coins: Add PIVX

No CSV or segwit.
sethdseed requires a fully synced chain, manual intervention required to set a key derived from the master mnemonic.
Requires a pivxd version with a backported scantxoutset command.

basicswap/interface/pivx.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright (c) 2020 tecnovert
+# Distributed under the MIT software license, see the accompanying
+# file LICENSE or http://www.opensource.org/licenses/mit-license.php.
+
+from .btc import BTCInterface
+from basicswap.chainparams import Coins
+from .contrib.pivx_test_framework.messages import (
+    CBlock,
+    ToHex,
+    FromHex)
+
+
+class PIVXInterface(BTCInterface):
+    @staticmethod
+    def coin_type():
+        return Coins.PIVX
+
+    def createRawSignedTransaction(self, addr_to, amount):
+        txn = self.rpc_callback('createrawtransaction', [[], {addr_to: self.format_amount(amount)}])
+
+        fee_rate, fee_src = self.get_fee_rate(self._conf_target)
+        self._log.debug(f'Fee rate: {fee_rate}, source: {fee_src}, block target: {self._conf_target}')
+
+        options = {
+            'lockUnspents': True,
+            'feeRate': fee_rate,
+        }
+        txn_funded = self.rpc_callback('fundrawtransaction', [txn, options])['hex']
+        txn_signed = self.rpc_callback('signrawtransaction', [txn_funded])['hex']
+        return txn_signed
+
+    def getBlockWithTxns(self, block_hash):
+        # TODO: Bypass decoderawtransaction and getblockheader
+        block = self.rpc_callback('getblock', [block_hash, False])
+        block_header = self.rpc_callback('getblockheader', [block_hash])
+        decoded_block = CBlock()
+        decoded_block = FromHex(decoded_block, block)
+
+        tx_rv = []
+        for tx in decoded_block.vtx:
+            tx_dec = self.rpc_callback('decoderawtransaction', [ToHex(tx)])
+            tx_rv.append(tx_dec)
+
+        block_rv = {
+            'hash': block_hash,
+            'tx': tx_rv,
+            'confirmations': block_header['confirmations'],
+            'height': block_header['height'],
+            'version': block_header['version'],
+            'merkleroot': block_header['merkleroot'],
+        }
+
+        return block_rv