Get multisig working pre-FCMP++/Carrot fork

Reuse the background sync cache for multisig sync, so that upon
importing multisig info, the wallet doesn't need to rescan the
chain and instead can just process the background cache.

Author: j-berman

src/fcmp_pp/tree_cache.cpp

@@ -739,7 +739,7 @@ template<typename C1, typename C2>
 bool TreeCache<C1, C2>::register_output(const OutputPair &output)
 {
     auto output_ref_hash = get_output_ref_hash(output);
-    CHECK_AND_ASSERT_MES(m_registered_outputs.find(output_ref_hash) == m_registered_outputs.end(), false,
+    CHECK_AND_NO_ASSERT_MES_L1(m_registered_outputs.find(output_ref_hash) == m_registered_outputs.end(), false,
         "output is already registered");
 
     // Add to registered outputs container

src/wallet/wallet2.cpp

@@ -2654,7 +2654,8 @@ void wallet2::process_new_scanned_transaction(
       continue;
     const cryptonote::txin_to_key &in_to_key = boost::get<cryptonote::txin_to_key>(in);
     auto it = m_key_images.find(in_to_key.k_image);
-    if(it != m_key_images.end())
+    const bool key_image_known = it != m_key_images.end();
+    if(key_image_known)
     {
       transfer_details& td = m_transfers[it->second];
       uint64_t amount = in_to_key.amount;
@@ -2691,7 +2692,9 @@ void wallet2::process_new_scanned_transaction(
       }
     }
 
-    if (!pool && (m_track_uses || (m_background_syncing && it == m_key_images.end())))
+    const bool check_if_possibly_spent = !pool && (m_track_uses ||
+      (!key_image_known && (m_background_syncing || m_multisig)));
+    if (check_if_possibly_spent)
     {
       const uint64_t amount = in_to_key.amount;
       std::vector<uint64_t> offsets = cryptonote::relative_output_offsets_to_absolute(in_to_key.key_offsets);
@@ -2717,12 +2720,12 @@ void wallet2::process_new_scanned_transaction(
   const bool possibly_involved_with_tx = received_an_output || recognized_owned_possibly_spent_enote;
   const bool should_cache_bg_tx = possibly_involved_with_tx
     && !pool
-    && m_background_syncing
+    && (m_background_syncing || m_multisig)
     && !m_background_sync_data.txs.count(txid);
   if (should_cache_bg_tx)
   {
-    // we're going to re-process this receive when background sync is disabled
-    if (m_background_syncing && m_background_sync_data.txs.find(txid) == m_background_sync_data.txs.end())
+    // we're going to re-process this tx when we can generate the key images for receives
+    if (m_background_sync_data.txs.find(txid) == m_background_sync_data.txs.end())
     {
       size_t bgs_idx = m_background_sync_data.txs.size();
       background_synced_tx_t bgs_tx = {
@@ -2733,7 +2736,7 @@ void wallet2::process_new_scanned_transaction(
         .block_timestamp               = ts,
         .double_spend_seen             = double_spend_seen
       };
-      LOG_PRINT_L2("Adding received tx " << txid << " to background sync data (idx=" << bgs_idx << ")");
+      LOG_PRINT_L2("Adding tx " << txid << " to background sync data (idx=" << bgs_idx << ")");
       m_background_sync_data.txs.insert({txid, std::move(bgs_tx)});
     }
   }
@@ -4605,7 +4608,7 @@ void wallet2::refresh(bool trusted_daemon, uint64_t start_height, uint64_t & blo
   }
 
   m_first_refresh_done = true;
-  if (m_background_syncing || m_is_background_wallet)
+  if (m_background_syncing || m_is_background_wallet || m_multisig)
     m_background_sync_data.first_refresh_done = true;
 
   m_multisig_rescan_info = std::vector<std::vector<tools::wallet2::multisig_info>>{};
@@ -5999,6 +6002,7 @@ void wallet2::generate(const std::string& wallet_, const epee::wipeable_string&
 
   create_keys_file(wallet_, false, password, m_nettype != MAINNET || create_address_file);
   setup_new_blockchain();
+  reset_background_sync_data(m_background_sync_data);
 
   if (!wallet_.empty())
     store();
@@ -6331,6 +6335,7 @@ std::string wallet2::make_multisig(const epee::wipeable_string &password,
     this->create_keys_file(m_wallet_file, false, password, boost::filesystem::exists(m_wallet_file + ".address.txt"));
 
   this->setup_new_blockchain();
+  this->reset_background_sync_data(m_background_sync_data);
 
   if (!m_wallet_file.empty())
     this->store();
@@ -6560,7 +6565,7 @@ void wallet2::rewrite(const std::string& wallet_name, const epee::wipeable_strin
     store_background_keys(m_custom_background_key.get());
     store_background_cache(m_custom_background_key.get(), true/*do_reset_background_sync_data*/);
   }
-  else if (m_background_sync_type == BackgroundSyncReusePassword)
+  else if (m_background_sync_type == BackgroundSyncReusePassword || m_multisig)
   {
     reset_background_sync_data(m_background_sync_data);
   }
@@ -6875,8 +6880,7 @@ void wallet2::load(const std::string& wallet_, const epee::wipeable_string& pass
 
   try
   {
-    if (use_fs)
-      process_background_cache_on_open();
+    process_background_cache_on_open();
   }
   catch (const std::exception &e)
   {
@@ -7007,6 +7011,12 @@ void wallet2::load_wallet_cache(const bool use_fs, const std::string& cache_buf)
 //----------------------------------------------------------------------------------------------------
 void wallet2::process_background_cache_on_open()
 {
+  if (m_multisig)
+  {
+    if (!m_background_sync_data.first_refresh_done)
+      reset_background_sync_data(m_background_sync_data);
+    return;
+  }
   if (m_wallet_file.empty())
     return;
   if (m_background_syncing || m_is_background_wallet)
@@ -8469,14 +8479,15 @@ bool wallet2::parse_multisig_tx_from_str(std::string multisig_tx_st, multisig_tx
   for (const auto &ptx: exported_txs.m_ptx)
   {
     CHECK_AND_ASSERT_MES(ptx.selected_transfers.size() == ptx.tx.vin.size(), false, "Mismatched selected_transfers/vin sizes");
+    const tools::wallet2::tx_construction_data &sd = get_construction_data(ptx);
     for (size_t idx: ptx.selected_transfers)
       CHECK_AND_ASSERT_MES(idx < m_transfers.size(), false, "Transfer index out of range");
-    CHECK_AND_ASSERT_MES(get_construction_data(ptx).selected_transfers.size() == ptx.tx.vin.size(), false, "Mismatched cd selected_transfers/vin sizes");
-    for (size_t idx: get_construction_data(ptx).selected_transfers)
+    CHECK_AND_ASSERT_MES(sd.selected_transfers.size() == ptx.tx.vin.size(), false, "Mismatched cd selected_transfers/vin sizes");
+    for (size_t idx: sd.selected_transfers)
       CHECK_AND_ASSERT_MES(idx < m_transfers.size(), false, "Transfer index out of range");
-    CHECK_AND_ASSERT_MES(get_construction_data(ptx).sources.size() == ptx.tx.vin.size(), false, "Mismatched sources/vin sizes");
+    CHECK_AND_ASSERT_MES(sd.sources.size() == ptx.tx.vin.size(), false, "Mismatched sources/vin sizes");
     CHECK_AND_ASSERT_MES(!ptx.tx.vin.empty(), false, "Multisig tx has no inputs");
-    CHECK_AND_ASSERT_MES(!get_construction_data(ptx).sources.empty(), false, "Multisig tx has no sources");
+    CHECK_AND_ASSERT_MES(!sd.sources.empty(), false, "Multisig tx has no sources");
   }
 
   return true;
@@ -13960,7 +13971,7 @@ void wallet2::process_background_cache(const background_sync_data_t &background_
     m_processing_background_cache = false;
   });
 
-  if (m_background_syncing || m_multisig || m_watch_only || key_on_device())
+  if (m_background_syncing || m_watch_only || key_on_device())
     return;
 
   if (!background_sync_data.first_refresh_done)
@@ -15088,32 +15099,35 @@ size_t wallet2::import_multisig(std::vector<cryptonote::blobdata> blobs, bool re
     std::sort(m_multisig_rescan_info.begin(), m_multisig_rescan_info.end(), [](const std::vector<tools::wallet2::multisig_info> &i0, const std::vector<tools::wallet2::multisig_info> &i1){ return memcmp(&i0[0].m_signer, &i1[0].m_signer, sizeof(i0[0].m_signer)) < 0; });
   }
 
-  // first pass to determine where to detach the blockchain
-  for (size_t n = 0; n < n_outputs; ++n)
+  for (size_t n = 0; n < n_outputs && n < m_transfers.size(); ++n)
   {
-    const transfer_details &td = m_transfers[n];
-    if (!td.m_key_image_partial)
+    update_multisig_rescan_info(m_multisig_rescan_k, m_multisig_rescan_info, n);
+  }
+
+  // The background cache should have all txs saved which need to be rescanned, including potential spends. We process
+  // the background cache with multisig info loaded.
+  const background_sync_data_t background_sync_data = m_background_sync_data;
+  const hashchain blockchain = m_blockchain;
+  const TreeCacheV1 tree_cache = m_tree_cache;
+  process_background_cache(background_sync_data, blockchain, m_last_block_reward, tree_cache);
+
+  // Once all key images are known and we've processed the background cache, any txs present in the background
+  // cache are no longer useful to us. They've been processed, we can remove them.
+  bool all_kis_known = true;
+  for (const auto &td : m_transfers)
+  {
+    if (td.m_key_image_known)
       continue;
-    // FIXME: if we need to pop more blocks from the tree cache than the reorg depth, and the wallet has received
-    // outputs from before the detach height, then the wallet won't be able to correct those prior output paths.
-    // Some solutions:
-    // A) restart sync from the wallet's first received output height.
-    // B) re-request output paths from the daemon.
-    // C) multisig wallet should stop syncing upon identifying a receive.
-    MINFO("Multisig info importing from block height " << td.m_block_height);
-    auto output_tracker_cache = create_output_tracker_cache();
-    handle_reorg(td.m_block_height, output_tracker_cache);
+    all_kis_known = false;
     break;
   }
 
-  for (size_t n = 0; n < n_outputs && n < m_transfers.size(); ++n)
+  if (all_kis_known)
   {
-    update_multisig_rescan_info(m_multisig_rescan_k, m_multisig_rescan_info, n);
+    MDEBUG("All key images are known, clearing background sync data since we don't need it anymore");
+    reset_background_sync_data(m_background_sync_data);
   }
 
-  if (refresh_after_import)
-    refresh(false);
-
   return n_outputs;
 }
 //----------------------------------------------------------------------------------------------------