frostfs-contract/balance/balance_contract.go

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package balance
import (
"github.com/nspcc-dev/neo-go/pkg/interop"
"github.com/nspcc-dev/neo-go/pkg/interop/contract"
"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 structure stores metadata of each NeoFS balance account.
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"
netmapContractKey = "netmapScriptHash"
containerContractKey = "containerScriptHash"
notaryDisabledKey = "notary"
)
var token Token
func createToken() Token {
return Token{
Symbol: symbol,
Decimals: decimals,
CirculationKey: circulation,
}
}
func init() {
token = createToken()
}
func _deploy(data interface{}, isUpdate bool) {
if isUpdate {
return
}
args := data.(struct {
notaryDisabled bool
addrNetmap interop.Hash160
addrContainer interop.Hash160
})
ctx := storage.GetContext()
if len(args.addrNetmap) != interop.Hash160Len || len(args.addrContainer) != interop.Hash160Len {
panic("incorrect length of contract script hash")
}
storage.Put(ctx, netmapContractKey, args.addrNetmap)
storage.Put(ctx, containerContractKey, args.addrContainer)
// initialize the way to collect signatures
storage.Put(ctx, notaryDisabledKey, args.notaryDisabled)
if args.notaryDisabled {
common.InitVote(ctx)
runtime.Log("balance contract notary disabled")
}
runtime.Log("balance contract initialized")
}
// Update method updates contract source code and manifest. Can be invoked
// only by committee.
func Update(script []byte, manifest []byte, data interface{}) {
if !common.HasUpdateAccess() {
panic("only committee can update contract")
}
contract.Call(interop.Hash160(management.Hash), "update",
contract.All, script, manifest, common.AppendVersion(data))
runtime.Log("balance contract updated")
}
// Symbol is a NEP-17 standard method that returns NEOFS token symbol.
func Symbol() string {
return token.Symbol
}
// Decimals is a NEP-17 standard method that returns precision of NeoFS
// balances.
func Decimals() int {
return token.Decimals
}
// TotalSupply is a NEP-17 standard method that returns total amount of main
// chain GAS in the NeoFS network.
func TotalSupply() int {
ctx := storage.GetReadOnlyContext()
return token.getSupply(ctx)
}
// BalanceOf is a NEP-17 standard method that returns NeoFS balance of specified
// account.
func BalanceOf(account interop.Hash160) int {
ctx := storage.GetReadOnlyContext()
return token.balanceOf(ctx, account)
}
// Transfer is a NEP-17 standard method that transfers NeoFS balance from one
// account to other. Can be invoked only by account owner.
//
// Produces Transfer and TransferX notifications. TransferX notification
// will have empty details field.
func Transfer(from, to interop.Hash160, amount int, data interface{}) bool {
ctx := storage.GetContext()
return token.transfer(ctx, from, to, amount, false, nil)
}
// TransferX is a method for NeoFS balance transfers from one account to
// another. Can be invoked by account owner or by Alphabet nodes.
//
// Produces Transfer and TransferX notifications.
//
// TransferX method expands Transfer method by having extra details argument.
// Also TransferX method allows to transfer assets by Alphabet nodes of the
// Inner Ring with multi signature.
func TransferX(from, to interop.Hash160, amount int, details []byte) {
ctx := storage.GetContext()
notaryDisabled := storage.Get(ctx, notaryDisabledKey).(bool)
var ( // for invocation collection without notary
alphabet []common.IRNode
nodeKey []byte
indirectCall bool
)
if notaryDisabled {
alphabet = common.AlphabetNodes()
nodeKey = common.InnerRingInvoker(alphabet)
if len(nodeKey) == 0 {
panic("this method must be invoked from inner ring")
}
indirectCall = common.FromKnownContract(
ctx,
runtime.GetCallingScriptHash(),
containerContractKey,
)
} else {
multiaddr := common.AlphabetAddress()
common.CheckAlphabetWitness(multiaddr)
}
if notaryDisabled && !indirectCall {
threshold := len(alphabet)*2/3 + 1
id := common.InvokeID([]interface{}{from, to, amount}, []byte("transfer"))
n := common.Vote(ctx, id, nodeKey)
if n < threshold {
return
}
common.RemoveVotes(ctx, id)
}
result := token.transfer(ctx, from, to, amount, true, details)
if !result {
panic("can't transfer assets")
}
runtime.Log("successfully transferred assets")
}
// Lock is a method that transfers assets from user account to lock account
// related to the user. Can be invoked only by Alphabet nodes of the Inner Ring.
//
// Produces Lock, Transfer and TransferX notifications.
//
// Lock method invoked by Alphabet nodes of the Inner Ring when they process
// Withdraw notification from NeoFS contract. This should transfer assets
// to new lock account that won't be used for anything besides Unlock and Burn.
func Lock(txDetails []byte, from, to interop.Hash160, amount, until int) {
ctx := storage.GetContext()
notaryDisabled := storage.Get(ctx, notaryDisabledKey).(bool)
var ( // for invocation collection without notary
alphabet []common.IRNode
nodeKey []byte
)
if notaryDisabled {
alphabet = common.AlphabetNodes()
nodeKey = common.InnerRingInvoker(alphabet)
if len(nodeKey) == 0 {
panic("this method must be invoked from inner ring")
}
} else {
multiaddr := common.AlphabetAddress()
common.CheckAlphabetWitness(multiaddr)
}
details := common.LockTransferDetails(txDetails)
lockAccount := Account{
Balance: 0,
Until: until,
Parent: from,
}
if notaryDisabled {
threshold := len(alphabet)*2/3 + 1
id := common.InvokeID([]interface{}{txDetails}, []byte("lock"))
n := common.Vote(ctx, id, nodeKey)
if n < threshold {
return
}
common.RemoveVotes(ctx, id)
}
common.SetSerialized(ctx, to, lockAccount)
result := token.transfer(ctx, from, to, amount, true, details)
if !result {
// consider using `return false` to remove votes
panic("can't lock funds")
}
runtime.Log("created lock account")
runtime.Notify("Lock", txDetails, from, to, amount, until)
}
// NewEpoch is a method that checks timeout on lock accounts and return assets
// if lock is not available anymore. Can be invoked only by NewEpoch method
// of Netmap contract.
//
// Produces Transfer and TransferX notifications.
func NewEpoch(epochNum int) {
ctx := storage.GetContext()
notaryDisabled := storage.Get(ctx, notaryDisabledKey).(bool)
if notaryDisabled {
indirectCall := common.FromKnownContract(
ctx,
runtime.GetCallingScriptHash(),
netmapContractKey,
)
if !indirectCall {
panic("this method must be invoked from inner ring")
}
} else {
multiaddr := common.AlphabetAddress()
common.CheckAlphabetWitness(multiaddr)
}
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) != interop.Hash160Len {
continue
}
acc := getAccount(ctx, addr)
if acc.Until == 0 {
continue
}
if epochNum >= acc.Until {
details := common.UnlockTransferDetails(epochNum)
// return assets back to the parent
token.transfer(ctx, addr, acc.Parent, acc.Balance, true, details)
}
}
}
// Mint is a method that transfers assets to user account from empty account.
// Can be invoked only by Alphabet nodes of the Inner Ring.
//
// Produces Mint, Transfer and TransferX notifications.
//
// Mint method invoked by Alphabet nodes of the Inner Ring when they process
// Deposit notification from NeoFS contract. Before that Alphabet nodes should
// synchronize precision of main chain GAS contract and Balance contract.
// Mint increases total supply of NEP-17 compatible NeoFS token.
func Mint(to interop.Hash160, amount int, txDetails []byte) {
ctx := storage.GetContext()
notaryDisabled := storage.Get(ctx, notaryDisabledKey).(bool)
var ( // for invocation collection without notary
alphabet []common.IRNode
nodeKey []byte
)
if notaryDisabled {
alphabet = common.AlphabetNodes()
nodeKey = common.InnerRingInvoker(alphabet)
if len(nodeKey) == 0 {
panic("this method must be invoked from inner ring")
}
} else {
multiaddr := common.AlphabetAddress()
common.CheckAlphabetWitness(multiaddr)
}
details := common.MintTransferDetails(txDetails)
if notaryDisabled {
threshold := len(alphabet)*2/3 + 1
id := common.InvokeID([]interface{}{txDetails}, []byte("mint"))
n := common.Vote(ctx, id, nodeKey)
if n < threshold {
return
}
common.RemoveVotes(ctx, id)
}
ok := token.transfer(ctx, nil, to, amount, true, details)
if !ok {
panic("can't transfer assets")
}
supply := token.getSupply(ctx)
supply = supply + amount
storage.Put(ctx, token.CirculationKey, supply)
runtime.Log("assets were minted")
runtime.Notify("Mint", to, amount)
}
// Burn is a method that transfers assets from user account to empty account.
// Can be invoked only by Alphabet nodes of the Inner Ring.
//
// Produces Burn, Transfer and TransferX notifications.
//
// Burn method invoked by Alphabet nodes of the Inner Ring when they process
// Cheque notification from NeoFS contract. It means that locked assets were
// transferred to user in main chain, therefore lock account should be destroyed.
// Before that Alphabet nodes should synchronize precision of main chain GAS
// contract and Balance contract. Burn decreases total supply of NEP-17
// compatible NeoFS token.
func Burn(from interop.Hash160, amount int, txDetails []byte) {
ctx := storage.GetContext()
notaryDisabled := storage.Get(ctx, notaryDisabledKey).(bool)
var ( // for invocation collection without notary
alphabet []common.IRNode
nodeKey []byte
)
if notaryDisabled {
alphabet = common.AlphabetNodes()
nodeKey = common.InnerRingInvoker(alphabet)
if len(nodeKey) == 0 {
panic("this method must be invoked from inner ring")
}
} else {
multiaddr := common.AlphabetAddress()
common.CheckAlphabetWitness(multiaddr)
}
details := common.BurnTransferDetails(txDetails)
if notaryDisabled {
threshold := len(alphabet)*2/3 + 1
id := common.InvokeID([]interface{}{txDetails}, []byte("burn"))
n := common.Vote(ctx, id, nodeKey)
if n < threshold {
return
}
common.RemoveVotes(ctx, id)
}
ok := token.transfer(ctx, from, nil, amount, true, details)
if !ok {
panic("can't transfer assets")
}
supply := token.getSupply(ctx)
if supply < amount {
panic("negative supply after burn")
}
supply = supply - amount
storage.Put(ctx, token.CirculationKey, supply)
runtime.Log("assets were burned")
runtime.Notify("Burn", from, amount)
}
// Version returns version of the contract.
func Version() int {
return common.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) != interop.Hash160Len || !isUsableAddress(from) {
runtime.Log("bad script hashes")
return emptyAcc, false
}
} else if len(from) == 0 {
return emptyAcc, true
}
amountFrom := getAccount(ctx, from)
if amountFrom.Balance < amount {
runtime.Log("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{}
}