package balancecontract import ( "github.com/nspcc-dev/neo-go/pkg/interop" "github.com/nspcc-dev/neo-go/pkg/interop/iterator" "github.com/nspcc-dev/neo-go/pkg/interop/native/management" "github.com/nspcc-dev/neo-go/pkg/interop/native/std" "github.com/nspcc-dev/neo-go/pkg/interop/runtime" "github.com/nspcc-dev/neo-go/pkg/interop/storage" "github.com/nspcc-dev/neofs-contract/common" ) type ( // Token holds all token info. Token struct { // Ticker symbol Symbol string // Amount of decimals Decimals int // Storage key for circulation value CirculationKey string } Account struct { // Active balance Balance int // Until valid for lock accounts Until int // Parent field used in lock accounts, used to return assets back if // account wasn't burnt. Parent []byte } ) const ( symbol = "NEOFS" decimals = 12 circulation = "MainnetGAS" version = 1 netmapContractKey = "netmapScriptHash" containerContractKey = "containerScriptHash" ) var ( lockTransferMsg = []byte("lock assets to withdraw") unlockTransferMsg = []byte("asset lock expired") token Token ) // CreateToken initializes the Token Interface for the Smart Contract to operate with. func CreateToken() Token { return Token{ Symbol: symbol, Decimals: decimals, CirculationKey: circulation, } } func init() { token = CreateToken() } func Init(owner, addrNetmap, addrContainer interop.Hash160) { ctx := storage.GetContext() if !common.HasUpdateAccess(ctx) { panic("only owner can reinitialize contract") } if len(addrNetmap) != 20 || len(addrContainer) != 20 { panic("init: incorrect length of contract script hash") } storage.Put(ctx, common.OwnerKey, owner) storage.Put(ctx, netmapContractKey, addrNetmap) storage.Put(ctx, containerContractKey, addrContainer) runtime.Log("balance contract initialized") } func Migrate(script []byte, manifest []byte) bool { ctx := storage.GetReadOnlyContext() if !common.HasUpdateAccess(ctx) { runtime.Log("only owner can update contract") return false } management.Update(script, manifest) runtime.Log("balance contract updated") return true } func Symbol() string { return token.Symbol } func Decimals() int { return token.Decimals } func TotalSupply() int { ctx := storage.GetReadOnlyContext() return token.getSupply(ctx) } func BalanceOf(account interop.Hash160) int { ctx := storage.GetReadOnlyContext() return token.balanceOf(ctx, account) } func Transfer(from, to interop.Hash160, amount int, data interface{}) bool { ctx := storage.GetContext() return token.transfer(ctx, from, to, amount, false, nil) } func TransferX(from, to interop.Hash160, amount int, details []byte) bool { ctx := storage.GetContext() multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey) if !runtime.CheckWitness(multiaddr) { panic("transferX: this method must be invoked from inner ring") } result := token.transfer(ctx, from, to, amount, true, details) if result { runtime.Log("transferX: success") } else { // consider panic there runtime.Log("transferX: fail") } return result } func Lock(txID []byte, from, to interop.Hash160, amount, until int) bool { ctx := storage.GetContext() multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey) if !runtime.CheckWitness(multiaddr) { panic("lock: this method must be invoked from inner ring") } lockAccount := Account{ Balance: 0, Until: until, Parent: from, } common.SetSerialized(ctx, to, lockAccount) result := token.transfer(ctx, from, to, amount, true, lockTransferMsg) if !result { // consider using `return false` to remove votes panic("lock: can't lock funds") } runtime.Log("lock: created lock account") runtime.Notify("Lock", txID, from, to, amount, until) return true } func NewEpoch(epochNum int) bool { ctx := storage.GetContext() multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey) if !runtime.CheckWitness(multiaddr) { panic("newEpoch: this method must be invoked from inner ring") } it := storage.Find(ctx, []byte{}, storage.KeysOnly) for iterator.Next(it) { addr := iterator.Value(it).(interop.Hash160) // it MUST BE `storage.KeysOnly` if len(addr) != 20 { continue } acc := getAccount(ctx, addr) if acc.Until == 0 { continue } if epochNum >= acc.Until { // return assets back to the parent token.transfer(ctx, addr, acc.Parent, acc.Balance, true, unlockTransferMsg) } } return true } func Mint(to interop.Hash160, amount int, details []byte) bool { ctx := storage.GetContext() multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey) if !runtime.CheckWitness(multiaddr) { panic("mint: this method must be invoked from inner ring") } ok := token.transfer(ctx, nil, to, amount, true, details) if !ok { panic("mint: can't transfer assets") } supply := token.getSupply(ctx) supply = supply + amount storage.Put(ctx, token.CirculationKey, supply) runtime.Log("mint: assets were minted") runtime.Notify("Mint", to, amount) return true } func Burn(from interop.Hash160, amount int, details []byte) bool { ctx := storage.GetContext() multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey) if !runtime.CheckWitness(multiaddr) { panic("burn: this method must be invoked from inner ring") } ok := token.transfer(ctx, from, nil, amount, true, details) if !ok { panic("burn: can't transfer assets") } supply := token.getSupply(ctx) if supply < amount { panic("panic, negative supply after burn") } supply = supply - amount storage.Put(ctx, token.CirculationKey, supply) runtime.Log("burn: assets were burned") runtime.Notify("Burn", from, amount) return true } func Version() int { return version } // getSupply gets the token totalSupply value from VM storage. func (t Token) getSupply(ctx storage.Context) int { supply := storage.Get(ctx, t.CirculationKey) if supply != nil { return supply.(int) } return 0 } // BalanceOf gets the token balance of a specific address. func (t Token) balanceOf(ctx storage.Context, holder interop.Hash160) int { acc := getAccount(ctx, holder) return acc.Balance } func (t Token) transfer(ctx storage.Context, from, to interop.Hash160, amount int, innerRing bool, details []byte) bool { amountFrom, ok := t.canTransfer(ctx, from, to, amount, innerRing) if !ok { return false } if len(from) == 20 { if amountFrom.Balance == amount { storage.Delete(ctx, from) } else { amountFrom.Balance = amountFrom.Balance - amount // neo-go#953 common.SetSerialized(ctx, from, amountFrom) } } if len(to) == 20 { amountTo := getAccount(ctx, to) amountTo.Balance = amountTo.Balance + amount // neo-go#953 common.SetSerialized(ctx, to, amountTo) } runtime.Notify("Transfer", from, to, amount) runtime.Notify("TransferX", from, to, amount, details) return true } // canTransfer returns the amount it can transfer. func (t Token) canTransfer(ctx storage.Context, from, to interop.Hash160, amount int, innerRing bool) (Account, bool) { var ( emptyAcc = Account{} ) if !innerRing { if len(to) != 20 || !isUsableAddress(from) { runtime.Log("transfer: bad script hashes") return emptyAcc, false } } else if len(from) == 0 { return emptyAcc, true } amountFrom := getAccount(ctx, from) if amountFrom.Balance < amount { runtime.Log("transfer: not enough assets") return emptyAcc, false } // return amountFrom value back to transfer, reduces extra Get return amountFrom, true } // isUsableAddress checks if the sender is either the correct NEO address or SC address. func isUsableAddress(addr interop.Hash160) bool { if len(addr) == 20 { if runtime.CheckWitness(addr) { return true } // Check if a smart contract is calling script hash callingScriptHash := runtime.GetCallingScriptHash() if common.BytesEqual(callingScriptHash, addr) { return true } } return false } func getAccount(ctx storage.Context, key interface{}) Account { data := storage.Get(ctx, key) if data != nil { return std.Deserialize(data.([]byte)).(Account) } return Account{} }