Null safe migration

example/main.dart

@@ -75,7 +75,7 @@ void main() async {
         "original_amount": utxo.satoshis
       });
 
-      totalBalance += utxo.satoshis;
+      totalBalance += utxo.satoshis!;
     });
 
     // set an address to send the remaining balance to

lib/src/account.dart

@@ -4,25 +4,31 @@ import 'hdnode.dart';
 class Account {
   final HDNode accountNode;
 
-  int currentChild = 0;
+  int? currentChild = 0;
 
   Account(this.accountNode, [this.currentChild]);
 
   /// Returns address at the current position
-  String getCurrentAddress([legacyFormat = true]) {
+  String? getCurrentAddress([legacyFormat = true]) {
     if (legacyFormat) {
-      return accountNode.derive(currentChild).toLegacyAddress();
+      return accountNode.derive(currentChild!).toLegacyAddress();
     } else {
-      return accountNode.derive(currentChild).toCashAddress();
+      return accountNode.derive(currentChild!).toCashAddress();
     }
   }
 
   /// moves the position forward and returns an address from the new position
-  String getNextAddress([legacyFormat = true]) {
+  String? getNextAddress([legacyFormat = true]) {
     if (legacyFormat) {
-      return accountNode.derive(++currentChild).toLegacyAddress();
+      if (currentChild != null) {
+        currentChild = currentChild! + 1;
+        return accountNode.derive(currentChild!).toLegacyAddress();
+      }
     } else {
-      return accountNode.derive(++currentChild).toCashAddress();
+      if (currentChild != null) {
+        currentChild = currentChild! + 1;
+        return accountNode.derive(currentChild!).toCashAddress();
+      }
     }
   }
 }

lib/src/address.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:convert';
 import 'dart:typed_data';
 import 'utils/rest_api.dart';
@@ -54,8 +55,9 @@ class Address {
   /// Returns information about the given Bitcoin Cash address.
   ///
   /// See https://developer.bitcoin.com/bitbox/docs/util for details about returned format
-  static Future<Map<String, dynamic>> validateAddress(String address) async =>
-      await RestApi.sendGetRequest("util/validateAddress", address);
+  static Future<Map<String, dynamic>?> validateAddress(String address) async =>
+      await (RestApi.sendGetRequest("util/validateAddress", address)
+          as FutureOr<Map<String, dynamic>?>);
 
   /// Returns details of the provided address or addresses
   ///
@@ -90,7 +92,7 @@ class Address {
       return Utxo.convertMapListToUtxos(result["utxos"]);
     } else if (result is List<Map>) {
       final returnList = <Map>[];
-      final returnMap = <String, List>{};
+      final returnMap = <String?, List>{};
 
       result.forEach((addressUtxoMap) {
         if (returnAsMap) {
@@ -123,7 +125,7 @@ class Address {
       return Utxo.convertMapListToUtxos(result["utxos"]);
     } else if (result is List) {
       final returnList = <Map>[];
-      final returnMap = <String, List>{};
+      final returnMap = <String?, List>{};
 
       result.forEach((addressUtxoMap) {
         if (returnAsMap) {
@@ -147,7 +149,7 @@ class Address {
     final decoded = _decode(address);
     final testnet =
         decoded['prefix'] == "bchtest" || decoded['prefix'] == "slptest";
-    var version;
+    late var version;
     if (testnet) {
       switch (decoded['type']) {
         case "P2PKH":
@@ -171,7 +173,7 @@ class Address {
   }
 
   /// Converts legacy address to cash address
-  static String toCashAddress(String address, [bool includePrefix = true]) {
+  static String? toCashAddress(String address, [bool includePrefix = true]) {
     final decoded = _decode(address);
     switch (decoded["prefix"]) {
       case 'bitcoincash':
@@ -194,8 +196,34 @@ class Address {
     }
   }
 
+  /// Converts legacy address to cash address
+  static String? toTokenAddress(String address, [bool includePrefix = true]) {
+    final decoded = _decode(address);
+    switch (decoded["prefix"]) {
+      case 'bitcoincash':
+      case 'simpleledger':
+        decoded['prefix'] = "bitcoincash";
+        break;
+      case 'bchtest':
+      case 'slptest':
+        decoded['prefix'] = "bchtest";
+        break;
+      default:
+        throw FormatException("Unsupported address format: $address");
+    }
+
+    final tokenAddress =
+        _encode(decoded['prefix'], "P2PKHWITHTOKENS", decoded["hash"]);
+
+    if (!includePrefix) {
+      return tokenAddress.split(":")[1];
+    } else {
+      return tokenAddress;
+    }
+  }
+
   /// Converts legacy or cash address to SLP address
-  static String toSLPAddress(String address, [bool includePrefix = true]) {
+  static String? toSLPAddress(String address, [bool includePrefix = true]) {
     final decoded = Address._decode(address);
     switch (decoded["prefix"]) {
       case 'bitcoincash':
@@ -231,7 +259,7 @@ class Address {
   }
 
   /// Detects type of the address and returns [legacy], [cashaddr] or [slpaddr]
-  static String detectAddressFormat(String address) {
+  static String? detectAddressFormat(String address) {
     // decode the address to determine the format
     final decoded = _decode(address);
     // return the format
@@ -261,7 +289,7 @@ class Address {
   /// [prefix] - Network prefix. E.g.: 'bitcoincash'.
   /// [type] Type of address to generate. Either 'P2PKH' or 'P2SH'.
   /// [hash] is the address hash, which can be decode either using [_decodeCashAddress()] or [_decodeLegacyAddress()]
-  static _encode(String prefix, String type, Uint8List hash) {
+  static _encode(String prefix, String? type, Uint8List hash) {
     final prefixData = _prefixToUint5List(prefix) + Uint8List(1);
     final versionByte = _getTypeBits(type) + _getHashSizeBits(hash);
     final payloadData =
@@ -278,7 +306,7 @@ class Address {
     assert(addresses is String || addresses is List<String>);
 
     if (addresses is String) {
-      return await RestApi.sendGetRequest("address/$path", addresses) as Map;
+      return await RestApi.sendGetRequest("address/$path", addresses) as Map?;
     } else if (addresses is List<String>) {
       return await RestApi.sendPostRequest(
           "address/$path", "addresses", addresses,
@@ -351,6 +379,8 @@ class Address {
         return 'P2PKH';
       case 8:
         return 'P2SH';
+      case 16:
+        return 'P2PKHWITHTOKENS';
       default:
         throw FormatException(
             'Invalid address type in version byte: ' + versionByte + '.');
@@ -363,6 +393,8 @@ class Address {
         return 0;
       case 'P2SH':
         return 8;
+      case 'P2PKHWITHTOKENS':
+        return 16;
       default:
         throw new FormatException('Invalid type: ' + type + '.');
     }
@@ -453,7 +485,7 @@ class Address {
       throw FormatException("Invalid Address Format: $address");
     }
 
-    String exception;
+    late String exception;
     // try to decode the address with either one or all three possible prefixes
     for (int i = 0; i < prefixes.length; i++) {
       final payload = _base32Decode(address);
@@ -514,7 +546,7 @@ class Address {
       throw FormatException("Invalid Address Format: $address");
     }
 
-    String exception;
+    late String exception;
 
     // try to decode the address with either one or all three possible prefixes
     for (int i = 0; i < prefixes.length; i++) {
@@ -642,7 +674,7 @@ class Address {
       final value = string[i];
       if (!_CHARSET_INVERSE_INDEX.containsKey(value))
         throw FormatException("Invalid character '$value'");
-      data[i] = _CHARSET_INVERSE_INDEX[string[i]];
+      data[i] = _CHARSET_INVERSE_INDEX[string[i]]!;
     }
 
     return data;
@@ -672,12 +704,12 @@ class Address {
 
 /// Container for to make it easier to work with Utxos
 class Utxo {
-  final String txid;
-  final int vout;
-  final double amount;
-  final int satoshis;
-  final int height;
-  final int confirmations;
+  final String? txid;
+  final int? vout;
+  final double? amount;
+  final int? satoshis;
+  final int? height;
+  final int? confirmations;
 
   Utxo(this.txid, this.vout, this.amount, this.satoshis, this.height,
       this.confirmations);

lib/src/bitcoincash.dart

@@ -40,7 +40,7 @@ class BitcoinCash {
     return signatureBuffer;
   }
 
-  static Uint8List getOpReturnScript(String data) {
+  static Uint8List? getOpReturnScript(String data) {
     return compile([Opcodes.OP_RETURN, utf8.encode(data)]);
   }
 }

lib/src/cashaccounts.dart

@@ -3,7 +3,7 @@ import 'utils/rest_api.dart';
 import 'package:http/http.dart' as http;
 
 class CashAccounts {
-  static Future<Map> lookup(String account, int number, {int collision}) async {
+  static Future<Map?> lookup(String account, int number, {int? collision}) async {
     String col = "";
     if (collision != null) {
       col = collision.toString();
@@ -13,19 +13,19 @@ class CashAccounts {
     return json.decode(response.body);
   }
 
-  static Future<Map> check(String account, int number) async {
+  static Future<Map?> check(String account, int number) async {
     final response = await http.get(Uri.parse(
         "https://rest.bitcoin.com/v2/cashAccounts/check/$account/$number"));
     return json.decode(response.body);
   }
 
-  static Future<Map> reverseLookup(String cashAddress) async {
+  static Future<Map?> reverseLookup(String cashAddress) async {
     final response = await http.get(Uri.parse(
         "https://rest.bitcoin.com/v2/cashAccounts/reverseLookup/$cashAddress"));
     return json.decode(response.body);
   }
 
-  static Future<Map> register(String name, String address) async {
+  static Future<Map?> register(String name, String address) async {
     Map register = {
       'name': name,
       'payments': [address]
@@ -34,7 +34,7 @@ class CashAccounts {
         Uri.parse('https://api.cashaccount.info/register'),
         headers: {'Content-Type': 'application/json'},
         body: jsonEncode(register));
-    Map data = jsonDecode(response.body);
+    Map? data = jsonDecode(response.body);
     return data;
   }
 }

lib/src/crypto/ecies.dart

@@ -34,9 +34,9 @@ class Ecies {
   /// [recipientPublicKey] - Public Key of the party who can decrypt the message
   ///
   static String encryptData(
-      {String message,
-      String senderPrivateKeyHex,
-      String recipientPublicKeyHex,
+      {required String message,
+      required String senderPrivateKeyHex,
+      required String recipientPublicKeyHex,
       String magicValue = "BIE1"}) {
     //Encryption requires derivation of a cipher using the other party's Public Key
     // Bob is sender, Alice is recipient of encrypted message
@@ -51,10 +51,10 @@ class Ecies {
 
     List<int> messageBuffer = Uint8List.fromList(message.codeUnits);
 
-    final ECPoint S = (recipientPublicKey.point *
-        senderPrivateKey.privateKey); //point multiplication
+    final ECPoint S = (recipientPublicKey.point! *
+        senderPrivateKey.privateKey)!; //point multiplication
 
-    final pubkeyS = BCHPublicKey.fromXY(S.x.toBigInteger(), S.y.toBigInteger());
+    final pubkeyS = BCHPublicKey.fromXY(S.x!.toBigInteger()!, S.y!.toBigInteger()!);
     final pubkeyBuffer = HEX.decode(pubkeyS.getEncoded(true));
     final pubkeyHash = SHA512Digest().process(pubkeyBuffer as Uint8List);
 
@@ -73,7 +73,7 @@ class Ecies {
     final magic = utf8.encode(magicValue);
 
     final encodedBuffer = Uint8List.fromList(
-        magic + HEX.decode(senderPrivateKey.publicKey.toHex()) + cipherText);
+        magic + HEX.decode(senderPrivateKey.publicKey!.toHex()) + cipherText);
 
     //calc checksum
     final hmac = _calculateHmac(kM, encodedBuffer);
@@ -101,8 +101,8 @@ class Ecies {
   /// [recipientPrivateKey] - Private Key of the receiving party
   ///
   static String decryptData(
-      {String cipherTextStr,
-      String recipientPrivateKeyHex,
+      {required String cipherTextStr,
+      required String recipientPrivateKeyHex,
       String magicValue = "BIE1"}) {
     //AES Cipher is calculated as
     //1) S = recipientPrivateKey o senderPublicKey
@@ -128,8 +128,8 @@ class Ecies {
         BCHPublicKey.fromHex(HEX.encode(senderPubkeyBuffer));
 
     //calculate S = recipientPrivateKey o senderPublicKey
-    final S = (senderPublicKey.point *
-        recipientPrivateKey.privateKey); //point multiplication
+    final S = (senderPublicKey.point! *
+        recipientPrivateKey.privateKey)!; //point multiplication
     final cipher = S.x;
 
     if (cipherText.length - _tagLength <= 37) {
@@ -138,7 +138,7 @@ class Ecies {
     }
 
     //validate the checksum bytes
-    final pubkeyS = BCHPublicKey.fromXY(S.x.toBigInteger(), S.y.toBigInteger());
+    final pubkeyS = BCHPublicKey.fromXY(S.x!.toBigInteger()!, S.y!.toBigInteger()!);
     final pubkeyBuffer = HEX.decode(pubkeyS.getEncoded(true));
     final pubkeyHash = SHA512Digest().process(pubkeyBuffer as Uint8List);
 
@@ -153,7 +153,7 @@ class Ecies {
     final Uint8List hmac = _calculateHmac(kM, message);
 
     final Uint8List messageChecksum =
-        cipherText.sublist(cipherText.length - _tagLength, cipherText.length);
+        cipherText.sublist(cipherText.length - _tagLength, cipherText.length) as Uint8List;
 
     // ignore: prefer_const_constructors
     if (!ListEquality().equals(messageChecksum, hmac)) {