wallet2: fix rescanning tx via scan_tx

- Detach & re-process txs >= lowest scan height
- ensures that if a user calls scan_tx(tx1) after scanning tx2,
the wallet correctly processes tx1 and tx2
- if a user provides a tx with a height higher than the wallet's
last scanned height, the wallet will scan starting from that tx's
height
- scan_tx requires trusted daemon iff need to re-process existing
txs: in addition to querying a daemon for txids, if a user
provides a txid of a tx with height *lower* than any *already*
scanned txs in the wallet, then the wallet will also query the
daemon for all the *higher* txs as well. This is likely
unexpected behavior to a caller, and so to protect a caller from
revealing txid's to an untrusted daemon in an unexpected way,
require the daemon be trusted.

1 files changed, 19 insertions, 0 deletions

diff --git a/src/wallet/wallet_errors.h b/src/wallet/wallet_errors.h
index 0b8512163..fcf2ddd93 100644
--- a/src/wallet/wallet_errors.h
+++ b/src/wallet/wallet_errors.h
@@ -93,6 +93,8 @@ namespace tools
     //         get_output_distribution
     //         payment_required
     //       wallet_files_doesnt_correspond
+    //       scan_tx_error *
+    //         wont_reprocess_recent_txs_via_untrusted_daemon
     //
     // * - class with protected ctor
 
@@ -915,6 +917,23 @@ namespace tools
       }
     };
     //----------------------------------------------------------------------------------------------------
+    struct scan_tx_error : public wallet_logic_error
+    {
+    protected:
+      explicit scan_tx_error(std::string&& loc, const std::string& message)
+        : wallet_logic_error(std::move(loc), message)
+      {
+      }
+    };
+    //----------------------------------------------------------------------------------------------------
+    struct wont_reprocess_recent_txs_via_untrusted_daemon : public scan_tx_error
+    {
+      explicit wont_reprocess_recent_txs_via_untrusted_daemon(std::string&& loc)
+        : scan_tx_error(std::move(loc), "The wallet has already seen 1 or more recent transactions than the scanned tx")
+      {
+      }
+    };
+    //----------------------------------------------------------------------------------------------------
 
 #if !defined(_MSC_VER)