wallet: auto sync outputs and key images in cold signing files

When passing around unsigned and signed transactions, outputs
and key images are passed along (outputs are passed along unsigned
transactions from the hot wallet to the cold wallet, key images
are passed along with signed transations from the cold wallet
to the hot wallet), to allow more user friendly syncing between
hot and cold wallets.

src/wallet/wallet2.cpp

@@ -2953,6 +2953,7 @@ bool wallet2::save_tx(const std::vector<pending_tx>& ptx_vector, const std::stri
   unsigned_tx_set txs;
   for (auto &tx: ptx_vector)
     txs.txes.push_back(tx.construction_data);
+  txs.transfers = m_transfers;
   std::string s = obj_to_json_str(txs);
   if (s.empty())
     return false;
@@ -2963,7 +2964,7 @@ bool wallet2::save_tx(const std::vector<pending_tx>& ptx_vector, const std::stri
   return epee::file_io_utils::save_string_to_file(filename, std::string(UNSIGNED_TX_PREFIX) + s);
 }
 //----------------------------------------------------------------------------------------------------
-bool wallet2::sign_tx(const std::string &unsigned_filename, const std::string &signed_filename, std::function<bool(const unsigned_tx_set&)> accept_func)
+bool wallet2::sign_tx(const std::string &unsigned_filename, const std::string &signed_filename, std::vector<wallet2::pending_tx> &txs, std::function<bool(const unsigned_tx_set&)> accept_func)
 {
   std::string s;
   boost::system::error_code errcode;
@@ -2998,6 +2999,8 @@ bool wallet2::sign_tx(const std::string &unsigned_filename, const std::string &s
     return false;
   }
 
+  import_outputs(exported_txs.transfers);
+
   // sign the transactions
   signed_tx_set signed_txes;
   for (size_t n = 0; n < exported_txs.txes.size(); ++n)
@@ -3043,6 +3046,17 @@ bool wallet2::sign_tx(const std::string &unsigned_filename, const std::string &s
     ptx.tx_key = rct::rct2sk(rct::identity()); // don't send it back to the untrusted view wallet
     ptx.dests = sd.splitted_dsts;
     ptx.construction_data = sd;
+
+    txs.push_back(ptx);
+  }
+
+  // add key images
+  signed_txes.key_images.resize(m_transfers.size());
+  for (size_t i = 0; i < m_transfers.size(); ++i)
+  {
+    if (!m_transfers[i].m_key_image_known)
+      LOG_PRINT_L0("WARNING: key image not known in signing wallet at index " << i);
+    signed_txes.key_images[i] = m_transfers[i].m_key_image;
   }
 
   s = obj_to_json_str(signed_txes);
@@ -3092,6 +3106,23 @@ bool wallet2::load_tx(const std::string &signed_filename, std::vector<tools::wal
     return false;
   }
 
+  // import key images
+  if (signed_txs.key_images.size() > m_transfers.size())
+  {
+    LOG_PRINT_L1("More key images returned that we know outputs for");
+    return false;
+  }
+  for (size_t i = 0; i < signed_txs.key_images.size(); ++i)
+  {
+    transfer_details &td = m_transfers[i];
+    if (td.m_key_image_known && td.m_key_image != signed_txs.key_images[i])
+      LOG_PRINT_L0("WARNING: imported key image differs from previously known key image at index " << i << ": trusting imported one");
+    td.m_key_image = signed_txs.key_images[i];
+    m_key_images[m_transfers[i].m_key_image] = i;
+    td.m_key_image_known = true;
+    m_pub_keys[m_transfers[i].get_public_key()] = i;
+  }
+
   ptx = signed_txs.ptx;
 
   return true;

src/wallet/wallet2.h

@@ -133,6 +133,21 @@ namespace tools
       bool is_rct() const { return m_rct; }
       uint64_t amount() const { return m_amount; }
       const crypto::public_key &get_public_key() const { return boost::get<const cryptonote::txout_to_key>(m_tx.vout[m_internal_output_index].target).key; }
+
+      BEGIN_SERIALIZE_OBJECT()
+        FIELD(m_block_height)
+        FIELD(m_tx)
+        FIELD(m_txid)
+        FIELD(m_internal_output_index)
+        FIELD(m_global_output_index)
+        FIELD(m_spent)
+        FIELD(m_spent_height)
+        FIELD(m_key_image)
+        FIELD(m_mask)
+        FIELD(m_amount)
+        FIELD(m_rct)
+        FIELD(m_key_image_known)
+      END_SERIALIZE()
     };
 
     struct payment_details
@@ -226,16 +241,20 @@ namespace tools
     struct unsigned_tx_set
     {
       std::vector<tx_construction_data> txes;
+      wallet2::transfer_container transfers;
       BEGIN_SERIALIZE_OBJECT()
         FIELD(txes)
+        FIELD(transfers)
       END_SERIALIZE()
     };
 
     struct signed_tx_set
     {
       std::vector<pending_tx> ptx;
+      std::vector<crypto::key_image> key_images;
       BEGIN_SERIALIZE_OBJECT()
         FIELD(ptx)
+        FIELD(key_images)
       END_SERIALIZE()
     };
 
@@ -377,7 +396,7 @@ namespace tools
     void commit_tx(pending_tx& ptx_vector);
     void commit_tx(std::vector<pending_tx>& ptx_vector);
     bool save_tx(const std::vector<pending_tx>& ptx_vector, const std::string &filename);
-    bool sign_tx(const std::string &unsigned_filename, const std::string &signed_filename, std::function<bool(const unsigned_tx_set&)> accept_func = NULL);
+    bool sign_tx(const std::string &unsigned_filename, const std::string &signed_filename, std::vector<wallet2::pending_tx> &ptx, std::function<bool(const unsigned_tx_set&)> accept_func = NULL);
     bool load_tx(const std::string &signed_filename, std::vector<tools::wallet2::pending_tx> &ptx, std::function<bool(const signed_tx_set&)> accept_func = NULL);
     std::vector<pending_tx> create_transactions(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, uint32_t priority, const std::vector<uint8_t> extra, bool trusted_daemon);
     std::vector<wallet2::pending_tx> create_transactions_2(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, uint32_t priority, const std::vector<uint8_t> extra, bool trusted_daemon);