package client import ( "errors" "fmt" "github.com/nspcc-dev/neo-go/pkg/core/transaction" "github.com/nspcc-dev/neo-go/pkg/encoding/address" "github.com/nspcc-dev/neo-go/pkg/encoding/bigint" "github.com/nspcc-dev/neo-go/pkg/io" "github.com/nspcc-dev/neo-go/pkg/smartcontract" "github.com/nspcc-dev/neo-go/pkg/util" "github.com/nspcc-dev/neo-go/pkg/vm/emit" "github.com/nspcc-dev/neo-go/pkg/vm/opcode" "github.com/nspcc-dev/neo-go/pkg/wallet" ) var ( // NeoContractHash is a hash of the NEO native contract. NeoContractHash, _ = util.Uint160DecodeStringLE("9bde8f209c88dd0e7ca3bf0af0f476cdd8207789") // GasContractHash is a hash of the GAS native contract. GasContractHash, _ = util.Uint160DecodeStringLE("8c23f196d8a1bfd103a9dcb1f9ccf0c611377d3b") ) // NEP5Decimals invokes `decimals` NEP5 method on a specified contract. func (c *Client) NEP5Decimals(tokenHash util.Uint160) (int64, error) { result, err := c.InvokeFunction(tokenHash, "decimals", []smartcontract.Parameter{}, nil) if err != nil { return 0, err } else if result.State != "HALT" || len(result.Stack) == 0 { return 0, errors.New("invalid VM state") } return topIntFromStack(result.Stack) } // NEP5Name invokes `name` NEP5 method on a specified contract. func (c *Client) NEP5Name(tokenHash util.Uint160) (string, error) { result, err := c.InvokeFunction(tokenHash, "name", []smartcontract.Parameter{}, nil) if err != nil { return "", err } else if result.State != "HALT" || len(result.Stack) == 0 { return "", errors.New("invalid VM state") } return topStringFromStack(result.Stack) } // NEP5Symbol invokes `symbol` NEP5 method on a specified contract. func (c *Client) NEP5Symbol(tokenHash util.Uint160) (string, error) { result, err := c.InvokeFunction(tokenHash, "symbol", []smartcontract.Parameter{}, nil) if err != nil { return "", err } else if result.State != "HALT" || len(result.Stack) == 0 { return "", errors.New("invalid VM state") } return topStringFromStack(result.Stack) } // NEP5TotalSupply invokes `totalSupply` NEP5 method on a specified contract. func (c *Client) NEP5TotalSupply(tokenHash util.Uint160) (int64, error) { result, err := c.InvokeFunction(tokenHash, "totalSupply", []smartcontract.Parameter{}, nil) if err != nil { return 0, err } else if result.State != "HALT" || len(result.Stack) == 0 { return 0, errors.New("invalid VM state") } return topIntFromStack(result.Stack) } // NEP5BalanceOf invokes `balanceOf` NEP5 method on a specified contract. func (c *Client) NEP5BalanceOf(tokenHash util.Uint160) (int64, error) { result, err := c.InvokeFunction(tokenHash, "balanceOf", []smartcontract.Parameter{}, nil) if err != nil { return 0, err } else if result.State != "HALT" || len(result.Stack) == 0 { return 0, errors.New("invalid VM state") } return topIntFromStack(result.Stack) } // NEP5TokenInfo returns full NEP5 token info. func (c *Client) NEP5TokenInfo(tokenHash util.Uint160) (*wallet.Token, error) { name, err := c.NEP5Name(tokenHash) if err != nil { return nil, err } symbol, err := c.NEP5Symbol(tokenHash) if err != nil { return nil, err } decimals, err := c.NEP5Decimals(tokenHash) if err != nil { return nil, err } return wallet.NewToken(tokenHash, name, symbol, decimals), nil } // CreateNEP5TransferTx creates an invocation transaction for the 'transfer' // method of a given contract (token) to move specified amount of NEP5 assets // (in FixedN format using contract's number of decimals) to given account and // returns it. The returned transaction is not signed. func (c *Client) CreateNEP5TransferTx(acc *wallet.Account, to util.Uint160, token util.Uint160, amount int64, gas int64) (*transaction.Transaction, error) { from, err := address.StringToUint160(acc.Address) if err != nil { return nil, fmt.Errorf("bad account address: %v", err) } // Note: we don't use invoke function here because it requires // 2 round trips instead of one. w := io.NewBufBinWriter() emit.AppCallWithOperationAndArgs(w.BinWriter, token, "transfer", from, to, amount) emit.Opcode(w.BinWriter, opcode.ASSERT) script := w.Bytes() result, err := c.InvokeScript(script, []transaction.Cosigner{ { Account: from, Scopes: transaction.CalledByEntry, }, }) if err != nil { return nil, fmt.Errorf("can't add system fee to transaction: %v", err) } tx := transaction.New(c.opts.Network, script, result.GasConsumed) tx.Sender = from tx.Cosigners = []transaction.Cosigner{ { Account: from, Scopes: transaction.CalledByEntry, }, } tx.ValidUntilBlock, err = c.CalculateValidUntilBlock() if err != nil { return nil, fmt.Errorf("can't calculate validUntilBlock: %v", err) } err = c.AddNetworkFee(tx, gas, acc) if err != nil { return nil, fmt.Errorf("can't add network fee to transaction: %v", err) } return tx, nil } // TransferNEP5 creates an invocation transaction that invokes 'transfer' method // on a given token to move specified amount of NEP5 assets (in FixedN format // using contract's number of decimals) to given account and sends it to the // network returning just a hash of it. func (c *Client) TransferNEP5(acc *wallet.Account, to util.Uint160, token util.Uint160, amount int64, gas int64) (util.Uint256, error) { tx, err := c.CreateNEP5TransferTx(acc, to, token, amount, gas) if err != nil { return util.Uint256{}, err } if err := acc.SignTx(tx); err != nil { return util.Uint256{}, fmt.Errorf("can't sign tx: %v", err) } if err := c.SendRawTransaction(tx); err != nil { return util.Uint256{}, err } return tx.Hash(), nil } func topIntFromStack(st []smartcontract.Parameter) (int64, error) { index := len(st) - 1 // top stack element is last in the array var decimals int64 switch typ := st[index].Type; typ { case smartcontract.IntegerType: var ok bool decimals, ok = st[index].Value.(int64) if !ok { return 0, errors.New("invalid Integer item") } case smartcontract.ByteArrayType: data, ok := st[index].Value.([]byte) if !ok { return 0, errors.New("invalid ByteArray item") } decimals = bigint.FromBytes(data).Int64() default: return 0, fmt.Errorf("invalid stack item type: %s", typ) } return decimals, nil } func topStringFromStack(st []smartcontract.Parameter) (string, error) { index := len(st) - 1 // top stack element is last in the array var s string switch typ := st[index].Type; typ { case smartcontract.StringType: var ok bool s, ok = st[index].Value.(string) if !ok { return "", errors.New("invalid String item") } case smartcontract.ByteArrayType: data, ok := st[index].Value.([]byte) if !ok { return "", errors.New("invalid ByteArray item") } s = string(data) default: return "", fmt.Errorf("invalid stack item type: %s", typ) } return s, nil }