139 lines
4.3 KiB
Python
139 lines
4.3 KiB
Python
# BlockStore: a helper class that keeps a map of blocks and implements
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# helper functions for responding to getheaders and getdata,
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# and for constructing a getheaders message
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#
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from mininode import *
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import dbm
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class BlockStore(object):
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def __init__(self, datadir):
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self.blockDB = dbm.open(datadir + "/blocks", 'c')
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self.currentBlock = 0L
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self.headers_map = dict()
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def close(self):
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self.blockDB.close()
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def get(self, blockhash):
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serialized_block = None
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try:
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serialized_block = self.blockDB[repr(blockhash)]
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except KeyError:
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return None
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f = cStringIO.StringIO(serialized_block)
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ret = CBlock()
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ret.deserialize(f)
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ret.calc_sha256()
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return ret
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def get_header(self, blockhash):
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try:
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return self.headers_map[blockhash]
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except KeyError:
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return None
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# Note: this pulls full blocks out of the database just to retrieve
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# the headers -- perhaps we could keep a separate data structure
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# to avoid this overhead.
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def headers_for(self, locator, hash_stop, current_tip=None):
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if current_tip is None:
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current_tip = self.currentBlock
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current_block_header = self.get_header(current_tip)
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if current_block_header is None:
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return None
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response = msg_headers()
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headersList = [ current_block_header ]
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maxheaders = 2000
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while (headersList[0].sha256 not in locator.vHave):
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prevBlockHash = headersList[0].hashPrevBlock
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prevBlockHeader = self.get_header(prevBlockHash)
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if prevBlockHeader is not None:
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headersList.insert(0, prevBlockHeader)
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else:
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break
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headersList = headersList[:maxheaders] # truncate if we have too many
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hashList = [x.sha256 for x in headersList]
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index = len(headersList)
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if (hash_stop in hashList):
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index = hashList.index(hash_stop)+1
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response.headers = headersList[:index]
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return response
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def add_block(self, block):
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block.calc_sha256()
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try:
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self.blockDB[repr(block.sha256)] = bytes(block.serialize())
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except TypeError as e:
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print "Unexpected error: ", sys.exc_info()[0], e.args
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self.currentBlock = block.sha256
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self.headers_map[block.sha256] = CBlockHeader(block)
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def add_header(self, header):
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self.headers_map[header.sha256] = header
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def get_blocks(self, inv):
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responses = []
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for i in inv:
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if (i.type == 2): # MSG_BLOCK
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block = self.get(i.hash)
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if block is not None:
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responses.append(msg_block(block))
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return responses
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def get_locator(self, current_tip=None):
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if current_tip is None:
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current_tip = self.currentBlock
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r = []
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counter = 0
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step = 1
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lastBlock = self.get(current_tip)
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while lastBlock is not None:
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r.append(lastBlock.hashPrevBlock)
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for i in range(step):
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lastBlock = self.get(lastBlock.hashPrevBlock)
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if lastBlock is None:
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break
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counter += 1
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if counter > 10:
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step *= 2
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locator = CBlockLocator()
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locator.vHave = r
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return locator
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class TxStore(object):
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def __init__(self, datadir):
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self.txDB = dbm.open(datadir + "/transactions", 'c')
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def close(self):
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self.txDB.close()
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def get(self, txhash):
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serialized_tx = None
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try:
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serialized_tx = self.txDB[repr(txhash)]
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except KeyError:
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return None
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f = cStringIO.StringIO(serialized_tx)
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ret = CTransaction()
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ret.deserialize(f)
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ret.calc_sha256()
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return ret
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def add_transaction(self, tx):
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tx.calc_sha256()
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try:
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self.txDB[repr(tx.sha256)] = bytes(tx.serialize())
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except TypeError as e:
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print "Unexpected error: ", sys.exc_info()[0], e.args
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def get_transactions(self, inv):
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responses = []
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for i in inv:
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if (i.type == 1): # MSG_TX
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tx = self.get(i.hash)
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if tx is not None:
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responses.append(msg_tx(tx))
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return responses
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