Add change indicator for notes

qa/pull-tester/rpc-tests.sh

@@ -15,6 +15,7 @@ testScripts=(
     'prioritisetransaction.py'
     'wallet_treestate.py'
     'wallet_anchorfork.py'
+    'wallet_changeindicator.py'
     'wallet_protectcoinbase.py'
     'wallet_shieldcoinbase.py'
     'wallet_mergetoaddress.py'

qa/rpc-tests/wallet_changeindicator.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python2
+# Copyright (c) 2018 The Zcash developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal, assert_true, assert_false, wait_and_assert_operationid_status
+
+from decimal import Decimal
+
+class WalletChangeIndicatorTest (BitcoinTestFramework):
+    # Helper Methods
+    def generate_and_sync(self):
+        self.sync_all()
+        self.nodes[0].generate(1)
+        self.sync_all()
+
+    # Tests
+    def run_test(self):
+        taddr = self.nodes[1].getnewaddress()
+        zaddr1 = self.nodes[1].z_getnewaddress()
+        zaddr2 = self.nodes[1].z_getnewaddress()
+
+        self.nodes[0].sendtoaddress(taddr, Decimal('1.0'))
+        self.generate_and_sync()
+
+        # Send 1 ZEC to a zaddr
+        wait_and_assert_operationid_status(self.nodes[1], self.nodes[1].z_sendmany(taddr, [{'address': zaddr1, 'amount': 1.0, 'memo': 'c0ffee01'}], 1, 0))
+        self.generate_and_sync()
+
+        # Check that we have received 1 note which is not change
+        receivedbyaddress = self.nodes[1].z_listreceivedbyaddress(zaddr1, 0)
+        listunspent = self.nodes[1].z_listunspent()
+        assert_equal(1, len(receivedbyaddress), "Should have received 1 note")
+        assert_false(receivedbyaddress[0]['change'], "Note should not be change")
+        assert_equal(1, len(listunspent), "Should have 1 unspent note")
+        assert_false(listunspent[0]['change'], "Unspent note should not be change")
+
+        # Generate some change
+        wait_and_assert_operationid_status(self.nodes[1], self.nodes[1].z_sendmany(zaddr1, [{'address': zaddr2, 'amount': 0.6, 'memo': 'c0ffee02'}], 1, 0))
+        self.generate_and_sync()
+
+        # Check zaddr1 received
+        sortedreceived1 = sorted(self.nodes[1].z_listreceivedbyaddress(zaddr1, 0), key = lambda received: received['amount'])
+        assert_equal(2, len(sortedreceived1), "zaddr1 Should have received 2 notes")
+        assert_equal(Decimal('0.4'), sortedreceived1[0]['amount'])
+        assert_true(sortedreceived1[0]['change'], "Note valued at 0.4 should be change")
+        assert_equal(Decimal('1.0'), sortedreceived1[1]['amount'])
+        assert_false(sortedreceived1[1]['change'], "Note valued at 1.0 should not be change")
+        # Check zaddr2 received
+        sortedreceived2 = sorted(self.nodes[1].z_listreceivedbyaddress(zaddr2, 0), key = lambda received: received['amount'])
+        assert_equal(1, len(sortedreceived2), "zaddr2 Should have received 1 notes")
+        assert_equal(Decimal('0.6'), sortedreceived2[0]['amount'])
+        assert_false(sortedreceived2[0]['change'], "Note valued at 0.6 should not be change")
+        # Check unspent
+        sortedunspent = sorted(self.nodes[1].z_listunspent(), key = lambda received: received['amount'])
+        assert_equal(2, len(sortedunspent), "Should have 2 unspent notes")
+        assert_equal(Decimal('0.4'), sortedunspent[0]['amount'])
+        assert_true(sortedunspent[0]['change'], "Unspent note valued at 0.4 should be change")
+        assert_equal(Decimal('0.6'), sortedunspent[1]['amount'])
+        assert_false(sortedunspent[1]['change'], "Unspent note valued at 0.6 should not be change")
+
+if __name__ == '__main__':
+    WalletChangeIndicatorTest().main()

src/wallet/rpcwallet.cpp

@@ -2469,6 +2469,7 @@ UniValue z_listunspent(const UniValue& params, bool fHelp)
             "    \"address\" : \"address\",    (string) the shielded address\n"
             "    \"amount\": xxxxx,          (numeric) the amount of value in the note\n"
             "    \"memo\": xxxxx,            (string) hexademical string representation of memo field\n"
+            "    \"change\": true|false,     (boolean) true if the address that received the note is also one of the sending addresses\n"
             "  }\n"
             "  ,...\n"
             "]\n"
@@ -2548,9 +2549,10 @@ UniValue z_listunspent(const UniValue& params, bool fHelp)
     if (zaddrs.size() > 0) {
         std::vector<CUnspentSproutNotePlaintextEntry> entries;
         pwalletMain->GetUnspentFilteredNotes(entries, zaddrs, nMinDepth, nMaxDepth, !fIncludeWatchonly);
+        std::set<std::pair<PaymentAddress, uint256>> nullifierSet = pwalletMain->GetNullifiersForAddresses(zaddrs);
         for (CUnspentSproutNotePlaintextEntry & entry : entries) {
             UniValue obj(UniValue::VOBJ);
-            obj.push_back(Pair("txid",entry.jsop.hash.ToString()));
+            obj.push_back(Pair("txid", entry.jsop.hash.ToString()));
             obj.push_back(Pair("jsindex", (int)entry.jsop.js ));
             obj.push_back(Pair("jsoutindex", (int)entry.jsop.n));
             obj.push_back(Pair("confirmations", entry.nHeight));
@@ -2559,6 +2561,7 @@ UniValue z_listunspent(const UniValue& params, bool fHelp)
             obj.push_back(Pair("amount", ValueFromAmount(CAmount(entry.plaintext.value()))));
             std::string data(entry.plaintext.memo().begin(), entry.plaintext.memo().end());
             obj.push_back(Pair("memo", HexStr(data)));
+            obj.push_back(Pair("change", pwalletMain->IsNoteChange(nullifierSet, entry.address, entry.jsop)));
             results.push_back(obj);
         }
     }
@@ -3206,9 +3209,10 @@ UniValue z_listreceivedbyaddress(const UniValue& params, bool fHelp)
             "2. minconf          (numeric, optional, default=1) Only include transactions confirmed at least this many times.\n"
             "\nResult:\n"
             "{\n"
-            "  \"txid\": xxxxx,     (string) the transaction id\n"
-            "  \"amount\": xxxxx,   (numeric) the amount of value in the note\n"
-            "  \"memo\": xxxxx,     (string) hexademical string representation of memo field\n"
+            "  \"txid\": xxxxx,           (string) the transaction id\n"
+            "  \"amount\": xxxxx,         (numeric) the amount of value in the note\n"
+            "  \"memo\": xxxxx,           (string) hexademical string representation of memo field\n"
+            "  \"change\": true|false,    (boolean) true if the address that received the note is also one of the sending addresses\n"
             "}\n"
             "\nExamples:\n"
             + HelpExampleCli("z_listreceivedbyaddress", "\"ztfaW34Gj9FrnGUEf833ywDVL62NWXBM81u6EQnM6VR45eYnXhwztecW1SjxA7JrmAXKJhxhj3vDNEpVCQoSvVoSpmbhtjf\"")
@@ -3244,21 +3248,22 @@ UniValue z_listreceivedbyaddress(const UniValue& params, bool fHelp)
     UniValue result(UniValue::VARR);
     std::vector<CSproutNotePlaintextEntry> entries;
     pwalletMain->GetFilteredNotes(entries, fromaddress, nMinDepth, false, false);
+    std::set<std::pair<PaymentAddress, uint256>> nullifierSet = pwalletMain->GetNullifiersForAddresses({zaddr});
     for (CSproutNotePlaintextEntry & entry : entries) {
         UniValue obj(UniValue::VOBJ);
-        obj.push_back(Pair("txid",entry.jsop.hash.ToString()));
+        obj.push_back(Pair("txid", entry.jsop.hash.ToString()));
         obj.push_back(Pair("amount", ValueFromAmount(CAmount(entry.plaintext.value()))));
         std::string data(entry.plaintext.memo().begin(), entry.plaintext.memo().end());
         obj.push_back(Pair("memo", HexStr(data)));
         // (txid, jsindex, jsoutindex) is needed to globally identify a note
         obj.push_back(Pair("jsindex", entry.jsop.js));
         obj.push_back(Pair("jsoutindex", entry.jsop.n));
+        obj.push_back(Pair("change", pwalletMain->IsNoteChange(nullifierSet, entry.address, entry.jsop)));
         result.push_back(obj);
     }
     return result;
 }
 
-
 UniValue z_getbalance(const UniValue& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))

src/wallet/wallet.cpp

@@ -421,6 +421,40 @@ void CWallet::SetBestChain(const CBlockLocator& loc)
     SetBestChainINTERNAL(walletdb, loc);
 }
 
+std::set<std::pair<libzcash::PaymentAddress, uint256>> CWallet::GetNullifiersForAddresses(const std::set<libzcash::PaymentAddress> & addresses)
+{
+    std::set<std::pair<libzcash::PaymentAddress, uint256>> nullifierSet;
+    for (const auto & txPair : mapWallet) {
+        for (const auto & noteDataPair : txPair.second.mapNoteData) {
+            if (noteDataPair.second.nullifier && addresses.count(noteDataPair.second.address)) {
+                nullifierSet.insert(std::make_pair(noteDataPair.second.address, noteDataPair.second.nullifier.get()));
+            }
+        }
+    }
+    return nullifierSet;
+}
+
+bool CWallet::IsNoteChange(const std::set<std::pair<libzcash::PaymentAddress, uint256>> & nullifierSet, const PaymentAddress & address, const JSOutPoint & jsop)
+{
+    // A Note is marked as "change" if the address that received it
+    // also spent Notes in the same transaction. This will catch,
+    // for instance:
+    // - Change created by spending fractions of Notes (because
+    //   z_sendmany sends change to the originating z-address).
+    // - "Chaining Notes" used to connect JoinSplits together.
+    // - Notes created by consolidation transactions (e.g. using
+    //   z_mergetoaddress).
+    // - Notes sent from one address to itself.
+    for (const JSDescription & jsd : mapWallet[jsop.hash].vjoinsplit) {
+        for (const uint256 & nullifier : jsd.nullifiers) {
+            if (nullifierSet.count(std::make_pair(address, nullifier))) {
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
 bool CWallet::SetMinVersion(enum WalletFeature nVersion, CWalletDB* pwalletdbIn, bool fExplicit)
 {
     LOCK(cs_wallet); // nWalletVersion

src/wallet/wallet.h

@@ -1065,6 +1065,8 @@ class CWallet : public CCryptoKeyStore, public CValidationInterface
     void ChainTip(const CBlockIndex *pindex, const CBlock *pblock, ZCIncrementalMerkleTree tree, bool added);
     /** Saves witness caches and best block locator to disk. */
     void SetBestChain(const CBlockLocator& loc);
+    std::set<std::pair<libzcash::PaymentAddress, uint256>> GetNullifiersForAddresses(const std::set<libzcash::PaymentAddress> & addresses);
+    bool IsNoteChange(const std::set<std::pair<libzcash::PaymentAddress, uint256>> & nullifierSet, const libzcash::PaymentAddress & address, const JSOutPoint & entry);
 
     DBErrors LoadWallet(bool& fFirstRunRet);
     DBErrors ZapWalletTx(std::vector<CWalletTx>& vWtx);