frostfs-contract/balance/balance_contract.go

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package balancecontract
import (
"github.com/nspcc-dev/neo-go/pkg/interop"
"github.com/nspcc-dev/neo-go/pkg/interop/binary"
"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/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")
ctx storage.Context
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() {
ctx = storage.GetContext()
token = CreateToken()
}
func Init(owner interop.Hash160, addrNetmap, addrContainer []byte) {
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 {
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 {
return token.getSupply(ctx)
}
func BalanceOf(account interop.Hash160) int {
return token.balanceOf(ctx, account)
}
func Transfer(from, to interop.Hash160, amount int, data interface{}) bool {
return token.transfer(ctx, from, to, amount, false, nil)
}
func TransferX(from, to interop.Hash160, amount int, details []byte) bool {
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 {
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 {
multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey)
if !runtime.CheckWitness(multiaddr) {
panic("epochNum: this method must be invoked from inner ring")
}
it := storage.Find(ctx, []byte{}, storage.KeysOnly)
for iterator.Next(it) {
addr := iterator.Value(it).([]byte) // 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 {
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 {
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 binary.Deserialize(data.([]byte)).(Account)
}
return Account{}
}