neoneo-go/pkg/core/native/native_nep17.go
Anna Shaleva 58ab3b5ad1 core: get native nep17 balance from contract storage
Not from DAO's items with storage.STNEP17Balances prefix, because
changes are reflected there only after notifications processing. And
this happens only after the transaction script is executed, but there
might be cases when we need to get the balance that was updated
earlier during the same transaction processing.

Affects storage dumps.
2021-04-01 18:37:44 +03:00

331 lines
8.8 KiB
Go

package native
import (
"errors"
"fmt"
"math"
"math/big"
"github.com/nspcc-dev/neo-go/pkg/core/dao"
"github.com/nspcc-dev/neo-go/pkg/core/interop"
"github.com/nspcc-dev/neo-go/pkg/core/interop/contract"
"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
"github.com/nspcc-dev/neo-go/pkg/core/state"
"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
"github.com/nspcc-dev/neo-go/pkg/smartcontract"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
// prefixAccount is the standard prefix used to store account data.
const prefixAccount = 20
// makeAccountKey creates a key from account script hash.
func makeAccountKey(h util.Uint160) []byte {
return makeUint160Key(prefixAccount, h)
}
// nep17TokenNative represents NEP-17 token contract.
type nep17TokenNative struct {
interop.ContractMD
symbol string
decimals int64
factor int64
incBalance func(*interop.Context, util.Uint160, *state.StorageItem, *big.Int) error
balFromBytes func(item *state.StorageItem) (*big.Int, error)
}
// totalSupplyKey is the key used to store totalSupply value.
var totalSupplyKey = []byte{11}
func (c *nep17TokenNative) Metadata() *interop.ContractMD {
return &c.ContractMD
}
func newNEP17Native(name string, id int32) *nep17TokenNative {
n := &nep17TokenNative{ContractMD: *interop.NewContractMD(name, id)}
n.Manifest.SupportedStandards = []string{manifest.NEP17StandardName}
desc := newDescriptor("symbol", smartcontract.StringType)
md := newMethodAndPrice(n.Symbol, 0, callflag.NoneFlag)
n.AddMethod(md, desc)
desc = newDescriptor("decimals", smartcontract.IntegerType)
md = newMethodAndPrice(n.Decimals, 0, callflag.NoneFlag)
n.AddMethod(md, desc)
desc = newDescriptor("totalSupply", smartcontract.IntegerType)
md = newMethodAndPrice(n.TotalSupply, 1<<15, callflag.ReadStates)
n.AddMethod(md, desc)
desc = newDescriptor("balanceOf", smartcontract.IntegerType,
manifest.NewParameter("account", smartcontract.Hash160Type))
md = newMethodAndPrice(n.balanceOf, 1<<15, callflag.ReadStates)
n.AddMethod(md, desc)
transferParams := []manifest.Parameter{
manifest.NewParameter("from", smartcontract.Hash160Type),
manifest.NewParameter("to", smartcontract.Hash160Type),
manifest.NewParameter("amount", smartcontract.IntegerType),
}
desc = newDescriptor("transfer", smartcontract.BoolType,
append(transferParams, manifest.NewParameter("data", smartcontract.AnyType))...,
)
md = newMethodAndPrice(n.Transfer, 1<<17, callflag.States|callflag.AllowCall|callflag.AllowNotify)
md.StorageFee = 50
n.AddMethod(md, desc)
n.AddEvent("Transfer", transferParams...)
return n
}
func (c *nep17TokenNative) Initialize(_ *interop.Context) error {
return nil
}
func (c *nep17TokenNative) Symbol(_ *interop.Context, _ []stackitem.Item) stackitem.Item {
return stackitem.NewByteArray([]byte(c.symbol))
}
func (c *nep17TokenNative) Decimals(_ *interop.Context, _ []stackitem.Item) stackitem.Item {
return stackitem.NewBigInteger(big.NewInt(c.decimals))
}
func (c *nep17TokenNative) TotalSupply(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
return stackitem.NewBigInteger(c.getTotalSupply(ic.DAO))
}
func (c *nep17TokenNative) getTotalSupply(d dao.DAO) *big.Int {
si := d.GetStorageItem(c.ID, totalSupplyKey)
if si == nil {
return big.NewInt(0)
}
return bigint.FromBytes(si)
}
func (c *nep17TokenNative) saveTotalSupply(d dao.DAO, supply *big.Int) error {
return d.PutStorageItem(c.ID, totalSupplyKey, bigint.ToBytes(supply))
}
func (c *nep17TokenNative) Transfer(ic *interop.Context, args []stackitem.Item) stackitem.Item {
from := toUint160(args[0])
to := toUint160(args[1])
amount := toBigInt(args[2])
err := c.TransferInternal(ic, from, to, amount, args[3])
return stackitem.NewBool(err == nil)
}
func addrToStackItem(u *util.Uint160) stackitem.Item {
if u == nil {
return stackitem.Null{}
}
return stackitem.NewByteArray(u.BytesBE())
}
func (c *nep17TokenNative) postTransfer(ic *interop.Context, from, to *util.Uint160, amount *big.Int,
data stackitem.Item, callOnPayment bool) {
c.emitTransfer(ic, from, to, amount)
if to == nil || !callOnPayment {
return
}
cs, err := ic.GetContract(*to)
if err != nil {
return
}
fromArg := stackitem.Item(stackitem.Null{})
if from != nil {
fromArg = stackitem.NewByteArray((*from).BytesBE())
}
args := []stackitem.Item{
fromArg,
stackitem.NewBigInteger(amount),
data,
}
if err := contract.CallFromNative(ic, c.Hash, cs, manifest.MethodOnNEP17Payment, args, false); err != nil {
panic(err)
}
}
func (c *nep17TokenNative) emitTransfer(ic *interop.Context, from, to *util.Uint160, amount *big.Int) {
ne := state.NotificationEvent{
ScriptHash: c.Hash,
Name: "Transfer",
Item: stackitem.NewArray([]stackitem.Item{
addrToStackItem(from),
addrToStackItem(to),
stackitem.NewBigInteger(amount),
}),
}
ic.Notifications = append(ic.Notifications, ne)
}
func (c *nep17TokenNative) updateAccBalance(ic *interop.Context, acc util.Uint160, amount *big.Int) error {
key := makeAccountKey(acc)
si := ic.DAO.GetStorageItem(c.ID, key)
if si == nil {
if amount.Sign() <= 0 {
return errors.New("insufficient funds")
}
si = state.StorageItem{}
}
err := c.incBalance(ic, acc, &si, amount)
if err != nil {
return err
}
if si == nil {
err = ic.DAO.DeleteStorageItem(c.ID, key)
} else {
err = ic.DAO.PutStorageItem(c.ID, key, si)
}
return err
}
// TransferInternal transfers NEO between accounts.
func (c *nep17TokenNative) TransferInternal(ic *interop.Context, from, to util.Uint160, amount *big.Int, data stackitem.Item) error {
if amount.Sign() == -1 {
return errors.New("negative amount")
}
caller := ic.VM.GetCallingScriptHash()
if caller.Equals(util.Uint160{}) || !from.Equals(caller) {
ok, err := runtime.CheckHashedWitness(ic, from)
if err != nil {
return err
} else if !ok {
return errors.New("invalid signature")
}
}
isEmpty := from.Equals(to) || amount.Sign() == 0
inc := amount
if isEmpty {
inc = big.NewInt(0)
} else {
inc = new(big.Int).Neg(inc)
}
if err := c.updateAccBalance(ic, from, inc); err != nil {
return err
}
if !isEmpty {
if err := c.updateAccBalance(ic, to, amount); err != nil {
return err
}
}
c.postTransfer(ic, &from, &to, amount, data, true)
return nil
}
func (c *nep17TokenNative) balanceOf(ic *interop.Context, args []stackitem.Item) stackitem.Item {
h := toUint160(args[0])
key := makeAccountKey(h)
si := ic.DAO.GetStorageItem(c.ID, key)
if si == nil {
return stackitem.NewBigInteger(big.NewInt(0))
}
balance, err := c.balFromBytes(&si)
if err != nil {
panic(fmt.Errorf("can not deserialize balance state: %w", err))
}
return stackitem.NewBigInteger(balance)
}
func (c *nep17TokenNative) mint(ic *interop.Context, h util.Uint160, amount *big.Int, callOnPayment bool) {
if amount.Sign() == 0 {
return
}
c.addTokens(ic, h, amount)
c.postTransfer(ic, nil, &h, amount, stackitem.Null{}, callOnPayment)
}
func (c *nep17TokenNative) burn(ic *interop.Context, h util.Uint160, amount *big.Int) {
if amount.Sign() == 0 {
return
}
c.addTokens(ic, h, new(big.Int).Neg(amount))
c.postTransfer(ic, &h, nil, amount, stackitem.Null{}, false)
}
func (c *nep17TokenNative) addTokens(ic *interop.Context, h util.Uint160, amount *big.Int) {
if amount.Sign() == 0 {
return
}
key := makeAccountKey(h)
si := ic.DAO.GetStorageItem(c.ID, key)
if si == nil {
si = state.StorageItem{}
}
if err := c.incBalance(ic, h, &si, amount); err != nil {
panic(err)
}
var err error
if si == nil {
err = ic.DAO.DeleteStorageItem(c.ID, key)
} else {
err = ic.DAO.PutStorageItem(c.ID, key, si)
}
if err != nil {
panic(err)
}
supply := c.getTotalSupply(ic.DAO)
supply.Add(supply, amount)
err = c.saveTotalSupply(ic.DAO, supply)
if err != nil {
panic(err)
}
}
func newDescriptor(name string, ret smartcontract.ParamType, ps ...manifest.Parameter) *manifest.Method {
return &manifest.Method{
Name: name,
Parameters: ps,
ReturnType: ret,
}
}
func newMethodAndPrice(f interop.Method, cpuFee int64, flags callflag.CallFlag) *interop.MethodAndPrice {
return &interop.MethodAndPrice{
Func: f,
CPUFee: cpuFee,
RequiredFlags: flags,
}
}
func toBigInt(s stackitem.Item) *big.Int {
bi, err := s.TryInteger()
if err != nil {
panic(err)
}
return bi
}
func toUint160(s stackitem.Item) util.Uint160 {
buf, err := s.TryBytes()
if err != nil {
panic(err)
}
u, err := util.Uint160DecodeBytesBE(buf)
if err != nil {
panic(err)
}
return u
}
func toUint32(s stackitem.Item) uint32 {
bigInt := toBigInt(s)
if !bigInt.IsInt64() {
panic("bigint is not an int64")
}
int64Value := bigInt.Int64()
if int64Value < 0 || int64Value > math.MaxUint32 {
panic("bigint does not fit into uint32")
}
return uint32(int64Value)
}