Add Decred(DCR) (#402)

.travis.yml

@@ -20,6 +20,7 @@ install:
   - pip install tribus-hash
   - pip install pytest-cov
   - pip install pylru
+  - pip install blake256
 # command to run tests
 script: pytest --cov=server --cov=lib --cov=wallet
 # Dont report coverage from nightly

lib/coins.py

@@ -35,6 +35,7 @@ import re
 import struct
 from decimal import Decimal
 from hashlib import sha256
+from functools import partial
 
 import lib.util as util
 from lib.hash import Base58, hash160, double_sha256, hash_to_str
@@ -1420,3 +1421,54 @@ class BitcoinAtom(Coin):
         '''Return the block header bytes'''
         deserializer = cls.DESERIALIZER(block)
         return deserializer.read_header(height, cls.BASIC_HEADER_SIZE)
+
+
+class Decred(Coin):
+    NAME = "Decred"
+    SHORTNAME = "DCR"
+    NET = "mainnet"
+    XPUB_VERBYTES = bytes('dpub', 'utf-8')
+    XPRV_VERBYTES = bytes('dprv', 'utf-8')
+    P2PKH_VERBYTE = bytes('Ds', 'utf-8')
+    P2SH_VERBYTES = [bytes('Dc', 'utf-8')]
+    WIF_BYTE = bytes('Pm', 'utf-8')
+    GENESIS_HASH = ('298e5cc3d985bfe7f81dc135f360abe089edd4396b86d2de66b0cef42b21d980')
+    DESERIALIZER = lib_tx.DeserializerDecred
+    ENCODE_CHECK = partial(Base58.encode_check, hash_fn=lib_tx.DeserializerDecred.blake256)
+    DECODE_CHECK = partial(Base58.decode_check, hash_fn=lib_tx.DeserializerDecred.blake256)
+    HEADER_HASH = lib_tx.DeserializerDecred.blake256
+    BASIC_HEADER_SIZE = 180
+    ALLOW_ADVANCING_ERRORS = True
+    TX_COUNT = 217380620
+    TX_COUNT_HEIGHT = 218875
+    TX_PER_BLOCK = 1000
+    RPC_PORT = 9109
+
+    @classmethod
+    def header_hash(cls, header):
+        '''Given a header return the hash.'''
+        return cls.HEADER_HASH(header)
+
+    @classmethod
+    def block(cls, raw_block, height):
+        '''Return a Block namedtuple given a raw block and its height.'''
+        if height > 0:
+            return super().block(raw_block, height)
+        else:
+            return Block(raw_block, cls.block_header(raw_block, height), [])        
+
+
+class DecredTestnet(Decred):
+    NAME = "Decred"
+    NET = "testnet"
+    XPUB_VERBYTES = bytes('tpub', 'utf-8')
+    XPRV_VERBYTES = bytes('tprv', 'utf-8')
+    P2PKH_VERBYTE = bytes('Ts', 'utf-8')
+    P2SH_VERBYTES = [bytes('Tc', 'utf-8')]
+    WIF_BYTE = bytes('Pt', 'utf-8')
+    GENESIS_HASH = ('4261602a9d07d80ad47621a64ba6a07754902e496777edc4ff581946bd7bc29c')
+    TX_COUNT = 3176305
+    TX_COUNT_HEIGHT = 254198
+    TX_PER_BLOCK = 1000
+    RPC_PORT = 19119
+    

lib/tx.py

@@ -401,3 +401,106 @@ class DeserializerBitcoinAtom(DeserializerSegWit):
         if height >= self.FORK_BLOCK_HEIGHT:
             header_len += 4 # flags
         return self._read_nbytes(header_len)
+
+
+# Decred
+class TxInputDcr(namedtuple("TxInput", "prev_hash prev_idx tree sequence")):
+    '''Class representing a Decred transaction input.'''
+
+    ZERO = bytes(32)
+    MINUS_1 = 4294967295
+
+    @cachedproperty
+    def is_coinbase(self):
+        # The previous output of a coin base must have a max value index and a
+        # zero hash.
+        return (self.prev_hash == TxInputDcr.ZERO and
+                self.prev_idx == TxInputDcr.MINUS_1)
+
+    def __str__(self):
+        prev_hash = hash_to_str(self.prev_hash)
+        return ("Input({}, {:d}, tree={}, sequence={:d})"
+                .format(prev_hash, self.prev_idx, self.tree, self.sequence))
+
+
+class TxOutputDcr(namedtuple("TxOutput", "value version pk_script")):
+    '''Class representing a transaction output.'''
+    pass
+
+
+class TxDcr(namedtuple("Tx", "version inputs outputs locktime expiry "
+                             "witness")):
+    '''Class representing transaction that has a time field.'''
+
+    @cachedproperty
+    def is_coinbase(self):
+        return self.inputs[0].is_coinbase
+
+
+class DeserializerDecred(Deserializer):
+
+    @staticmethod
+    def blake256(data):
+        from blake256.blake256 import blake_hash
+        return blake_hash(data)
+
+    def read_tx_block(self):
+        '''Returns a list of (deserialized_tx, tx_hash) pairs.'''
+        read_tx = self.read_tx
+        txs = [read_tx() for _ in range(self._read_varint())]
+        stxs = [read_tx() for _ in range(self._read_varint())]
+        return txs + stxs
+
+    def _read_inputs(self):
+        read_input = self._read_input
+        return [read_input() for i in range(self._read_varint())]
+
+    def _read_input(self):
+        return TxInputDcr(
+            self._read_nbytes(32),   # prev_hash
+            self._read_le_uint32(),  # prev_idx
+            self._read_byte(),       # tree
+            self._read_le_uint32(),  # sequence
+        )
+
+    def _read_outputs(self):
+        read_output = self._read_output
+        return [read_output() for _ in range(self._read_varint())]
+
+    def _read_output(self):
+        return TxOutputDcr(
+            self._read_le_int64(),  # value
+            self._read_le_uint16(),  # version
+            self._read_varbytes(),  # pk_script
+        )
+
+    def _read_witness(self, fields):
+        read_witness_field = self._read_witness_field
+        assert fields == self._read_varint()
+        return [read_witness_field() for _ in range(fields)]
+
+    def _read_witness_field(self):
+        value_in = self._read_le_int64()
+        block_height = self._read_le_uint32()
+        block_index = self._read_le_uint32()
+        script = self._read_varbytes()
+        return value_in, block_height, block_index, script
+
+    def read_tx(self):
+        start = self.cursor
+        version = self._read_le_int32()
+        assert version == 1 # TODO check other versions for segwit
+        inputs = self._read_inputs()
+        outputs = self._read_outputs()
+        locktime = self._read_le_uint32()
+        expiry = self._read_le_uint32()
+        no_witness_tx = b'\x01\x00\x01\x00' + self.binary[start+4:self.cursor]
+        witness = self._read_witness(len(inputs))
+        return TxDcr(
+            version,
+            inputs,
+            outputs,
+            locktime,
+            expiry,
+            witness
+        ), DeserializerDecred.blake256(no_witness_tx)        

setup.py

@@ -10,6 +10,7 @@ setuptools.setup(
     # via environment variables, in which case I've tested with 15.0.4
     # "x11_hash" package (1.4) is required to sync DASH network.
     # "tribus_hash" package is required to sync Denarius network.
+    # "blake256" package is required to sync Decred network.
     install_requires=['plyvel', 'pylru', 'aiohttp >= 1'],
     packages=setuptools.find_packages(exclude=['tests']),
     description='ElectrumX Server',

tests/blocks/decred_testnet_200000.json

@@ -0,0 +1,17 @@
+{
+  "hash": "0000000003416ee936e24e3d8ebb0ae12cc9cd397df61346f2805642676291ae",
+  "size": 1637,
+  "height": 200000,
+  "merkleroot": "560d636172de028d728723b41428eb51acb4e969caf54f50f0de19f14a66fb1e",
+  "tx": [
+    "42fb258edd91d3b4aeea43f2451311b1045e3d0f935491301e03377eb86b1c46",
+    "9b1e326156e1426d1b2c32d711e660c936f53fcdf90de3ea4f8ae18c695751e0",
+    "017ac016d59cbc1b381ae71f61173bf9b5eaf85e338f2b81df73f88574bc7fa6",
+    "a15ddc52b33346ddb22005eaf622336d0f56856f598e1068d1fba280d9cf0408"
+  ],
+  "time": 1513807068,
+  "nonce": 4094753344,
+  "bits": "1c038167",
+  "previousblockhash": "0000000001c195bb55127867a4dbeb9385fc14113db92a787ccd8c64d4bab58f",
+  "block": "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"
+}