wallet: add freeze/thaw/frozen commands

These commands let one freeze outputs by key image, so they
do not appear in balance, nor are considered when creating
a transaction, etc

This is helpful when receiving an output from a suspected spy,
who might try to track your other outputs by seeing with what
other outputs it gets spent.

The frozen command may be used without parameters to list all
currently frozen outputs.

src/simplewallet/simplewallet.cpp

@@ -237,6 +237,9 @@ namespace
   const char* USAGE_MARK_OUTPUT_SPENT("mark_output_spent <amount>/<offset> | <filename> [add]");
   const char* USAGE_MARK_OUTPUT_UNSPENT("mark_output_unspent <amount>/<offset>");
   const char* USAGE_IS_OUTPUT_SPENT("is_output_spent <amount>/<offset>");
+  const char* USAGE_FREEZE("freeze <key_image>");
+  const char* USAGE_THAW("thaw <key_image>");
+  const char* USAGE_FROZEN("frozen <key_image>");
   const char* USAGE_VERSION("version");
   const char* USAGE_HELP("help [<command>]");
 
@@ -2025,6 +2028,74 @@ bool simple_wallet::save_known_rings(const std::vector<std::string> &args)
   return true;
 }
 
+bool simple_wallet::freeze_thaw(const std::vector<std::string> &args, bool freeze)
+{
+  if (args.empty())
+  {
+    fail_msg_writer() << boost::format(tr("usage: %s <key_image>|<pubkey>")) % (freeze ? "freeze" : "thaw");
+    return true;
+  }
+  crypto::key_image ki;
+  if (!epee::string_tools::hex_to_pod(args[0], ki))
+  {
+    fail_msg_writer() << tr("failed to parse key image");
+    return true;
+  }
+  try
+  {
+    if (freeze)
+      m_wallet->freeze(ki);
+    else
+      m_wallet->thaw(ki);
+  }
+  catch (const std::exception &e)
+  {
+    fail_msg_writer() << e.what();
+    return true;
+  }
+
+  return true;
+}
+
+bool simple_wallet::freeze(const std::vector<std::string> &args)
+{
+  return freeze_thaw(args, true);
+}
+
+bool simple_wallet::thaw(const std::vector<std::string> &args)
+{
+  return freeze_thaw(args, false);
+}
+
+bool simple_wallet::frozen(const std::vector<std::string> &args)
+{
+  if (args.empty())
+  {
+    size_t ntd = m_wallet->get_num_transfer_details();
+    for (size_t i = 0; i < ntd; ++i)
+    {
+      if (!m_wallet->frozen(i))
+        continue;
+      const tools::wallet2::transfer_details &td = m_wallet->get_transfer_details(i);
+      message_writer() << tr("Frozen: ") << td.m_key_image << " " << cryptonote::print_money(td.amount());
+    }
+  }
+  else
+  {
+    crypto::key_image ki;
+    if (!epee::string_tools::hex_to_pod(args[0], ki))
+    {
+      fail_msg_writer() << tr("failed to parse key image");
+      return true;
+    }
+    if (m_wallet->frozen(ki))
+      message_writer() << tr("Frozen: ") << ki;
+    else
+      message_writer() << tr("Not frozen: ") << ki;
+  }
+  return true;
+}
+
 bool simple_wallet::version(const std::vector<std::string> &args)
 {
   message_writer() << "Monero '" << MONERO_RELEASE_NAME << "' (v" << MONERO_VERSION_FULL << ")";
@@ -2600,7 +2671,7 @@ simple_wallet::simple_wallet()
                            tr(USAGE_INCOMING_TRANSFERS),
                            tr("Show the incoming transfers, all or filtered by availability and address index.\n\n"
                               "Output format:\n"
-                              "Amount, Spent(\"T\"|\"F\"), \"locked\"|\"unlocked\", RingCT, Global Index, Transaction Hash, Address Index, [Public Key, Key Image] "));
+                              "Amount, Spent(\"T\"|\"F\"), \"frozen\"|\"locked\"|\"unlocked\", RingCT, Global Index, Transaction Hash, Address Index, [Public Key, Key Image] "));
   m_cmd_binder.set_handler("payments",
                            boost::bind(&simple_wallet::show_payments, this, _1),
                            tr(USAGE_PAYMENTS),
@@ -3012,6 +3083,18 @@ simple_wallet::simple_wallet()
                            boost::bind(&simple_wallet::blackballed, this, _1),
                            tr(USAGE_IS_OUTPUT_SPENT),
                            tr("Checks whether an output is marked as spent"));
+  m_cmd_binder.set_handler("freeze",
+                           boost::bind(&simple_wallet::freeze, this, _1),
+                           tr(USAGE_FREEZE),
+                           tr("Freeze a single output by key image so it will not be used"));
+  m_cmd_binder.set_handler("thaw",
+                           boost::bind(&simple_wallet::thaw, this, _1),
+                           tr(USAGE_THAW),
+                           tr("Thaw a single output by key image so it may be used again"));
+  m_cmd_binder.set_handler("frozen",
+                           boost::bind(&simple_wallet::frozen, this, _1),
+                           tr(USAGE_FROZEN),
+                           tr("Checks whether a given output is currently frozen by key image"));
   m_cmd_binder.set_handler("version",
                            boost::bind(&simple_wallet::version, this, _1),
                            tr(USAGE_VERSION),
@@ -4987,7 +5070,7 @@ bool simple_wallet::show_incoming_transfers(const std::vector<std::string>& args
         boost::format("%21s%8s%12s%8s%16u%68s%16u%s") %
         print_money(td.amount()) %
         (td.m_spent ? tr("T") : tr("F")) %
-        (m_wallet->is_transfer_unlocked(td) ? tr("unlocked") : tr("locked")) %
+        (m_wallet->frozen(td) ? tr("[frozen]") : m_wallet->is_transfer_unlocked(td) ? tr("unlocked") : tr("locked")) %
         (td.is_rct() ? tr("RingCT") : tr("-")) %
         td.m_global_output_index %
         td.m_txid %