Class P2PDataStore

test/functional/test_framework/p2p.py:642–765

A P2P data store class. Keeps a block and transaction store and responds correctly to getdata and getheaders requests.

class P2PDataStore(P2PInterface):
    """A P2P data store class.

    Keeps a block and transaction store and responds correctly to getdata and getheaders requests."""

    def __init__(self):
        super().__init__()
        # store of blocks. key is block hash, value is a CBlock object
        self.block_store = {}
        self.last_block_hash = ''
        # store of txs. key is txid, value is a CTransaction object
        self.tx_store = {}
        self.getdata_requests = []

    def on_getdata(self, message):
        """Check for the tx/block in our stores and if found, reply with an inv message."""
        for inv in message.inv:
            self.getdata_requests.append(inv.hash)
            if (inv.type & MSG_TYPE_MASK) == MSG_TX and inv.hash in self.tx_store.keys():
                self.send_message(msg_tx(self.tx_store[inv.hash]))
            elif (inv.type & MSG_TYPE_MASK) == MSG_BLOCK and inv.hash in self.block_store.keys():
                self.send_message(msg_block(self.block_store[inv.hash]))
            else:
                logger.debug('getdata message type {} received.'.format(hex(inv.type)))

    def on_getheaders(self, message):
        """Search back through our block store for the locator, and reply with a headers message if found."""

        locator, hash_stop = message.locator, message.hashstop

        # Assume that the most recent block added is the tip
        if not self.block_store:
            return

        headers_list = [self.block_store[self.last_block_hash]]
        while headers_list[-1].sha256 not in locator.vHave:
            # Walk back through the block store, adding headers to headers_list
            # as we go.
            prev_block_hash = headers_list[-1].hashPrevBlock
            if prev_block_hash in self.block_store:
                prev_block_header = CBlockHeader(self.block_store[prev_block_hash])
                headers_list.append(prev_block_header)
                if prev_block_header.sha256 == hash_stop:
                    # if this is the hashstop header, stop here
                    break
            else:
                logger.debug('block hash {} not found in block store'.format(hex(prev_block_hash)))
                break

        # Truncate the list if there are too many headers
        headers_list = headers_list[:-MAX_HEADERS_RESULTS - 1:-1]
        response = msg_headers(headers_list)

        if response is not None:
            self.send_message(response)

    def send_blocks_and_test(self, blocks, node, *, success=True, force_send=False, reject_reason=None, expect_disconnect=False, timeout=60):
        """Send blocks to test node and test whether the tip advances.