gistfile1.py

tx_queue = [genesis_tx]
for cur_block_height in xrange(genesis_height, max_height):
    # remove txs from this block from the queue
    block_tx_queue = [tx for tx in tx_queue if tx.block_height == cur_block_height]
    tx_queue = [tx for tx in tx_queue if tx.block_height != cur_block_height]
    
    block_txs = {}
    while block_tx_queue:
        tx = block_tx_queue.pop()
        block_txs[tx.txhash] = tx
        spends = get_spends(tx)
        for stx in spends:
            if stx.block_height == cur_block_height:
                block_tx_queue.append(stx)
            else:
                tx_queue.append(stx)

    def dependent(tx):
        """all transactions from current block this transaction directly depends on"""
        dep_tx = []
        for inp in tx.inputs:
            if inp.outpoint.hash in block_txs:
                dep_tx.append(block_txs[inp.outpoint.hash])
        return dep_tx

    sorted_block_txs = toposorted(block_txs.values(), dependent)
    
    for tx in sorted_block_txs:
        scan_tx(tx)