neo-go/pkg/core/native/native_nep5.go
Roman Khimov 30836ca69b core/native: untangle native contracts initialization
The notion of NativeContractState shouldn't ever existed, native contract is a
contract and its state is saved as regular contract state which is critical
because we'll have MPT calculations over this state soon.

Initial minting should be done in Neo.Native.Deploy because it generates
notification that should have proper transaction context.

RegisterNative() shouldn't exist as a public method, native contracts are only
registered at block 0 and they can do it internally, no outside user should be
able to mess with it.

Move some structures from `native` package to `interop` also to avoid circular
references as interop.Context has to have a list of native contracts (exposing
them via Blockchainer is again too dangerous, it's too powerful tool).
2020-04-27 12:30:39 +03:00

258 lines
6.7 KiB
Go

package native
import (
"errors"
"math/big"
"github.com/nspcc-dev/neo-go/pkg/core/interop"
"github.com/nspcc-dev/neo-go/pkg/core/state"
"github.com/nspcc-dev/neo-go/pkg/smartcontract"
"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"
"github.com/nspcc-dev/neo-go/pkg/vm/emit"
)
// nep5TokenNative represents NEP-5 token contract.
type nep5TokenNative struct {
interop.ContractMD
name string
symbol string
decimals int64
factor int64
onPersist func(*interop.Context) error
incBalance func(*interop.Context, *state.Account, *big.Int) error
}
// totalSupplyKey is the key used to store totalSupply value.
var totalSupplyKey = []byte{11}
func (c *nep5TokenNative) Metadata() *interop.ContractMD {
return &c.ContractMD
}
var _ interop.Contract = (*nep5TokenNative)(nil)
func newNEP5Native(name string) *nep5TokenNative {
n := &nep5TokenNative{ContractMD: *interop.NewContractMD(name)}
desc := newDescriptor("name", smartcontract.StringType)
md := newMethodAndPrice(n.Name, 1, smartcontract.NoneFlag)
n.AddMethod(md, desc, true)
desc = newDescriptor("symbol", smartcontract.StringType)
md = newMethodAndPrice(n.Symbol, 1, smartcontract.NoneFlag)
n.AddMethod(md, desc, true)
desc = newDescriptor("decimals", smartcontract.IntegerType)
md = newMethodAndPrice(n.Decimals, 1, smartcontract.NoneFlag)
n.AddMethod(md, desc, true)
desc = newDescriptor("totalSupply", smartcontract.IntegerType)
md = newMethodAndPrice(n.TotalSupply, 1, smartcontract.NoneFlag)
n.AddMethod(md, desc, true)
desc = newDescriptor("balanceOf", smartcontract.IntegerType,
manifest.NewParameter("account", smartcontract.Hash160Type))
md = newMethodAndPrice(n.balanceOf, 1, smartcontract.NoneFlag)
n.AddMethod(md, desc, true)
desc = newDescriptor("transfer", smartcontract.BoolType,
manifest.NewParameter("from", smartcontract.Hash160Type),
manifest.NewParameter("to", smartcontract.Hash160Type),
manifest.NewParameter("amount", smartcontract.IntegerType),
)
md = newMethodAndPrice(n.Transfer, 1, smartcontract.NoneFlag)
n.AddMethod(md, desc, false)
n.AddEvent("Transfer", desc.Parameters...)
return n
}
func (c *nep5TokenNative) Initialize(_ *interop.Context) error {
return nil
}
func (c *nep5TokenNative) Name(_ *interop.Context, _ []vm.StackItem) vm.StackItem {
return vm.NewByteArrayItem([]byte(c.name))
}
func (c *nep5TokenNative) Symbol(_ *interop.Context, _ []vm.StackItem) vm.StackItem {
return vm.NewByteArrayItem([]byte(c.symbol))
}
func (c *nep5TokenNative) Decimals(_ *interop.Context, _ []vm.StackItem) vm.StackItem {
return vm.NewBigIntegerItem(big.NewInt(c.decimals))
}
func (c *nep5TokenNative) TotalSupply(ic *interop.Context, _ []vm.StackItem) vm.StackItem {
return vm.NewBigIntegerItem(c.getTotalSupply(ic))
}
func (c *nep5TokenNative) getTotalSupply(ic *interop.Context) *big.Int {
si := ic.DAO.GetStorageItem(c.Hash, totalSupplyKey)
if si == nil {
return big.NewInt(0)
}
return emit.BytesToInt(si.Value)
}
func (c *nep5TokenNative) saveTotalSupply(ic *interop.Context, supply *big.Int) error {
si := &state.StorageItem{Value: emit.IntToBytes(supply)}
return ic.DAO.PutStorageItem(c.Hash, totalSupplyKey, si)
}
func (c *nep5TokenNative) Transfer(ic *interop.Context, args []vm.StackItem) vm.StackItem {
from := toUint160(args[0])
to := toUint160(args[1])
amount := toBigInt(args[2])
err := c.transfer(ic, from, to, amount)
return vm.NewBoolItem(err == nil)
}
func addrToStackItem(u *util.Uint160) vm.StackItem {
if u == nil {
return nil
}
return vm.NewByteArrayItem(u.BytesBE())
}
func (c *nep5TokenNative) emitTransfer(ic *interop.Context, from, to *util.Uint160, amount *big.Int) {
ne := state.NotificationEvent{
ScriptHash: c.Hash,
Item: vm.NewArrayItem([]vm.StackItem{
vm.NewByteArrayItem([]byte("Transfer")),
addrToStackItem(from),
addrToStackItem(to),
vm.NewBigIntegerItem(amount),
}),
}
ic.Notifications = append(ic.Notifications, ne)
}
func (c *nep5TokenNative) transfer(ic *interop.Context, from, to util.Uint160, amount *big.Int) error {
if amount.Sign() == -1 {
return errors.New("negative amount")
}
accFrom, err := ic.DAO.GetAccountStateOrNew(from)
if err != nil {
return err
}
isEmpty := from.Equals(to) || amount.Sign() == 0
inc := amount
if isEmpty {
inc = big.NewInt(0)
}
if err := c.incBalance(ic, accFrom, inc); err != nil {
return err
}
if err := ic.DAO.PutAccountState(accFrom); err != nil {
return err
}
if !isEmpty {
accTo, err := ic.DAO.GetAccountStateOrNew(to)
if err != nil {
return err
}
if err := c.incBalance(ic, accTo, amount); err != nil {
return err
}
if err := ic.DAO.PutAccountState(accTo); err != nil {
return err
}
}
c.emitTransfer(ic, &from, &to, amount)
return nil
}
func (c *nep5TokenNative) balanceOf(ic *interop.Context, args []vm.StackItem) vm.StackItem {
h := toUint160(args[0])
bs, err := ic.DAO.GetNEP5Balances(h)
if err != nil {
panic(err)
}
balance := bs.Trackers[c.Hash].Balance
return vm.NewBigIntegerItem(big.NewInt(balance))
}
func (c *nep5TokenNative) mint(ic *interop.Context, h util.Uint160, amount *big.Int) {
c.addTokens(ic, h, amount)
c.emitTransfer(ic, nil, &h, amount)
}
func (c *nep5TokenNative) burn(ic *interop.Context, h util.Uint160, amount *big.Int) {
amount = new(big.Int).Neg(amount)
c.addTokens(ic, h, amount)
c.emitTransfer(ic, &h, nil, amount)
}
func (c *nep5TokenNative) addTokens(ic *interop.Context, h util.Uint160, amount *big.Int) {
if sign := amount.Sign(); sign == -1 {
panic("negative amount")
} else if sign == 0 {
return
}
acc, err := ic.DAO.GetAccountStateOrNew(h)
if err != nil {
panic(err)
}
if err := c.incBalance(ic, acc, amount); err != nil {
panic(err)
}
if err := ic.DAO.PutAccountState(acc); err != nil {
panic(err)
}
supply := c.getTotalSupply(ic)
supply.Add(supply, amount)
err = c.saveTotalSupply(ic, supply)
if err != nil {
panic(err)
}
}
func (c *nep5TokenNative) OnPersist(ic *interop.Context) error {
return c.onPersist(ic)
}
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, price int64, flags smartcontract.CallFlag) *interop.MethodAndPrice {
return &interop.MethodAndPrice{
Func: f,
Price: price,
RequiredFlags: flags,
}
}
func toBigInt(s vm.StackItem) *big.Int {
bi, err := s.TryInteger()
if err != nil {
panic(err)
}
return bi
}
func toUint160(s vm.StackItem) util.Uint160 {
buf, err := s.TryBytes()
if err != nil {
panic(err)
}
u, err := util.Uint160DecodeBytesBE(buf)
if err != nil {
panic(err)
}
return u
}