bound number of tx inputs in sweep

lib/commands.py

@@ -369,15 +369,15 @@ class Commands:
         return out['address']
 
     @command('nw')
-    def sweep(self, privkey, destination, tx_fee=None, nocheck=False):
+    def sweep(self, privkey, destination, tx_fee=None, nocheck=False, imax=100):
         """Sweep private keys. Returns a transaction that spends UTXOs from
         privkey to a destination address. The transaction is not
         broadcasted."""
         privkeys = privkey if type(privkey) is list else [privkey]
         self.nocheck = nocheck
         dest = self._resolver(destination)
-        tx = self.wallet.sweep(privkeys, self.network, self.config, dest, tx_fee)
-        return tx.as_dict()
+        tx = self.wallet.sweep(privkeys, self.network, self.config, dest, tx_fee, imax)
+        return tx.as_dict() if tx else None
 
     @command('wp')
     def signmessage(self, address, message):
@@ -652,6 +652,7 @@ command_options = {
     'show_balance':("-b", "--balance",     "Show the balances of listed addresses"),
     'show_labels': ("-l", "--labels",      "Show the labels of listed addresses"),
     'nocheck':     (None, "--nocheck",     "Do not verify aliases"),
+    'imax':        (None, "--imax",        "Maximum number of inputs"),
     'tx_fee':      ("-f", "--fee",         "Transaction fee (in BTC)"),
     'from_addr':   ("-F", "--from",        "Source address. If it isn't in the wallet, it will ask for the private key unless supplied in the format public_key:private_key. It's not saved in the wallet."),
     'change_addr': ("-c", "--change",      "Change address. Default is a spare address, or the source address if it's not in the wallet"),
@@ -678,6 +679,7 @@ json_loads = lambda x: json.loads(x, parse_float=lambda x: str(Decimal(x)))
 arg_types = {
     'num': int,
     'nbits': int,
+    'imax': int,
     'tx': tx_from_str,
     'pubkeys': json_loads,
     'jsontx': json_loads,

lib/wallet.py

@@ -854,7 +854,7 @@ class Abstract_Wallet(PrintError):
         self.sign_transaction(tx, password)
         return tx
 
-    def sweep(self, privkeys, network, config, recipient, fee):
+    def sweep(self, privkeys, network, config, recipient, fee=None, imax=100):
         inputs = []
         keypairs = {}
         for privkey in privkeys:
@@ -863,6 +863,8 @@ class Abstract_Wallet(PrintError):
             u = network.synchronous_get(('blockchain.address.listunspent', [address]))
             pay_script = Transaction.pay_script(TYPE_ADDRESS, address)
             for item in u:
+                if len(inputs) >= imax:
+                    break
                 item['scriptPubKey'] = pay_script
                 item['redeemPubkey'] = pubkey
                 item['address'] = address
@@ -872,7 +874,7 @@ class Abstract_Wallet(PrintError):
                 item['x_pubkeys'] = [pubkey]
                 item['signatures'] = [None]
                 item['num_sig'] = 1
-            inputs += u
+                inputs.append(item)
             keypairs[pubkey] = privkey
 
         if not inputs: