listunspent methods consider mempool receipts

- Update docs.  Height is 0 for mempool receipts
- Implement mempool.get_utxos() and use it
- Rename mempool.spends to mempool.potential_spends

Closes #365

docs/PROTOCOL.rst

@@ -272,14 +272,17 @@ Return an ordered list of UTXOs sent to a bitcoin address.
 **Response**
 
     A list of unspent outputs in blockchain order.  Each transaction
-    is a dictionary with keys *height* , *tx_pos*, *tx_height* and
+    is a dictionary with keys *height* , *tx_pos*, *tx_hash* and
     *value* keys.  *height* is the integer height of the block the
-    transaction was confirmed in; if unconfirmed then *height* is 0 if
-    all inputs are confirmed, and -1 otherwise.  *tx_hash* the
-    transaction hash in hexadecimal, *tx_pos* the zero-based index of
-    the output in the transaction's list of outputs, and *value* its
-    integer value in minimum coin units (satoshis in the case of
-    Bitcoin).
+    transaction was confirmed in,  *tx_hash* the transaction hash in
+    hexadecimal, *tx_pos* the zero-based index of the output in the
+    transaction's list of outputs, and *value* its integer value in
+    minimum coin units (satoshis in the case of Bitcoin).
+
+    This function takes the mempool into account.  Mempool
+    transactions paying to the address are included at the end of the
+    list in an undefined order, each with *tx_height* of zero.  Any
+    output that is spent in the mempool does not appear.
 
 **Response Example**
 

server/controller.py

@@ -788,15 +788,16 @@ class Controller(ServerBase):
         return await self.unconfirmed_history(hashX)
 
     async def hashX_listunspent(self, hashX):
-        '''Return the list of UTXOs of a script hash.
-
-        We should remove mempool spends from the in-DB UTXOs.'''
+        '''Return the list of UTXOs of a script hash, including mempool
+        effects.'''
         utxos = await self.get_utxos(hashX)
-        spends = await self.mempool.spends(hashX)
+        utxos = sorted(utxos)
+        utxos.extend(self.mempool.get_utxos(hashX))
+        spends = await self.mempool.potential_spends(hashX)
 
         return [{'tx_hash': hash_to_str(utxo.tx_hash), 'tx_pos': utxo.tx_pos,
                  'height': utxo.height, 'value': utxo.value}
-                for utxo in sorted(utxos)
+                for utxo in utxos
                 if (utxo.tx_hash, utxo.tx_pos) not in spends]
 
     async def address_listunspent(self, address):

server/mempool.py

@@ -305,14 +305,33 @@ class MemPool(util.LoggedClass):
             item = self.txs.get(hex_hash)
             if not item or not raw_tx:
                 continue
-            txin_pairs, txout_pairs, tx_fee, tx_size = item
+            tx_fee = item[2]
             tx = deserializer(raw_tx).read_tx()
             unconfirmed = any(hash_to_str(txin.prev_hash) in self.txs
                               for txin in tx.inputs)
             result.append((hex_hash, tx_fee, unconfirmed))
         return result
 
-    async def spends(self, hashX):
+    def get_utxos(self, hashX):
+        '''Return an unordered list of UTXO named tuples from mempool
+        transactions that pay to hashX.
+
+        This does not consider if any other mempool transactions spend
+        the outputs.
+        '''
+        utxos = []
+        # hashXs is a defaultdict, so use get() to query
+        for hex_hash in self.hashXs.get(hashX, []):
+            item = self.txs.get(hex_hash)
+            if not item:
+                continue
+            txout_pairs = item[1]
+            for pos, (hX, value) in enumerate(txout_pairs):
+                if hX == hashX:
+                    utxos.append(UTXO(-1, pos, hex_hash, 0, value))
+        return utxos
+
+    async def potential_spends(self, hashX):
         '''Return a set of (prev_hash, prev_idx) pairs from mempool
         transactions that touch hashX.
 
@@ -320,14 +339,14 @@ class MemPool(util.LoggedClass):
         '''
         deserializer = self.coin.DESERIALIZER
         pairs = await self.raw_transactions(hashX)
-        spends = set()
+        result = set()
         for hex_hash, raw_tx in pairs:
             if not raw_tx:
                 continue
             tx = deserializer(raw_tx).read_tx()
             for txin in tx.inputs:
-                spends.add((txin.prev_hash, txin.prev_idx))
-        return spends
+                result.add((txin.prev_hash, txin.prev_idx))
+        return result
 
     def value(self, hashX):
         '''Return the unconfirmed amount in the mempool for hashX.