separate blockchain verifier from transaction verifier

electrum

@@ -133,10 +133,14 @@ if __name__ == '__main__':
         interface.start(wait = False)
         interface.send([('server.peers.subscribe',[])])
 
-        gui = gui.ElectrumGui(config,interface)
+        blockchain = BlockchainVerifier(interface, config)
+        blockchain.start()
+
+        gui = gui.ElectrumGui(config, interface, blockchain)
         gui.main(url)
         
         interface.stop()
+        blockchain.stop()
 
         # we use daemon threads, their termination is enforced.
         # this sleep command gives them time to terminate cleanly. 

gui/gui_classic.py

@@ -42,7 +42,7 @@ except:
 from electrum.wallet import format_satoshis
 from electrum.bitcoin import Transaction, is_valid
 from electrum import mnemonic
-from electrum import util, bitcoin, commands, Interface, Wallet, WalletVerifier, WalletSynchronizer
+from electrum import util, bitcoin, commands, Interface, Wallet, TxVerifier, WalletSynchronizer
 from electrum import SimpleConfig, Wallet, WalletSynchronizer, WalletStorage
 
 
@@ -307,7 +307,7 @@ class ElectrumWindow(QMainWindow):
         self.wallet.interface.register_callback('disconnected', lambda: self.emit(QtCore.SIGNAL('update_status')))
         self.wallet.interface.register_callback('disconnecting', lambda: self.emit(QtCore.SIGNAL('update_status')))
         self.wallet.interface.register_callback('new_transaction', lambda: self.emit(QtCore.SIGNAL('transaction_signal')))
-        title = 'Electrum ' + self.wallet.electrum_version + '  -  ' #+ self.config.path
+        title = 'Electrum ' + self.wallet.electrum_version + '  -  ' + self.wallet.storage.path
         if not self.wallet.seed: title += ' [%s]' % (_('seedless'))
         self.setWindowTitle( title )
         self.update_wallet()
@@ -350,13 +350,19 @@ class ElectrumWindow(QMainWindow):
             return
 
         interface = self.wallet.interface
-        verifier = self.wallet.verifier
+        blockchain = self.wallet.verifier.blockchain
+
+        self.wallet.verifier.stop()
         self.wallet.synchronizer.stop()
         
         # create wallet 
         wallet = Wallet(storage)
         wallet.interface = interface
-        wallet.verifier = verifier
+
+        verifier = TxVerifier(interface, blockchain, storage)
+        verifier.start()
+        wallet.set_verifier(verifier)
+
         synchronizer = WalletSynchronizer(wallet)
         synchronizer.start()
 
@@ -2208,9 +2214,10 @@ class OpenFileEventFilter(QObject):
 
 class ElectrumGui:
 
-    def __init__(self, config, interface, app=None):
+    def __init__(self, config, interface, blockchain, app=None):
         self.interface = interface
         self.config = config
+        self.blockchain = blockchain
         self.windows = []
         self.efilter = OpenFileEventFilter(self.windows)
         if app is None:
@@ -2232,9 +2239,10 @@ class ElectrumGui:
 
         wallet.interface = self.interface
 
-        verifier = WalletVerifier(self.interface, storage)
+        verifier = TxVerifier(self.interface, self.blockchain, storage)
         verifier.start()
         wallet.set_verifier(verifier)
+
         synchronizer = WalletSynchronizer(wallet)
         synchronizer.start()
 

lib/__init__.py

@@ -2,7 +2,8 @@ from version import ELECTRUM_VERSION
 from util import format_satoshis, print_msg, print_json, print_error, set_verbosity
 from wallet import WalletSynchronizer, WalletStorage
 from wallet_factory import WalletFactory as Wallet
-from verifier import WalletVerifier
+from verifier import TxVerifier
+from blockchain import BlockchainVerifier
 from interface import Interface, pick_random_server, DEFAULT_SERVERS
 from simple_config import SimpleConfig
 import bitcoin

lib/blockchain.py

@@ -0,0 +1,330 @@
+#!/usr/bin/env python
+#
+# Electrum - lightweight Bitcoin client
+# Copyright (C) 2012 thomasv@ecdsa.org
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+import threading, time, Queue, os, sys, shutil
+from util import user_dir, appdata_dir, print_error
+from bitcoin import *
+
+
+class BlockchainVerifier(threading.Thread):
+    """ Simple Payment Verification """
+
+    def __init__(self, interface, config):
+        threading.Thread.__init__(self)
+        self.daemon = True
+        self.config = config
+        self.interface = interface
+        self.interface.register_channel('verifier')
+        self.lock = threading.Lock()
+        self.pending_headers = [] # headers that have not been verified
+        self.height = 0
+        self.local_height = 0
+        self.running = False
+        self.headers_url = 'http://headers.electrum.org/blockchain_headers'
+
+
+    def stop(self):
+        with self.lock: self.running = False
+        self.interface.poke('verifier')
+
+    def is_running(self):
+        with self.lock: return self.running
+
+    def run(self):
+
+        self.init_headers_file()
+        self.set_local_height()
+
+        with self.lock:
+            self.running = True
+        requested_merkle = []
+        requested_chunks = []
+        requested_headers = []
+        all_chunks = False
+        
+        # subscribe to block headers
+        self.interface.send([ ('blockchain.headers.subscribe',[])], 'verifier')
+
+        while self.is_running():
+            # request missing chunks
+            if not all_chunks and self.height and not requested_chunks:
+
+                if self.local_height + 50 < self.height:
+                    min_index = (self.local_height + 1)/2016
+                    max_index = (self.height + 1)/2016
+                    for i in range(min_index, max_index + 1):
+                        print_error( "requesting chunk", i )
+                        self.interface.send([ ('blockchain.block.get_chunk',[i])], 'verifier')
+                        requested_chunks.append(i)
+                        break
+                else:
+                    all_chunks = True
+                    print_error("downloaded all chunks")
+
+
+            # process pending headers
+            if self.pending_headers and all_chunks:
+                done = []
+                for header in self.pending_headers:
+                    if self.verify_header(header):
+                        done.append(header)
+                    else:
+                        # request previous header
+                        i = header.get('block_height') - 1
+                        if i not in requested_headers:
+                            print_error("requesting header %d"%i)
+                            self.interface.send([ ('blockchain.block.get_header',[i])], 'verifier')
+                            requested_headers.append(i)
+                        # no point continuing
+                        break
+                if done:
+                    self.interface.trigger_callback('updated')
+                    for header in done: 
+                        self.pending_headers.remove(header)
+
+            try:
+                r = self.interface.get_response('verifier',timeout=1)
+            except Queue.Empty:
+                continue
+            if not r: continue
+
+            if r.get('error'):
+                print_error('Verifier received an error:', r)
+                continue
+
+            # 3. handle response
+            method = r['method']
+            params = r['params']
+            result = r['result']
+
+            if method == 'blockchain.block.get_chunk':
+                index = params[0]
+                self.verify_chunk(index, result)
+                requested_chunks.remove(index)
+
+            elif method in ['blockchain.headers.subscribe', 'blockchain.block.get_header']:
+
+                self.pending_headers.append(result)
+                if method == 'blockchain.block.get_header':
+                    requested_headers.remove(result.get('block_height'))
+                else:
+                    self.height = result.get('block_height')
+                    self.interface.poke('synchronizer')
+                
+                self.pending_headers.sort(key=lambda x: x.get('block_height'))
+                # print "pending headers", map(lambda x: x.get('block_height'), self.pending_headers)
+
+
+
+
+
+    def verify_chunk(self, index, hexdata):
+        data = hexdata.decode('hex')
+        height = index*2016
+        num = len(data)/80
+        print_error("validating headers %d"%height)
+
+        if index == 0:  
+            previous_hash = ("0"*64)
+        else:
+            prev_header = self.read_header(index*2016-1)
+            if prev_header is None: raise
+            previous_hash = self.hash_header(prev_header)
+
+        bits, target = self.get_target(index)
+
+        for i in range(num):
+            height = index*2016 + i
+            raw_header = data[i*80:(i+1)*80]
+            header = self.header_from_string(raw_header)
+            _hash = self.hash_header(header)
+            assert previous_hash == header.get('prev_block_hash')
+            assert bits == header.get('bits')
+            assert eval('0x'+_hash) < target
+
+            previous_header = header
+            previous_hash = _hash 
+
+        self.save_chunk(index, data)
+
+
+    def verify_header(self, header):
+        # add header to the blockchain file
+        # if there is a reorg, push it in a stack
+
+        height = header.get('block_height')
+
+        prev_header = self.read_header(height -1)
+        if not prev_header:
+            # return False to request previous header
+            return False
+
+        prev_hash = self.hash_header(prev_header)
+        bits, target = self.get_target(height/2016)
+        _hash = self.hash_header(header)
+        try:
+            assert prev_hash == header.get('prev_block_hash')
+            assert bits == header.get('bits')
+            assert eval('0x'+_hash) < target
+        except:
+            # this can be caused by a reorg.
+            print_error("verify header failed"+ repr(header))
+            # undo verifications
+            with self.lock:
+                items = self.verified_tx.items()[:]
+            for tx_hash, item in items:
+                tx_height, timestamp, pos = item
+                if tx_height >= height:
+                    print_error("redoing", tx_hash)
+                    with self.lock:
+                        self.verified_tx.pop(tx_hash)
+                        if tx_hash in self.merkle_roots:
+                            self.merkle_roots.pop(tx_hash)
+            # return False to request previous header.
+            return False
+
+        self.save_header(header)
+        print_error("verify header:", _hash, height)
+        return True
+        
+
+            
+
+    def header_to_string(self, res):
+        s = int_to_hex(res.get('version'),4) \
+            + rev_hex(res.get('prev_block_hash')) \
+            + rev_hex(res.get('merkle_root')) \
+            + int_to_hex(int(res.get('timestamp')),4) \
+            + int_to_hex(int(res.get('bits')),4) \
+            + int_to_hex(int(res.get('nonce')),4)
+        return s
+
+
+    def header_from_string(self, s):
+        hex_to_int = lambda s: eval('0x' + s[::-1].encode('hex'))
+        h = {}
+        h['version'] = hex_to_int(s[0:4])
+        h['prev_block_hash'] = hash_encode(s[4:36])
+        h['merkle_root'] = hash_encode(s[36:68])
+        h['timestamp'] = hex_to_int(s[68:72])
+        h['bits'] = hex_to_int(s[72:76])
+        h['nonce'] = hex_to_int(s[76:80])
+        return h
+
+    def hash_header(self, header):
+        return rev_hex(Hash(self.header_to_string(header).decode('hex')).encode('hex'))
+
+    def path(self):
+        wdir = self.config.get('blockchain_headers_path', user_dir())
+        if wdir and not os.path.exists( wdir ): os.mkdir(wdir)
+        return os.path.join( wdir, 'blockchain_headers')
+
+    def init_headers_file(self):
+        filename = self.path()
+        if os.path.exists(filename):
+            return
+        
+        try:
+            import urllib, socket
+            socket.setdefaulttimeout(30)
+            print_error("downloading ", self.headers_url )
+            urllib.urlretrieve(self.headers_url, filename)
+        except:
+            print_error( "download failed. creating file", filename )
+            open(filename,'wb+').close()
+
+    def save_chunk(self, index, chunk):
+        filename = self.path()
+        f = open(filename,'rb+')
+        f.seek(index*2016*80)
+        h = f.write(chunk)
+        f.close()
+        self.set_local_height()
+
+    def save_header(self, header):
+        data = self.header_to_string(header).decode('hex')
+        assert len(data) == 80
+        height = header.get('block_height')
+        filename = self.path()
+        f = open(filename,'rb+')
+        f.seek(height*80)
+        h = f.write(data)
+        f.close()
+        self.set_local_height()
+
+
+    def set_local_height(self):
+        name = self.path()
+        if os.path.exists(name):
+            h = os.path.getsize(name)/80 - 1
+            if self.local_height != h:
+                self.local_height = h
+
+
+    def read_header(self, block_height):
+        name = self.path()
+        if os.path.exists(name):
+            f = open(name,'rb')
+            f.seek(block_height*80)
+            h = f.read(80)
+            f.close()
+            if len(h) == 80:
+                h = self.header_from_string(h)
+                return h 
+
+
+    def get_target(self, index):
+
+        max_target = 0x00000000FFFF0000000000000000000000000000000000000000000000000000
+        if index == 0: return 0x1d00ffff, max_target
+
+        first = self.read_header((index-1)*2016)
+        last = self.read_header(index*2016-1)
+        
+        nActualTimespan = last.get('timestamp') - first.get('timestamp')
+        nTargetTimespan = 14*24*60*60
+        nActualTimespan = max(nActualTimespan, nTargetTimespan/4)
+        nActualTimespan = min(nActualTimespan, nTargetTimespan*4)
+
+        bits = last.get('bits') 
+        # convert to bignum
+        MM = 256*256*256
+        a = bits%MM
+        if a < 0x8000:
+            a *= 256
+        target = (a) * pow(2, 8 * (bits/MM - 3))
+
+        # new target
+        new_target = min( max_target, (target * nActualTimespan)/nTargetTimespan )
+        
+        # convert it to bits
+        c = ("%064X"%new_target)[2:]
+        i = 31
+        while c[0:2]=="00":
+            c = c[2:]
+            i -= 1
+
+        c = eval('0x'+c[0:6])
+        if c > 0x800000: 
+            c /= 256
+            i += 1
+
+        new_bits = c + MM * i
+        return new_bits, new_target
+

lib/verifier.py

@@ -24,34 +24,29 @@ from bitcoin import *
 
 
 
-class WalletVerifier(threading.Thread):
+class TxVerifier(threading.Thread):
     """ Simple Payment Verification """
 
-    def __init__(self, interface, config):
+    def __init__(self, interface, blockchain, storage):
         threading.Thread.__init__(self)
         self.daemon = True
-        self.config = config
+        self.storage = storage
+        self.blockchain = blockchain
         self.interface = interface
         self.transactions    = {}                                 # requested verifications (with height sent by the requestor)
-        self.interface.register_channel('verifier')
+        self.interface.register_channel('txverifier')
-
+        self.verified_tx     = storage.get('verified_tx3',{})      # height, timestamp of verified transactions
-        self.verified_tx     = config.get('verified_tx3',{})      # height, timestamp of verified transactions
+        self.merkle_roots    = storage.get('merkle_roots',{})      # hashed by me
-        self.merkle_roots    = config.get('merkle_roots',{})      # hashed by me
-        
-        self.targets         = config.get('targets',{})           # compute targets
         self.lock = threading.Lock()
-        self.pending_headers = [] # headers that have not been verified
-        self.height = 0
-        self.local_height = 0
         self.running = False
-        self.headers_url = 'http://headers.electrum.org/blockchain_headers'
+
 
     def get_confirmations(self, tx):
         """ return the number of confirmations of a monitored transaction. """
         with self.lock:
             if tx in self.verified_tx:
                 height, timestamp, pos = self.verified_tx[tx]
-                conf = (self.local_height - height + 1)
+                conf = (self.blockchain.local_height - height + 1)
                 if conf <= 0: timestamp = None
 
             elif tx in self.transactions:
@@ -102,66 +97,18 @@ class WalletVerifier(threading.Thread):
 
     def run(self):
 
-        self.init_headers_file()
-        self.set_local_height()
-
-        with self.lock:
-            self.running = True
-        requested_merkle = []
-        requested_chunks = []
-        requested_headers = []
-        all_chunks = False
-        
-        # subscribe to block headers
-        self.interface.send([ ('blockchain.headers.subscribe',[])], 'verifier')
-
         while self.is_running():
-            # request missing chunks
-            if not all_chunks and self.height and not requested_chunks:
-
-                if self.local_height + 50 < self.height:
-                    min_index = (self.local_height + 1)/2016
-                    max_index = (self.height + 1)/2016
-                    for i in range(min_index, max_index + 1):
-                        print_error( "requesting chunk", i )
-                        self.interface.send([ ('blockchain.block.get_chunk',[i])], 'verifier')
-                        requested_chunks.append(i)
-                        break
-                else:
-                    all_chunks = True
-                    print_error("downloaded all chunks")
-
             # request missing tx
             if all_chunks:
                 for tx_hash, tx_height in self.transactions.items():
                     if tx_hash not in self.verified_tx:
                         if self.merkle_roots.get(tx_hash) is None and tx_hash not in requested_merkle:
                             print_error('requesting merkle', tx_hash)
-                            self.interface.send([ ('blockchain.transaction.get_merkle',[tx_hash, tx_height]) ], 'verifier')
+                            self.interface.send([ ('blockchain.transaction.get_merkle',[tx_hash, tx_height]) ], 'txverifier')
                             requested_merkle.append(tx_hash)
 
-            # process pending headers
-            if self.pending_headers and all_chunks:
-                done = []
-                for header in self.pending_headers:
-                    if self.verify_header(header):
-                        done.append(header)
-                    else:
-                        # request previous header
-                        i = header.get('block_height') - 1
-                        if i not in requested_headers:
-                            print_error("requesting header %d"%i)
-                            self.interface.send([ ('blockchain.block.get_header',[i])], 'verifier')
-                            requested_headers.append(i)
-                        # no point continuing
-                        break
-                if done:
-                    self.interface.trigger_callback('updated')
-                    for header in done: 
-                        self.pending_headers.remove(header)
-
             try:
-                r = self.interface.get_response('verifier',timeout=1)
+                r = self.interface.get_response('txverifier',timeout=1)
             except Queue.Empty:
                 continue
             if not r: continue
@@ -180,30 +127,12 @@ class WalletVerifier(threading.Thread):
                 self.verify_merkle(tx_hash, result)
                 requested_merkle.remove(tx_hash)
 
-            elif method == 'blockchain.block.get_chunk':
-                index = params[0]
-                self.verify_chunk(index, result)
-                requested_chunks.remove(index)
-
-            elif method in ['blockchain.headers.subscribe', 'blockchain.block.get_header']:
-
-                self.pending_headers.append(result)
-                if method == 'blockchain.block.get_header':
-                    requested_headers.remove(result.get('block_height'))
-                else:
-                    self.height = result.get('block_height')
-                    self.interface.poke('synchronizer')
-                
-                self.pending_headers.sort(key=lambda x: x.get('block_height'))
-                # print "pending headers", map(lambda x: x.get('block_height'), self.pending_headers)
-
-
 
     def verify_merkle(self, tx_hash, result):
         tx_height = result.get('block_height')
         pos = result.get('pos')
         self.merkle_roots[tx_hash] = self.hash_merkle_root(result['merkle'], tx_hash, pos)
-        header = self.read_header(tx_height)
+        header = self.blockchain.read_header(tx_height)
         if not header: return
         assert header.get('merkle_root') == self.merkle_roots[tx_hash]
         # we passed all the tests
@@ -212,106 +141,10 @@ class WalletVerifier(threading.Thread):
         with self.lock:
             self.verified_tx[tx_hash] = (tx_height, timestamp, pos)
         print_error("verified %s"%tx_hash)
-        self.config.set_key('verified_tx3', self.verified_tx, True)
+        self.storage.set_key('verified_tx3', self.verified_tx, True)
         self.interface.trigger_callback('updated')
 
 
-    def verify_chunk(self, index, hexdata):
-        data = hexdata.decode('hex')
-        height = index*2016
-        num = len(data)/80
-        print_error("validating headers %d"%height)
-
-        if index == 0:  
-            previous_hash = ("0"*64)
-        else:
-            prev_header = self.read_header(index*2016-1)
-            if prev_header is None: raise
-            previous_hash = self.hash_header(prev_header)
-
-        bits, target = self.get_target(index)
-
-        for i in range(num):
-            height = index*2016 + i
-            raw_header = data[i*80:(i+1)*80]
-            header = self.header_from_string(raw_header)
-            _hash = self.hash_header(header)
-            assert previous_hash == header.get('prev_block_hash')
-            assert bits == header.get('bits')
-            assert eval('0x'+_hash) < target
-
-            previous_header = header
-            previous_hash = _hash 
-
-        self.save_chunk(index, data)
-
-
-    def verify_header(self, header):
-        # add header to the blockchain file
-        # if there is a reorg, push it in a stack
-
-        height = header.get('block_height')
-
-        prev_header = self.read_header(height -1)
-        if not prev_header:
-            # return False to request previous header
-            return False
-
-        prev_hash = self.hash_header(prev_header)
-        bits, target = self.get_target(height/2016)
-        _hash = self.hash_header(header)
-        try:
-            assert prev_hash == header.get('prev_block_hash')
-            assert bits == header.get('bits')
-            assert eval('0x'+_hash) < target
-        except:
-            # this can be caused by a reorg.
-            print_error("verify header failed"+ repr(header))
-            # undo verifications
-            with self.lock:
-                items = self.verified_tx.items()[:]
-            for tx_hash, item in items:
-                tx_height, timestamp, pos = item
-                if tx_height >= height:
-                    print_error("redoing", tx_hash)
-                    with self.lock:
-                        self.verified_tx.pop(tx_hash)
-                        if tx_hash in self.merkle_roots:
-                            self.merkle_roots.pop(tx_hash)
-            # return False to request previous header.
-            return False
-
-        self.save_header(header)
-        print_error("verify header:", _hash, height)
-        return True
-        
-
-            
-
-    def header_to_string(self, res):
-        s = int_to_hex(res.get('version'),4) \
-            + rev_hex(res.get('prev_block_hash')) \
-            + rev_hex(res.get('merkle_root')) \
-            + int_to_hex(int(res.get('timestamp')),4) \
-            + int_to_hex(int(res.get('bits')),4) \
-            + int_to_hex(int(res.get('nonce')),4)
-        return s
-
-
-    def header_from_string(self, s):
-        hex_to_int = lambda s: eval('0x' + s[::-1].encode('hex'))
-        h = {}
-        h['version'] = hex_to_int(s[0:4])
-        h['prev_block_hash'] = hash_encode(s[4:36])
-        h['merkle_root'] = hash_encode(s[36:68])
-        h['timestamp'] = hex_to_int(s[68:72])
-        h['bits'] = hex_to_int(s[72:76])
-        h['nonce'] = hex_to_int(s[76:80])
-        return h
-
-    def hash_header(self, header):
-        return rev_hex(Hash(self.header_to_string(header).decode('hex')).encode('hex'))
-
     def hash_merkle_root(self, merkle_s, target_hash, pos):
         h = hash_decode(target_hash)
         for i in range(len(merkle_s)):
@@ -319,101 +152,6 @@ class WalletVerifier(threading.Thread):
             h = Hash( hash_decode(item) + h ) if ((pos >> i) & 1) else Hash( h + hash_decode(item) )
         return hash_encode(h)
 
-    def path(self):
-        wdir = self.config.get('blockchain_headers_path', user_dir())
-        if wdir and not os.path.exists( wdir ): os.mkdir(wdir)
-        return os.path.join( wdir, 'blockchain_headers')
-
-    def init_headers_file(self):
-        filename = self.path()
-        if os.path.exists(filename):
-            return
-        
-        try:
-            import urllib, socket
-            socket.setdefaulttimeout(30)
-            print_error("downloading ", self.headers_url )
-            urllib.urlretrieve(self.headers_url, filename)
-        except:
-            print_error( "download failed. creating file", filename )
-            open(filename,'wb+').close()
-
-    def save_chunk(self, index, chunk):
-        filename = self.path()
-        f = open(filename,'rb+')
-        f.seek(index*2016*80)
-        h = f.write(chunk)
-        f.close()
-        self.set_local_height()
-
-    def save_header(self, header):
-        data = self.header_to_string(header).decode('hex')
-        assert len(data) == 80
-        height = header.get('block_height')
-        filename = self.path()
-        f = open(filename,'rb+')
-        f.seek(height*80)
-        h = f.write(data)
-        f.close()
-        self.set_local_height()
 
 
-    def set_local_height(self):
-        name = self.path()
-        if os.path.exists(name):
-            h = os.path.getsize(name)/80 - 1
-            if self.local_height != h:
-                self.local_height = h
-
-
-    def read_header(self, block_height):
-        name = self.path()
-        if os.path.exists(name):
-            f = open(name,'rb')
-            f.seek(block_height*80)
-            h = f.read(80)
-            f.close()
-            if len(h) == 80:
-                h = self.header_from_string(h)
-                return h 
-
-
-    def get_target(self, index):
-
-        max_target = 0x00000000FFFF0000000000000000000000000000000000000000000000000000
-        if index == 0: return 0x1d00ffff, max_target
-
-        first = self.read_header((index-1)*2016)
-        last = self.read_header(index*2016-1)
-        
-        nActualTimespan = last.get('timestamp') - first.get('timestamp')
-        nTargetTimespan = 14*24*60*60
-        nActualTimespan = max(nActualTimespan, nTargetTimespan/4)
-        nActualTimespan = min(nActualTimespan, nTargetTimespan*4)
-
-        bits = last.get('bits') 
-        # convert to bignum
-        MM = 256*256*256
-        a = bits%MM
-        if a < 0x8000:
-            a *= 256
-        target = (a) * pow(2, 8 * (bits/MM - 3))
-
-        # new target
-        new_target = min( max_target, (target * nActualTimespan)/nTargetTimespan )
-        
-        # convert it to bits
-        c = ("%064X"%new_target)[2:]
-        i = 31
-        while c[0:2]=="00":
-            c = c[2:]
-            i -= 1
-
-        c = eval('0x'+c[0:6])
-        if c > 0x800000: 
-            c /= 256
-            i += 1
-
-        new_bits = c + MM * i
-        return new_bits, new_target
 

setup.py

@@ -58,6 +58,7 @@ setup(name = "Electrum",
                   'electrum.wallet_bitkey',
                   'electrum.wallet_factory',
                   'electrum.interface',
+                  'electrum.blockchain',
                   'electrum.commands',
                   'electrum.mnemonic',
                   'electrum.simple_config',