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| #![cfg_attr(not(feature = "std"), no_std)]
use ink_lang as ink;
#[ink::contract]
mod erc20 {
use ink_lang::codegen::Env;
use ink_lang::codegen::EmitEvent;
use ink_storage::{
Mapping,
traits::SpreadAllocate,
};
#[ink(storage)]
#[derive(SpreadAllocate)]
pub struct Erc20 {
total_supply: Balance,
balances: Mapping<AccountId,Balance>,
allowances: Mapping<(AccountId,AccountId),Balance>,
owner: AccountId,
decimals: u8,
}
#[ink(event)]
pub struct Transfer {
#[ink(topic)]
from: Option<AccountId>,
#[ink(topic)]
to: Option<AccountId>,
value: Balance,
}
#[ink(event)]
pub struct Approval {
#[ink(topic)]
owner: AccountId,
#[ink(topic)]
spender: AccountId,
value: Balance,
}
#[derive(Debug, PartialEq, Eq, scale::Encode, scale::Decode)]
#[cfg_attr(feature = "std", derive(scale_info::TypeInfo))]
pub enum Error {
InsufficientBalance,
InsufficientAllowance,
NotOwner,
OnlyOwner,
}
pub type Result<T> = core::result::Result<T, Error>;
#[ink_lang::trait_definition]
pub trait BaseErc20 {
#[ink(message)]
fn total_supply(&self) -> Balance;
#[ink(message)]
fn balance_of(&self,owner:AccountId) -> Balance;
#[ink(message)]
fn mint(&mut self, owner: AccountId, value: Balance) -> Result<()> ;
#[ink(message)]
fn burn(&mut self, owner: AccountId, value: Balance) -> Result<()> ;
#[ink(message)]
fn approve(&mut self, spender: AccountId, value: Balance) -> Result<()> ;
#[ink(message)]
fn allowance(&self, owner: AccountId,spender: AccountId) -> Balance;
#[ink(message)]
fn owner(&self) -> AccountId;
#[ink(message)]
fn decimals(&self) -> u8;
#[ink(message)]
fn transfer(&mut self, to: AccountId, value: Balance) -> Result<()>;
#[ink(message)]
fn transfer_from(&mut self, from: AccountId,to: AccountId, value: Balance) -> Result<()>;
}
impl Erc20 {
#[ink(constructor)]
pub fn new(initial_supply: Balance, decimals: u8) -> Self {
ink_lang::codegen::initialize_contract(|contract| {
Self::new_init(contract, initial_supply,decimals)
})
}
fn new_init(&mut self, initial_supply: Balance,decimals: u8) {
let caller = Self::env().caller();
self.balances.insert(&caller, &initial_supply);
self.owner = caller;
self.decimals = decimals;
self.total_supply = initial_supply;
}
}
impl BaseErc20 for Erc20 {
#[ink(message)]
fn mint(&mut self, owner: AccountId, value: Balance) -> Result<()> {
if self.owner != self.env().caller(){
return Err(Error::OnlyOwner)
}
self.add_total_supply(value);
let owner_balance = self.balances.get(&owner).unwrap_or_default().clone();
self.balances.insert(&owner, &(owner_balance + value));
Ok(())
}
#[ink(message)]
fn burn(&mut self, owner: AccountId, value: Balance) -> Result<()>{
if owner != self.env().caller(){
return Err(Error::NotOwner)
}
let owner_balance = self.balances.get(&owner).unwrap_or_default().clone();
if owner_balance < value {
return Err(Error::InsufficientBalance)
}
self.sub_total_supply(value);
self.balances.insert(&owner,&(owner_balance - value));
Ok(())
}
#[ink(message)]
fn total_supply(&self) -> Balance{
self.total_supply
}
#[ink(message)]
fn balance_of(&self,owner:AccountId) -> Balance{
self.balances.get(owner).unwrap_or_default()
}
#[ink(message)]
fn approve(&mut self, spender: AccountId, value: Balance) -> Result<()> {
let owner = self.env().caller();
self.allowances.insert((&owner, &spender), &value);
self.env().emit_event(Approval {
owner,
spender,
value,
});
Ok(())
}
#[ink(message)]
fn allowance(&self,owner: AccountId,spender: AccountId) -> Balance{
self.allowance_impl(&owner, &spender)
}
#[ink(message)]
fn owner(&self) -> AccountId{
self.owner
}
#[ink(message)]
fn transfer(&mut self, to: AccountId, value: Balance) -> Result<()>{
let owner = self.env().caller();
self.transfer_from_to(&owner,&to,value)
}
#[ink(message)]
fn transfer_from(
&mut self,
from: AccountId,
to: AccountId,
value: Balance,
) -> Result<()> {
let caller = self.env().caller();
let allowance = self.allowance_impl(&from, &caller);
if allowance < value {
return Err(Error::InsufficientAllowance)
}
self.transfer_from_to(&from, &to, value)?;
self.allowances
.insert((&from, &caller), &(allowance - value));
Ok(())
}
#[ink(message)]
fn decimals(&self) -> u8{
self.decimals
}
}
impl Erc20 {
fn add_total_supply(&mut self, value: Balance) {
let total_supply = &mut self.total_supply;
let cur = total_supply;
self.total_supply = *cur + value;
}
fn sub_total_supply(&mut self, value: Balance){
let total_supply = &mut self.total_supply;
let cur = total_supply;
self.total_supply = *cur - value;
}
fn transfer_from_to(&mut self,from: &AccountId,to: &AccountId, value: Balance) -> Result<()>{
let from_balance = self.balances.get(from).unwrap_or_default().clone();
if from_balance < value{
return Err(Error::InsufficientBalance)
}
self.balances.insert(from, &(from_balance - value));
let to_balance = self.balances.get(to).unwrap_or_default().clone();
self.balances.insert(to, &(to_balance + value));
self.env().emit_event(Transfer {
from: Some(*from),
to: Some(*to),
value,
});
Ok(())
}
fn allowance_impl(&self, owner: &AccountId, spender: &AccountId) ->Balance{
self.allowances.get((owner, spender)).unwrap_or_default()
}
}
}
|