URI: 
       tMerge pull request #1579 from fanatid/blockchain - electrum - Electrum Bitcoin wallet
  HTML git clone https://git.parazyd.org/electrum
   DIR Log
   DIR Files
   DIR Refs
   DIR Submodules
       ---
   DIR commit 822260854fee2086c0d8881bb9f228034e092e73
   DIR parent eef62112a83345d268cb7e7fd955e73c26429c5e
  HTML Author: Neil <kyuupichan@gmail.com>
       Date:   Sun, 13 Dec 2015 11:35:17 +0900
       
       Merge pull request #1579 from fanatid/blockchain
       
       Small blockchain.py changes
       Diffstat:
         M lib/blockchain.py                   |      78 ++++++++++++++++---------------
       
       1 file changed, 41 insertions(+), 37 deletions(-)
       ---
   DIR diff --git a/lib/blockchain.py b/lib/blockchain.py
       t@@ -28,7 +28,7 @@ class Blockchain(util.PrintError):
            def __init__(self, config, network):
                self.config = config
                self.network = network
       -        self.headers_url = 'https://headers.electrum.org/blockchain_headers'
       +        self.headers_url = "https://headers.electrum.org/blockchain_headers"
                self.local_height = 0
                self.set_local_height()
        
       t@@ -40,42 +40,42 @@ class Blockchain(util.PrintError):
                self.set_local_height()
                self.print_error("%d blocks" % self.local_height)
        
       -    def verify_headers(self, header, prev_header, bits, target):
       +    def verify_header(self, header, prev_header, bits, target):
                prev_hash = self.hash_header(prev_header)
       -        assert prev_hash == header.get('prev_block_hash'), "prev hash mismatch: %s vs %s"% (prev_hash, header.get('prev_block_hash'))
       +        assert prev_hash == header.get('prev_block_hash'), "prev hash mismatch: %s vs %s" % (prev_hash, header.get('prev_block_hash'))
                assert bits == header.get('bits'), "bits mismatch: %s vs %s" % (bits, header.get('bits'))
                _hash = self.hash_header(header)
       -        assert int('0x'+_hash, 16) <= target, "insufficient proof of work: %s vs target %s" % (int('0x'+_hash, 16), target)
       +        assert int('0x' + _hash, 16) <= target, "insufficient proof of work: %s vs target %s" % (int('0x' + _hash, 16), target)
        
            def verify_chain(self, chain):
                first_header = chain[0]
       -        prev_header = self.read_header(first_header.get('block_height') -1)
       +        prev_header = self.read_header(first_header.get('block_height') - 1)
                for header in chain:
                    height = header.get('block_height')
       -            bits, target = self.get_target(height/2016, chain)
       -            self.verify_headers(header, prev_header, bits, target)
       +            bits, target = self.get_target(height / 2016, chain)
       +            self.verify_header(header, prev_header, bits, target)
                    prev_header = header
        
            def verify_chunk(self, index, hexdata):
                data = hexdata.decode('hex')
       -        num = len(data)/80
       -        prev_header = None if index == 0 else self.read_header(index*2016-1)
       +        num = len(data) / 80
       +        prev_header = None
       +        if index != 0:
       +            prev_header = self.read_header(index*2016 - 1)
                bits, target = self.get_target(index)
                for i in range(num):
       -            raw_header = data[i*80:(i+1)*80]
       +            raw_header = data[i*80:(i+1) * 80]
                    header = self.deserialize_header(raw_header)
       -            self.verify_headers(header, prev_header, bits, target)
       +            self.verify_header(header, prev_header, bits, target)
                    prev_header = header
       -        self.save_chunk(index, data)
       -        self.print_error("validated chunk %d" % index)
        
            def serialize_header(self, res):
       -        s = int_to_hex(res.get('version'),4) \
       +        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)
       +            + 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 deserialize_header(self, s):
       t@@ -90,7 +90,9 @@ class Blockchain(util.PrintError):
                return h
        
            def hash_header(self, header):
       -        return "0"*64 if header is None else rev_hex(Hash(self.serialize_header(header).decode('hex')).encode('hex'))
       +        if header is None:
       +            return '0' * 64
       +        return hash_encode(Hash(self.serialize_header(header).decode('hex')))
        
            def path(self):
                return os.path.join(self.config.path, 'blockchain_headers')
       t@@ -102,17 +104,17 @@ class Blockchain(util.PrintError):
                try:
                    import urllib, socket
                    socket.setdefaulttimeout(30)
       -            self.print_error("downloading ", self.headers_url )
       +            self.print_error("downloading ", self.headers_url)
                    urllib.urlretrieve(self.headers_url, filename)
                    self.print_error("done.")
                except Exception:
       -            self.print_error( "download failed. creating file", filename )
       -            open(filename,'wb+').close()
       +            self.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)
       +        f = open(filename, 'rb+')
       +        f.seek(index * 2016 * 80)
                h = f.write(chunk)
                f.close()
                self.set_local_height()
       t@@ -122,8 +124,8 @@ class Blockchain(util.PrintError):
                assert len(data) == 80
                height = header.get('block_height')
                filename = self.path()
       -        f = open(filename,'rb+')
       -        f.seek(height*80)
       +        f = open(filename, 'rb+')
       +        f.seek(height * 80)
                h = f.write(data)
                f.close()
                self.set_local_height()
       t@@ -138,8 +140,8 @@ class Blockchain(util.PrintError):
            def read_header(self, block_height):
                name = self.path()
                if os.path.exists(name):
       -            f = open(name,'rb')
       -            f.seek(block_height*80)
       +            f = open(name, 'rb')
       +            f.seek(block_height * 80)
                    h = f.read(80)
                    f.close()
                    if len(h) == 80:
       t@@ -149,11 +151,11 @@ class Blockchain(util.PrintError):
            def get_target(self, index, chain=None):
                if index == 0:
                    return 0x1d00ffff, MAX_TARGET
       -        first = self.read_header((index-1)*2016)
       -        last = self.read_header(index*2016-1)
       +        first = self.read_header((index-1) * 2016)
       +        last = self.read_header(index*2016 - 1)
                if last is None:
                    for h in chain:
       -                if h.get('block_height') == index*2016-1:
       +                if h.get('block_height') == index*2016 - 1:
                            last = h
                assert last is not None
                # bits to target
       t@@ -162,23 +164,23 @@ class Blockchain(util.PrintError):
                assert bitsN >= 0x03 and bitsN <= 0x1d, "First part of bits should be in [0x03, 0x1d]"
                bitsBase = bits & 0xffffff
                assert bitsBase >= 0x8000 and bitsBase <= 0x7fffff, "Second part of bits should be in [0x8000, 0x7fffff]"
       -        target = bitsBase << (8*(bitsN-3))
       +        target = bitsBase << (8 * (bitsN-3))
                # new target
                nActualTimespan = last.get('timestamp') - first.get('timestamp')
       -        nTargetTimespan = 14*24*60*60
       -        nActualTimespan = max(nActualTimespan, nTargetTimespan/4)
       -        nActualTimespan = min(nActualTimespan, nTargetTimespan*4)
       -        new_target = min(MAX_TARGET, (target * nActualTimespan)/nTargetTimespan)
       +        nTargetTimespan = 14 * 24 * 60 * 60
       +        nActualTimespan = max(nActualTimespan, nTargetTimespan / 4)
       +        nActualTimespan = min(nActualTimespan, nTargetTimespan * 4)
       +        new_target = min(MAX_TARGET, (target*nActualTimespan) / nTargetTimespan)
                # convert new target to bits
                c = ("%064x" % new_target)[2:]
                while c[:2] == '00' and len(c) > 6:
                    c = c[2:]
       -        bitsN, bitsBase = len(c)/2, int('0x'+c[:6], 16)
       +        bitsN, bitsBase = len(c) / 2, int('0x' + c[:6], 16)
                if bitsBase >= 0x800000:
                    bitsN += 1
                    bitsBase >>= 8
                new_bits = bitsN << 24 | bitsBase
       -        return new_bits, bitsBase << (8*(bitsN-3))
       +        return new_bits, bitsBase << (8 * (bitsN-3))
        
            def connect_header(self, chain, header):
                '''Builds a header chain until it connects.  Returns True if it has
       t@@ -213,6 +215,8 @@ class Blockchain(util.PrintError):
            def connect_chunk(self, idx, chunk):
                try:
                    self.verify_chunk(idx, chunk)
       +            self.print_error("validated chunk %d" % index)
       +            self.save_chunk(index, data)
                    return idx + 1
                except BaseException as e:
                    self.print_error('verify_chunk failed', str(e))