256([3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]); pub trait TokenContract { fn constructor(&mut self, _total_supply: U256); #[constant] fn totalSupply(&mut self) -> U256; #[constant] fn balanceOf(&mut self, _owner: Address) -> U256; fn transfer(&mut self, _to: Address, _amount: U256) -> bool; /// Event declaration #[event] fn Transfer(&mut self, indexed_from: Address, indexed_to: Address, _value: U256); } pub struct TokenContractInstance; // Reads balance by address fn read_balance_of(owner: &Address) -> U256 {	pwasm_ethereum::read(&balance_key(owner)).into() } // Generates a balance key for some address. // Used to map balances with their owners. fn balance_key(address: &Address) -> H256 { let mut key = H256::from(address);	key[0] = 1; // just a naiive "namespace";	key } impl TokenContract for TokenContractInstance { fn constructor(&mut self, total_supply: U256) { let sender = pwasm_ethereum::sender(); // Set up the total supply for the token	pwasm_ethereum::write(&TOTAL_SUPPLY_KEY, &total_supply.into()); // Give all tokens to the contract owner	pwasm_ethereum::write(&balance_key(&sender), &total_supply.into()); // Set the contract owner	pwasm_ethereum::write(&OWNER_KEY, &H256::from(sender).into()); } fn totalSupply(&mut self) -> U256 {	pwasm_ethereum::read(&TOTAL_SUPPLY_KEY).into() } fn balanceOf(&mut self, owner: Address) -> U256 { read_balance_of(&owner) } fn transfer(&mut self, to: Address, amount: U256) -> bool { let sender = pwasm_ethereum::sender(); let senderBalance = read_balance_of(&sender); let recipientBalance = read_balance_of(&to); if amount == 0.into() || senderBalance < amount { false } else { let new_sender_balance = senderBalance - amount; let new_recipient_balance = recipientBalance + amount;	pwasm_ethereum::write(&balance_key(&sender), &new_sender_balance.into());	pwasm_ethereum::write(&balance_key(&to), &new_recipient_balance.into()); self.Transfer(sender, to, amount); true } } } #[cfg(test)] #[macro_use] extern crate pwasm_test; #[cfg(test)] #[allow(non_snake_case)] mod tests { extern crate std; use super::*; use pwasm_test::{ext_reset, ext_get}; use parity_hash::Address; #[test] fn should_succeed_transfering_1000_from_owner_to_another_address() { let mut contract = TokenContractInstance{}; let owner_address = Address::from("0xea674fdde714fd979de3edf0f56aa9716b898ec8"); let sam_address = Address::from("0xdb6fd484cfa46eeeb73c71edee823e4812f9e2e1"); // Here we're creating an External context using ExternalBuilder and set the `sender` to the `owner_address` // so `pwasm_ethereum::sender()` in TokenContract::constructor() will return that `owner_address` ext_reset(|e| e.sender(owner_address.clone())); let total_supply = 10000.into(); contract.constructor(total_supply); assert_eq!(contract.balanceOf(owner_address), total_supply); assert_eq!(contract.transfer(sam_address, 1000.into()), true); assert_eq!(contract.balanceOf(owner_address), 9000.into()); assert_eq!(contract.balanceOf(sam_address), 1000.into()); // 1 log entry should be created assert_eq!(ext_get().logs().len(), 1); } }