wallet: add a fee multiplier

Fee can now be multiplied by 2 or 3, if users want to give
priority to their transactions. There are only three levels
to avoid too much fingerprinting. Default is 1 (minimum fee).
The default multiplier can be set by "set fee-multiplier X".

1 files changed, 10 insertions, 0 deletions

diff --git a/src/wallet/wallet_errors.h b/src/wallet/wallet_errors.h
index 184d8a2a1..ea0b6a1f5 100644
--- a/src/wallet/wallet_errors.h
+++ b/src/wallet/wallet_errors.h
@@ -56,6 +56,7 @@ namespace tools
     //       file_read_error
     //       file_save_error
     //       invalid_password
+    //       invalid_fee_multiplier
     //       refresh_error *
     //         acc_outs_lookup_error
     //         block_parse_error
@@ -226,6 +227,15 @@ namespace tools
 
       std::string to_string() const { return wallet_logic_error::to_string(); }
     };
+    struct invalid_fee_multiplier : public wallet_logic_error
+    {
+      explicit invalid_fee_multiplier(std::string&& loc)
+        : wallet_logic_error(std::move(loc), "invalid fee multiplier")
+      {
+      }
+
+      std::string to_string() const { return wallet_logic_error::to_string(); }
+    };
 
     //----------------------------------------------------------------------------------------------------
     struct invalid_pregenerated_random : public wallet_logic_error