wallet: allow to add token contracts to the wallet

pkg/wallet/token.go

@@ -0,0 +1,60 @@
+package wallet
+
+import (
+	"encoding/json"
+
+	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+)
+
+// Token represents imported token contract.
+type Token struct {
+	Name     string
+	Hash     util.Uint160
+	Decimals int64
+	Symbol   string
+	Address  string
+}
+
+type tokenAux struct {
+	Name     string       `json:"name"`
+	Hash     util.Uint160 `json:"script_hash"`
+	Decimals int64        `json:"decimals"`
+	Symbol   string       `json:"symbol"`
+}
+
+// NewToken returns new token contract info.
+func NewToken(tokenHash util.Uint160, name, symbol string, decimals int64) *Token {
+	return &Token{
+		Name:     name,
+		Hash:     tokenHash,
+		Decimals: decimals,
+		Symbol:   symbol,
+		Address:  address.Uint160ToString(tokenHash),
+	}
+}
+
+// MarshalJSON implements json.Marshaler interface.
+func (t *Token) MarshalJSON() ([]byte, error) {
+	m := &tokenAux{
+		Name:     t.Name,
+		Hash:     t.Hash.Reverse(), // address should be marshaled in LE but default marshaler uses BE.
+		Decimals: t.Decimals,
+		Symbol:   t.Symbol,
+	}
+	return json.Marshal(m)
+}
+
+// UnmarshalJSON implements json.Unmarshaler interface.
+func (t *Token) UnmarshalJSON(data []byte) error {
+	aux := new(tokenAux)
+	if err := json.Unmarshal(data, aux); err != nil {
+		return err
+	}
+	t.Name = aux.Name
+	t.Hash = aux.Hash.Reverse()
+	t.Decimals = aux.Decimals
+	t.Symbol = aux.Symbol
+	t.Address = address.Uint160ToString(t.Hash)
+	return nil
+}

pkg/wallet/token_test.go

@@ -0,0 +1,29 @@
+package wallet
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/stretchr/testify/require"
+)
+
+func TestToken_MarshalJSON(t *testing.T) {
+	// From the https://neo-python.readthedocs.io/en/latest/prompt.html#import-nep5-compliant-token
+	h, err := util.Uint160DecodeStringLE("f8d448b227991cf07cb96a6f9c0322437f1599b9")
+	require.NoError(t, err)
+
+	tok := NewToken(h, "NEP5 Standard", "NEP5", 8)
+	require.Equal(t, "NEP5 Standard", tok.Name)
+	require.Equal(t, "NEP5", tok.Symbol)
+	require.EqualValues(t, 8, tok.Decimals)
+	require.Equal(t, h, tok.Hash)
+	require.Equal(t, "AYhE3Svuqdfh1RtzvE8hUhNR7HSpaSDFQg", tok.Address)
+
+	data, err := json.Marshal(tok)
+	require.NoError(t, err)
+
+	actual := new(Token)
+	require.NoError(t, json.Unmarshal(data, actual))
+	require.Equal(t, tok, actual)
+}

pkg/wallet/wallet.go

@@ -28,7 +28,7 @@ type Wallet struct {
 
 	// Extra metadata can be used for storing arbitrary data.
 	// This field can be empty.
-	Extra interface{} `json:"extra"`
+	Extra Extra `json:"extra"`
 
 	// Path where the wallet file is located..
 	path string
@@ -37,6 +37,12 @@ type Wallet struct {
 	rw io.ReadWriter
 }
 
+// Extra stores imported token contracts.
+type Extra struct {
+	// Tokens is a list of imported token contracts.
+	Tokens []*Token
+}
+
 // NewWallet creates a new NEO wallet at the given location.
 func NewWallet(location string) (*Wallet, error) {
 	file, err := os.Create(location)
@@ -96,6 +102,11 @@ func (w *Wallet) AddAccount(acc *Account) {
 	w.Accounts = append(w.Accounts, acc)
 }
 
+// AddToken adds new token to a wallet.
+func (w *Wallet) AddToken(tok *Token) {
+	w.Extra.Tokens = append(w.Extra.Tokens, tok)
+}
+
 // Path returns the location of the wallet on the filesystem.
 func (w *Wallet) Path() string {
 	return w.path